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Sample records for thyrotropin structural elucidation

  1. Asparagine-linked oligosaccharides on lutropin, follitropin, and thyrotropin: structural elucidation of the sulfated and sialylated oligosaccharides on bovine, ovine, and human pituitary glycoprotein hormones

    International Nuclear Information System (INIS)

    Green, E.D.; Baenziger, J.U.

    1988-01-01

    The authors have elucidated the structures of the anionic asparagine-linked oligosaccharides present on the glycoprotein hormones lutropin (luteinizing hormone), follitropin (follicle-stimulating hormone), and thyrotropin (thyroid-stimulating hormone). Purified hormones, isolated from bovine, ovine, and human pituitaries, were digested with N-glycanase, and the released oligosaccharides were reduced with NaB[ 3 H] 4 . The 3 H-labeled oligosaccharides from each hormone were then fractionated by anion-exchange high performance liquid chromatography (HPLC) into populations differing in the number of sulfate and/or sialic acid moieties. The sulfated, sialylated, and sulfated/sialylated structures, which together comprised 67-90% of the asparagine-linked oligosaccharides on the pituitary glycoprotein hormones, were highly heterogeneous and displayed hormone- as well as animal species-specific features. A previously uncharacterized dibranched oligosaccharide, bearing one residue each of sulfate and sialic acid, was found on all of the hormones except bovine lutropin. In this study, they describe the purification and detailed structural characterizations of the sulfated, sialylated, and sulfated/sialylated oligosaccharides found on lutropin, follitropin, and thyrotropin from several animal species

  2. Structural elucidation of nanocrystalline biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Maltsev, S.

    2008-10-23

    Bone diseases, such as osteoporosis and osteoarthritis, are the second most prevalent health problem worldwide. In Germany approximately 5 millions people are affected by arthritis. Investigating biomineralization processes and bone molecular structure is of key importance for developing new drugs for preventing and healing bone diseases. Nuclear magnetic resonance (NMR) was the primary technique used due to its advantages in characterising poorly ordered and disordered materials. Compared to all the diffraction techniques that widely applied in structural investigations, the usefulness of NMR is independent of long range molecular order. This makes NMR an outstanding technique for studies of complex/amorphous materials. Conventional NMR experiments (single pulse, spin-echo, cross polarization (CP), etc.) as well as their modifications and high-end techniques (2D HETCOR, REDOR, etc.) were used in this work. Combining the contributions from different techniques enhances the information content of the investigations and can increase the precision of the overall conclusions. Also XRD, TEM and FTIR were applied to different extent in order to get a general idea of nanocrystalline hydroxyapatite crystallite structure. Results: - A new approach named 'Solid-state NMR spectroscopy using the lost I spin magnetization in polarization transfer experiments' has been developed for measuring the transferred I spin magnetization from abundant nuclei, which is normally lost when detecting the S spin magnetization. - A detailed investigation of nanocrystalline hydroxyapatite core was made to prove that proton environment of the phosphates units and phosphorus environment of hydroxyl units are the same as in highly crystalline hydroxyapatite sample. - Using XRD it was found that the surface of the hydroxyapatite nanocrystals is not completely disordered, as it was suggested before, but resembles the hydroxyapatite structure with HPO{sub 4}{sup 2-} (and some CO{sub 3}{sup

  3. Structural elucidation of nanocrystalline biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Maltsev, S

    2008-10-23

    Bone diseases, such as osteoporosis and osteoarthritis, are the second most prevalent health problem worldwide. In Germany approximately 5 millions people are affected by arthritis. Investigating biomineralization processes and bone molecular structure is of key importance for developing new drugs for preventing and healing bone diseases. Nuclear magnetic resonance (NMR) was the primary technique used due to its advantages in characterising poorly ordered and disordered materials. Compared to all the diffraction techniques that widely applied in structural investigations, the usefulness of NMR is independent of long range molecular order. This makes NMR an outstanding technique for studies of complex/amorphous materials. Conventional NMR experiments (single pulse, spin-echo, cross polarization (CP), etc.) as well as their modifications and high-end techniques (2D HETCOR, REDOR, etc.) were used in this work. Combining the contributions from different techniques enhances the information content of the investigations and can increase the precision of the overall conclusions. Also XRD, TEM and FTIR were applied to different extent in order to get a general idea of nanocrystalline hydroxyapatite crystallite structure. Results: - A new approach named 'Solid-state NMR spectroscopy using the lost I spin magnetization in polarization transfer experiments' has been developed for measuring the transferred I spin magnetization from abundant nuclei, which is normally lost when detecting the S spin magnetization. - A detailed investigation of nanocrystalline hydroxyapatite core was made to prove that proton environment of the phosphates units and phosphorus environment of hydroxyl units are the same as in highly crystalline hydroxyapatite sample. - Using XRD it was found that the surface of the hydroxyapatite nanocrystals is not completely disordered, as it was suggested before, but resembles the hydroxyapatite structure with HPO{sub 4}{sup 2-} (and some CO{sub 3}{sup 2

  4. Structure elucidation of secondary natural products

    International Nuclear Information System (INIS)

    Seger, C.

    2001-06-01

    The presented thesis deals with the structure elucidation of secondary natural products. Most of the compounds under investigation were terpenes, especially triterpenes, alkaloids and stilbenoids. Besides characterizing a multitude of already known and also new compounds, it was possible to detect and correct wrongly assigned literature data. The methodological aspect of this thesis lies - beside in the utilization of modern 2D NMR spectroscopy - in the evaluation of computer assisted structure elucidation (CASE) techniques in the course of spectroscopy supported structure elucidation processes. (author)

  5. Defining structural and functional dimensions of the extracellular thyrotropin receptor region.

    Science.gov (United States)

    Kleinau, Gunnar; Mueller, Sandra; Jaeschke, Holger; Grzesik, Paul; Neumann, Susanne; Diehl, Anne; Paschke, Ralf; Krause, Gerd

    2011-06-24

    The extracellular region of the thyrotropin receptor (TSHR) can be subdivided into the leucine-rich repeat domain (LRRD) and the hinge region. Both the LRRD and the hinge region interact with thyrotropin (TSH) or autoantibodies. Structural data for the TSHR LRRD were previously determined by crystallization (amino acids Glu(30)-Thr(257), 10 repeats), but the structure of the hinge region is still undefined. Of note, the amino acid sequence (Trp(258)-Tyr(279)) following the crystallized LRRD comprises a pattern typical for leucine-rich repeats with conserved hydrophobic side chains stabilizing the repeat fold. Moreover, functional data for amino acids between the LRRD and the transmembrane domain were fragmentary. We therefore investigated systematically these TSHR regions by mutagenesis to reveal insights into their functional contribution and potential structural features. We found that mutations of conserved hydrophobic residues between Thr(257) and Tyr(279) cause TSHR misfold, which supports a structural fold of this peptide, probably as an additional leucine-rich repeat. Furthermore, we identified several new mutations of hydrophilic amino acids in the entire hinge region leading to partial TSHR inactivation, indicating that these positions are important for intramolecular signal transduction. In summary, we provide new information regarding the structural features and functionalities of extracellular TSHR regions. Based on these insights and in context with previous results, we suggest an extracellular activation mechanism that supports an intramolecular agonistic unit as a central switch for activating effects at the extracellular region toward the serpentine domain.

  6. Spectroscopic databases - A tool for structure elucidation

    Energy Technology Data Exchange (ETDEWEB)

    Luksch, P [Fachinformationszentrum Karlsruhe, Gesellschaft fuer Wissenschaftlich-Technische Information mbH, Eggenstein-Leopoldshafen (Germany)

    1990-05-01

    Spectroscopic databases have developed to useful tools in the process of structure elucidation. Besides the conventional library searches, new intelligent programs have been added, that are able to predict structural features from measured spectra or to simulate for a given structure. The example of the C13NMR/IR database developed at BASF and available on STN is used to illustrate the present capabilities of online database. New developments in the field of spectrum simulation and methods for the prediction of complete structures from spectroscopic information are reviewed. (author). 10 refs, 5 figs.

  7. Using Genomics for Natural Product Structure Elucidation.

    Science.gov (United States)

    Tietz, Jonathan I; Mitchell, Douglas A

    2016-01-01

    Natural products (NPs) are the most historically bountiful source of chemical matter for drug development-especially for anti-infectives. With insights gleaned from genome mining, interest in natural product discovery has been reinvigorated. An essential stage in NP discovery is structural elucidation, which sheds light not only on the chemical composition of a molecule but also its novelty, properties, and derivatization potential. The history of structure elucidation is replete with techniquebased revolutions: combustion analysis, crystallography, UV, IR, MS, and NMR have each provided game-changing advances; the latest such advance is genomics. All natural products have a genetic basis, and the ability to obtain and interpret genomic information for structure elucidation is increasingly available at low cost to non-specialists. In this review, we describe the value of genomics as a structural elucidation technique, especially from the perspective of the natural product chemist approaching an unknown metabolite. Herein we first introduce the databases and programs of interest to the natural products chemist, with an emphasis on those currently most suited for general usability. We describe strategies for linking observed natural product-linked phenotypes to their corresponding gene clusters. We then discuss techniques for extracting structural information from genes, illustrated with numerous case examples. We also provide an analysis of the biases and limitations of the field with recommendations for future development. Our overview is not only aimed at biologically-oriented researchers already at ease with bioinformatic techniques, but also, in particular, at natural product, organic, and/or medicinal chemists not previously familiar with genomic techniques.

  8. Structural-Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work.

    Science.gov (United States)

    Kleinau, Gunnar; Worth, Catherine L; Kreuchwig, Annika; Biebermann, Heike; Marcinkowski, Patrick; Scheerer, Patrick; Krause, Gerd

    2017-01-01

    The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to

  9. Blind trials of computer-assisted structure elucidation software

    Directory of Open Access Journals (Sweden)

    Moser Arvin

    2012-02-01

    Full Text Available Abstract Background One of the largest challenges in chemistry today remains that of efficiently mining through vast amounts of data in order to elucidate the chemical structure for an unknown compound. The elucidated candidate compound must be fully consistent with the data and any other competing candidates efficiently eliminated without doubt by using additional data if necessary. It has become increasingly necessary to incorporate an in silico structure generation and verification tool to facilitate this elucidation process. An effective structure elucidation software technology aims to mimic the skills of a human in interpreting the complex nature of spectral data while producing a solution within a reasonable amount of time. This type of software is known as computer-assisted structure elucidation or CASE software. A systematic trial of the ACD/Structure Elucidator CASE software was conducted over an extended period of time by analysing a set of single and double-blind trials submitted by a global audience of scientists. The purpose of the blind trials was to reduce subjective bias. Double-blind trials comprised of data where the candidate compound was unknown to both the submitting scientist and the analyst. The level of expertise of the submitting scientist ranged from novice to expert structure elucidation specialists with experience in pharmaceutical, industrial, government and academic environments. Results Beginning in 2003, and for the following nine years, the algorithms and software technology contained within ACD/Structure Elucidator have been tested against 112 data sets; many of these were unique challenges. Of these challenges 9% were double-blind trials. The results of eighteen of the single-blind trials were investigated in detail and included problems of a diverse nature with many of the specific challenges associated with algorithmic structure elucidation such as deficiency in protons, structure symmetry, a large number of

  10. Mayotlide: synthetic approaches and structural elucidation

    OpenAIRE

    Herraiz Cobo, Jesús

    2017-01-01

    [eng] Mayotlide is a marine peptide isolated by PharmaMar S.A. from Spongia sp.. The sequence of the aminoacids were achieved by MS-MS spectrometry, where two of them were tryptophans. The NMR spectroscopy revealed the presence of N1-C3a bond between the tryptophans, which means that one of them was cyclized. On the first structure proposal, the aminoacids were forming two macrocyclic rings: on the ring B, all the aminoacids of molecule were tied by amide bond, remarking the presence of the ...

  11. Mayotlide: synthetic approaches and structural elucidation

    OpenAIRE

    Herraiz Cobo, Jesús

    2017-01-01

    Mayotlide is a marine peptide isolated by PharmaMar S.A. from Spongia sp.. The sequence of the aminoacids were achieved by MS-MS spectrometry, where two of them were tryptophans. The NMR spectroscopy revealed the presence of N1-C3a bond between the tryptophans, which means that one of them was cyclized. On the first structure proposal, the aminoacids were forming two macrocyclic rings: on the ring B, all the aminoacids of molecule were tied by amide bond, remarking the presence of the cycliz...

  12. Transcription initiation complex structures elucidate DNA opening.

    Science.gov (United States)

    Plaschka, C; Hantsche, M; Dienemann, C; Burzinski, C; Plitzko, J; Cramer, P

    2016-05-19

    Transcription of eukaryotic protein-coding genes begins with assembly of the RNA polymerase (Pol) II initiation complex and promoter DNA opening. Here we report cryo-electron microscopy (cryo-EM) structures of yeast initiation complexes containing closed and open DNA at resolutions of 8.8 Å and 3.6 Å, respectively. DNA is positioned and retained over the Pol II cleft by a network of interactions between the TATA-box-binding protein TBP and transcription factors TFIIA, TFIIB, TFIIE, and TFIIF. DNA opening occurs around the tip of the Pol II clamp and the TFIIE 'extended winged helix' domain, and can occur in the absence of TFIIH. Loading of the DNA template strand into the active centre may be facilitated by movements of obstructing protein elements triggered by allosteric binding of the TFIIE 'E-ribbon' domain. The results suggest a unified model for transcription initiation with a key event, the trapping of open promoter DNA by extended protein-protein and protein-DNA contacts.

  13. Extended and structurally supported insights into extracellular hormone binding, signal transduction and organization of the thyrotropin receptor.

    Directory of Open Access Journals (Sweden)

    Gerd Krause

    Full Text Available The hormone thyrotropin (TSH and its receptor (TSHR are crucial for the growth and function of the thyroid gland. The TSHR is evolutionary linked with the receptors of follitropin (FSHR and lutropin/choriogonadotropin (LHR and their sequences and structures are similar. The extracellular region of TSHR contains more than 350 amino acids and binds hormone and antibodies. Several important questions related to functions and mechanisms of TSHR are still not comprehensively understood. One major reason for these open questions is the lack of any structural information about the extracellular segment of TSHR that connects the N-terminal leucine-rich repeat domain (LRRD with the transmembrane helix (TMH 1, the hinge region. It has been shown experimentally that this segment is important for fine tuning of signaling and ligand interactions. A new crystal structure containing most of the extracellular hFSHR region in complex with hFSH has recently been published. Now, we have applied these new structural insights to the homologous TSHR and have generated a structural model of the TSHR LRRD/hinge-region/TSH complex. This structural model is combined and evaluated with experimental data including hormone binding (bTSH, hTSH, thyrostimulin, super-agonistic effects, antibody interactions and signaling regulation. These studies and consideration of significant and non-significant amino acids have led to a new description of mechanisms at the TSHR, including ligand-induced displacements of specific hinge region fragments. This event triggers conformational changes at a convergent center of the LRRD and the hinge region, activating an "intramolecular agonistic unit" close to the transmembrane domain.

  14. Extended and structurally supported insights into extracellular hormone binding, signal transduction and organization of the thyrotropin receptor.

    Science.gov (United States)

    Krause, Gerd; Kreuchwig, Annika; Kleinau, Gunnar

    2012-01-01

    The hormone thyrotropin (TSH) and its receptor (TSHR) are crucial for the growth and function of the thyroid gland. The TSHR is evolutionary linked with the receptors of follitropin (FSHR) and lutropin/choriogonadotropin (LHR) and their sequences and structures are similar. The extracellular region of TSHR contains more than 350 amino acids and binds hormone and antibodies. Several important questions related to functions and mechanisms of TSHR are still not comprehensively understood. One major reason for these open questions is the lack of any structural information about the extracellular segment of TSHR that connects the N-terminal leucine-rich repeat domain (LRRD) with the transmembrane helix (TMH) 1, the hinge region. It has been shown experimentally that this segment is important for fine tuning of signaling and ligand interactions. A new crystal structure containing most of the extracellular hFSHR region in complex with hFSH has recently been published. Now, we have applied these new structural insights to the homologous TSHR and have generated a structural model of the TSHR LRRD/hinge-region/TSH complex. This structural model is combined and evaluated with experimental data including hormone binding (bTSH, hTSH, thyrostimulin), super-agonistic effects, antibody interactions and signaling regulation. These studies and consideration of significant and non-significant amino acids have led to a new description of mechanisms at the TSHR, including ligand-induced displacements of specific hinge region fragments. This event triggers conformational changes at a convergent center of the LRRD and the hinge region, activating an "intramolecular agonistic unit" close to the transmembrane domain.

  15. Structure elucidation of a novel oligosaccharide (Medalose) from camel milk

    Science.gov (United States)

    Gangwar, Lata; Singh, Rinku; Deepak, Desh

    2018-02-01

    Free oligosaccharides are the third most abundant solid component in milk after lactose and lipids. The study of milk oligosaccharides indicate that nutrients are not only benefits the infant's gut but also perform a number of other functions which include stimulation of growth, receptor analogues to inhibit binding of pathogens and substances that promote postnatal brain development. Surveys reveal that camel milk oligosaccharides possess varied biological activities that help in the treatment of diabetes, asthma, anaemia, piles and also a food supplement to milking mothers. In this research, camel milk was selected for its oligosaccharide contents, which was then processed by Kobata and Ginsburg method followed by the HPLC and CC techniques. Structure elucidation of isolated compound was done by the chemical degradation, chemical transformation and comparison of chemical shift of NMR data of natural and acetylated oligosaccharide structure reporter group theory, the 1H, 13C NMR, 2D-NMR (COSY, TOCSY and HSQC) techniques, and mass spectrometry. The structure was elucidated as under: MEDALOSE

  16. Elucidation of Operon Structures across Closely Related Bacterial Genomes

    Science.gov (United States)

    Li, Guojun

    2014-01-01

    About half of the protein-coding genes in prokaryotic genomes are organized into operons to facilitate co-regulation during transcription. With the evolution of genomes, operon structures are undergoing changes which could coordinate diverse gene expression patterns in response to various stimuli during the life cycle of a bacterial cell. Here we developed a graph-based model to elucidate the diversity of operon structures across a set of closely related bacterial genomes. In the constructed graph, each node represents one orthologous gene group (OGG) and a pair of nodes will be connected if any two genes, from the corresponding two OGGs respectively, are located in the same operon as immediate neighbors in any of the considered genomes. Through identifying the connected components in the above graph, we found that genes in a connected component are likely to be functionally related and these identified components tend to form treelike topology, such as paths and stars, corresponding to different biological mechanisms in transcriptional regulation as follows. Specifically, (i) a path-structure component integrates genes encoding a protein complex, such as ribosome; and (ii) a star-structure component not only groups related genes together, but also reflects the key functional roles of the central node of this component, such as the ABC transporter with a transporter permease and substrate-binding proteins surrounding it. Most interestingly, the genes from organisms with highly diverse living environments, i.e., biomass degraders and animal pathogens of clostridia in our study, can be clearly classified into different topological groups on some connected components. PMID:24959722

  17. Isolation and structure elucidation of a neuropeptide from three ...

    African Journals Online (AJOL)

    1993-03-03

    Mar 3, 1993 ... determination of the primary structure by pulsed·liquid phase sequencing employing Edman chemistry .... in cockroaches and haemo1ymph lipids in locusts (Glide ..... 15 ()()() described species), and higher classification is still.

  18. Elucidating the vacuum structure of the Aoki phase

    International Nuclear Information System (INIS)

    Azcoiti, Vicente; Di Carlo, Giuseppe; Follana, Eduardo; Vaquero, Alejandro

    2013-01-01

    In this paper, we discuss the vacuum structure of QCD with two flavors of Wilson fermions, inside the Aoki phase. We provide numerical evidence, coming from HMC simulations in 4 4 , 6 4 and 8 4 lattices, supporting a vacuum structure for this model at strong coupling more complex than the one assumed in the standard wisdom, with new vacua where the expectation value of iψ ¯ γ 5 ψ can take non-zero values, and which can not be connected with the Aoki vacua by parity–flavor symmetry transformations

  19. Integrating structural and mutagenesis data to elucidate GPCR ligand binding

    DEFF Research Database (Denmark)

    Munk, Christian; Harpsøe, Kasper; Hauser, Alexander S

    2016-01-01

    is reported that exhibit activity through multiple receptors, binding in allosteric sites, and bias towards different intracellular signalling pathways. Furthermore, a wealth of single point mutants has accumulated in literature and public databases. Integrating these structural and mutagenesis data will help...

  20. Collision-Induced Dissociation Mass Spectrometry: A Powerful Tool for Natural Product Structure Elucidation.

    Science.gov (United States)

    Johnson, Andrew R; Carlson, Erin E

    2015-11-03

    Mass spectrometry is a powerful tool in natural product structure elucidation, but our ability to directly correlate fragmentation spectra to these structures lags far behind similar efforts in peptide sequencing and proteomics. Often, manual data interpretation is required and our knowledge of the expected fragmentation patterns for many scaffolds is limited, further complicating analysis. Here, we summarize advances in natural product structure elucidation based upon the application of collision induced dissociation fragmentation mechanisms.

  1. Structure elucidation of chromogen resulting from jaffe's reaction

    International Nuclear Information System (INIS)

    Hussain, I.; Tariq, M.I.; Siddiqui, H.L.

    2009-01-01

    Jaffe's reaction is a reaction of creatinine with alkaline picric acid resulting in red chromogen. This color is being used widely for the estimation of creatinine in biological fluids without knowing the exact structure of the chromogen. The red species is isolated and its UV/Visible, /sup 1/H- and /sup 13/C- NMR studies are carried out. It is found that the red species is not a pure compound but a mixture of stereoisomers. Moreover, the red species in water reflects the same UV /Visible spectra as given by the reaction of creatinine with alkaline picrate in aqueous media The red species is a 2:3 molar Meisenheimer a-complex of creatinine-picric acid. (author)

  2. Chemical synthesis and structure elucidation of bovine κ-casein (1-44)

    International Nuclear Information System (INIS)

    Bansal, Paramjit S.; Grieve, Paul A.; Marschke, Ronald J.; Daly, Norelle L.; McGhie, Emily; Craik, David J.; Alewood, Paul F.

    2006-01-01

    The caseins (α s1 , α s2 , β, and κ) are phosphoproteins present in bovine milk that have been studied for over a century and whose structures remain obscure. Here we describe the chemical synthesis and structure elucidation of the N-terminal segment (1-44) of bovine κ-casein, the protein which maintains the micellar structure of the caseins. κ-Casein (1-44) was synthesised by highly optimised Boc solid-phase peptide chemistry and characterised by mass spectrometry. Structure elucidation was carried out by circular dichroism and nuclear magnetic resonance spectroscopy. CD analysis demonstrated that the segment was ill defined in aqueous medium but in 30% trifluoroethanol it exhibited considerable helical structure. Further, NMR analysis showed the presence of a helical segment containing 26 residues which extends from Pro 8 to Arg 34 . This is First report which demonstrates extensive secondary structure within the casein class of proteins

  3. NMR spectroscopy: structure elucidation of cycloelatanene A: a natural product case study.

    Science.gov (United States)

    Urban, Sylvia; Dias, Daniel Anthony

    2013-01-01

    The structure elucidation of new secondary metabolites derived from marine and terrestrial sources is frequently a challenging task. The hurdles include the ability to isolate stable secondary metabolites of sufficient purity that are often present in products that the compound may rapidly degrade during and/or after the isolation, due to sensitivity to light, air oxidation, and/or temperature. In this way, precautions need to be taken, as much as possible to avoid any such chemical inter-conversions and/or degradations. Immediately after purification, the next step is to rapidly acquire all analytical spectroscopic data in order to complete the characterization of the isolated secondary metabolite(s), prior to any possible decomposition. The final hurdle in this multiple step process, especially in the acquisition of the NMR spectroscopic and other analytical data (mass spectra, infrared and ultra-violet spectra, optical rotation, etc.), is to assemble the structural moieties/units in an effort to complete the structure elucidation. Often ambiguity with the elucidation of the final structure remains when structural fragments identified are difficult to piece together on the basis of the HMBC NMR correlations or when the relative configuration cannot be unequivocally identified on the basis of NOE NMR enhancements observed. Herein, we describe the methodology used to carry out the structure elucidation of a new C16 chamigrene, cycloelatanene A (5) which was isolated from the southern Australian marine alga Laurencia elata (Rhodomelaceae). The general approach and principles used in the structure determination of this compound can be applied to the structure elucidation of other small molecular weight compounds derived from either natural or synthetic sources.

  4. Structure Elucidation and Cytotoxic Evaluation of New Polyacetylenes from a Marine Sponge Petrosia sp.

    Directory of Open Access Journals (Sweden)

    Yung-Shun Juan

    2014-09-01

    Full Text Available The sponge Petrosia sp. yielded five polyacetylenic compounds (1–5, including two new polyacetylenes, petrosianynes A (1 and B (2. The structures of these compounds were elucidated by detailed spectroscopic analysis and by comparison with the physical and spectral data of related known analogues. Compounds 1–5 exhibited significant cytotoxic activity against a limited panel of cancer cell lines.

  5. Nature's Migraine Treatment: Isolation and Structure Elucidation of Parthenolide from "Tanacetum parthenium"

    Science.gov (United States)

    Walsh, Emma L.; Ashe, Siobhan; Walsh, John J.

    2012-01-01

    The purpose of this experiment is to provide students with the essential skills and knowledge required to perform the extraction, isolation, and structural elucidation of parthenolide from "Tanacetum parthenium" or feverfew. Students are introduced to a background of the traditional medicinal uses of parthenolide, while more modern applications of…

  6. Nature's Anti-Alzheimer's Drug: Isolation and Structure Elucidation of Galantamine from "Leucojum Aestivum"

    Science.gov (United States)

    Halpin, Catherine M.; Reilly, Ciara; Walsh, John J.

    2010-01-01

    The discovery that galantamine penetrates the blood-brain barrier has led to its clinical use in the treatment of choline-deficiency conditions in the brain, such as Alzheimer's disease. This experiment involves the isolation and structure elucidation of galantamine from "Leucojum aestivum". Isolation of the alkaloid constituents in "L. aestivum"…

  7. Catharanthus alkaloids XXXII: isolation of alkaloids from Catharanthus trichophyllus roots and structure elucidation of cathaphylline.

    Science.gov (United States)

    Cordell, G A; Farnsworth, N R

    1976-03-01

    Further examination of the cytotoxic alkaloid fractions of Catharanthus trichophyllus roots afforded nine alkaloids. Two of these alkaloids, lochnericine and horhammericine, are responsible for part of the cytotoxic activity. The structure elucidation of cathaphylline, a new beta-anilino acrylate derivative, is described.

  8. General scheme for elucidating the structure of organic compounds using spectroscopic and spectrometric methods

    International Nuclear Information System (INIS)

    Ribeiro, Carlos Magno R.; Souza, Nelson Angelo de

    2007-01-01

    This work describes a systematic method to be applied in undergraduate courses of organic chemistry, correlating infrared spectra, hydrogen and carbon-13 nuclear magnetic resonance, and mass spectra. To this end, a scheme and a table were developed to conduct the elucidation of the structure of organic compounds initially using infrared spectra. Interpretation of hydrogen and carbon-13 nuclear magnetic resonance spectra and of mass spectra is used to confirm the proposed structure. (author)

  9. Structural elucidation of an antibiotic from the fungus Fusarium avenaceum Fries Sacc.; an amended structure for lateropyrone

    International Nuclear Information System (INIS)

    Gorst-Allman, C.P.; Van Rooyen, P.H.; Wnuk, S.; Golinski, P.; Chelkowski, J.

    1986-01-01

    The structural elucidation by X-ray crystallography of an antibiotic produced by Fusarium avenaceum Fries Sacc. is described. Some chemical reactions of the metabolite are reported, and the identity of the metabolite with lateropyrone is proposed. The structure reported for lateropyrone is amended. 1 H n.m.r. and 13 C n.m.r. are used in this study

  10. Mass Spectra-Based Framework for Automated Structural Elucidation of Metabolome Data to Explore Phytochemical Diversity

    Science.gov (United States)

    Matsuda, Fumio; Nakabayashi, Ryo; Sawada, Yuji; Suzuki, Makoto; Hirai, Masami Y.; Kanaya, Shigehiko; Saito, Kazuki

    2011-01-01

    A novel framework for automated elucidation of metabolite structures in liquid chromatography–mass spectrometer metabolome data was constructed by integrating databases. High-resolution tandem mass spectra data automatically acquired from each metabolite signal were used for database searches. Three distinct databases, KNApSAcK, ReSpect, and the PRIMe standard compound database, were employed for the structural elucidation. The outputs were retrieved using the CAS metabolite identifier for identification and putative annotation. A simple metabolite ontology system was also introduced to attain putative characterization of the metabolite signals. The automated method was applied for the metabolome data sets obtained from the rosette leaves of 20 Arabidopsis accessions. Phenotypic variations in novel Arabidopsis metabolites among these accessions could be investigated using this method. PMID:22645535

  11. Mass spectra-based framework for automated structural elucidation of metabolome data to explore phytochemical diversity

    Directory of Open Access Journals (Sweden)

    Fumio eMatsuda

    2011-08-01

    Full Text Available A novel framework for automated elucidation of metabolite structures in liquid chromatography-mass spectrometer (LC-MS metabolome data was constructed by integrating databases. High-resolution tandem mass spectra data automatically acquired from each metabolite signal were used for database searches. Three distinct databases, KNApSAcK, ReSpect, and the PRIMe standard compound database, were employed for the structural elucidation. The outputs were retrieved using the CAS metabolite identifier for identification and putative annotation. A simple metabolite ontology system was also introduced to attain putative characterization of the metabolite signals. The automated method was applied for the metabolome data sets obtained from the rosette leaves of 20 Arabidopsis accessions. Phenotypic variations in novel Arabidopsis metabolites among these accessions could be investigated using this method.

  12. Isolation and Structural Elucidation of Chondrosterins F–H from the Marine Fungus Chondrostereum sp.

    Directory of Open Access Journals (Sweden)

    Wen-Jian Lan

    2013-02-01

    Full Text Available The marine fungus Chondrostereum sp. was collected from a soft coral of the species Sarcophyton tortuosum from the South China Sea. Three new compounds, chondrosterins F–H (1, 4 and 5, together with three known compounds, incarnal (2, arthrosporone (3, and (2E-decene-4,6,8-triyn-1-ol (6, were isolated. Their structures were elucidated primarily based on NMR and MS data. Incarnal (2 exhibited potent cytotoxic activity against various cancer cell lines.

  13. Isolation and Structure Elucidation of Three New Dolastanes from the Brown Alga Dilophus spiralis

    Directory of Open Access Journals (Sweden)

    Vassilios Roussis

    2013-04-01

    Full Text Available Three new dolastane diterpenes (1–3 and five previously reported perhydroazulenes were isolated from the organic extracts of the brown alga Dilophus spiralis. The structure elucidation and the assignment of the relative configurations of the isolated natural products were based on extensive analyses of their spectroscopic data, whereas the absolute configuration of metabolite 2 was determined through its chemical conversion to a previously isolated compound of known configuration.

  14. Structure elucidation of the new citharoxazole from the Mediterranean deep-sea sponge Latrunculia (Biannulata) citharistae.

    Science.gov (United States)

    Genta-Jouve, Grégory; Francezon, Nellie; Puissant, Alexandre; Auberger, Patrick; Vacelet, Jean; Pérez, Thierry; Fontana, Angelo; Mourabit, Ali Al; Thomas, Olivier P

    2011-08-01

    Citharoxazole (1), a new batzelline derivative featuring a benzoxazole moiety, was isolated from the Mediterranean deep-sea sponge Latrunculia (Biannulata) citharistae Vacelet, 1969, together with the known batzelline C (2). This is the first chemical study of a Mediterranean Latrunculia species and the benzoxazole moiety is unprecedented for this family of marine natural products. The structure was mainly elucidated by the interpretation of NMR spectra and especially HMBC correlations. Copyright © 2011 John Wiley & Sons, Ltd.

  15. The Crystal Structure of the Malaria Pigment Hemozoin as Elucidated by X-ray Powder Diffraction

    DEFF Research Database (Denmark)

    Straasø, Tine

    survival. Successful inhibition of hemozoin crystallization will lead to parasitic death and thus break the cycle. The aim of this thesis is to elucidate the structure of hemozoin by means of X-ray diffraction techniques. Knowledge of the structure will help facilitate intelligent drug design in the future....... As part of the project an all-in-vacuum powder diffractometer was developed, which provides data with a minimum background level and an improved signal-to-noise ratio. Moreover, the diffractometer is designed with the particular purpose of decreasing the number of parameters to be fitted. Installation...

  16. Computer-assisted methods for molecular structure elucidation: realizing a spectroscopist's dream

    Directory of Open Access Journals (Sweden)

    Elyashberg Mikhail

    2009-03-01

    Full Text Available Abstract Background This article coincides with the 40 year anniversary of the first published works devoted to the creation of algorithms for computer-aided structure elucidation (CASE. The general principles on which CASE methods are based will be reviewed and the present state of the art in this field will be described using, as an example, the expert system Structure Elucidator. Results The developers of CASE systems have been forced to overcome many obstacles hindering the development of a software application capable of drastically reducing the time and effort required to determine the structures of newly isolated organic compounds. Large complex molecules of up to 100 or more skeletal atoms with topological peculiarity can be quickly identified using the expert system Structure Elucidator based on spectral data. Logical analysis of 2D NMR data frequently allows for the detection of the presence of COSY and HMBC correlations of "nonstandard" length. Fuzzy structure generation provides a possibility to obtain the correct solution even in those cases when an unknown number of nonstandard correlations of unknown length are present in the spectra. The relative stereochemistry of big rigid molecules containing many stereocenters can be determined using the StrucEluc system and NOESY/ROESY 2D NMR data for this purpose. Conclusion The StrucEluc system continues to be developed in order to expand the general applicability, provide improved workflows, usability of the system and increased reliability of the results. It is expected that expert systems similar to that described in this paper will receive increasing acceptance in the next decade and will ultimately be integrated directly to analytical instruments for the purpose of organic analysis. Work in this direction is in progress. In spite of the fact that many difficulties have already been overcome to deliver on the spectroscopist's dream of "fully automated structure elucidation" there is

  17. APPLICATION OF A C-13 NMR TOPOLOGICAL MODEL TO THE STRUCTURE ELUCIDATION OF ORGANIC COMPOUNDS

    Institute of Scientific and Technical Information of China (English)

    袁身刚; 彭琛; 郑崇直

    1992-01-01

    This paper presents an approach which can elucidate automatically the structures of simple organic compounds from their C-13 NMR spectral data by using a computer. Based on a substructure/C-13 NMR chemical shift topological correlation model, the approach deduces the candidate substructures and the constraints for the substructure assembling from the molecular formula and C-13 NMR spectral data. Then, candidate structures are generated under these constraints by assembling the candidate substructures in a partial superposition manner. Candidate substructures or structures are evaluated once they are generated in order to eliminate those conflicting with the original data as early as possible. The evaluation of a (sub)structure is mainly carried out by simulating its C-13 NMR (sub) spectrum, which is again based on the model, and comparing the simulated spectrum with the original data.

  18. Tannin structural elucidation and quantitative ³¹P NMR analysis. 1. Model compounds.

    Science.gov (United States)

    Melone, Federica; Saladino, Raffaele; Lange, Heiko; Crestini, Claudia

    2013-10-02

    Tannins and flavonoids are secondary metabolites of plants that display a wide array of biological activities. This peculiarity is related to the inhibition of extracellular enzymes that occurs through the complexation of peptides by tannins. Not only the nature of these interactions, but more fundamentally also the structure of these heterogeneous polyphenolic molecules are not completely clear. This first paper describes the development of a new analytical method for the structural characterization of tannins on the basis of tannin model compounds employing an in situ labeling of all labile H groups (aliphatic OH, phenolic OH, and carboxylic acids) with a phosphorus reagent. The ³¹P NMR analysis of ³¹P-labeled samples allowed the unprecedented quantitative and qualitative structural characterization of hydrolyzable tannins, proanthocyanidins, and catechin tannin model compounds, forming the foundations for the quantitative structural elucidation of a variety of actual tannin samples described in part 2 of this series.

  19. Dihydronaflavonols from the leaves of Derris urucu (Leguminosae): structural elucidation and DPPH radical-scavenging activity

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, Livia T.; Silva, Geilson A. da; Ferreira, Malisson; Silva, Milton N. da; Santos, Alberdan S.; Arruda, Alberto C.; Guilhon, Gisele M.S.P.; Santos, Lourivaldo S.; Arruda, Mara Silvia P. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Ciencias Exatas e Naturais. Programa de Pos-Graduacao em Quimica], e-mail: mspa@ufpa.br; Borges, Rosilvaldo dos Santos [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Fac. de Farmacia. Inst. de Ciencias

    2009-07-01

    Derris urucu is an Amazonian plant with insecticide and ichthyotoxic properties. Studies with this species show the presence of flavonoids, mainly rotenoids, as well as stilbenes. The ethanol extract of the leaves of Derris urucu (Leguminosae) afforded three new dihydroflavonols named urucuol A (1), B (2) and C (3), and the dihydroflavonol isotirumalin (4). Their structures were elucidated by extensive analysis of 1D and 2D NMR, UV and IR spectra and MS data and comparison with literature data. The isolated compounds (1-4) were evaluated for DPPH radical scavenging activity and showed a relatively lower antioxidant ability compared to the commercial antioxidant trans-resveratrol. (author)

  20. Isolation and structure elucidation of the nucleoside antibiotic strepturidin from Streptomyces albus DSM 40763.

    Science.gov (United States)

    Pesic, Alexander; Steinhaus, Britta; Kemper, Sebastian; Nachtigall, Jonny; Kutzner, Hans Jürgen; Höfle, Gerhard; Süssmuth, Roderich D

    2014-06-01

    The antibiotic strepturidin (1) was isolated from the microorganism Streptomyces albus DSM 40763, and its structure elucidated by spectroscopic methods and chemical degradation studies. The determination of the relative and absolute stereocenters was partially achieved using chiral GC/EI-MS analysis and microderivatization by acetal ring formation and subsequent 2D-NMR analysis of key (1)H,(1)H-NOESY NMR correlations and extraction of (1)H,(13)C coupling constants from (1)H,(13)C-HMBC NMR spectra. Based on these results, a biosynthesis model was proposed.

  1. Isolation and Structural Elucidation of an Unknown compound from Murraya alternans (Kurz)Swingle

    International Nuclear Information System (INIS)

    Mya Aye; Hla Myoe Min; Sein Htun

    2002-02-01

    A new taxon of a species, Murraya alternans (Kurz) Swingle (Myanmar name, Naganaing) the series of Murraya belonging to the family Rutaceae had been recognized by Peter G. Waterman in 1986. However, this species has not been undertaken in botanical, medical, and chemical aspects. In this paper, scientific study on this taxon was chemically carried out for the first time. One of the unknown compounds was isolated from this species by column and high performance liquid chromatographic methods. It's partial structure could also be elucidated by spectral analysis such as IR, MS, H NMR(400MHz), C NMR (100MHz) spectrometry respectively. (author)

  2. Isolation and structural elucidation of secondary metabolites of plants of the families asteraceae and urticaceae

    International Nuclear Information System (INIS)

    Villagra Quesada, E.

    2002-01-01

    A phytochemistry study of plant's species of the Asteraceae and Urticaceae family is proposed in order to isolate and to elucidate the structure of active principles; due to the fact that several studies have found that some of these families have compounds with anti-inflammatory activity, mainly lactonas sesquiterpenicas . The phytochemistry study was carried out through the application of chromatography techniques, for the separation and purification of the compounds. Includes chromatography of column, fine and liquid layer of high resolution. On the other hand, spectroscopic techniques were used for the elucidation, mainly of nuclear magnetic resonance (RMN) as much of one as of two dimensions. In this way, it was possible to isolate 14 compounds in Decachaeta thieleana and 10 in Phenax mexicanus, from which 6 correspond compounds of innovative structure. The comparison of the results obtained in Decachaeta thieleana (with previous studies) evidences that specimens, orphologically identical (the same species, but different locations), possess totally different compounds. This suggests that the studied specimens do not correspond to the same species. However, the determination of such a cause not only evade the objectives of this work but also the area of study of Chemistry [es

  3. Structure Elucidation of Unknown Metabolites in Metabolomics by Combined NMR and MS/MS Prediction.

    Science.gov (United States)

    Boiteau, Rene M; Hoyt, David W; Nicora, Carrie D; Kinmonth-Schultz, Hannah A; Ward, Joy K; Bingol, Kerem

    2018-01-17

    We introduce a cheminformatics approach that combines highly selective and orthogonal structure elucidation parameters; accurate mass, MS/MS (MS²), and NMR into a single analysis platform to accurately identify unknown metabolites in untargeted studies. The approach starts with an unknown LC-MS feature, and then combines the experimental MS/MS and NMR information of the unknown to effectively filter out the false positive candidate structures based on their predicted MS/MS and NMR spectra. We demonstrate the approach on a model mixture, and then we identify an uncatalogued secondary metabolite in Arabidopsis thaliana . The NMR/MS² approach is well suited to the discovery of new metabolites in plant extracts, microbes, soils, dissolved organic matter, food extracts, biofuels, and biomedical samples, facilitating the identification of metabolites that are not present in experimental NMR and MS metabolomics databases.

  4. Streamlined structure elucidation of an unknown compound in a pigment formulation.

    Science.gov (United States)

    Yüce, Imanuel; Morlock, Gertrud E

    2016-10-21

    A fast and reliable quality control is important for ink manufacturers to ensure a constant production grade of mixtures and chemical formulations, and unknown components attract their attention. Structure elucidating techniques seem time-consuming in combination with column-based methods, but especially the low solubility of pigment formulations is challenging the analysis. In contrast, layer chromatography is more tolerant with regard to pigment particles. One PLC plate for NMR and FTIR analyses and one HPTLC plate for recording of high resolution mass spectra, MS/MS spectra and for gathering information on polarity and spectral properties were needed to characterize a structure, exemplarily shown for an unknown component in pigment Red 57:1 to be 3-hydroxy-2-naphtoic acid. A preparative layer chromatography (PLC) workflow was developed that used an Automated Multiple Development 2 (AMD 2) system. The 0.5-mm PLC plate could still be operated in the AMD 2 system and allowed a smooth switch from the analytical to the preparative gradient separation. Through automated gradient development and the resulting focusing of bands, the sharpness of the PLC bands was improved. For NMR, the necessary high load of the target compound on the PLC plate was achieved via a selective solvent extraction that discriminated the polar sample matrix and thus increased the application volume of the extract that could maximally be applied without overloading. By doing so, the yield for NMR analysis was improved by a factor of 9. The effectivity gain through a simple, but thoroughly chosen extraction solvent is often overlooked, and for educational purpose, it was clearly illustrated and demonstrated by an extended solvent screening. Thus, PLC using an automated gradient development after a selective extraction was proven to be a new powerful combination for structural elucidation by NMR. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Comprehensive secondary structure elucidation of four genera of the family Pospiviroidae.

    Directory of Open Access Journals (Sweden)

    Tamara Giguère

    Full Text Available Viroids are small, circular, single stranded RNA molecules that infect plants. Since they are non-coding, their structures play a critical role in their life cycles. To date, little effort has been spend on elucidating viroid structures in solution due to both the experimental difficulties and the time-consuming nature of the methodologies implicated. Recently, the technique of high-throughput selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE was adapted for the probing of the members of family Avsunviroidae, all of whom replicate in the chloroplast and demonstrate ribozyme activity. In the present work, twelve viroid species belonging to four different genera of the family Pospiviroidae, whose members are characterized by the presence of a central conserved region (CCR and who replicate in nucleus of the host, were probed. Given that the structures of five distinct viroid species from the family Pospiviroidae have been previously reported, an overview of the different structural characteristics for all genera and the beginning of a manual classification of the different viroids based on their structural features are presented here.

  6. Structure elucidation of a flavonoid glycoside from the roots of Clerodendrum serratum (L. Moon, Lamiaceae

    Directory of Open Access Journals (Sweden)

    S. S. Bhujbal

    2010-12-01

    Full Text Available Apigenin-7-glucoside, C21H20O10 (7-(β-D-glucopyranosyloxy-5-hydroxy-2-(4-hydroxyphenyl-4H-1-benzopyran-4-one, was first time isolated from the roots of Clerodendrum serratum (L. Moon, Lamiaceae. Structure elucidation of the compound was carried out by ¹H NMR and FAB-MS studies.Apigenin-7-glucosídeo, C21H20O10 (7-(β-D-glucopiranosiloxi-5-hidroxi-2-(4-hidroxifenil-4H-1-benzopiran-4-ona, foi isolado pela primeira vez das raízes de Clerodendrum serratum (L. Moon, Lamiaceae. A elucidação estrutural da susbtância foi feita através de estudos de ¹H NMR e FAB-MS.

  7. Structure elucidation and immunomodulatory activity of a beta glucan from the fruiting bodies of Ganoderma sinense.

    Directory of Open Access Journals (Sweden)

    Xiao-Qiang Han

    Full Text Available A polysaccharide named GSP-2 with a molecular size of 32 kDa was isolated from the fruiting bodies of Ganoderma sinense. Its structure was well elucidated, by a combined utilization of chemical and spectroscopic techniques, to be a β-glucan with a backbone of (1→4- and (1→6-Glcp, bearing terminal- and (1→3-Glcp side-chains at O-3 position of (1→6-Glcp. Immunological assay exhibited that GSP-2 significantly induced the proliferation of BALB/c mice splenocytes with target on only B cells, and enhanced the production of several cytokines in human peripheral blood mononuclear cells and derived dendritic cells. Besides, the fluorescent labeled GSP-2 was phagocytosed by the RAW 264.7 cells and induced the nitric oxide secretion from the cells.

  8. Dynamical structure analysis of crystalline-state reaction and elucidation of chemical reactivity in crystalline environment

    International Nuclear Information System (INIS)

    Ohashi, Yuji

    2010-01-01

    It was found that a chiral alkyl group bonded to the cobalt atom in a cobalt complex crystal was racemized with retention of the single crystal form on exposure to visible light. Such reactions, which are called crystalline-state reactions, have been found in a variety of cobalt complex crystals. The concept of reaction cavity was introduced to explain the reaction rate quantitatively and the chirality of the photo-product. The new diffractometers and detectors were made for rapid data collection. The reaction mechanism was also elucidated using neutron diffraction analysis. The unstable reaction intermediates were analyzed using cryo-trapping method. The excited-state structures were obtained at the equilibrium state between ground and excited states. (author)

  9. Structure Elucidation and Immunomodulatory Activity of A Beta Glucan from the Fruiting Bodies of Ganoderma sinense

    Science.gov (United States)

    Yue, Rui-Qi; Dong, Cai-Xia; Chan, Chung-Lap; Ko, Chun-Hay; Cheung, Wing-Shing; Luo, Ke-Wang; Dai, Hui; Wong, Chun-Kwok; Leung, Ping-Chung; Han, Quan-Bin

    2014-01-01

    A polysaccharide named GSP-2 with a molecular size of 32 kDa was isolated from the fruiting bodies of Ganoderma sinense. Its structure was well elucidated, by a combined utilization of chemical and spectroscopic techniques, to be a β-glucan with a backbone of (1→4)– and (1→6)–Glcp, bearing terminal- and (1→3)–Glcp side-chains at O-3 position of (1→6)–Glcp. Immunological assay exhibited that GSP-2 significantly induced the proliferation of BALB/c mice splenocytes with target on only B cells, and enhanced the production of several cytokines in human peripheral blood mononuclear cells and derived dendritic cells. Besides, the fluorescent labeled GSP-2 was phagocytosed by the RAW 264.7 cells and induced the nitric oxide secretion from the cells. PMID:25014571

  10. Isolation and structural elucidation of tiamulin metabolites formed in liver microsomes of pigs.

    Science.gov (United States)

    Lykkeberg, Anne Kruse; Cornett, Claus; Halling-Sørensen, Bent; Hansen, Steen Honoré

    2006-09-18

    Although the antimicrobial tiamulin is extensively metabolized in pigs, the metabolism is not well investigated. In this work the NADPH dependent metabolism of tiamulin in liver microsomes from pigs has been studied. The tiamulin metabolites formed in the incubations were analysed using LC-MS, and three major metabolites were isolated using solid phase extraction and preparative HPLC. The final structure elucidations were performed by tandem mass spectrometry and (1)H and (13)C NMR. The structures of the metabolites were found to be 2beta-hydroxy-tiamulin, 8alpha-hydroxy-tiamulin and N-deethyl-tiamulin. In addition, the LC-MS chromatograms revealed two other minor metabolites. From their chromatography and from MS(2) analysis the structures were estimated to be 2beta-hydroxy-N-deethyl-tiamulin and 8alpha-hydroxy-N-deethyl-tiamulin, but the structures were not confirmed by NMR. In these studies approximately 20% of tiamulin was deethylated, 10% was hydroxylated in the 2beta-position and 7% was hydroxylated in the 8alpha-position. About 40% of tiamulin was metabolized during the incubation conditions used. The protein precipitation in the incubations was performed using perchloric acid, and the preparative purification was performed under alkaline conditions. Therefore, the stability of the metabolites under these conditions was studied. The metabolites were found to be stable in the acid solution, but under alkaline conditions, particularly at room temperature, the stability of especially 8alpha-hydroxy-tiamulin was considerably reduced (40% loss after 1 week).

  11. Elucidation of Peptide-Directed Palladium Surface Structure for Biologically Tunable Nanocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Nicholas M.; Ramezani-Dakhel, Hadi; Slocik, Joseph M.; Briggs, Beverly D.; Ren, Yang; Frenkel, Anatoly I.; Petkov, Valeri; Heinz, Hendrik; Naik, Rajesh R.; Knecht, Mark R.

    2015-05-01

    Peptide-enabled synthesis of inorganic nanostructures represents an avenue to access catalytic materials with tunable and optimized properties. This is achieved via peptide complexity and programmability that is missing in traditional ligands for catalytic nanomaterials. Unfortunately, there is limited information available to correlate peptide sequence to particle structure and catalytic activity to date. As such, the application of peptide-enabled nanocatalysts remains limited to trial and error approaches. In this paper, a hybrid experimental and computational approach is introduced to systematically elucidate biomolecule-dependent structure/function relationships for peptide-capped Pd nanocatalysts. Synchrotron X-ray techniques were used to uncover substantial particle surface structural disorder, which was dependent upon the amino acid sequence of the peptide capping ligand. Nanocatalyst configurations were then determined directly from experimental data using reverse Monte Carlo methods and further refined using molecular dynamics simulation, obtaining thermodynamically stable peptide-Pd nanoparticle configurations. Sequence-dependent catalytic property differences for C-C coupling and olefin hydrogenation were then eluddated by identification of the catalytic active sites at the atomic level and quantitative prediction of relative reaction rates. This hybrid methodology provides a clear route to determine peptide-dependent structure/function relationships, enabling the generation of guidelines for catalyst design through rational tailoring of peptide sequences

  12. Structure elucidation of metabolite x17299 by interpretation of mass spectrometric data.

    Science.gov (United States)

    Zhang, Qibo; Ford, Lisa A; Evans, Anne M; Toal, Douglas R

    2017-01-01

    A major bottleneck in metabolomic studies is metabolite identification from accurate mass spectrometric data. Metabolite x17299 was identified in plasma as an unknown in a metabolomic study using a compound-centric approach where the associated ion features of the compound were used to determine the true molecular mass. The aim of this work is to elucidate the chemical structure of x17299, a new compound by de novo interpretation of mass spectrometric data. An Orbitrap Elite mass spectrometer was used for acquisition of mass spectra up to MS 4 at high resolution. Synthetic standards of N,N,N -trimethyl-l-alanyl-l-proline betaine (l,l-TMAP), a diastereomer, and an enantiomer were chemically prepared. The planar structure of x17299 was successfully proposed by de novo mechanistic interpretation of mass spectrometric data without any laborious purification and nuclear magnetic resonance spectroscopic analysis. The proposed structure was verified by deuterium exchanged mass spectrometric analysis and confirmed by comparison to a synthetic standard. Relative configuration of x17299 was determined by direct chromatographic comparison to a pair of synthetic diastereomers. Absolute configuration was assigned after derivatization of x17299 with a chiral auxiliary group followed by its chromatographic comparison to a pair of synthetic standards. The chemical structure of metabolite x17299 was determined to be l,l-TMAP.

  13. Structural Elucidation of Novel Saponins in the Sea Cucumber Holothuria lessoni

    Science.gov (United States)

    Bahrami, Yadollah; Zhang, Wei; Chataway, Tim; Franco, Chris

    2014-01-01

    Sea cucumbers are prolific producers of a wide range of bioactive compounds. This study aimed to purify and characterize one class of compound, the saponins, from the viscera of the Australian sea cucumber Holothuria lessoni. The saponins were obtained by ethanolic extraction of the viscera and enriched by a liquid-liquid partition process and adsorption column chromatography. A high performance centrifugal partition chromatography (HPCPC) was applied to the saponin-enriched mixture to obtain saponins with high purity. The resultant purified saponins were profiled using MALDI-MS/MS and ESI-MS/MS which revealed the structure of isomeric saponins to contain multiple aglycones and/or sugar residues. We have elucidated the structure of five novel saponins, Holothurins D/E and Holothurinosides X/Y/Z, along with seven reported triterpene glycosides, including sulfated and non-sulfated saponins containing a range of aglycones and sugar moieties, from the viscera of H. lessoni. The abundance of novel compounds from this species holds promise for biotechnological applications. PMID:25110919

  14. Elucidation of structural isomers from the homogeneous rhodium-catalyzed isomerization of vegetable oils.

    Science.gov (United States)

    Andjelkovic, Dejan D; Min, Byungrok; Ahn, Dong; Larock, Richard C

    2006-12-13

    The structural isomers formed by the homogeneous rhodium-catalyzed isomerization of several vegetable oils have been elucidated. A detailed study of the isomerization of the model compound methyl linoleate has been performed to correlate the distribution of conjugated isomers, the reaction kinetics, and the mechanism of the reaction. It has been shown that [RhCl(C8H8)2]2 is a highly efficient and selective isomerization catalyst for the production of highly conjugated vegetable oils with a high conjugated linoleic acid (CLA) content, which is highly desirable in the food industry. The combined fraction of the two major CLA isomers [(9Z,11E)-CLA and (10E,12Z)-CLA] in the overall CLA mixture is in the range from 76.2% to 93.4%. The high efficiency and selectivity of this isomerization method along with the straightforward purification process render this approach highly promising for the preparation of conjugated oils and CLA. Proposed improvements in catalyst recovery and reusability will only make this method more appealing to the food, paint, coating, and polymer industries in the future.

  15. DFT and EXAFS, mutually enhancing tools for structure elucidation of Tc complexes

    International Nuclear Information System (INIS)

    Breynaert, E.; Bruggeman, C.; Maes, A.

    2005-01-01

    Full text of publication follows: The redox-sensitive fission product technetium-99 (Tc) is of great interest in nuclear waste disposal studies because of its potential for contaminating the geosphere due to its very long half-life (2.13 x 10 5 year) and high mobility under oxidising conditions, where technetium forms pertechnetate (TcO 4 - ). Under suitable reducing conditions, e.g. in the presence of an iron(II) containing solid phase which can act as an electron donor, the solubility can be limited by the reduction of pertechnetate followed by the formation of a surface precipitate [1]. However, by association with mobile humic substances (HS) or other associating/complexing species, the solubility of reduced Tc species may be drastically enhanced [2]. The elucidation of the identity and geometrical structure of the species causing this enhanced solubility often remains a difficult issue. Extended X-Ray Absorption Fluorescence Spectroscopy/ X-Ray Absorption Near Edge Spectroscopy (EXAFS/XANES) analysis can be very helpful to determine the molecular surroundings of reduced Tc organic complexes of Tc(IV) colloid-HS-associations. The interpretation of the EXAFS spectra is however not a straightforward process due to the possibly strong influence of multiple scattering paths on the spectra. Contrary to single scattering analysis which can be easily performed on the experimental EXAFS spectra, multiple scattering analysis can only be done, based on good approximations of the possible geometrical structures of the species under consideration. It has been shown that the Density Functional Theory (DFT) can be used to perform geometry optimizations of technetium species and therefore can be utilized to predict the structure of technetium complexes [3]. The success and computational effort needed for such structure predictions are however highly dependant on the quality of the initial structure from which the geometry optimization is started. Single scattering analysis of

  16. Clinical evaluation of thyrotropin-releasing hormone (TRH) test with a sensitive immunoradiometric thyrotropin (TSH) assay kit

    International Nuclear Information System (INIS)

    Nakamura, Saeko; Demura, Reiko; Yamanaka, Yukako; Ishiwatari, Naoko; Jibiki, Kazuko; Odagiri, Emi; Demura, Hiroshi

    1987-01-01

    Thyrotropin-releasing hormone (TRH) test was performed using a commercially available immunoradiometric thyrotropin (TSH) assay kit (RIA-gnost hTSH) in patients with endocrine diseases. The basal serum concentration of TSH ranged from 0.2 to 2.9 μU/ml in healthy subjects. The values for endocrine diseases, except for Graves' disease, were almost within the normal range. A significant increase in TSH values caused by TRH test was observed in females compared with males (4.4 - 24.7 μU/ml vs 4.1 - 12.3 μU/ml). In cases of Graves' disease, there was a good correlation between the basal TSH value and the response of TSH to TRH. However, in the other endocrine diseases, including acromegaly, prolactinoma, anorexia nervosa, Cushing syndrome, and hypopituitarism, the response of TSH to TRH did not necessarily correlated with the basal TSH value. TRH test would be of value in elucidating pathophysiologic features, as well as in accurately diagnosing secretion reserve of TSH. (Namekawa, K.)

  17. Clinical evaluation of thyrotropin-releasing hormone (TRH) test with a sensitive immunoradiometric thyrotropin (TSH) assay kit

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Saeko; Demura, Reiko; Yamanaka, Yukako; Ishiwatari, Naoko; Jibiki, Kazuko; Odagiri, Emi; Demura, Hiroshi

    1987-10-01

    Thyrotropin-releasing hormone (TRH) test was performed using a commercially available immunoradiometric thyrotropin (TSH) assay kit (RIA-gnost hTSH) in patients with endocrine diseases. The basal serum concentration of TSH ranged from 0.2 to 2.9 ..mu..U/ml in healthy subjects. The values for endocrine diseases, except for Graves' disease, were almost within the normal range. A significant increase in TSH values caused by TRH test was observed in females compared with males (4.4 - 24.7 ..mu..U/ml vs 4.1 - 12.3 ..mu..U/ml). In cases of Graves' disease, there was a good correlation between the basal TSH value and the response of TSH to TRH. However, in the other endocrine diseases, including acromegaly, prolactinoma, anorexia nervosa, Cushing syndrome, and hypopituitarism, the response of TSH to TRH did not necessarily correlated with the basal TSH value. TRH test would be of value in elucidating pathophysiologic features, as well as in accurately diagnosing secretion reserve of TSH. (Namekawa, K.).

  18. Production of specific-structured lipids by enzymatic interesterification: elucidation of acyl migration by response surface design

    DEFF Research Database (Denmark)

    Xu, Xuebing; Skands, Anja; Høy, Carl-Erik

    1998-01-01

    Production of specific-structured lipids (SSL) by lipase-catalyzed interesterification has been attracting more and more attention recently. However, it was found that acyl migration occurs during the reaction and causes the production of by-products. In this paper, the elucidation of acyl...

  19. pH-Controlled Oxidation of an Aromatic Ketone: Structural Elucidation of the Products of Two Green Chemical Reactions

    Science.gov (United States)

    Ballard, C. Eric

    2010-01-01

    A laboratory experiment emphasizing the structural elucidation of organic compounds has been developed as a discovery exercise. The "unknown" compounds are the products of the pH-controlled oxidation of 4'-methoxyacetophenone with bleach. The chemoselectivity of this reaction is highly dependent on the pH of the reaction media: under basic…

  20. Isolation and structure elucidation of an interaction product of aminotadalafil found in an illegal health food product.

    Science.gov (United States)

    Häberli, Adrian; Girard, Philippe; Low, Min-Yong; Ge, Xiaowei

    2010-09-21

    An interaction product of aminotadalafil was isolated from an illegal health food product. The structure of the interaction product was elucidated by means of IR, NMR, and mass spectroscopy. The hitherto unknown compound was characterized as condensation product of aminotadalafil and hydroxymethylfuraldehyde and is probably the result of a drug-excipient incompatibility. Copyright 2010. Published by Elsevier B.V.

  1. Flavonoid glycosides from Olax mannii: Structure elucidation and effect on the nuclear factor kappa B pathway.

    Science.gov (United States)

    Okoye, Festus B C; Sawadogo, Wamtinga Richard; Sendker, Jandirk; Aly, Amal H; Quandt, Bettina; Wray, Victor; Hensel, Andreas; Esimone, Charles O; Debbab, Abdessamad; Diederich, Marc; Proksch, Peter

    2015-12-24

    Olax mannii Oliv. (Olacaceae) is among the many medicinal plants used in Nigeria for the ethnomedicinal management of both cancer and inflammation. Such plants represent potential sources of innovative therapeutic agents for the treatment of cancer and other malignant disorders. While the majority of medicinal plants exert their anticancer effects by direct cytotoxicity on tumor cells, it is important that other mechanisms through which these plants can exhibit anticancer effects are investigated. Preliminary studies indicated that Olax mannii leaves are rich sources of novel flavonoid glycosides. The detailed chemistry as well the mechanisms through which these flavonoid constituents may exert their cancer chemo-preventive and therapeutic effects are, however, not yet investigated. The aim of this study is to carry out a detailed chemical investigation of Olax mannii leaves and the effects of the isolated constituents on the nuclear factor kappa B (NF-κB) pathway. A methanol leaf extract was subjected to various chromatographic separations to achieve isolation of flavonoid glycosides and the structures of the isolated compounds were elucidated by a combination of 1D and 2D NMR and high resolution mass spectrometry. Biological activities were assessed by measurement of cellular viability and proliferation using quantitative IncuCyte videomicroscopy, trypan blue staining and by quantification of the number of metabolically active K562 cells based on quantitation of ATP. The effect of the compounds on the inhibition of the NF-κB pathway as well as toxicity towards peripheral blood mononuclear cells to evaluate differential toxicity was also assayed. Chemical investigation of the methanol leaf extract of the plant material led to the isolation of three new flavonoid triglycosides, kaempferol 3-O-[α-D-apiofuranosyl-(1 → 2)-α-L-arabinofuranoside]-7-O-α-L-rhamnopyranoside (1), kaempferol 3-O-[β-D-glucopyranosyl-(1 → 2)-α-L-arabinofuranoside]-7-O

  2. Isolation and structural elucidation of secondary metabolites from plants of the Rutaceae family, Rubiaceae, Euphorbiaceae and Salicaceae

    International Nuclear Information System (INIS)

    Calderon Castro, Carlos

    2014-01-01

    A phytochemical study was conducted of the Zuelania guidonia plants (Salicaceae), croton ovalifolius (Euphorbiaceae) erythrochiton gymnanthus (Rutaceae) and Faramea occidentalis (Rubiaceae). Purification of the compounds was carried out using chromatographic techniques while structural elucidation was performed by experiments using nuclear magnetic resonance (NMR) and mass spectrometry (MS). Of Z. guidonia has been possible the purification and structural elucidation of 22 compounds (Z1-Z22), two labdane type diterpenes and 20 clerodane-type diterpenes. The clerodanes have presented 16 innovative structure, highlighting the presence of a group of 3,6-dihydro -1.2-dioxin and xylose group in some of them. In addition, 11 of the clerodanes were evaluated with cytotoxicity assays in three cancer cell lines CCRF-CEM (acute lymphoblastic leukemia), CEM-ADR5000 (acute lymphoblastic leukemia resistant to doxorubicin) MIA-Paca-2 (metastatic pancreas) and a line of healthy cells PBMC (peripheral blood mononuclear cells). The Z4, Z6 and Z15 compounds stood out as the most cytotoxic, particularly against CCRF-CEM cells with IC 50 values between 1.6 and 2.5 μM. Seven compounds identified as glutarimide alkaloids (C1-C7) were isolated and elucidated, five of which have presented a novel structure from C. ovalifolius. Three compounds (E1-E3) that are triterpenes derivatives of known structure sitosterol, were isolated and elucidated from E. gymnanthus plant. From F. occidentalis was obtained the structure of a pure compound (F1], which is a flavonoid of known structure. (author) [es

  3. Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis

    Directory of Open Access Journals (Sweden)

    Zheng Yang

    2016-02-01

    Full Text Available Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3, were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473, one of important cancer drugs target.

  4. The fundamentals behind solving for unknown molecular structures using computer-assisted structure elucidation: a free software package at the undergraduate and graduate levels.

    Science.gov (United States)

    Moser, Arvin; Pautler, Brent G

    2016-05-15

    The successful elucidation of an unknown compound's molecular structure often requires an analyst with profound knowledge and experience of advanced spectroscopic techniques, such as Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry. The implementation of Computer-Assisted Structure Elucidation (CASE) software in solving for unknown structures, such as isolated natural products and/or reaction impurities, can serve both as elucidation and teaching tools. As such, the introduction of CASE software with 112 exercises to train students in conjunction with the traditional pen and paper approach will strengthen their overall understanding of solving unknowns and explore of various structural end points to determine the validity of the results quickly. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Structure of E. coli 16S RNA elucidated by psoralen crosslinking

    International Nuclear Information System (INIS)

    Thompson, J.F.; Hearst, J.E.

    1983-01-01

    E. coli 16S RNA in solution was photoreacted with hydroxymethyltrimethylpsoralen and long wave ultraviolet light. Positions of crosslinks were determined to high resolution by partially digesting the RNA with T 1 RNase, separating the crosslinked fragments by two-dimensional gel electrophoresis, reversing the crosslink, and sequencing the separated fragments. This method yielded the locations of crosslinks to +/-15 nucleotides. Even finer placement has been made on the basis of our knowledge of psoralen reactivity. Thirteen unique crosslinks were mapped. Seven crosslinks confirmed regions of secondary structure which had been predicted in published phylogenetic models, three crosslinks discriminated between phylogenetic models, and three proved the existence of new structures. The new structures were all long-range interactions which appear to be in dynamic equilibrium with local secondary structure. Because this technique yields direct information about the secondary structure of large RNAs, it should prove invaluable in studying the structure of other RNAs of all sizes

  6. Bioactive Structure of Membrane Lipids and Natural Products Elucidated by a Chemistry-Based Approach.

    Science.gov (United States)

    Murata, Michio; Sugiyama, Shigeru; Matsuoka, Shigeru; Matsumori, Nobuaki

    2015-08-01

    Determining the bioactive structure of membrane lipids is a new concept, which aims to examine the functions of lipids with respect to their three-dimensional structures. As lipids are dynamic by nature, their "structure" does not refer solely to a static picture but also to the local and global motions of the lipid molecules. We consider that interactions with lipids, which are completely defined by their structures, are controlled by the chemical, functional, and conformational matching between lipids and between lipid and protein. In this review, we describe recent advances in understanding the bioactive structures of membrane lipids bound to proteins and related molecules, including some of our recent results. By examining recent works on lipid-raft-related molecules, lipid-protein interactions, and membrane-active natural products, we discuss current perspectives on membrane structural biology. © 2015 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Expert systems for structure elucidation of organic molecules by spectral methods

    International Nuclear Information System (INIS)

    Elyashberg, Mikhail E

    1999-01-01

    The state-of-the-art of the investigations aimed at creating expert systems for establishing the structure of organic molecules from IR, 1 H and 13 C NMR spectra is analysed. Computer methods used for identification of molecular fragments, generation of their structure and spectra prediction are considered. Principles of the creation of modern expert systems and general strategy of solving structural problems are discussed. The bibliography includes 174 references.

  8. Elucidation of the Structure Formation of Polymer-Conjugated Proteins in Solution and Block Copolymer Templates

    Science.gov (United States)

    Ferebee, Rachel L.

    The broader technical objective of this work is to contribute to the development of enzyme-functionalized nanoporous membranes that can function as autonomous and target selective dynamic separators. The scientific objective of the research performed within this thesis is to elucidate the parameters that control the mixing of proteins in organic host materials and in block copolymers templates in particular. A "biomimetic" membrane system that uses enzymes to selectively neutralize targets and trigger a change in permeability of nanopores lined with a pH-responsive polymer has been fabricated and characterized. Mechanical and functional stability, as well as scalability, have been demonstrated for this system. Additional research has focused on the role of polymeric ligands on the solubility characteristics of the model protein, Bovine Serum Albumin (BSA). For this purpose BSA was conjugated with poly(ethylene glycol) (PEG) ligands of varied degree of polymerization and grafting density. Combined static and dynamic light scattering was used (in conjunction with MALDI-TOF) to determine the second virial coefficient in PBS solutions. At a given mass fraction PEG or average number of grafts, the solubility of BSA-PEG conjugates is found to increase with the degree of polymerization of conjugated PEG. This result informs the synthesis of protein-conjugate systems that are optimized for the fabrication of block copolymer blend materials with maximum protein loading. Blends of BSA-PEG conjugates and block copolymer (BCP) matrices were fabricated to evaluate the dispersion morphology and solubility limits in a model system. Electron microscopy was used to evaluate the changes in lamellar spacing with increased filling fraction of BSA-PEG conjugates.

  9. Using FT-IR Spectroscopy to Elucidate the Structures of Ablative Polymers

    Science.gov (United States)

    Fan, Wendy

    2011-01-01

    The composition and structure of an ablative polymer has a multifaceted influence on its thermal, mechanical and ablative properties. Understanding the molecular level information is critical to the optimization of material performance because it helps to establish correlations with the macroscopic properties of the material, the so-called structure-property relationship. Moreover, accurate information of molecular structures is also essential to predict the thermal decomposition pathways as well as to identify decomposition species that are fundamentally important to modeling work. In this presentation, I will describe the use of infrared transmission spectroscopy (FT-IR) as a convenient tool to aid the discovery and development of thermal protection system materials.

  10. The importance of asking "how and why?" in natural product structure elucidation.

    Science.gov (United States)

    Brown, Patrick D; Lawrence, Andrew L

    2017-10-18

    Covering: up to 2017This review highlights why careful consideration of the biosynthetic origin (the how) and the biological function (the why) of a natural product can be so useful during the determination of its structure. Recent examples of structural reassignments inspired by biosynthetic and functional insights will be presented. This review will demonstrate the importance of viewing the origin, structure and function of a natural product as intertwined threads of a single story, best viewed as a whole rather than as discrete topics.

  11. Cell division factors from crown gall tumors: a strategy for structural elucidation

    International Nuclear Information System (INIS)

    Manning, K.S.

    1985-01-01

    Mitogenic compounds present in extracts of Vinca rosea crown gall tumor tissue were investigated. An isolation procedure, consisting of solvent partitions and reverse phase chromatography, has yielded a group of isomeric compounds which show activity in the tobacco pith bioassay. Initial characterizations revealed an unsaturated base, a sugar residue, a β-linked glucose, an allylic alcohol, and two methyl groups. A two part strategy of mass spectrometry (MS) in combination with proton nuclear magnetic resonance ( 1 H NMR) was envisioned. The aglycone structure would be determined by MS and the regiochemical relationships among the structural units would be defined by 1 H NMR data. The utility of this approach was demonstrated by the structure assignment of a specific inhibitor of β-D-glucuronidase, 2(S)-carboxy-3(R),4(R),5(S)-trihydroxypiperidine. The relative stereochemistry of the hydroxyls was revealed by 1 H NMR and the absolute configuration was deduced by a comparison of Cotton effects with a model compound. The use of 1 H NMR to establish regiochemical relationships was investigated. Terpenes containing quaternary carbons and methyl groups were excellent models for the regiochemical problems presented by the mitogenic factors. This 1 H NMR spectroscopy has been applied to the cell division factor structure problem. These data, with information from two dimensional nOe experiments, have defined some of the regio-relationships among the structural units present in the isolated factors

  12. Elucidating the structural basis for differing enzyme inhibitor potency by cryo-EM.

    Science.gov (United States)

    Rawson, Shaun; Bisson, Claudine; Hurdiss, Daniel L; Fazal, Asif; McPhillie, Martin J; Sedelnikova, Svetlana E; Baker, Patrick J; Rice, David W; Muench, Stephen P

    2018-02-20

    Histidine biosynthesis is an essential process in plants and microorganisms, making it an attractive target for the development of herbicides and antibacterial agents. Imidazoleglycerol-phosphate dehydratase (IGPD), a key enzyme within this pathway, has been biochemically characterized in both Saccharomyces cerevisiae ( Sc_ IGPD) and Arabidopsis thaliana ( At_ IGPD). The plant enzyme, having been the focus of in-depth structural analysis as part of an inhibitor development program, has revealed details about the reaction mechanism of IGPD, whereas the yeast enzyme has proven intractable to crystallography studies. The structure-activity relationship of potent triazole-phosphonate inhibitors of IGPD has been determined in both homologs, revealing that the lead inhibitor (C348) is an order of magnitude more potent against Sc_ IGPD than At_ IGPD; however, the molecular basis of this difference has not been established. Here we have used single-particle electron microscopy (EM) to study structural differences between the At and Sc_ IGPD homologs, which could influence the difference in inhibitor potency. The resulting EM maps at ∼3 Å are sufficient to de novo build the protein structure and identify the inhibitor binding site, which has been validated against the crystal structure of the At_ IGPD/C348 complex. The structure of Sc _IGPD reveals that a 24-amino acid insertion forms an extended loop region on the enzyme surface that lies adjacent to the active site, forming interactions with the substrate/inhibitor binding loop that may influence inhibitor potency. Overall, this study provides insights into the IGPD family and demonstrates the power of using an EM approach to study inhibitor binding. Copyright © 2018 the Author(s). Published by PNAS.

  13. A new approach for applying residual dipolar couplings as restraints in structure elucidation

    International Nuclear Information System (INIS)

    Meiler, Jens; Blomberg, Niklas; Nilges, Michael; Griesinger, Christian

    2000-01-01

    Residual dipolar couplings are useful global structural restraints. The dipolar couplings define the orientation of a vector with respect to the alignment tensor. Although the size of the alignment tensor can be derived from the distribution of the experimental dipolar couplings, its orientation with respect to the coordinate system of the molecule is unknown at the beginning of structure determination. This causes convergence problems in the simulated annealing process. We therefore propose a protocol that translates dipolar couplings into intervector projection angles, which are independent of the orientation of the alignment tensor with respect to the molecule. These restraints can be used during the whole simulated annealing protocol

  14. Structural elucidation of the polysaccharide moiety of a glycopeptide (GLPCW-II) from Ganoderma lucidum fruiting bodies.

    Science.gov (United States)

    Ye, LiBin; Zhang, JingSong; Ye, XiJun; Tang, QingJiu; Liu, YanFang; Gong, ChunYu; Du, XiuJui; Pan, YingJie

    2008-03-17

    A water-soluble glycopeptide (GLPCW-II) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE-Sepharose Fast-Flow and Sephacryl S-300 High Resolution Chromatography. The glycopeptide had a molecular weight of 1.2x10(4)Da (determined by HPLC), and consisted of approximately 90% carbohydrate and approximately 8% protein as determined using the phenol-sulfuric acid method and the BCA protein assay reagent kit, respectively. The polysaccharide moiety was composed mainly of D-Glc, L-Fuc, and D-Gal in the ratio of 1.00:1.09:4.09. To facilitate structure-activity studies, the structure of the GLPCW-II polysaccharide moiety was elucidated using 1H and 13C NMR spectroscopy including COSY, TOCSY, HMBC, HSQC, and ROESY, combined with GC-MS of methylated derivatives, and shown to consist of repeating units with the following structure: [Formula: see text].

  15. Using Jigsaw-Style Spectroscopy Problem-Solving to Elucidate Molecular Structure through Online Cooperative Learning

    Science.gov (United States)

    Winschel, Grace A.; Everett, Renata K.; Coppola, Brian P.; Shultz, Ginger V.

    2015-01-01

    Cooperative learning was employed as an instructional approach to facilitate student development of spectroscopy problem solving skills. An interactive online environment was used as a framework to structure weekly discussions around spectroscopy problems outside of class. Weekly discussions consisted of modified jigsaw-style problem solving…

  16. Isolation and Structure Elucidation of a Novel Yellow Pigment from the Marine Bacterium Pseudoalteromonas tunicata

    Directory of Open Access Journals (Sweden)

    N. Kumar

    2005-10-01

    Full Text Available The marine environment is a major source for many novel natural compounds. A new yellow pigment has been isolated from the marine bacterium P. tunicata and identified as a new member of the tambjamine class of compounds. The structural identification was achieved by a combination of 1D and 2D-NMR spectroscopy and high resolution mass spectrometry data.

  17. Structural elucidation and NMR assignments of a new pyrrolizidine alkaloid from Crotalaria vitellina Ker Gawl.

    Science.gov (United States)

    Casimiro Bezerra, Denise Aline; Fechine Tavares, Josean; dos Santos, Paula Ferreira; Castello Branco, Marianna Vieira Sobral; de Fátima Agra, Maria; Subrinho, Fernanda Lima; Braz-Filho, Raimundo; da Silva, Marcelo Sobral

    2013-08-01

    A new pyrrolizidine alkaloid, named crotavitelin, was isolated from fruits of Crotalaria vitellina, Fabaceae (Papilionoideae). The structure was established by spectroscopic techniques such as one-dimensional and two-dimensional NMR, IR, and MS. Copyright © 2013 John Wiley & Sons, Ltd.

  18. Structural and Functional Elucidation of Yeast Lanosterol 14α-Demethylase in Complex with Agrochemical Antifungals

    Science.gov (United States)

    Sagatova, Alia A.; Keniya, Mikhail V.; Negroni, Jacopo; Wilson, Rajni K.; Woods, Matthew A.; Monk, Brian C.

    2016-01-01

    Azole antifungals, known as demethylase inhibitors (DMIs), target sterol 14α-demethylase (CYP51) in the ergosterol biosynthetic pathway of fungal pathogens of both plants and humans. DMIs remain the treatment of choice in crop protection against a wide range of fungal phytopathogens that have the potential to reduce crop yields and threaten food security. We used a yeast membrane protein expression system to overexpress recombinant hexahistidine-tagged S. cerevisiae lanosterol 14α-demethylase and the Y140F or Y140H mutants of this enzyme as surrogates in order characterize interactions with DMIs. The whole-cell antifungal activity (MIC50 values) of both the R- and S-enantiomers of tebuconazole, prothioconazole (PTZ), prothioconazole-desthio, and oxo-prothioconazole (oxo-PTZ) as well as for fluquinconazole, prochloraz and a racemic mixture of difenoconazole were determined. In vitro binding studies with the affinity purified enzyme were used to show tight type II binding to the yeast enzyme for all compounds tested except PTZ and oxo-PTZ. High resolution X-ray crystal structures of ScErg11p6×His in complex with seven DMIs, including four enantiomers, reveal triazole-mediated coordination of all compounds and the specific orientation of compounds within the relatively hydrophobic binding site. Comparison with CYP51 structures from fungal pathogens including Candida albicans, Candida glabrata and Aspergillus fumigatus provides strong evidence for a highly conserved CYP51 structure including the drug binding site. The structures obtained using S. cerevisiae lanosterol 14α-demethylase in complex with these agrochemicals provide the basis for understanding the impact of mutations on azole susceptibility and a platform for the structure-directed design of the next-generation of DMIs. PMID:27907120

  19. Computer-assisted modeling: Contributions of computational approaches to elucidating macromolecular structure and function: Final report

    International Nuclear Information System (INIS)

    Walton, S.

    1987-01-01

    The Committee, asked to provide an assessment of computer-assisted modeling of molecular structure, has highlighted the signal successes and the significant limitations for a broad panoply of technologies and has projected plausible paths of development over the next decade. As with any assessment of such scope, differing opinions about present or future prospects were expressed. The conclusions and recommendations, however, represent a consensus of our views of the present status of computational efforts in this field

  20. Structural elucidation of the Brucella melitensis M antigen by high-resolution NMR at 500 MHz

    International Nuclear Information System (INIS)

    Bundle, D.R.; Cherwonogrodzky, J.W.; Perry, M.B.

    1987-01-01

    The Brucella M antigen from the species type strain Brucella melitensis 16M has been identified as a component of the cell wall lipopolysaccharide (LPS). O polysaccharide liberated from this LPS by mild acid hydrolysis exhibited M activity in serological tests and was shown to be a homopolymer of 4-formamido-4,6-dideoxy-α-D-mannopyranosyl residues arranged in an oligosaccharide repeating unit as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the native lipopolysaccharide. Structural analysis of the O polysaccharide by NMR methods was difficult due to apparent microheterogeneity of the repeating unit, which was in fact caused by the presence of rotational isomers of the N-formyl moiety. This problem was resolved by chemical modification of the polysaccharide to its amino and N-acetyl derivatives, the 500-MHz 1 H and 125-MHz 13 C NMR spectra of which could be analyzed in terms of a unique structure through application of pH-dependent β-shifts and two-dimensional techniques that included COSY, relayed COSY, and NOESY experiments together with heteronuclear C/H shift correlation spectroscopy. On the basis of these experiments and supported by methylation and periodate oxidation data, the structure of the M polysaccharide was determined as a linear polymer of unbranched pentasaccharide repeating units consisting of four 1,2-linked and one 1,3-lined 4,6-dideoxy-4-formamido-α-D-mannopyranosyl residues. The marked structural similarity of the M antigen and the A antigen, which is known to be a 1,2-linked homopolysaccharide of 4,6-dideoxy-4-formamido-α-D-mannopyranosyl units, accounts for cross-serological reactions of the two and the long-standing confusion surrounding the nature of their antigenic determinants

  1. Well-defined azazirconacyclopropane complexes supported on silica structurally determined by 2D NMR comparative elucidation

    KAUST Repository

    El Eter, Mohamad; Hamzaoui, Bilel; Abou-Hamad, Edy; Pelletier, Jeremie; Basset, Jean-Marie

    2013-01-01

    Grafting of Zr(NMe2)4 on mesoporous silica SBA-15 afforded selectively well-defined surface species SiOZr(NMe2) (η2NMeCH2). 2D solid-state NMR (1H- 13C HETCOR, Multiple Quantum) experiments have shown a unique structural rearrangement occurring on the immobilised zirconium bis methylamido ligand. © The Royal Society of Chemistry 2013.

  2. Structure elucidation of female-specific volatiles released by the parasitoid wasp Trichogramma turkestanica (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    Armin Tröger

    2014-04-01

    Full Text Available Females of the parasitoid wasp Trichogramma turkestanica produce the putative polydeoxypropionates (2E,4E,6S,8S,10S-4,6,8,10-tetramethyltrideca-2,4-diene and (2E,4E,6S,8S,10S-4,6,8,10-tetramethyltrideca-2,4-dien-1-ol or their enantiomers as sex specific volatiles. The structures were assigned on the basis of GC–MS investigations using synthetic reference compounds.

  3. Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rajput, Nav Nidhi; Murugesan, Vijayakumar; Shin, Yongwoo; Han, Kee Sung; Lau, Kah Chun; Chen, Junzheng; Liu, Jun; Curtiss, Larry A.; Mueller, Karl T.; Persson, Kristin A.

    2017-04-10

    Fundamental molecular level understanding of functional properties of liquid solutions provides an important basis for designing optimized electrolytes for numerous applica-tions. In particular, exhaustive knowledge of solvation structure, stability and transport properties is critical for developing stable electrolytes for fast charging and high energy density next-generation energy storage systems. Here we report the correlation between solubility, solvation structure and translational dynamics of a lithium salt (Li-TFSI) and polysulfides species using well-benchmarked classical molecular dynamics simulations combined with nuclear magnetic resonance (NMR). It is observed that the polysulfide chain length has a significant effect on the ion-ion and ion-solvent interaction as well as on the diffusion coefficient of the ionic species in solution. In particular, extensive cluster formation is observed in lower order poly-sulfides (Sx2-; x≤4), whereas the longer polysulfides (Sx2-; x>4) show high solubility and slow dynamics in the solu-tion. It is observed that optimal solvent/salt ratio is essen-tial to control the solubility and conductivity as the addi-tion of Li salt increases the solubility but decreases the mo-bility of the ionic species. This work provides a coupled theoretical and experimental study of bulk solvation struc-ture and transport properties of multi-component electro-lyte systems, yielding design metrics for developing optimal electrolytes with improved stability and solubility.

  4. Elucidating the mechanisms of nanodiamond-promoted structural disruption of crystallised lipid.

    Science.gov (United States)

    Hughes, Zak E; Walsh, Tiffany R

    2016-10-12

    The removal or structural disruption of crystallised lipid is a pivotal but energy-intensive step in a wide range of industrial and biological processes. Strategies to disrupt the structure of crystallised lipid in aqueous solution at lower temperatures are much needed, where nanoparticle-based strategies show enormous promise. Using the aqueous tristearin bilayer as a model for crystallised lipid, we demonstrate that the synergistic use of surfactant and detonation nanodiamonds can depress the onset temperature at which disruption of the crystallised lipid structure occurs. Our simulations reveal the molecular-scale mechanisms by which this disruption takes place, indicating that the nanodiamonds serve a dual purpose. First, the nanodiamonds are predicted to facilitate delivery of surfactant to the lipid/water interface, and second, nanodiamond adsorption acts to roughen the lipid/water interface, enhancing ingress of surfactant into the bilayer. We find the balance of the hydrophobic surface area of the nanodiamond and the nanodiamond surface charge density to be a key determinant of the effectiveness of using nanodiamonds to facilitate lipid disruption. For the nanodiamond size considered here, we identify a moderate surface charge density, that ensures the nanodiamonds are neither too hydrophobic nor too hydrophilic, to be optimal.

  5. Rhizomes of Eremostachys laciniata: Isolation and Structure Elucidation of Chemical Constituents and a Clinical Trial on Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Abbas Delazar

    2013-08-01

    Full Text Available Purpose: The purpose of this study was the isolation and structure elucidation of chemical compounds from the rhizomes of Eremostachys laciniata (L Bunge (EL, an Iranian traditional medicinal herb with a thick root and pale purple or white flowers as well as the clinical studies on the therapeutic efficacy and safety of topical application of the EL extract in the management of some inflammatory conditions, e.g., arthritis, rheumatoid arthritis and septic arthritis (Riter’s syndrome. Methods: The structures of the isolated compounds were elucidated unequivocally on the basis of one and two dimensional NMR, UV and HR-FABMS spectroscopic data analyses. A single-blinded randomized clinical trial was carried out with the extract of the rhizomes of E. laciniata (EL to determine the efficacy and safety of the traditional uses of EL compared to that of piroxicam in treatment of inflammatory diseases, e.g., osteoarthritis, rheumatoid arthritis and Reiter’s syndrome. Results: Eleven iridoid glycosides, two phenylethanoids and two phytosterols were isolated and identified for the first time from the rhizomes of EL. After 14 days of treatment with the EL and piroxicam ointments, all groups showed significant improvements compared to the control groups. EL (5% ointment induced better initial therapeutic response than piroxicam (5% onitment. Conclusion: This clinical trial established that EL was suitable for topical applications as a safe and effective complementary therapy for inflammatory diseases.

  6. Elucidating the pH-Dependent Structural Transition of T7 Bacteriophage Endolysin.

    Science.gov (United States)

    Sharma, Meenakshi; Kumar, Dinesh; Poluri, Krishna Mohan

    2016-08-23

    Bacteriophages are the most abundant and diverse biological entities on earth. Bacteriophage endolysins are unique peptidoglycan hydrolases and have huge potential as effective enzybiotics in various infectious models. T7 bacteriophage endolysin (T7L), also known as N-acetylmuramoyl-l-alanine amidase or T7 lysozyme, is a 17 kDa protein that lyses a range of Gram-negative bacteria by hydrolyzing the amide bond between N-acetylmuramoyl residues and the l-alanine of the peptidoglycan layer. Although the activity profiles of several of the T7 family members have been known for many years, the molecular basis for their pH-dependent differential activity is not clear. In this study, we explored the pH-induced structural, stability, and activity characteristics of T7L by applying a variety of biophysical techniques and protein nuclear magnetic resonance (NMR) spectroscopy. Our studies established a reversible structural transition of T7L below pH 6 and the formation of a partially denatured conformation at pH 3. This low-pH conformation is thermally stable and exposed its hydrophobic pockets. Further, NMR relaxation measurements and structural analysis unraveled that T7L is highly dynamic in its native state and a network of His residues are responsible for the observed pH-dependent conformational dynamics and transitions. As bacteriophage chimeric and engineered endolysins are being developed as novel therapeutics against multiple drug resistance pathogens, we believe that our results are of great help in designing these entities as broadband antimicrobial and/or antibacterial agents.

  7. Raman mapping in the elucidation of solid salt eutectic and near eutectic structures

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Kerridge, D. H.

    2002-01-01

    The distribution of the different components of solidified eutectic or near-eutectic salt mixtures (eutectics) was examined by use of Raman microscope mapping of the structures formed when these melts were slowly cooled. Seven binary and one ternary system were investigated. In most cases...... and the composition. When unidirectional cooling was applied it was possible for the system (KCl-Na2SO4, 60:40 mol/mol) to observe lamellar arrangements of the component phases, in an arrangement closely similar to what is frequently found among metallic or ceramic eutectics. Each area, conglomerate or lamellar, did...

  8. Spectral studies of 2-pyrazoline derivatives: structural elucidation through single crystal XRD and DFT calculations.

    Science.gov (United States)

    Chinnaraja, D; Rajalakshmi, R; Srinivasan, T; Velmurugan, D; Jayabharathi, J

    2014-04-24

    A series of biologically active N-thiocarbamoyl pyrazoline derivatives have been synthesized using anhydrous potassium carbonate as the catalyst. All the synthesized compounds were characterized by FT-IR, (1)H NMR, (13)C NMR spectral studies, LCMS, CHN Analysis and X-ray diffraction analysis (compound 7). In order to supplement the XRD parameters, molecular modelling was carried out by Gaussian 03W. From the optimized structure, the energy, dipolemoment and HOMO-LUMO energies of all the systems were calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Tannin structural elucidation and quantitative ³¹P NMR analysis. 2. Hydrolyzable tannins and proanthocyanidins.

    Science.gov (United States)

    Melone, Federica; Saladino, Raffaele; Lange, Heiko; Crestini, Claudia

    2013-10-02

    An unprecedented analytical method that allows simultaneous structural and quantitative characterization of all functional groups present in tannins is reported. In situ labeling of all labile H groups (aliphatic and phenolic hydroxyls and carboxylic acids) with a phosphorus-containing reagent (Cl-TMDP) followed by quantitative ³¹P NMR acquisition constitutes a novel fast and reliable analytical tool for the analysis of tannins and proanthocyanidins with significant implications for the fields of food and feed analyses, tannery, and the development of natural polyphenolics containing products.

  10. Structural elucidation and physicochemical properties of an organic NLO crystal: 4-Nitrotoluene-2-sulphonic acid dihydrate

    Science.gov (United States)

    Sangeetha, K.; Guru Prasad, L.; Mathammal, R.

    2018-03-01

    4-nitrotoluene-2-sulphonic acid dihydrate single crystals have been developed using slow evaporation technique in methanol. Lattice parameters of the NTSAD crystal have been calculated and it confirms the grown material. The intermolecular interactions are studied from the 3D Hirshfeld surface analysis and 2D fingerprint plots. The NMR spectral analysis has been carried out to confirm the molecular structure of the grown material. Optical properties have been obtained from UV-VIS spectral analysis and photoluminescence studies. Frequency conversion property of the NTSAD crystal was investigated with the aid of Kurtz and Perry method.

  11. Structural elucidation and molecular docking of a novel antibiotic compound from cyanobacterium Nostoc sp. MGL001

    Directory of Open Access Journals (Sweden)

    Niveshika No Name

    2016-11-01

    Full Text Available Cyanobacteria are rich source of array of bioactive compounds. The present study reports a novel antibacterial bioactive compound purified from cyanobacterium Nostoc sp. MGL001 using various chromatographic techniques viz. thin layer chromatography (TLC and high performance liquid chromatography (HPLC. Further characterization was done using electrospray ionisation mass spectroscopy (ESIMS and nuclear magnetic resonance (NMR and predicted structure of bioactive compound was 9-Ethyliminomethyl-12-(morpholin - 4 - ylmethoxy -5, 8, 13, 16 – tetraaza – hexacene - 2, 3 dicarboxylic acid (EMTAHDCA. Structure of EMTAHDCA clearly indicated that it is a novel compound that was not reported in literature or natural product database. The compound exhibited growth inhibiting effects mainly against the gram negative bacterial strains and produced maximum zone of inhibition at 150 μg/mL concentration. The compound was evaluated through in silico studies for its ability to bind 30S ribosomal fragment (PDB ID: 1YRJ, 1MWL, 1J7T and 1LC4 and OmpF porin protein (4GCP, 4GCQ and 4GCS which are the common targets of various antibiotic drugs. Comparative molecular docking study revealed that EMTAHDCA has strong binding affinity for these selected targets in comparison to a number of most commonly used antibiotics. The ability of EMTAHDCA to bind the active sites on the proteins and 30S ribosomal fragments where the antibiotic drugs generally bind indicated that it is functionally similar to the commercially available drugs.

  12. Spreading properties of cosmetic emollients: Use of synthetic skin surface to elucidate structural effect.

    Science.gov (United States)

    Douguet, Marine; Picard, Céline; Savary, Géraldine; Merlaud, Fabien; Loubat-Bouleuc, Nathalie; Grisel, Michel

    2017-06-01

    The study focuses on the impact of structural and physicochemical properties of emollients on their spreadability. Fifty-three emollients, among which esters, silicones, vegetable and mineral oils, have been characterized. Their viscosity, surface tension, density and spreadability have been measured. Vitro-skin ® , an artificial skin substitute, was used as an artificial porous substrate to measure spreadability. Two different methods have been selected to characterize spreadability, namely contact angle and spreading value. Dynamic contact angle measurements showed that emollient spreadability is first governed by spontaneous spreading and that, in a second phase, absorption and migration into the porous substrate becomes the driver of the extension of the spreading area. Statistical analysis of physicochemical and spreading value data revealed that viscosity has a major impact on the spreading behavior of emollients whatever their chemical type. A special emphasis was placed on the ester family in which chemical diversity is very wide. The results highlighted a difference between "high viscosity esters" for which viscosity is the main factor impacting spreadability and "low viscosity esters" for which structural variations (mono/diester, saturated/unsaturated chain, linear/branched chain) have to be considered in addition to viscosity. Linear regressions were used to express spreading value as a function of viscosity for each of the four emollient families tested (esters, silicones, vegetable and mineral oils). These regressions allowed the development of reliable predictive models as a powerful tool for formulators to forecast spreadability of emollients. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Experimental and theoretical elucidation of structural and antioxidant properties of vanillylmandelic acid and its carboxylate anion

    Science.gov (United States)

    Dimić, Dušan; Milenković, Dejan; Ilić, Jelica; Šmit, Biljana; Amić, Ana; Marković, Zoran; Dimitrić Marković, Jasmina

    2018-06-01

    Vanillylmandelic acid (VMA), an important metabolite of catecholamines that is routinely screened as tumor marker, was investigated by the various spectroscopic techniques (IR, Raman, UV-Vis, antioxidant decolorization assay and NMR). Structures optimized by the employment of five common functionals (M05-2X, M06-2X, B3LYP, CAM-B3LYP, B3LYP-D3) were compared with the crystallographic data. The M05-2X functional reproduced the most reliable experimental bond lengths and angles (correlation coefficient >0.999). The importance of intramolecular hydrogen bonds for structural stability was discussed and quantified by the NBO analysis. The most prominent bands in vibrational spectrum were analyzed and compared to the experimental data. The positions of the carbon and hydrogen atoms in NMR spectra were well reproduced. The differences in UV-Vis spectrum were investigated by adding the explicit solvent and by performing NBO and QTAIM analyses. The discrepancy in the two spectra of about 50 nm could be explained by the solvent effect on carboxyl group. The most probable antioxidant activity mechanism was discussed for VMA and its carboxylate anion. The Molecular Docking study with the C - reactive protein additionally proved that variety of functional groups present in VMA and its anion allowed strong hydrogen and hydrophobic interactions.

  14. Structure elucidation of a bioactive polysaccharide from fruiting bodies of Hericium erinaceus in different maturation stages.

    Science.gov (United States)

    Li, Qiao-Zhen; Wu, Di; Zhou, Shuai; Liu, Yan-Fang; Li, Zheng-Peng; Feng, Jie; Yang, Yan

    2016-06-25

    HPB-3, a heteropolysaccharide, with a mean molecular weight of 1.5×10(4)Da, was obtained from the maturating-stage IV, V and VI fruiting body of Hericium erinaceus, exhibited higher macrophages stimulation activities, was able to upregulate the functional events mediated by activated macrophages, such as production of nitric oxide (NO). Monosaccharide composition analysis showed that HPB-3 comprised l-fucose, d-galactose and d-glucose in the ratio of 5.2:23.9:1. Its chemical structure was characterized by sugar and methylation analysis, along with (1)H and (13)C NMR spectroscopy, including (1)H-(1)H COSY, TOCSY, NOESY, HMQC and HMBC experiments. The results indicated that HPB-3 contained a-(1/6)-linked galactopyranosyl backbone, partially with a side chain composed of α-l-fucopyranose at the O-2 position. The predicted primary structure of the polysaccharide was established as below. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Molecular Insights into the Transmembrane Domain of the Thyrotropin Receptor.

    Directory of Open Access Journals (Sweden)

    Vanessa Chantreau

    Full Text Available The thyrotropin receptor (TSHR is a G protein-coupled receptor (GPCR that is member of the leucine-rich repeat subfamily (LGR. In the absence of crystal structure, the success of rational design of ligands targeting the receptor internal cavity depends on the quality of the TSHR models built. In this subfamily, transmembrane helices (TM 2 and 5 are characterized by the absence of proline compared to most receptors, raising the question of the structural conformation of these helices. To gain insight into the structural properties of these helices, we carried out bioinformatics and experimental studies. Evolutionary analysis of the LGR family revealed a deletion in TM5 but provided no information on TM2. Wild type residues at positions 2.58, 2.59 or 2.60 in TM2 and/or at position 5.50 in TM5 were substituted to proline. Depending on the position of the proline substitution, different effects were observed on membrane expression, glycosylation, constitutive cAMP activity and responses to thyrotropin. Only proline substitution at position 2.59 maintained complex glycosylation and high membrane expression, supporting occurrence of a bulged TM2. The TSHR transmembrane domain was modeled by homology with the orexin 2 receptor, using a protocol that forced the deletion of one residue in the TM5 bulge of the template. The stability of the model was assessed by molecular dynamics simulations. TM5 straightened during the equilibration phase and was stable for the remainder of the simulations. Our data support a structural model of the TSHR transmembrane domain with a bulged TM2 and a straight TM5 that is specific of glycoprotein hormone receptors.

  16. Production, Structural Elucidation, and In Vitro Antitumor Activity of Trehalose Lipid Biosurfactant from Nocardia farcinica Strain.

    Science.gov (United States)

    Christova, Nelly; Lang, Siegmund; Wray, Victor; Kaloyanov, Kaloyan; Konstantinov, Spiro; Stoineva, Ivanka

    2015-04-01

    The objective of this study was to isolate and identify the chemical structure of a biosurfactant produced by Nocardia farcinica strain BN26 isolated from soil, and evaluate its in vitro antitumor activity on a panel of human cancer cell lines. Strain BN26 was found to produce glycolipid biosurfactant on n-hexadecane as the sole carbon source. The biosurfactant was purified using medium-pressure liquid chromatography and characterized as trehalose lipid tetraester (THL) by nuclear magnetic resonance spectroscopy and mass spectrometry. Subsequently, the cytotoxic effects of THL on cancer cell lines BV-173, KE-37 (SKW-3), HL-60, HL-60/DOX, and JMSU-1 were evaluated by MTT assay. It was shown that THL exerted concentration-dependent antiproliferative activity against the human tumor cell lines and mediated cell death by the induction of partial oligonucleosomal DNA fragmentation. These findings suggest that THL could be of potential to apply in biomedicine as a therapeutic agent.

  17. X-ray Crystal Structures Elucidate the Nucleotidyl Transfer Reaction of Transcript Initiation Using Two Nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    M Gleghorn; E Davydova; R Basu; L Rothman-Denes; K Murakami

    2011-12-31

    We have determined the X-ray crystal structures of the pre- and postcatalytic forms of the initiation complex of bacteriophage N4 RNA polymerase that provide the complete set of atomic images depicting the process of transcript initiation by a single-subunit RNA polymerase. As observed during T7 RNA polymerase transcript elongation, substrate loading for the initiation process also drives a conformational change of the O helix, but only the correct base pairing between the +2 substrate and DNA base is able to complete the O-helix conformational transition. Substrate binding also facilitates catalytic metal binding that leads to alignment of the reactive groups of substrates for the nucleotidyl transfer reaction. Although all nucleic acid polymerases use two divalent metals for catalysis, they differ in the requirements and the timing of binding of each metal. In the case of bacteriophage RNA polymerase, we propose that catalytic metal binding is the last step before the nucleotidyl transfer reaction.

  18. Isolation and structure elucidation of pectic polysaccharide from rose hip fruits (Rosa canina L.).

    Science.gov (United States)

    Ognyanov, Manol; Remoroza, Connie; Schols, Henk A; Georgiev, Yordan; Kratchanova, Maria; Kratchanov, Christo

    2016-10-20

    A pectic polysaccharide from rose hip (RH) fruits has been obtained by extraction with 1% aqueous citric acid. It was found that the polysaccharide fraction mainly consisted of galacturonic acid (45.5%) next to galactose (5.5%) and arabinose (4.7%). RH pectin is having a relatively high degree of methylesterification (62%) and acetylation (10%) and consists of different molecular weight populations in the range of 10-100kDa. Enzymatic fingerprinting was performed using a combination of pectin lyase (PL) and endo-polygalacturonase. Detailed information about the structure and level of galacturonic acid oligomers released was obtained using LC-HILIC-MS/ELSD and HPAEC. Predominantly, unsaturated and methyl-esterified oligomers (DP 3-5) were released indicating that high proportions of methylesterified 'PL degradable' areas were present within the pectin. The data revealed that homogalacturonan is the main building block of the extracted pectin and consists of long methylesterified/acetylated GalA sequences interspersed with small blocks of non-methyl-esterified GalA units. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Structure elucidation and chemical synthesis of stigmolone, a novel type of prokaryotic pheromone.

    Science.gov (United States)

    Hull, W E; Berkessel, A; Plaga, W

    1998-09-15

    Approximately 2 micromol of a novel prokaryotic pheromone, involved in starvation-induced aggregation and formation of fruiting bodies by the myxobacterium Stigmatella aurantiaca, were isolated by a large-scale elution procedure. The pheromone was purified by HPLC, and high-resolution MS, IR, 1H-NMR, and 13C-NMR were used to identify the active substance as the hydroxy ketone 2,5, 8-trimethyl-8-hydroxy-nonan-4-one, which has been named stigmolone. The analysis was complicated by a solvent-dependent equilibrium between stigmolone and the cyclic enol-ether 3,4-dihydro-2,2, 5-trimethyl-6-(2-methylpropyl)-2H-pyran formed by intramolecular nucleophilic attack of the 8-OH group at the ketone C4 followed by loss of H2O. Both compounds were synthesized chemically, and their structures were confirmed by NMR analysis. Natural and synthetic stigmolone have the same biological activity at ca. 1 nM concentration.

  20. Isolation and structure elucidation of some compounds of Solidago gigantea var. serotina (O. Kuntze) Cronquist

    International Nuclear Information System (INIS)

    Lichtenberger, E.

    1985-03-01

    Studies on plants of the genus Solidago used in folk medicine as a remedy against diseases of the urinary-system induced the investigation of Solidago gigantea Aiton var. serotina (O. Kuntze) Cronquist = S. serotina. A methanolic extract of the aerial parts was examined for the biologically active saponin complex. The most effective constituents were found to be a mixture of closely related triterpene glycosides named saponin G, H, I and saponin K. Fractionation over a series of silicagel columns and droplet countercurrent chromatographies resulted in pure saponin G and saponin H. The screening of the hydrolized glycosides afforded the genins bayogenin as major compound, oleanolic acid and three additional aglycones in trace quantities. The identy of bayogenin, oleanolic acid and bayogeninglucosid was established by mass-, 1 H-NMR- and 13 C-NMR-measurements and by direct comparison with authentic samples. Gas chromatographic analysis of the sugar moiety yielded rhamnose, xylose, glucose and 6-desoxyglucose after KILIANI-degradation in a ratio 3:3:1:1. Beside the triterpene derivatives, mentioned above, we found a diterpene, sterol and sterolglycosed as well. The diterpene structure was confirmed by UV-, IR-, mass-, 1 H-NMR- and 13 C-NMR-spectroscopy. This diterpene was not previously known to be present in S. serotina. The sterol-compounds could be determined as α-spinasterol and the respective hexosid. (Author)

  1. Dihydropyridazinone cardiotonics: discovery of LY195115 and elucidation of structural features necessary for optimal inotropic activity

    Energy Technology Data Exchange (ETDEWEB)

    Krushinski, J.H.; Hayes, J.S.; Beedle, E.E.; Pollock, G.D.; Wilson, H.; Robertson, D.W.

    1986-03-05

    A series of 4,5-dihydro-6-aryl-3(/sup 2/H)-pyridazinones has been examined for inotropic activity. The optimal compound of the series, LY195115 (1,3-dihydro-3,3-dimethyl-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)-/sup 2/H-indol-2-one), is one of the most potent and long-acting oral inotropes described to date. ED/sub 50/'s of LY195115, CI-914 and milrinone after i.v. administration to pentobarbital anesthetized dogs were 6.8, 46 and 37 ..mu..g/kg, respectively. ED/sub 50/'s after oral administration to conscious dogs were 25, 1000 and 500 ..mu..g/kg, respectively. For optimal positive inotropic activity and oral bioavailability in this series, the following structural features are necessary: (1) dihydropyridazinone ring with the nitrogen unsubstituted; (2) a hydrogen-bond acceptor substituent with a sigma value of ca 0.0 para to the dihydropyridazinone moiety; and (3) additional sterically undemanding lipophilic substituents adjacent to the hydrogen-bond acceptor site.

  2. Dihydropyridazinone cardiotonics: discovery of LY195115 and elucidation of structural features necessary for optimal inotropic activity

    International Nuclear Information System (INIS)

    Krushinski, J.H.; Hayes, J.S.; Beedle, E.E.; Pollock, G.D.; Wilson, H.; Robertson, D.W.

    1986-01-01

    A series of 4,5-dihydro-6-aryl-3( 2 H)-pyridazinones has been examined for inotropic activity. The optimal compound of the series, LY195115 (1,3-dihydro-3,3-dimethyl-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)- 2 H-indol-2-one), is one of the most potent and long-acting oral inotropes described to date. ED 50 's of LY195115, CI-914 and milrinone after i.v. administration to pentobarbital anesthetized dogs were 6.8, 46 and 37 μg/kg, respectively. ED 50 's after oral administration to conscious dogs were 25, 1000 and 500 μg/kg, respectively. For optimal positive inotropic activity and oral bioavailability in this series, the following structural features are necessary: (1) dihydropyridazinone ring with the nitrogen unsubstituted; (2) a hydrogen-bond acceptor substituent with a σ value of ca 0.0 para to the dihydropyridazinone moiety; and (3) additional sterically undemanding lipophilic substituents adjacent to the hydrogen-bond acceptor site

  3. Structure elucidation and antioxidant activity of a novel polysaccharide isolated from Boletus speciosus Forst.

    Science.gov (United States)

    Ding, Xiang; Hou, Yi-ling; Hou, Wan-ru

    2012-04-01

    In this study, a novel heteropolysaccharide was isolated from the fruiting bodies of Boletus speciosus Forst through DEAE-cellulose column and Sephadex G-200 column. The Boletus speciosus Forst polysaccharide (BSFP-1) had a molecular weight of 1.33×10(4) Da and was mainly composed of l-Man and d-Gal which ratios were 2:1. Structural features of Boletus speciosus Forst polysaccharide (BSFP-1) were investigated by a combination of total hydrolysis, methylation analysis, gas chromatography-mass spectrometry (GC-MS), infrared (IR) spectra and nuclear magnetic resonance (NMR) spectroscopy. The results indicated that Boletus speciosus Forst polysaccharide (BSFP-1) had a backbone of (1→4)-α-l-mannopyranose residues which branches at O-6 based on the experimental results. The branches were mainly composed of one with →1)-α-d-galactopyranose residue. The antioxidant activity of BSFP-1 was evaluated with two biochemical methods, including 1,1-diphenyl-2-picrylhydrazyl (DPPH(-)) radical scavenging, scavenging activity of 2,2'-azino-bis(3-ethylbenzthiazoline-6-suphonic acid)diammonium (ABTS(+)) radical. The results indicated that BSFP-1 showed strong antioxidant. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Characteristic conformation of Mosher's amide elucidated using the cambridge structural database.

    Science.gov (United States)

    Ichikawa, Akio; Ono, Hiroshi; Mikata, Yuji

    2015-07-16

    Conformations of the crystalline 3,3,3-trifluoro-2-methoxy-2-phenylpropanamide derivatives (MTPA amides) deposited in the Cambridge Structural Database (CSD) were examined statistically as Racid-enantiomers. The majority of dihedral angles (48/58, ca. 83%) of the amide carbonyl groups and the trifluoromethyl groups ranged from -30° to 0° with an average angle θ1 of -13°. The other conformational properties were also clarified: (1) one of the fluorine atoms was antiperiplanar (ap) to the amide carbonyl group, forming a staggered conformation; (2) the MTPA amides prepared from primary amines showed a Z form in amide moieties; (3) in the case of the MTPA amide prepared from a primary amine possessing secondary alkyl groups (i.e., Mosher-type MTPA amide), the dihedral angles between the methine groups and the carbonyl groups were syn and indicative of a moderate conformational flexibility; (4) the phenyl plane was inclined from the O-Cchiral bond of the methoxy moiety with an average dihedral angle θ2 of +21°; (5) the methyl group of the methoxy moiety was ap to the ipso-carbon atom of the phenyl group.

  5. Isolation and Structure Elucidation of Uncommon Secondary Metabolites from Cistus salviifolius L.

    Directory of Open Access Journals (Sweden)

    Perihan Gürbüz

    2015-01-01

    Full Text Available To our knowledge this is the first report on the isolation of a flavonoid glycoside: quercetin 3-O-α-arabinopyranoside (5, two phenylbutanon glycosides: 4-(4'-O-[6''-O-galloyl-β-galactopyranosyl]-3'-hydroxyphenyl-butan-2-on (8, 4-(3'-O-β-glucopyranosyl-4'-hydroxyphenyl-butan-2-on (9, one phloroglucinol glycoside: 1-O-β-glucopyranosyl-3,5-dimethoxybenzene (10 and a steroid glycoside: sitosterol-3-O-(6''-O-butanoyl-β-galactopyranoside (14 from the Cistus species (Cistaceae. Additional to these compounds three flavonol aglycones: kaempferol (1, quercetin (2, myricetin (3; three flavonoid glycosides; kaempferol 3-O-β-(6''-O-trans-p-coumaroyl-glucopyranoside (4, quercetin 3-O-β-galactopyranoside (6, myricetin 3-O-β-galactopyranoside (7; one phloroglucinol glycoside: 1-O-β-glucopyranosyl-3,5-dimethoxybenzene (11; one steroid aglycone: β-sitosterol (12; one steroid glycoside: Sitosterol-3-O- β-glucopyranoside (13 were isolated from the aerial parts of the Cistus salviifolius L.. Their structures were identified using spectral methods (UV, IR, 1D- and 2D-NMR, and ESI-MS.

  6. [Isolation and structure elucidation of further new saponins from Solidago canadensis].

    Science.gov (United States)

    Reznicek, G; Jurenitsch, J; Freiler, M; Korhammer, S; Haslinger, E; Hiller, K; Kubelka, W

    1992-02-01

    Four new main saponins (canadensis-saponins 5-8) (compounds 5-8) were isolated from Solidago canadensis L. (Asteraceae). Using GC/MS, FAB-MS, and mainly 2D-NMR techniques their structures were identified as 3-O-[beta-D-glucopyranosyl(1----3)-beta-D- glucopyranosyl]-28-O-[beta-D-galactopyranosyl(1----2)-alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D-apio -D- furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl-(1----)]-bayog enin(5),3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[beta-D- galactopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta-D- xylopyranosyl-(1----4)-[beta-D-xylopyranosyl-(1----3)]-alpha-L- rhamnopyranosyl-(1----2)-[beta-D-apio-D-furanosyl-(1----3)]- arabinopyranosyl-(1----)]bayogenin(6),3-O-[beta-D-glucopy ran osyl-(1----3)- beta-D-glucopyranosyl]-28-O-[beta-D-galactopyranosyl-(1----2)- alpha-L-rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[alpha-L- rhamnopyranosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl-(1----)]-++ +bayogenin (7), and 3-O-[beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-[O- beta-D-galactopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta-D - xylopyranosyl-(1----4)-[beta-D-xylopyranosyl-(1----3)]-alpha-L- rhamnopyranosyl-(1----2)-[alpha-L-rhamnopyranosyl-(1----3)]arabinopyr anosyl - (1----)[-bayogenin (8).

  7. Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

    International Nuclear Information System (INIS)

    Oliveira, Dalglish G. de; Almeida, Cecilia M.C. de; Silva, Consuelo Y.Y. e; Arruda, Mara S.P.; Arruda, Alberto C.; Silva, Milton N. da; Lopes, Dielly C.F.; Yamada, Elizabeth S.; Costa, Edmar T. da; MFilho, Arnaldo Jorge

    2012-01-01

    Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2'',2''dimethylchromene-(5''6'':6,7)- dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'',2''-dimethylchromene-(5'',6'':6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy- 6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 ± 1.6%) when the cultures were exposed to 30 nmol L -1 rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 μg mL -1 ) and 30 nmol L -1 rotenone resulted in values of cell viability similar to control groups (99.6 ± 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction. (author)

  8. Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Dalglish G. de; Almeida, Cecilia M.C. de; Silva, Consuelo Y.Y. e; Arruda, Mara S.P.; Arruda, Alberto C.; Silva, Milton N. da, E-mail: yumilton@yahoo.com.br [Laboratorio de Cromatografia Liquida, Universidade Federal do Para, Guama, Belem-PA (Brazil); Lopes, Dielly C.F.; Yamada, Elizabeth S.; Costa, Edmar T. da; MFilho, Arnaldo Jorge [Laboratorio de Neuropatologia Experimental, Hospital Universitario Barros Barreto, Guama, Belem-PA (Brazil)

    2012-11-15

    Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2'',2''dimethylchromene-(5''6'':6,7)- dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'',2''-dimethylchromene-(5'',6'':6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy- 6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 {+-} 1.6%) when the cultures were exposed to 30 nmol L{sup -1}rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 {mu}g mL{sup -1}) and 30 nmol L{sup -1} rotenone resulted in values of cell viability similar to control groups (99.6 {+-} 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction. (author)

  9. Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Dalglish G. de; Almeida, Cecilia M.C. de; Silva, Consuelo Y.Y. e; Arruda, Mara S.P.; Arruda, Alberto C., E-mail: yumilton@yahoo.com.br [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Lab. de Cromatografia Liquida; Lopes, Dielly C.F.; Yamada, Elizabeth S.; Costa, Edmar T. da; Silva, Milton N. da [Hospital Universitario Barros Barreto, Belem, PA (Brazil). Lab. de Neuropatologia Experimental

    2012-10-15

    Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2{sup ,}2{sup -}dimethylchromene-(5''6''6,7)- dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'', 2''-dimethylchromene-(5{sup ,}6{sup :}6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy- 6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 {+-} 1.6%) when the cultures were exposed to 30 nmol L{sup -1} rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 {mu}g mL{sup -1}) and 30 nmol L{sup -1} rotenone resulted in values of cell viability similar to control groups (99.6 {+-} 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction. (author)

  10. Structural elucidation of fucosylated chondroitin sulfates from sea cucumber using FTICR-MS/MS.

    Science.gov (United States)

    Agyekum, Isaac; Pepi, Lauren; Yu, Yanlei; Li, Junhui; Yan, Lufeng; Linhardt, Robert J; Chen, Shiguo; Amster, I Jonathan

    2018-02-01

    Fucosylated chondroitin sulfates are complex polysaccharides extracted from sea cucumber. They have been extensively studied for their anticoagulant properties and have been implicated in other biological activities. While nuclear magnetic resonance spectroscopy has been used to extensively characterize fucosylated chondroitin sulfate oligomers, we herein report the first detailed mass characterization of fucosylated chondroitin sulfate using high-resolution Fourier transform ion cyclotron resonance mass spectrometry. The two species of fucosylated chondroitin sulfates considered for this work include Pearsonothuria graeffei (FCS-Pg) and Isostichopus badionotus (FCS-Ib). Fucosylated chondroitin sulfate oligosaccharides were prepared by N-deacetylation-deaminative cleavage of the two fucosylated chondroitin sulfates and purified by repeated gel filtration. Accurate mass measurements obtained from electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry measurements confirmed the oligomeric nature of these two fucosylated chondroitin sulfate oligosaccharides with each trisaccharide repeating unit averaging four sulfates per trisaccharide. Collision-induced dissociation of efficiently deprotonated molecular ions through Na/H + exchange proved useful in providing structurally relevant glycosidic and cross-ring product ions, capable of assigning the sulfate modifications on the fucosylated chondroitin sulfate oligomers. Careful examination of the tandem mass spectrometry of both species deferring in the positions of sulfate groups on the fucose residue (FCS-Pg-3,4- OS) and (FCS-Ib-2,4- OS) revealed cross-ring products 0,2 A αf and 2,4 X 2αf which were diagnostic for (FCS-Pg-3,4- OS) and 0,2 X 2αf diagnostic for (FCS-Ib-2,4- OS). Mass spectrometry and tandem mass spectrometry data acquired for both species varying in oligomer length (dp3-dp15) are presented.

  11. Elucidating the interaction between light competition and herbivore feeding patterns using functional–structural plant modelling

    Science.gov (United States)

    de Vries, Jorad; Poelman, Erik H; Anten, Niels; Evers, Jochem B

    2018-01-01

    Abstract Background and Aims Plants usually compete with neighbouring plants for resources such as light as well as defend themselves against herbivorous insects. This requires investment of limiting resources, resulting in optimal resource distribution patterns and trade-offs between growth- and defence-related traits. A plant’s competitive success is determined by the spatial distribution of its resources in the canopy. The spatial distribution of herbivory in the canopy in turn differs between herbivore species as the level of herbivore specialization determines their response to the distribution of resources and defences in the canopy. Here, we investigated to what extent competition for light affects plant susceptibility to herbivores with different feeding preferences. Methods To quantify interactions between herbivory and competition, we developed and evaluated a 3-D spatially explicit functional–structural plant model for Brassica nigra that mechanistically simulates competition in a dynamic light environment, and also explicitly models leaf area removal by herbivores with different feeding preferences. With this novel approach, we can quantitatively explore the extent to which herbivore feeding location and light competition interact in their effect on plant performance. Key Results Our results indicate that there is indeed a strong interaction between levels of plant–plant competition and herbivore feeding preference. When plants did not compete, herbivory had relatively small effects irrespective of feeding preference. Conversely, when plants competed, herbivores with a preference for young leaves had a strong negative effect on the competitiveness and subsequent performance of the plant, whereas herbivores with a preference for old leaves did not. Conclusions Our study predicts how plant susceptibility to herbivory depends on the composition of the herbivore community and the level of plant competition, and highlights the importance of considering

  12. Elucidating the interaction between light competition and herbivore feeding patterns using functional-structural plant modelling.

    Science.gov (United States)

    de Vries, Jorad; Poelman, Erik H; Anten, Niels; Evers, Jochem B

    2018-01-24

    Plants usually compete with neighbouring plants for resources such as light as well as defend themselves against herbivorous insects. This requires investment of limiting resources, resulting in optimal resource distribution patterns and trade-offs between growth- and defence-related traits. A plant's competitive success is determined by the spatial distribution of its resources in the canopy. The spatial distribution of herbivory in the canopy in turn differs between herbivore species as the level of herbivore specialization determines their response to the distribution of resources and defences in the canopy. Here, we investigated to what extent competition for light affects plant susceptibility to herbivores with different feeding preferences. To quantify interactions between herbivory and competition, we developed and evaluated a 3-D spatially explicit functional-structural plant model for Brassica nigra that mechanistically simulates competition in a dynamic light environment, and also explicitly models leaf area removal by herbivores with different feeding preferences. With this novel approach, we can quantitatively explore the extent to which herbivore feeding location and light competition interact in their effect on plant performance. Our results indicate that there is indeed a strong interaction between levels of plant-plant competition and herbivore feeding preference. When plants did not compete, herbivory had relatively small effects irrespective of feeding preference. Conversely, when plants competed, herbivores with a preference for young leaves had a strong negative effect on the competitiveness and subsequent performance of the plant, whereas herbivores with a preference for old leaves did not. Our study predicts how plant susceptibility to herbivory depends on the composition of the herbivore community and the level of plant competition, and highlights the importance of considering the full range of dynamics in plant-plant-herbivore interactions

  13. A Structural and Functional Elucidation of the Rumen Microbiome Influenced by Various Diets and Microenvironments

    Directory of Open Access Journals (Sweden)

    Simon Deusch

    2017-08-01

    Full Text Available The structure and function of the microbiome inhabiting the rumen are, amongst other factors, mainly shaped by the animal's feed intake. Describing the influence of different diets on the inherent community arrangement and associated metabolic activities of the most active ruminal fractions (bacteria and archaea is of great interest for animal nutrition, biotechnology, and climatology. Samples were obtained from three fistulated Jersey cows rotationally fed with corn silage, grass silage or grass hay, each supplemented with a concentrate mixture. Samples were fractionated into ruminal fluid, particle-associated rumen liquid, and solid matter. DNA, proteins and metabolites were analyzed subsequently. DNA extracts were used for Illumina sequencing of the 16S rRNA gene and the metabolomes of rumen fluids were determined by 500 MHz-NMR spectroscopy. Tryptic peptides derived from protein extracts were measured by LC-ESI-MS/MS and spectra were processed by a two-step database search for quantitative metaproteome characterization. Data are available via ProteomeXchange with the identifier PXD006070. Protein- and DNA-based datasets revealed significant differences between sample fractions and diets and affirmed similar trends concerning shifts in phylogenetic composition. Ribosomal genes and proteins belonging to the phylum of Proteobacteria, particularly Succinivibrionaceae, exhibited a higher abundance in corn silage-based samples while fiber-degraders of the Lachnospiraceae family emerged in great quantities throughout the solid phase fractions. The analysis of 8163 quantified bacterial proteins revealed the presence of 166 carbohydrate active enzymes in varying abundance. Cellulosome affiliated proteins were less expressed in the grass silage, glycoside hydrolases appeared in slightest numbers in the corn silage. Most expressed glycoside hydrolases belonged to families 57 and 2. Enzymes analogous to ABC transporters for amino acids and

  14. Structural elucidation and identification of a new derivative of phenethylamine using quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Sekuła, Karolina; Zuba, Dariusz

    2013-09-30

    In recent years, the phenomenon of uncontrolled distribution of new psychoactive substances that were marketed without prior toxicological studies has been observed. Because many designer drugs are related in chemical structure, the potential for misidentifying them is an important problem. It is therefore essential to develop an analytical procedure for unequivocal elucidation of the structures of these compounds. The issue has been discussed in the context of 25I-NBMD [2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2,3-methylenedioxyphenyl)methyl]ethanamine], a psychoactive substance first discovered on the drug market in 2012. The substance was extracted from blotter papers with methanol. Separation was achieved via liquid chromatography. Analysis was conducted by electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOFMS). Identification of the psychoactive component was supported by electron impact gas chromatography/mass spectrometry (GC/EI-MS). The high accuracy of the LC/ESI-QTOFMS method allowed the molecular mass of the investigated substance (M(exp) = 441.0438 Da; mass error, ∆m = 0.2 ppm) and the formulae of ions formed during fragmentation to be determined. The main ions were recorded at m/z = 135.0440, 290.9876 and 305.9981. Structures of the obtained ions were elucidated in the tandem mass spectrometry (MS/MS) experiments by comparing them to mass spectra of previously detected derivatives of phenethylamine. The performed study indicated the potential for using LC/QTOFMS method to identify new designer drugs. This technique can be used supplementary to standard GC/MS. Prior knowledge of the fragmentation mechanisms of phenethylamines allowed to predict the mass spectra of the novel substance--25I-NBMD. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Rapid screening and structural elucidation of a novel sibutramine analogue in a weight loss supplement: 11-desisobutyl-11-benzylsibutramine.

    Science.gov (United States)

    Mans, Daniel J; Gucinski, Ashley C; Dunn, Jamie D; Gryniewicz-Ruzicka, Connie M; Mecker-Pogue, Laura C; Kao, Jeff L-F; Ge, Xia

    2013-09-01

    A novel analogue of sibutramine, 11-desisobutyl-11-benzylsibutramine, has been discovered. During routine ion mobility spectrometry (IMS) screening of a weight loss supplement collected at an US FDA import operation facility an unknown peak was observed. Further analysis of the supplement by liquid chromatography-mass spectrometry (LC-MS) and high resolution mass spectrometry revealed an unknown peak with a relative retention time of 1.04 with respect to sibutramine and a predicted formula of C20H24NCl. In order to elucidate the analogue's structure, it was isolated from the supplement and characterized by tandem mass spectrometry and nuclear magnetic resonance (NMR), which revealed the analogue possessed a benzyl moiety at the 11 position in place of the isobutyl group associated with sibutramine. Copyright © 2013. Published by Elsevier B.V.

  16. Syntheses, structural elucidation, thermal properties, theoretical quantum chemical studies (DFT and biological studies of barbituric–hydrazone complexes

    Directory of Open Access Journals (Sweden)

    Amina A. Soayed

    2015-03-01

    Full Text Available Condensation of barbituric acid with hydrazine hydrate yielded barbiturichydrazone (L which was characterized using IR, 1H NMR and mass spectra. The Co(II, Ni(II and Cu(II complexes derived from this ligand have been synthesized and structurally characterized by elemental analyses, spectroscopic methods (IR, UV–Vis and ESR and thermal analyses (TGA, DTG and DTA and the structures were further elucidated using quantum chemical density functional theory. Complexes of L were found to have the ML.nH2O stoichiometry with either tetrahedral or octahedral geometry. The ESR data showed the Cu(II complex to be in a tetragonal geometry. Theoretical investigation of the electronic structure of metal complexes at the TD-DFT/B3LYP level of theory has been carried out and discussed. The fundamental vibrational wavenumbers were calculated and a good agreement between observed and scaled calculated wavenumbers was achieved. Thermal studies were performed to deduce the stabilities of the ligand and complexes. Thermodynamic parameters, such as the order of reactions (n, activation energy ΔE∗, enthalpy of reaction ΔH∗ and entropy ΔS∗ were calculated from DTA curves using Horowitz–Metzger method. The ligand L and its complexes have been screened for their antifungal and antibacterial activities and were found to possess better biological activities compared to those of unsubstituted barbituric acid complexes.

  17. Structural elucidation of the hormonal inhibition mechanism of the bile acid cholate on human carbonic anhydrase II

    Energy Technology Data Exchange (ETDEWEB)

    Boone, Christopher D. [University of Florida, PO Box 100267, Gainesville, FL 32610 (United States); Tu, Chingkuang [University of Florida, PO Box 100245, Gainesville, FL 32610 (United States); McKenna, Robert, E-mail: rmckenna@ufl.edu [University of Florida, PO Box 100267, Gainesville, FL 32610 (United States)

    2014-06-01

    The structure of human carbonic anhydrase II in complex with cholate has been determined to 1.54 Å resolution. Elucidation of the novel inhibition mechanism of cholate will aid in the development of a nonsulfur-containing, isoform-specific therapeutic agent. The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO{sub 2} into bicarbonate and a proton. Human isoform CA II (HCA II) is abundant in the surface epithelial cells of the gastric mucosa, where it serves an important role in cytoprotection through bicarbonate secretion. Physiological inhibition of HCA II via the bile acids contributes to mucosal injury in ulcerogenic conditions. This study details the weak biophysical interactions associated with the binding of a primary bile acid, cholate, to HCA II. The X-ray crystallographic structure determined to 1.54 Å resolution revealed that cholate does not make any direct hydrogen-bond interactions with HCA II, but instead reconfigures the well ordered water network within the active site to promote indirect binding to the enzyme. Structural knowledge of the binding interactions of this nonsulfur-containing inhibitor with HCA II could provide the template design for high-affinity, isoform-specific therapeutic agents for a variety of diseases/pathological states, including cancer, glaucoma, epilepsy and osteoporosis.

  18. RosettaTMH: a method for membrane protein structure elucidation combining EPR distance restraints with assembly of transmembrane helices

    Directory of Open Access Journals (Sweden)

    Andrew Leaver-Fay

    2015-12-01

    Full Text Available Membrane proteins make up approximately one third of all proteins, and they play key roles in a plethora of physiological processes. However, membrane proteins make up less than 2% of experimentally determined structures, despite significant advances in structure determination methods, such as X-ray crystallography, nuclear magnetic resonance spectroscopy, and cryo-electron microscopy. One potential alternative means of structure elucidation is to combine computational methods with experimental EPR data. In 2011, Hirst and others introduced RosettaEPR and demonstrated that this approach could be successfully applied to fold soluble proteins. Furthermore, few computational methods for de novo folding of integral membrane proteins have been presented. In this work, we present RosettaTMH, a novel algorithm for structure prediction of helical membrane proteins. A benchmark set of 34 proteins, in which the proteins ranged in size from 91 to 565 residues, was used to compare RosettaTMH to Rosetta’s two existing membrane protein folding protocols: the published RosettaMembrane folding protocol (“MembraneAbinitio” and folding from an extended chain (“ExtendedChain”. When EPR distance restraints are used, RosettaTMH+EPR outperforms ExtendedChain+EPR for 11 proteins, including the largest six proteins tested. RosettaTMH+EPR is capable of achieving native-like folds for 30 of 34 proteins tested, including receptors and transporters. For example, the average RMSD100SSE relative to the crystal structure for rhodopsin was 6.1 ± 0.4 Å and 6.5 ± 0.6 Å for the 449-residue nitric oxide reductase subunit B, where the standard deviation reflects variance in RMSD100SSE values across ten different EPR distance restraint sets. The addition of RosettaTMH and RosettaTMH+EPR to the Rosetta family of de novo folding methods broadens the scope of helical membrane proteins that can be accurately modeled with this software suite.

  19. Mass spectrometry for the elucidation of the subtle molecular structure of biodegradable polymers and their degradation products.

    Science.gov (United States)

    Kowalczuk, Marek; Adamus, Grażyna

    2016-01-01

    Contemporary reports by Polish authors on the application of mass spectrometric methods for the elucidation of the subtle molecular structure of biodegradable polymers and their degradation products will be presented. Special emphasis will be given to natural aliphatic (co)polyesters (PHA) and their synthetic analogues, formed through anionic ring-opening polymerization (ROP) of β-substituted β-lactones. Moreover, the application of MS techniques for the evaluation of the structure of biodegradable polymers obtained in ionic and coordination polymerization of cyclic ethers and esters as well as products of step-growth polymerization, in which bifunctional or multifunctional monomers react to form oligomers and eventually long chain polymers, will be discussed. Furthermore, the application of modern MS techniques for the assessment of polymer degradation products, frequently bearing characteristic end groups that can be revealed and differentiated by MS, will be discussed within the context of specific degradation pathways. Finally, recent Polish accomplishments in the area of mass spectrometry will be outlined. © 2015 Wiley Periodicals, Inc.

  20. Isolation and structure elucidation of avocado seed (Persea americana) lipid derivatives that inhibit Clostridium sporogenes endospore germination.

    Science.gov (United States)

    Rodríguez-Sánchez, Dariana Graciela; Pacheco, Adriana; García-Cruz, María Isabel; Gutiérrez-Uribe, Janet Alejandra; Benavides-Lozano, Jorge Alejandro; Hernández-Brenes, Carmen

    2013-07-31

    Avocado fruit extracts are known to exhibit antimicrobial properties. However, the effects on bacterial endospores and the identity of antimicrobial compounds have not been fully elucidated. In this study, avocado seed extracts were tested against Clostridium sporogenes vegetative cells and active endospores. Bioassay-guided purification of a crude extract based on inhibitory properties linked antimicrobial action to six lipid derivatives from the family of acetogenin compounds. Two new structures and four compounds known to exist in nature were identified as responsible for the activity. Structurally, most potent molecules shared features of an acetyl moiety and a trans-enone group. All extracts produced inhibition zones on vegetative cells and active endospores. Minimum inhibitory concentrations (MIC) of isolated molecules ranged from 7.8 to 15.6 μg/mL, and bactericidal effects were observed for an enriched fraction at 19.5 μg/mL. Identified molecules showed potential as natural alternatives to additives and antibiotics used by the food and pharmaceutical industries to inhibit Gram-positive spore-forming bacteria.

  1. Structure elucidation and toxicity analyses of the radiolytic products of aflatoxin B{sub 1} in methanol-water solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Graduate School of Chinese Academy of Agricultural Sciences, 12th Zhongguancun South Road, Hai Dian District, Beijing 100081 (China); Xie, Fang [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Xue, Xiaofeng [Bee Research Institute of Chinese Academy of Agricultural Sciences, 1st Xiangshan North Ditch, Hai Dian District, Beijing 100093 (China); Wang, Zhidong; Fan, Bei [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Ha, Yiming, E-mail: wxfay2011@hotmail.com [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China)

    2011-09-15

    Highlights: {yields} Radiolytic products of aflatoxin B{sub 1} were produced under gamma irradiation. {yields} Seven key radiolytic products were structure-elucidated. {yields} Free-radical species in radiolytic solution resulted in the formation of products. {yields} Based on the structure-activity relationship analysis, the toxicity of radiolytic products was significantly reduced compared with that of AFB{sub 1}. {yields} The addition reaction on furan ring double bond was the reason for the reduced toxicity. - Abstract: The identification of the radiolytic products of mycotoxins is a key issue in the feasibility study of gamma ray radiation detoxification. Methanol-water solution (60:40, v/v) spiked with aflatoxin B{sub 1} (AFB{sub 1}; 20 mg L{sup -1}) was irradiated with Co{sup 60} gamma ray to generate radiolytic products. Liquid chromatography-quadruple time-of-flight mass spectrometry was applied to identify the radiolytic products of AFB{sub 1}. Accurate mass and proposed molecular formulas with a high-matching property of more than 20 radiolytic products were obtained. Seven key radiolytic products were proposed based on the molecular formulas and tandem mass spectrometry spectra. The analyses of toxicity and formation pathways were proposed based on the structure of the radiolytic products. The addition reaction caused by the free-radical species in the methanol-water solution resulted in the formation of most radiolytic products. Based on the structure-activity relationship analysis, the toxicity of radiolytic products was significantly reduced compared with that of AFB{sub 1} because of the addition reaction that occurred on the double bond in the terminal furan ring. For this reason, gamma irradiation is deemed an effective tool for the detoxification of AFB{sub 1}.

  2. Purification and partial elucidation of the structure of an antioxidant carbohydrate biopolymer from the probiotic bacterium Bacillus coagulans RK-02.

    Science.gov (United States)

    Kodali, Vidya P; Perali, Ramu S; Sen, R

    2011-08-26

    An exopolysaccharide (EPS) was isolated from Bacillus coagulans RK-02 and purified by size exclusion chromatography. The purified, homogeneous EPS had an average molecular weight of ∼3 × 10⁴ Da by comparison with FITC-labeled dextran standards. In vivo evaluations showed that, like other reported polysaccharides, this EPS displayed significant antioxidant activity. FTIR spectroscopy analysis showed the presence of hydroxy, carboxy, and α-glycosidic linkages and a mannose residue. GC analysis indicated that the EPS was a heteropolymer composed of glucose, mannose, galactose, glucosamine, and fucose as monomeric constituent units. Partial elucidation of the structure of the carbohydrate biopolymer based on GC-MS and NMR analysis showed the presence of two unique sets of tetrasaccharide repeating units that have 1→3 and 1→6 glycosidic linkages. This is also the first report of a Gram-positive bacterial polysaccharide with both fucose as a sugar monomer and 1→3 and 1→6 glycosidic linkages in the molecular backbone.

  3. A comparative study of the DG-OMEGA (DG Omega), DGII, and GAT method for the structure elucidation of a methylene-acetal linked thymine dinucleotide

    NARCIS (Netherlands)

    van Kampen, A. H. C.; Beckers, M. L. M.; Buydens, L. M. C.

    1997-01-01

    This research continues the investigation of the properties of the recently developed structure elucidation method DG-OMEGA (DG Omega). Towards this end it was applied for the structure determination of a methylene-acetal linked thymine dinucleotide. The performance of DG Omega was compared to the

  4. Structure elucidation and in vitro cytotoxicity of ochratoxin α amide, a new degradation product of ochratoxin A.

    Science.gov (United States)

    Bittner, Andrea; Cramer, Benedikt; Harrer, Henning; Humpf, Hans-Ulrich

    2015-05-01

    The mycotoxin ochratoxin A is a secondary metabolite occurring in a wide range of commodities. During the exposure of ochratoxin A to white and blue light, a cleavage between the carbon atom C-14 and the nitrogen atom was described. As a reaction product, the new compound ochratoxin α amide has been proposed based on mass spectrometry (MS) experiments. In the following study, we observed that this compound is also formed at high temperatures such as used for example during coffee roasting and therefore represents a further thermal ochratoxin A degradation product. To confirm the structure of ochratoxin α amide, the compound was prepared in large scale and complete structure elucidation via nuclear magnetic resonance (NMR) and MS was performed. Additionally, first studies on the toxicity of ochratoxin α amide were performed using immortalized human kidney epithelial (IHKE) cells, a cell line known to be sensitive against ochratoxin A with an IC50 value of 0.5 μM. Using this system, ochratoxin α amide revealed no cytotoxicity up to concentrations of 50 μM. Thus, these results propose that the thermal degradation of ochratoxin A to ochratoxin α amide might be a detoxification process. Finally, we present a sample preparation and a HPLC-tandem mass spectrometry (HPLC-MS/MS) method for the analysis of ochratoxin α amide in extrudates and checked its formation during the extrusion of artificially contaminated wheat grits at 150 and 180 °C, whereas no ochratoxin α amide was detectable under these conditions.

  5. Structural–Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work

    Directory of Open Access Journals (Sweden)

    Gerd Krause

    2017-04-01

    Full Text Available The thyroid-stimulating hormone receptor (TSHR is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs. TSHR and its endogenous ligand thyrotropin (TSH are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016 concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other

  6. Structural–Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work

    Science.gov (United States)

    Kleinau, Gunnar; Worth, Catherine L.; Kreuchwig, Annika; Biebermann, Heike; Marcinkowski, Patrick; Scheerer, Patrick; Krause, Gerd

    2017-01-01

    The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to

  7. Structure Elucidation of A New Coumarin Type Compound, Alternamin, Isolated from the Plant (Murraya Alternans (Kurz) Swingle) Having The Antidote Activity on Snake Venoms

    International Nuclear Information System (INIS)

    Hla Myo Min; Mya Aye

    2004-06-01

    The structure of a new coumarin type compound isolated from the entitled species was elucidated by the full spectral analysis consisting of FTIR, 1H NMR, DQF COSY, 13C NMR, DEPT, EIMS (HR-EIMS), HMQC and HMBC. The antidote activities of the fresh juice and the ethanolic extract of the plant, and the isolated compound alternamin were also determined

  8. Monoclonal Antibodies to the Thyrotropin Receptor

    Directory of Open Access Journals (Sweden)

    Takao Ando

    2005-01-01

    Full Text Available The thyrotropin receptor (TSHR is a seven transmembrane G-protein linked glycoprotein expressed on the thyroid cell surface and which, under the regulation of TSH, controls the production and secretion of thyroid hormone from the thyroid gland. This membrane protein is also a major target antigen in the autoimmune thyroid diseases. In Graves' disease, autoantibodies to the TSHR (TSHR-Abs stimulate the TSHR to produce thyroid hormone excessively. In autoimmune thyroid failure, some patients exhibit TSHR-Abs which block TSH action on the receptor. There have been many attempts to generate human stimulating TSHR-mAbs, but to date, only one pathologically relevant human stimulating TSHR-mAb has been isolated. Most mAbs to the TSHR have been derived from rodents immunized with TSHR antigen from bacteria or insect cells. These antigens lacked the native conformation of the TSHR and the resulting mAbs were exclusively blocking or neutral TSHR-mAbs. However, mAbs raised against intact native TSHR antigen have included stimulating mAbs. One such stimulating mAb has demonstrated a number of differences in its regulation of TSHR post-translational processing. These differences are likely to be reflective of TSHR-Abs seen in Graves' disease.

  9. Effect of gamma irradiation on biological activity of thyrotropin

    Energy Technology Data Exchange (ETDEWEB)

    Strbak, V; Macho, L; Sedlak, J; Hromadova, M

    1976-03-01

    The biological activity of thyrotropin (TSH) was tested after sterilization by 0.5 and 12.5 Mrad of gamma irradiation. It was found that the biological activity (McKenzie's assay) of TSH irradiated in dry state was not affected during the first month after sterilization by doses of 0.5 and 2.5 Mrad. However, substantial decrease of TSH biological activity was observed 3 to 5 months after the irradiation, the lower activity being after the former dose. The irradiation of TSH by 12.5 Mrad in dry state and by 0.5 and 2.5 Mrad in solution resulted in a decrease of biological activity already during first month. The structural changes in the molecule of TSH were apparently not very extensive, since a decrease of disulfide bonds from 0.96 to 0.77 M per 1M of TSH was found immediately after the irradiation, while uv absorbancy and electrophoretic mobility on polyacrylamide gel electrophoresis were unaffected. These changes were followed by the decrease of TSH stability during storage in dry state. It is hypothesized that TSH molecule may be affected in ..beta.. subunit or in its connection with ..cap alpha...

  10. Effect of gamma irradiation on biological activity of thyrotropin

    International Nuclear Information System (INIS)

    Strbak, V.; Macho, L.; Sedlak, J.; Hromadova, M.

    1976-01-01

    The biological activity of thyrotropin (TSH) was tested after sterilization by 0.5 and 12.5 Mrad of gamma radiation. It was found that the biological activity (McKenzie's assay) of TSH irradiated in dry state was not affected during the first month after sterilization by doses of 0.5 and 2.5 Mrad. However, substantial decrease of TSH biological activity was observed 3 to 5 months after the irradiation, the lower activity after the 0.5 Mrad dose. The irradiation of TSH by 12.5 Mrad in dry state and by 0.5 and 2.5 Mrad in solution resulted in decreased biological activity already during the first month. The structural changes in the TSH molecule were apparently not very extensive, as a decrease of disulfide bonds from 0.96 to 0.77 M per 1 M of TSH was found immediately after the irradiation, while UV absorbancy and electrophoretic mobility on polyacrylamide gel electrophoresis were unaffected. These changes were followed by a decrease of TSH stability during storage in dry state. It is hypothesized that a TSH molecule may be affected in a β subunit or in its connection with α. (author)

  11. Elucidation of the structure-property relationship of p-type organic semiconductors through rapid library construction via a one-pot, Suzuki-Miyaura coupling reaction.

    Science.gov (United States)

    Fuse, Shinichiro; Matsumura, Keisuke; Wakamiya, Atsushi; Masui, Hisashi; Tanaka, Hiroshi; Yoshikawa, Susumu; Takahashi, Takashi

    2014-09-08

    The elucidation of the structure-property relationship is an important issue in the development of organic electronics. Combinatorial synthesis and the evaluation of systematically modified compounds is a powerful tool in the work of elucidating structure-property relationships. In this manuscript, D-π-A structure, 32 p-type organic semiconductors were rapidly synthesized via a one-pot, Suzuki-Miyaura coupling with subsequent Knoevenagel condensation. Evaluation of the solubility and photovoltaic properties of the prepared compounds revealed that the measured solubility was strongly correlated with the solubility parameter (SP), as reported by Fedors. In addition, the SPs were correlated with the Jsc of thin-film organic solar cells prepared using synthesized compounds. Among the evaluated photovoltaic properties of the solar cells, Jsc and Voc had strong correlations with the photoconversion efficiency (PCE).

  12. The thyroid nodule. Thyrotropin and peripheral thyroid hormones

    International Nuclear Information System (INIS)

    Zimny, M.

    2008-01-01

    Thyrotropin, free triodothyronine and thyroxine represent the standard serological parameters for the diagnostic work-up of the thyroid but only a minority of thyroid nodules present with subclinical or overt thyroid disorders. Besides a review of the regulation and principle of function of thyroid hormones as well as the effects of subclinical or overt hyperthyroidism, the significant role of these parameters beyond the assessment of hyperthyroidism in thyroid nodules is discussed. There is evidence that the level of thyrotropin within the normal range is predictive for the relevance of autonomous functioning nodules and the risk of malignancy of non-functioning thyroid nodules. Furthermore, the ratio of triodothyronine and thyroxine indicates the etiology of hyperthyroidism. Thyrotropin represents the main parameter to determine the adequate dose of thyroid hormone therapy of thyroid nodules. (orig.)

  13. LC-MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products

    Energy Technology Data Exchange (ETDEWEB)

    Slegers, Catherine [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium)]. E-mail: catherine.slegers@skynet.be; Maquille, Aubert [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium); Deridder, Veronique [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium); Sonveaux, Etienne [Unite de Chimie Pharmaceutique et de Radiopharmacie, Universite Catholique de Louvain, Brussels (Belgium); Habib Jiwan, Jean-Louis [Laboratoire de Spectrometrie de Masse, Universite Catholique de Louvain, Louvain-La-Neuve (Belgium); Tilquin, Bernard [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium)

    2006-09-15

    E-beam and gamma products from the radiolysis of aqueous solutions of ({+-})-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of ({+-})-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

  14. LC-MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products

    International Nuclear Information System (INIS)

    Slegers, Catherine; Maquille, Aubert; Deridder, Veronique; Sonveaux, Etienne; Habib Jiwan, Jean-Louis; Tilquin, Bernard

    2006-01-01

    E-beam and gamma products from the radiolysis of aqueous solutions of (±)-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of (±)-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed

  15. Fourth ventricular thyrotropin induces satiety and increases body temperature in rats.

    Science.gov (United States)

    Smedh, Ulrika; Scott, Karen A; Moran, Timothy H

    2018-05-01

    Besides its well-known action to stimulate thyroid hormone release, thyrotropin mRNA is expressed within the brain, and thyrotropin and its receptor have been shown to be present in brain areas that control feeding and gastrointestinal function. Here, the hypothesis that thyrotropin acts on receptors in the hindbrain to alter food intake and/or gastric function was tested. Fourth ventricular injections of thyrotropin (0.06, 0.60, and 6.00 µg) were given to rats with chronic intracerebroventricular cannulas aimed at the fourth ventricle. Thyrotropin produced an acute reduction of sucrose intake (30 min). The highest dose of thyrotropin caused inhibition of overnight solid food intake (22 h). In contrast, subcutaneous administration of corresponding thyrotropin doses had no effect on nutrient intake. The highest effective dose of fourth ventricular thyrotropin (6 µg) did not produce a conditioned flavor avoidance in a standardized two-bottle test, nor did it affect water intake or gastric emptying of glucose. Thyrotropin injected in the fourth ventricle produced a small but significant increase in rectal temperature and lowered plasma levels of tri-iodothyronin but did not affect plasma levels of thyroxine. In addition, there was a tendency toward a reduction in blood glucose 2 h after fourth ventricular thyrotropin injection ( P = 0.056). In conclusion, fourth ventricular thyrotropin specifically inhibits food intake, increases core temperature, and lowers plasma levels of tri-iodothyronin but does not affect gastromotor function.

  16. Pulsatile thyrotropin secretion in patients with Cushing's syndrome

    NARCIS (Netherlands)

    Adriaanse, R.; Brabant, G.; Endert, E.; Wiersinga, W. M.

    1994-01-01

    Pulsatile and circadian thyrotropin (TSH) secretion were studied in 16 healthy controls and in three patients with Cushing's syndrome who were studied twice (before and after treatment). Blood was sampled every 10 minutes over 24 hours for TSH (immunoradiometric assay [IRMA]). Mean 24-hour TSH in

  17. Preparation of standards of triiodothyronine, thyroxine and thyrotropin

    International Nuclear Information System (INIS)

    Lavalley E, C.; Delgado S, B.; Ruiz J, A.; Zambrano A, F.

    1991-10-01

    The standards preparation requires of certain basic principles, some of which are described in this work, which was made with the purpose of establishing the most appropriate conditions for the preparation of standards of triiodothyronine, thyroxine and thyrotropin to be used in radioimmunoanalysis essays. The diverse standards show a balanced displacement, that which is observed in the graphs presented in this work. (Author)

  18. Serum Levels of Thyroid Hormones and Thyrotropin in Some Sickle ...

    African Journals Online (AJOL)

    The serum levels of the thyroid hormones (T4 and T3) and thyrotropin (TSH) were measured by radio-immunoassay (RIA) in the steady state of 10 homozygous sickle cell anaemia patients and 10 normal subjects of the same age group in years (15-25) who were the control group. The results showed that sickle cell disease ...

  19. Mutations that silence constitutive signaling activity in the allosteric ligand-binding site of the thyrotropin receptor.

    Science.gov (United States)

    Haas, Ann-Karin; Kleinau, Gunnar; Hoyer, Inna; Neumann, Susanne; Furkert, Jens; Rutz, Claudia; Schülein, Ralf; Gershengorn, Marvin C; Krause, Gerd

    2011-01-01

    The thyrotropin receptor (TSHR) exhibits elevated cAMP signaling in the basal state and becomes fully activated by thyrotropin. Previously we presented evidence that small-molecule ligands act allosterically within the transmembrane region in contrast to the orthosteric extracellular hormone-binding sites. Our goal in this study was to identify positions that surround the allosteric pocket and that are sensitive for inactivation of TSHR. Homology modeling combined with site-directed mutagenesis and functional characterization revealed seven mutants located in the allosteric binding site that led to a decrease of basal cAMP signaling activity. The majority of these silencing mutations, which constrain the TSHR in an inactive conformation, are found in two clusters when mapped onto the 3D structural model. We suggest that the amino acid positions identified herein are indicating locations where small-molecule antagonists, both neutral antagonists and inverse agonists, might interfere with active TSHR conformations.

  20. Organic-Silica Interactions in Saline: Elucidating the Structural Influence of Calcium in Low-Salinity Enhanced Oil Recovery.

    Science.gov (United States)

    Desmond, J L; Juhl, K; Hassenkam, T; Stipp, S L S; Walsh, T R; Rodger, P M

    2017-09-08

    Enhanced oil recovery using low-salinity solutions to sweep sandstone reservoirs is a widely-practiced strategy. The mechanisms governing this remain unresolved. Here, we elucidate the role of Ca 2+ by combining chemical force microscopy (CFM) and molecular dynamics (MD) simulations. We probe the influence of electrolyte composition and concentration on the adsorption of a representative molecule, positively-charged alkylammonium, at the aqueous electrolyte/silica interface, for four electrolytes: NaCl, KCl, MgCl 2 , and CaCl 2 . CFM reveals stronger adhesion on silica in CaCl 2 compared with the other electrolytes, and shows a concentration-dependent adhesion not observed for the other electrolytes. Using MD simulations, we model the electrolytes at a negatively-charged amorphous silica substrate and predict the adsorption of methylammonium. Our simulations reveal four classes of surface adsorption site, where the prevalence of these sites depends only on CaCl 2 concentration. The sites relevant to strong adhesion feature the O - silica site and Ca 2+ in the presence of associated Cl - , which gain prevalence at higher CaCl 2 concentration. Our simulations also predict the adhesion force profile to be distinct for CaCl 2 compared with the other electrolytes. Together, these analyses explain our experimental data. Our findings indicate in general how silica wettability may be manipulated by electrolyte concentration.

  1. Structural Elucidation of Z- and E- Isomers of 5-Alkyl-4-ethoxycarbonyl-5-(4`-chlorophenyl-3-oxa-4-pentenoic Acids

    Directory of Open Access Journals (Sweden)

    H. M. F. Madkour

    2000-05-01

    Full Text Available Z- and E-isomers of 5-alkyl-4-ethoxycarbonyl-5-(4`-chlorophenyl-3-oxa-4-pentenoic acids were prepared via the condensation of p-chloroacetophenone and/or pchloropropiophenone with diethyl-2,2`-oxydiacetate in the presence of sodium hydride as a basic catalyst. The Z-isomers of 2a and 2b were found to be predominant. The behaviour of the corresponding anhydrides towards the action of hydrazine, phenylhydrazine, primary aromatic amines, hydrocarbons and ethanolysis has also been investigated. The structures and configurations of the products have been elucidated by chemical and spectroscopic means.

  2. Effect of primary particle size on spray formation, morphology and internal structure of alumina granules and elucidation of flowability and compaction behaviour

    Directory of Open Access Journals (Sweden)

    Pandu Ramavath

    2014-06-01

    Full Text Available Three different alumina powders with varying particle sizes were subjected to spray drying under identical conditions and effect of particle size on heat transfer efficiency and mechanism of formation of granules was elucidated. Morphology, internal structure and size distribution of granules were studied and evaluated with respect to their flow behaviour. In order to estimate the elastic interaction of granules, the granules were subjected to compaction under progressive loading followed by periodic unloading. Compaction curves were plotted and compressibility factor was estimated and correlated with predicted and measured green density values.

  3. High-performance liquid chromatography on-line coupled to high-field NMR and mass spectrometry for structure elucidation of constituents of Hypericum perforatum L

    DEFF Research Database (Denmark)

    Hansen, S. H.; Jensen, A. G.; Cornett, Claus

    1999-01-01

    The on-line separation and structure elucidation of naphthodianthrones, flavonoids, and other constituents of an extract from Hypericum perforatum L, using high performance liquid chromatography (HPLC) coupled on-line with ultraviolet-visible, nuclear magnetic resonance (NMR), and mass spectrometry...... (MS) is described. A conventional reversed-phase HPLC system using ammonium acetate as the buffer substance in the eluent tvas used, and proton NMR spectra were obtained on a 500 MHz NMR instrument. The MS and MS/MS analyses were performed using negative electrospray ionization, In the present study...

  4. Exploiting the Complementarity between Dereplication and Computer-Assisted Structure Elucidation for the Chemical Profiling of Natural Cosmetic Ingredients: Tephrosia purpurea as a Case Study.

    Science.gov (United States)

    Hubert, Jane; Chollet, Sébastien; Purson, Sylvain; Reynaud, Romain; Harakat, Dominique; Martinez, Agathe; Nuzillard, Jean-Marc; Renault, Jean-Hugues

    2015-07-24

    The aqueous-ethanolic extract of Tephrosia purpurea seeds is currently exploited in the cosmetic industry as a natural ingredient of skin lotions. The aim of this study was to chemically characterize this ingredient by combining centrifugal partition extraction (CPE) as a fractionation tool with two complementary identification approaches involving dereplication and computer-assisted structure elucidation. Following two rapid fractionations of the crude extract (2 g), seven major compounds namely, caffeic acid, quercetin-3-O-rutinoside, ethyl galactoside, ciceritol, stachyose, saccharose, and citric acid, were unambiguously identified within the CPE-generated simplified mixtures by a recently developed (13)C NMR-based dereplication method. The structures of four additional compounds, patuletin-3-O-rutinoside, kaempferol-3-O-rutinoside, guaiacylglycerol 8-vanillic acid ether, and 2-methyl-2-glucopyranosyloxypropanoic acid, were automatically elucidated by using the Logic for Structure Determination program based on the interpretation of 2D NMR (HSQC, HMBC, and COSY) connectivity data. As more than 80% of the crude extract mass was characterized without need for tedious and labor-intensive multistep purification procedures, the identification tools involved in this work constitute a promising strategy for an efficient and time-saving chemical profiling of natural extracts.

  5. Heparin sodium compliance to USP monograph: structural elucidation of an atypical 2.18 ppm NMR signal.

    Science.gov (United States)

    Mourier, Pierre A J; Guichard, Olivier Y; Herman, Fréderic; Viskov, Christian

    2012-01-01

    The ¹H nuclear magnetic resonance (NMR) acceptance criteria in the new heparin US Pharmacopeia (USP) monograph do not take into account potential structural modifications responsible for any extra signals observed in ¹H NMR spectra, some purified heparins may be non-compliant under the proposed new USP guidelines and incorrectly classified as unsuitable for pharmaceutical use. Heparins from the "ES" source, containing an extra signal at 2.18 ppm, were depolymerized under controlled conditions using heparinases I, II, and III. The oligosaccharides responsible for the 2.18 ppm signal were enriched using orthogonal chromatographic techniques. After multiple purification steps, we obtained an oligosaccharide mixture containing a highly enriched octasaccharide bearing the structural modification responsible for the extra signal. Following heparinase I depolymerization, a pure tetrasaccharide containing the fingerprint structural modification was isolated for full structural determination. Using 1D and 2D ¹H NMR spectroscopy, the structural moiety responsible for the extra signal at 2.18 ppm was identified as an acetyl group on the heparin backbone, most likely resulting from a very minor manufacturing process side reaction that esterifies the uronic acid at position 3. Such analytical peculiarity has always been present in this heparin source and it was used safety over the years. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Elucidation of the structure of organic solutions in solvent extraction by combining molecular dynamics and X-ray scattering

    International Nuclear Information System (INIS)

    Ferru, G.; Gomes Rodrigues, D.; Berthon, L.; Guilbaud, P.; Diat, O.; Bauduin, P.

    2014-01-01

    Knowledge of the supramolecular structure of the organic phase containing amphiphilic ligand molecules is mandatory for full comprehension of ionic separation during solvent extraction. Existing structural models are based on simple geometric aggregates, but no consensus exists on the interaction potentials. Herein, we show that molecular dynamics crossed with scattering techniques offers key insight into the complex fluid involving weak interactions without any long range ordering. Two systems containing mono- or diamide extractants in heptane and contacted with an aqueous phase were selected as examples to demonstrate the advantages of coupling the two approaches for furthering fundamental studies on solvent extraction. (authors)

  7. Structural elucidation of the DFG-Asp in and DFG-Asp out states of TAM kinases and insight into the selectivity of their inhibitors.

    Science.gov (United States)

    Messoussi, Abdellah; Peyronnet, Lucile; Feneyrolles, Clémence; Chevé, Gwénaël; Bougrin, Khalid; Yasri, Aziz

    2014-10-10

    Structural elucidation of the active (DFG-Asp in) and inactive (DFG-Asp out) states of the TAM family of receptor tyrosine kinases is required for future development of TAM inhibitors as drugs. Herein we report a computational study on each of the three TAM members Tyro-3, Axl and Mer. DFG-Asp in and DFG-Asp out homology models of each one were built based on the X-ray structure of c-Met kinase, an enzyme with a closely related sequence. Structural validation and in silico screening enabled identification of critical amino acids for ligand binding within the active site of each DFG-Asp in and DFG-Asp out model. The position and nature of amino acids that differ among Tyro-3, Axl and Mer, and the potential role of these residues in the design of selective TAM ligands, are discussed.

  8. Structural Elucidation of the DFG-Asp in and DFG-Asp out States of TAM Kinases and Insight into the Selectivity of Their Inhibitors

    Directory of Open Access Journals (Sweden)

    Abdellah Messoussi

    2014-10-01

    Full Text Available Structural elucidation of the active (DFG-Asp in and inactive (DFG-Asp out states of the TAM family of receptor tyrosine kinases is required for future development of TAM inhibitors as drugs. Herein we report a computational study on each of the three TAM members Tyro-3, Axl and Mer. DFG-Asp in and DFG-Asp out homology models of each one were built based on the X-ray structure of c-Met kinase, an enzyme with a closely related sequence. Structural validation and in silico screening enabled identification of critical amino acids for ligand binding within the active site of each DFG-Asp in and DFG-Asp out model. The position and nature of amino acids that differ among Tyro-3, Axl and Mer, and the potential role of these residues in the design of selective TAM ligands, are discussed.

  9. Structural elucidation of dendritic host-guest complexes by X-ray crystallography and molecular dynamics simulations

    NARCIS (Netherlands)

    Chang, T.; Pieterse, K.; Broeren, M.A.C.; Kooijman, H.; Spek, A.L.; Hilbers, P.A.J.; Meijer, E.W.

    2007-01-01

    The multiple monovalent binding of adamantyl-urea poly(propyleneimine) dendrimers with carboxylic acid-urea guests was investigated using molecular dynamics simulations and X-ray crystallography to better understand the structure and behavior of the dynamic multivalent complex in solution. The

  10. Structural Elucidation and Biological Activity of a Highly Regular Fucosylated Glycosaminoglycan from the Edible Sea Cucumber Stichopus herrmanni.

    Science.gov (United States)

    Li, Xiaomei; Luo, Lan; Cai, Ying; Yang, Wenjiao; Lin, Lisha; Li, Zi; Gao, Na; Purcell, Steven W; Wu, Mingyi; Zhao, Jinhua

    2017-10-25

    Edible sea cucumbers are widely used as a health food and medicine. A fucosylated glycosaminoglycan (FG) was purified from the high-value sea cucumber Stichopus herrmanni. Its physicochemical properties and structure were analyzed and characterized by chemical and instrumental methods. Chemical analysis indicated that this FG with a molecular weight of ∼64 kDa is composed of N-acetyl-d-galactosamine, d-glucuronic acid (GlcA), and l-fucose. Structural analysis clarified that the FG contains the chondroitin sulfate E-like backbone, with mostly 2,4-di-O-sulfated (85%) and some 3,4-di-O-sulfated (10%) and 4-O-sulfated (5%) fucose side chains that link to the C3 position of GlcA. This FG is structurally highly regular and homogeneous, differing from the FGs of other sea cucumbers, for its sulfation patterns are simpler. Biological activity assays indicated that it is a strong anticoagulant, inhibiting thrombin and intrinsic factor Xase. Our results expand the knowledge on structural types of FG and illustrate its biological activity as a functional food material.

  11. Insights into structural features of HDAC1 and its selectivity inhibition elucidated by Molecular dynamic simulation and Molecular Docking.

    Science.gov (United States)

    Sixto-López, Yudibeth; Bello, Martiniano; Correa-Basurto, José

    2018-03-06

    Histone deacetylases (HDACs) are a family of proteins whose main function is the removal of acetyl groups from lysine residues located on histone and non-histone substrates, which regulates gene transcription and other activities in cells. HDAC1 dysfunction has been implicated in cancer development and progression; thus, its inhibition has emerged as a new therapeutic strategy. Two additional metal binding sites (Site 1 and Site 2) in HDACs have been described that are primarily occupied by potassium ions, suggesting a possible structural role that affects HDAC activity. In this work, we explored the structural role of potassium ions in Site 1 and Site 2 and how they affect the interactions of compounds with high affinities for HDAC1 (AC1OCG0B, Chlamydocin, Dacinostat and Quisinostat) and SAHA (a pan-inhibitor) using molecular docking and molecular dynamics (MD) simulations in concert with a Molecular-Mechanics-Generalized-Born-Surface-Area (MMGBSA) approach. Four models were generated: one with a potassium ion (K + ) in both sites (HDAC1 k ), a second with K + only at site 1 (HDAC1 ks1 ), a third with K + only at site 2 (HDAC1 ks2 ) and a fourth with no K + (HDAC1 wk ). We found that the presence or absence of K + not only impacted the structural flexibility of HDAC1, but also its molecular recognition, consistent with experimental findings. These results could therefore be useful for further structure-based drug design studies addressing new HDAC1 inhibitors.

  12. Activating thyrotropin receptor mutations in histologically heterogeneous hyperfunctioning nodules of multinodular goiter.

    Science.gov (United States)

    Tonacchera, M; Vitti, P; Agretti, P; Giulianetti, B; Mazzi, B; Cavaliere, R; Ceccarini, G; Fiore, E; Viacava, P; Naccarato, A; Pinchera, A; Chiovato, L

    1998-07-01

    Activating thyrotropin (TSH) receptor mutations have been found in toxic adenomas and in hot nodules contained in toxic multinodular goiter. The typical feature of multinodular goiter is the heterogeneity in morphology and function of different follicles within the same enlarged gland. In this report we describe a patient with a huge multinodular goiter, normal free triiodothyronine (FT3) and free thyroxine (FT4) serum values, and subnormal TSH serum concentration. Thyroid scintiscan showed two hot areas corresponding to the basal and apical nodules of the left lobe. The right lobe was poorly visualized by the radioisotope. The patient underwent thyroidectomy, and histological examination of the tissue was performed. Genomic DNA was extracted from the tissue specimen and direct sequencing of the TSH receptor and Gs alpha genes was done. At histology, one hyperfunctioning nodule had the typical microscopic structure of thyroid adenomas, and the other contained multiple macrofollicular areas not confined by a capsule. In spite of this histological difference, both hyperfunctioning nodules harbored a mutation of the thyrotropin receptor (TSHr) gene: an isoleucine instead of a threonine in position 632 (T632I) in the first nodule and a methionine instead of an isoleucine in position 486 (I486M) in the second nodule. In conclusion, our findings show for the first time that gain-of-function TSHr mutations are not only present in hyperfunctioning thyroid nodules with the histological features of the true thyroid adenomas, but also in hyperfunctioning hyperplastic nodules contained in the same multinodular goiter.

  13. Predictions of flavonoid solubility in ionic liquids by COSMO-RS: experimental verification, structural elucidation, and solvation characterization

    DEFF Research Database (Denmark)

    Guo, Zheng; Lue, Bena-Marie; Thomsen, Kaj

    2007-01-01

    Predictions of the solubility of flavonoids in a large variety of ionic liquids (ILs) with over 1800 available structures were examined based on COSMO-RS computation. The results show that the solubilities of flavonoids are strongly anion-dependent. Experimental measurement of the solubilities...... of esculin and rutin in 12 ILs with varying anions and cations show that predicted and experimental results generally have a good agreement. Based on the sound physical basis of COSMO-RS, the solubility changes of flavonoids were quantitatively associated with solvation interactions and structural...... characteristics of ILs. COSMO-RS derived parameters, i.e. misfit, H-bonding and van der Waals interaction energy, are shown to be capable of characterizing the complicated multiple interactions in the IL system effectively. H-bonding interaction is the most dominant interaction for ILs (followed by misfit and van...

  14. Isolation and structure elucidation of neuropeptides of the AKH/RPCH family in long-horned grasshoppers (Ensifera).

    Science.gov (United States)

    Gäde, G

    1992-11-01

    An identical neuropeptide was isolated by reversed-phase high-performance liquid chromatography from the corpora cardiaca of the king cricket, Libanasidus vittatus, and the two armoured ground crickets, Heterodes namaqua and Acanthoproctus cervinus. The crude gland extracts had adipokinetic activity in migratory locusts, hypertrehalosaemic activity in American cockroaches and a slight hypertrehalosaemic, but no adipokinetic, effect in armoured ground crickets. The primary structure of this neuropeptide was determined by pulsed-liquid phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal 5-oxopyrrolidine-2-carboxylic acid residue. The C-terminus was also blocked, as indicated by the lack of digestion by carboxypeptidase A. The peptide was assigned the structure [symbol: see text]Glu-Leu-Asn-Phe-Ser-Thr-Gly-TrpNH2, previously designated Scg-AKH-II. The corpora cardiaca of the cricket Gryllodes sigillatus contained a neuropeptide which differed in retention time from the one isolated from the king and armoured ground crickets. The structure was assigned as [symbol: see text]Glu-Val-Asn-Phe-Ser-Thr-Gly-TrpNH2, previously designated Grb-AKH. This octapeptide caused hyperlipaemia in its donor species. The presence of the same peptide, Scg-AKH-II, in the two primitive infraorders of Ensifera, and the different peptide, Grb-AKH, in the most advanced infraorder of Ensifera, supports the evolutionary trends assigned formerly from morphological and physiological evidence.

  15. Study on the Reactivity of Amino Acid Chemosensor, NPFNP, with Ethanol: Structural Elucidation through Single Crystal XRD and DFT Calculations

    Directory of Open Access Journals (Sweden)

    Beena Varghese

    2017-01-01

    Full Text Available A novel ethoxy derivative of an amino acid chemosensor, 3-naphthyl-1-phenyl-5-(2ʹ-fluoro-5ʹ-nitrophenyl-2-pyrazoline (NPFNP, has been synthesized and characterized by different spectroscopic methods.  A single crystal of the ethoxy derivative, 3-naphthyl-1-phenyl-5-(2ʹ-ethoxy-5ʹ-nitrophenyl-2-pyrazoline NPENP, has been obtained and characterized.  The structure holds interest as it carries biologically active pyrazoline as a central ring attaching to electron donating and withdrawing substituents. The major motivation for this work was to gain detailed insight into the structural parameters of this compound for investigating the influence of crystal packing and geometrical dimensions on optical properties. Time-dependent DFT calculations have been employed for comparing the XRD data with theoretical parameters. The results show that the DFT method at B3LYP/6-31G level can well reproduce the structure of the title compound.

  16. Porphyrins from Messel oil shale (Eocene, Germany): Structure elucidation, geochemical and biological significance, and distribution as a function of depth

    Energy Technology Data Exchange (ETDEWEB)

    Ocampo, R.; Bauder, C.; Callot, H.J.; Albrecht, P. (Univ. Louis Pasteur, Strasbourg (France))

    1992-02-01

    The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry, and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3), and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical Treibs scheme,' including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d, homolog pairs of porphyrins (3-H/3-ethyl), etc.

  17. Porphyrins from Messel oil shale (Eocene, Germany): Structure elucidation, geochemical and biological significance, and distribution as a function of depth

    Science.gov (United States)

    Ocampo, Rubén; Bauder, Claude; Callot, Henry J.; Albrecht, Pierre

    1992-02-01

    The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3) and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical "Treibs scheme," including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d, homolog pairs of porphyrins (3-H/3-ethyl), etc.

  18. Structural elucidation, molecular representation and solvent interactions of vitrinite-rich and inertinite-rich South African coals

    Science.gov (United States)

    van Niekerk, Daniel

    The structural differences and similarities of two Permian-aged South African coals, vitrinite-rich Waterberg and inertinite-rich Highveld coals (similar rank, carbon content and Permian age), were evaluated. With South African coals the opportunity presented itself to study not only Permian-aged Gondwana vitrinite but also inertinite. It was expected that these coals would differ from Northern hemisphere Carboniferous coals. It was concluded from various structural data that both coals, although different in maceral composition and depositional basins, are similar in their base structural composition. The main differences were that the inertinite-rich Highveld coal was more ordered, more aromatic, and had less hydrogen than the vitrinite-rich Waterberg coal. Analytical data were used to construct large-scale advanced molecular representations for vitrinite-rich Waterberg and inertinite-rich Highveld coals. The three-dimensional models were structurally diverse with a molecular weight range of 78 to 1900 amu. The vitrinite-rich coal model consisted of 18,572 atoms and 191 individual molecules and the inertinite-rich coal model consisted of 14,242 atoms and 158 individual molecules. This largescale modeling effort was enabled by the development of various PERL scripts to automate various visualization and analytical aspects. Coal swelling studies were conducted using the traditional pack-bed swelling method and a new novel single-particle stop-motion videography swelling method with NMP and CS2/NMP solvents. The pack-bed swelling showed that vitrinite-rich coal had a greater swelling extent and that swelling extent for both coals was greater in CS2/NMP binary solvent than for NMP. Single-particle swelling experiments showed that both coals, for both solvents, exhibit overshoot-type and climbing-type swelling behaviors. Inertinite-coal had a faster swelling rate, in both solvents, than the vitrinite-rich coal. The single-particle swelling data was used to calculate

  19. A SARS-coronovirus 3CL protease inhibitor isolated from the marine sponge Axinella cf. corrugata: structure elucidation and synthesis

    International Nuclear Information System (INIS)

    Lira, Simone P. de; Seleghim, Mirna H.R.; Berlinck, Roberto G.S.

    2007-01-01

    Two coumarin derivatives, esculetin-4-carboxylic acid methyl ester (1) and esculetin-4- carboxylic acid ethyl ester (2), have been isolated from the marine sponge Axinella cf. corrugata. Structure determination included analysis of spectroscopic data and total synthesis of compound 2. These are the first coumarin derivatives isolated from a marine sponge. The ethyl ester 2 was found to be an in vitro inhibitor of SARS 3CL-protease and an effective inhibitor of SARS-CoV replication in Vero cells at non-cytotoxic concentrations. (author)

  20. Structural Elucidation of Metabolites of Synthetic Cannabinoid UR-144 by Cunninghamella elegans Using Nuclear Magnetic Resonance (NMR) Spectroscopy.

    Science.gov (United States)

    Watanabe, Shimpei; Kuzhiumparambil, Unnikrishnan; Fu, Shanlin

    2018-03-08

    The number of new psychoactive substances keeps on rising despite the controlling efforts by law enforcement. Although metabolism of the newly emerging drugs is continuously studied to keep up with the new additions, the exact structures of the metabolites are often not identified due to the insufficient sample quantities for techniques such as nuclear magnetic resonance (NMR) spectroscopy. The aim of the study was to characterise several metabolites of the synthetic cannabinoid (1-pentyl-1H-indol-3-yl) (2,2,3,3-tetramethylcyclopropyl) methanone (UR-144) by NMR spectroscopy after the incubation with the fungus Cunninghamella elegans. UR-144 was incubated with C. elegans for 72 h, and the resulting metabolites were chromatographically separated. Six fractions were collected and analysed by NMR spectroscopy. UR-144 was also incubated with human liver microsomes (HLM), and the liquid chromatography-high resolution mass spectrometry analysis was performed on the HLM metabolites with the characterised fungal metabolites as reference standards. Ten metabolites were characterised by NMR analysis including dihydroxy metabolites, carboxy and hydroxy metabolites, a hydroxy and ketone metabolite, and a carboxy and ketone metabolite. Of these metabolites, dihydroxy metabolite, carboxy and hydroxy metabolites, and a hydroxy and ketone metabolite were identified in HLM incubation. The results indicate that the fungus is capable of producing human-relevant metabolites including the exact isomers. The capacity of the fungus C. elegans to allow for NMR structural characterisation by enabling production of large amounts of metabolites makes it an ideal model to complement metabolism studies.

  1. Templated Atom-Precise Galvanic Synthesis and Structure Elucidation of a [Ag 24 Au(SR) 18 ] − Nanocluster

    KAUST Repository

    Bootharaju, Megalamane Siddaramappa

    2015-11-27

    Synthesis of atom-precise alloy nanoclusters with uniform composition is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag24Au(SR)18]- cluster (SR: thiolate) using a pure [Ag25(SR)18]- cluster as a template. Conversely, the direct synthesis of Ag24Au cluster leads to a mixture of [Ag25-xAux(SR)18]-, x=1-8. Mass spectrometry and crystallography of [Ag24Au(SR)18]- reveal the presence of the Au heteroatom at the Ag25 center, forming Ag24Au. The successful exchange of the central Ag of Ag25 with Au causes perturbations in the Ag25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag25 and Ag24Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single-atom level.

  2. In situ analysis and structural elucidation of sainfoin (Onobrychis viciifolia) tannins for high-throughput germplasm screening.

    Science.gov (United States)

    Gea, An; Stringano, Elisabetta; Brown, Ron H; Mueller-Harvey, Irene

    2011-01-26

    A rapid thiolytic degradation and cleanup procedure was developed for analyzing tannins directly in chlorophyll-containing sainfoin ( Onobrychis viciifolia ) plants. The technique proved suitable for complex tannin mixtures containing catechin, epicatechin, gallocatechin, and epigallocatechin flavan-3-ol units. The reaction time was standardized at 60 min to minimize the loss of structural information as a result of epimerization and degradation of terminal flavan-3-ol units. The results were evaluated by separate analysis of extractable and unextractable tannins, which accounted for 63.6-113.7% of the in situ plant tannins. It is of note that 70% aqueous acetone extracted tannins with a lower mean degree of polymerization (mDP) than was found for tannins analyzed in situ. Extractable tannins had between 4 and 29 lower mDP values. The method was validated by comparing results from individual and mixed sample sets. The tannin composition of different sainfoin accessions covered a range of mDP values from 16 to 83, procyanidin/prodelphinidin (PC/PD) ratios from 19.2/80.8 to 45.6/54.4, and cis/trans ratios from 74.1/25.9 to 88.0/12.0. This is the first high-throughput screening method that is suitable for analyzing condensed tannin contents and structural composition directly in green plant tissue.

  3. Cryo-EM structures of the mammalian endo-lysosomal TRPML1 channel elucidate the combined regulation mechanism

    Directory of Open Access Journals (Sweden)

    Sensen Zhang

    2017-09-01

    Full Text Available Abstract TRPML1 channel is a non-selective group-2 transient receptor potential (TRP channel with Ca2+ permeability. Located mainly in late endosome and lysosome of all mammalian cell types, TRPML1 is indispensable in the processes of endocytosis, membrane trafficking, and lysosome biogenesis. Mutations of TRPML1 cause a severe lysosomal storage disorder called mucolipidosis type IV (MLIV. In the present study, we determined the cryo-electron microscopy (cryo-EM structures of Mus musculus TRPML1 (mTRPML1 in lipid nanodiscs and Amphipols. Two distinct states of mTRPML1 in Amphipols are added to the closed state, on which could represent two different confirmations upon activation and regulation. The polycystin-mucolipin domain (PMD may sense the luminal/extracellular stimuli and undergo a “move upward” motion during endocytosis, thus triggering the overall conformational change in TRPML1. Based on the structural comparisons, we propose TRPML1 is regulated by pH, Ca2+, and phosphoinositides in a combined manner so as to accommodate the dynamic endocytosis process.

  4. Structural elucidation and antioxidant activity of lignin isolated from rice straw and alkali‑oxygen black liquor.

    Science.gov (United States)

    Jiang, Bo; Zhang, Yu; Gu, Lihui; Wu, Wenjuan; Zhao, Huifang; Jin, Yongcan

    2018-05-17

    Alkali‑oxygen cooking of lignocellulose offers lignin many structural properties and bioactivities for biorefinery. In this work, milled wood lignin (MWL) and alkali‑oxygen lignin (AOL) were isolated from rice straw and alkali‑oxygen black liquor, respectively. The lignin structure was characterized by spectroscopy and wet chemistry. Antioxidant activity of lignins was assessed by DPPH·and ABTS scavenging ability assay. Results showed the oxidization and condensation of lignin occurred during alkali‑oxygen cooking. The p-hydroxyphenyl was more easily removed from rice straw than guaiacyl and syringyl units. The ester or ether linkages derived from hydroxycynnamic acids, and the main interunit linkages, i.e. β-O-4' bonds, were mostly cleaved. Lignin-xylan complex had high reactivity under alkali‑oxygen condition. Tricin, incorporated into lignin, was detected in MWL but was absent in AOL. Nitrobenzene oxidation showed MWL can well represent the protolignin of rice straw, and the products yield decreased dramatically after alkali‑oxygen cooking. AOL had higher radical scavenging ability than MWL indicating alkali‑oxygen cooking was an effective pathway for the enhancement of antioxidant activity of lignin. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Structure of restacked MoS{sub 2} and WS{sub 2} elucidated by electron crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Heising, J; Kanatzidis, M G

    1999-02-03

    There has been a lot of confusion about the nature of restacked MoS{sub 2} and WS{sub 2}. The structure has been proposed to be trigonal TiS{sub 2} type with octahedral M{sup 4} and called 1T-MoS{sub 2}. The presence of a distortion in the metal plane that gives rise to a superstructure has been suggested. Electron crystallographic studies on small (submicron) single crystal domains of restacked WS{sub 2} and MoS{sub 2} have been performed to solve their superstructure. It was shown that what initially seems to be a trigonal crystal is actually a triplet of three individual orthorhombic crystals. Using two-dimensional hk0 data from films for both triple and single crystals the authors calculated corresponding Patterson projections, which reveal a severe distortion in the Mo/W plane, forming infinite zigzag chains. The projection of the structure suggests M-M distances of 2.92 and 2.74 {angstrom} for MoS{sub 2} and Ws{sub 2}, respectively. Least-squares refinement from the single-crystal data gives R{sub 1} = 13.3% for WS{sub 2} and R{sub 1} = 15.3% for MoS{sub 2}. Therefore, it is proposed that restacked MoS{sub 2} and WS{sub 2} are not 1T form but rather WTe{sub 2} type.

  6. Elucidation of structural, vibrational and dielectric properties of transition metal (Co2+) doped spinel Mg-Zn chromites

    Science.gov (United States)

    Choudhary, Pankaj; Varshney, Dinesh

    2018-05-01

    Co2+ doped Mg-Zn spinel chromite compositions Mg0.5Zn0.5-xCoxCr2O4 (0.0 ≤ x ≤ 0.5) have been synthesized by the high-temperature solid state method. Synchrotron and X-ray diffraction (XRD) studies show single-phase crystalline nature. The structural analysis is validated by Rietveld refinement confirms the cubic structure with space group Fd3m. Crystallite size is estimated from Synchrotron XRD which was found to be 30-34 nm. Energy dispersive analysis confirms stoichiometric Mg0.5Zn0.5-xCoxCr2O4 composition. Average crystallite size distribution is estimated from imaging software (Image - J) of SEM is in the range of 100-250 nm. Raman spectroscopy reveals four active phonon modes, and a pronounced red shift is due to enhanced Co2+ concentration. Increased Co2+ concentration in Mg-Zn chromites shows a prominent narrowing of band gap from 3.46 to 2.97 eV. The dielectric response is attributed to the interfacial polarization, and the electrical modulus study supports non-Debye type of dielectric relaxation. Ohmic junctions (minimum potential drop) at electrode interface are active at lower levels of doping (x transformer applications at high frequencies.

  7. Antioxidant activity and electrochemical elucidation of the enigmatic redox behavior of curcumin and its structurally modified analogues

    International Nuclear Information System (INIS)

    Jha, Niki S.; Mishra, Satyendra; Jha, Shailendra K.; Surolia, Avadhesha

    2015-01-01

    Highlights: • Structural analogues of curcumin have been synthesized. • Confirmation of redox behaviour emanates from H- shift from central methylene group in curcumin. • Mechanism of curcumin oxidation has been proposed. • Correlation between redox behavior and antioxidant activity has been established. - Abstract: Here, we report studies on the antioxidant activity and redox behavior of curcumin and its structurally modified synthetic analogues. We have synthesized a number of analogues of curcumin which abrogate its keto-enol tautomerism or substitute the methylene group at the centre of its heptadione moiety implicated in the hydride transfer and studied their redox property. From cyclic voltammetric studies, it is demonstrated that H- atom transfer from CH 2 group at the center of the heptadione link also plays an important role in the antioxidant properties of curcumin along with that of its phenolic –OH group. In addition, we also show that the conversion of 1, 3- dicarbonyl moiety of curcumin to an isosteric heterocycle as in pyrazole curcumin, which decreases its rotational freedom, leads to an improvement of its redox properties as well as its antioxidant activity

  8. Local structure of alkalis in mixed-alkali borate glass to elucidate the origin of mixed-alkali effect

    Directory of Open Access Journals (Sweden)

    Yomei Tokuda

    2015-12-01

    Full Text Available We report the structural analysis of Na+ and Cs+ in sodium cesium borate crystals and glasses using 23Na and 133Cs magic-angle spinning nuclear magnetic resonance (MAS NMR spectroscopy. The composition dependence of NMR spectra of the borate was similar to that of the silicate: (1 the peak position of cesium borate crystals shifted to upfield for structures with larger Cs+ coordination numbers, (2 the MAS NMR spectra of xNa2O-yCs2O-3B2O3 (x = 0, 0.25, 0.5, 0.75, 1.0, x + y = 1 glass showed that the average coordination number (CN of both the alkali cations decreases with increasing Cs+/(Na+ + Cs+ ratio. However, the degree of decrement in borates is much smaller than that in silicates. We have considered that the small difference in CN is due to 4-coordinated B, because it is electrically compensated by the alkali metal ions resulting in the restriction of having various coordinations of O to alkali metal.

  9. On the use of atomistic simulations to aid bulk metallic glasses structural elucidation with solid-state NMR.

    Science.gov (United States)

    Ferreira, Ary R; Rino, José P

    2017-08-24

    Solid-state nuclear magnetic resonance (ssNMR) experimental 27 Al metallic shifts reported in the literature for bulk metallic glasses (BMGs) were revisited in the light of state-of-the-art atomistic simulations. In a consistent way, the Gauge-Including Projector Augmented-Wave (GIPAW) method was applied in conjunction with classical molecular dynamics (CMD). A series of Zr-Cu-Al alloys with low Al concentrations were selected as case study systems, for which realistic CMD derived structural models were used for a short- and medium-range order mining. That initial procedure allowed the detection of trends describing changes on the microstructure of the material upon Al alloying, which in turn were used to guide GIPAW calculations with a set of abstract systems in the context of ssNMR. With essential precision and accuracy, the ab initio simulations also yielded valuable trends from the electronic structure point of view, which enabled an overview of the bonding nature of Al-centered clusters as well as its influence on the experimental ssNMR outcomes. The approach described in this work might promote the use of ssNMR spectroscopy in research on glassy metals. Moreover, the results presented demonstrate the possibility to expand the applications of this technique, with deeper insight into nuclear interactions and less speculative assignments.

  10. Phytochemical study of the trunk bark of Citharexylum spinosum L. growing in Tunisia: Isolation and structure elucidation of iridoid glycosides.

    Science.gov (United States)

    Saidi, Ilyes; Waffo-Téguo, Pierre; Ayeb-Zakhama, Asma E L; Harzallah-Skhiri, Fethia; Marchal, Axel; Ben Jannet, Hichem

    2018-02-01

    A phytochemical investigation of the trunk bark ethyl acetate extract of Citharexylum spinosum L. has led to the isolation of four previously undescribed iridoid glycosides, tunispinosides A-D, and five known phenylethanoid glycosides, verbascoside, leucosceptoside A, martynoside, isoverbascoside and plantainoside C, together with 4-hydroxy-2,6-dimethoxyphenyl 6'-O-vanilloyl-β-D-glucopyranoside, two 8,3'-neolignan glycosides, plucheosides D 1 -D 2 , coniferyl aldehyde, vanillic acid, syringic acid, ferulic acid and tyrosol. All compounds were isolated for the first time from C. spinosum. Their isolation was carried out using silica gel column and high performance liquid chromatography (HPLC). Structures were established by spectroscopic means including 1D and 2D NMR experiments, and spectrometric ESI-HRMS analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Structural elucidation of in vitro and in vivo metabolites of emodin in rats by LC -ESI-MS/MS

    International Nuclear Information System (INIS)

    Wang, D.; Zhu, Q.; Chen, G.; Liu, B.; Chen, L.

    2013-01-01

    Emodin is a widely occurring natural product and has been studied extensively for its varieties of pharmacological activity. In attempt to know more deeply about its metabolism, this paper investigated the metabolites of emodin in rats, including its in vitro conversion product by intestinal microflora and urinary metabolites. The detection of emodin metabolites was performed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) with negative ion mode. By comparing the changes of metabolites in molecular masses (delta M), product ions and retention times with those of the parent drug, six metabolites (8-O-methylemodin, omega-hydroxyemodin, x-hydroxyemodin, emodin glucuronide, hydroxyemodin glucuronide and emodin sulfate) were observed,and what is more, the metabolite hydroxyemodin glucuronide was first reported in this article. For some metabolites, identification of their precise structure needs to be confirmed by other techniques such as the 1H and 13C NMR. (author)

  12. 3-Ishwarone, a Rare Ishwarane Sesquiterpene from Peperomia scandens Ruiz & Pavon: Structural Elucidation through a Joint Experimental and Theoretical Study

    Directory of Open Access Journals (Sweden)

    Fernando M. dos S.

    2013-10-01

    Full Text Available 3-Ishwarone, (1, a sesquiterpene with a rare ishwarane skeleton, was isolated from Peperomia scandens Ruiz & Pavon (Piperaceae. Its structure was unambiguously determined by 1D- and 2D-NMR and infrared analyses, as well as by comparative theoretical studies which involved calculations of 13C-NMR chemical shifts, using the Density Functional Theory (DFT with the mPW1PW91 hybrid functional and Pople’s 6-31G(d basis set, and of vibrational frequencies, using the B3LYP hybrid functional and triple ζ Dunning’s correlation consistent basis set (cc-pVTZ, of (1 and three of its possible diastereomers, compounds 2–4.

  13. Development of a sensitive method for a structural elucidation of acyl carnitines by means of GC-MS techniques

    International Nuclear Information System (INIS)

    Altmann, E.

    1999-11-01

    The goal of the present work was to develop a sensitive and reliable method to characterize the urinary acyl carnitines, to further establish it as routine procedure in hospitals, especially in Pedriatic Departments. The determination of the excreted acyl carnitines allows drawing conclusions on errors or deviations in the cellular metabolism. Applying the volatile lactone derivatives of the acyl carnitines various methods of GC/MS technique are compared. With the examined lactones under concern EI mass spectra furnish just a first incomplete information. Frequently the molecular peaks are not sufficiently intense. Yet by means of the retention times, the signals m/z 84, 85 and 144 as ion traces, as well as the characteristic fragmentation helpful information is provided. Concerning the +CI/NH 3 - mass spectra the protonated molecular ions (M + H) + and the usually very intense (M + NH 4 ) + - ions unambiguously render structural assignments. In the case of the - CI/NH 3 - mass spectra the (M-1) and (M-85) ions allow definitive assignments due to their lesser fragmentation tendency. Each of the analytical outcoming can be regarded as leading contribution in helpfully establishing the current method in every clinical hospital. (author)

  14. Isolation, structure elucidation and antibacterial activity of methyl-4,8-dimethylundecanate from the marine actinobacterium Streptomyces albogriseolus ECR64.

    Science.gov (United States)

    Thirumurugan, Durairaj; Vijayakumar, Ramasamy; Vadivalagan, Chithravel; Karthika, Pushparaj; Alam Khan, Md Khurshid

    2018-05-25

    Around 120 actinobacterial colonies were isolated from various regions of marine East coast region of Tamil Nadu, India. Among them, 33 were morphologically distinct and they were preliminarily screened for their antibacterial activity against Pseudomonas fluorescens, Vibrio cholerae, V. parahaemolyticus, V. alginolyticus, and Aeromonas hydrophila by cross-streak plate technique. Among the isolated, the isolate ECR64 exhibited maximum zone of inhibition against fish pathogenic bacteria. The crude bioactive compounds were extracted from the isolate ECR64 using different organic solvents which exhibited maximum antibacterial activity. Separation and purification of the bioactive compounds were made by column chromatography which yielded 27 fractions and were re-chromatographed to obtain the active compound. Ultra violet (UV), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectral studies were used to predict the structure of the active compound which was identified as methyl-4,8-dimethylundecanate. The potential isolate ECR64 was identified as Streptomyces albogriseolus by phylogenetic, phenotypic and genotypic (16S rRNA gene sequence) analyses. The identified compound methyl-4,8-dimethylundecanate can be used as potential and alternative drug in disease management of aquaculture. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Application of the independent molecule model to elucidate the dynamics of structure I methane hydrate: a third report.

    Science.gov (United States)

    Yoshioki, Shuzo

    2009-01-01

    Two new model systems of methane hydrate, larger than the previous systems, are constructed. One consists of 63 small and large cages with a small cage at the centre. The other has 65 small and large cages with a large cage at the centre. Three different H-bonding network patterns between water are formed, and three random orientations of methane in each cage are chosen. Using the surface water fixed method, we obtained the energy minimum conformations, fitted to the X-ray crystallographic structure. With normal mode analysis, we calculated frequencies of 2915.1 cm(-1) for a small cage, and 2911.0 cm(-1) for a large cage. These frequencies are a little nearer to the Raman spectra than were previous model systems. Treating three force constants of anharmonic potential energy and the strength of H-bonding between methane and water as four parameters, we obtained frequencies of 2913.6 cm(-1) for a small cage, a little lower than the Raman, and 2906.6 cm(-1) for a large cage, a little higher than the Raman. The calculations thus almost reach the Raman spectra.

  16. Elucidating the role of surface passivating ligand structural parameters in hole wave function delocalization in semiconductor cluster molecules.

    Science.gov (United States)

    Teunis, Meghan B; Nagaraju, Mulpuri; Dutta, Poulami; Pu, Jingzhi; Muhoberac, Barry B; Sardar, Rajesh; Agarwal, Mangilal

    2017-09-28

    This article describes the mechanisms underlying electronic interactions between surface passivating ligands and (CdSe) 34 semiconductor cluster molecules (SCMs) that facilitate band-gap engineering through the delocalization of hole wave functions without altering their inorganic core. We show here both experimentally and through density functional theory calculations that the expansion of the hole wave function beyond the SCM boundary into the ligand monolayer depends not only on the pre-binding energetic alignment of interfacial orbitals between the SCM and surface passivating ligands but is also strongly influenced by definable ligand structural parameters such as the extent of their π-conjugation [π-delocalization energy; pyrene (Py), anthracene (Anth), naphthalene (Naph), and phenyl (Ph)], binding mode [dithiocarbamate (DTC, -NH-CS 2 - ), carboxylate (-COO - ), and amine (-NH 2 )], and binding head group [-SH, -SeH, and -TeH]. We observe an unprecedentedly large ∼650 meV red-shift in the lowest energy optical absorption band of (CdSe) 34 SCMs upon passivating their surface with Py-DTC ligands and the trend is found to be Ph- wave function delocalization rather than carrier trapping and/or phonon-mediated relaxation. Taken together, knowledge of how ligands electronically interact with the SCM surface is crucial to semiconductor nanomaterial research in general because it allows the tuning of electronic properties of nanomaterials for better charge separation and enhanced charge transfer, which in turn will increase optoelectronic device and photocatalytic efficiencies.

  17. Structural elucidation and magnetic behavior evaluation of Cu-Cr doped BaCo-X hexagonal ferrites

    Science.gov (United States)

    Azhar Khan, Muhammad; Hussain, Farhat; Rashid, Muhammad; Mahmood, Asif; Ramay, Shahid M.; Majeed, Abdul

    2018-04-01

    Ba2-xCuxCo2CryFe28-yO46 (x = 0.0, 0.1, 0.2, 0.3, 0.4, y = 0.0, 0.2, 0.4, 0.6, 0.8) X-type hexagonal ferrites were synthesized via micro-emulsion route. The techniques which were applied to characterize the prepared samples are as follows: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Dielectric measurements and vibrating sample magnetometer (VSM). The structural parameters i.e. lattice constant (a, c), cell volume (V), X-ray density, bulk density and crystallite size of all the prepared samples were obtained using XRD analysis. The lattice parameters 'a' and 'c' increase from 5.875 Å to 5.934 Å and 83.367 Å to 83.990 Å respectively. The crystallite size of investigated samples lies in the range of 28-32 nm. The magnetic properties of all samples have been calculated by vibrating sample magnetometer (VSM) analysis. The increase in coercivity (Hc) was observed with the increase of doping contents. It was observed that the coercivity (Hc) of all prepared samples is inversely related to the crystalline size which reflects that all materials are super-paramagnetic. The dielectric parameters i.e. dielectric constant, dielectric loss, tangent loss etc were obtained in the frequency range of 1 MHz-3 GHz and followed the Maxwell-Wagner's model. The significant variation the dielectric parameters are observed with increasing frequency. The maximum Q value is obtained at ∼2 GHz due to which these materials are used for high frequency multilayer chip inductors.

  18. On the use of X-ray absorption spectroscopy to elucidate the structure of lutetium adenosine mono- and triphosphate complexes.

    Science.gov (United States)

    Mostapha, S; Berthon, C; Fontaine-Vive, F; Gaysinski, M; Guérin, L; Guillaumont, D; Massi, L; Monfardini, I; Solari, P L; Thomas, O P; Charbonnel, M C; Den Auwer, C

    2014-02-01

    chemical calculations has been implemented in order to assess the lutetium coordination arrangement for the two nucleotides. In all the complexes described in the article, the lutetium cation is coordinated by the phosphate groups of the nucleotide plus additional putative water molecules with various tridimensional arrangements. With AMP 1:2 and ATP 1:1 solid-state compounds, polynuclear complexes are assumed to be obtained. In contrast, with ATP 1:2 soluble compound, the Lu coordination sphere is saturated by two ATP ligands, and this favors the formation of a mononuclear complex. In order to further interpret the EXAFS data obtained at the Lu LIII edge, model structures have been calculated for the 1:1 and 1:2 ATP complexes. They are discussed and compared to the EXAFS best fit metrical parameters.

  19. Isolation, structural elucidation, MS profiling, and evaluation of triglyceride accumulation inhibitory effects of benzophenone C-glucosides from leaves of Mangifera indica L.

    Science.gov (United States)

    Zhang, Yi; Han, Lifeng; Ge, Dandan; Liu, Xuefeng; Liu, Erwei; Wu, Chunhua; Gao, Xiumei; Wang, Tao

    2013-02-27

    Seventy percent ethanol-water extract from the leaves of Mangifera indica L. (Anacardiaceae) was found to show an inhibitory effect on triglyceride (TG) accumulation in 3T3-L1 cells. From the active fraction, six new benzophenone C-glucosides, foliamangiferosides A(3) (1), A(4) (2), C(4) (3), C(5) (4), C(6) (5), and C(7) (6) together with 11 known benzophenone C-glucosides (7-17) were obtained. In this paper, isolation, structure elucidation (1-6), and MS fragment cleavage pathways of all 17 isolates were studied. 1-6 showed inhibitory effects on TG and free fatty acid accumulation in 3T3-L1 cells at 10 μM.

  20. Electrochemical Synthesis, Structure Elucidation and Antibacterial Evaluation of 9a-aza-9a-chloro-9a-homoerythromycin A

    Directory of Open Access Journals (Sweden)

    Zoran Mandic

    2014-09-01

    Full Text Available Electrochemical synthesis, structure elucidation and antibacterial evaluation of 9a-aza-9a-chloro-9a-homoerythromycin A were carried out. It was found that the anodic oxidation of 9a-aza-9a-homoerythromycin A via electrogenerated reactive chlorine species leads to the chlorination of lactam nitrogen in high yield provided the pH of the reaction mixture is maintained above 3. NOESY spectra reveal the existence of the mixture of two conformational families in the solution, the "folding-out" conformer being slightly more abundant comparing to 9a-Aza-9a-homoerythromycin A. The chlorine substitution of lactam hydrogen resulted in improved antimicrobial potency against Sreptococcus pyogenes PSCB0542, Moraxella catarrhalis ATCC 25238, Haemophilus  influenzae ATCC 49247 and Enteroccocus faecalis ATCC 29212.

  1. 3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations

    Science.gov (United States)

    Page, Alister J.; Elbourne, Aaron; Stefanovic, Ryan; Addicoat, Matthew A.; Warr, Gregory G.; Voïtchovsky, Kislon; Atkin, Rob

    2014-06-01

    In situ amplitude modulated atomic force microscopy (AM-AFM) and quantum chemical simulations are used to resolve the structure of the highly ordered pyrolytic graphite (HOPG)-bulk propylammonium nitrate (PAN) interface with resolution comparable with that achieved for frozen ionic liquid (IL) monolayers using STM. This is the first time that (a) molecular resolution images of bulk IL-solid interfaces have been achieved, (b) the lateral structure of the IL graphite interface has been imaged for any IL, (c) AM-AFM has elucidated molecular level structure immersed in a viscous liquid and (d) it has been demonstrated that the IL structure at solid surfaces is a consequence of both thermodynamic and kinetic effects. The lateral structure of the PAN-graphite interface is highly ordered and consists of remarkably well-defined domains of a rhomboidal superstructure composed of propylammonium cations preferentially aligned along two of the three directions in the underlying graphite lattice. The nanostructure is primarily determined by the cation. Van der Waals interactions between the propylammonium chains and the surface mean that the cation is enriched in the surface layer, and is much less mobile than the anion. The presence of a heterogeneous lateral structure at an ionic liquid-solid interface has wide ranging ramifications for ionic liquid applications, including lubrication, capacitive charge storage and electrodeposition.In situ amplitude modulated atomic force microscopy (AM-AFM) and quantum chemical simulations are used to resolve the structure of the highly ordered pyrolytic graphite (HOPG)-bulk propylammonium nitrate (PAN) interface with resolution comparable with that achieved for frozen ionic liquid (IL) monolayers using STM. This is the first time that (a) molecular resolution images of bulk IL-solid interfaces have been achieved, (b) the lateral structure of the IL graphite interface has been imaged for any IL, (c) AM-AFM has elucidated molecular level

  2. Heparin sodium compliance to the new proposed USP monograph: elucidation of a minor structural modification responsible for a process dependent 2.10 ppm NMR signal.

    Science.gov (United States)

    Mourier, Pierre A J; Guichard, Olivier Y; Herman, Fréderic; Viskov, Christian

    2011-01-25

    Heparin is a highly sulfated hetero polysaccharide mixture found and extracted from mammalian tissues. It has been widely used as an anticoagulant drug during the past decades. In the new proposed USP heparin monograph, the ¹H NMR acceptance criteria to prevent contamination by over sulfated chondroitin sulfate (OSCS), or other persulfated glycosaminoglycans, specifies that no unidentified signals greater than 4% of the mean of signal height of 1 and 2 should be present in the following ranges: 0.10-2.00, 2.10-3.20, and 5.70-8.00 ppm. However, those criteria do not take into account the impact of potential structural modifications generated by the heparin manufacturing processes. In fact, starting from pig mucosa, heparin purification involves oxidizing reagents such as sodium peroxide, potassium permanganate and peracetic acid. In the present work, we demonstrate that potassium permanganate treated heparins show a small but characteristic extra signal at 2.10 ppm. Controlled heparinase I depolymerisation is used to target and excise the oligosaccharide responsible for this extra signal from the polysaccharide backbone. By using orthogonal chromatographic techniques, the fingerprint oligosaccharide was isolated and its structure elucidated. Without the identification of this structural moiety, such purified heparins may have been considered as non-compliant drug substance and not suitable for pharmaceutical use. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Computer-assisted structure elucidation from 13C-NMR-Spectra. I. The development of a three-dimensional structure code. II. The development of an isomer generating program

    International Nuclear Information System (INIS)

    Schuetz, V.

    1999-05-01

    The presented thesis consists of two separate programs which both aid the automated structure elucidation in the CSEARCH database system. A successful utilization of a large collection of NMR reference spectra for the prediction of chemical shift values is dependent on a strong correlation between the spectral data and the structural information via unique coding. By now, this was done using the two-dimensional HOSE code, which turned out to be insufficient whenever stereochemical effects other than cis/trans-isomerism contribute to the chemical shift values. Therefore, this new algorithm has been developed to derive the demanded three-dimensional descriptors. The calculation is performed by matching the query structures against pattern molecules taken from a carefully selected library of ring skeletons. No three-dimensional coordinates are necessary, since the algorithm elucidates the descriptors on base of two-dimensional structures having their stereocenters specified using 'up/down' bonds. The descriptors are defined as number of interactions over 3 to 5 bonds, number of cis-substituents over 1 to 2 ringbonds and markers for axial substituents. This approach of deriving descriptors for steric interactions has successfully extended the HOSE coding scheme and has been implemented into a neural network; both methods allow for high-quality prediction of 13 C-NMR chemical shift values. The second algorithm is an isomer generating program named GENERAL, which efficiently supports the structure elucidation process by calculating all mathematically possible structures to a given molecular formula. The resulting list of structures is exhaustive and free of redundancy. Besides the basic input information - like the molecular formula and the specification of structural fragments, constraints can be defined to restrict the number of resulting structures. The most valuable information is provided by state-of-the-art 2D-NMR experiments and can be easily incorporated into

  4. Pituitary response to thyrotropin releasing hormone in children with overweight and obesity.

    Science.gov (United States)

    Rijks, Jesse; Penders, Bas; Dorenbos, Elke; Straetemans, Saartje; Gerver, Willem-Jan; Vreugdenhil, Anita

    2016-08-03

    Thyroid stimulating hormone (TSH) concentrations in the high normal range are common in children with overweight and obesity, and associated with increased cardiovascular disease risk. Prior studies aiming at unravelling the mechanisms underlying these high TSH concentrations mainly focused on factors promoting thyrotropin releasing hormone (TRH) production as a cause for high TSH concentrations. However, it is unknown whether TSH release of the pituitary in response to TRH is affected in children with overweight and obesity. Here we describe TSH release of the pituitary in response to exogenous TRH in 73 euthyroid children (39% males) with overweight or (morbid) obesity. Baseline TSH concentrations (0.9-5.5 mU/L) were not associated with BMI z score, whereas these concentrations were positively associated with TSH concentrations 20 minutes after TRH administration (r(2) = 0.484, p obesity. The clinical significance and the intermediate factors contributing to pituitary TSH release need to be elucidated in future studies.

  5. Structural elucidation of novel bioactive compound (2-chloro-1-(2-chlorocyclopropyl-2-(4-nitrophenylethanone from basidiomycetous fungus Lentinus squarrosulus

    Directory of Open Access Journals (Sweden)

    Usha N.

    2016-02-01

    Full Text Available While screening for bioactive compounds from macrofungi of Western Ghats of Karnataka, Lentinus squarrosulus a member of polyporaceae was collected and mycelium of the fungus was obtained on potato dextrose agar medium and cultured in a liquid medium (containing 2% glucose, 1% peptone and 2% yeast extract for 20 days on a rotary shaker for the production of secondary metabolites. The cell free culture fluid (100ml was subjected to solvent extraction with dichloromethane (100ml and the extract was evaluated for antimicrobial activity by agar diffusion method and cytotoxic activity of the extract was also determined by MTT and SRB assay on MCF7 cell line. The results revealed that the dichloromethane extract was inhibitory against Escherichia coli, Enterobacter aerogenes, Staphylococcus aureus and Bacillus subtilus and also fungi such as Aspergillus niger, Fusarium solani and Trichoderma harzianum. The extract showed 13-27% cell inhibition at 63-1000 µg/ml concentration by MTT and SRB assays on MCF7 cell line. The structural elucidation of the compound by spectroscopic NMR (1H and C13, IR and mass spectrometric analysis confirmed the presence of 2-chloro-1-(2-chlorocyclopropyl-2-(4-nitrophenylethanone responsible for antimicrobial and cytotoxic activity.

  6. Structural elucidation of a water-insoluble glucan produced by a glucosyltransferase of Streptococcus mutans 6715 by chemical and instrumental analysis

    International Nuclear Information System (INIS)

    Davis, H.M.

    1985-01-01

    The structure of a water-insoluble polysaccharide produced by the glucosyltransferase of Streptococcus mutans 6715 has been elucidated through the use of periodate oxidation, Smith degradation, dextranase digestion, concanavalin A binding studies, methylation followed by methanolysis, reductive cleavage and gas chromatographic-mass spectroscopic analysis, carbon-13 nuclear magnetic resonance and fast atom bombardment mass spectroscopy. These studies show that the water-insoluble glucan is comprised of 67% α-(1-3) linkages in a contiguous backbone with the remaining 33% existing as α-(1-6) linkages possibly as linear residues extending from α-(1-6) branch points. 14% of the residues exist as branch points and the ratio of linear extending α-(1-3) residues in the backbone to linear extending α-(1-6) residues in the side chain was found to be 5:2. Dextranase digestion and Smith degradation both gave rise to a high molecular weight fraction which is only α-(1-3) linked. In addition, the average length of the side chains was shown to not exceed 3 residues

  7. Identification of the chemical constituents of Chinese medicine Yi-Xin-Shu capsule by molecular feature orientated precursor ion selection and tandem mass spectrometry structure elucidation.

    Science.gov (United States)

    Wang, Hong-ping; Chen, Chang; Liu, Yan; Yang, Hong-Jun; Wu, Hong-Wei; Xiao, Hong-Bin

    2015-11-01

    The incomplete identification of the chemical components of traditional Chinese medicinal formula has been one of the bottlenecks in the modernization of traditional Chinese medicine. Tandem mass spectrometry has been widely used for the identification of chemical substances. Current automatic tandem mass spectrometry acquisition, where precursor ions were selected according to their signal intensity, encounters a drawback in chemical substances identification when samples contain many overlapping signals. Compounds in minor or trace amounts could not be identified because most tandem mass spectrometry information was lost. Herein, a molecular feature orientated precursor ion selection and tandem mass spectrometry structure elucidation method for complex Chinese medicine chemical constituent analysis was developed. The precursor ions were selected according to their two-dimensional characteristics of retention times and mass-to-charge ratio ranges from herbal compounds, so that all precursor ions from herbal compounds were included and more minor chemical constituents in Chinese medicine were identified. Compared to the conventional automatic tandem mass spectrometry setups, the approach is novel and can overcome the drawback for chemical substances identification. As an example, 276 compounds from the Chinese Medicine of Yi-Xin-Shu capsule were identified. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Anti- and Pro-Lipase Activity of Selected Medicinal, Herbal and Aquatic Plants, and Structure Elucidation of an Anti-Lipase Compound

    Directory of Open Access Journals (Sweden)

    Muhammad Abubakar Ado

    2013-11-01

    Full Text Available Plants that help in slowing down the digestion of triacylglycerols (TAGs in the pancreas and small intestine of humans play an important role in the reduction of obesity. On the other hand, there may be plants or plant parts that stimulate intestinal lipolytic activity, thus contributing to greater TAG assimilation. The aim of this study was to evaluate the aqueous methanolic extracts of ninety eight (98 medicinal, herbal and aquatic plant materials from Malaysia for their effect on porcine pancreatic lipase (PPL activity and to identify the structure of an anti-lipase compound from one of the sources. The degree of inhibition was also quantified as relative to orlistat activity against PPL (orlistat equivalents. Results revealed that while 19.4% of the extracts were found to have anti-lipase activity ≥80%, 12% were actually found to promote PPL activity. Twenty two percent (22.4% exhibited moderate inhibition (41%–80% and 2% were neutral toward PPL activity. The ripe fruit of Averrhoa carambola and the leaves of Archidendron jiringa (Jack I.C Nielsen L. (jering, Cynometra cauliflora (nam-nam and Aleurites moluccana (L. Willd (candle nut/buah keras had the highest (100% anti-lipase activity and are equivalent to 0.11 µg orlistat/mL. Plants that stimulated lipase activity included Pimpinella anisum L. (aniseed/jintan manis, activating the enzyme by 186.5%. Kaempferol 3-O-rhamnoside was isolated from the ethyl acetate fraction of C. cauliflora leaves and found to be an active lipase inhibitor. The structure was elucidated using 1H-NMR, 13C-NMR and 2D-NMR analyses.

  9. Anti- and pro-lipase activity of selected medicinal, herbal and aquatic plants, and structure elucidation of an anti-lipase compound.

    Science.gov (United States)

    Ado, Muhammad Abubakar; Abas, Faridah; Mohammed, Abdulkarim Sabo; Ghazali, Hasanah M

    2013-11-26

    Plants that help in slowing down the digestion of triacylglycerols (TAGs) in the pancreas and small intestine of humans play an important role in the reduction of obesity. On the other hand, there may be plants or plant parts that stimulate intestinal lipolytic activity, thus contributing to greater TAG assimilation. The aim of this study was to evaluate the aqueous methanolic extracts of ninety eight (98) medicinal, herbal and aquatic plant materials from Malaysia for their effect on porcine pancreatic lipase (PPL) activity and to identify the structure of an anti-lipase compound from one of the sources. The degree of inhibition was also quantified as relative to orlistat activity against PPL (orlistat equivalents). Results revealed that while 19.4% of the extracts were found to have anti-lipase activity ≥80%, 12% were actually found to promote PPL activity. Twenty two percent (22.4%) exhibited moderate inhibition (41%-80%) and 2% were neutral toward PPL activity. The ripe fruit of Averrhoa carambola and the leaves of Archidendron jiringa (Jack) I.C Nielsen L. (jering), Cynometra cauliflora (nam-nam) and Aleurites moluccana (L.) Willd (candle nut/buah keras) had the highest (100%) anti-lipase activity and are equivalent to 0.11 µg orlistat/mL. Plants that stimulated lipase activity included Pimpinella anisum L. (aniseed/jintan manis), activating the enzyme by 186.5%. Kaempferol 3-O-rhamnoside was isolated from the ethyl acetate fraction of C. cauliflora leaves and found to be an active lipase inhibitor. The structure was elucidated using 1H-NMR, 13C-NMR and 2D-NMR analyses.

  10. Application of high-field n.m.r. spectroscopy to the structural elucidation of natural products. The structure of rubellin, a noval bufadienolide glycoside from Urginea rubella

    International Nuclear Information System (INIS)

    Steyn, P.S.; Van Heerden, F.R.; Vleggaar, R.

    1986-01-01

    The structure and absolute configuration of rubellin, the major toxic principle of Urginea rubella, was determined by application of high-field 1 H n.m.r. spectroscopy. Rubellin proved to be a bufadienolide glycoside with the carbohydrate moiety doubly linked to the aglycone at the 2α- and 3β- positions

  11. Thyrotropin-luteinizing hormone/chorionic gonadotropin receptor extracellular domain chimeras as probes for thyrotropin receptor function

    International Nuclear Information System (INIS)

    Nagayama, Yuji; Wadsworth, H.L.; Chazenbalk, G.D.; Russo, D.; Seto, Pui; Rapoport, B.

    1991-01-01

    To define the sites in the extracellular domain of the human thyrotropin (TSH) receptor that are involved in TSH binding and signal transduction the authors constructed chimeric thyrotropin-luteinizing hormone/chorionic gonadotropin (TSH-LH/CG) receptors. The extracellular domain of the human TSH receptor was divided into five regions that were replaced, either singly or in various combinations, with homologous regions of the rat LH/CG receptor. The chimeric receptors were stably expressed in Chinese hamster ovary cells. The data obtained suggest that the carboxyl region of the extracellular domain (amino acid residues 261-418) and particularly the middle region (residues 171-260) play a role in signal transduction. The possibility is also raised of an interaction between the amino and carboxyl regions of the extracellular domain in the process of signal transduction. In summary, these studies suggest that the middle region and carboxyl half of the extracellular domain of the TSH receptor are involved in signal transduction and that the TSH-binding region is likely to span the entire extracellular domain, with multiple discontinuous contact sites

  12. Sex-Specific Associations Between Thyrotropin and Serum Lipid Profiles

    DEFF Research Database (Denmark)

    Meisinger, Christa; Ittermann, Till; Tiller, Daniel

    2014-01-01

    BACKGROUND: Population-based studies investigating the sex-specific association between thyrotropin (TSH) levels and serum lipid concentrations are scarce. We examined the association between TSH and total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL......) cholesterol, and triglycerides in men and women from the general population. Furthermore, the association with TSH outside and within the reference range and lipid levels was studied. METHODS: Individual data of 13,571 men and women without lipid medication of four population-based studies conducted...... in Western European adults were pooled for cross-sectional analyses. The association between TSH levels and lipid concentrations were analyzed by calculating sex-specific multivariable median regression models. RESULTS: In the pooled population, serum TSH levels were significantly positively associated...

  13. Thyrotropin-producing adenoma. Report of two clinical cases

    Directory of Open Access Journals (Sweden)

    Ani R. Karapetyan

    2017-03-01

    Full Text Available Diagnosis of hyperthyroidism does not present serious difficulties currently. Distribution of imaging techniques increasing the detection of pituitary adenomas every year. Thyrotropin-producing adenoma is a rare cause of hyperthyroidism. Early detection will alert its errors in treatment strategy, unjustified surgery on the thyroid gland, and will improve the quality of patients life. The article presents two clinical cases of thyroid-stimulating hormone (TSH-secreting pituitary adenomas in patients with different disease duration, and thus the presence of hyperthyroidism complications. Both patients were operated in the Federal Center of Neurosurgery Novosibirsk by transnasal transsphenoidal approach. The resistant euthyroidism was reached postoperatively, but in patients with long-term history of the disease, large size of adenoma in the postoperative period developed secondary adrenal insufficiency and her quality of life is significantly lower, taking into account comorbidities. The period of follow-up consists 3 years and one year respectively.

  14. Effect of Thyrotropin Suppression Therapy on Bone in Thyroid Cancer Patients

    OpenAIRE

    Papaleontiou, Maria; Hawley, Sarah T.; Haymart, Megan R.

    2015-01-01

    Background. The thyroid cancer incidence is rising. Despite current guidelines, controversy exists regarding the degree and duration of thyrotropin suppression therapy. Also, its potential skeletal effects remain a concern to physicians caring for thyroid cancer patients. We conducted a review of published data to evaluate existing studies focusing on the skeletal effects of thyrotropin suppression therapy in thyroid cancer patients. Materials and Methods. A systematic search of the PubMed, O...

  15. Comparison of pituitary and recombinant human thyrotropin standards in an immunoradiometric system

    International Nuclear Information System (INIS)

    Blanca Fernandez, Silvia; Rodriguez Gonzalez, Julio Cesar; Nisembaum Alas, Amaparo; Sevy Gonzalez, O.

    1998-01-01

    Results of two standards of human thyrotropin of pituitaries (B) and recombinant (C) origen supplied by the Instituto of pesquisas Energeticas y Nucleares, Brazil, were compared in our immunoradiometric reference system that use an human thyrotropin pituitary standard of local production (A). This work was supported by the International Atomic Energy Agency for an inter-regional comparison and set up of a reference standard

  16. Pharmacology of bovine and human thyrotropin: an historical perspective.

    Science.gov (United States)

    Robbins, J

    1999-05-01

    Before the induction of a brief period of hypothyroidism became the standard method for inducing 131I uptake in thyroid cancer diagnosis and therapy, several other methods were explored and used. At the dawn of this new era of recombinant human thyrotropin (TSH) it is of interest to reflect briefly on some of this work. Partially purified bovine TSH (bTSH) was supplied for many years by the Armour Company as Thytropar for intramuscular injection and was first used in thyroid cancer 50 years ago at the Montefiore Hospital and at the Memorial Sloan Kettering Cancer Center in New York City. Most of the patients were already hypothyroid and bTSH induced further 131I uptake in only a few. Experience over the next 30 years revealed frequent allergic reactions, occasionally serious ones, and in 1961 it was shown that prolonged use could result in resistance to both bTSH and human TSH. bTSH was, therefore, reserved for thyroid cancer patients unable to increase endogenous TSH when hypothyroid. bTSH also was used widely as a test to distinguish between hypothyroidism caused by thyroid or pituitary failure until it was replaced by thyrotropin-releasing hormone (TRH). In a few studies, TRH was also tested as an adjuvant to increase endogenous TSH and thus help to stimulate function in thyroid cancer, but this attracted little interest. Prolonged hypothyroidism, enhanced by antithyroid drugs, was used early on, but this very effective stimulant of thyroid cancer function was, for multiple reasons, discarded. Beginning interest 15 to 25 years ago in obtaining TSH from human pituitary glands, a byproduct of growth hormone production, was interrupted when this product was found to risk development of Creutzfeld-Jakob disease. Recombinant human TSH, a safe and effective substitute, is now ready for widespread use and development in thyroid cancer management.

  17. Structure elucidation of the diagnostic product ion at m/z 97 derived from androst-4-en-3-one-based steroids by ESI-CID and IRMPD spectroscopy

    NARCIS (Netherlands)

    Thevis, M.; Beuck, S.; Hoeppner, S.; Thomas, A.; Held, J.; Schaefer, M.; Oomens, J.; Schaenzer, W.

    2012-01-01

    Structure elucidation of steroids by mass spectrometry has been of great importance to various analytical arenas and numerous studies were conducted to provide evidence for the composition and origin of (tandem) mass spectrometry-derived product ions used to characterize and identify steroidal

  18. Changes in the sialylation and sulfation of secreted thyrotropin in congenital hypothyroidism

    International Nuclear Information System (INIS)

    Gyves, P.W.; Gesundheit, N.; Thotakura, N.R.; Stannard, B.S.; DeCherney, G.S.; Weintraub, B.D.

    1990-01-01

    The authors have examined the oligosaccharide structure of secreted thyrotropin (TSH) in perinatal and mature rats with congenital primary hypothyroidism. Rat pituitaries from euthyroid control animals and those rendered hypothyroid by methimazole treatment were incubated with [ 3 H]glucosamine in vitro. Secreted TSH was purified, and oligosaccharides were enzymatically released and characterized by anion-exchange HPLC. In perinatal hypothyroid animals compared with control animals, oligosaccharides from TSH α and β subunits contained more species with three or more negative charges. Moreover, perinatal hypothyroid animals demonstrated a dramatic increase in the ratio of sialylated to sulfated species within oligosaccharides of the same negative charge. In mature hypothyroid 9-week-old animals compared with control animals, changes were less pronounced, suggesting that endocrine regulation of oligosaccharide structure is dependent upon the maturational state of the animal. Together, these data provide direct evidence and characterization of specific changes in the structure of a secreted pituitary glycoprotein hormone occurring as a result of in vivo endocrine alterations during early development. Moreover, they provide a potential structural basis to explain the delayed clearance of both TSH and the gonadotropins with end-organ deficiency, which may have important implications for the in vivo biological activities of these hormones

  19. Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, Abdul, E-mail: abdulmajeed2276@gmail.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F. [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, King Saud University, PO Box 800, Riyadh 11421 (Saudi Arabia); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-06-15

    Rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm{sup −1.} Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b{sub VI}). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} ferrites. • The crystallite size was found

  20. Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

    International Nuclear Information System (INIS)

    Majeed, Abdul; Khan, Muhammad Azhar; Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F.; Murtaza, Ghulam; Akhtar, Majid Niaz; Shakir, Imran; Warsi, Muhammad Farooq

    2016-01-01

    Rare-earth (RE=La 3+ , Nd 3+ , Gd 3+ , Tb 3+ , Dy 3+ ) doped Ba 2 NiCoRE x Fe 28−x O 46 (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm −1. Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b VI ). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La 3+ , Nd 3+ , Gd 3+ , Tb 3+ , Dy 3+ ) doped Ba 2 NiCoRE x Fe 28−x O 46 (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba 2 NiCoRE x Fe 28−x O 46 ferrites. • The crystallite size was found in the range 7–19 nm. • The rare-earth incorporation enhanced the coercivity (664–926 Oe).

  1. Preoperative Serum Thyrotropin to Thyroglobulin Ratio Is Effective for Thyroid Nodule Evaluation in Euthyroid Patients.

    Science.gov (United States)

    Wang, Lina; Li, Hao; Yang, Zhongyuan; Guo, Zhuming; Zhang, Quan

    2015-07-01

    This study was designed to assess the efficiency of the serum thyrotropin to thyroglobulin ratio for thyroid nodule evaluation in euthyroid patients. Cross-sectional study. Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China. Retrospective analysis was performed for 400 previously untreated cases presenting with thyroid nodules. Thyroid function was tested with commercially available radioimmunoassays. The receiver operating characteristic curves were constructed to determine cutoff values. The efficacy of the thyrotropin:thyroglobulin ratio and thyroid-stimulating hormone for thyroid nodule evaluation was evaluated in terms of sensitivity, specificity, positive predictive value, positive likelihood ratio, negative likelihood ratio, and odds ratio. In receiver operating characteristic curve analysis, the area under the curve was 0.746 for the thyrotropin:thyroglobulin ratio and 0.659 for thyroid-stimulating hormone. With a cutoff point value of 24.97 IU/g for the thyrotropin:thyroglobulin ratio, the sensitivity, specificity, positive predictive value, positive likelihood ratio, and negative likelihood ratio were 78.9%, 60.8%, 75.5%, 2.01, and 0.35, respectively. The odds ratio for the thyrotropin:thyroglobulin ratio indicating malignancy was 5.80. With a cutoff point value of 1.525 µIU/mL for thyroid-stimulating hormone, the sensitivity, specificity, positive predictive value, positive likelihood ratio, and negative likelihood ratio were 74.0%, 53.2%, 70.8%, 1.58, and 0.49, respectively. The odds ratio indicating malignancy for thyroid-stimulating hormone was 3.23. Increasing preoperative serum thyrotropin:thyroglobulin ratio is a risk factor for thyroid carcinoma, and the correlation of the thyrotropin:thyroglobulin ratio to malignancy is higher than that for serum thyroid-stimulating hormone. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  2. Thyrotropin-producing pituitary adenoma simultaneously existing with Graves' disease: a case report.

    Science.gov (United States)

    Arai, Nobuhiko; Inaba, Makoto; Ichijyo, Takamasa; Kagami, Hiroshi; Mine, Yutaka

    2017-01-06

    Thyrotropin-producing pituitary tumor is relatively rare. In particular, concurrent cases associated with Graves' disease are extremely rare and only nine cases have been reported so far. We describe a case of a thyrotropin-producing pituitary adenoma concomitant with Graves' disease, which was successfully treated. A 40-year-old Japanese woman presented with mild signs of hyperthyroidism. She had positive anti-thyroid-stimulating hormone receptor antibody, anti-thyroglobulin antibody, and anti-thyroid peroxidase antibody. Her levels of serum thyroid-stimulating hormone, which ranged from low to normal in the presence of high levels of serum free thyroid hormones, were considered to be close to a state of syndrome of inappropriate secretion of thyroid-stimulating hormone. Magnetic resonance imaging showed a macropituitary tumor. The coexistence of thyrotropin-producing pituitary adenoma and Graves' disease was suspected. Initial therapy included anti-thyroid medication, which was immediately discontinued due to worsening symptoms. Subsequently, surgical therapy for the pituitary tumor was conducted, and her levels of free thyroid hormones, including the thyroid-stimulating hormone, became normal. On postoperative examination, her anti-thyroid-stimulating hormone receptor antibody levels decreased, and the anti-thyroglobulin antibody became negative. The coexistence of thyrotropin-producing pituitary adenoma and Graves' disease is rarely reported. The diagnosis of this condition is complicated, and the appropriate treatment strategy has not been clearly established. This case suggests that physicians should consider the coexistence of thyrotropin-producing pituitary adenoma with Graves' disease in cases in which thyroid-stimulating hormone values range from low to normal in the presence of thyrotoxicosis, and the surgical treatment of thyrotropin-producing pituitary adenoma could be the first-line therapy in patients with both thyrotropin-producing pituitary adenoma

  3. Processing of thyrotropin-releasing hormone prohormone (pro-TRH) generates a biologically active peptide, prepro-TRH-(160-169), which regulates TRH-induced thyrotropin secretion

    International Nuclear Information System (INIS)

    Bulant, M.; Vaudry, H.; Roussel, J.P.; Astier, H.; Nicolas, P.

    1990-01-01

    Rat thyrotropin-releasing hormone (TRH) prohormone contains five copies of the TRH progenitor sequence Gln-His-Pro-Gly linked together by connecting sequences whose biological activity is unknown. Both the predicted connecting peptide prepro-TRH-(160-169) (Ps4) and TRH are predominant storage forms of TRH precursor-related peptides in the hypothalamus. To determine whether Ps4 is co-released with TRH, rat median eminence slices were perfused in vitro. Infusion of depolarizing concentrations of KCl induced stimulation of release of Ps4- and TRH-like immunoreactivity. The possible effect of Ps4 on thyrotropin release was investigated in vitro using quartered anterior pituitaries. Infusion of Ps4 alone had no effect on thyrotropin secretion but potentiated TRH-induced thyrotropin release in a dose-dependent manner. In addition, the occurrence of specific binding sites for 125 I-labeled Tyr-Ps4 in the distal lobe of the pituitary was demonstrated by binding analysis and autoradiographic localization. These findings indicate that these two peptides that arise from a single multifunctional precursor, the TRH prohormone, act in a coordinate manner on the same target cells to promote hormonal secretion. These data suggest that differential processing of the TRH prohormone may have the potential to modulate the biological activity of TRH

  4. Multiple metals predict prolactin and thyrotropin (TSH) levels in men

    Energy Technology Data Exchange (ETDEWEB)

    Meeker, John D., E-mail: meekerj@umich.edu [Department of Environmental Health Sciences, University of Michigan School of Public Health, 6635 SPH Tower, 109 S. Observatory St., Ann Arbor, MI 48109 (United States); Rossano, Mary G. [Department of Animal and Food Sciences, University of Kentucky, Lexington, KY (United States); Protas, Bridget [Department of Epidemiology, Michigan State University, East Lansing, MI (United States); Diamond, Michael P.; Puscheck, Elizabeth [Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI (United States); Daly, Douglas [Grand Rapids Fertility and IVF, Grand Rapids, MI (United States); Paneth, Nigel [Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI (United States); Wirth, Julia J. [Department of Epidemiology, Michigan State University, East Lansing, MI (United States); Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI (United States)

    2009-10-15

    Exposure to a number of metals can affect neuroendocrine and thyroid signaling, which can result in adverse effects on development, behavior, metabolism, reproduction, and other functions. The present study assessed the relationship between metal concentrations in blood and serum prolactin (PRL) and thyrotropin (TSH) levels, markers of dopaminergic, and thyroid function, respectively, among men participating in a study of environmental influences on male reproductive health. Blood samples from 219 men were analyzed for concentrations of 11 metals and serum levels of PRL and TSH. In multiple linear regression models adjusted for age, BMI and smoking, PRL was inversely associated with arsenic, cadmium, copper, lead, manganese, molybdenum, and zinc, but positively associated with chromium. Several of these associations (Cd, Pb, Mo) are consistent with limited studies in humans or animals, and a number of the relationships (Cr, Cu, Pb, Mo) remained when additionally considering multiple metals in the model. Lead and copper were associated with non-monotonic decrease in TSH, while arsenic was associated with a dose-dependent increase in TSH. For arsenic these findings were consistent with recent experimental studies where arsenic inhibited enzymes involved in thyroid hormone synthesis and signaling. More research is needed for a better understanding of the role of metals in neuroendocrine and thyroid function and related health implications.

  5. Thyrotropin-releasing hormone (TRH) reverses hyperglycemia in rat

    International Nuclear Information System (INIS)

    Luo Luguang; Luo, John Z.Q.; Jackson, Ivor M.D.

    2008-01-01

    Hyperglycemia in thyrotropin-releasing hormone (TRH) null mice indicates that TRH is involved in the regulation of glucose homeostasis. Further, TRH levels in the pancreas peak during the stages of late embryonic and early neonatal β cell development. These observations are consistent in linking TRH to islet cell proliferation and differentiation. In this study, we examined the effect of TRH administration in damaged pancreatic rat (streptozotocin, STZ) to determine whether TRH could improve damaged pancreatic β cells function. We hypothesize that TRH is able to reverse STZ-induced hyperglycemia by increasing pancreatic islet insulin content, preventing apoptosis, and potentially induce islet regeneration. It was found that following intra-peritoneal (ip) injection, TRH (10 μg/kg body weight (bwt)) reverses STZ (65 mg/kg bwt)-induced hyperglycemia (TRH given 3 days after STZ injection). Increased circulating insulin levels and insulin content in extracted pancreas suggests that TRH reversed STZ-induced hyperglycemia through improving pancreatic islet β cell function. Further studies show a significantly lower level of apoptosis in islets treated with TRH as well as the presence of proliferation marker nestin and Brdu, suggesting that the TRH has the potential to prevent apoptosis and stimulate islet proliferation

  6. Serum Thyrotropin and Phase of the Menstrual Cycle

    Directory of Open Access Journals (Sweden)

    Salvatore Benvenga

    2017-09-01

    Full Text Available About one-fifth of patients treated with levothyroxine have serum thyrotropin (TSH above target concentrations but, in approximately 15% of them, the cause of this TSH insufficient normalization remains unknown. We report the cases of two regularly menstruating women with known thyroid disease who had TSH levels consistently >3 mU/L (and sometimes above target levels during mid-cycle, but consistently lower serum levels during the follicular and luteal phases of menstrual cycle. A major TSH release by the thyrotrophs in response to high circulating levels of estradiol (E2 at mid-cycle may increase levels of TSH compared to other phases of the cycle. The increased TSH can be misinterpreted as refractory hypothyroidism if the woman is under L-T4 replacement therapy or as subclinical hypothyroidism if the woman is not. Our findings might have important implications for diagnosis and management of thyroid disease, suggesting to request serum TSH measurements outside of the periovulatory days.

  7. Radioimmunoassay of thyrotropin releasing hormone in plasma and urine

    International Nuclear Information System (INIS)

    Saito, Shiro; Musa, Kimitaka; Yamamoto, Suzuyo; Oshima, Ichiyo; Funato, Toyohiko

    1975-01-01

    A sensitive and specific radioimmunoassay has been developed capable of measuring thyrotropin releasing hormone (TRH) in extracted human plasma and urine. All of three TRH analogues tested had little cross-reactivity to antibody. Luteinizing hormone releasing hormone, lysine vasopressin, rat growth hormone and bovine albumin were without effect, but rat hypothalamic extract produced a displacement curve which was parallel to that obtained with the synthetic TRH. Sensitivity of the radioimmunoassay was 4 pg per tube with intraassay coefficient of variation of 6.2-9.7%. Synthetic TRH could be quantitatively extracted by methanol when added to human plasma in concentration of 25, 50 and 100 pg/ml. TRH immunoreactivity was rapidly reduced in plasma at 20 0 C than at 0 0 C, but addition of peptidase inhibitors, FOY-007 and BAL, prevented the inactivation of TRH for 3 hr at 0 0 C. The TRH in urine was more stable at 0 0 C than 20 0 C, and recovered 75+-4.6% at 24 hr after being added. The plasma levels of TRH were 19 pg/ml or less in normal adults and no sex difference was observed. The rate of disappearance of TRH administered i.v. from the blood could be represented as half-times of 4-12 min. Between 5.3-12.3% of the injected dose was excreted into urine within 1 hr as an immunoreactive TRH. These results indicate the usefulness of TRH radioimmunoassay for clinical investigation. (auth.)

  8. Multiple metals predict prolactin and thyrotropin (TSH) levels in men

    International Nuclear Information System (INIS)

    Meeker, John D.; Rossano, Mary G.; Protas, Bridget; Diamond, Michael P.; Puscheck, Elizabeth; Daly, Douglas; Paneth, Nigel; Wirth, Julia J.

    2009-01-01

    Exposure to a number of metals can affect neuroendocrine and thyroid signaling, which can result in adverse effects on development, behavior, metabolism, reproduction, and other functions. The present study assessed the relationship between metal concentrations in blood and serum prolactin (PRL) and thyrotropin (TSH) levels, markers of dopaminergic, and thyroid function, respectively, among men participating in a study of environmental influences on male reproductive health. Blood samples from 219 men were analyzed for concentrations of 11 metals and serum levels of PRL and TSH. In multiple linear regression models adjusted for age, BMI and smoking, PRL was inversely associated with arsenic, cadmium, copper, lead, manganese, molybdenum, and zinc, but positively associated with chromium. Several of these associations (Cd, Pb, Mo) are consistent with limited studies in humans or animals, and a number of the relationships (Cr, Cu, Pb, Mo) remained when additionally considering multiple metals in the model. Lead and copper were associated with non-monotonic decrease in TSH, while arsenic was associated with a dose-dependent increase in TSH. For arsenic these findings were consistent with recent experimental studies where arsenic inhibited enzymes involved in thyroid hormone synthesis and signaling. More research is needed for a better understanding of the role of metals in neuroendocrine and thyroid function and related health implications.

  9. Evaluation of Six Different Immunoassays for Serum Thyrotropin

    International Nuclear Information System (INIS)

    Ma Donghong; Lu Hankui; Gao Yunchao; Ge Wenli; Xiong Jiang; Liu Qiaoping; Gu Qing

    2010-01-01

    To analyzes the discrepancy and association among six different thyrotropin (TSH) immunoassay methods and to study their impact on the clinical diagnoses of thyroid diseases, the 150 serum samples from three groups consisting of hyperthyroidism, hypothyroidism and healthy subjects, 50 samples in each group were included in this study. The serum TSH levels were measured simultaneously by radioimmunoassay (RIA), immunoradiometric assay (IRMA), three-type chemilumiminescence immunoassay (CLIA) and electrochemiluminescence immunoassay (ECLIA). The results showed that individual serum TSH level varied significantly from one assay to another. There was no correlation between TSH RIA and other five assays in groups of hyperthyroidism and healthy subjects(P>0.05). The correlations between TSH IRMA and four automatic assays in hyperthyroidism group were relatively low (r= 0.38∼0.41). However, among the four automatic assays, TSH levels were well correlated (r= 0.92∼0.99). For clinical diagnoses, TSH RIA alone was not useful in the differentiation of hyperthyroidism and normal subjects, and TSH IRMA was misleading in some hyperthyroidism. There were no significant differences for four TSH automatic immunoassays in differential diagnoses of thyroid diseases. (authors)

  10. Direct evidence that ganglioside is an integral component of the thyrotropin receptor

    International Nuclear Information System (INIS)

    Kielczynski, W.; Harrison, L.C.; Leedman, P.J.

    1991-01-01

    Gangliosides were extracted from purified human and porcine thyrotropin (TSH) receptors (TSH-R) and were detected by probing with an 125 I-labeled sialic acid-specific lectin, Limax flavus agglutinin. Gangliosides copurified with human and porcine TSH-R migrated between monosialoganglioside GM1 and disialoganglioside GD1a. Ceramide glycanase digestion of the purified human TSH-R-associated glycolipid confirmed its ganglioside nature. It was resistant to Vibrio cholerae sialidase, which digest all gangliosides except GM1, but was sensitive to Arthrobacter ureafaciens sialidase, which digests all gangliosides including GM1. These findings indicate that the human TSH-R contains ganglioside that belongs to the galactosyl(β1→ 3)-N-acetylgalactosaminyl(β1→ 4)-[N-acetylneuraminyl(α2→ 3)]galactosyl(β1 → 4)glucosyl(β1 → 1)ceramide (GM1) family. Its intimate association with receptor protein implies a key role for ganglioside in the structure and function of the TSH-R

  11. Hyperthyroidism and acromegaly due to a thyrotropin- and growth hormone-secreting pituitary tumor. Lack of hormonal response to bromocriptine.

    Science.gov (United States)

    Carlson, H E; Linfoot, J A; Braunstein, G D; Kovacs, K; Young, R T

    1983-05-01

    A 47-year-old woman with acromegaly and hyperthyroidism was found to have an inappropriately normal serum thyrotropin level (1.5 to 2.5 microU/ml) that responded poorly to thyrotropin-releasing hormone but showed partial responsiveness to changes in circulating thyroid hormones. Serum alpha-subunit levels were high-normal and showed a normal response to thyrotropin-releasing hormone. Growth hormone and thyrotropin hypersecretion persisted despite radiotherapy and bromocriptine treatment. Selective trans-sphenoidal removal of a pituitary adenoma led to normalization of both growth hormone and thyrotropin levels. Both thyrotropes and somatotropes were demonstrated in the adenoma by the immunoperoxidase technique and electron microscopy.

  12. The thyroid nodule. Thyrotropin and peripheral thyroid hormones; Der Schilddruesenknoten. TSH und periphere Hormone

    Energy Technology Data Exchange (ETDEWEB)

    Zimny, M. [Klinikum Hanau (Germany). Inst. fuer Nuklearmedizin

    2008-09-15

    Thyrotropin, free triodothyronine and thyroxine represent the standard serological parameters for the diagnostic work-up of the thyroid but only a minority of thyroid nodules present with subclinical or overt thyroid disorders. Besides a review of the regulation and principle of function of thyroid hormones as well as the effects of subclinical or overt hyperthyroidism, the significant role of these parameters beyond the assessment of hyperthyroidism in thyroid nodules is discussed. There is evidence that the level of thyrotropin within the normal range is predictive for the relevance of autonomous functioning nodules and the risk of malignancy of non-functioning thyroid nodules. Furthermore, the ratio of triodothyronine and thyroxine indicates the etiology of hyperthyroidism. Thyrotropin represents the main parameter to determine the adequate dose of thyroid hormone therapy of thyroid nodules. (orig.)

  13. A different approach to the radioimmunoassay of thyrotropin releasing hormone

    International Nuclear Information System (INIS)

    Visser, T.J.; Klootwijk, W.; Docter, R.; Hennemann, G.

    1977-01-01

    Thyrotropin releasing hormone (TRH) was linked to hemocyanin by means of a dinitrophenylene moiety. TRH (pGlu-His-Pro-NH 2 ) was made to react with a large excess of 1,5-difluoro-2,4-dinitrobenzene to yield Nsup(im)-[5-fluoro-2,4-dinitrophenyl]TRH. After removal of excess reagent the derivative was coupled to hemocyanin with a minimum of side-reactions. From two rabbits out of four immunized with this material valuable antisera were obtained, which were used in the radioimmunoassay of the hypothalamic hormone at a final dilution of 1:7,500 and 1:15,000, respectively. The properties, especially with regard to specificity, of these antisera were studied and compared with another antiserum, which was obtained using a conjugate having TRH linked to thyroglobulin via a p-azophenyl-acetyl moiety. Despite the difference between the derivatives, i.e. the nature and the point of attachment of the side chains, the specificities of the assays were very similar. Deamidation of TRH, deletion of either one of the terminal residues, hydrolysis of the lactam of the pyroglutamyl residue, and replacing Pro-NH 2 by Pro-Gly-NH 2 or by an octapeptide chain yield peptides with strongly diminished cross-reactivities. However, Nsup(im)-benzyl-TRH and pGlu-Phe-Pro-NH 2 were 5-10 times as active as TRH probably due to a closer physico-chemical similarity to the arrangement of the haptens in the conjugates. This suggests that the sensitivity of the radioimmunoassay may be increased markedly by conversion of TRH into the Nsup(im)-dinitrophenyl derivative and by using a related compound for radioiodination. (orig.) [de

  14. Clinical characteristics of patients with thyrotropin-secreting pituitary adenoma.

    Science.gov (United States)

    Wu, Yung-Yen; Chang, Hung-Yu; Lin, Jen-Der; Chen, Kwang-Wen; Huang, Yu-Yao; Jung, Shih-Ming

    2003-03-01

    Thyroid-stimulating hormone (thyrotropin, TSH)-secreting pituitary adenoma is a very rare cause of hyperthyroidism. Diagnosis of this condition is often delayed due to lack of availability of TSH radioimmunoassay (RIA), the failure to recognize the utility of RIA and the incorrect attribution of the condition to other causes of thyrotoxicosis. This retrospective study analyzed the clinical characteristics of patients with this disorder treated from 1991 to 2002. Seven patients (6 females, 1 male; mean age, 48 years; range, 33 to 72 years) with a diagnosis of TSHsecreting pituitary adenoma based on detectable TSH levels with high serum free thyroid hormone or triiodothyronine concentrations and pituitary lesions found on neuroimaging were included in this study. Patient records including clinical features, endocrine studies, immunohistochemistry studies, and response to treatment were reviewed. All 7 patients had hyperthyroidism, elevated free thyroxine or triiodothyronine levels, and unsuppressed levels of TSH. Imaging studies demonstrated a pituitary mass or lesion in all patients. Six patients had macroadenomas and 1 patient had a microadenoma. One of the patients had coexisting acromegalic features and hypersecretion of growth hormone was diagnosed. All of the patients had been treated with thionamides or thyroidectomy for presumed primary hyperthyroidism. Serum alpha-subunit level was uncharacteristically normal in 2 patients and elevated in 1 patient. Alpha-subunit/TSH molar ratios were elevated in 3 patients. Five patients underwent transsphenoidal adenomectomy but only one of them remained well-controlled at follow-up. Three patients received administration of somatostatin analogs and they achieved normalization of serum TSH and free thyroid hormones during the period of therapy. TSH immunoassay has an important role in the evaluation of hyperthyroid patients to determine the presence of inappropriate secretion. TSH-secreting pituitary adenoma exhibits

  15. Structural and quantum mechanical computations to elucidate the altered binding mechanism of metal and drug with pyrazinamidase from Mycobacterium tuberculosis due to mutagenicity.

    Science.gov (United States)

    Rasool, Nouman; Iftikhar, Saima; Amir, Anam; Hussain, Waqar

    2018-03-01

    Pyrazinamide is known to be the most effective treatment against tuberculosis disease and is known to have bacteriostatic action. By targeting the bacterial spores, this drug reduces the chances for the progression of the infection in organisms. In recent years, increased instances of the drug resistance of bacterial strains are reported. Pyrazinamidase, activator for pyrazinamide, leads to resistance against the drug due to mutagenicity across the world. The present study aimed at the quantum mechanistic analysis of mutations in pyrazinamidase to gain insights into the mechanism of this enzyme. Quantum mechanical calculations were performed to analyse the effect of mutations at the metal coordination site using ORCA software program. Moreover, conformational changes in PZase binding cavity has also been analysed due to mutations of binding pocket residues using CASTp server. In order to elucidate the behaviour of the mutant pyrazinamidase, docking of PZA in the binding pocket of PZase was performed using AutoDock Vina. Analysis of results revealed that iron showed weak binding with the metal coordination site of the mutant proteins due to alteration in electron transfer mechanism. The binding cavity of the mutant PZase has undergone major conformational changes as the volume of pocket increased due to bulky R-chains of mutated amino acids. These conformational changes lead to weak binding of the drug at binding cavity of PZase and reduce the drug activation mechanism leading to increased drug resistance in the bacterial strains. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Results of quality control surveys of radioimmunological determinations of thyrotropin in newborns

    International Nuclear Information System (INIS)

    Roehle, G.; Kruse, R.; Voigt, U.; Torresani, T.

    1983-01-01

    Within the quality control scheme of the Deutsche Gesellschaft fuer Klinische Chemie, seven quality control surveys of thyrotropin (TSH) determinations in blood dried on filter paper have been carried out since 1980. Ninety-six screening laboratories from 12 European countries took part in these surveys. In a single survey each participant usually analysed four different samples; each of these consisted of three spots of dried blood spiked with defined amounts of thyrotropin. For the evaluations of the surveys the participants were asked to give information about their analytical results, and from these, their diagnostic classifications. The medians of the analytical results correlated well with the given thyrotropin concentrations, but the individual estimations from different laboratories varied greatly. Major discrepancies of classification were also apparent, both in the given thyrotropin concentrations and in the individual estimations. Two special collaborative studies with nine selected laboratories showed on the one hand that analysis of the largest possible part of the dried blood sample can help to optimize the precision of the results; on the other hand, considerable drawbacks related to the reagents and the methods were sometimes observed. (orig.) [de

  17. Parity and 11-Year Serum Thyrotropin and Thyroid Autoantibody Change: A Longitudinal Population-Based Study

    DEFF Research Database (Denmark)

    Bjergved, Lena; Carlé, Allan; Jørgensen, Torben

    2016-01-01

    thyrotropin (TSH), as well as change in thyroid peroxidase autoantibody (TPOAb) status. A random sample of 4649 people aged 18-65 years participated in a population-based study in the period 1997-1998. In the study presented here, 1749 non-pregnant women with no history of thyroid disease were included who...

  18. Preparation of standards of triiodothyronine, thyroxine and thyrotropin; Prepracion de estandares de triyodotironina, tiroxina y tirotrofina

    Energy Technology Data Exchange (ETDEWEB)

    Lavalley E, C.; Delgado S, B.; Ruiz J, A.; Zambrano A, F

    1991-10-15

    The standards preparation requires of certain basic principles, some of which are described in this work, which was made with the purpose of establishing the most appropriate conditions for the preparation of standards of triiodothyronine, thyroxine and thyrotropin to be used in radioimmunoanalysis essays. The diverse standards show a balanced displacement, that which is observed in the graphs presented in this work. (Author)

  19. Effects of thyrotropin-releasing hormone on regional cerebral blood flow in man

    DEFF Research Database (Denmark)

    Oturai, P S; Friberg, L; Sam, I

    1992-01-01

    emission computerized tomograph and inhalation of 133Xe. Thyrotropin-releasing hormone caused a significant mean increase of 3.7% (range -8.8-22.7) in blood flow in a region consistent with the left thalamus compared to placebo (3.2% decrease). In 25 other regions no significant change was detected...

  20. Clinical Value of Thyrotropin Receptor Antibodies for the Differential Diagnosis of Interferon Induced Thyroiditis.

    Science.gov (United States)

    Benaiges, D; Garcia-Retortillo, M; Mas, A; Cañete, N; Broquetas, T; Puigvehi, M; Chillarón, J J; Flores-Le Roux, J A; Sagarra, E; Cabrero, B; Zaffalon, D; Solà, R; Pedro-Botet, J; Carrión, J A

    2016-01-01

    The clinical value of thyrotropin receptor antibodies for the differential diagnosis of thyrotoxicosis induced by pegylated interferon-alpha remains unknown. We analyzed the diagnostic accuracy of thyrotropin receptor antibodies in the differential diagnosis of thyrotoxicosis in patients with chronic hepatitis C (CHC) receiving pegylated interferon-alpha plus ribavirin. Retrospective analysis of 274 patients with CHC receiving pegylated interferon-alpha plus ribavirin. Interferon-induced thyrotoxicosis was classified according to clinical guidelines as Graves disease, autoimmune and non- autoimmune destructive thyroiditis. 48 (17.5%) patients developed hypothyroidism, 17 (6.2%) thyrotoxicosis (6 non- autoimmune destructive thyroiditis, 8 autoimmune destructive thyroiditis and 3 Graves disease) and 22 "de novo" thyrotropin receptor antibodies (all Graves disease, 2 of the 8 autoimmune destructive thyroiditis and 17 with normal thyroid function). The sensitivity and specificity of thyrotropin receptor antibodies for Graves disease diagnosis in patients with thyrotoxicosis were 100 and 85%, respectively. Patients with destructive thyroiditis developed hypothyroidism in 87.5% of autoimmune cases and in none of those with a non- autoimmune etiology (pthyroid scintigraphy for the differential diagnosis of thyrotoxicosis in CHC patients treated with pegylated interferon. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Effect of Thyrotropin Suppression Therapy on Bone in Thyroid Cancer Patients.

    Science.gov (United States)

    Papaleontiou, Maria; Hawley, Sarah T; Haymart, Megan R

    2016-02-01

    The thyroid cancer incidence is rising. Despite current guidelines, controversy exists regarding the degree and duration of thyrotropin suppression therapy. Also, its potential skeletal effects remain a concern to physicians caring for thyroid cancer patients. We conducted a review of published data to evaluate existing studies focusing on the skeletal effects of thyrotropin suppression therapy in thyroid cancer patients. A systematic search of the PubMed, Ovid/Medline, and Cochrane Central Register of Controlled Trials databases was conducted. The retained studies were evaluated for methodological quality, and the study populations were categorized into premenopausal women, postmenopausal women, and men. Twenty-five pertinent studies were included. Seven studies were longitudinal and 18 were cross-sectional. Of the 25 included studies, 13 were assigned an excellent methodological quality score. Three of 5 longitudinal studies and 3 of 13 cross-sectional studies reported decreased bone mineral density (BMD) in premenopausal women; 2 of 4 longitudinal studies and 5 of 13 cross-sectional studies reported decreased BMD in postmenopausal women. The remaining studies showed no effect on BMD. The only longitudinal study of men showed bone mass loss; however, cross-sectional studies of men did not demonstrate a similar effect. Studies to date have yielded conflicting results on the skeletal effects of thyrotropin suppression therapy and a knowledge gap remains, especially for older adults and men. Existing data should be cautiously interpreted because of the variable quality and heterogeneity. Identifying groups at risk of adverse effects from thyrotropin suppression therapy will be instrumental to providing focused and tailored thyroid cancer treatment. The standard treatment for thyroid cancer includes total thyroidectomy with or without radioactive iodine ablation, often followed by thyrotropin suppression therapy. Despite current guidelines, controversy exists

  2. Elucidating structural order and disorder phenomena in mullite-type Al4B2O9 by automated electron diffraction tomography

    International Nuclear Information System (INIS)

    Zhao, Haishuang; Krysiak, Yaşar; Hoffmann, Kristin; Barton, Bastian; Molina-Luna, Leopoldo; Neder, Reinhard B.; Kleebe, Hans-Joachim; Gesing, Thorsten M.; Schneider, Hartmut; Fischer, Reinhard X.

    2017-01-01

    The crystal structure and disorder phenomena of Al 4 B 2 O 9 , an aluminum borate from the mullite-type family, were studied using automated diffraction tomography (ADT), a recently established method for collection and analysis of electron diffraction data. Al 4 B 2 O 9 , prepared by sol-gel approach, crystallizes in the monoclinic space group C2/m. The ab initio structure determination based on three-dimensional electron diffraction data from single ordered crystals reveals that edge-connected AlO 6 octahedra expanding along the b axis constitute the backbone. The ordered structure (A) was confirmed by TEM and HAADF-STEM images. Furthermore, disordered crystals with diffuse scattering along the b axis are observed. Analysis of the modulation pattern implies a mean superstructure (AAB) with a threefold b axis, where B corresponds to an A layer shifted by ½a and ½c. Diffraction patterns simulated for the AAB sequence including additional stacking disorder are in good agreement with experimental electron diffraction patterns. - Graphical abstract: Crystal structure and disorder phenomena of B-rich Al 4 B 2 O 9 studied by automated electron diffraction tomography (ADT) and described by diffraction simulation using DISCUS. - Highlights: • Ab-initio structure solution by electron diffraction from single nanocrystals. • Detected modulation corresponding mainly to three-fold superstructure. • Diffuse diffraction streaks caused by stacking faults in disordered crystals. • Observed streaks explained by simulated electron diffraction patterns.

  3. Endogenous Thyrotropin and Triiodothyronine Concentrations in Individuals with Thyroid Cancer

    Science.gov (United States)

    Nsouli-Maktabi, Hala; Soldin, Steven J.

    2008-01-01

    Background Thyroid hormone suppression therapy is associated with decreased recurrence rates and improved survival in patients with differentiated thyroid cancer. Recently higher baseline thyrotropin (TSH) levels have been found to be associated with a postoperative diagnosis of differentiated thyroid cancer. Our objective was to confirm whether preoperative TSH levels were higher in patients who were diagnosed with differentiated thyroid cancer after undergoing thyroidectomy, compared with patients who were found to have benign disease. We also sought to determine whether thyroid hormone levels were lower in the patients with malignancy. Methods The study was a retrospective analysis of a prospective study. The study setting was the General Clinical Research Center of an Academic Medical Center. Participants were 50 euthyroid patients undergoing thyroidectomy. Thyroxine, triiodothyronine (T3), and TSH levels were documented in patients prior to their scheduled thyroidectomy. Following thyroidectomy, patients were divided into those with a histologic diagnosis of either differentiated thyroid cancer or benign disease. Preoperative thyroid profiles were correlated with patients' postoperative diagnoses. Results All patients had a normal serum TSH concentration preoperatively. One-third of the group was diagnosed with thyroid cancer as a result of their thyroidectomy. These patients had a higher serum TSH level (mean = 1.50 mIU/L, CI 1.22–1.78 mIU/L) than patients with benign disease (mean = 1.01 mIU/mL, CI 0.84–1.18 mIU/L). There was a greater risk of having thyroid cancer in patients with TSH levels in the upper three quartiles of TSH values, compared with patients with TSH concentrations in the lowest quartile of TSH values (odd ratio = 8.7, CI 2.2–33.7). Patients with a thyroid cancer diagnosis also had lower T3 concentrations measured by liquid chromatography tandem mass spectrometry (mean = 112.6 ng/dL, CI 103.8–121.4

  4. Synthesis and structure elucidation of a series of pyranochromene chalcones and flavanones using 1D and 2D NMR spectroscopy and X-ray crystallography.

    Science.gov (United States)

    Pawar, Sunayna S; Koorbanally, Neil A

    2014-06-01

    A series of novel pyranochromene chalcones and corresponding flavanones were synthesized. This is the first report on the confirmation of the absolute configuration of chromene-based flavanones using X-ray crystallography. These compounds were characterized by 2D NMR spectroscopy, and their assignments are reported herein. The 3D structure of the chalcone 3b and flavanone 4g was determined by X-ray crystallography, and the structure of the flavanone was confirmed to be in the S configuration at C-2. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Elucidating a Key Anti-HIV-1 and Cancer-Associated Axis: The Structure of CCL5 (Rantes) in Complex with CCR5

    Science.gov (United States)

    Tamamis, Phanourios; Floudas, Christodoulos A.

    2014-06-01

    CCL5 (RANTES) is an inflammatory chemokine which binds to chemokine receptor CCR5 and induces signaling. The CCL5:CCR5 associated chemotactic signaling is of critical biological importance and is a potential HIV-1 therapeutic axis. Several studies provided growing evidence for the expression of CCL5 and CCR5 in non-hematological malignancies. Therefore, the delineation of the CCL5:CCR5 complex structure can pave the way for novel CCR5-targeted drugs. We employed a computational protocol which is primarily based on free energy calculations and molecular dynamics simulations, and report, what is to our knowledge, the first computationally derived CCL5:CCR5 complex structure which is in excellent agreement with experimental findings and clarifies the functional role of CCL5 and CCR5 residues which are associated with binding and signaling. A wealth of polar and non-polar interactions contributes to the tight CCL5:CCR5 binding. The structure of an HIV-1 gp120 V3 loop in complex with CCR5 has recently been derived through a similar computational protocol. A comparison between the CCL5 : CCR5 and the HIV-1 gp120 V3 loop : CCR5 complex structures depicts that both the chemokine and the virus primarily interact with the same CCR5 residues. The present work provides insights into the blocking mechanism of HIV-1 by CCL5.

  6. Elucidating structural order and disorder phenomena in mullite-type Al{sub 4}B{sub 2}O{sub 9} by automated electron diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haishuang; Krysiak, Yaşar [Institute of Inorganic Chemistry and Analytical Chemistry, Jakob-Welder-Weg 11, Johannes Gutenberg-University Mainz, 55128 Mainz (Germany); Hoffmann, Kristin [Crystallography, Department of Geosciences, Klagenfurter Str. 2, GEO, University of Bremen, 28359 Bremen (Germany); Institute of Inorganic Chemistry and Crystallography, Leobener Str. NW2, University of Bremen, 28359 Bremen (Germany); Barton, Bastian [Institute of Inorganic Chemistry and Analytical Chemistry, Jakob-Welder-Weg 11, Johannes Gutenberg-University Mainz, 55128 Mainz (Germany); Molina-Luna, Leopoldo [Department of Materials and Geoscience, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt (Germany); Neder, Reinhard B. [Department of Physics, Lehrstuhl für Kristallographie und Strukturphysik, Friedrich-Alexander University Erlangen-Nürnberg, Staudtstr.3, 91058 Erlangen (Germany); Kleebe, Hans-Joachim [Department of Materials and Geoscience, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt (Germany); Gesing, Thorsten M. [Institute of Inorganic Chemistry and Crystallography, Leobener Str. NW2, University of Bremen, 28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstr.1, University of Bremen, 28359 Bremen (Germany); Schneider, Hartmut [Crystallography, Department of Geosciences, Klagenfurter Str. 2, GEO, University of Bremen, 28359 Bremen (Germany); Fischer, Reinhard X. [Crystallography, Department of Geosciences, Klagenfurter Str. 2, GEO, University of Bremen, 28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstr.1, University of Bremen, 28359 Bremen (Germany); and others

    2017-05-15

    The crystal structure and disorder phenomena of Al{sub 4}B{sub 2}O{sub 9}, an aluminum borate from the mullite-type family, were studied using automated diffraction tomography (ADT), a recently established method for collection and analysis of electron diffraction data. Al{sub 4}B{sub 2}O{sub 9}, prepared by sol-gel approach, crystallizes in the monoclinic space group C2/m. The ab initio structure determination based on three-dimensional electron diffraction data from single ordered crystals reveals that edge-connected AlO{sub 6} octahedra expanding along the b axis constitute the backbone. The ordered structure (A) was confirmed by TEM and HAADF-STEM images. Furthermore, disordered crystals with diffuse scattering along the b axis are observed. Analysis of the modulation pattern implies a mean superstructure (AAB) with a threefold b axis, where B corresponds to an A layer shifted by ½a and ½c. Diffraction patterns simulated for the AAB sequence including additional stacking disorder are in good agreement with experimental electron diffraction patterns. - Graphical abstract: Crystal structure and disorder phenomena of B-rich Al{sub 4}B{sub 2}O{sub 9} studied by automated electron diffraction tomography (ADT) and described by diffraction simulation using DISCUS. - Highlights: • Ab-initio structure solution by electron diffraction from single nanocrystals. • Detected modulation corresponding mainly to three-fold superstructure. • Diffuse diffraction streaks caused by stacking faults in disordered crystals. • Observed streaks explained by simulated electron diffraction patterns.

  7. Lanthanide complexes of macrocyclic polyoxovanadates by VO4 units: synthesis, characterization, and structure elucidation by X-ray crystallography and EXAFS spectroscopy.

    Science.gov (United States)

    Nishio, Masaki; Inami, Shinnosuke; Katayama, Misaki; Ozutsumi, Kazuhiko; Hayashi, Yoshihito

    2012-01-16

    Reactions of a tetravanadate anion, [V(4)O(12)](4-), with a series of lanthanide(III) salts yield three types of lanthanide complexes of macrocyclic polyoxovanadates: (Et(4)N)(6)[Ln(III)V(9)O(27)] [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6)], (Et(4)N)(5)[(H(2)O)Ho(III)(V(4)O(12))(2)] (7), and (Et(4)N)(7)[Ln(III)V(10)O(30)] [Ln = Er (8), Tm (9), Yb (10), Lu (11)]. Lanthanide complexes 1-11 are isolated and characterized by IR, elemental analysis, single-crystal X-ray diffraction, and extended X-ray absorption fine structure spectroscopy (EXAFS). Lanthanide complexes 1-6 are composed of a square-antiprism eight-coordinated Ln(III) center with a macrocyclic polyoxovanadate that is constructed from nine VO(4) tetrahedra through vertex sharing. The structure of 7 is composed of a seven-coordinated Ho(III) center, which exhibits a capped trigonal-prism coordination environment by the sandwiching of two cyclic tetravanadates with a capping H(2)O ligand. Lanthanide complexes 8-11 have a six-coordinated Ln(III) center with a 10-membered vanadate ligand. The structural trend to adopt a larger coordination number for a larger lanthanide ion among the three types of structures is accompanied by a change in the vanadate ring sizes. These lanthanide complexes are examined by EXAFS spectroscopies on lanthanide L(III) absorption edges, and the EXAFS oscillations of each of the samples in the solid state and in acetonitrile are identical. The Ln-O and Ln···V bond lengths obtained from fits of the EXAFS data are consistent with the data from the single-crystal X-ray studies, reflecting retention of the structures in acetonitrile.

  8. Exploring 3D non-interpenetrated metal-organic framework with malonate-bridged Co(II) coordination polymer: structural elucidation and theoretical study

    Science.gov (United States)

    Hossain, Anowar; Mandal, Tripti; Mitra, Monojit; Manna, Prankrishna; Bauzá, Antonio; Frontera, Antonio; Seth, Saikat Kumar; Mukhopadhyay, Subrata

    2017-12-01

    A Co(II)-based coordination polymer with tetranuclear cobalt(II)-malonate cluster has been easily generated by aqueous medium self-assembly from Cobalt(II) chloride hexahydrate and malonic acid. The structure exhibits a non-interpenetrating, highly undulating two-dimensional (2D) bi-layer network with (4,4) topology. The crystal structure is composed of infinite interdigitated 2D metal-organic bi-layers which extended to an intricate 3D framework through the interbilayer hydrogen bonds. We have studied energetically by means of Density Functional Theory (DFT) calculations the H-bonding interactions that connect the 2D metal-organic bi-layers. The finite theoretical models have been used to compute conventional O‒H•••O and unconventional C‒H•••O interactions which plays a key role to build 3D architecture.

  9. Isolation and structure elucidation of a new indole alkaloid from Rauvolfia serpentina hairy root culture: the first naturally occurring alkaloid of the raumacline group.

    Science.gov (United States)

    Sheludko, Yuri; Gerasimenko, Irina; Kolshorn, Heinz; Stöckigt, Joachim

    2002-05-01

    A new monoterpenoid indole alkaloid, 10-hydroxy- N(alpha)-demethyl-19,20-dehydroraumacline ( 1), was isolated as a mixture of E- and Z-isomers from hairy root culture of Rauvolfia serpentina Benth. ex Kurz (Apocynaceae) and the structure was determined by 1D and 2D NMR analyses. The new indole alkaloid represents the first naturally occurring alkaloid of the raumacline group and its putative biosynthetical pathway is discussed.

  10. Structural Elucidation of cis / trans Dicaffeoylquinic Acid Photoisomerization Using Ion Mobility Spectrometry-Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Xueyun; Renslow, Ryan S.; Makola, Mpho M.; Webb, Ian K.; Deng, Liulin; Thomas, Dennis G.; Govind, Niranjan; Ibrahim, Yehia M.; Kabanda, Mwadham M.; Dubery, Ian A.; Heyman, Heino M.; Smith, Richard D.; Madala, Ntakadzeni E.; Baker, Erin S.

    2017-03-15

    Due to the recently uncovered health benefits and anti-HIV activities of dicaffeoylquinic acids (diCQAs), understanding their structures and functions is of great interest for drug discovery efforts. DiCQAs are analytically challenging to identify and quantify since they commonly exist as a diverse mixture of positional and geometric (cis/trans) isomers. In this work, we utilized ion mobility spectrometry coupled with mass spectrometry to separate the various isomers before and after UV irradiation. The experimental collision cross sections were then compared with theoretical structures to differentiate and identify the diCQA isomers. Our analyses found that naturally the diCQAs existed predominantly as trans/trans isomers, but after 3 h of UV irradiation, cis/cis, cis/trans, trans/cis, and trans/trans isomers were all present in the mixture. This is the first report of successful differentiation of cis/trans diCQA isomers individually, which shows the great promise of IMS coupled with theoretical calculations for determining the structure and activity relationships of different isomers in drug discovery studies.

  11. Structure elucidation of neutral, di-, tri-, and tetraglycosylceramides from High Five cells: identification of a novel (non-arthro-series) glycosphingolipid pathway

    DEFF Research Database (Denmark)

    Fuller, Matthew D; Schwientek, Tilo; Wandall, Hans H

    2005-01-01

    tetraglycosylceramide (Glcbeta1Cer --> Manbeta4Glcbeta1Cer [MacCer] --> GlcNAcbeta3Manbeta4Glcbeta1Cer [At(3)Cer] --> GalNAcbeta4- GlcNAcbeta3Manbeta4Glcbeta1Cer [At(4)Cer]). Surprisingly, the structures of the major neutral High Five GSLs already diverge from the arthro-series pathway at the level...... of the triglycosylceramide. Studies by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization mass spectrometry (ESI-MS) showed the structure of the predominant High Five triglycosylceramide to be Galbeta3Manbeta4Glcbeta1Cer, whereas the predominant tetraglycosylceramide...... was characterized as GalNAcalpha4Galbeta3Manbeta4- Glcbeta1Cer. Both of these structures are novel products for any cell or organism so far studied. The GalNAcalpha4 and Galbeta3 units are found in insect GSLs, but always as the fifth and sixth residues linked to GalNAcbeta4 in the arthro-series penta...

  12. Elucidating Structure-Bioactivity Relationships of Methyl-Branched Alkanes in the Contact Sex Pheromone of the Parasitic Wasp Lariophagus distinguendus

    Directory of Open Access Journals (Sweden)

    Stephan Kühbandner

    2013-12-01

    Full Text Available The exoskeletons of insects are covered by complex mixtures of cuticular hydrocarbons (CHCs which are involved in social and sexual communication. However, little is known about the relationship between the structures of CHCs and their behavioral activity. The key component of the contact sex pheromone of the parasitoid Lariophagus distinguendus is 3-methylheptacosane (3-MeC27, which is present in CHC profiles of both females and newly emerged males. The CHCs of females and young males elicit wing-fanning behavior in older males. However, as young males age, 3-MeC27 disappears from their CHC profiles and they no longer elicit wing-fanning responses from other males. We applied enantiopure 3-MeC27 and structurally related CHCs (with respect to chain length or methyl-branch position to the cuticle of aged male dummies and recorded the wing-fanning behavior of responding males. Only the two enantiomers of 3-MeC27 restored the dummies’ attractiveness. The addition of structurally related CHCs or various n-alkanes to bioactive dummies of young males and females significantly decreased wing-fanning by test males. Hence, L. distinguendus males respond specifically but not enantioselectively to 3-MeC27, and perceive the CHC profiles as a whole. Both removal (as is the case with 3-MeC27 in aging males and addition of individual compounds may disrupt the behavioral response.

  13. Structural modelling and molecular dynamics of a multi-stress responsive WRKY TF-DNA complex towards elucidating its role in stress signalling mechanisms in chickpea.

    Science.gov (United States)

    Konda, Aravind Kumar; Farmer, Rohit; Soren, Khela Ram; P S, Shanmugavadivel; Setti, Aravind

    2017-07-28

    Chickpea is a premier food legume crop with high nutritional quality and attains prime importance in the current era of 795 million people being undernourished worldwide. Chickpea production encounters setbacks due to various stresses and understanding the role of key transcription factors (TFs) involved in multiple stresses becomes inevitable. We have recently identified a multi-stress responsive WRKY TF in chickpea. The present study was conducted to predict the structure of WRKY TF to identify the DNA-interacting residues and decipher DNA-protein interactions. Comparative modelling approach produced 3D model of the WRKY TF with good stereochemistry, local/global quality and further revealed W19, R20, K21, and Y22 motifs within a vicinity of 5 Å to the DNA amongst R18, G23, Q24, K25, Y36, Y37, R38 and K47 and these positions were equivalent to the 2LEX WRKY domain of Arabidopsis. Molecular simulations analysis of reference protein -PDB ID 2LEX, along with Car-WRKY TF modelled structure with the DNA coordinates derived from PDB ID 2LEX and docked using HADDOCK were executed. Root Mean Square (RMS) Deviation and RMS Fluctuation values yielded consistently stable trajectories over 50 ns simulation. Strengthening the obtained results, neither radius of gyration, distance and total energy showed any signs of DNA-WRKY complex falling apart nor any significant dissociation event over 50 ns run. Therefore, the study provides first insights into the structural properties of multi-stress responsive WRKY TF-DNA complex in chickpea, enabling genome wide identification of TF binding sites and thereby deciphers their gene regulatory networks.

  14. Elucidating the 3D structures of Al(iii)-Aβ complexes: a template free strategy based on the pre-organization hypothesis.

    Science.gov (United States)

    Mujika, Jon I; Rodríguez-Guerra Pedregal, Jaime; Lopez, Xabier; Ugalde, Jesus M; Rodríguez-Santiago, Luis; Sodupe, Mariona; Maréchal, Jean-Didier

    2017-07-01

    Senile plaques are extracellular deposits found in patients with Alzheimer's Disease (AD) and are mainly formed by insoluble fibrils of β-amyloid (Aβ) peptides. The mechanistic details about how AD develops are not fully understood yet, but metals such as Cu, Zn, or Fe are proposed to have a non-innocent role. Many studies have also linked the non biological metal aluminum with AD, a species whose concentration in the environment and food has been constantly increasing since the industrial revolution. Gaining a molecular picture of how Al(iii) interacts with an Aβ peptide is of fundamental interest to improve understanding of the many variables in the evolution of AD. So far, no consensus has been reached on how this metal interacts with Aβ, partially due to the experimental complexity of detecting and quantifying the resulting Al(iii)-Aβ complexes. Computational chemistry arises as a powerful alternative to investigate how Al(iii) can interact with Aβ peptides, as suitable strategies could shed light on the metal-peptide description at the molecular level. However, the absence of any reliable template that could be used for the modeling of the metallopeptide structure makes computational insight extremely difficult. Here, we present a novel strategy to generate accurate 3D models of the Al(iii)-Aβ complexes, which still circumvents first principles simulations of metal binding to peptides of Aβ. The key to this approach lies in the identification of experimental structures of the isolated peptide that are favourably pre-organized for the binding of a given metal in configurations of the first coordination sphere that were previously identified as the most stable with amino acid models. This approach solves the problem of the absence of clear structural templates for novel metallopeptide constructs. The posterior refinement of the structures via QM/MM and MD calculations allows us to provide, for the first time, physically sound models for Al

  15. Quinolactacins A, B and C: novel quinolone compounds from Penicillium sp. EPF-6. II. Physico-chemical properties and structure elucidation.

    Science.gov (United States)

    Takahashi, S; Kakinuma, N; Iwai, H; Yanagisawa, T; Nagai, K; Suzuki, K; Tokunaga, T; Nakagawa, A

    2000-11-01

    Three novel quinolone compounds, quinolactacins A (1), B (2) and C (3), have been found from the fermentation broth of Penicillium sp. EPF-6, a fungus isolated from the larvae of mulberry pyralid (Margaronia pyloalis Welker). The molecular formulas of 1, 2 and 3 were determined to be C16H18N2O2, C15H16N2O2 and C16H18N2O3, respectively by FAB-MS and NMR spectral analyses. The structures of these compounds have a novel quinolone skeleton with a gamma-lactam ring consisting of C12H8N2O2 as the common chromophore.

  16. Combining EPR spectroscopy and X-ray crystallography to elucidate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals.

    Science.gov (United States)

    Consentius, Philipp; Gohlke, Ulrich; Loll, Bernhard; Alings, Claudia; Heinemann, Udo; Wahl, Markus C; Risse, Thomas

    2017-08-09

    Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling is used to investigate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals. Within a single crystal, the oriented ensemble of spin bearing moieties results in a strong angle dependence of the EPR spectra. A quantitative description of the EPR spectra requires the determination of the unit cell orientation with respect to the sample tube and the orientation of the spin bearing moieties within the crystal lattice. Angle dependent EPR spectra were analyzed by line shape simulations using the stochastic Liouville equation approach developed by Freed and co-workers and an effective Hamiltonian approach. The gain in spectral information obtained from the EPR spectra of single crystalline samples taken at different frequencies, namely the X-band and Q-band, allows us to discriminate between motional models describing the spectra of isotropic solutions similarly well. In addition, it is shown that the angle dependent single crystal spectra allow us to identify two spin label rotamers with very similar side chain dynamics. These results demonstrate the utility of single crystal EPR spectroscopy in combination with spectral line shape simulation techniques to extract valuable dynamic information not readily available from the analysis of isotropic systems. In addition, it will be shown that the loss of electron density in high resolution diffraction experiments at room temperature does not allow us to conclude that there is significant structural disorder in the system.

  17. Application of Molecular Techniques to Elucidate the Influence of Cellulosic Waste on the Bacterial Community Structure at a Simulated Low-Level-Radioactive-Waste Site

    International Nuclear Information System (INIS)

    Field, Erin K.; D'Imperio, Seth; Miller, Amber R.; VanEngelen, Michael R.; Gerlach, Robin; Lee, Brady D.; Apel, William A.; Peyton, Brent M.

    2010-01-01

    Low-level radioactive waste sites, including those at various U.S. Department of Energy (DOE) sites, frequently contain cellulosic waste in the form of paper towels, cardboard boxes, or wood contaminated with heavy metals and radionuclides such as chromium and uranium. To understand how the soil microbial community is influenced by the presence of cellulosic waste products, multiple soil samples were obtained from a non-radioactive model low-level waste test pit at the Idaho National Laboratory. Samples were analyzed using 16S rDNA clone libraries and 16S rRNA gene microarray (PhyloChip) analyses. Both the clone library and PhyloChip results revealed changes in the bacterial community structure with depth. In all samples, the PhyloChip detected significantly more unique Operational Taxonomic Units (OTUs), and therefore more relative diversity, than the clone libraries. Calculated diversity indices suggest that diversity is lowest in the Fill (F) and Fill Waste (FW) layers and greater in the Wood Waste (WW) and Waste Clay (WC) layers. Principal coordinates analysis and lineage specific analysis determined that Bacteroidetes and Actinobacteria phyla account for most of the significant differences observed between the layers. The decreased diversity in the FW layer and increased members of families containing known cellulose degrading microorganisms suggests the FW layer is an enrichment environment for cellulose degradation. Overall, these results suggest that the presence of the cellulosic material significantly influences the bacterial community structure in a stratified soil system.

  18. Facile synthesis, structure elucidation, and magnetic properties of perovskite BaTb{sub 1-x}Bi{sub x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Farid, Muhammad Asim; Zhang, Hao; Li, Guobao; Liao, Fuhui; Lin, Jianhua [Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing (China); Yang, Aimei [College of Materials Science and Engineering, Guilin University of Technology, 541004, Guilin (China); Tian, Gengfang; Wu, Meimei [Neutron Scattering Laboratory, Department of Nuclear Physics, China Institute of Atomic Energy, 102413, Beijing (China)

    2017-03-17

    A series of perovskite BaTb{sub 1-x}Bi{sub x}O{sub 3} (0.0 ≤ x ≤ 0.25) solid solutions were synthesized by a typical solid-state method. Their structures were analyzed by a combination of X-ray diffraction, neutron diffraction, and selected-area electron diffraction. All of the materials crystalize in the P1 space group [a = 6.0582(1) Aa, b = 6.0473(1) Aa, c = 6.0693(1) Aa, α = 60.00(1) , β = 59.84(1) , γ = 60.06(1) for x = 0.0 at room temperature]. Magnetic measurements revealed that the magnetic-ordering temperature decreases with increasing Bi content in BaTb{sub 1-x}Bi{sub x}O{sub 3}; therefore, the presence of Bi decreases the magnetic interactions of Tb. Furthermore, the magnetic structure for BaTb{sub 1-x}Bi{sub x}O{sub 3} has been fully described in space group P1. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. The effects of thyrotropin-suppressive therapy on bone metabolism in patients with well-differentiated thyroid carcinoma

    NARCIS (Netherlands)

    Heemstra, K. A.; Hamdy, N. A. T.; Romijn, J. A.; Smit, J. W. A.

    2006-01-01

    Patients with differentiated thyroid carcinoma (DTC) are commonly treated long-term with thyrotropin (TSH)- suppressive thyroxine replacement therapy resolving in a state of subclinical hyperthyroidism. The relationship between subclinical hyperthyroidism and osteoporosis is not clear. In this

  20. Using Emergent and Internal Catchment Data to Elucidate the Influence of Landscape Structure and Storage State on Hydrologic Response in a Piedmont Watershed

    Science.gov (United States)

    Putnam, S. M.; Harman, C. J.

    2017-12-01

    Many studies have sought to unravel the influence of landscape structure and catchment state on the quantity and composition of water at the catchment outlet. These studies run into issues of equifinality where multiple conceptualizations of flow pathways or storage states cannot be discriminated against on the basis of the quantity and composition of water alone. Here we aim to parse out the influence of landscape structure, flow pathways, and storage on both the observed catchment hydrograph and chemograph, using hydrometric and water isotope data collected from multiple locations within Pond Branch, a 37-hectare Piedmont catchment of the eastern US. This data is used to infer the quantity and age distribution of water stored and released by individual hydrogeomorphic units, and the catchment as a whole, in order to test hypotheses relating landscape structure, flow pathways, and catchment storage to the hydrograph and chemograph. Initial hypotheses relating internal catchment properties or processes to the hydrograph or chemograph are formed at the catchment scale. Data from Pond Branch include spring and catchment discharge measurements, well water levels, and soil moisture, as well as three years of high frequency precipitation and surface water stable water isotope data. The catchment hydrograph is deconstructed using hydrograph separation and the quantity of water associated with each time-scale of response is compared to the quantity of discharge that could be produced from hillslope and riparian hydrogeomorphic units. Storage is estimated for each hydrogeomorphic unit as well as the vadose zone, in order to construct a continuous time series of total storage, broken down by landscape unit. Rank StorAge Selection (rSAS) functions are parameterized for each hydrogeomorphic unit as well as the catchment as a whole, and the relative importance of changing proportions of discharge from each unit as well as storage in controlling the variability in the catchment

  1. The collaboratory for MS3D: a new cyberinfrastructure for the structural elucidation of biological macromolecules and their assemblies using mass spectrometry-based approaches.

    Science.gov (United States)

    Yu, Eizadora T; Hawkins, Arie; Kuntz, Irwin D; Rahn, Larry A; Rothfuss, Andrew; Sale, Kenneth; Young, Malin M; Yang, Christine L; Pancerella, Carmen M; Fabris, Daniele

    2008-11-01

    Modern biomedical research is evolving with the rapid growth of diverse data types, biophysical characterization methods, computational tools and extensive collaboration among researchers spanning various communities and having complementary backgrounds and expertise. Collaborating researchers are increasingly dependent on shared data and tools made available by other investigators with common interests, thus forming communities that transcend the traditional boundaries of the single research laboratory or institution. Barriers, however, remain to the formation of these virtual communities, usually due to the steep learning curve associated with becoming familiar with new tools, or with the difficulties associated with transferring data between tools. Recognizing the need for shared reference data and analysis tools, we are developing an integrated knowledge environment that supports productive interactions among researchers. Here we report on our current collaborative environment, which focuses on bringing together structural biologists working in the area of mass spectrometric based methods for the analysis of tertiary and quaternary macromolecular structures (MS3D) called the Collaboratory for MS3D (C-MS3D). C-MS3D is a Web-portal designed to provide collaborators with a shared work environment that integrates data storage and management with data analysis tools. Files are stored and archived along with pertinent meta data in such a way as to allow file handling to be tracked (data provenance) and data files to be searched using keywords and modification dates. While at this time the portal is designed around a specific application, the shared work environment is a general approach to building collaborative work groups. The goal of this is to not only provide a common data sharing and archiving system, but also to assist in the building of new collaborations and to spur the development of new tools and technologies.

  2. Elucidation of electronic structure by the analysis of hyperfine interactions: The MnH A 7Π-X 7Sigma + (0,0) band

    Science.gov (United States)

    Varberg, Thomas D.; Field, Robert W.; Merer, Anthony J.

    1991-08-01

    We present a complete analysis of the hyperfine structure of the MnH A 7Π-X 7Σ+ (0,0) band near 5680 Å, studied with sub-Doppler resolution by intermodulated fluorescence spectroscopy. Magnetic hyperfine interactions involving both the 55Mn (I=5/2) and 1H (I=1/2) nuclear spins are observed as well as 55Mn electric quadrupole effects. The manganese Fermi contact interaction in the X 7Σ+ state is the dominant contributor to the observed hyperfine splittings; the ΔF=0, ΔN=0, ΔJ=±1 matrix elements of this interaction mix the electron spin components of the ground state quite strongly at low N, destroying the ``goodness'' of J as a quantum number and inducing rotationally forbidden, ΔJ=±2 and ±3 transitions. The hyperfine splittings of over 50 rotational transitions covering all 7 spin components of both states were analyzed and fitted by least squares, allowing the accurate determination of 14 different hyperfine parameters. Using single electronic configurations to describe the A 7Π and X 7Σ+ states and Herman-Skillman atomic radial wave functions to represent the molecular orbitals, we calculated a priori values for the 55Mn and 1H hyperfine parameters which agree closely with experiment. We show that the five high-spin coupled Mn 3d electrons do not contribute to the manganese hyperfine structure but are responsible for the observed proton magnetic dipolar couplings. Furthermore, the results suggest that the Mn 3d electrons are not significantly involved in bonding and demonstrate that the molecular hyperfine interactions may be quantitatively understood using simple physical interpretations.

  3. Dual Inhibition of AChE and BChE with the C-5 Substituted Derivative of Meldrum’s Acid: Synthesis, Structure Elucidation, and Molecular Docking Studies

    Directory of Open Access Journals (Sweden)

    Haroon Mehfooz

    2017-07-01

    Full Text Available Alzheimer’s disease (AD lies in the category of those diseases which are still posing challenges to medicinal chemists, and the search for super-effective drugs for the treatment of AD is a work in progress. The inhibition of cholinesterase is considered a viable strategy to enhance the level of acetylcholine in the brain. The C-5 substituted derivative of Meldrum’s acid was synthesized and screened against acetylcholinesterase (AChE and butyrylcholinesterase (BChE enzyme inhibition activity. The simple and unique structure of synthesized derivative 3 was found to be good for the dual inhibition of both enzymes (AChE and BChE. 2,2-Dimethyl-5-(([2-(trifluoromethyl phenyl]aminomethylidene-1,3-dioxane-4,6-dione (3 showed significant inhibition against AChE, with an IC50 value of 1.13 ± 0.03 µ M (Standard Neostigmine 22.2 ± 3.2 µM, and moderate inhibition against BChE, with an IC50 value of 2.12 ± 1.22 µM (Standard Neostigmine 49.6 ± 6.11 µM. The structural insights reveal that compound 3 possesses intriguing reactive groups, which can potentially evoke the non-covalent interactions and possibly assist by binding in the active site of the target protein. Docking simulations revealed that the compound 3 showed binding inside the active site gorges of both AChE and BChE. An excellent agreement was obtained, as the best docked poses showed important binding features mostly based on interactions due to oxygen atoms and the aromatic moieties of the compound. The docking computations coupled with the experimental findings ascertained that the compound 3 can serve as a scaffold for the dual inhibitors of the human acetylcholine esterases.

  4. Synthesis, Structure Elucidation, and Redox Properties of (superscript 99)Tc Complexes of Lacunary Wells-Dawson Polyoxometalates: Insights into Molecular (superscript 99)Tc-Metal Oxide Interactions

    International Nuclear Information System (INIS)

    McGregor, Donna; Burton-Pye, Benjamin P.; Howell, Robertha C.; Mbomekalle, Israel M.; Lukens, Wayne W. Jr.; Bian, Fang; Mausolf, Edward; Poineau, Frederic; Czerwinski, Kenneth R.; Francesconi, Lynn C.

    2011-01-01

    The isotope 99 Tc (β max , 293.7; half-life, 2.1 x 10 5 years) is an abundant product of uranium-235 fission in nuclear reactors and is present throughout the radioactive waste stored in underground tanks at the Hanford and Savannah River sites. Understanding and controlling the extensive redox chemistry of 99 Tc is important in identifying tunable strategies to separate 99 Tc from spent fuel and from waste tanks and, once separated, to identify and develop an appropriately stable waste form for 99 Tc. Polyoxometalates (POMs), nanometer-sized models for metal oxide solid-state materials, are used in this study to provide a molecular level understanding of the speciation and redox chemistry of incorporated 99 Tc. In this study, 99 Tc complexes of the (α 2 -P 2 W 17 O 61 ) 10- and (α 1 -P 2 W 17 O 61 ) 10- isomers were prepared. Ethylene glycol was used as a 'transfer ligand' to minimize the formation of TcO 2 · xH 2 O. The solution structures, formulations, and purity of TcVO(α 1 /α 2 -P 2 W 17 O 61 ) 7- were determined by multinuclear NMR. X-ray absorption spectroscopy of the complexes is in agreement with the formulation and structures determined from 31 P and 183 W NMR. Preliminary electrochemistry results are consistent with the EXAFS results, showing a facile reduction of the TcVO(α 1 -P 2 W 17 O 61 ) 7- species compared to the TcVO(α 2 -P 2 W 17 O 61 ) 7- analog. The α 1 defect is unique in that a basic oxygen atom is positioned toward the α 1 site, and the Tc V O center appears to form a dative metal-metal bond with a framework W site. These attributes may lead to the assistance of protonation events that facilitate reduction. Electrochemistry comparison shows that the ReV analogs are about 200 mV more difficult to reduce in accordance with periodic trends.

  5. Synthesis, structure elucidation and redox properties of 99Tc complexes of lacunary Wells Dawson polyoxometalates: insights into molecular 99Tc - metal oxide interactions

    International Nuclear Information System (INIS)

    McGregor, Donna; Burton-Pye, Benjamin P.; Howell, Robertha C.; Mbomekalle, Israel M.; Lukens, Wayne W. Jr; Bian, Fang; Mausolf, Edward; Poineau, Frederic; Czerwinski, Kenneth R; Francesconi, Lynn C.

    2011-01-01

    The isotope 99 Tc (β max : 250 keV, half-life: 2 x 10 5 year) is an abundant product of uranium-235 fission in nuclear reactors and is present throughout the radioactive waste stored in underground tanks at Hanford and Savannah River. Understanding and controlling the extensive redox chemistry of 99 Tc is important to identify tunable strategies to separate 99 Tc from spent fuel and from waste tanks and once separated, to identify and develop an appropriately stable waste-form for 99 Tc. Polyoxometalates (POMs), nanometer sized models for metal oxide solid-state materials, are used in this study to provide a molecular level understanding of the speciation and redox chemistry of incorporated 99 Tc. In this study, 99 Tc complexes of the (α 2 -P 2 W 17 O 61 ) 10- and (α 1 -P 2 W 17 O 61 ) 10- isomers were prepared. Ethylene glycol was used as a 'transfer ligand' to minimize the formation of TcO 2 · xH 2 O. The solution structures, formulations, and purity of Tc V O(α 1 /α 2 -P 2 W 17 O 61 ) 7- were determined by multinuclear NMR. X-ray Absorption Spectroscopy of the complexes are in agreement with the formulation and structures determined from 31 P and 183 W NMR. Preliminary electrochemistry results are consistent with the EXAFS results, showing a facile reduction of the Tc V O(α 1 -P 2 W 17 O 61 ) 7- species compared to the Tc V O(α 2 -P 2 W 17 O 61 ) 7- analog. The α 1 -defect is unique in that a basic oxygen atom is positioned toward the α 1 -site and the Tc V O center appears to form a dative metal-metal bond with a framework W site. These attributes may lead to the assistance of protonation events that facilitate reduction. Electrochemistry comparison shows that the Re V analogs are about 200 mV more difficult to reduce in accordance with periodic trends.

  6. An exceptionally potent inducer of cytoprotective enzymes: elucidation of the structural features that determine inducer potency and reactivity with Keap1.

    Science.gov (United States)

    Dinkova-Kostova, Albena T; Talalay, Paul; Sharkey, John; Zhang, Ying; Holtzclaw, W David; Wang, Xiu Jun; David, Emilie; Schiavoni, Katherine H; Finlayson, Stewart; Mierke, Dale F; Honda, Tadashi

    2010-10-29

    The Keap1/Nrf2/ARE pathway controls a network of cytoprotective genes that defend against the damaging effects of oxidative and electrophilic stress, and inflammation. Induction of this pathway is a highly effective strategy in combating the risk of cancer and chronic degenerative diseases, including atherosclerosis and neurodegeneration. An acetylenic tricyclic bis(cyano enone) bearing two highly electrophilic Michael acceptors is an extremely potent inducer in cells and in vivo. We demonstrate spectroscopically that both cyano enone functions of the tricyclic molecule react with cysteine residues of Keap1 and activate transcription of cytoprotective genes. Novel monocyclic cyano enones, representing fragments of rings A and C of the tricyclic compound, reveal that the contribution to inducer potency of the ring C Michael acceptor is much greater than that of ring A, and that potency is further enhanced by spatial proximity of an acetylenic function. Critically, the simultaneous presence of two cyano enone functions in rings A and C within a rigid three-ring system results in exceptionally high inducer potency. Detailed understanding of the structural elements that contribute to the reactivity with the protein sensor Keap1 and to high potency of induction is essential for the development of specific and selective lead compounds as clinically relevant chemoprotective agents.

  7. Structure of lipid kinase p110β/p85β elucidates an unusual SH2-domain-mediated inhibitory mechanism.

    Science.gov (United States)

    Zhang, Xuxiao; Vadas, Oscar; Perisic, Olga; Anderson, Karen E; Clark, Jonathan; Hawkins, Phillip T; Stephens, Len R; Williams, Roger L

    2011-03-04

    Phosphoinositide 3-kinases (PI3Ks) are essential for cell growth, migration, and survival. The structure of a p110β/p85β complex identifies an inhibitory function for the C-terminal SH2 domain (cSH2) of the p85 regulatory subunit. Mutagenesis of a cSH2 contact residue activates downstream signaling in cells. This inhibitory contact ties up the C-terminal region of the p110β catalytic subunit, which is essential for lipid kinase activity. In vitro, p110β basal activity is tightly restrained by contacts with three p85 domains: the cSH2, nSH2, and iSH2. RTK phosphopeptides relieve inhibition by nSH2 and cSH2 using completely different mechanisms. The binding site for the RTK's pYXXM motif is exposed on the cSH2, requiring an extended RTK motif to reach and disrupt the inhibitory contact with p110β. This contrasts with the nSH2 where the pY-binding site itself forms the inhibitory contact. This establishes an unusual mechanism by which p85 SH2 domains contribute to RTK signaling specificities. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Crystallographic analysis of human hemoglobin elucidates the structural basis of the potent and dual antisickling activity of pyridyl derivatives of vanillin

    Energy Technology Data Exchange (ETDEWEB)

    Abdulmalik, Osheiza [The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); Ghatge, Mohini S.; Musayev, Faik N.; Parikh, Apurvasena [Virginia Commonwealth University, Richmond, VA 23298 (United States); Chen, Qiukan; Yang, Jisheng [The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); Nnamani, Ijeoma [Duke University Medical Center, Durham, NC 27710 (United States); Danso-Danquah, Richmond [Virginia Commonwealth University, Richmond, VA 23298 (United States); Eseonu, Dorothy N. [Virginia Union University, Richmond, VA 23220 (United States); Asakura, Toshio [Duke University Medical Center, Durham, NC 27710 (United States); Abraham, Donald J.; Venitz, Jurgen; Safo, Martin K., E-mail: msafo@vcu.edu [Virginia Commonwealth University, Richmond, VA 23298 (United States); The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States)

    2011-11-01

    Pyridyl derivatives of vanillin increase the fraction of the more soluble oxygenated sickle hemoglobin and/or directly increase the solubility of deoxygenated sickle hemoglobin. Crystallographic analysis reveals the structural basis of the potent and dual antisickling activity of these derivatives. Vanillin has previously been studied clinically as an antisickling agent to treat sickle-cell disease. In vitro investigations with pyridyl derivatives of vanillin, including INN-312 and INN-298, showed as much as a 90-fold increase in antisickling activity compared with vanillin. The compounds preferentially bind to and modify sickle hemoglobin (Hb S) to increase the affinity of Hb for oxygen. INN-312 also led to a considerable increase in the solubility of deoxygenated Hb S under completely deoxygenated conditions. Crystallographic studies of normal human Hb with INN-312 and INN-298 showed that the compounds form Schiff-base adducts with the N-terminus of the α-subunits to constrain the liganded (or relaxed-state) Hb conformation relative to the unliganded (or tense-state) Hb conformation. Interestingly, while INN-298 binds and directs its meta-positioned pyridine-methoxy moiety (relative to the aldehyde moiety) further down the central water cavity of the protein, that of INN-312, which is ortho to the aldehyde, extends towards the surface of the protein. These studies suggest that these compounds may act to prevent sickling of SS cells by increasing the fraction of the soluble high-affinity Hb S and/or by stereospecific inhibition of deoxygenated Hb S polymerization.

  9. Crystallographic analysis of human hemoglobin elucidates the structural basis of the potent and dual antisickling activity of pyridyl derivatives of vanillin

    International Nuclear Information System (INIS)

    Abdulmalik, Osheiza; Ghatge, Mohini S.; Musayev, Faik N.; Parikh, Apurvasena; Chen, Qiukan; Yang, Jisheng; Nnamani, Ijeoma; Danso-Danquah, Richmond; Eseonu, Dorothy N.; Asakura, Toshio; Abraham, Donald J.; Venitz, Jurgen; Safo, Martin K.

    2011-01-01

    Pyridyl derivatives of vanillin increase the fraction of the more soluble oxygenated sickle hemoglobin and/or directly increase the solubility of deoxygenated sickle hemoglobin. Crystallographic analysis reveals the structural basis of the potent and dual antisickling activity of these derivatives. Vanillin has previously been studied clinically as an antisickling agent to treat sickle-cell disease. In vitro investigations with pyridyl derivatives of vanillin, including INN-312 and INN-298, showed as much as a 90-fold increase in antisickling activity compared with vanillin. The compounds preferentially bind to and modify sickle hemoglobin (Hb S) to increase the affinity of Hb for oxygen. INN-312 also led to a considerable increase in the solubility of deoxygenated Hb S under completely deoxygenated conditions. Crystallographic studies of normal human Hb with INN-312 and INN-298 showed that the compounds form Schiff-base adducts with the N-terminus of the α-subunits to constrain the liganded (or relaxed-state) Hb conformation relative to the unliganded (or tense-state) Hb conformation. Interestingly, while INN-298 binds and directs its meta-positioned pyridine-methoxy moiety (relative to the aldehyde moiety) further down the central water cavity of the protein, that of INN-312, which is ortho to the aldehyde, extends towards the surface of the protein. These studies suggest that these compounds may act to prevent sickling of SS cells by increasing the fraction of the soluble high-affinity Hb S and/or by stereospecific inhibition of deoxygenated Hb S polymerization

  10. Three-dimensional quantitative structure-activity relationship (3D QSAR) and pharmacophore elucidation of tetrahydropyran derivatives as serotonin and norepinephrine transporter inhibitors

    Science.gov (United States)

    Kharkar, Prashant S.; Reith, Maarten E. A.; Dutta, Aloke K.

    2008-01-01

    Three-dimensional quantitative structure-activity relationship (3D QSAR) using comparative molecular field analysis (CoMFA) was performed on a series of substituted tetrahydropyran (THP) derivatives possessing serotonin (SERT) and norepinephrine (NET) transporter inhibitory activities. The study aimed to rationalize the potency of these inhibitors for SERT and NET as well as the observed selectivity differences for NET over SERT. The dataset consisted of 29 molecules, of which 23 molecules were used as the training set for deriving CoMFA models for SERT and NET uptake inhibitory activities. Superimpositions were performed using atom-based fitting and 3-point pharmacophore-based alignment. Two charge calculation methods, Gasteiger-Hückel and semiempirical PM3, were tried. Both alignment methods were analyzed in terms of their predictive abilities and produced comparable results with high internal and external predictivities. The models obtained using the 3-point pharmacophore-based alignment outperformed the models with atom-based fitting in terms of relevant statistics and interpretability of the generated contour maps. Steric fields dominated electrostatic fields in terms of contribution. The selectivity analysis (NET over SERT), though yielded models with good internal predictivity, showed very poor external test set predictions. The analysis was repeated with 24 molecules after systematically excluding so-called outliers (5 out of 29) from the model derivation process. The resulting CoMFA model using the atom-based fitting exhibited good statistics and was able to explain most of the selectivity (NET over SERT)-discriminating factors. The presence of -OH substituent on the THP ring was found to be one of the most important factors governing the NET selectivity over SERT. Thus, a 4-point NET-selective pharmacophore, after introducing this newly found H-bond donor/acceptor feature in addition to the initial 3-point pharmacophore, was proposed.

  11. Elucidating the structural properties that influence the persistence of PCBs in humans using the National Health and Nutrition Examination Survey (NHANES) dataset

    Energy Technology Data Exchange (ETDEWEB)

    Megson, David, E-mail: dpmegson@hotmail.co.uk [Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA (United Kingdom); O’Sullivan, Gwen [Department of Environmental Science, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, Alberta, T3E 6K6 (Canada); Comber, Sean; Worsfold, Paul J.; Lohan, Maeve C. [Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA (United Kingdom); Edwards, Melanie R.; Shields, Walter J. [Exponent Inc., 15375 Southeast 30th Place, Bellevue, WA 98007 (United States); Sandau, Courtney D. [Chemistry Matters Inc., 2120 1st Avenue NW, Calgary, Alberta T2N 0B5 (Canada); Patterson, Donald G. [Exponent Inc., One Capital City Plaza, Suite 1620, 3350 Peachtree Road, Atlanta, GA 30326 (United States)

    2013-09-01

    In human exposure studies involving Polychlorinated Biphenyls (PCBs), it is useful to establish when an individual was potentially exposed. Age dating PCB exposure is complex but assessments can be made because different PCB congeners have different residence times in the human body. The less chlorinated congeners generally tend to have shorter residence times because they are biotransformed and eliminated faster than more chlorinated congeners. Therefore, the presence of high proportions of less chlorinated congeners is often indicative of recent exposure. The 2003–04 National Health and Nutrition Examination Survey (NHANES) dataset contains results for the concentration of 37 PCBs in a sub-sample of the US population. Multivariate statistical analysis of the NHANES data showed that less chlorinated congeners are not always biotransformed faster than higher chlorinated compounds. For example, PCB 28 (a tri-chlorobiphenyl) appears to be more resistant to biotransformation than PCB 101 and 110 (penta-chlorobiphenyls). Using statistical analysis of the NHANES data in conjunction with previously published studies on PCB persistence in humans, it was possible to identify the structural relationships that determine if a PCB is likely to be from a recent exposure (termed ‘episodic’) or from steady state exposure. Congeners with chlorine atoms in the 2,5- and 2,3,6-positions appear to be more susceptible to biotransformation whereas congeners with chlorine bonds in the 2,3,4- 2,4,5- 3,4,5- and 2,3,4,5-positions appear to be more persistent. This work shows that future investigations to date PCB exposure would benefit from the analysis of a wide range of congeners, including the selection of key congeners based not only on the degree of chlorination but also on the positions of the chlorine atoms on the biphenyl. - Highlights: • NHANES data was used to compare the PCB signature of different aged participants. • PCB residence time may be explained by the number

  12. Elucidating the structural properties that influence the persistence of PCBs in humans using the National Health and Nutrition Examination Survey (NHANES) dataset

    International Nuclear Information System (INIS)

    Megson, David; O’Sullivan, Gwen; Comber, Sean; Worsfold, Paul J.; Lohan, Maeve C.; Edwards, Melanie R.; Shields, Walter J.; Sandau, Courtney D.; Patterson, Donald G.

    2013-01-01

    In human exposure studies involving Polychlorinated Biphenyls (PCBs), it is useful to establish when an individual was potentially exposed. Age dating PCB exposure is complex but assessments can be made because different PCB congeners have different residence times in the human body. The less chlorinated congeners generally tend to have shorter residence times because they are biotransformed and eliminated faster than more chlorinated congeners. Therefore, the presence of high proportions of less chlorinated congeners is often indicative of recent exposure. The 2003–04 National Health and Nutrition Examination Survey (NHANES) dataset contains results for the concentration of 37 PCBs in a sub-sample of the US population. Multivariate statistical analysis of the NHANES data showed that less chlorinated congeners are not always biotransformed faster than higher chlorinated compounds. For example, PCB 28 (a tri-chlorobiphenyl) appears to be more resistant to biotransformation than PCB 101 and 110 (penta-chlorobiphenyls). Using statistical analysis of the NHANES data in conjunction with previously published studies on PCB persistence in humans, it was possible to identify the structural relationships that determine if a PCB is likely to be from a recent exposure (termed ‘episodic’) or from steady state exposure. Congeners with chlorine atoms in the 2,5- and 2,3,6-positions appear to be more susceptible to biotransformation whereas congeners with chlorine bonds in the 2,3,4- 2,4,5- 3,4,5- and 2,3,4,5-positions appear to be more persistent. This work shows that future investigations to date PCB exposure would benefit from the analysis of a wide range of congeners, including the selection of key congeners based not only on the degree of chlorination but also on the positions of the chlorine atoms on the biphenyl. - Highlights: • NHANES data was used to compare the PCB signature of different aged participants. • PCB residence time may be explained by the number

  13. Structure Elucidation of New Acetylated Saponins, Lessoniosides A, B, C, D, and E, and Non-Acetylated Saponins, Lessoniosides F and G, from the Viscera of the Sea Cucumber Holothuria lessoni

    Directory of Open Access Journals (Sweden)

    Yadollah Bahrami

    2015-01-01

    Full Text Available Sea cucumbers produce numerous compounds with a wide range of chemical structural diversity. Among these, saponins are the most diverse and include sulfated, non-sulfated, acetylated and methylated congeners with different aglycone and sugar moieties. In this study, MALDI and ESI tandem mass spectrometry, in the positive ion mode, were used to elucidate the structure of new saponins extracted from the viscera of H. lessoni. Fragmentation of the aglycone provided structural information on the presence of the acetyl group. The presence of the O-acetyl group was confirmed by observing the mass transition of 60 u corresponding to the loss of a molecule of acetic acid. Ion fingerprints from the glycosidic cleavage provided information on the mass of the aglycone (core, and the sequence and type of monosaccharides that constitute the sugar moiety. The tandem mass spectra of the saponin precursor ions [M + Na]+ provided a wealth of detailed structural information on the glycosidic bond cleavages. As a result, and in conjunction with existing literature, we characterized the structure of five new acetylated saponins, Lessoniosides A–E, along with two non-acetylated saponins Lessoniosides F and G at m/z 1477.7, which are promising candidates for future drug development. The presented strategy allows a rapid, reliable and complete analysis of native saponins.

  14. Structure Elucidation of New Acetylated Saponins, Lessoniosides A, B, C, D, and E, and Non-Acetylated Saponins, Lessoniosides F and G, from the Viscera of the Sea Cucumber Holothuria lessoni

    Science.gov (United States)

    Bahrami, Yadollah; Franco, Christopher M. M.

    2015-01-01

    Sea cucumbers produce numerous compounds with a wide range of chemical structural diversity. Among these, saponins are the most diverse and include sulfated, non-sulfated, acetylated and methylated congeners with different aglycone and sugar moieties. In this study, MALDI and ESI tandem mass spectrometry, in the positive ion mode, were used to elucidate the structure of new saponins extracted from the viscera of H. lessoni. Fragmentation of the aglycone provided structural information on the presence of the acetyl group. The presence of the O-acetyl group was confirmed by observing the mass transition of 60 u corresponding to the loss of a molecule of acetic acid. Ion fingerprints from the glycosidic cleavage provided information on the mass of the aglycone (core), and the sequence and type of monosaccharides that constitute the sugar moiety. The tandem mass spectra of the saponin precursor ions [M + Na]+ provided a wealth of detailed structural information on the glycosidic bond cleavages. As a result, and in conjunction with existing literature, we characterized the structure of five new acetylated saponins, Lessoniosides A–E, along with two non-acetylated saponins Lessoniosides F and G at m/z 1477.7, which are promising candidates for future drug development. The presented strategy allows a rapid, reliable and complete analysis of native saponins. PMID:25603350

  15. Principles and determinants of G-protein coupling by the rhodopsin-like thyrotropin receptor.

    Directory of Open Access Journals (Sweden)

    Gunnar Kleinau

    Full Text Available In this study we wanted to gain insights into selectivity mechanisms between G-protein-coupled receptors (GPCR and different subtypes of G-proteins. The thyrotropin receptor (TSHR binds G-proteins promiscuously and activates both Gs (cAMP and Gq (IP. Our goal was to dissect selectivity patterns for both pathways in the intracellular region of this receptor. We were particularly interested in the participation of poorly investigated receptor parts.We systematically investigated the amino acids of intracellular loop (ICL 1 and helix 8 using site-directed mutagenesis alongside characterization of cAMP and IP accumulation. This approach was guided by a homology model of activated TSHR in complex with heterotrimeric Gq, using the X-ray structure of opsin with a bound G-protein peptide as a structural template.We provide evidence that ICL1 is significantly involved in G-protein activation and our model suggests potential interactions with subunits G alpha as well as G betagamma. Several amino acid substitutions impaired both IP and cAMP accumulation. Moreover, we found a few residues in ICL1 (L440, T441, H443 and helix 8 (R687 that are sensitive for Gq but not for Gs activation. Conversely, not even one residue was found that selectively affects cAMP accumulation only. Together with our previous mutagenesis data on ICL2 and ICL3 we provide here the first systematically completed map of potential interfaces between TSHR and heterotrimeric G-protein. The TSHR/Gq-heterotrimer complex is characterized by more selective interactions than the TSHR/Gs complex. In fact the receptor interface for binding Gs is a subset of that for Gq and we postulate that this may be true for other GPCRs coupling these G-proteins. Our findings support that G-protein coupling and preference is dominated by specific structural features at the intracellular region of the activated GPCR but is completed by additional complementary recognition patterns between receptor and G

  16. Principles and determinants of G-protein coupling by the rhodopsin-like thyrotropin receptor.

    Science.gov (United States)

    Kleinau, Gunnar; Jaeschke, Holger; Worth, Catherine L; Mueller, Sandra; Gonzalez, Jorge; Paschke, Ralf; Krause, Gerd

    2010-03-18

    In this study we wanted to gain insights into selectivity mechanisms between G-protein-coupled receptors (GPCR) and different subtypes of G-proteins. The thyrotropin receptor (TSHR) binds G-proteins promiscuously and activates both Gs (cAMP) and Gq (IP). Our goal was to dissect selectivity patterns for both pathways in the intracellular region of this receptor. We were particularly interested in the participation of poorly investigated receptor parts.We systematically investigated the amino acids of intracellular loop (ICL) 1 and helix 8 using site-directed mutagenesis alongside characterization of cAMP and IP accumulation. This approach was guided by a homology model of activated TSHR in complex with heterotrimeric Gq, using the X-ray structure of opsin with a bound G-protein peptide as a structural template.We provide evidence that ICL1 is significantly involved in G-protein activation and our model suggests potential interactions with subunits G alpha as well as G betagamma. Several amino acid substitutions impaired both IP and cAMP accumulation. Moreover, we found a few residues in ICL1 (L440, T441, H443) and helix 8 (R687) that are sensitive for Gq but not for Gs activation. Conversely, not even one residue was found that selectively affects cAMP accumulation only. Together with our previous mutagenesis data on ICL2 and ICL3 we provide here the first systematically completed map of potential interfaces between TSHR and heterotrimeric G-protein. The TSHR/Gq-heterotrimer complex is characterized by more selective interactions than the TSHR/Gs complex. In fact the receptor interface for binding Gs is a subset of that for Gq and we postulate that this may be true for other GPCRs coupling these G-proteins. Our findings support that G-protein coupling and preference is dominated by specific structural features at the intracellular region of the activated GPCR but is completed by additional complementary recognition patterns between receptor and G-protein subtypes.

  17. High-pressure synthesis and single-crystal structure elucidation of the indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Ortner, Teresa S.; Vitzthum, Daniela; Heymann, Gunter; Huppertz, Hubert [Department of General, Inorganic and Theoretical Chemistry, Centre of Chemistry and Biomedicine (CCB), Leopold-Franzens-University Innsbruck (Austria)

    2017-12-29

    The indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7} was synthesized under high-pressure/high-temperature conditions at 12.5 GPa/1420 K using a Walker-type multianvil apparatus. Single-crystal X-ray structure elucidation showed edge-sharing OIn{sub 4} tetrahedra and B{sub 2}O{sub 7} units building up the oxide-borate. It crystallizes with Z = 8 in the monoclinic space group P2{sub 1}/n (no. 14) with a = 1016.54(3), b = 964.55(3), c = 1382.66(4) pm, and β = 109.7(1) . The compound was also characterized by powder X-ray diffraction and vibrational spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Radioimmunoassay of Human Thyrotropin - Part 1. Plasma TSH levels in various thyroid functions

    International Nuclear Information System (INIS)

    Koh, Chang Soon; Lee, Hong Kyu; Ro, Heung Kyu; Lee, Mun Ho

    1972-01-01

    The radioimmunoassay of human thyrotropin was performed in various thyroid states, utilizing the anti-h-T.S.H. antibody and purified human thyrotropin supplied from National Institute of Arthritis and Metabolic Diseases, Bethesda, Ma., U.S.A., and human thyrotropin standard-A obtained from National Institute for Biologic Standards, Mill Hill, London, England. 131 I labelled h-TSH was prepared after the Chloramine-T method of Greenwood et al. This double antibody system had a assay sensitivity of about l. 0 μU/ml of plasma HTS-A and could detect the plasma h-TSH level in the euthyroid patients. Plasma h-TSH level of the normal 26 Korean was l.1±0. 83 μU/ml, and that of the 8 hypothyroidisms were 8.3 to 67.5 μU/ml. In hyperthyroidisms, no cases showed the plasma h-TSH levels over l. 0 μU/ ml. Between the hypothyroidism and euthyroidism, no overlap is noticed on plasma h-TSH levels. A case of transient hypothyroid state identified by determination of plasma h-TSH level is presented. These results revealed that the radioimmunoassay of h-TSH in plasma could be a sensitive method to diagnose the hypothyroidism, if not caused by a pituitary disease.

  19. Examination of some factors affecting sensitivity and reproducibility in radioimmunoassay of thyrotropin

    International Nuclear Information System (INIS)

    Moser, R.J.; Hollingsworth, D.R.

    1975-01-01

    Conditions for measuring human thyrotropin by radioimmunoassay have been investigated, to improve the sensitivity and reproducibility of the assay. The Chloramine-T method of iodination was used, the reaction time being 20 s. Doubling the iodination reaction volume from 55 to 95 μl did not affect the immunoreactivity. Purification of labeled hormone by use of anion-exchange resin followed by silica (Quso G-32) instead of Sephadex gel-filtration or anion exchange alone yielded a product that was the least (less than 4 percent) contaminated with Na 125 I. Human serum albumin (2.5 g/liter)in phosphate-buffered saline, instead of bovine serum, should be used as diluent for unknowns; within-assay variance was 3 percent for the former, 62 percent for the latter. The assay worked equally well for both pregnant and nonpregnant patients, with use of 50 to 100 μl of serum per determination. A five-week-old labeled hormone yielded higher values than did two-week-old material. In 29 euthyroid patients the mean thyrotropin value was 5.7 microunits/ml (range 2.8 to 11); nine hypothyroid patients had a mean of 112 microunits/ml (range 38 to 267); and 13 hyperthyroid subjects showed suppressed thyrotropin with a mean of 3.1 microunits/ml (range 2.2 to 4.5). Following these suggestions, one can expect a highly purified immunoreactive tracer and a sensitive assay. (U.S.)

  20. Intrauterine Zn Deficiency Favors Thyrotropin-Releasing Hormone-Increasing Effects on Thyrotropin Serum Levels and Induces Subclinical Hypothyroidism in Weaned Rats

    Directory of Open Access Journals (Sweden)

    Viridiana Alcántara-Alonso

    2017-10-01

    Full Text Available Individuals who consume a diet deficient in zinc (Zn-deficient develop alterations in hypothalamic-pituitary-thyroid axis function, i.e., a low metabolic rate and cold insensitivity. Although those disturbances are related to primary hypothyroidism, intrauterine or postnatal Zn-deficient adults have an increased thyrotropin (TSH concentration, but unchanged thyroid hormone (TH levels and decreased body weight. This does not support the view that the hypothyroidism develops due to a low Zn intake. In addition, intrauterine or postnatal Zn-deficiency in weaned and adult rats reduces the activity of pyroglutamyl aminopeptidase II (PPII in the medial-basal hypothalamus (MBH. PPII is an enzyme that degrades thyrotropin-releasing hormone (TRH. This hypothalamic peptide stimulates its receptor in adenohypophysis, thereby increasing TSH release. We analyzed whether earlier low TH is responsible for the high TSH levels reported in adults, or if TRH release is enhanced by Zn deficiency at weaning. Dams were fed a 2 ppm Zn-deficient diet in the period from one week prior to gestation and up to three weeks after delivery. We found a high release of hypothalamic TRH, which along with reduced MBH PPII activity, increased TSH levels in Zn-deficient pups independently of changes in TH concentration. We found that primary hypothyroidism did not develop in intrauterine Zn-deficient weaned rats and we confirmed that metal deficiency enhances TSH levels since early-life, favoring subclinical hypothyroidism development which remains into adulthood.

  1. Ultrahigh-performance liquid chromatography-ion trap mass spectrometry characterization of the steroidal saponins of Dioscorea panthaica Prain et Burkill and its application for accelerating the isolation and structural elucidation of steroidal saponins.

    Science.gov (United States)

    Wang, Weihao; Zhao, Ye; Jing, Wenguang; Zhang, Jun; Xiao, Hui; Zha, Qin; Liu, An

    2015-03-01

    Dioscorea panthaica is a traditional Chinese medicinal herb used in the treatment of various physiological conditions, including cardiovascular disease, gastropathy and hypertension. Steroidal saponins (SS) are the main active ingredients of this herb and have effects on myocardial ischemia and cancer. The phytochemical evaluation of SS is both time-consuming and laborious, and the isolation and structural determination steps can be especially demanding. For this reason, the development of new methods to accelerate the processes involved in the identification, isolation and structural elucidation of SS is highly desirable. In this study, a new ultrahigh performance liquid chromatography-ion trap mass spectrometry (UHPLC-IT/MS(n)) method has been developed for the identification of the SS in D. panthaica Prain et Burkill. Notably, the current method can distinguish between spirostanol and furostanol-type compounds based on the fragmentation patterns observed by electrospray ionization-ion trap mass spectrometry (ESI-IT/MS(n)) analysis. UHPLC-IT/MS(n) was used to conduct a detailed investigation of the number, structural class and order of the sugar moieties in the sugar chains of the SS present in D. panthaica. The established fragmentation features were used to analyze the compounds found in the 65% ethanol fraction of the water extracts of D. panthaica. Twenty-three SS were identified, including 11 potential new compounds and six groups of isomers. Two of these newly identified SS were selected as representative examples, and their chemical structures were confirmed by (1)H and (13)C NMR analyses. This newly developed UHPLC-IT/MS(n) method therefore allowed for the efficient identification, isolation and structural determination of the SS in D. panthaica. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Structure elucidation of the diagnostic product ion at m/z 97 derived from androst-4-en-3-one-based steroids by ESI-CID and IRMPD spectroscopy.

    Science.gov (United States)

    Thevis, Mario; Beuck, Simon; Höppner, Sebastian; Thomas, Andreas; Held, Joseph; Schäfer, Mathias; Oomens, Jos; Schänzer, Wilhelm

    2012-03-01

    Structure elucidation of steroids by mass spectrometry has been of great importance to various analytical arenas and numerous studies were conducted to provide evidence for the composition and origin of (tandem) mass spectrometry-derived product ions used to characterize and identify steroidal substances. The common product ion at m/z 97 generated from androst-4-ene-3-one analogs has been subject of various studies, including stable isotope-labeling and (high resolution/high accuracy) tandem mass spectrometry, but its gas-phase structure has never been confirmed. Using high resolution/high accuracy mass spectrometry and low resolution tandem mass spectrometry, density functional theory (DFT) calculation, and infrared multiple photon dissociation (IRMPD) spectroscopy employing a free electron laser, the structure of m/z 97 derived from testosterone was assigned to protonated 3-methyl-2-cyclopenten-1-one. This ion was identified in a set of six cyclic C(6)H(9)O(+) isomers as computed at the B3LYP/6-311++G(2d,2p) level of theory (protonated 3-methyl-2-cyclopenten-1-one, 2-methyl-2-cyclopenten-1-one and 2-cyclohexen-1-one). Product ions of m/z 97 obtained from MS(2) and MS(3) experiments of protonated 3-methyl-2-cyclopenten-1-one, 2-methyl-2-cyclopenten-1-one, 2-cyclohexen-1-one, and testosterone corroborated the suggested gas-phase ion structure, which was eventually substantiated by IRMPD spectroscopy yielding a spectrum that convincingly matched the predicted counterpart. Finally, the dissociation pathway of the protonated molecule of testosterone to m/z 97 was revisited and an alternative pathway was suggested that considers the exclusion of C-10 along with the inclusion of C-5, which was experimentally demonstrated with stable isotope labeling.

  3. Radioimmunological studies of the thyrotropic function of the hypophysis under the effect of the thyrotropin-releasing hormone in thyroid diseases

    International Nuclear Information System (INIS)

    Vakulenko, A.D.; Matveenko, E.G.; Simakova, G.M.; Sorokina, V.G.; Golubnichaya, L.P.; Dobrova, G.S.

    1979-01-01

    The synthetic thyrotropin-releasing-hormone was stream-injected intravenously to 124 patients and 16 healthy people in doses of 200 μg. It was tolerated satisfactorily at the first and repeated injections. The radioimmunologic method was used prior to the test and 30 min after it to examine thyrotropin content in blood. In normal state the stimulation would result in 3.5-fold increase in thyrotropin level on the average. The hypophysial reserve of thyrotropin was significantly lower in cases of diffuse toxic goiter in grave and semigrave forms and toxic adenoma. It was significantly higher at primary hypothyrosis and retained at nodular euthyroid goiter, neupocirculatopy dystonia and mild thyrotoxicosis. At thyroid gland disturbances the test with thyrotropin-releasing-hormone is of diagnostic value at primary hypothyrosis in the initial latent period; besides, it can be used for control of substitution therapy and as a supplementary test at thyrotoxicosis

  4. Intraindividual variation of triiodothyronine, thyroxine, thyrotropin and thyroxine-binding globulin in fasting serum from healthy men

    International Nuclear Information System (INIS)

    Liappis, N.; Hoffmann, U.; Rao, M.L.

    1986-01-01

    The concentrations of triiodothyronine, thyroxine, thyrotropin and thyroxine-binding globulin were determined in fasting serum from 11 healthy men (age 18-25 years) by radioimmunoassays conducted over a period of 4 weeks on 5 consecutive days per week. The concentrations of thyroxine and thyroxine-binding globulin were very consistent intraindividually, with coefficients of variation of 7.84% and 9.37%, respectively. The triiodothyronine and thyrotropin levels showed significant intraindividual variability with coefficients of variation of 18.38% and 51.85%, respectively. These results point to the type of difficulties encountered in judging serum values, namely intraindividual variations over a given period of time. (orig.) [de

  5. Prolactin, thyrotropin, and growth hormone release during stress associated with parachute jumping.

    Science.gov (United States)

    Noel, G L; Dimond, R C; Earll, J M; Frantz, A G

    1976-05-01

    Prolactin, growth hormone, and thyrotropin (TSH) release during the stress of parachute jumping has been evaluated in 14 male subjects. Subjects were studied at several times before and immediately after their first military parachute jump. All three hormones had risen significantly 1 to 14 min after the jump, compared to mean levels measured immediately beforehand. Earlier studies of physical exercise by ourselves and others would suggest that emotional stress played a role in producing changes of this magnitude. We conclude that prolactin, TSH, and growth hormone are released in physiologically significant amounts in association with the stress of parachute jumping.

  6. Subclinical hyperthyroidism due to a thyrotropin receptor (TSHR) gene mutation (S505R).

    Science.gov (United States)

    Pohlenz, Joachim; Pfarr, Nicole; Krüger, Silvia; Hesse, Volker

    2006-12-01

    To identify the molecular defect by which non-autoimmune subclinical hyperthyroidism was caused in a 6-mo-old infant who presented with weight loss. Congenital non-autoimmune hyperthyroidism is caused by activating germline mutations in the thyrotropin receptor (TSHR) gene. Therefore, the TSHR gene was sequenced directly from the patient's genomic DNA. Molecular analysis revealed a heterozygous point mutation (S505R) in the TSHR gene as the underlying defect. A constitutively activating mutation in the TSHR gene has to be considered not only in patients with severe congenital non-autoimmune hyperthyroidism, but also in children with subclinical non-autoimmune hyperthyroidism.

  7. Structural elucidation of AgAsS2 glass by the analysis of clusters formed during laser desorption ionisation applying quadrupole ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Mawale, Ravi Madhukar; Alberti, Milan; Zhang, Bo; Fraenkl, Max; Wagner, Tomas; Havel, Josef

    2016-03-15

    The structure of AgA(s)S2 glass, which has a broad range of applications, is still not well understood and a systematic mass spectrometric analysis of AgA(s)S2 glass is currently not available. Elucidation of the structure should help in the development of this material. The AgA(s)S2 glass was prepared by the melt-quenched technique. Laser desorption ionisation (LDI) using quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to follow the generation of Ag(m)As(n)S(x) clusters. The stoichiometry of the clusters generated was determined via collision-induced dissociation (CID) and modelling of isotopic patterns. The AgA(s)S2 glass was characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. The LDI of AgA(s)S2 glass leads to the formation of unary (Ag+/− and As(3+)) species, 38 binary (As(n)S(x), Ag(m)S(x)), and 98 ternary (Ag(m)As(n)S(x)) singly charged clusters. The formation of silver-rich nano-grains during AgA(s)S2 glass synthesis has been identified using TEM analysis and also verified by QIT-TOFMS. TOFMS was shown to be a useful technique to study the generation of Ag(m)As(n)S(x )clusters. SEM, TEM and EDX analysis proved that the structure of AgA(s)S2 glass is ‘grain-like’ where grains are either: (1) Silver-rich ‘islands’ (Ag(m,) m up to 39) connected by arsenic and/or sulfur or arsenic sulfide chains or (2) silver sulfide (Ag2S)m (m = 9-20) clusters also similarly inter-connected. This obtained structural information may be useful for the development of ultra-high-density phase-change storage and memory devices using this kind of glass as a base.

  8. Thyroglobulin is a more sensitive indicator of iodine deficiency than thyrotropin: development and evaluation of dry blood spot assays for thyrotropin and thyroglobulin in iodine-deficient geographical areas.

    Science.gov (United States)

    Missler, U; Gutekunst, R; Wood, W G

    1994-03-01

    Immunometric assays were developed for thyrotropin and thyroglobulin using time-resolved fluorescence as the measurement signal. The assays were suitable for measurements in serum/plasma or in dry blood spots (3 mm diameter). Both assays have acceptable coefficients of variation for dry blood spots (intra-assay median CV dry blood spot samples could be transported without special precautions for up to 5-6 weeks without significant loss in immunoreactivity. This agrees with other findings. The results showed that serum thyroglobulin levels are a more sensitive indicator of iodine deficiency than thyrotropin; elevated thyroglobulin levels were found in 182/304 children in Zimbabwe compared with elevated thyrotropin level in 28/304 cases. 213/304 children had enlarged thyroid glands. The cut-off levels used here were 4.5 mU/l thyrotropin and 20 micrograms/l for thyroglobulin, both in whole blood. The assays proved useful for assessing the efficacy of iodine therapy, either by oral dosage or intramuscularly (iodised oil).(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Case report of recurrent atrial fibrillation induced by thyrotropin-secreting pituitary adenoma with Graves' disease.

    Science.gov (United States)

    Li, Jiaqi; Tan, Huiwen; Huang, Juan; Luo, Dan; Tang, Ying; Yu, Ruichao; Huang, Hui

    2018-06-01

    Thyrotropin-secreting adenoma (TSHoma) is rare. Even though the thyrotoxicosis is mild in patients with TSHoma, it is still a rare cause of arrhythmia, ignore of mild disfunction of thyroid function of TSHoma can lead to the delayed diagnosis of pituitary tumor or leading to recurring of complications. Graves' disease is an auto-immue endocrinological disorder. Association of TSHoma and Graves's disease is extremely rare. Coexistence of these two diseases made the diagnosis and treatment complicated. This patient was a 55-year-old man who had been referred to the department of endocrinology and metabolism of the West China Hospital due to recurrent atrial fibrillation (AF) and thyroxicosis. Examinations revealed pituitary thyrotropin-secreting macroadenoma with Graves' disease. We conducted transsphenoidal surgery. Thyrozol was used to treat the recurrence of Graves' disease after pituitary surgery. The TSHoma was successfully cured, and recurrent Graves' disease was controlled very well. The association of TSHoma and Graves' disease is extremely rare. Even though the clinical features of thyrotoxicosis are milder in patients with TSHoma, thyroid function tests are still important clinical assessment of patients with AF, which is an arrhythmia associated with hyperthyroidism. TSHoma is a rare cause of thyrotoxicosis; however, ignoring of the mild disfunction caused by TSHoma can lead to the delayed diagnosis of pituitary tumors or to recurring of complications of TSHoma.

  10. Case report of a pituitary thyrotropin-secreting macroadenoma with Hashimoto thyroiditis and infertility.

    Science.gov (United States)

    Li, Jiaqi; Li, Jianwei; Jiang, Shu; Yu, Ruichao; Yu, Yerong

    2018-01-01

    Thyrotropin-secreting adenoma (TSHoma) is rare, diagnosis and treatment are often delayed if the condition coexists with Hashimoto thyroiditis. The enlarged pituitary adenoma may eventually induce panhypopituitarism, infertility, or the compression of optic nerves and optic chiasma. This patient was a 36-year-old man who had been referred to the pituitary disease multidisciplinary team (MDT) of the West China Hospital, due to infertility. Examinations revealed pituitary thyrotropin-secreting macroadenoma. We conducted trans-sphenoidal surgery. Human chorionic gonadotropin (HCG) and human menopausal gonadotropin (HMG) were used for reproductive reconstruction after surgery. This patient successfully fathered a child. To date, the multidisciplinary team treatment of TSHoma was rare, TSHomas are often misdiagnosed as macroadenomas, because the clinical features are varied and it often takes a long time to be diagnosed. So the purpose of this case report is to attract attention to the manifestation of increased thyroid stimulating hormone (TSH) concentration and discuss MDT treatment for TSH-secreting adenoma. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  11. Clinical experience of a sensitive immunoradiometric thyrotropin (TSH) assay kit (RIA-gnost hTSH)

    International Nuclear Information System (INIS)

    Nakamura, Saeko; Jibiki, Kazuko; Demura, Reiko; Koike, Sachiko; Kurihara, Shigeko; Odagiri, Emi; Demura, Hiroshi

    1987-01-01

    A commercially available immunoradiometric thyrotropin (TSH) assay kit (RIA-gnost hTSH) was used to study the concentration of TSH in serum in a series of 124 patients with thyroid dysfunction and 35 normal controls. Laboratory test for RIA-gnost hTSH showed a detection limit for TSH to be 0.03 μU/ml. The basal serum concentration of TSH in normal controls ranged from 0.17 to 3.21 μU/ml, with a mean of 0.74 μU/ml. It was less than 0.04 μU/ml in all 28 untreated patients with Graves' disease, indicating the discrimination between normal and hyperthyroid subjects. In the case of untreated 7 patients with hypothalamic hypopituitarism, the basal TSH concentration ranged from 0.80 to 13.5 μU/ml. There was no consistent tendency for changes in TSH levels with normalization of free thyroxine in 8 treated patients with Graves' disease. The basal serum concentration of TSH reflected the response of TSH to thyrotropin releasing hormone in 10 treated patients with Graves' disease. The use of the RIA-gnost hTSH would be of clinical significance in the diagnosis and management of patients with Graves' disease or hypopituitarism. (Namekawa, K.)

  12. A comparative study of the clinical features of thyrotropin-secreting pituitary adenomas

    Directory of Open Access Journals (Sweden)

    Xiao-jing FAN

    2017-08-01

    Full Text Available Objective To comparatively analyze the clinical characteristics of thyrotropin-secreting pituitary adenomas (TSH-omas. Methods The clinical features, laboratory variables, imaging and pathological results were retrospectively compared and analyzed of 26 cases with TSH-omas admitted in Chinese PLA General Hospital from Feb. 2006 to Oct. 2016 and 20 cases with TSH-omas admitted in Shanghai Huashan Hospital from Apr. 2006 to Apr. 2013. Results The female ratio was slightly higher in patients of Chinese PLA General Hospital than in Huashan Hospital [(57.7%(15/26 vs. 45.0%(9/20], while the mean age was similar [39.5±14.1(18-67 years vs. 40.0±14.5(17-74 years]. The most common chief complaint was thyrotoxicosis [73.1%(19/26 vs. 55.0%(11/20], and mild-to-moderate goiter was the most common symptom. The mean serum TSH levels in Chinese PLA General Hospital and in Huashan Hospital were 5.06(2.97-6.27mU/L and 6.16(3.76-10.91mU/L respectively, and patients with normal serum TSH levels were more common in Chinese PLA General Hospital than in Huashan Hospital [57.7%(15/26 vs. 40.0%(8/20]. Microadenoma was more common in Chinese PLA General Hospital than in Huashan Hospital [34.62%(9/26 vs. 20.0%(4/20], while macroadenoma was more common in Huashan Hospital than in Chinese PLA General Hospital [20.0%(4/20 vs. 7.7%(2/26]. Microadenoma was more common in female patients of the both groups [66.7%(6/9 vs. 75.0%(3/4], while macroadenoma was all found in male patients. Tumor invasion of surrounding tissue and structure was often found in macroadenoma. In terms of octreotide inhibition test, the range of 24h TSH inhibition rate was roughly the same in the two groups (37.4%-91.8% and 46.5%-94.1%, respectively. Mixed adenoma was rare among all the pathologically confirmed cases. In Chinese PLA General Hospitals, TSH immunoreactive negative neoplastic cells were found in 3 of 8 cases, and octreotide scanning showed negative in 2 of 12 cases. Conclusions Patients with

  13. NR4A1 (Nur77 mediates thyrotropin-releasing hormone-induced stimulation of transcription of the thyrotropin β gene: analysis of TRH knockout mice.

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    Yasuyo Nakajima

    Full Text Available Thyrotropin-releasing hormone (TRH is a major stimulator of thyrotropin-stimulating hormone (TSH synthesis in the anterior pituitary, though precisely how TRH stimulates the TSHβ gene remains unclear. Analysis of TRH-deficient mice differing in thyroid hormone status demonstrated that TRH was critical for the basal activity and responsiveness to thyroid hormone of the TSHβ gene. cDNA microarray and K-means cluster analyses with pituitaries from wild-type mice, TRH-deficient mice and TRH-deficient mice with thyroid hormone replacement revealed that the largest and most consistent decrease in expression in the absence of TRH and on supplementation with thyroid hormone was shown by the TSHβ gene, and the NR4A1 gene belonged to the same cluster as and showed a similar expression profile to the TSHβ gene. Immunohistochemical analysis demonstrated that NR4A1 was expressed not only in ACTH- and FSH- producing cells but also in thyrotrophs and the expression was remarkably reduced in TRH-deficient pituitary. Furthermore, experiments in vitro demonstrated that incubation with TRH in GH4C1 cells increased the endogenous NR4A1 mRNA level by approximately 50-fold within one hour, and this stimulation was inhibited by inhibitors for PKC and ERK1/2. Western blot analysis confirmed that TRH increased NR4A1 expression within 2 h. A series of deletions of the promoter demonstrated that the region between bp -138 and +37 of the TSHβ gene was responsible for the TRH-induced stimulation, and Chip analysis revealed that NR4A1 was recruited to this region. Conversely, knockdown of NR4A1 by siRNA led to a significant reduction in TRH-induced TSHβ promoter activity. Furthermore, TRH stimulated NR4A1 promoter activity through the TRH receptor. These findings demonstrated that 1 TRH is a highly specific regulator of the TSHβ gene, and 2 TRH mediated induction of the TSHβ gene, at least in part by sequential stimulation of the NR4A1-TSHβ genes through a PKC and

  14. Gene expression of thyrotropin- and corticotrophin-releasing hormones is regulated by environmental salinity in the euryhaline teleost Sparus aurata.

    Science.gov (United States)

    Ruiz-Jarabo, Ignacio; Martos-Sitcha, J A; Barragán-Méndez, C; Martínez-Rodríguez, G; Mancera, J M; Arjona, F J

    2018-04-01

    In euryhaline teleosts, the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-interrenal axes (HPT and HPI, respectively) are regulated in response to environmental stimuli such as salinity changes. However, the molecular players participating in this physiological process in the gilthead seabream (Sparus aurata), a species of high value for aquaculture, are still not identified and/or fully characterized in terms of gene expression regulation. In this sense, this study identifies and isolates the thyrotropin-releasing hormone (trh) mRNA sequence from S. aurata, encoding prepro-Trh, the putative factor initiating the HPT cascade. In addition, the regulation of trh expression and of key brain genes in the HPI axis, i.e., corticotrophin-releasing hormone (crh) and corticotrophin-releasing hormone-binding protein (crhbp), was studied when the osmoregulatory status of S. aurata was challenged by exposure to different salinities. The deduced amino acid structure of trh showed 65-81% identity with its teleostean orthologs. Analysis of the tissue distribution of gene expression showed that trh mRNA is, though ubiquitously expressed, mainly found in brain. Subsequently, regulation of gene expression of trh, crh, and crhbp was characterized in fish acclimated to 5-, 15-, 40-, and 55-ppt salinities. In this regard, the brain gene expression pattern of trh mRNA was similar to that found for the crh gene, showing an upregulation of gene expression in seabream acclimated to the highest salinity tested. Conversely, crhbp did not change in any of the groups tested. Our results suggest that Trh and Crh play an important role in the acclimation of S. aurata to hypersaline environments.

  15. Determination of thyrotropin reference values in an adult Mexican population.

    Science.gov (United States)

    Flores-Rebollar, Armando; Moreno-Castañeda, Lidia; Vega-Servín, Norman S; López-Carrasco, Guadalupe; Ruiz-Juvera, Aída

    2015-02-01

    The upper limit of TSH reference level is controversial. The purpose of our study was to determine TSH reference values in a Mexican population in accordance with the National Academy of Clinical Biochemistry (NACB) criteria and in correlation with thyroid ultrasound (US) examination. The study was conducted in volunteers with no known thyroid disease. We recruited 482 subjects, most of them medical or administrative staff from our hospital. They answered a questionnaire on demographic data, family history, co-morbidities, and drug use. Their thyroid hormone levels and thyroid antibodies were determined, and a complete physical examination and thyroid US were performed. The population used to establish the TSH reference intervals was selected according to the NACB criteria and their normal thyroid structural and echogenic characteristics in US examination. Among 482 subjects (209 males) with a median age of 26 years, prevalence rates of TPOAb and TgAb were 9.3% and 10.3% respectively. Mean TSH level in the overall population was 1.90±1.94, with a 97.5th percentile of 6.76 mIU/L. The reference population was limited to 282 subjects (41.5% were excluded) with a mean TSH of 1.86±1.63 and a 97.5th percentile of 4.88 mIU/L. No sex difference was found (p=0.287). Median urinary iodine level in the reference population was 267 μg/L IQR (161.3-482.5). The TSH reference interval in the reference population was 0.71 (CI 0.65-0.77) to 4.88 mIU/L (CI 4.5-5.3); these limits may be influenced by iodine nutritional status in this population. Copyright © 2014 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

  16. Thyrotropin Receptor Autoantibodies in differential diagnosis of hyperthyroidism in children

    Directory of Open Access Journals (Sweden)

    A V Kiyaev

    2006-03-01

    Full Text Available There was investigation carried out in group of 54 children (42 females and 12 males aged between 10.3 and 17.2 years (median - 13. years for the purpose of the estimation of the clinical significance determination of the general autoantibodies to the TSH recepetor (TBII in differential diagnostics hyperthyroidism. In 45 from 54 cases (83.3 % there was Graves’ disease (GD diagnosis set, while high level of TBII was detected amongst 44 from those children (97.8%. Amongst patients with subacute thyroiditis and uninodal toxic goiter together with 7 children, initially estimated by us as “AIT, hyperthyroidism” the values TBII were in limit of reference interval. But for all of that unexpectedly there was detected normal level of Ab-TPO amongst all patients in this group, and - normal echogenic in 6 from 7 cases. From the one hand, high level of Ab-TG and heterogeneous structure may be estimated as particular qualities of hyperthyroidism clinical course during AIT by amongst children. However, absence of the row of diagnostic signs with long-lasting euthyroid condition do not allow us to estimate that cases as hyperthyroidism phase of AIT. From the other hand, we can suppose that we observe the diagnostic of natural clinical course of GD cases in phase of immunological remission. The detection of normal level of TBII in absence of typical clinical signs of GD amongst children with manifestation of hyperthyroidism let us retreat from active therapeutic intervention and choose the method of dynamic observation.

  17. Asparagine-linked oligosaccharides on lutropin, follitropin, and thyrotropin: distributions of sulfated and sialylated oligosaccharides on bovine, ovine, and human pituitary glycoprotein hormones

    International Nuclear Information System (INIS)

    Green, E.D.; Baenziger, J.U.

    1988-01-01

    The asparagine-linked oligosaccharides on the pituitary glycoprotein hormones lutropin (LH), follitropin (FSH), and thyrotropin (TSH) consist of a heterogeneous array of neutral, sulfated, sialylated, and sulfated/sialylated structures. In this study, the authors determined the relative quantities of the various asparagine-linked oligosaccharides on LH, FSH, and TSH from these three animal species. The proportions of sulfated versus sialylated oligosaccharides varied markedly among the different hormones. Both hormone- and animal species-specific differences in the types and distributions of sulfated, sialylated, and sulfated/sialylated structures were evident. In particular, LH and FSH, which are synthesized in the same pituitary cell and bear α-subunits with the identical amino acid sequence, contained significantly different distributions of sulfated and sialylated oligosaccharides. For all three animal species, the ratio of sialylated to sulfated oligosaccharides differed by >10-fold for LH and FSH, with sulfated structures dominating on LH and sialylated structures on FSH. Sialylated oligosaccharides were also heterogeneous with respect to sialic acid linkage (α2,3 versus α2,6). The differences in oligosaccharide structures among the various pituitary glycoprotein hormones as well as among the various glycosylation sites within a single hormone support the hypothesis that glycosylation may serve important functional roles in the expression and/or regulation of hormone bioactivity

  18. Thyroxine and thyrotropin radioimmunoassays using dried blood samples on filter paper for screening of neonatal hypothyroidism

    International Nuclear Information System (INIS)

    Beckers, C.; Cornette, C.; Francois, B.; Bouckaert, A.; Lechat, M.

    1977-01-01

    A routine and automatized methodology for thyroxine (T4) and thyrotropin (TSH) radioimmunoassay (RIA) using dried blood samples on filter paper is described. Five mm diameter dots were prepared. One eluted dot, corresponding to 4 μl of plasma, was used for T4-RIA while two were necessary for TSH-RIA. Reference filter papers were introduced in each assay for quality control. In a preliminary study on 1903 newborns, samples were obtained, generally between the 5th-7th day. Mean dot T4 was 7.38 +- 2.5 μg/dl. Mean dot TSH was 11.83 +- 9.1 μU/ml, the equation of the regression line between dot TSH (y) and serum TSH (x) being Y = 10.29 + 0.623x. (orig.) [de

  19. Circadian variations of serum thyrotropin, thyroxine, triiodothyronine, reverse triiodothyronine, corticosterone and lipids in starved rats

    International Nuclear Information System (INIS)

    Zwirska-Korczala, K.; Ostrowska, Z.; Kucharzewski, M.; Marek, B.; Kos-Kudla, B.; Buntner, B.; Swietochowska, E.

    1993-01-01

    We investigated the circadian variation of serum thyrotropin (TSH), thyroxine (T 4 ), triiodothyronine (T 3 ), reverse triiodothyronine (rT 3 ), corticosterone (B) and lipids in male Wistar rats after one-week starvation. Starvation decreased the TSH level and eliminated its 24-h rhythm. The rhythmicity of oscillations of T 3 and B was maintained. Starvation led to a shift in the acrophase of 24-h T 3 and B oscillation and induced the circadian rhythm of T 4 . The T 3 , T 4 and mesor values were lower, while for rT 3 and B they increased. Lipid concentrations remained unchanged in both experimental and control rats. (author). 27 refs, 3 figs, 2 tabs

  20. The 24-hour profiles of thyrotropin, throxine and triiodothyronine in goitrous and goitre-free Ugandans

    International Nuclear Information System (INIS)

    Kajubi, S.K.

    1980-01-01

    Plasma thyrotropin (TSH), thyroxine (T4) and triiodothyronine (T3) concentrations were measured by radioimmunoassay with commercial assay kits in serial blood samples collected over a 24-hour period from 6 normal and 6 clinically euthyroid but goitrous male Ugandan subjects. Measurements on normal subjects revealed two peaks in plasma TSH concentration, one at about 08.00 hrs, the other at about 20.00 hrs. Plasma T4 concentrations showed two corresponding peaks, while plasma T3 concentrations showed no discernable pattern. Measurement on goitrous subjects revealed only the earlier peak in plasma TSH concentration, while the pooled mean TSH concentration was lower than in normal subjects. Plasma T4 concentrations showed two peaks, as for normal subjects, but the pooled mean T4 concentration was also lower than in normal subjects. Measurements on plasma T3 concentration again showed no discernable pattern. The significance of these findings is discussed

  1. Effects of hyperthyroidism and hypothyroidism on rat growth hormone release induced by thyrotropin-releasing hormone.

    Science.gov (United States)

    Chihara, K; Kato, Y; Ohgo, S; Iwasaki, Y; Maeda, K

    1976-06-01

    The effect of synthetic thyrotropin-releasing hormone (TRH) on the release of growth hormone (GH) and thyroid-stimulating hormone (TSH) was investigated in euthyroid, hypothyroid, and hyperthyroid rats under urethane anesthesia. In euthyroid control rats, intravenous injection of TRH (200 ng/100 g BW) resulted in a significant increase in both plasma GH and TSH. In rats made hypothyroid by treatment with propylthiouracil or by thyroidectomy, basal GH and TSH levels were significantly elevated with exaggerated responses to TRH. In contrast, plasma GH and TSH responses to TRH were both significantly inhibited in rats made hyperthyroid by L-thyroxine (T4) treatment. These results suggest that altered thyroid status influences GH release as well as TSH secretion induced by TRH in rats.

  2. Pituitary Apoplexy After Thyrotropin-releasing Hormone Stimulation Test in a Patient with Pituitary Macroadenoma

    Directory of Open Access Journals (Sweden)

    Huei-Fang Wang

    2007-09-01

    Full Text Available Pituitary apoplexy is a rare complication of pituitary tumors. We report a case of a 41-year-old female with acromegaly due to a pituitary macroadenoma, who developed pituitary apoplexy after a thyrotropin-releasing hormone (TRH 200 mg intravenous injection stimulation test. Neither emergency computed tomography (CT scans nor magnetic resonance imaging (MRI, performed 6 hours and 12 hours, respectively, after the active episode, disclosed the evidence of acute hemorrhage or infarction. Two days later, the pituitary mass, removed by transsphenoidal approach, showed ischemic necrosis and acute hemorrhage. The TRH test is generally safe for evaluating pituitary function, but pituitary apoplexy may occur after the procedure. CT and MRI may miss the diagnosis of pituitary apoplexy, especially if performed immediately after the acute episode.

  3. Quality characteristics of chemicals for the radioimmunoassay of thyroxine and thyrotropin

    International Nuclear Information System (INIS)

    Verdeja I, C.E.

    1994-01-01

    Radioimmunoassay is a form of saturation analysis in which the test material competes with labelled antigen for a limited amount of antibody, the amount of label displaced being a measure of the antigen in the test sample. In this country, the kits for Radioimmunoassay (RIA) are imported, and this increase the cost of it. Because this lack of production, the National Institute of Nuclear Research (ININ) has developed RIA's kits for the thyroxine (T 4 ), Thyrotropin (TSH) and Triyodotironine (T 3 ) hormones. This work presents the conclusions of the test recommended by the WHO. The quality test were: recuperation, cross reactions, basic parameters, intra and inter assay variations, sensibility and others. The results show that the RIA's kits of the ININ have a good behavior and can be use in the clinical laboratory. (Author)

  4. Comparison of pituitary and recombinant human thyrotropin standards in an immunoradiometric system; Comparacion de estandares de tirotropina de origen hipofisario y recombinante en un sistema immunoradiometrico

    Energy Technology Data Exchange (ETDEWEB)

    Blanca Fernandez, Silvia; Rodriguez Gonzalez, Julio Cesar; Nisembaum Alas, Amaparo; Sevy Gonzalez, O [Instituto Nacional de Endocrinologia, La Habana (Cuba)

    1999-12-31

    Results of two standards of human thyrotropin of pituitaries (B) and recombinant (C) origen supplied by the Instituto of pesquisas Energeticas y Nucleares, Brazil, were compared in our immunoradiometric reference system that use an human thyrotropin pituitary standard of local production (A). This work was supported by the International Atomic Energy Agency for an inter-regional comparison and set up of a reference standard

  5. Evaluation of the responsiveness of pituitary gland to thyrotropin releasing hormone (TRH) in rats in the period of 8:00 to 12:00 a.m

    International Nuclear Information System (INIS)

    Borghi, V.C.; Nicolau, W.; Bojarczuk, C.; Pieroni, R.R.

    1977-01-01

    The functional pituitary capacity for the secretion thyrotropin in rats, in relation to the period of time 8:00-12:00 a.m. was studied by means of the administration of synthetic TRH (thyrotropin releasing hormone). The highest pituitary response to the hypothalamic hormone attains its peak between 9:50 and 10:30 a.m., a time in which the gland denotes a high and practically constant level of TSH secretion [pt

  6. The role of thyrotropin suppression in patients with differentiated thyroid carcinoma.

    LENUS (Irish Health Repository)

    Deasy, J

    2010-07-01

    Thyroid carcinoma is the commonest endocrine malignancy. The majority of these are differentiated thyroid carcinomas, which have a good overall prognosis. Treatment includes surgical excision, radio-iodine ablation and long-term thyrotropin suppression. The degree and length of suppression required, as well as the potential side-effect remain controversial. Therefore, the aim of this study was to establish the degree of thyrotropin suppression achieved in a cohort of patients with differentiated thyroid carcinoma. A retrospective review was performed of a prospectively maintained database. All patients with a diagnosis of differentiated thyroid carcinoma between January 1998 and January 2008 were identified. Demographic data, pathological stage and the treatment that the patient received was documented. TSH and free T4 levels were identified at specific time points post-operatively. Eighty-eight patients with differentiated thyroid carcinoma were identified. Seventy patients (79.5%) were female. The mean age was 55, with a range of 18 to 79 years. The majority of patients underwent a total thyroidectomy (n=79; 89.7%) and of those 29 (32.9%) had an associated modified neck dissection. Accurate follow-up was available on forty-nine patients. TSH and free T4 were measured at 3 and 6 months, as well as at 1 and 2 years post-operatively. Adequate TSH suppression was taken at a level < 0.1 mU\\/L. The majority of patients (69.5%) had achieved adequate TSH suppression at 2 years. However, 65% of these same patients had a high free T4 at 2 years indicating a degree of hyperthyroidism. This study has demonstrated that TSH suppression is being adequately achieved in the majority of patients with differentiated thyroid carcinoma. However, this must be carefully weighed against the potential detrimental side-effects of long-term sub-clinical hyperthyroidism.

  7. Childhood lead toxicity and impaired release of thyrotropin-stimulating hormone

    International Nuclear Information System (INIS)

    Huseman, C.A.; Moriarty, C.M.; Angle, C.R.

    1987-01-01

    Decreased stature of children is epidemiologically associated with increased blood lead independent of multiple socioeconomic and nutritional variables. Since endocrine dysfunction occurs in adult lead workers, they studied two girls, 2 years of age, before and after calcium disodium edetate chelation for blood leads (PbB) of 19-72 μg/dl. The height of both children had crossed from the 50th to below the 10th percentile during the course of chronic lead toxicity. Basal free T 4 , T 4 , T 3 , cortisol, somatomedin C, and sex steroids were normal. A decrease in the growth hormone response and elevation of basal prolcatin and gonadotropins were noted in one. Both children demonstrated blunted thyrotropin-stimulating hormone (TSH) responses to thyrotropin-releasing hormone (TRH) in six of seven challenges. This prompted in vitro studies of cultured cells from rat pituitarities. After incubation of pituitary cells with 0.1-10 μM Pb 2+ for 2 hr, followed by the addition of TRH, there was a dose-dependent inhibition of TSH release Lead did not interfere with the assay of TSH. To investigate the interaction of lead and calcium, 45 Ca 2+ kinetic analyses were done on rat pituitary slices after 1 hr incubation with 1.0 μM lead. The impaired late efflux was consistent with a decrease in the size and exchangeability of the tightly bound pool of intracellular microsomal or mitochondrial calcium. The rat pituitary cell model provides a model for the decreased TSH release of lead poisoning, supports the biological plausibility of a neuroendocrine effect on growth, and suggests that interference with calcium-mediated intracellular responses is a basic mechanism of lead toxicity

  8. Signaling-sensitive amino acids surround the allosteric ligand binding site of the thyrotropin receptor.

    Science.gov (United States)

    Kleinau, Gunnar; Haas, Ann-Karin; Neumann, Susanne; Worth, Catherine L; Hoyer, Inna; Furkert, Jens; Rutz, Claudia; Gershengorn, Marvin C; Schülein, Ralf; Krause, Gerd

    2010-07-01

    The thyrotropin receptor [thyroid-stimulating hormone receptor (TSHR)], a G-protein-coupled receptor (GPCR), is endogenously activated by thyrotropin, which binds to the extracellular region of the receptor. We previously identified a low-molecular-weight (LMW) agonist of the TSHR and predicted its allosteric binding pocket within the receptor's transmembrane domain. Because binding of the LMW agonist probably disrupts interactions or leads to formation of new interactions among amino acid residues surrounding the pocket, we tested whether mutation of residues at these positions would lead to constitutive signaling activity. Guided by molecular modeling, we performed site-directed mutagenesis of 24 amino acids in this spatial region, followed by functional characterization of the mutant receptors in terms of expression and signaling, measured as cAMP accumulation. We found that mutations V421I, Y466A, T501A, L587V, M637C, M637W, S641A, Y643F, L645V, and Y667A located in several helices exhibit constitutive activity. Of note is mutation M637W at position 6.48 in transmembrane helix 6, which has a significant effect on the interaction of the receptor with the LMW agonist. In summary, we found that a high proportion of residues in several helices surrounding the allosteric binding site of LMW ligands in the TSHR when mutated lead to constitutively active receptors. Our findings of signaling-sensitive residues in this region of the transmembrane bundle may be of general importance as this domain appears to be evolutionarily retained among GPCRs.

  9. Reproducibility of whole-body {sup 131}I scan and serum thyrotropin and stimulated thyroglobulin values in patients studied twice after injection of recombinant human thyrotropin

    Energy Technology Data Exchange (ETDEWEB)

    Niederkohr, Ryan D.; McDougall, I.R. [Stanford University Medical Center, Division of Nuclear Medicine, Stanford, CA (United States)

    2007-03-15

    Recombinant human TSH (rhTSH) is used to increase radioiodine uptake during imaging of thyroid cancer, obviating the need to render the patient hypothyroid. We assessed the reproducibility of radioiodine uptake, serum thyrotropin (TSH), and stimulated serum thyroglobulin (Tg) levels after rhTSH administration. A retrospective review was performed of patients at Stanford who underwent whole-body {sup 131}I scanning for surveillance of thyroid cancer twice after thyroidectomy and {sup 131}I ablation, with rhTSH prior to each scan. Forty-eight hour radioiodine uptake, peak serum TSH, and stimulated serum Tg levels for each study were recorded. Paired t tests and correlation analysis were used to assess interexamination repeatability. Twenty-three patients underwent two scintiscans with rhTSH, for a total of 46 exams. There was no significant difference between percent uptake at 48 h in the paired exams (p=0.40). Serum TSH level was measured in 45 of 46 exams; TSH exceeded 50 mIU/l in all cases, and there was no significant difference between paired TSH levels (p=0.93). All patients had stimulated serum Tg levels measured, with no significant difference between paired Tg levels (p=0.40); after excluding one patient whose Tg changed from 15.8 ng/ml to undetectable between scans without interval treatment, the p value rose to 0.95. There was a strong correlation among paired uptake values (r=0.85, p<0.0001), peak serum TSH (r=0.69, p=0.0003), and stimulated Tg levels (r=0.81, p<0.0001). No discordant scan interpretations were reported. Forty-eight hour radioiodine uptake, peak serum TSH, and stimulated serum Tg levels after administration of rhTSH are repeatable between studies, demonstrating reproducibility of diagnostic results without rendering patients hypothyroid. (orig.)

  10. Isolation and Elucidation of 15-Acetylguanacone from Soursop ...

    African Journals Online (AJOL)

    ADOWIE PERE

    002/C. The structure of compound 200/A2 was elucidated using 1H-NMR spectroscopy, infrared spectroscopy .... Molecular Docking Experiments, Protein preparation ... ligand conformations in the binding sites through the .... Molecular dynamics simulation of diacetyl-guancone. Bioorgnic and Medicinal Chemistry 15: 4369-.

  11. Production of thyrotropin receptor antibodies in acute phase of infectious mononucleosis due to Epstein-Barr virus primary infection: a case report of a child.

    Science.gov (United States)

    Nagata, Keiko; Okuno, Keisuke; Ochi, Marika; Kumata, Keisuke; Sano, Hitoshi; Yoneda, Naohiro; Ueyama, Jun-Ichi; Matsushita, Michiko; Kuwamoto, Satoshi; Kato, Masako; Murakami, Ichiro; Kanzaki, Susumu; Hayashi, Kazuhiko

    2015-01-01

    Various autoantibodies have been reported to be detected during the progression of infectious mononucleosis. We observed a case of infectious mononucleosis due to Epstein-Barr virus primary infection for 2 months, and noticed the transiently increased titer of thyrotropin receptor autoantibodies detected at the acute phase on the 3rd day after admission. At that time, real-time quantitative PCR also revealed the mRNA expressions of an immediate early lytic gene, BZLF1, and a latent gene, EBNA2. The expression of BZLF1 mRNA means that Epstein-Barr virus infects lytically, and EBNA2 protein has an important role in antibody production as well as the establishment of Epstein-Barr virus latency. These results suggest that Epstein-Barr virus lytic infection is relevant to thyrotropin receptor autoantibody production. Thyrotropin receptor autoantibodies stimulate thyroid follicular cells to produce excessive thyroid hormones and cause Graves' disease. Recently, we reported the thyrotropin receptor autoantibody production from thyrotropin receptor autoantibody-predisposed Epstein-Barr virus-infected B cells by the induction of Epstein-Barr virus lytic infection in vitro. This case showed in vivo findings consistent with our previous reports, and is important to consider the pathophysiology of Graves' disease and one of the mechanisms of autoimmunity.

  12. Spinal cord thyrotropin releasing hormone receptors of morphine tolerant-dependent and abstinent rats

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, N.H.; Gulati, A.; Bhargava, H.N. (Univ. of Illinois, Chicago (USA))

    1990-07-01

    The effect of chronic administration of morphine and its withdrawal on the binding of 3H-(3-MeHis2)thyrotropin releasing hormone (3H-MeTRH) to membranes of the spinal cord of the rat was determined. Male Sprague-Dawley rats were implanted with either 6 placebo or 6 morphine pellets (each containing 75-mg morphine base) during a 7-day period. Two sets of animals were used. In one, the pellets were left intact at the time of sacrificing (tolerant-dependent) and in the other, the pellets were removed 16 hours prior to sacrificing (abstinent rats). In placebo-pellet-implanted rats, 3H-MeTRH bound to the spinal cord membranes at a single high affinity binding site with a Bmax of 21.3 +/- 1.6 fmol/mg protein, and an apparent dissociation constant Kd of 4.7 +/- 0.8 nM. In morphine tolerant-dependent or abstinent rats, the binding constants of 3H-MeTRH to spinal cord membranes were unaffected. Previous studies from this laboratory indicate that TRH can inhibit morphine tolerance-dependence and abstinence processes without modifying brain TRH receptors. Together with the present results, it appears that the inhibitory effect of TRH on morphine tolerance-dependence and abstinence is probably not mediated via central TRH receptors but may be due to its interaction with other neurotransmitter systems.

  13. Prolactin response to thyrotropin-releasing hormone in early and advanced human breast cancer

    International Nuclear Information System (INIS)

    Barni, S.; Lissoni, P.; Tancini, G.

    1986-01-01

    While prolactin (PRL) has been shown to stimulate the development of mammary carcinoma in several animal species, its role in human breast cancer remains to be established. To further investigate PRL secretion in human breast cancer, its basal levels and response to thyrotropin-releasing hormone (TRH) were evaluated in 16 patients (6 with no metastases and 10 with metastatic locations). The control group consisted of 19 healthy women. High PRL basal concentrations were seen in 2 patients only; no significant differences were found between the other patients and the normal subjects. The PRL increase induced by TRH administration was significantly higher in patients than in controls. Finally a change in the hormonal secretion was found after chemotherapy in 3 of the 5 patients in whom PRL response to TRH was evaluated either before or 10-12 days after a cycle of intravenous CMF adjuvant chemotherapy. These results demostrate the existence of an exaggerated response of PRL to TRH in patients with breast cancer, even in the presence of normal basal levels. Moreover, they would seem to suggest a possible influence of CMF on PRL response to TRH stimulation

  14. Thyrotropin-releasing hormone (TRH promotes wound re-epithelialisation in frog and human skin.

    Directory of Open Access Journals (Sweden)

    Natalia T Meier

    Full Text Available There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression. Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters.

  15. Characterization of monoclonal antibodies against human thyrotropin and use in an immunoradiometric assay and immunohistochemistry

    International Nuclear Information System (INIS)

    Benkirane, M.; Bon, D.; Bellot, F.; Prince, P.; Delori, P.; Hassoun, J.; Carayon, P.

    1987-01-01

    Monoclonal antibodies were prepared against human thyrotropin. 13 different antibodies were characterized. Ten antibodies were of the IgG1 subclass. The affinities of the antibodies were in the range 10 9 -10 11 mol -1 .l. Four of them were specific for hTSH and did not react with hLH, hFSH, hCG or αhCG. Four reacted with these hormones and recognized the α subunit of hCG. One cross-reacted only with HFSH. The remaining four antibodies recognized the holo-hTSH only, and thus were designated as anti-conformational determinants. Monoclonal antibodies reacting with different antigenic determinants on the hTSH molecule defined seven clusters. Two of them were used to develop a simplified two-site sandwich radioimmunoassay in which one monoclonal antibody was immobilized on tubes (anti-βTSH) and another (anti-α) labelled with 125 I. This assay was highly specific and demonstrated a sensitivity level of 0.1 μIU/ml. Two monoclonal antibodies were used in immunohistochemistry and their quality and specificity was assessed in the detection of hTSH immunoreactivity in human pituitary biological sections. 20 refs.; 6 figs.; 2 tabs

  16. Thyrotropin-Releasing Hormone (TRH) Promotes Wound Re-Epithelialisation in Frog and Human Skin

    Science.gov (United States)

    Zhang, Guo-You; Emelianov, Vladimir; Paredes, Roberto; Debus, Sebastian; Augustin, Matthias; Funk, Wolfgang; Amaya, Enrique; Kloepper, Jennifer E.; Hardman, Matthew J.; Paus, Ralf

    2013-01-01

    There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis) skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH) as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression). Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters. PMID:24023889

  17. Autoradiographic localization of thyrotropin releasing hormone (TRH) receptors in the central nervous system

    International Nuclear Information System (INIS)

    Manaker, S.

    1985-01-01

    Quantitative autoradiography was used to examine the distribution of thyrotropin-releasing hormone (TRH) receptors in the rat and human central nervous system (CNS). The binding of [ 3 H]-3-methyl-histidine 2 -TRH ([ 3 H]-MeTRH) to TRH receptors was saturable, of a high affinity (K/sub d/ = 5 nM), and specific for TRH analogs. Studies with neurotoxins ibotenic acid and 6-hydroxydopamine (6-OHDA) suggest that TRH receptors within the amygdala are predominantly located on cell bodies, and not nerve terminals. Finally, an examination was made of the concentrations of TRH receptors in spinal cords of patients with amyotrophic lateral sclerosis (ALS), a degenerative disease of the motor neurons located in Lamina IX. Large decreases in TRH receptors were noted in ALS spinal cords, when compared to non-neurological controls, probably reflecting the loss of motor neurons. In addition, decreases in the TRH receptor concentration of Lamina II were observed. This finding may reflect the sensitivity of neurons throughout the CNS to the pathophysiologic mechanisms of neuronal degeneration which cause ALS

  18. Thyrotropin-secreting pituitary adenomas: biological and molecular features, diagnosis and therapy.

    Science.gov (United States)

    Losa, M; Fortunato, M; Molteni, L; Peretti, E; Mortini, P

    2008-12-01

    Central hyperthyroidism due to a thyrotropin (TSH)-secreting pituitary adenoma is a rare cause of hyperthyroidism, representing 0.5-1.0% of all pituitary adenomas. The etiopathogenesis of TSH-secreting-adenomas is unknown and no definite role for various oncogenes has been proven. Patients with TSH-secreting adenoma usually present with signs and symptoms of hyperthyroidism milder than those in patients with hyperthyroidism of thyroid origin, in addition to symptoms secondary to mass effects of the pituitary tumour. Mixed pituitary tumours co-secrete growth hormone and prolactin. The characteristic biochemical abnormalities are normal or high serum TSH concentrations in the presence of elevated total and/or free thyroid hormones concentrations. Measurement of markers of peripheral thyroid hormone action and dynamic tests may aid in the differential diagnosis with the syndrome of resistance to thyroid hormone. Neuroimaging is fundamental to visualize the pituitary tumor. Therapy of TSH-secreting adenomas can be accomplished by surgery, radiation therapies, and medical treatment with somatostatin analogs or dopamine agonists. Nowadays, and in contrast with the first reports on this rare disease, most patients are well controlled by current therapies.

  19. Thyrotropin receptor autoantibodies and early miscarriages in patients with Hashimoto thyroiditis: a case-control study.

    Science.gov (United States)

    Toulis, Konstantinos A; Goulis, Dimitrios G; Tsolakidou, Konstantina; Hilidis, Ilias; Fragkos, Marios; Polyzos, Stergios A; Gerofotis, Antonios; Kita, Marina; Bili, Helen; Vavilis, Dimitrios; Daniilidis, Michail; Tarlatzis, Basil C; Papadimas, Ioannis

    2013-08-01

    We have previously hypothesized that early miscarriage in women with Hashimoto thyroiditis might be the result of a cross-reactivity process, in which blocking autoantibodies against thyrotropin receptor (TSHr-Ab) antagonize hCG action on its receptor on the corpus luteum. To test this hypothesis from the clinical perspective, we investigated the presence of TSHr-Ab in Hashimoto thyroiditis patients with apparently unexplained, first-trimester recurrent miscarriages compared to that in Hashimoto thyroiditis patients with documented normal fertility. A total of 86 subjects (43 cases and 43 age-matched controls) were finally included in a case-control study. No difference in the prevalence of TSHr-Ab positivity was detected between cases and controls (Fisher's exact test, p value = 1.00). In patients with recurrent miscarriages, TSHr-Ab concentrations did not predict the number of miscarriages (univariate linear regression, p value = 0.08). These results were robust in sensitivity analyses, including only cases with full investigation or those with three or more miscarriages. We conclude that no role could be advocated for TSHr-Ab in the aetiology of recurrent miscarriages in women with Hashimoto thyroiditis.

  20. Radioimmunoassay of thyrotropin releasing hormone in human serum and its clinical application

    International Nuclear Information System (INIS)

    Zhao Zhiying; Liu Shizhen

    1995-01-01

    The study was aimed at investigating the relationship between the TRH level in peripheral blood and the physiological, pathophysiological variation of the hypothalamic-pituitary-thyroid axis, especially at studying the relationship between TRH level and various thyroid function states as well as its clinical significance. A highly sensitive, specific radioimmunoassay of the thyrotropin releasing hormone (TRH) has been developed in the laboratory using 125 I labeled anti-TRH antibodies. Blood samples were collected in tubes containing a mixture of 8-hydroxyquinoline sulfur, Tween 20 and EDTA-2NA(E). The sensitivity was 8.3% pmol/L, and the intra- and inter-assay coefficients of variation were 2.5%∼4.9% and 8.9%∼10.0% respectively. The recovery rate ranged from 92%∼105%. The TRH levels in sera of 80 normals and 324 patients with pituitary thyroid diseases were measured with this assay. The results show a significant decrease of TRH levels in hyperthyroid patients and increase in hypothyroid subjects. The TRH levels in patients with nodular goiter and cold nodules, pituitary dwarfism and pituitary tumours were not significantly different from those of the normal group. The results demonstrated that measurement of TRH level in peripheral blood is useful in investigating the physiological and pathophysiological status of the hypothalamic-pituitary-thyroid axis function and the change in TRH levels has close relations with the thyroid function

  1. Cord blood thyrotropin screening for congenital hypothyroidism. Three years' experience on the Island of Saint Lucia.

    Science.gov (United States)

    Sajous, C; Goto, M; Fitzgerald, M; Anderson, C L; Craft, W; Hurley, R M; Zeller, W P

    1991-01-01

    Cord blood thyrotropin (TSH) screening for congenital primary hypothyroidism has been in effect on the island of St. Lucia for the past three years. Umbilical cord blood samples are obtained on Guthrie filter paper and then transported 3,000 miles to Loyola University of Chicago and delivered to the Illinois State Metabolic Screening Laboratory. There TSH is measured by radioimmunoassay (RIA). After three years, 1,789 newborns have been screened, and the mean value is 6.23 +/- 0.13 microIU per ml. This mean value is less than previously reported by us in 1986 (10.23 +/- 0.29 microIU per ml).13 It is concluded that this screening service continues to be possible far removed from the population under observation. No case of primary hypothyroidism has been detected. Our decreased mean TSH value is due to the new method currently used by the Illinois State Metabolic Screening Laboratory. Congenital hypothyroidism will not be missed provided internal controls are established and rigidly observed.

  2. Elucidating Functional Aspects of P-type ATPases

    DEFF Research Database (Denmark)

    Autzen, Henriette Elisabeth

    2015-01-01

    and helped enlighten how thapsigargin, a potent inhibitor of SERCA1a, depends on a water mediated hydrogen bond network when bound to SERCA1a. Furthermore, molecular dynamics (MD) simulations of the same P-type ATPase were used to assess a long-standing question whether cholesterol affects SERCA1a through...... similar to that of the wild type (WT) protein. The discrepancy between the newly determined crystal structure of LpCopA and the functional manifestations of the missense mutation in human CopA, could indicate that LpCopA is insufficient in structurally elucidating the effect of disease-causing mutations...... in the human CopA proteins. MD simulations, which combine coarse-grained (CG) and atomistic procedures, were set up in order to elucidate mechanistic implications exerted by the lipid bilayer on LpCopA. The MD simulations of LpCopA corroborated previous and new in vivo activity data and showed...

  3. Standardization of human thyrotropin radioimmunoassay and its application to the purification of this hormone to the preparation of the assay reagents

    International Nuclear Information System (INIS)

    Lin, L.H.

    1991-01-01

    The various steps that are necessary for setting up the thyrotropin radioimmunoassay are presented below. Radioiodination was carried out through the Chloramine T method and the labeled purification performed on Sephadex G-100. Purification of human thyrotropin from side fractions obtained during the purification of growth hormone was carried out in order to obtain a pure reagent for use in the radioimmunoassay. The employment of the hormone obtained was evaluated as the radioimmunoassay tracer in comparison with that prepared from the hormone received from the NIDDKD, U.S.A. The results indicated that although it was not possible to obtain a hormone with a purity degree adequate to be used as the tracer, enough experience was acquired for the isolation of thyrotropin. (author)

  4. Metabolomic elucidation of pork from different crossbreds

    DEFF Research Database (Denmark)

    Bertram, Hanne Christine S.; Straadt, Ida Krestine; Clausen, Morten Rahr

    , and correlations between individual metabolites and sensory attributes were elucidated. A high content of carnosine in the meat was associated with a low value of many sensory attributes related to meat flavor/taste. Surprsingly, IMP and inosine were in general not correlated with sensory attributes related...... to meat flavor/taste. Water-holding capacity and oxygen radical absorbance capacity (ORAC) of the meat were determined to elucidate the correlations between individual metabolites and these two parameters that are of importance for the technological meat quality. In conclusion, the present study reveals...

  5. Structural elucidation of transmembrane domain zero (TMD0) of EcdL: A multidrug resistance-associated protein (MRP) family of ATP-binding cassette transporter protein revealed by atomistic simulation.

    Science.gov (United States)

    Bera, Krishnendu; Rani, Priyanka; Kishor, Gaurav; Agarwal, Shikha; Kumar, Antresh; Singh, Durg Vijay

    2017-09-20

    ATP-Binding cassette (ABC) transporters play an extensive role in the translocation of diverse sets of biologically important molecules across membrane. EchnocandinB (antifungal) and EcdL protein of Aspergillus rugulosus are encoded by the same cluster of genes. Co-expression of EcdL and echinocandinB reflects tightly linked biological functions. EcdL belongs to Multidrug Resistance associated Protein (MRP) subfamily of ABC transporters with an extra transmembrane domain zero (TMD0). Complete structure of MRP subfamily comprising of TMD0 domain, at atomic resolution is not known. We hypothesized that the transportation of echonocandinB is mediated via EcdL protein. Henceforth, it is pertinent to know the topological arrangement of TMD0, with other domains of protein and its possible role in transportation of echinocandinB. Absence of effective template for TMD0 domain lead us to model by I-TASSER, further structure has been refined by multiple template modelling using homologous templates of remaining domains (TMD1, NBD1, TMD2, NBD2). The modelled structure has been validated for packing, folding and stereochemical properties. MD simulation for 0.1 μs has been carried out in the biphasic environment for refinement of modelled protein. Non-redundant structures have been excavated by clustering of MD trajectory. The structural alignment of modelled structure has shown Z-score -37.9; 31.6, 31.5 with RMSD; 2.4, 4.2, 4.8 with ABC transporters; PDB ID 4F4C, 4M1 M, 4M2T, respectively, reflecting the correctness of structure. EchinocandinB has been docked to the modelled as well as to the clustered structures, which reveals interaction of echinocandinB with TMD0 and other TM helices in the translocation path build of TMDs.

  6. Isolation and structural elucidation of secondary metabolites from plants of the family Flacourtiaceae and Asclepiadaceae, and evaluation of biological activity of the sesquiterpene lactones and the diterpenes of Casearia sp

    International Nuclear Information System (INIS)

    Binns Quiros, Franklin

    2012-01-01

    A phytochemical study was realized of the plants Casearia aculeata, Casearia nitida and Asclepias verticillata, using experiments of nuclear magnetic resonance (NMR) of one and two dimensions. Ten secondary metabolites are isolated from C. aculeata and C. nitida. Three of the secondary metabolites have presented a structure known: a diterpene type kaurane: ent-kaurenic acid, a diterpene type pimarane: oxide of 3β-hydroximanoil and a steroid: 4-stigmastene-3-ona. Seven remaining compounds have corresponded to diterpene type clerodane of novel structure. Eight glycosides of poly oxidized pregnanes of novel structure are isolated from A. verticillata. In vitro tests of cytotoxicity and induction of caspase-3 are performed on leukemia cells type Jurkat T. These tests were performed at fifteen sesquiterpene lactones and at four diterpenes. The tests developed have had the purpose to describe structure-activity relationships that can be linked with the capacity to inhibit the factor NF-κB (sesquiterpene lactones) described in the literature and with the known mechanism of action induction of apoptosis in diterpenes type clerodane. A clear relationship between the capacity (high, intermediate or low) to inhibit the factor NF-κB and the capacity to induce to the caspase-3 has remained without observation in the sesquiterpene lactones. Some structural comparisons related with the cytotoxic capacity and the induction of the caspase-3 have been described for the series of LSs with carbon structure of pseudoguianolides. Diterpenes with carbon structure of diterpenes type clerodane have had greater cytotoxic activity with respect to without carbon structure. Diterpenes type clerodane isolated from the family Flacourtiaceae have been cytotoxics, their capacity to induce to the caspase-3 has remained without be nearby to induction realized by the actinomycin D (pure inducer of the caspase-3). (author) [es

  7. Does Pictorial Elucidation Foster Recollection of Idioms?

    Science.gov (United States)

    Boers, Frank; Piquer Piriz, Ana Maria; Stengers, Helene; Eyckmans, June

    2009-01-01

    Experimental evidence suggests that pictorial elucidation helps learners comprehend and remember the meaning of second language (L2) idioms. In this article we address the question whether it also helps retention of the form of idioms, i.e. their precise lexical composition. In a small-scale experiment, the meaning of English idioms was clarified…

  8. Synthesis and NMR Elucidation of Novel Pentacycloundecane ...

    African Journals Online (AJOL)

    Herein we report the synthesis and NMR elucidation of five novel pentacycloundecane (PCU)-derived short peptides as potential HIV protease inhibitors. 1H and 13C spectral analysis show major overlapping of methine resonance of the PCU 'cage' thereby making it extremely difficult to assign the NMR signals. Attachment ...

  9. Synthesis and NMR elucidation of novel pentacycloundecane ...

    African Journals Online (AJOL)

    NICO

    SYNTHESIS AND NMR ELUCIDATION OF NOVEL. PENTACYCLOUNDECANE DERIVED PEPTIDES. Rajshekhar Karpoormath, a. Oluseye K. Onajole, a. Thavendran Govender, b. Glenn E. M. Maguire, a and Hendrik G. Kruger a* a. School of Chemistry, University of KwaZulu-Natal, Durban 4001, South Africa b. School of ...

  10. Total Thyroidectomy for Thyroid Cancer Followed by Thyroid Storm due to Thyrotropin Receptor Antibody Stimulation of Metastatic Thyroid Tissue

    DEFF Research Database (Denmark)

    Folkestad, Lars; Brandt, Frans; Brix, Thomas

    2017-01-01

    BACKGROUND: Graves disease (GD) is an autoimmune condition characterized by the presence of antibodies against the thyrotropin receptor (TRAB), which stimulate the thyroid gland to produce excess thyroid hormone. Theoretically, TRAB could stimulate highly differentiated thyroid cancer tissue and...... treatment continued until after the fourth RAI dose. Hypothyroidism did not occur until following the fifth RAI treatment. SUMMARY AND CONCLUSIONS: We present a patient initially diagnosed with thyrotoxicosis and subsequently with metastatic follicular variant of papillary thyroid cancer. It is suggested...... that TRAB stimulated the highly differentiated extrathyroidal metastatic thyroid tissue to produce excessive amounts of thyroid hormone, delayed diagnosis, and potential aggravation of the course of thyroid cancer....

  11. Circadian variations of thyrotropin (TSH), triiodothyronine (T3) and thyroxine (T4) in surgical and functional pinealectomy in rats

    International Nuclear Information System (INIS)

    Ostrowska, Z.; Zwirska-Korczala, K.; Buntner, B.; Jarzab, B.; Kucharzewski, M.

    1994-01-01

    The aim of the present study was to determine the regulatory influence of surgical and functional pinealectomy on circadian variations of thyrotropin (TSH), triiodothyronine (T 3 ) and thyroxine (T 4 ) in male Wistar rats. The serum hormone levels were estimated with RIA method, and the circadian rhythm secretion was analyzed by means of cosinor method. Our study shows that there are marked differences in circadian fluctuations of T 3 and T 4 between the two generally used models of pinealectomy. (author). 55 refs, 4 figs

  12. Determination of congenital hypothyroidism in neonatal by immunoradiometric assays of thyrotropin

    International Nuclear Information System (INIS)

    Contreras P, E.

    1998-01-01

    The congenital hypothyroidism is the endocrine illness more frequent of the childhood, it is the one that produce the devastating effects on the growth and the development. It represent one of the few causes of mental delay that it could be prevented if it is diagnosed and treaty on time. The infants affected with congenital hypothyroidism, could be detected for the apparent presence of some physical abnormalities, which comes the first days of the birth. Unfortunately, in the moment in which the classical manifestations are made present, it is very probable that cerebral damage already exists, for what the affected children should be tried before the three months of life administering them thyroid hormones. In Mexico the incidence of the congenital hypothyroidism is of one for each 1612 births for that is very important in the area of Public Health diagnose in early form and with certainty the congenital hypothyroidism. The TSH hormone or thyrotropin is formed in the hypophysis and intervenes in the synthesis of the thyroid hormones (T3, T4) when the concentration of these is adapted, the formation of TSH is inhibited, for that upon lacking the thyroid hormones the concentration of TSH in the blood is high. For these reasons the shot metabolic state of a newborn could be determined, quantifying the TSH in blood obtained by heel stab of the neonatal, or in coming blood from the umbilical cord, after 48 hours of being born. However because the TSH is similar to other hormones and is in extremely low concentrations, it is made necessary appeal analytic techniques of very sensitive and specific laboratory like the Immunoradiometric assays (Irma) in order to could determine the levels of this hormone in the blood. (Author)

  13. Functional diagnostics for thyrotropin hormone receptor autoantibodies: bioassays prevail over binding assays.

    Science.gov (United States)

    Lytton, Simon David; Schluter, Anke; Banga, Paul J

    2018-06-01

    Autoantibodies to the thyrotropin hormone receptor (TSH-R) are directly responsible for the hyperthyroidism in Graves' disease and mediate orbital manifestations in Graves' orbitopathy (otherwise known as thyroid eye disease). These autoantibodies are heterogeneous in their function and collectively referred to as TRAbs. Measurement of TRAbs is clinically important for diagnosis of a variety of conditions and different commercial assays with high sensitivity and specificity are available for diagnostic purposes. This review provides overwhelming evidence that the TRAbs detected in binding assays by mainly the automated electrochemical luminescence immunoassays (ECLIA) do not distinguish TRAbs that stimulate the TSH-R (called TSIs or TSAbs) and TRAbs that just inhibit the binding of TSH without stimulating the TSH-R (called TBAbs). However, TSAbs and TBAbs have divergent pathogenic roles, and depending which fraction predominates cause different clinical symptoms and engender different therapeutic regimen. Therefore, diagnostic distinction of TSAbs and TBAbs is of paramount clinical importance. To date, only bioassays such as the Mc4 TSH-R bioassay (Thyretain TM , Quidel) and the Bridge assay (Immulite 2000, Siemens) can measure TSAbs, with only the former being able to distinguish between TSAbs and TBAbs. On this note, it is strongly recommended to only use the term TSI or TSAb when reporting the results of bioassays, whereas the results of automated TRAb binding assays should be reported as TRAbs (of undetermined functional significance). This review aims to present a technical and analytical account of leading commercial diagnostic methods of anti-TSH-R antibodies, a metaanalysis of their clinical performance and a perspective for the use of cell based TSH-R bioassays in the clinical diagnostics of Graves' disease.

  14. Thyrotropin - Binding Inhibiting Immunoglobulin (TBII) in Patients with Autoimmune Thyroid Diseases

    International Nuclear Information System (INIS)

    Jang, Dae Sung; Ahn, Byeong Cheol; Sohn, Sang Kyun; Lee, Jae Tae; Lee, Kyu Bo

    1996-01-01

    In order to evaluate the significance of thyrotropin-binding inhibiting immunoglobulin (TBII) in the patients with autoimmune thyroid diseases, the authors investigated 402 cases of Graves' disease and 230 cases of Hashimoto's thyroiditis comparing 30 cases of normal healthy adult at Kyung Pook University Hospital from February 1993 to August 1994. The TBII was tested by radioimmunoassay and assessed on the dynamic change with the disease course, thyroid functional parameters, and other thyroid autoantibodies; antithyroglobulin antibody(ATAb) and antimicrosomal antibody(AMAb) including thyroglobulin. The serum level of TBII was 40.82 ± 21.651(mean ± SD)% in hyperthyroid Graves' disease and 8.89 ± 14.522% in Hashimoto's thyroiditis and both were significant different from normal control of which was 3.21 ± 2.571%. The frequency of abnormally increased TBII level was 92.2% in hyperthyroid Craves' disease, 46.7% in euthyroid Graves' disease or remission state of hyperthyroidism, and 23.9% in Hashimoto's thyroiditis. The serum levels of increased TBII in Graves' disease were positively correlated with RAIU, serum T3, T4, and FT4, but negatively correlated with serum TSH(each p<0.001). The TBII in Graves' disease had significant positive correlation with serum thyroglobulin and AMAb, but no significant correlation with ATAb. In the Hashimoto's thyroiditis, the serum levels of TBII were positively correlated with RAIU, serum T3, TSH and AMAb, but not significantly correlated with serum T4, FT4, thyroglobulin and ATAb. Therefore serum level of TBII seemed to be a useful mean of assessing the degree of hyperthyroidism in Graves' disease and correlated well with thyroidal stimulation. The serum level of TBII in Hashimoto's thyroiditis is meaningful for the degree of both functional abnormality reflecting either hyperfunction or hypofunction and the immunologic abnormality.

  15. Thyrotropin Receptor and Membrane Interactions in FRTL-5 Thyroid Cell Strain in Microgravity

    Science.gov (United States)

    Albi, E.; Ambesi-Impiombato, F. S.; Peverini, M.; Damaskopoulou, E.; Fontanini, E.; Lazzarini, R.; Curcio, F.; Perrella, G.

    2011-01-01

    The aim of this work was to analyze the possible alteration of thyrotropin (TSH) receptors in microgravity, which could explain the absence of thyroid cell proliferation in the space environment. Several forms of the TSH receptor are localized on the plasma membrane associated with caveolae and lipid rafts. The TSH regulates the fluidity of the cell membrane and the presence of its receptors in microdomains that are rich in sphingomyelin and cholesterol. TSH also stimulates cyclic adenosine monophosphate (cAMP) accumulation and cell proliferation. Reported here are the results of an experiment in which the FRTL-5 thyroid cell line was exposed to microgravity during the Texus-44 mission (launched February 7, 2008, from Kiruna, Sweden). When the parabolic flight brought the sounding rocket to an altitude of 264km, the culture media were injected with or without TSH in the different samples, and weightlessness prevailed on board for 6 minutes and 19 seconds. Control experiments were performed, in parallel, in an onboard 1g centrifuge and on the ground in Kiruna laboratory. Cell morphology and function were analyzed. Results show that in microgravity conditions the cells do not respond to TSH treatment and present an irregular shape with condensed chromatin, a modification of the cell membrane with shedding of the TSH receptor in the culture medium, and an increase of sphingomyelin-synthase and Bax proteins. It is possible that real microgravity induces a rearrangement of specific sections of the cell membrane, which act as platforms for molecular receptors, thus influencing thyroid cell function in astronauts during space missions.

  16. The utility of peripheral thyrotropin receptor mRNA in the management of differentiated thyroid cancer.

    Science.gov (United States)

    Aliyev, Altay; Soundararajan, Saranya; Bucak, Emre; Gupta, Manjula; Hatipoglu, Betul; Nasr, Christian; Siperstein, Allan; Berber, Eren

    2015-10-01

    Our aim was to analyze the utility of peripheral thyrotropin receptor (TSHR) messenger RNA (mRNA) in predicting and detecting the recurrence of differentiated thyroid cancer. Peripheral blood TSHR-mRNA was obtained in 103 patients before and after total thyroidectomy. An analysis was performed to correlate peripheral blood TSHR-mRNA concentration with oncologic outcomes. Tumor types were papillary (n = 92), follicular (n = 9) and Hürthle cell (n = 2) cancer. Preoperative TSHR-mRNA was ≥1.02 ng/μg in 85% (88/103). On follow-up (median 48 months), 10 patients (10 %) developed recurrence. Recurrence rate in patients with a preoperative TSHR-mRNA ≥ 1.02 ng/μg was 11% versus 0% in those with a lesser concentration. TSHR-mRNA correctly diagnosed 7 (70%) of 10 recurrences. Of 19 patients with positive thyroglobulin (Tg) antibodies, TSHR-mRNA confirmed disease-free status in 12 (63%) and recurrence in 1 (5%). For Tg, TSHR-mRNA and whole-body radioactive iodine scan, sensitivity was 70%, 70%, and 75%; specificity 94%, 76%, 97%; PPV 54%, 24%, and 67%; and NPV 97%, 96%, and 98%, respectively, in detecting recurrent disease. This study shows that patients with preoperative TSHR-mRNA ≥1.02 ng/μg may be at a greater risk for recurrence compared with those with a lesser concentration. In the presence of Tg antibodies, TSHR-mRNA accurately predicted disease status in 68% of patients. Its overall performance in detecting recurrence was similar to Tg and whole-body radioactive iodine scan, albeit with lower specificity and PPV. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Seasonal and pulsatile dynamics of thyrotropin and leptin in mares maintained under a constant energy balance.

    Science.gov (United States)

    Buff, P R; Messer, N T; Cogswell, A M; Johnson, P J; Keisler, D H; Ganjam, V K

    2007-11-01

    The objective of this study was to determine if seasonal and/or pulsatile variations occur in plasma concentrations of thyrotropin (TSH) and leptin in mares while maintaining a constant energy balance. Blood samples were collected every 20 min during a 24h period in winter and again in summer from six Quarter Horse type mares. Plasma concentrations of TSH, leptin, and T(4) were determined by radioimmunoassay. No differences were observed in body weight between winter (388.1+/-12.5 kg) and summer (406.2+/-12.5 kg; P=0.11). Plasma concentrations of TSH were greater in the summer (2.80+/-0.07 ng/ml) when compared to winter (0.97+/-0.07 ng/ml; P<0.001). Pulse frequency of TSH was not different between winter (6.17+/-0.78 pulses/24h) and summer (5.33+/-0.78 pulses/24h; P=0.49). Mean TSH pulse amplitude, pulse area, and area under the curve were all greater in summer compared to winter (3.11+/-0.10 ng/ml versus 1.20+/-0.10 ng/ml, 24.86+/-0.10 ng/ml min versus 13.46+/-1.90 ng/ml min, 3936+/-72.93 ng/ml versus 1284+/-72.93 ng/ml, respectively; P<0.01). Mean concentrations of leptin were greater in summer (2.48+/-0.17 ng/ml) compared to winter (0.65+/-0.17 ng/ml; P<0.001). Pulsatile secretion patterns of leptin were not observed in any horses during experimentation. Mean concentrations of T(4) were greater in winter (20.3+/-0.4 ng/ml) compared to summer (18.2+/-0.4 ng/ml; P<0.001). These seasonal differences between winter and summer provide evidence of possible seasonal regulation of TSH and leptin.

  18. Brain receptors for thyrotropin releasing hormone in morphine tolerant-dependent rats

    Energy Technology Data Exchange (ETDEWEB)

    Bhargava, H.N.; Das, S.

    1986-03-01

    The effect of chronic treatment of rats with morphine and its subsequent withdrawal on the brain receptors for thyrotropin releasing hormone (TRH) labeled with /sup 3/H-(3MeHis/sup 2/)TRH (MeTRH). Male Sprague Dawley rats were implanted with 4 morphine pellets (each containing 75 mg morphine base) during a 3-day period. Placebo pellet implanted rats served as controls. Both tolerance to and dependence on morphine developed as a result of this procedure. For characterization of brain TRH receptors, the animals were sacrificed 72 h after the implantation of first pellet. In another set of animals the pellets were removed and were sacrificed 24 h later. The binding of /sup 3/H-MeTRH to membranes prepared from brain without the cerebellum was determined. /sup 3/H-MeTRH bound to brain membranes prepared from placebo pellet implanted rats at a single high affinity site with a B/sub max/ value of 33.50 +/- 0.97 fmol/mg protein and a K/sub d/ of 5.18 +/- 0.21 nM. Implantation of morphine pellets did not alter the B/sub max/ value of /sup 3/H-MeTRH but decreased the K/sub d/ value significantly. Abrupt or naloxone precipitated withdrawal of morphine did not alter B/sub max/ or the K/sub d/ values. The binding of /sup 3/H-MeTRH to brain areas was also determined. The results suggest that the development of tolerance to morphine is associated with enhanced sensitivity of brain TRH receptors, however abrupt withdrawal of morphine does not change the characteristics of brain TRH receptors.

  19. Thyrotropin - Binding Inhibiting Immunoglobulin (TBII) in Patients with Autoimmune Thyroid Diseases

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Dae Sung; Ahn, Byeong Cheol; Sohn, Sang Kyun; Lee, Jae Tae; Lee, Kyu Bo [Kyungpook National University School of Medicine, Taegu (Korea, Republic of)

    1996-03-15

    In order to evaluate the significance of thyrotropin-binding inhibiting immunoglobulin (TBII) in the patients with autoimmune thyroid diseases, the authors investigated 402 cases of Graves' disease and 230 cases of Hashimoto's thyroiditis comparing 30 cases of normal healthy adult at Kyung Pook University Hospital from February 1993 to August 1994. The TBII was tested by radioimmunoassay and assessed on the dynamic change with the disease course, thyroid functional parameters, and other thyroid autoantibodies; antithyroglobulin antibody(ATAb) and antimicrosomal antibody(AMAb) including thyroglobulin. The serum level of TBII was 40.82 +- 21.651(mean +- SD)% in hyperthyroid Graves' disease and 8.89 +- 14.522% in Hashimoto's thyroiditis and both were significant different from normal control of which was 3.21 +- 2.571%. The frequency of abnormally increased TBII level was 92.2% in hyperthyroid Craves' disease, 46.7% in euthyroid Graves' disease or remission state of hyperthyroidism, and 23.9% in Hashimoto's thyroiditis. The serum levels of increased TBII in Graves' disease were positively correlated with RAIU, serum T3, T4, and FT4, but negatively correlated with serum TSH(each p<0.001). The TBII in Graves' disease had significant positive correlation with serum thyroglobulin and AMAb, but no significant correlation with ATAb. In the Hashimoto's thyroiditis, the serum levels of TBII were positively correlated with RAIU, serum T3, TSH and AMAb, but not significantly correlated with serum T4, FT4, thyroglobulin and ATAb. Therefore serum level of TBII seemed to be a useful mean of assessing the degree of hyperthyroidism in Graves' disease and correlated well with thyroidal stimulation. The serum level of TBII in Hashimoto's thyroiditis is meaningful for the degree of both functional abnormality reflecting either hyperfunction or hypofunction and the immunologic abnormality.

  20. Chronic exposure to hypergravity affects thyrotropin-releasing hormone levels in rat brainstem and cerebellum

    Science.gov (United States)

    Daunton, N. G.; Tang, F.; Corcoran, M. L.; Fox, R. A.; Man, S. Y.

    1998-01-01

    In studies to determine the neurochemical mechanisms underlying adaptation to altered gravity we have investigated changes in neuropeptide levels in brainstem, cerebellum, hypothalamus, striatum, hippocampus, and cerebral cortex by radioimmunoassay. Fourteen days of hypergravity (hyperG) exposure resulted in significant increases in thyrotropin-releasing hormone (TRH) content of brainstem and cerebellum, but no changes in levels of other neuropeptides (beta-endorphin, cholecystokinin, met-enkephalin, somatostatin, and substance P) examined in these areas were found, nor were TRH levels significantly changed in any other brain regions investigated. The increase in TRH in brainstem and cerebellum was not seen in animals exposed only to the rotational component of centrifugation, suggesting that this increase was elicited by the alteration in the gravitational environment. The only other neuropeptide affected by chronic hyperG exposure was met-enkephalin, which was significantly decreased in the cerebral cortex. However, this alteration in met-enkephalin was found in both hyperG and rotation control animals and thus may be due to the rotational rather than the hyperG component of centrifugation. Thus it does not appear as if there is a generalized neuropeptide response to chronic hyperG following 2 weeks of exposure. Rather, there is an increase only of TRH and that occurs only in areas of the brain known to be heavily involved with vestibular inputs and motor control (both voluntary and autonomic). These results suggest that TRH may play a role in adaptation to altered gravity as it does in adaptation to altered vestibular input following labyrinthectomy, and in cerebellar and vestibular control of locomotion, as seen in studies of ataxia.

  1. Elucidation of the electrochromic mechanism of nanostructured iron oxides films

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Lobato, M.A.; Martinez, Arturo I.; Castro-Roman, M. [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav Campus Saltillo, Carr. Saltillo-Monterrey Km. 13, Ramos Arizpe, Coah. 25900 (Mexico); Perry, Dale L. [Mail Stop 70A1150, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Zarate, R.A. [Departamento de Fisica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Escobar-Alarcon, L. (Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico)

    2011-02-15

    Nanostructured hematite thin films were electrochemically cycled in an aqueous solution of LiOH. Through optical, structural, morphological, and magnetic measurements, the coloration mechanism of electrochromic iron oxide thin films was elucidated. The conditions for double or single electrochromic behavior are given in this work. During the electrochemical cycling, it was found that topotactic transformations of hexagonal crystal structures are favored; i.e. {alpha}-Fe{sub 2}O{sub 3} to Fe(OH){sub 2} and subsequently to {delta}-FeOOH. These topotactic redox reactions are responsible for color changes of iron oxide films. (author)

  2. Thyrotropin Receptor Antibody (TRAb)-IgM Levels Are Markedly Higher Than TRAb-IgG Levels in Graves' Disease Patients and Controls, and TRAb-IgM Production Is Related to Epstein-Barr Virus Reactivation.

    Science.gov (United States)

    Kumata, Keisuke; Nagata, Keiko; Matsushita, Michiko; Kuwamoto, Satoshi; Kato, Masako; Murakami, Ichiro; Fukata, Shuji; Hayashi, Kazuhiko

    2016-10-01

    Graves' disease is an autoimmune thyroid disorder that mainly presents as hyperthyroidism and is caused by thyrotropin receptor antibodies (TRAbs) that stimulate thyroid-stimulating hormone receptors. We previously reported that Graves' disease patients and healthy controls both had Epstein-Barr virus (EBV)-infected TRAb-positive B cells and the EBV-reactivated induction of these B cells in cultures may induce the production of TRAbs. In the present study, we quantified serum TRAb-IgG and TRAb-IgM levels in 34 Graves' disease patients and 15 controls using ELISA to elucidate the mechanisms underlying EBV-related antibody production. As expected, TRAb-IgG and TRAb-IgM levels were higher in Graves' disease patients than in controls; however, TRAb-IgM levels were significantly higher than those of TRAb-IgG levels, whereas total IgM levels were lower than total IgG levels. On the other hand, the enhanced production of TRAb-IgM was frequently observed in patients with EBV reactivation. These results are consistent with the fact that the percentage of autoreactive IgM B cells are higher than that of autoreactive IgG B cells, and support the EBV-related polyclonal B cell activation. It is necessary to clarify the biological characteristics of TRAb-IgM and the relationship between TRAb isotypes and the biology of Graves' disease.

  3. Evaluation of enhanced chemiluminescence enzymeimmunoassay(CLEIA) in the determination of thyrotropin(TSH) using amerlite system

    International Nuclear Information System (INIS)

    Lee, Chae H.; Kim, Hwan k.; Kim, Jin Gyu

    1989-01-01

    The determination of thyrotropin(TSH) is useful in diagnosis of thyroid diseases. And the widely-used method for the determination of thyrotropin is radioimmunoassay so far because of its sensitivity. But its radiohazard and relatively short half-life of isotopes necessitates alternative methods. So many novel non-isotopic immunoassays are developed and now replacing RIA in routine laboratory measurements. We evaluated the enhanced chemiluminescence enzymeimmunoassay (Amerlite, Amersham International plc., U.K.) for the determination of serum TSH. We got good precision result with control sera. Within-assay and between-assay precision revealed less than 10%(C.V.) respectively. And comparision with CLEIA to RIA showed good correlation (y=0.648x + 0.170, r=0.978, y=value of CLEIA, x=values of RIA, n=35). We also got good correlation between singletons and duplicates result from 35 patients sera (y=0.967x + 0.0281, r=0.997, y=values of singletons, x=values of duplicates). We concluded that CLEIA is vary reliable and economic method for the determination of human TSH substitutive for RIA because of its precision and unnecessary duplicate measurements. (Author)

  4. Induction of stimulating thyrotropin receptor antibodies after radioiodine therapy for toxic multinodular goitre and Graves' disease measured with a novel bioassay

    NARCIS (Netherlands)

    Hovens, Guido C.; Heemstra, Karen A.; Buiting, Antoinette M. J.; Stokkel, Marcel P.; Karperien, Marcel; Ballieux, Bart E.; Pereira, Alberto M.; Romijn, Johannes A.; Smit, Johannes W.

    2007-01-01

    Radioactive iodine therapy (RaI) in toxic multinodular goitre (TMNG) has been associated with the occurrence of Graves'-like hyperthyroidism. It has been postulated that pre-existing autoimmunity may contribute to this phenomenon. To study whether RaI induces thyrotropin receptor stimulating

  5. Development of an efficient E. coli expression and purification system for a catalytically active, human Cullin3-RINGBox1 protein complex and elucidation of its quaternary structure with Keap1

    International Nuclear Information System (INIS)

    Small, Evan; Eggler, Aimee; Mesecar, Andrew D.

    2010-01-01

    Research highlights: → A novel expression strategy was used to purify Cul3-Rbx1 from E. coli. → The Cul3-Rbx1 complex is fully active and catalyzes ubiquitination of Nrf2 in vitro. → Cul3, Rbx1, and Keap1 form a complex with unique stoichiometry of 1:1:2. -- Abstract: The Cullin3-based E3 ubiquitin ligase complex is thought to play an important role in the cellular response to oxidative stress and xenobiotic assault. While limited biochemical studies of the ligase's role in these complex signaling pathways are beginning to emerge, structural studies are lagging far behind due to the inability to acquire sufficient quantities of full-length, highly pure and active Cullin3. Here we describe the design and construction of an optimized expression and purification system for the full-length, human Cullin3-RINGBox 1 (Rbx1) protein complex from Escherichia coli. The dual-expression system is comprised of codon-optimized Cullin3 and Rbx1 genes co-expressed from a single pET-Duet-1 plasmid. Rapid purification of the Cullin3-Rbx1 complex is achieved in two steps via an affinity column followed by size-exclusion chromatography. Approximately 15 mg of highly pure and active Cullin3-Rbx1 protein from 1 L of E. coli culture can be achieved. Analysis of the quaternary structure of the Cullin3-Rbx1 and Cullin3-Rbx1-Keap1 complexes by size-exclusion chromatography and analytical ultracentrifugation indicates a 1:1 stoichiometry for the Cullin3-Rbx1 complex (MW = 111 kDa), and a 1:1:2 stoichiometry for the Cullin3-Rbx1-Keap1 complex (MW = 280 kDa). This latter complex has a novel quaternary structural organization for cullin E3 ligases, and it is fully active based on an in vitro Cullin3-Rbx1-Keap1-Nrf2 ubiquitination activity assay that was developed and optimized in this study.

  6. Development of an efficient E. coli expression and purification system for a catalytically active, human Cullin3-RINGBox1 protein complex and elucidation of its quaternary structure with Keap1

    Energy Technology Data Exchange (ETDEWEB)

    Small, Evan [Department of Biochemistry, University of Illinois at Chicago, Chicago, IL 60607 (United States); Eggler, Aimee [Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-1971 (United States); Mesecar, Andrew D., E-mail: amesecar@purdue.edu [Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-1971 (United States)

    2010-10-01

    Research highlights: {yields} A novel expression strategy was used to purify Cul3-Rbx1 from E. coli. {yields} The Cul3-Rbx1 complex is fully active and catalyzes ubiquitination of Nrf2 in vitro. {yields} Cul3, Rbx1, and Keap1 form a complex with unique stoichiometry of 1:1:2. -- Abstract: The Cullin3-based E3 ubiquitin ligase complex is thought to play an important role in the cellular response to oxidative stress and xenobiotic assault. While limited biochemical studies of the ligase's role in these complex signaling pathways are beginning to emerge, structural studies are lagging far behind due to the inability to acquire sufficient quantities of full-length, highly pure and active Cullin3. Here we describe the design and construction of an optimized expression and purification system for the full-length, human Cullin3-RINGBox 1 (Rbx1) protein complex from Escherichia coli. The dual-expression system is comprised of codon-optimized Cullin3 and Rbx1 genes co-expressed from a single pET-Duet-1 plasmid. Rapid purification of the Cullin3-Rbx1 complex is achieved in two steps via an affinity column followed by size-exclusion chromatography. Approximately 15 mg of highly pure and active Cullin3-Rbx1 protein from 1 L of E. coli culture can be achieved. Analysis of the quaternary structure of the Cullin3-Rbx1 and Cullin3-Rbx1-Keap1 complexes by size-exclusion chromatography and analytical ultracentrifugation indicates a 1:1 stoichiometry for the Cullin3-Rbx1 complex (MW = 111 kDa), and a 1:1:2 stoichiometry for the Cullin3-Rbx1-Keap1 complex (MW = 280 kDa). This latter complex has a novel quaternary structural organization for cullin E3 ligases, and it is fully active based on an in vitro Cullin3-Rbx1-Keap1-Nrf2 ubiquitination activity assay that was developed and optimized in this study.

  7. Fast and Accurate Identification of Cross-Linked Peptides for the Structural Analysis of Large Protein Complexes and Elucidation of Interaction Networks. / Tahir, Salman; Bukowski-Wills, Jimi-Carlo; Rasmussen, Morten; Rappsilber, Juri

    DEFF Research Database (Denmark)

    Rasmussen, Morten

    to investigate protein structure and protein-protein interactions. When applied to single proteins or small purified protein complexes, this methodology works well. However certain challenges arise when applied to more complex samples. One of the main problems is the combinatorial increase in the search space...... simplify a spectrum because we remove all peaks that are accounted for by the fragmentation of peptide one. This approach is highly sensitive and scales well as revealed by searching our data of synthetic cross-links against a large sequence database. Currently, against a protein database of >1300 proteins...... a spectrum is searched in 0.35 seconds - a vast improvement when compared to the exhaustive search method of combining every potential cross-link for each spectrum(60 hours). In fact the search time is comparable, if not better, than existing linear search engines. Furthermore, we auto-validate the results...

  8. [Thyrotropin reference ranges during pregnancy in the province of Huelva, Spain].

    Science.gov (United States)

    Ortega Carpio, A; Vázquez Rico, I; Castaño López, M A; Duarte González, L; Montilla Álvaro, M; Ruiz Reina, A

    2017-11-18

    The correct diagnosis of hypothyroidism during pregnancy requires knowledge of the local trimester-specific thyrotropin (TSH) reference ranges. When these are not available, the guidelines recommend upper limits of 2.5, 3.0, and 3.0μU/ml for the 1 st , 2 nd , and 3 rd trimesters, respectively. The aim is to establish the reference range for our local population. A population-based observational study was performed on healthy pregnant women from 11 healthcare centres in the province of Huelva. Women were recruited consecutively during 2016 through the pregnancy process. Women were excluded who had a history of thyroid or medical disease, a poor obstetric history, multiple pregnancy, thyroid autoimmunity, and extreme TSH values (10μU/ml), as well as women treated with levothyroxine for thyroid dysfunction. The study included a total of 186 pregnant women, with a mean age of 30.7 years (95% CI: 29.8-31.6) and a body mass index (BMI) of 23.6 (95% CI: 23.2-24.0). Most of them had the first laboratory tests performed before week 11 of pregnancy. Valid subjects for analysis were 145, 105, and 67 pregnant women in the 1 st , 2 nd , and 3 rd trimesters, respectively, after excluding those due to abortion (18.9%), autoimmunity (6.5%), hypo/hyperthyroidism (2.2%), and levothyroxine treatment during the 2 nd /3 rd trimester (18.6%). The 97.5% TSH percentile for the 1 st , 2 nd , and 3 rd trimester was 4.68, 4.83, and 4.57μU/ml, respectively. Thyroid dysfunction was identified in 80 women (55.2%), 33 of whom received treatment with Levothyroxine (22.7%). With the new criteria, thyroid dysfunction prevalence would be reduced to 6.2%, and the need for treatment to 4.1%. The reference range for TSH in our population differs from that proposed by the guidelines. Unnecessary treatment was being given to 18.6% of pregnant women. Copyright © 2017 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Macro- and microadenoma of thyrotropin secreting pituitary tumors--two clinical cases.

    Science.gov (United States)

    Hubalewska-Hola, Alicja; Fröss, Katarzyna; Kostecka-Matyja, Marta; Sowa-Staszczak, Anna; Szybiński, Zbigniew; Huszno, Bohdan; Ptak, Marzena

    2003-01-01

    Thyrotropin secreting adenoma, thyrotropinoma (TSH-oma), is a rare cause of hyperthyroidism--called secondary hyperthyroidism. The hormonal profile in pituitary hyperthyroidism is characterized by a nonsuppressed TSH in the presence of high levels of free thyroid hormones (fT4, fT3) reflecting an abnormal feedback. The diagnosis of TSH-oma is often made at the stage of macroadenoma because of the aggressive nature of the tumor and due to the fact that patients are mistakenly treated for more common primary hyperthyroidism for a long time. Two cases of TSH-secreting adenoma were detected in Chair and Department of Endocrinology, Collegium Medicum of the Jagiellonian University in Krakow for the last twenty years. Case 1: 49 year old woman was admitted to the Clinic of Endocrinology in 1999 with recurring hyperthyroidism treated with surgical thyroid ablation in 1992 and thyreostatics for the previous nine years. On admission to the Clinic her thyroid panel presented with elevated free hormone levels (mainly fT3-14.8 pmol/l) and not suppressed TSH-0.7 mIU/l suggesting central hyperthyroidism. MRI scan of the pituitary gland revealed microadenoma of 5 mm in diameter. She was qualified to transsphenoidal resection of the tumor. Histopathology revealed acidophilic adenoma with positive TSH staining. Thyroid hormones 8 days after the operation suggested full effectiveness of the surgery. Case 2: 65 year old man treated for one year with L-Thyroxin because of elevated TSH (60 mIU/l) and then with thyreostatics for elevated fT3 and fT4 was admitted to the Clinic of Endocrinology in 2000 with suspected thyrotropinoma. On admission to the Clinic thyroid panel suggested hyperthyroidism with fT4-40 pmol/l, FT3-11.2 pmol/l without suppression of TSH 2.2 mIU/l. MRI scan revealed a pituitary tumor 20 x 18 x 20 mm, compressing the optic chiasm. He was administered octreotide as a preparation for the operation. The patient underwent trans-sphenoidal resection of the adenoma

  10. Tetradentate-arm Schiff base derived from the condensation reaction of 3,3′-dihydroxybenzidine, glyoxal/diacetyl and 2-aminophenol: Designing, structural elucidation and properties of their binuclear metal(II complexes

    Directory of Open Access Journals (Sweden)

    E. Akila

    2017-05-01

    Full Text Available The novel binuclear Schiff base complexes were prepared by the reaction of 3,3′-dihydroxybenzidine, glyoxal/diacetyl and 2-aminophenol in 1:2:2 M ratio. The binucleating Schiff base ligand and its complexes of Cu(II, Ni(II and VO(II ions were characterized by elemental analysis, molar conductance, 1H NMR, infrared, electronic spectra, cyclic voltammetry, thermal, magnetic and EPR studies. The low molar conductance values of the complexes support the non-electrolytic in nature. In IR spectra, the comparison of shift in frequency of the complexes with the ligand reveals the coordination of donor atom to the metal atom. The binuclear nature of the complexes is assessed from their magnetic susceptibility values. The electronic and EPR spectra of the metal complexes provide information about the geometry of the complexes and are in good agreement with the proposed square planar geometry for Cu(II, Ni(II and square pyramidal for VO(II complexes. Molecular modeling has been used to suggest the structure of the complexes. The DNA cleavage ability of the complexes was monitored by gel electrophoresis using supercoiled pUC18 DNA. The metal complexes were screened for their antibacterial activities against pathogenic bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Bacillus subtilis. The activity data show that the metal complexes are more potent activity than the parent Schiff base ligand against microorganisms.

  11. Hydrothermal synthesis, structural elucidation, spectroscopic studies, thermal behavior and luminescence properties of a new 3-d compound: FeAlF2(C10H8N2)(HPO4)2(H2O)

    Science.gov (United States)

    Bouzidia, Nabaa; Salah, Najet; Hamdi, Besma; Ben Salah, Abdelhamid

    2017-04-01

    The study of metal phosphate has been a proactive field of research thanks to its applied and scientific importance, especially in terms of the development of optical devices such as solid state lasers as well as optical fibers. The present paper seeks to investigate the synthesis, crystal structure, elemental analysis and properties of FeAlF2(C10H8N2)(HPO4)2(H2O) compound investigated by spectroscopic studies (FT-IR and FT-Raman), thermal behavior and luminescence. The Hirshfeld surface analysis and 2-D fingerprint plot have been performed to explore the behavior of these weak interactions and crystal cohesion. This investigation shows that the molecules are connected by hydrogen bonds of the type Osbnd H⋯O and Osbnd H⋯F. In addition, the 2,2'‒bipyridine ligand plays a significant role in the construction of 3-D supramolecular framework via π‒π stacking. FT‒IR and FT‒Raman spectra were used so as to ease the responsibilities of the vibration modes of the title compound. The thermal analysis (TGA) study shows a mass loss evolution as a temperature function. Finally, the optical properties were evaluated by photoluminescence spectroscopy.

  12. Thyrotropin-releasing hormone (TRH) receptors. Localization by light microscopic autoradiography in rat brain using [3H][3-Me-His2]TRH as the radioligand

    International Nuclear Information System (INIS)

    Mantyh, P.W.; Hunt, S.P.

    1985-01-01

    Thyrotropin releasing hormone (TRH) is a putative neurotransmitter in both the central and peripheral nervous system. In the present report, we have used autoradiography coupled with densitometric analysis of tritium-sensitive film to investigate the distribution of [ 3 H][3-Me-His2]TRH [( 3 H]MeTRH)-binding sizes in the rat brain. Previous pharmacological reports have established that many of these [ 3 H]MeTRH-binding sites have a structure-activity profile consistent with being a physiological TRH receptor. A high level of TRH receptors were observed in the accessory olfactory bulb, lateral nucleus of the amygdala, dentate gyrus, and entorhinal cortex. Moderate levels of TRH receptors were observed in the rhinal cortex, hypothalamus, superior colliculus, several brainstem motor nuclei, and lamina I of the spinal trigeminal nucleus pars candalis, while low concentrations of receptors are present in the cerebral cortex, striatum and ventral horn of the spinal cord. Very low levels of receptors were observed in the globus pallidus and in most nuclei of the dorsal thalamus. Comparisons of the distribution of TRH receptors to TRH-immunoreactive content indicates that, while in some areas of the brain there is a rough correlation between levels of TRH peptide and its receptor, in most brain areas there is little obvious correlation between the two. While such a discrepancy has been observed for other peptides and their receptors, the extensive distribution of TRH receptors in the central nervous system does provide an explanation for the variety of behavioral effects observed when TRH is infused into the central nervous system

  13. Structure elucidation of the O-specific polysaccharide by NMR spectroscopy and selective cleavage and genetic characterization of the O-antigen of Escherichia albertii O5.

    Science.gov (United States)

    Naumenko, Olesya I; Zheng, Han; Wang, Jianping; Senchenkova, Sof'ya N; Wang, Hong; Shashkov, Alexander S; Chizhov, Alexander O; Li, Qun; Knirel, Yuriy A; Xiong, Yanwen

    2018-03-02

    The O-specific polysaccharide (O-antigen) was obtained by mild acid degradation of the lipopolysaccharide of Escherichia albertii O5 (strain T150248) and studied by sugar analysis, selective cleavages of glycosidic linkages, and 1D and 2D 1 H and 13 C NMR spectroscopy. Partial solvolysis with anh (anhydrous) CF 3 CO 2 H and hydrolysis with 0.05 M CF 3 CO 2 H cleaved predominantly the glycosidic linkage of β-GalpNAc or β-Galf, respectively, whereas the linkages of α-GlcpNAc and β-Galp were stable. Mixtures of the corresponding tri- and tetra-saccharides thus obtained were studied by NMR spectroscopy and high-resolution ESI MS. The following new structure was established for the tetrasaccharide repeat (O-unit) of the O-polysaccharide: →4)-α-d-GlcpNAc-(1 → 4)-β-d-Galp6Ac-(1 → 6)-β-d-Galf-(1 → 3)-β-d-GalpNAc-(1→where the degree of O-acetylation of d-Galp is ∼70%. The O-polysaccharide studied has a β-d-Galp-(1 → 6)-β-d-Galf-(1 → 3)-β-d-GalpNAc trisaccharide fragment in common with the O-polysaccharides of E. albertii O7, Escherichia coli O124 and O164, and Shigella dysenteriae type 3 studied earlier. The orf5-7 in the O-antigen gene cluster of E. albertii O5 are 47%, 78%, and 75% identical on the amino acid level to genes for predicted enzymes of E. albertii O7, including Galp-transferase wfeS, UDP-d-Galp mutase glf, and Galf-transferase wfeT, respectively, which are putatively involved with the synthesis of the shared trisaccharide fragment of the O-polysaccharides. The occurrence upstream of the O-antigen gene cluster of a 4-epimerase gene gnu for conversion of undecaprenyl diphosphate-linked d-GlcNAc (UndPP-d-GlcNAc) into UndPP-d-GalNAc indicates that d-GalNAc is the first monosaccharide of the O-unit, and hence the O-units are interlinked in the O-polysaccharide of E. albertii O5 by the β-d-GalpNAc-(1 → 4)-α-d-GlcpNAc linkage. Copyright © 2017. Published by Elsevier Ltd.

  14. Thyrotropin receptor antibody activities significantly correlate with the outcome of radioiodine (131I) therapy for hyperthyroid Graves' disease

    International Nuclear Information System (INIS)

    Kaise, Kazuro; Kaise, Nobuko; Yoshida, Katsumi; Fukazawa, Hiroshi; Mori, Koki; Yamamoto, Makiko; Sakurada, Toshiro; Saito, Shintaro; Yoshinaga, Kaoru

    1991-01-01

    The outcome of 131 I therapy for 109 patients with Graves' disease was analysed according to pretreatment laboratory data including thyrotropin receptor antibody (TRAb) activities. Forty-five percent of patients became euthyroid, and 13% of patients became hypothyroid within one year after 131 I therapy. Forty-two percent of patients remained hyperthyroid one year after 131 I therapy. Pretreatment values for serum T 4 , T 3 , and the estimated weight of the thyroid were significantly higher in the hyperthyroid group. The mean for the TRAb index of the hyperthyroid group was significantly higher than that of the euthyroid group. Life table analysis revealed a significant effect of the TRAb index on the rate of hyperthyroidism after 3 months or later. These results appear to suggest that the TRAb index is one of the factors which influence the outcome of 131 I therapy for Graves' disease. (author)

  15. Basal levels of triiodotironine, thyroxine, thyrotropin, free thyroxine and reverse triiodotyronine in patients with chronic renal failure submitted to hemodialysis

    International Nuclear Information System (INIS)

    Knobel, H.; Mendonca, B.B. de; Mendes, V.; Rocha Junior, J.E.; Medeiros Neto, G.

    1987-01-01

    Serum triiodotironine (T3), thyroxine (T4), thyrotropin (TSH), free thyroxine (FT4) and reverse triiodothyronine (rT3) concentrations were determined by radioimmunoassay in 21 uremic patients on regular hemodialysis therapy (sera were collected immediately before dialysis) and 11 normal controls. In advanced chronic renal failure serum T3 and T4 were frequently decreased (86% and 57%, respectively). and serum rT3 was normal (81%) or subnormal (14%). The serum TSH and FT4 values were normal in all cases even when serum T3 and T4 concentrations were decreased below the normal range. The findings suggest that the measurement of serum TSH probably represents the most reliable differentiation between this disease with low T4 levels and primary hypothyroidism. (author)

  16. Thyrotropin-secreting pituitary tumor presenting with congestive heart failure and good response to dopaminergic agonist cabergoline

    Directory of Open Access Journals (Sweden)

    Yu-Hsi Kao

    2013-11-01

    Full Text Available Hyperthyroidism is an important inducing factor in patients with atrial fibrillation, and may trigger heart failure. Thyrotropin (thyroid stimulating hormone, TSH-secreting pituitary tumors are rare causes of hyperthyroidism. Here, we report a 66-year-old man with a pituitary TSH-secreting tumor who presented with hyperthyroidism and congestive heart failure. Endonasal trans-sphenoidal pituitary adenomectomy was performed. After the operation, the symptoms of hyperthyroidism and congestive heart failure were relieved, associated with normalization of thyroid function tests. Unfortunately, hand tremor and progressively elevated free T4 and TSH concentrations recurred 5 months after surgery. A dopaminergic agonist, cabergoline was administered and euthyroidism was restored for at least 11 months.

  17. Two-monoclonal-antibody sandwich-type assay for thyrotropin, with use of an avidin-biotin separation technique

    International Nuclear Information System (INIS)

    Odell, W.D.; Griffin, J.; Zahradnik, R.

    1986-01-01

    We have developed a sensitive, specific, noncompetitive, sandwich-type radioimmunoassay for human thyrotropin (hTSH), which can be performed in 30 min. The assay involves two monoclonal antibodies, selected for high affinity and specificity and also for reaction against antigenic sites on hTSH that are distal from each other. One of these antibodies is labeled with 125 I; the other is conjugated covalently to biotin. Polystyrene beads were also conjugated covalently to biotin. After conjugation, the beads were incubated with avidin. These beads represent a rapid, simple method for separating hTSH-bound antibody from free antibody. The biotin-antibody-hTSH- 125 I-labeled antibody complexes bind to the beads and hTSH concentration is directly related to counts per minute. This assay can detect hTSH at a concentration of 0.06 milli-unit/L in serum

  18. Elucidating reaction mechanisms on quantum computers

    Science.gov (United States)

    Reiher, Markus; Wiebe, Nathan; Svore, Krysta M.; Wecker, Dave; Troyer, Matthias

    2017-07-01

    With rapid recent advances in quantum technology, we are close to the threshold of quantum devices whose computational powers can exceed those of classical supercomputers. Here, we show that a quantum computer can be used to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical computer simulations used to probe these reaction mechanisms, to significantly increase their accuracy and enable hitherto intractable simulations. Our resource estimates show that, even when taking into account the substantial overhead of quantum error correction, and the need to compile into discrete gate sets, the necessary computations can be performed in reasonable time on small quantum computers. Our results demonstrate that quantum computers will be able to tackle important problems in chemistry without requiring exorbitant resources.

  19. Elucidating reaction mechanisms on quantum computers

    Science.gov (United States)

    Reiher, Markus; Wiebe, Nathan; Svore, Krysta M.; Wecker, Dave; Troyer, Matthias

    2017-01-01

    With rapid recent advances in quantum technology, we are close to the threshold of quantum devices whose computational powers can exceed those of classical supercomputers. Here, we show that a quantum computer can be used to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical computer simulations used to probe these reaction mechanisms, to significantly increase their accuracy and enable hitherto intractable simulations. Our resource estimates show that, even when taking into account the substantial overhead of quantum error correction, and the need to compile into discrete gate sets, the necessary computations can be performed in reasonable time on small quantum computers. Our results demonstrate that quantum computers will be able to tackle important problems in chemistry without requiring exorbitant resources. PMID:28674011

  20. Elucidating reaction mechanisms on quantum computers.

    Science.gov (United States)

    Reiher, Markus; Wiebe, Nathan; Svore, Krysta M; Wecker, Dave; Troyer, Matthias

    2017-07-18

    With rapid recent advances in quantum technology, we are close to the threshold of quantum devices whose computational powers can exceed those of classical supercomputers. Here, we show that a quantum computer can be used to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical computer simulations used to probe these reaction mechanisms, to significantly increase their accuracy and enable hitherto intractable simulations. Our resource estimates show that, even when taking into account the substantial overhead of quantum error correction, and the need to compile into discrete gate sets, the necessary computations can be performed in reasonable time on small quantum computers. Our results demonstrate that quantum computers will be able to tackle important problems in chemistry without requiring exorbitant resources.

  1. Isolation and structural elucidation of compounds from the non ...

    African Journals Online (AJOL)

    CARTA

    Key words: Nicandra physaloides, withanicandrin, β-sitosterol, stigmasterol, antifungal activity. INTRODUCTION .... 30.1 (C-23), 149.8 (C-24), 122.0 (C-25), 167.3. (C-26), 12.7 ( C-27) and .... Glossary of Indian Medicinal Plants. (Including the ...

  2. Free triiodothyronine/free thyroxine ratio rather than thyrotropin is more associated with metabolic parameters in healthy euthyroid adult subjects.

    Science.gov (United States)

    Park, So Young; Park, Se Eun; Jung, Sang Won; Jin, Hyun Seok; Park, Ie Byung; Ahn, Song Vogue; Lee, Sihoon

    2017-07-01

    The interrelation between TSH, thyroid hormones and metabolic parameters is complex and has not been confirmed. This study aimed to determine the association of TSH and thyroid hormones in euthyroid subjects and the relationship between thyroid function and metabolic risk factors. Furthermore, this study examined whether thyroid function has predictive power for metabolic syndrome. This is a cross-sectional study that included subjects in a medical health check-up programme at a single institution. The study included 132 346 participants (66 991 men and 65 355 women) aged over 18 years who had TSH, free T4 (FT4) and free T3 (FT3) levels within the institutional reference ranges. Thyrotropin, FT4, FT3 and metabolic parameters including height, weight, waist circumference, blood pressure, serum levels of total cholesterol, triglyceride, high-density lipoprotein cholesterol, insulin and glucose were measured. There was a positive association between FT3/FT4 ratio and TSH in both men and women after adjusting for age, body mass index, smoking status and menopausal status (in women). The FT3/FT4 ratio and TSH were positively associated with risk of metabolic syndrome parameters including insulin resistance. The FT3/FT4 ratio had a greater predictive power than TSH for metabolic syndrome in both men and women. Thyrotropin levels were positively associated with FT3/FT4 ratio within the euthyroid range. The higher FT3/FT4 ratio is associated with increased risk of metabolic syndrome parameters and insulin resistance. FT3/FT4 ratio has a better predictive power for metabolic syndrome than TSH. © 2017 John Wiley & Sons Ltd.

  3. A thyrotropin-secreting macroadenoma with positive growth hormone and prolactin immunostaining: A case report and literature review.

    Science.gov (United States)

    Kuzu, F; Bayraktaroğlu, T; Zor, F; G N, B D; Salihoğlu, Y S; Kalaycı, M

    2015-01-01

    Thyrotropin (thyroid stimulating hormone [TSH]) secreting pituitary adenomas (TSHoma) are rare adenomas presenting with hyperthyroidism due to impaired negative feedback of thyroid hormone on the pituitary and inappropriate TSH secretion. This article presents a case of TSH-secreting macroadenoma without any clinical hyperthyroidism symptoms accompanying immunoreaction with growth hormone (GH) and prolactin. A 36-year-old female patient was admitted with complaints of irregular menses and blurred vision. On physical exam, she had bitemporal hemianopsia defect. Magnetic resonance imaging (MRI) evaluation showed suprasellar macroadenoma measuring 33 mm × 26 mm × 28 mm was detected on pituitary MRI. She had no hyperthyroidism symptoms clinically. Although free T4 and free T3 levels were elevated, TSH level was inappropriately within the upper limit of normal. Response to T3 suppression and thyrotropin releasing hormone-stimulation test was inadequate. Other pituitary hormones were normal. Transsphenoidal adenomectomy was performed due to parasellar compression findings. Immunohistochemically widespread reaction was observed with TSH, GH and prolactin in the adenoma. The patient underwent a second surgical procedure 2 months later due to macroscopic residual tumor, bitemporal hemianopsia and a suprasellar homogenous uptake with regular borders on indium-111 octreotide scintigraphy. After second surgery; due to ongoing symptoms and residual tumor, she was managed with octreotide and cabergoline treatment. On her follow-up with medical treatment, TSH and free T4 values were within normal limits. Although silent TSHomas are rare, they may arise with compression symptoms as in our case. The differential diagnosis of secondary hyperthyroidism should include TSHomas and thyroid hormone receptor resistance syndrome.

  4. Elucidation of the mechanism for anomalous blueshift

    International Nuclear Information System (INIS)

    Kotaki, Hideyuki; Kando, Masaki; Koga, J.K.; Nakajima, Kazuhisa

    2004-01-01

    The anomalous blue shift of high intensity laser which was discovered by the present authors occurs in the process of gas ionization accompanied with the self-focusing. This shift does not depend either on the laser power or on the gas density and all photons are shifted by a certain frequency, while the one which has been known in common depends on both the intensity and density and only some part of the laser photons is shifted. In order to elucidate this phenomenon, the occurrence conditions of the anomalous blue shift were investigated and the results are compared with theory. The shifts were measured by focusing the laser beam in the gas-filled chamber with an off-axis-parabolic mirror and with a convex lens. When the reflective lens was used the amount of the shift depended significantly on the ionization rate of the plasma, while it depended on the pulse width when the transmission lens was used indicating that the shift is determined by the valence due to the ionization at the focusing point. (S. Funahashi)

  5. Biochemical research elucidating metabolic pathways in Pneumocystis*

    Directory of Open Access Journals (Sweden)

    Kaneshiro E.S.

    2010-12-01

    Full Text Available Advances in sequencing the Pneumocystis carinii genome have helped identify potential metabolic pathways operative in the organism. Also, data from characterizing the biochemical and physiological nature of these organisms now allow elucidation of metabolic pathways as well as pose new challenges and questions that require additional experiments. These experiments are being performed despite the difficulty in doing experiments directly on this pathogen that has yet to be subcultured indefinitely and produce mass numbers of cells in vitro. This article reviews biochemical approaches that have provided insights into several Pneumocystis metabolic pathways. It focuses on 1 S-adenosyl-L-methionine (AdoMet; SAM, which is a ubiquitous participant in numerous cellular reactions; 2 sterols: focusing on oxidosqualene cyclase that forms lanosterol in P. carinii; SAM:sterol C-24 methyltransferase that adds methyl groups at the C-24 position of the sterol side chain; and sterol 14α-demethylase that removes a methyl group at the C-14 position of the sterol nucleus; and 3 synthesis of ubiquinone homologs, which play a pivotal role in mitochondrial inner membrane and other cellular membrane electron transport.

  6. Stimulation with 0.3-mg recombinant human thyrotropin prior to iodine 131 therapy to improve the size reduction of benign nontoxic nodular goiter

    DEFF Research Database (Denmark)

    Nielsen, Viveque Egsgaard; Bonnema, Steen Joop; Boel-Jørgensen, Henrik

    2006-01-01

    measurements of thyroid size and function and patient satisfaction. RESULTS: Baseline median goiter volume was 51 mL (range, 20-99 mL) in the placebo group and 59 mL (range, 25-92 mL) in the thyrotropin group (P = .75). At 12 months, the mean +/- SEM relative goiter reduction was 46.1% +/- 4.0% in the placebo...

  7. Protein alterations induced by long-term agonist treatment of HEK293 cells expressing thyrotropin-releasing hormone receptor and G11alpha protein

    Czech Academy of Sciences Publication Activity Database

    Drastichová, Z.; Bouřová, Lenka; Hejnová, L.; Jedelský, P.; Svoboda, Petr; Novotný, J.

    2010-01-01

    Roč. 109, č. 1 (2010), s. 255-264 ISSN 0730-2312 R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA309/06/0121; GA ČR(CZ) GD305/08/H037 Institutional research plan: CEZ:AV0Z50110509 Keywords : Thyrotropin-releasing hormone * Gq/11 protein * proteomics Subject RIV: ED - Physiology Impact factor: 3.122, year: 2010

  8. Dose-dependent effects of 17-ß-estradiol on pituitary thyrotropin content and secretion in vitro

    Directory of Open Access Journals (Sweden)

    Moreira R.M.

    1997-01-01

    Full Text Available We studied the basal and thyrotropin-releasing hormone (TRH (50 nM induced thyrotropin (TSH release in isolated hemipituitaries of ovariectomized rats treated with near-physiological or high doses of 17-ß-estradiol benzoate (EB; sc, daily for 10 days or with vehicle (untreated control rats, OVX. One group was sham-operated (normal control. The anterior pituitary glands were incubated in Krebs-Ringer bicarbonate medium, pH 7.4, at 37oC in an atmosphere of 95% O2/5% CO2. Medium and pituitary TSH was measured by specific RIA (NIDDK-RP-3. Ovariectomy induced a decrease (P<0.05 in basal TSH release (normal control = 44.1 ± 7.2; OVX = 14.7 ± 3.0 ng/ml and tended to reduce TRH-stimulated TSH release (normal control = 33.0 ± 8.1; OVX = 16.6 ± 2.4 ng/ml. The lowest dose of EB (0.7 µg/100 g body weight did not reverse this alteration, but markedly increased the pituitary TSH content (0.6 ± 0.06 µg/hemipituitary; P<0.05 above that of OVX (0.4 ± 0.03 µg/hemipituitary and normal rats (0.46 ± 0.03 µg/hemipituitary. The intermediate EB dose (1.4 µg/100 g body weight induced a nonsignificant tendency to a higher TSH response to TRH compared to OVX and a lower response compared to normal rats. Conversely, in the rats treated with the highest dose (14 µg/100 g body weight, serum 17-ß-estradiol was 17 times higher than normal, and the basal and TRH-stimulated TSH release, as well as the pituitary TSH content, was significantly (P<0.05 reduced compared to normal rats and tended to be even lower than the values observed for the vehicle-treated OVX group, suggesting an inhibitory effect of hyperestrogenism. In conclusion, while reinforcing the concept of a positive physiological regulatory role of estradiol on the TSH response to TRH and on the pituitary stores of the hormone, the present results suggest an inhibitory effect of high levels of estrogen on these responses

  9. Recombinant human thyrotropin stimulation prior to 131I therapy in toxic multinodular goitre with low radioactive iodine uptake.

    Science.gov (United States)

    Azorín Belda, M J; Martínez Caballero, A; Figueroa Ardila, G C; Martínez Ramírez, M; Gómez Jaramillo, C A; Dolado Ardit, J I; Verdú Rico, J

    Stimulation with recombinant human thyrotropin (rhTSH) increases thyroid radioiodine uptake, and is an aid to 131 I therapy in non-toxic multinodular goitre (MNG). However, there are not many studies using rhTSH prior to 131 I in toxic multinodular goitre to improve hyperthyroidism and compressive symptoms. A prospective study was conducted on patients with MNG and hyperthyroidism. Patients were recruited consecutively and divided into group I, stimulated with 0.3mg of rhTSH before radioiodine therapy, and a control group or group II, without stimulation. Thyroid function, radioiodine thyroid uptake, thyroid weight, and compressive symptoms were measured, and patients were followed-up for 9 months. Group I consisted of 16 patients (14 women), with a mean age 69.7 years, and group II with 16 patients (12 women), with a mean age 70.7 years. After stimulation with 0.3mg rhTSH in group I, 131 I uptake (RAIU) at 24h increased by 78.4%, and the estimated absorbed dose by 89.3%. In group II, the estimated absorbed dose was lower than group I after stimulation with rhTSH (29.8Gy vs. 56.4Gy; P=0.001). At 9 months of follow-up, hyperthyroidism was controlled in 87.5% of patients in group I, and 56.2% in group II (P=0.049). The mean reduction in thyroid weight was higher in group I than in group II (39.3% vs. 26.9%; P=0.017), with a tendency towards subjective improvement of compressive symptoms in group I, although non-significant. Only 2 patients described tachycardias after rhTSH administration, which were resolved with beta-blockers. Stimulation with 0.3mg of recombinant human thyrotropin prior to radioiodine therapy achieves a reduction in thyroid weight and functional improvement in patients with hyperthyroidism and multinodular goitre with low uptake, and with no need for hospital admission. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  10. PET Study in a Patient with Spinocerebellar Degeneration before and after Long-Term Administration of Thyrotropin Releasing Hormone

    Directory of Open Access Journals (Sweden)

    H. Tanji

    1996-01-01

    Full Text Available We studied the chronic effect of thyrotropin releasing hormone (TRH in a patient with spinocerebellar degeneration by measuring cerebral metabolic rate for glucose (CMRG1c using 2-[18F]fluoro-2-deoxy-D-glucose (18FDG and positron emission tomography (PET. A 56-year-old female, who had suffered from progressive ataxia for 2 years, was treated by intravenous administration of 2 mg TRH for 3 weeks, and CMRG1c of the brain was measured before and after treatment. CMRG1c was markedly decreased in the cerebellum and there was no significant difference before and after the treatment, i.e. mean CMRG1c values were 4.92 and 4.90 mg/100 g/min, and the ratios of the cerebellum versus the frontal cortex were 0.50 and 0.51, respectively. The degree of disequilibrium of her body examined with stabilography became better by the 19th day and further improved by the 26th day after the start of TRH treatment. Based on the present study we conclude that long-term administration of TRH did not improve CMRG1c in the cerebellum, but evidently improved the sway of gravity center by stabilography. We speculate that the chronic effect of TRH was not necessarily due to an improvement of cerebellar function, because TRH receptors are widely distributed throughout the central nervous system.

  11. The negative correlation between thyrotropin receptor-stimulating antibodies and bone mineral density in postmenopausal patients with Graves' disease.

    Science.gov (United States)

    Amashukeli, Medea; Korinteli, Maka; Zerekidze, Tamar; Jikurauli, Nino; Shanava, Shorena; Tsagareli, Marina; Giorgadze, Elen

    2013-06-01

    Graves' disease is an autoimmune disorder with various clinical manifestations. Thyrotropin receptor antibodies (TRAbs), the circulating autoantibodies specific to Graves' disease, are the cause for hyperthyroidism, the most prevalent abnormality. Hyperthyroidism leads to increased bone turnover and a negative bone balance. The aims of the present study were to determine the relationship between TRAbs and bone mineral density (BMD), to assess the extent of BMD change in patients with Graves' disease, and to determine the impact of conservative and surgical therapy on BMD. Fifty female postmenopausal patients with Graves' disease were chosen for this study. Twenty women had a recent diagnosis of Graves' disease, 30 women presented with a compensated disease state after either conservative or surgical treatment, and 30 healthy postmenopausal women served as controls. Thyroid parameters were measured, and BMD values were obtained by dual energy x-ray absorptiometry scan.Femoral neck and lumbar spine BMD and T-scores were significantly lower in newly diagnosed patients compared with the control group, but a difference was not observed between the treated and control groups. Statistical analysis revealed a strong and significant negative correlation between femoral neck and lumbar spine BMD and TRAb values.Both surgical and conservative therapies are effective for restoring BMD in postmenopausal patients with Graves' disease, and the increased level of TRAb can be a useful marker of bone density impairment.

  12. The study on mutations of the gene of extracellular domain of human thyrotropin receptor in the patients with thyroid diseases

    International Nuclear Information System (INIS)

    Zhang Zuncheng; Fang Peihua; Tan Jian; Lu Mei

    2002-01-01

    Objective: To define the sequence of the gene of extracellular domain of normal human thyrotropin receptor (hTSHR) and to investigate the mutations of the gene in the patients with thyroid diseases. Methods: Total RNAs were extracted from the thyroid tissue of four normal controls, twelve Graves' disease, four Hashimoto's thyroiditis and eleven nodular goiter patients. The extracellular domain of hTSHR genes were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and sequenced with CEQ 2000 Genetic Analyzer. Results: The normal controls and the patients with thyroid disease had the same gene sequences of the extracellular domain of hTSHR. No mutation was found, except a silent base exchange in exon 7 (Asn187) at 661 base, in which 20 samples were 'T', 11 samples were 'C', without changes of amino acid of the TSHR. Conclusions: This study has not revealed mutations in the gene of extracellular domain of hTSHR. Other molecular pathogenetic mechanisms may be involved and more research is demanded

  13. Two novel mutations in the sixth transmembrane segment of the thyrotropin receptor gene causing hyperfunctioning thyroid nodules.

    Science.gov (United States)

    Gozu, Hulya; Avsar, Melike; Bircan, Rifat; Claus, Maren; Sahin, Serap; Sezgin, Ozlem; Deyneli, Oguzhan; Paschke, Ralf; Cirakoglu, Beyazit; Akalin, Sema

    2005-04-01

    Autonomously functioning thyroid nodules (AFTNs) can present as hyperfunctioning adenomas or toxic multinodular goiters. In the last decade, a large number of activating mutations have been identified in the thyrotropin receptor (TSHR) gene in autonomously functioning thyroid nodules. Most have been situated close to, or within the sixth transmembrane segment and third intracellular loop of the TSHR where the receptor interacts with the Gs protein. In this study we describe two novel mutations in the sixth transmembrane segment of the TSHR causing hyperfunctioning thyroid nodules. Genomic DNAs were isolated from four hyperfunctioning thyroid nodules, normal tissues and peripheral leukocytes of two patients with toxic multinodular goiter. After amplifying the related regions, TSHR and G(s)alpha genes were analyzed by single-strand conformation polymorphism (SSCP) analysis. The precise localization of the mutations was identified by automatic DNA sequence analysis. Functional studies were done by site-directed mutagenesis and transfection of a mutant construct into COS-7 cells. We identified two novel TSHR mutations in two hyperfunctioning thyroid nodules: Phe631Val in the first patient and Iso630Met in the second patient. Both mutant receptors display an increase in constitutive stimulation of basal cyclic adenosine monophosphate (cAMP) levels compared to the wild-type receptor. This confirms that these mutant receptors cause hyperfunctioning thyroid nodules.

  14. Novel germline mutation (Leu512Met) in the thyrotropin receptor gene (TSHR) leading to sporadic non-autoimmune hyperthyroidism.

    Science.gov (United States)

    Roberts, Stephanie A; Moon, Jennifer E; Dauber, Andrew; Smith, Jessica R

    2017-03-01

    Primary nonautoimmune hyperthyroidism is a rare cause of neonatal hyperthyroidism. This results from an activating mutation in the thyrotropin-receptor (TSHR). It can be inherited in an autosomal dominant manner or occur sporadically as a de novo mutation. Affected individuals display a wide phenotype from severe neonatal to mild subclinical hyperthyroidism. We describe a 6-month-old boy with a de novo mutation in the TSHR gene who presented with accelerated growth, enlarging head circumference, tremor and thyrotoxicosis. Genomic DNA from the patient's and parents' peripheral blood leukocytes was extracted. Exons 9 and 10 of the TSHR gene were amplified by PCR and sequenced. Sequencing exon 10 of the TSHR gene revealed a novel heterozygous missense mutation substituting cytosine to adenine at nucleotide position 1534 in the patient's peripheral blood leukocytes. This leads to a substitution of leucine to methionine at amino acid position 512. The mutation was absent in the parents. In silico modeling by PolyPhen-2 and SIFT predicted the mutation to be deleterious. The p.Leu512Met mutation (c.1534C>A) of the TSHR gene has not been previously described in germline or somatic mutations. This case presentation highlights the possibility of mild thyrotoxicosis in affected individuals and contributes to the understanding of sporadic non-autoimmune primary hyperthyroidism.

  15. Novel germline mutation (Leu512Met) in the thyrotropin receptor gene (TSHR) leading to sporadic non-autoimmune hyperthyroidism

    Science.gov (United States)

    Roberts, Stephanie A.; Moon, Jennifer E.; Dauber, Andrew; Smith, Jessica R.

    2018-01-01

    Background Primary nonautoimmune hyperthyroidism is a rare cause of neonatal hyperthyroidism. This results from an activating mutation in the thyrotropin-receptor (TSHR). It can be inherited in an autosomal dominant manner or occur sporadically as a de novo mutation. Affected individuals display a wide phenotype from severe neonatal to mild subclinical hyperthyroidism. We describe a 6-month-old boy with a de novo mutation in the TSHR gene who presented with accelerated growth, enlarging head circumference, tremor and thyrotoxicosis. Methods Genomic DNA from the patient’s and parents’ peripheral blood leukocytes was extracted. Exons 9 and 10 of the TSHR gene were amplified by PCR and sequenced. Results Sequencing exon 10 of the TSHR gene revealed a novel heterozygous missense mutation substituting cytosine to adenine at nucleotide position 1534 in the patient’s peripheral blood leukocytes. This leads to a substitution of leucine to methionine at amino acid position 512. The mutation was absent in the parents. In silico modeling by PolyPhen-2 and SIFT predicted the mutation to be deleterious. Conclusions The p.Leu512Met mutation (c.l534C>A) of the TSHR gene has not been previously described in germline or somatic mutations. This case presentation highlights the possibility of mild thyrotoxicosis in affected individuals and contributes to the understanding of sporadic non-autoimmune primary hyperthyroidism. PMID:28195550

  16. An inverse approach for elucidating dendritic function

    Directory of Open Access Journals (Sweden)

    Benjamin Torben-Nielsen

    2010-09-01

    Full Text Available We outline an inverse approach for investigating dendritic function-structure relationships by optimizing dendritic trees for a-priori chosen computational functions. The inverse approach can be applied in two different ways. First, we can use it as a `hypothesis generator' in which we optimize dendrites for a function of general interest. The optimization yields an artificial dendrite that is subsequently compared to real neurons. This comparison potentially allows us to propose hypotheses about the function of real neurons. In this way, we investigated dendrites that optimally perform input-order detection. Second, we can use it as a `function confirmation' by optimizing dendrites for functions hypothesized to be performed by classes of neurons. If the optimized, artificial, dendrites resemble the dendrites of real neurons the artificial dendrites corroborate the hypothesized function of the real neuron. Moreover, properties of the artificial dendrites can lead to predictions about yet unmeasured properties. In this way, we investigated wide-field motion integration performed by the VS cells of the fly visual system. In outlining the inverse approach and two applications, we also elaborate on the nature of dendritic function. We furthermore discuss the role of optimality in assigning functions to dendrites and point out interesting future directions.

  17. Building blocks for automated elucidation of metabolites: natural product-likeness for candidate ranking.

    Science.gov (United States)

    Jayaseelan, Kalai Vanii; Steinbeck, Christoph

    2014-07-05

    In metabolomics experiments, spectral fingerprints of metabolites with no known structural identity are detected routinely. Computer-assisted structure elucidation (CASE) has been used to determine the structural identities of unknown compounds. It is generally accepted that a single 1D NMR spectrum or mass spectrum is usually not sufficient to establish the identity of a hitherto unknown compound. When a suite of spectra from 1D and 2D NMR experiments supplemented with a molecular formula are available, the successful elucidation of the chemical structure for candidates with up to 30 heavy atoms has been reported previously by one of the authors. In high-throughput metabolomics, usually 1D NMR or mass spectrometry experiments alone are conducted for rapid analysis of samples. This method subsequently requires that the spectral patterns are analyzed automatically to quickly identify known and unknown structures. In this study, we investigated whether additional existing knowledge, such as the fact that the unknown compound is a natural product, can be used to improve the ranking of the correct structure in the result list after the structure elucidation process. To identify unknowns using as little spectroscopic information as possible, we implemented an evolutionary algorithm-based CASE mechanism to elucidate candidates in a fully automated fashion, with input of the molecular formula and 13C NMR spectrum of the isolated compound. We also tested how filters like natural product-likeness, a measure that calculates the similarity of the compounds to known natural product space, might enhance the performance and quality of the structure elucidation. The evolutionary algorithm is implemented within the SENECA package for CASE reported previously, and is available for free download under artistic license at http://sourceforge.net/projects/seneca/. The natural product-likeness calculator is incorporated as a plugin within SENECA and is available as a GUI client and

  18. Thyrotropin levels are associated with chronic kidney disease among healthy subjects in cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

    Science.gov (United States)

    Peixoto de Miranda, Érique José F; Bittencourt, Márcio Sommer; Goulart, Alessandra C; Santos, Itamar S; de Oliveira Titan, Silvia Maria; Ladeira, Roberto Marini; Barreto, Sandhi Maria; Lotufo, Paulo A; Benseñor, Isabela Judith Martins

    2017-12-01

    Few studies have evaluated a possible relationship between thyrotropin levels and glomerular filtration rate (GFR) and albumin/creatinine ratio in euthyroid subjects. We aimed to analyze this association using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Cross-sectionally, we included subjects with normal thyroid function and with subclinical hypothyroidism (SCH). We excluded individuals using medications that affect thyroid function. Linear and logistic regression models evaluated GFR estimated by Chronic Kidney Disease Epidemiology Collaboration (CKD-Epi) and albuminuria/creatinine ratio as dependent variables and thyrotropin quartiles in individuals with euthyroidism and SCH as independent variables, adjusted for demographical characteristics and diseases related to CKD. We included 13,193 subjects with a median age of 51 years [interquartile range, (IQR): 45-58], 6840 (51.8%) women, 12,416 (94.1%) euthyroid, and 777 (5.9%) with SCH. SCH subjects were characterized by higher age, triglycerides, frequency of white race, cardiovascular disease, CKD, and former smokers. In adjusted models, log-transformed TSH in euthyroid subjects was inversely and strongly associated with CKD (β = -2.181, 95% CI -2.714 to -1.648), P < 0.0001 for glomerular filtration rate and 4.528 (1.190-7.865) for albuminuria/creatinine ratio. Multivariate logistic models for euthyroid subjects showed an OR of 1.45 (95% CI 1.15-1.83) for GFR and of 1.95 (95% CI 1.08-3.54) for albuminuria/creatinine ratio in the fourth quartile of TSH using the first as the reference. Thyrotropin levels are independently associated with CKD in euthyroid subjects.

  19. A Placebo-Controlled, Blinded and Randomised Study on the Effects of Recombinant Human Thyrotropin on Quality of Life in the Treatment of Thyroid Cancer

    DEFF Research Database (Denmark)

    Nygaard, Birte; Bastholt, Lars; Bennedbæk, Finn Noe

    2013-01-01

    BACKGROUND: It is well known that thyroid hormone withdrawal (THW) in thyroid cancer patients can induce a decrease in quality of life (QOL). Recombinant human thyrotropin (rh-TSH) has been used to avoid this; however, no blinded studies have ever documented the effect. OBJECTIVE: To compare QOL...... in patients with differentiated thyroid cancer (DTC) treated with either rh-TSH or liothyronine (L-T3) THW for 10 days. STUDY DESIGN: Double-blind, randomised cross-over. PATIENTS: Fifty-six patients with DTC treated by total thyroidectomy and indication for postsurgery radioiodine (RI) ablation therapy...

  20. Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin

    DEFF Research Database (Denmark)

    Dolva, L O; Welinder, B S; Hanssen, K F

    1983-01-01

    Thyrotropin-releasing hormone immunoreactivity (TRH-IR) was measured in isolated islets and in medium from rat pancreatic islets maintained in organ culture. TRH-IR in methanol extracts of both islets and culture medium was eluted in the same position as synthetic TRH by ion-exchange and gel...... chromatography and exhibited dilution curves parallel with synthetic TRH in radioimmunoassay. [3H]Histidine was incorporated into a component that reacted with TRH antiserum and had the same retention time as synthetic TRH on reversed-phase high-performance liquid chromatography. A continuous release of TRH...

  1. Thyrotropin regulates IL-6 expression in CD34+ fibrocytes: clear delineation of its cAMP-independent actions.

    Directory of Open Access Journals (Sweden)

    Nupur Raychaudhuri

    Full Text Available IL-6 plays diverse roles in normal and disease-associated immunity such as that associated with Graves' disease (GD. In that syndrome, the orbit undergoes remodeling during a process known as thyroid-associated ophthalmopathy (TAO. Recently, CD34(+ fibrocytes were found to infiltrate the orbit in TAO where they transition into CD34(+ orbital fibroblasts. Surprisingly, fibrocytes display high levels of functional thyrotropin receptor (TSHR, the central antigen in GD. We report here that TSH and the pathogenic anti-TSHR antibodies that drive hyperthyroidism in GD induce IL-6 expression in fibrocytes and orbital fibroblasts. Unlike TSHR signaling in thyroid epithelium, that occurring in fibrocytes is completely independent of adenylate cyclase activation and cAMP generation. Instead TSH activates PDK1 and both AKT/PKB and PKC pathways. Expression and use of PKCβII switches to that of PKCµ as fibrocytes transition to TAO orbital fibroblasts. This shift is imposed by CD34(- orbital fibroblasts but reverts when CD34(+ fibroblasts are isolated. The up-regulation of IL-6 by TSH results from coordinately enhanced IL-6 gene promoter activity and increased IL-6 mRNA stability. TSH-dependent IL-6 expression requires activity at both CREB (-213 to -208 nt and NF-κB (-78 to -62 nt binding sites. These results provide novel insights into the molecular action of TSH and signaling downstream for TSHR in non-thyroid cells. Fibrocytes neither express adenylate cyclase nor generate cAMP and thus these findings are free from any influence of cAMP-related signaling. They identify potential therapeutic targets for TAO.

  2. Anti-thyrotropin receptor antibody levels after radioiodine therapy in patients of childbearing age with Graves' disease

    International Nuclear Information System (INIS)

    Takeuchi, Mizuho; Tojo, Katsuyoshi; Tajima, Naoko; Yoshimura, Hiroshi; Ito, Koichi

    2006-01-01

    Following radioiodine therapy for Graves' disease, transient elevation of anti-thyrotropin receptor antibody (TRAb) is observed. Elevation of TRAb causes neonatal hyperthyroidism. Serum TRAb levels before radioiodine therapy, 2 months to 1 year, 1 to 2 years, 2 to 3 years, and 3 to 4 years after radioiodine therapy were retrospectively analyzed in 25 women of childbearing age with Graves' disease. The normal range for TRAb is ≤15%. The one patient with serum TRAb levels <10% before radioiodine therapy did not have TRAb levels ≥50% after radioiodine therapy. However, in patients with serum TRAb levels of 10% to 30% before radioiodine therapy (n=8), TRAb were ≥50% in 75.0% 2 months to 1 year after radioiodine therapy, in 25.0% 1 to 2 years after, and in 37.5% 2 to 4 years after. In patients with serum TRAb levels of 30% to 50% before radioiodine therapy (n=3), TRAb levels were ≥50% in 33.3% 2 months to 1 year after radioiodine therapy and in 0.0% 1 to 4 years after. In patients with serum TRAb levels of 50% to 70% before radioiodine therapy (n=6), TRAb were ≥50% in 83.3% 2 months to 1 year after radioiodine therapy, in 66.6% 1 to 2 years after, and in 33.3% 2 to 4 years after. In patients with serum TRAb levels ≥70% before radioiodine therapy (n=7), TRAb levels were ≥50% in 100% 2 months to 1 year after radioiodine therapy, in 85.7% 1 to 2 years after, in 71.4% 2 to 3 years after, and in 57.1% 3 to 4 years after. Serum TRAb levels are more likely to be ≥50% after radioiodine therapy in patients with high serum TRAb levels before radioiodine therapy. (author)

  3. Thyrotropin Suppressive Therapy for Low-Risk Small Thyroid Cancer: A Propensity Score-Matched Cohort Study.

    Science.gov (United States)

    Park, Suyeon; Kim, Won Gu; Han, Minkyu; Jeon, Min Ji; Kwon, Hyemi; Kim, Mijin; Sung, Tae-Yon; Kim, Tae Yong; Kim, Won Bae; Hong, Suck Joon; Shong, Young Kee

    2017-09-01

    Thyrotropin (TSH) suppression has improved the clinical outcomes of patients with differentiated thyroid cancer (DTC). However, the efficacy of TSH suppressive therapy (TST) is unclear in patients with low-risk DTC. This study aimed to evaluate the efficacy of TST and optimal TSH levels of patients with low-risk DTC. This retrospective propensity score-matched cohort study included DTC patients (n = 446) who underwent lobectomy from 2002 to 2008 with or without TST (TST group and No-TST group). Disease-free survival (DFS) and dynamic risk stratification were compared between both groups using serum TSH levels. Approximately 74% of TST patients and 11% of No-TST patients had suppressed serum TSH levels (<2 mIU/L). The median follow-up period was 8.6 years. During follow-up, the disease recurred in 10 (2.7%) patients, with no significant difference in DFS between the groups (p = 0.63). The proportion of patients with excellent treatment response was similar between the TST (65.2%) and No-TST (64.4%) groups. Incomplete biochemical response was noted in 17.2% of the TST group patients and 9.4% of the No-TST group patients. No significant difference was observed in the DFS between both groups by comparing serum TSH level (p = 0.57). TST did not improve clinical outcomes, and serum TSH levels were not associated with recurrence in patients with low-risk small DTC. No clinical benefits were shown for TSH suppression in low-risk patients who underwent lobectomy. Thus, levothyroxine is not necessary for patients without evidence of hypothyroidism.

  4. Mediator subunit MED1 is a T3-dependent and T3-independent coactivator on the thyrotropin β gene promoter

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Keiji; Oda, Kasumi; Mizuta, Shumpei; Ishino, Ruri; Urahama, Norinaga; Hasegawa, Natsumi [Laboratory of Hematology, Division of Medical Biophysics, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142 (Japan); Roeder, Robert G. [Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States); Ito, Mitsuhiro, E-mail: itomi@med.kobe-u.ac.jp [Laboratory of Hematology, Division of Medical Biophysics, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142 (Japan); Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States); Department of Family and Community Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 654-0142 (Japan); Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 159-8555 (Japan)

    2013-10-11

    Highlights: •MED1 is a bona fide T3-dependent coactivator on TSHB promoter. •Mice with LxxLL-mutant MED1 have attenuated TSHβ mRNA and thyroid hormone levels. •MED1 activates TSHB promoter T3-dependently in cultured cells. •T3-dependent MED1 action is enhanced when SRC1/SRC2 or HDAC2 is downregulated. •MED1 is also a T3-independent GATA2/Pit1 coactivator on TSHB promoter. -- Abstract: The MED1 subunit of the Mediator transcriptional coregulator complex is a nuclear receptor-specific coactivator. A negative feedback mechanism of thyroid-stimulating hormone (TSH, or thyrotropin) expression in the thyrotroph in the presence of triiodothyronine (T3) is employed by liganded thyroid hormone receptor β (TRβ) on the TSHβ gene promoter, where conventional histone-modifying coactivators act as corepressors. We now provide evidence that MED1 is a ligand-dependent positive cofactor on this promoter. TSHβ gene transcription was attenuated in MED1 mutant mice in which the nuclear receptor-binding ability of MED1 was specifically disrupted. MED1 stimulated GATA2- and Pit1-mediated TSHβ gene promoter activity in a ligand-independent manner in cultured cells. MED1 also stimulated transcription from the TSHβ gene promoter in a T3-dependent manner. The transcription was further enhanced when the T3-dependent corepressors SRC1, SRC2, and HDAC2 were downregulated. Hence, MED1 is a T3-dependent and -independent coactivator on the TSHβ gene promoter.

  5. Hyperthyroidism caused by a germline activating mutation of the thyrotropin receptor gene: difficulties in diagnosis and therapy.

    Science.gov (United States)

    Bertalan, Rita; Sallai, Agnes; Sólyom, János; Lotz, Gábor; Szabó, István; Kovács, Balázs; Szabó, Eva; Patócs, Attila; Rácz, Károly

    2010-03-01

    Germline activating mutations of the thyrotropin receptor (TSHR) gene have been considered as the only known cause of sporadic nonautoimmune hyperthyroidism in the pediatric population. Here we describe the long-term follow-up and evaluation of a patient with sporadic nonautoimmune primary hyperthyroidism who was found to have a de novo germline activating mutation of the TSHR gene. The patient was an infant who presented at the age of 10 months in an unconscious state with exsiccation, wet skin, fever, and tachycardia. Nonautoimmune primary hyperthyroidism was diagnosed, and brain magnetic resonance imaging and computed tomography showed also Arnold-Chiari malformation type I. Continuous propylthiouracil treatment resulted in a prolonged clinical cure lasting for 10 years. At the age of 11 years and 5 months the patient underwent subtotal thyroidectomy because of symptoms of trachea compression caused by a progressive multinodular goiter. However, 2 months after surgery, hormonal evaluation indicated recurrent hyperthyroidism and the patient was treated with propylthiouracil during the next 4 years. At the age of 15 years the patient again developed symptoms of trachea compression. Radioiodine treatment resulted in a regression of the recurrent goiter and a permanent cure of hyperthyroidism without relapse during the last 3 years of his follow-up. Sequencing of exon 10 of the TSHR gene showed a de novo heterozygous germline I630L mutation, which has been previously described as activating mutation at somatic level in toxic thyroid nodules. The I630L mutation of the TSHR gene occurs not only at somatic level in toxic thyroid nodules, but also its presence in germline is associated with nonautoimmune primary hyperthyroidism. Our case report demonstrates that in this disorder a continuous growth of the thyroid occurs without any evidence of elevated TSH due to antithyroid drug overdosing. This may justify previous recommendations for early treatment of affected

  6. Lateral hypothalamic thyrotropin-releasing hormone neurons: distribution and relationship to histochemically defined cell populations in the rat.

    Science.gov (United States)

    Horjales-Araujo, E; Hellysaz, A; Broberger, C

    2014-09-26

    The lateral hypothalamic area (LHA) constitutes a large component of the hypothalamus, and has been implicated in several aspects of motivated behavior. The LHA is of particular relevance to behavioral state control and the maintenance of arousal. Due to the cellular heterogeneity of this region, however, only some subpopulations of LHA cells have been properly anatomically characterized. Here, we have focused on cells expressing thyrotropin-releasing hormone (TRH), a peptide found in the LHA that has been implicated as a promoter of arousal. Immunofluorescence and in situ hybridization were used to map the LHA TRH population in the rat, and cells were observed to form a large ventral cluster that extended throughout almost the entire rostro-caudal axis of the hypothalamus. Almost no examples of coexistence were seen when sections were double-stained for TRH and markers of other LHA populations, including the peptides hypocretin/orexin, melanin-concentrating hormone and neurotensin. In the juxtaparaventricular area, however, a discrete group of TRH-immunoreactive cells were also stained with antisera against enkephalin and urocortin 3. Innervation from the metabolically sensitive hypothalamic arcuate nucleus was investigated by double-staining for peptide markers of the two centrally projecting groups of arcuate neurons, agouti gene-related peptide and α-melanocyte-stimulating hormone, respectively; both populations of terminals were observed forming close appositions on TRH cells in the LHA. The present study indicates that TRH-expressing cells form a unique population in the LHA that may serve as a link between metabolic signals and the generation of arousal. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Levodopa-induced dyskinesia is associated with increased thyrotropin releasing hormone in the dorsal striatum of hemi-parkinsonian rats.

    Directory of Open Access Journals (Sweden)

    Ippolita Cantuti-Castelvetri

    2010-11-01

    Full Text Available Dyskinesias associated with involuntary movements and painful muscle contractions are a common and severe complication of standard levodopa (L-DOPA, L-3,4-dihydroxyphenylalanine therapy for Parkinson's disease. Pathologic neuroplasticity leading to hyper-responsive dopamine receptor signaling in the sensorimotor striatum is thought to underlie this currently untreatable condition.Quantitative real-time polymerase chain reaction (PCR was employed to evaluate the molecular changes associated with L-DOPA-induced dyskinesias in Parkinson's disease. With this technique, we determined that thyrotropin releasing hormone (TRH was greatly increased in the dopamine-depleted striatum of hemi-parkinsonian rats that developed abnormal movements in response to L-DOPA therapy, relative to the levels measured in the contralateral non-dopamine-depleted striatum, and in the striatum of non-dyskinetic control rats. ProTRH immunostaining suggested that TRH peptide levels were almost absent in the dopamine-depleted striatum of control rats that did not develop dyskinesias, but in the dyskinetic rats, proTRH immunostaining was dramatically up-regulated in the striatum, particularly in the sensorimotor striatum. This up-regulation of TRH peptide affected striatal medium spiny neurons of both the direct and indirect pathways, as well as neurons in striosomes.TRH is not known to be a key striatal neuromodulator, but intrastriatal injection of TRH in experimental animals can induce abnormal movements, apparently through increasing dopamine release. Our finding of a dramatic and selective up-regulation of TRH expression in the sensorimotor striatum of dyskinetic rat models suggests a TRH-mediated regulatory mechanism that may underlie the pathologic neuroplasticity driving dopamine hyper-responsivity in Parkinson's disease.

  8. Hyperthyroidism caused by an ectopic thyrotropin-secreting tumor of the nasopharynx: a case report and review of the literature.

    Science.gov (United States)

    Tong, Anli; Xia, Weibo; Qi, Fang; Jin, Zimeng; Yang, Di; Zhang, Zhuhua; Li, Fang; Xing, Xiaoping; Lian, Xiaolan

    2013-09-01

    Ectopic thyrotropin (TSH)-secreting tumors are extremely rare. To our knowledge, only three cases have previously been reported so far, but the tumors were not studied ultrastructurally and in vitro. We present a case that was extensively examined to gain deeper insights in terms of the histopathological features and hormonal secretion profile of the tumor. A 49-year-old female complained of nasal obstruction for 15 years and thyrotoxicosis for one and a half years. Except for a high basal TSH with concomitantly elevated free tri-iodothyronine (FT3) and free thyroxine (FT4) levels, her pituitary hormone profile yielded normal results. Magnetic resonance imaging revealed a 2 cm × 2 cm mass in the nasopharynx, which showed an increased tracer uptake on octreotide scintigraphy. Preoperative treatment with octreotide effectively reduced serum TSH, FT3, and FT4 to normal levels. The mass was endoscopically removed via an endonasal approach. Immunophenotyping and hormone determination of cultured cells confirmed that the mass was a plurihormonal TSH-/growth hormone (GH)-/prolactin (PRL)-producing adenoma. Co-expression of TSH and GH was found in most cells. Electron microscopy showed that the adenoma was formed by a single cell type, with secretory granules of small size. In vitro studies demonstrated that octreotide reduced both TSH and GH secretion. We report an ectopic TSH-secreting tumor, which had plurihormonal secretion in vitro, including TSH, GH, and PRL. Histologically, it mimicked a TSH-secreting pituitary adenoma. Octreotide was useful in the diagnosis and treatment of this ectopic TSH-secreting tumor. Ectopic TSH-secreting tumors are extremely rare. In terms of hormone secretion profile, histological characteristics, and response to octreotide, they are similar to pituitary TSH-secreting adenomas, suggesting that they are of identical cell origin.

  9. Elucidating the neurotoxic effects of MDMA and its analogs.

    Science.gov (United States)

    Karuppagounder, Senthilkumar S; Bhattacharya, Dwipayan; Ahuja, Manuj; Suppiramaniam, Vishnu; Deruiter, Jack; Clark, Randall; Dhanasekaran, Muralikrishnan

    2014-04-17

    There is a rapid increase in the use of methylenedioxymethamphetamine (MDMA) and its structural congeners/analogs globally. MDMA and MDMA-analogs have been synthesized illegally in furtive dwellings and are abused due to its addictive potential. Furthermore, MDMA and MDMA-analogs have shown to have induced several adverse effects. Hence, understanding the mechanisms mediating this neurotoxic insult of MDMA-analogs is of immense importance for the public health in the world. We synthesized and investigated the neurotoxic effects of MDMA and its analogs [4-methylenedioxyamphetamine (MDA), 2, 6-methylenedioxyamphetamine (MDMA), and N-ethyl-3, 4-methylenedioxyamphetamine (MDEA)]. The stimulatory or the dopaminergic agonist effects of MDMA and MDMA-analogs were elucidated using the established 6-hydroxydopamine lesioned animal model. Additionally, we also investigated the neurotoxic mechanisms of MDMA and MDMA-analogs on mitochondrial complex-I activity and reactive oxygen species generation. MDMA and MDMA-analogs exhibited stimulatory activity as compared to amphetamines and also induced several behavioral changes in the rodents. MDMA and MDMA-analogs enhanced the reactive oxygen generation and inhibited mitochondrial complex-I activity which can lead to neurodegeneration. Hence the mechanism of neurotoxicity, MDMA and MDMA-analogs can enhance the release of monoamines, alter the monoaminergic neurotransmission, and augment oxidative stress and mitochondrial abnormalities leading to neurotoxicity. Thus, our study will help in developing effective pharmacological and therapeutic approaches for the treatment of MDMA and MDMA-analog abuse. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Differences in Brain Glucose Metabolism During Preparation for 131I Ablation in Thyroid Cancer Patients: Thyroid Hormone Withdrawal Versus Recombinant Human Thyrotropin.

    Science.gov (United States)

    Jeong, Hyeonseok S; Choi, Eun Kyoung; Song, In-Uk; Chung, Yong-An; Park, Jong-Sik; Oh, Jin Kyoung

    2017-01-01

    In preparation for 131 I ablation, temporary withdrawal of thyroid hormone is commonly used in patients with thyroid cancer after total thyroidectomy. The current study aimed to investigate brain glucose metabolism and its relationships with mood or cognitive function in these patients using 18 F-fluoro-2-deoxyglucose positron emission tomography ( 18 F-FDG-PET). A total of 40 consecutive adult patients with thyroid carcinoma who had undergone total thyroidectomy were recruited for this cross-sectional study. At the time of assessment, 20 patients were hypothyroid after two weeks of thyroid hormone withdrawal, while 20 received thyroid hormone replacement therapy and were euthyroid. All participants underwent brain 18 F-FDG-PET scans and completed mood questionnaires and cognitive tests. Multivariate spatial covariance analysis and univariate voxel-wise analysis were applied for the image data. The hypothyroid patients were more anxious and depressed than the euthyroid participants. The multivariate covariance analysis showed increases in glucose metabolism primarily in the bilateral insula and surrounding areas and concomitant decreases in the parieto-occipital regions in the hypothyroid group. The level of thyrotropin was positively associated with the individual expression of the covariance pattern. The decreased 18 F-FDG uptake in the right cuneus cluster from the univariate analysis was correlated with the increased thyrotropin level and greater depressive symptoms in the hypothyroid group. These results suggest that temporary hypothyroidism, even for a short period, may induce impairment in glucose metabolism and related affective symptoms.

  11. Synthetic Elucidation of Design Principles for Molecular Qubits

    Science.gov (United States)

    Graham, Michael James

    Quantum information processing (QIP) is an emerging computational paradigm with the potential to enable a vast increase in computational power, fundamentally transforming fields from structural biology to finance. QIP employs qubits, or quantum bits, as its fundamental units of information, which can exist in not just the classical states of 0 or 1, but in a superposition of the two. In order to successfully perform QIP, this superposition state must be sufficiently long-lived. One promising paradigm for the implementation of QIP involves employing unpaired electrons in coordination complexes as qubits. This architecture is highly tunable and scalable, however coordination complexes frequently suffer from short superposition lifetimes, or T2. In order to capitalize on the promise of molecular qubits, it is necessary to develop a set of design principles that allow the rational synthesis of complexes with sufficiently long values of T2. In this dissertation, I report efforts to use the synthesis of series of complexes to elucidate design principles for molecular qubits. Chapter 1 details previous work by our group and others in the field. Chapter 2 details the first efforts of our group to determine the impact of varying spin and spin-orbit coupling on T2. Chapter 3 examines the effect of removing nuclear spins on coherence time, and reports a series of vanadyl bis(dithiolene) complexes which exhibit extremely long coherence lifetimes, in excess of the 100 mus threshold for qubit viability. Chapters 4 and 5 form two complimentary halves of a study to determine the exact relationship between electronic spin-nuclear spin distance and the effect of the nuclear spins on T2. Finally, chapter 6 suggests next directions for the field as a whole, including the potential for work in this field to impact the development of other technologies as diverse as quantum sensors and magnetic resonance imaging contrast agents.

  12. Radioiodine plus recombinant human thyrotropin do not cause acute airway compression and are effective in reducing multinodular goiter

    Energy Technology Data Exchange (ETDEWEB)

    Albino, C.C., E-mail: ccalbino@uol.com.b [Instituto de Diabetes e Endocrinologia de Maringa, PR (Brazil); Graf, H.; Paz-Filho, G. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Hospital das Clinicas. Servico de Endocrinologia e Metabologia; Diehl, L.A. [Universidade Estadual de Londrina (UEL), PR (Brazil); Olandoski, M.; Sabbag, A. [Pontificia Univ. Catolica do Parana (PUCPR), Curitiba, PR (Brazil). Nucleo de Bioestatistica; Buchpiguel, C. [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Radiologia

    2006-03-15

    Recombinant human thyrotropin (rhTSH) reduces the activity of radioiodine required to treat multinodular goiter (MNG), but acute airway compression can be a life-threatening complication. In this prospective, randomized, double-blind, placebo-controlled study, we assessed the efficacy and safety (including airway compression) of different doses of rhTSH associated with a fixed activity of {sup 131}I for treating MNG. Euthyroid patients with MNG (69.3 +- 62.0 mL, 20 females, 2 males, 64 +- 7 years) received 0.1 mg (group I, N = 8) or 0.01 mg (group II, N = 6) rhTSH or placebo (group III, N = 8), 24 h before 1.11 GBq {sup 131}I. Radioactive iodine uptake was determined at baseline and 24 h after rhTSH and thyroid volume (TV, baseline and 6 and 12 months after treatment) and tracheal cross-sectional area (TCA, baseline and 2, 7, 180, and 360 days after rhTSH) were determined by magnetic resonance; antithyroid antibodies and thyroid hormones were determined at frequent intervals. After 6 months, TV decreased significantly in groups I (28.5 +- 17.6%) and II (21.6 +- 17.8%), but not in group III (2.7 +- 15.3%). After 12 months, TV decreased significantly in groups I (36.7 +- 18.1%) and II (37.4 +- 27.1%), but not in group III (19.0 +- 24.3%). No significant changes in TCA were observed. T3 and free T4 increased transiently during the first month. After 12 months, 7 patients were hypothyroid (N 3 in group I and N = 2 in groups II and III). rhTSH plus a 1.11-GBq fixed {sup 131}I activity did not cause acute or chronic changes in TCA. After 6 and 12 months, TV reduction was more pronounced among patients treated with rhTSH plus {sup 131}I (author)

  13. Tumour dosimetry and response in patients with metastatic differentiated thyroid cancer using recombinant human thyrotropin before radioiodine therapy

    Energy Technology Data Exchange (ETDEWEB)

    Keizer, Bart de; Hoekstra, Anne; Rijk, Peter P. van; Klerk, John M.H. de [Department of Nuclear Medicine, Room E02.222, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht (Netherlands); Brans, Boudewijn; Dierckx, Rudi A. [Department of Nuclear Medicine, Ghent University Hospital, Ghent (Belgium); Zelissen, Pierre M.J.; Koppeschaar, Hans P.F.; Lips, Cees J.M. [Department of Endocrinology, University Medical Center Utrecht (Netherlands)

    2003-03-01

    The development of recombinant human thyrotropin (rhTSH) has given clinicians new options for diagnostic follow-up and treatment of patients with differentiated thyroid cancer (DTC). This paper evaluates the tumour dosimetry and response following -iodine-131 treatment of metastatic thyroid cancer patients after rhTSH stimulation instead of classical hormone withdrawal-induced hypothyroidism. Nineteen consecutive {sup 131}I treatments in 16 patients were performed after rhTSH stimulation. All patients had undergone a near-total thyroidectomy followed by an ablative dosage of {sup 131}I. They all suffered from metastatic or recurrent disease showing tumoral {sup 131}I uptake on previous post-treatment scintigraphy. Dosimetric calculations were performed using {sup 131}I tumour uptake measurements from post-treatment {sup 131}I scintigrams and tumour volume estimations from radiological images. Response was assessed by comparing pre-treatment serum thyroglobulin (Tg) level with the Tg level 3 months post treatment. In 18 out of 19 treatments, uptake of {sup 131}I in metastatic or recurrent lesions was seen. The median tumour radiation dose was 26.3 Gy (range 1.3-368 Gy), and the median effective half-life was 2.7 days (range 0.5-6.5 days). Eleven of 19 treatments (10/16 patients) were evaluable for response after 3 months. {sup 131}I therapy with rhTSH resulted in a biochemical partial response in 3/11 or 27% of treatments (two patients), biochemical stable disease in 2/11 or 18% of treatments and biochemical progressive disease in 6/11 or 55% of treatments. Our study showed that although tumour doses in DTC patients treated with {sup 131}I after rhTSH were highly variable, 45% of treatments led to disease stabilisation or partial remission when using rhTSH in conjunction with {sup 131}I therapy, without serious side-effects and with minimal impact on quality of life. RhTSH is therefore adequately satisfactory as an adjuvant tool in therapeutic settings and is

  14. Intracellular postsynaptic cannabinoid receptors link thyrotropin-releasing hormone receptors to TRPC-like channels in thalamic paraventricular nucleus neurons.

    Science.gov (United States)

    Zhang, L; Kolaj, M; Renaud, L P

    2015-12-17

    In rat thalamic paraventricular nucleus of thalamus (PVT) neurons, activation of thyrotropin-releasing hormone (TRH) receptors enhances excitability via concurrent decrease in G protein-coupled inwardly-rectifying potassium (GIRK)-like and activation of transient receptor potential cation (TRPC)4/5-like cationic conductances. An exploration of intracellular signaling pathways revealed the TRH-induced current to be insensitive to phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitors, but reduced by D609, an inhibitor of phosphatidylcholine-specific PLC (PC-PLC). A corresponding change in the I-V relationship implied suppression of the cationic component of the TRH-induced current. Diacylglycerol (DAG) is a product of the hydrolysis of PC. Studies focused on the isolated cationic component of the TRH-induced response revealed a reduction by RHC80267, an inhibitor of DAG lipase, the enzyme involved in the hydrolysis of DAG to the endocannabinoid 2-arachidonoylglycerol (2-AG). Further investigation revealed enhancement of the cationic component in the presence of either JZL184 or WWL70, inhibitors of enzymes involved in the hydrolysis of 2-AG. A decrease in the TRH-induced response was noted in the presence of rimonabant or SR144528, membrane permeable CB1 and CB2 receptor antagonists, respectively. A decrease in the TRH-induced current by intracellular, but not by bath application of the membrane impermeable peptide hemopressin, selective for CB1 receptors, suggests a postsynaptic intracellular localization of these receptors. The TRH-induced current was increased in the presence of arachidonyl-2'-chloroethylamide (ACEA) or JWH133, CB1 and CB2 receptor agonists, respectively. The PI3-kinase inhibitor LY294002, known to inhibit TRPC translocation, decreased the response to TRH. In addition, a TRH-induced enhancement of the low-threshold spike was prevented by both rimonabant, and SR144528. TRH had no influence on excitatory or inhibitory miniature

  15. Radioiodine plus recombinant human thyrotropin do not cause acute airway compression and are effective in reducing multinodular goiter

    International Nuclear Information System (INIS)

    Albino, C.C.; Graf, H.; Paz-Filho, G.; Olandoski, M.; Sabbag, A.; Buchpiguel, C.

    2006-01-01

    Recombinant human thyrotropin (rhTSH) reduces the activity of radioiodine required to treat multinodular goiter (MNG), but acute airway compression can be a life-threatening complication. In this prospective, randomized, double-blind, placebo-controlled study, we assessed the efficacy and safety (including airway compression) of different doses of rhTSH associated with a fixed activity of 131 I for treating MNG. Euthyroid patients with MNG (69.3 ± 62.0 mL, 20 females, 2 males, 64 ± 7 years) received 0.1 mg (group I, N = 8) or 0.01 mg (group II, N = 6) rhTSH or placebo (group III, N = 8), 24 h before 1.11 GBq 131 I. Radioactive iodine uptake was determined at baseline and 24 h after rhTSH and thyroid volume (TV, baseline and 6 and 12 months after treatment) and tracheal cross-sectional area (TCA, baseline and 2, 7, 180, and 360 days after rhTSH) were determined by magnetic resonance; antithyroid antibodies and thyroid hormones were determined at frequent intervals. After 6 months, TV decreased significantly in groups I (28.5 ± 17.6%) and II (21.6 ± 17.8%), but not in group III (2.7 ± 15.3%). After 12 months, TV decreased significantly in groups I (36.7 ± 18.1%) and II (37.4 ± 27.1%), but not in group III (19.0 ± 24.3%). No significant changes in TCA were observed. T3 and free T4 increased transiently during the first month. After 12 months, 7 patients were hypothyroid (N 3 in group I and N = 2 in groups II and III). rhTSH plus a 1.11-GBq fixed 131 I activity did not cause acute or chronic changes in TCA. After 6 and 12 months, TV reduction was more pronounced among patients treated with rhTSH plus 131 I (author)

  16. Advances in applied homeostatic modelling of the relationship between thyrotropin and free thyroxine.

    Directory of Open Access Journals (Sweden)

    Rudolf Hoermann

    Full Text Available The relationship between pituitary TSH and thyroid hormones is central to our understanding of thyroid physiology and thyroid function testing. Here, we generated distribution patterns by using validated tools of thyroid modelling.We simulated patterns of individual set points under various conditions, based on a homeostatic model of thyroid feedback control. These were compared with observed data points derived from clinical trials.A random mix of individual set points was reconstructed by simulative modelling with defined structural parameters. The pattern displayed by the cluster of hypothetical points resembled that observed in a natural control group. Moderate variation of the TSH-FT4 gradient over the functional range introduced further flexibility, implementing a scenario of adaptive set points. Such a scenario may be a realistic possibility for instance in treatment where relationships and equilibria between thyroid parameters are altered by various influences such as LT4 dose and conversion efficiency.We validated a physiologically based homeostatic model that permits simulative reconstruction of individual set points. This produced a pattern resembling the observed data under various conditions. Applied modelling, although still experimental at this stage, shows a potential to aid our physiological understanding of the interplay between TSH and thyroid hormones. It should eventually benefit personalised clinical decision making.

  17. Differential regulation of thyrotropin subunit apoprotein and carbohydrate biosynthesis by thyroid hormone

    International Nuclear Information System (INIS)

    Taylor, T.; Weintraub, B.D.

    1985-01-01

    The regulation of TSH apoprotein and carbohydrate biosynthesis by thyroid hormone was studied by incubating pituitaries from normal and hypothyroid (3 weeks post-thyroidectomy) rats in medium containing [ 14 C]alanine and [ 3 H] glucosamine. After 6 h, samples were sequentially treated with anti-TSH beta to precipitate TSH and free TSH beta, anti-LH beta to clear the sample of LH and free LH beta, then anti-LH alpha to precipitate free alpha-subunit. Total proteins were acid precipitated. All precipitates were subjected to electrophoresis on sodium dodecyl sulfate-polyacrylamide gels, which were then sliced and assayed by scintillation spectrometry. In hypothyroid pituitaries plus medium, [ 14 C]alanine incorporation in combined and free beta-subunits was 26 times normal and considerably greater than the 3.4-fold increase seen in total protein; combined and free alpha-subunits showed no specific increase in apoprotein synthesis. [ 3 H]Glucosamine incorporation in combined alpha- and beta-subunits in hypothyroid samples was 13 and 21 times normal, respectively, and was greater than the 1.9-fold increase in total protein; free alpha-subunit showed no specific increase in carbohydrate synthesis. The glucosamine to alanine ratio, reflecting relative glycosylation of newly synthesized molecules, was increased in hypothyroidism for combined alpha-subunits, but not for combined beta-subunits, free alpha-subunits, or total proteins. In summary, short term hypothyroidism selectively stimulated TSH beta apoprotein synthesis and carbohydrate synthesis of combined alpha- and beta-subunits. Hypothyroidism also increased the relative glycosylation of combined alpha-subunit. Thus, thyroid hormone deficiency appears to alter the rate-limiting step in TSH assembly (i.e. beta-subunit synthesis) as well as the carbohydrate structure of TSH, which may play important roles in its biological function

  18. Elucidation and in planta reconstitution of the parthenolide biosynthetic pathway

    DEFF Research Database (Denmark)

    Liu, Qing; Manzano, David; Tanić, Nikola

    2014-01-01

    Parthenolide, the main bioactive compound of the medicinal plant feverfew (Tanacetum parthenium), is a promising anti-cancer drug. However, the biosynthetic pathway of parthenolide has not been elucidated yet. Here we report on the isolation and characterization of all the genes from feverfew tha...

  19. 64 kDa protein is a candidate for a thyrotropin-releasing hormone receptor in prolactin-producing rat pituitary tumor cells (GH4C1 cells)

    International Nuclear Information System (INIS)

    Wright, M.; Hogset, A.; Alestrom, P.; Gautvik, K.M.

    1988-01-01

    A thyrotropin-releasing hormone (TRH) binding protein of 64 kDa has been identified by covalently crosslinking [ 3 H]TRH to GH4C1 cells by ultraviolet illumination. The crosslinkage of [ 3 H]TRH is UV-dose dependent and is inhibited by an excess of unlabeled TRH. A 64 kDa protein is also detected on immunoblots using an antiserum raised against GH4C1 cell surface epitopes. In a closely related cell line (GH12C1) which does not bind [ 3 H]TRH, the 64 kDa protein cannot be demonstrated by [ 3 H]TRH crosslinking nor by immunoblotting. These findings indicate that the 64 kDa protein is a candidate for a TRH-receptor protein in GH4C1 cells

  20. Effects of long-term intraperitoneal injection of thyrotropin-releasing hormone (TRH) on aging- and obesity-related changes in body weight, lipid metabolism, and thyroid functions.

    Science.gov (United States)

    Pierpaoli, Walter; Lesnikov, Vladimir A

    2011-02-01

    Adult adipose mice, high fat diet-fed (HFD) mice, anterior hypothalamus-lesioned obese mice and genetically obese mice, were injected daily with thyrotropin releasing hormone (TRH). The treatment provoked a mobilization of triglycerides in the peripheral blood, a decrease of leptin and a loss of body weight. The weight loss did not depend on TSH-mediated stimulation of thyroid hormone secretion with consequent metabolic hyperthyroidism. The levels of blood cholesterol were not affected or even suppressed. Even at a very high dosage TRH did not affect the obesity of genetically obese mice. The ubiquitous tripeptide TRH may thus constitute a key element in the hormone-controlled regulation of body weight and fat stores in the adult and aging body.

  1. Thyrotropin receptor antibody activities significantly correlate with the outcome of radioiodine ( sup 131 I) therapy for hyperthyroid Graves' disease

    Energy Technology Data Exchange (ETDEWEB)

    Kaise, Kazuro; Kaise, Nobuko; Yoshida, Katsumi; Fukazawa, Hiroshi; Mori, Koki; Yamamoto, Makiko; Sakurada, Toshiro; Saito, Shintaro; Yoshinaga, Kaoru (Tohoku Univ., Sendai (Japan). School of Medicine)

    1991-08-01

    The outcome of {sup 131}I therapy for 109 patients with Graves' disease was analysed according to pretreatment laboratory data including thyrotropin receptor antibody (TRAb) activities. Forty-five percent of patients became euthyroid, and 13% of patients became hypothyroid within one year after {sup 131}I therapy. Forty-two percent of patients remained hyperthyroid one year after {sup 131}I therapy. Pretreatment values for serum T{sub 4}, T{sub 3}, and the estimated weight of the thyroid were significantly higher in the hyperthyroid group. The mean for the TRAb index of the hyperthyroid group was significantly higher than that of the euthyroid group. Life table analysis revealed a significant effect of the TRAb index on the rate of hyperthyroidism after 3 months or later. These results appear to suggest that the TRAb index is one of the factors which influence the outcome of {sup 131}I therapy for Graves' disease. (author).

  2. Quality characteristics of chemicals for the radioimmunoassay of thyroxine and thyrotropin.; Caracteristicas de calidad de reactivos para el radioinmunoanalisis de tiroxina y tirotropina.

    Energy Technology Data Exchange (ETDEWEB)

    Verdeja I, C E

    1994-12-31

    Radioimmunoassay is a form of saturation analysis in which the test material competes with labelled antigen for a limited amount of antibody, the amount of label displaced being a measure of the antigen in the test sample. In this country, the kits for Radioimmunoassay (RIA) are imported, and this increase the cost of it. Because this lack of production, the National Institute of Nuclear Research (ININ) has developed RIA`s kits for the thyroxine (T{sub 4}), Thyrotropin (TSH) and Triyodotironine (T{sub 3}) hormones. This work presents the conclusions of the test recommended by the WHO. The quality test were: recuperation, cross reactions, basic parameters, intra and inter assay variations, sensibility and others. The results show that the RIA`s kits of the ININ have a good behavior and can be use in the clinical laboratory. (Author).

  3. Clinicopathological characteristics and therapeutic outcomes in thyrotropin-secreting pituitary adenomas: a single-center study of 90 cases.

    Science.gov (United States)

    Yamada, Shozo; Fukuhara, Noriaki; Horiguchi, Kentaro; Yamaguchi-Okada, Mitsuo; Nishioka, Hiroshi; Takeshita, Akira; Takeuchi, Yasuhiro; Ito, Junko; Inoshita, Naoko

    2014-12-01

    The aim of this study was to analyze clinicopathological characteristics and treatment outcomes in a large single-center clinical series of cases of thyrotropin (TSH)-secreting pituitary adenomas. The authors retrospectively reviewed clinical, pathological, and treatment characteristics of 90 consecutive cases of TSH-secreting pituitary adenomas treated with transsphenoidal surgery between December 1991 and May 2013. The patient group included 47 females and 43 males (median age 42 years, range 11-74 years). Sixteen tumors (18%) were microadenomas and 74 (82%) were macroadenomas. Microadenomas were significantly more frequent in the more recent half of our case series (12 of 45 cases) (p = 0.0274). Cavernous sinus invasion was confirmed in 21 patients (23%). In 67 cases (74%), the tumors were firm elastic or hard in consistency. Acromegaly and hyperprolactinemia were observed, respectively, in 14 (16%) and 11 (12%) of the 90 cases. Euthyroidism was achieved in 40 (83%) of 48 patients and tumor shrinkage was found in 24 (55%) of 44 patients following preoperative somatostatin analog treatment. Conventional transsphenoidal surgery, extended transsphenoidal surgery, and a simultaneous combined supra- and infrasellar approach were performed in 85, 2, and 3 patients, respectively. Total removal with endocrinological remission was achieved in 76 (84%) of 90 patients, including all 16 (100%) patients with microadenomas, 60 (81%) of the 74 with macroadenomas, and 8 (38%) of the 21 with cavernous sinus invasion. None of these 76 patients experienced tumor recurrence during a median follow-up period of 2.8 years. Stratifying by Knosp grade, total removal with endocrinological remission was achieved in 34 of 36 patients with Knosp Grade 0 tumors, all 24 of those with Grade 1 tumors, 12 of the 14 with Grade 2 tumors, 6 of the 8 with Grade 3 tumors, and none of the 8 with Grade 4 tumors. Cavernous sinus invasion and tumor size were significant independent predictors of surgical

  4. Elucidation of Molecular Pathogenic Mechanisms of Norrie Disease

    OpenAIRE

    Luhmann, Ulrich F.O.

    2010-01-01

    Summary Norrie disease (ND) is a rare X-linked recessive congenital blindness, sometimes associated with deafness and mental retardation. In this thesis the molecular pathogenic mechanisms of this syndrome should be elucidated using the Ndph knockout mouse model. Gene expression studies but also histology and protein biochemistry were used to characterize the affected organs, eye and brain. Gene expression analyses of eyes at p21 using cDNA subtrac...

  5. Elucidate Innovation Performance of Technology-driven Mergers and Acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L.; Wang, K.; Yu, H.; Shang, L.; Mitkova, L.

    2016-07-01

    The importance and value of Mergers and Acquisitions (M&As) have increased with the expectancy to obtain key technology capabilities and rapid impact on innovation. This article develops an original analytical framework to elucidate the impact of the technology and product relatedness (similarity/complementarity) of the Technology-driven M&A’ partners on post-innovation performance. We present results drawing on a multiple case studies of Chinese High-Tech firms from three industries. (Author)

  6. Elucidation of the biosynthesis of meroterpenoid yanuthone D in Aspergillus Niger

    DEFF Research Database (Denmark)

    Holm, Dorte Koefoed; Petersen, Lene Maj; Klitgaard, Andreas

    2012-01-01

    We have elucidated the mode of biosynthesis of the meroterpenoid compound Yanuthone D in Aspergillus niger. We have successfully deleted all cluster genes, and identified a number of intermediates. Structures of the intermediates were solved using a combined approach comprising classical 1D- and 2D......-NMR and tandem mass spectrometry (MS/MS). In this study we have confirmed that Yanuthone D is of meroterpenoid origin, and we have identified an unexpected precursor, which has not before been reported for Aspergillus niger....

  7. Ravynic acid, an antibiotic polyeneyne tetramic acid from Penicillium sp. elucidated through synthesis.

    Science.gov (United States)

    Myrtle, J D; Beekman, A M; Barrow, R A

    2016-09-21

    A new antibiotic natural product, ravynic acid, has been isolated from a Penicillium sp. of fungus, collected from Ravensbourne National Park. The 3-acylpolyenyne tetramic acid structure was definitively elucidated via synthesis. Highlights of the synthetic method include the heat induced formation of the 3-acylphosphorane tetramic acid and a selective Wittig cross-coupling to efficiently prepare the natural compounds carbon skeleton. The natural compound was shown to inhibit the growth of Staphylococcus aureus down to concentrations of 2.5 µg mL(-1).

  8. Established Stem Cell Model of Spinal Muscular Atrophy Is Applicable in the Evaluation of the Efficacy of Thyrotropin-Releasing Hormone Analog.

    Science.gov (United States)

    Ohuchi, Kazuki; Funato, Michinori; Kato, Zenichiro; Seki, Junko; Kawase, Chizuru; Tamai, Yuya; Ono, Yoko; Nagahara, Yuki; Noda, Yasuhiro; Kameyama, Tsubasa; Ando, Shiori; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki; Kaneko, Hideo

    2016-02-01

    Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by the degeneration of spinal motor neurons. This disease is mainly caused by mutation or deletion of the survival motor neuron 1 (SMN1) gene. Currently, no effective treatment is available, and only symptomatic treatment can be provided. Our purpose in the present study was to establish a human SMA-derived induced pluripotent stem cell (SMA-iPSC) disease model and assay a therapeutic drug in preparation for the development of a novel treatment of SMA. We generated iPSCs from the skin fibroblasts of a patient with SMA and confirmed that they were pluripotent and undifferentiated. The neural differentiation of SMA-iPSCs shortened the dendrite and axon length and increased the apoptosis of the spinal motor neurons. In addition, we found activated astrocytes in differentiated SMA-iPSCs. Using this model, we confirmed that treatment with the thyrotropin-releasing hormone (TRH) analog, 5-oxo-l-prolyl-l-histidyl-l-prolinamide, which had marginal effects in clinical trials, increases the SMN protein level. This increase was mediated through the transcriptional activation of the SMN2 gene and inhibition of glycogen synthase kinase-3β activity. Finally, the TRH analog treatment resulted in dendrite and axon development of spinal motor neurons in differentiated SMA-iPSCs. These results suggest that this human in vitro disease model stimulates SMA pathology and reveal the potential efficacy of TRH analog treatment for SMA. Therefore, we can screen novel therapeutic drugs such as TRH for SMA easily and effectively using the human SMA-iPSC model. Significance: Platelet-derived growth factor (PDGF) has recently been reported to produce the greatest increase in survival motor neuron protein levels by inhibiting glycogen synthase kinase (GSK)-3β; however, motor neurons lack PDGF receptors. A human in vitro spinal muscular atrophy-derived induced pluripotent stem cell model was

  9. Thyrotropin-Blocking Autoantibodies and Thyroid-Stimulating Autoantibodies: Potential Mechanisms Involved in the Pendulum Swinging from Hypothyroidism to Hyperthyroidism or Vice Versa

    Science.gov (United States)

    Rapoport, Basil

    2013-01-01

    Background Thyrotropin receptor (TSHR) antibodies that stimulate the thyroid (TSAb) cause Graves' hyperthyroidism and TSHR antibodies which block thyrotropin action (TBAb) are occasionally responsible for hypothyroidism. Unusual patients switch from TSAb to TBAb (or vice versa) with concomitant thyroid function changes. We have examined case reports to obtain insight into the basis for “switching.” Summary TBAb to TSAb switching occurs in patients treated with levothyroxine (LT4); the reverse switch (TBAb to TSAb) occurs after anti-thyroid drug therapy; TSAb/TBAb alterations may occur during pregnancy and are well recognized in transient neonatal thyroid dysfunction. Factors that may impact the shift include: (i) LT4 treatment, usually associated with decreased thyroid autoantibodies, in unusual patients induces or enhances thyroid autoantibody levels; (ii) antithyroid drug treatment decreases thyroid autoantibody levels; (iii) hyperthyroidism can polarize antigen-presenting cells, leading to impaired development of regulatory T cells, thereby compromising control of autoimmunity; (iv) immune-suppression/hemodilution reduces thyroid autoantibodies during pregnancy and rebounds postpartum; (v) maternally transferred IgG transiently impacts thyroid function in neonates until metabolized; (vi) a Graves' disease model involving immunizing TSHR-knockout mice with mouse TSHR-adenovirus and transfer of TSHR antibody-secreting splenocytes to athymic mice demonstrates the TSAb to TBAb shift, paralleling the outcome of maternally transferred “term limited” TSHR antibodies in neonates. Finally, perhaps most important, as illustrated by dilution analyses of patients' sera in vitro, TSHR antibody concentrations and affinities play a critical role in switching TSAb and TBAb functional activities in vivo. Conclusions Switching between TBAb and TSAb (or vice versa) occurs in unusual patients after LT4 therapy for hypothyroidism or anti-thyroid drug treatment for Graves

  10. The assay of thyrotropin receptor antibodies with human TSH/LH-CG chimeric receptor expressed on chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Yi, Ka Hee; Kim, Chang Min

    1996-12-01

    TSH/LH-CG chimera cDNA is transfected to CHO-K1 cell to obtain the chimeric receptor expressed on the cell surface. The optimal conditions for TSAb and TSBAb measurements are determined using chimeric receptors and under these conditions activity of TSAb and TSBAb in the sera of the Graves' patients. The results obtained are compared to those of TSAb assays using FRTL5 cells CHO-TSHR cells which have wild type human TSH receptor. The transfection procedure of chimeric receptor gene to CHO-K1 cells are on going. The optimal conditions for TSAb and TSBAb measurement using chimeric receptor will be determined after success of transfection procedure. If this study is successfully completed, not only the heterogeneity of Graves. IgG but also pathogenesis of Graves' disease will be elucidated. (author). 25 refs

  11. The assay of thyrotropin receptor antibodies with human TSH/LH-CG chimeric receptor expressed on chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ka Hee; Kim, Chang Min [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1996-12-01

    TSH/LH-CG chimera cDNA is transfected to CHO-K1 cell to obtain the chimeric receptor expressed on the cell surface. The optimal conditions for TSAb and TSBAb measurements are determined using chimeric receptors and under these conditions activity of TSAb and TSBAb in the sera of the Graves` patients. The results obtained are compared to those of TSAb assays using FRTL5 cells CHO-TSHR cells which have wild type human TSH receptor. The transfection procedure of chimeric receptor gene to CHO-K1 cells are on going. The optimal conditions for TSAb and TSBAb measurement using chimeric receptor will be determined after success of transfection procedure. If this study is successfully completed, not only the heterogeneity of Graves. IgG but also pathogenesis of Graves` disease will be elucidated. (author). 25 refs.

  12. STATUS SOSIAL-EKONOMI DAN KADAR HORMON TIROTROPIN RUMAH-TANGGA PENGGUNA GARAM BERIDOIUM DI PERKOTAAN INDONESIA : ANALISIS DATA RISKESDAS 2007 (SOCIO-ECONOMIC STATUS AND THYROTROPIN HORMONE LEVEL OF HOUSEHOLDS USING IODIZED SALT IN INDONESIAN URBAN : ANA

    Directory of Open Access Journals (Sweden)

    Djoko Kartono

    2012-12-01

    Full Text Available ABSTRACT Iodized salt is the long term and sustainable strategy to improve iodine intakeof the community.Level of thyroid stimulating hormone (thyrotropin hormone can be used as indicator of iodine intake adequacy. To study the socio-economic status of households using iodized salt and thyrotropin hormone level in urban areas. Riskesdas data 2007 that include 280.000 households was used.Thyrotropin hormone data include 9.457 people aged above 1 years. Variables included classification of village, rapid test on salt, education and occupation of households’ head, household expenditure and level of thyrotropin hormone. Around 80 percentof households where households’ head graduated from college/university used salt containing sufficient iodine. Only 18 percent households with households’ headworks as government workers used salt containing sufficient iodine. Around 70 percent households in 5th quintile of household’s expenditure were using salt with sufficient iodine content. Around 70 percent households in urban areas were using salt withsufficient iodine content.Among children 1-4 years, percentage of low category of thyrotropin hormon level was 3.3 percentand among 60 years of age and above was 15.8 percent. The higher the educational levelthe higher the percentage of households used salt with sufficient iodine. Percentage of households using salt with sufficient iodine was higher in urban than in rural areas. The higher the quintiles of household expenditures the higher the percentage of households using salt with sufficient iodine. There was a trend that the higher the age the higher the percentage of low category of thyrotropin hormone level. Keywords: householdsalt, education, occupation, urban, rural, expenditure, thyrotropin hormone   ABSTRAK Garam beriodium merupakan strategi jangka panjang dan berkesinambungan untuk memperbaiki asupan iodium masyarakat. Sementara itu, kadar thyroid stimulating hormone (hormon tirotropin dapat

  13. Seasonal Changes in Serum Thyrotropin Concentrations Observed from Big Data Obtained During Six Consecutive Years from 2010 to 2015 at a Single Hospital in Japan.

    Science.gov (United States)

    Yoshihara, Ai; Noh, Jaeduk Yoshimura; Watanabe, Natsuko; Iwaku, Kenji; Kunii, Yo; Ohye, Hidemi; Suzuki, Miho; Matsumoto, Masako; Suzuki, Nami; Sugino, Kiminori; Thienpont, Linda M; Hishinuma, Akira; Ito, Koichi

    2018-04-01

    This study analyzed big data for serum thyrotropin (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) concentrations in patients who had attended the outpatient clinic of Ito Hospital (Tokyo, Japan) during a recent six-year period (between January 1, 2010, and December 31, 2015) in order to investigate for seasonal changes. The serum TSH concentrations were reviewed for all 135,417 patients aged >20 years. Patients with any thyroid diseases were included, irrespective of whether they were receiving drug therapy. In total 1,637,721 serum samples were analyzed for TSH, 1,626,269 for fT3, and 1,669,381 for fT4. It was observed that the TSH concentrations showed annual changes during the six-year period. They decreased during the summer, while they increased during the winter. The TSH concentrations were negatively correlated with the daily temperatures (Spearman rank correlation coefficient -0.4486; p < 0.0001). The same applied for the correlation between fT3 concentrations and daily temperatures. The fact that the TSH concentrations show annual changes in areas where the temperature ranges during the year are rather wide should be borne in mind for interpretation of results.

  14. Effects of metamorphosis and captivity on the in vitro sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin

    International Nuclear Information System (INIS)

    Norman, M.F.; Norris, D.O.

    1987-01-01

    The sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin (bTSH) was tested in vitro. Thyroids were taken from subjects representing metamorphic stages I (premetamorphic larvae), II (onset of climax), and VII (completion of gill resorption), as well as from captivity control larvae. Exogenous TSH reduced the cumulative uptake of 125 I in vitro by thyroids from stage I larvae after 24 and 48 hr. The capacity of thyroids to release thyroxine (T4) in vitro was used subsequently as a measure of their responsiveness to TSH. Baseline levels of T4 release in vitro were variable but did not differ significantly among developmental stages. A low dose of bTSH (5 X 10(-6) IU/ml) did not increase in vitro T4 release compared with that of controls. A larger dose (5 X 10(-4) IU/ml) caused greater increases in T4 release from thyroids of stage II and VII subjects than from those of controls. This dose produced only a small response by thyroids from captivity-control subjects. The results suggest that the thyroids of Ambystoma increase in their capacity to respond to TSH during the process of metamorphosis

  15. A novel deletion in the thyrotropin Beta-subunit gene identified by array comparative genomic hybridization analysis causes central congenital hypothyroidism in a boy originating from Turkey.

    Science.gov (United States)

    Hermanns, Pia; Couch, Robert; Leonard, Norma; Klotz, Cherise; Pohlenz, Joachim

    2014-01-01

    Isolated central congenital hypothyroidism (ICCH) is rare but important. Most ICCH patients are diagnosed later, which results in severe growth failure and intellectual disability. We describe a boy with ICCH due to a large homozygous TSHβ gene deletion. A 51-day-old male Turkish infant, whose parents were first cousins, was admitted for evaluation of prolonged jaundice. His clinical appearance was compatible with hypothyroidism. Venous thyrotropin (TSH) was undetectably low, with a subsequent low free T4 and a low free T3, suggestive of central hypothyroidism. Using different PCR protocols, we could not amplify both coding exons of the boy's TSHβ gene, which suggested a deletion. An array comparative genomic hybridization (aCGH) using specific probes around the TSHβ gene locus showed him to be homozygous for a 6-kb deletion spanning all exons and parts of the 5' untranslated region of the gene. Infants who are clinically suspected of having hypothyroidism should be evaluated thoroughly, even if their TSH-based screening result is normal. In cases with ICCH and undetectably low TSH serum concentrations, a TSHβ gene deletion should be considered; aCGH should be performed when gene deletions are suspected. In such cases, PCR-based sequencing techniques give negative results.

  16. Diagnostic accuracy of circulating thyrotropin receptor messenger RNA combined with neck ultrasonography in patients with Bethesda III-V thyroid cytology.

    Science.gov (United States)

    Aliyev, Altay; Patel, Jinesh; Brainard, Jennifer; Gupta, Manjula; Nasr, Christian; Hatipoglu, Betul; Siperstein, Allan; Berber, Eren

    2016-01-01

    The aim of this study was to analyze the usefulness of thyrotropin receptor messenger RNA (TSHR-mRNA) combined with neck ultrasonography (US) in the management of thyroid nodules with Bethesda III-V cytology. Cytology slides of patients with a preoperative fine needle aspiration (FNA) and TSHR-mRNA who underwent thyroidectomy between 2002 and 2011 were recategorized based on the Bethesda classification. Results of thyroid FNA, TSHR-mRNA, and US were compared with the final pathology. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. There were 12 patients with Bethesda III, 112 with Bethesda IV, and 58 with Bethesda V cytology. The sensitivity of TSHR-mRNA in predicting cancer was 33%, 65%, and 79 %, and specificity was 67%, 66%, and 71%, for Bethesda III, IV, and V categories, respectively. For the same categories, the PPV of TSHR-mRNA was 25%, 33%, and 79%, respectively; whereas the NPV was 75%, 88%, and 71%, respectively. The addition of neck US to TSHR-mRNA increased the NPV to 100% for Bethesda III, and 86%, for Bethesda IV, and 82% for Bethesda V disease. This study documents the potential usefulness of TSHR-mRNA for thyroid nodules with Bethesda III-V FNA categories. TSHR-mRNA may be used to exclude Bethesda IV disease. A large sample analysis is needed to determine its accuracy for Bethesda category III nodules. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Mutations in the thyrotropin receptor signal transduction pathway in the hyperfunctioning thyroid nodules from multinodular goiters: a study in the Turkish population.

    Science.gov (United States)

    Gozu, Hulya; Avsar, Melike; Bircan, Rifat; Sahin, Serap; Deyneli, Oguzhan; Cirakoglu, Beyazit; Akalin, Sema

    2005-10-01

    Many studies have been carried out to determine G(s) alpha and TSHR mutations in autonomously functioning thyroid nodules. Variable prevalences for somatic constitutively activating TSHR mutations in hot nodules have been reported. Moreover, the increased prevalence of toxic multinodular goiters in iodine-deficient regions is well known. In Turkey, a country with high incidence rates of goiter due to iodine deficiency, the frequency of mutations in the thyrotropin receptor signal transduction pathway has not been evaluated up to now. In the present study, a part of the genes of the TSHR, G(s)alpha and the catalytic subunit of the PKA were checked for activating mutations. Thirty-five patients who underwent thyroidectomy for multinodular goiters were examined. Genomic DNAs were extracted from 58 hyperactive nodular specimens and surrounding normal thyroid tissues. Mutation screening was done by single-strand conformational polymorphism (SSCP) analysis. In those cases where a mutation was detected, the localization of the mutation was determined by automatic DNA sequencing. No G(s)alpha or PKA mutations were detected, whereas ten mutations (17%) were identified in the TSHR gene. All mutations were somatic and heterozygotic. In conclusion, the frequency of mutations in the cAMP signal transduction pathway was found to be lower than expected in the Turkish population most likely because of the use of SSCP as a screening method and sequencing only a part of TSHR exon 10.

  18. Frequency and Clinical Implication of the R450H Mutation in the Thyrotropin Receptor Gene in the Japanese Population Detected by Smart Amplification Process 2

    Science.gov (United States)

    Yanagawa, Yoshimaro; Aoki, Tomoyuki; Morimura, Tadashi; Araki, Osamu; Kimura, Takao; Ogiwara, Takayuki; Kotajima, Nobuo; Yanagawa, Masumi; Murakami, Masami

    2014-01-01

    In Japanese pediatric patients with thyrotropin (TSH) resistance, the R450H mutation in TSH receptor gene (TSHR) is occasionally observed. We studied the frequency and clinical implication of the R450H mutation in TSHR in the general population of Japanese adults using smart amplification process 2 (SmartAmp2). We designed SmartAmp2 primer sets to detect this mutation using a drop of whole blood. We analyzed thyroid function, antithyroid antibodies, and this mutation in 429 Japanese participants who had not been found to have thyroid disease. Two cases without antithyroid antibodies were heterozygous for the R450H mutation in TSHR. Thus, the prevalence of this mutation was 0.47% in the general population and 0.63% among those without antithyroid antibodies. Their serum TSH concentrations were higher than the average TSH concentration not only in subjects without antithyroid antibodies but also in those with antithyroid antibodies. The R450H mutation in TSHR is relatively common in the Japanese population and potentially affects thyroid function. The present study demonstrates that the SmartAmp2 method is useful to detect the R450H mutation in TSHR, which is one of the common causes of TSH resistance in the Japanese population. PMID:24895636

  19. Elucidation and control of electronic properties related to organic semiconductors

    International Nuclear Information System (INIS)

    Yamane, Hiroyuki; Ueno, Nobuo; Seki, Kazuhiko

    2009-01-01

    The electronic structure of organic solids and interfaces plays a crucial role in the performance of optoelectronic devices using organic semiconductors such as light-emitting diodes, field-effect transistors, and photovoltaic cells. The functionality of these organic devices is seriously dominated by the geometric structure, which varies depending on the molecular structure and the sample preparation condition. Due to the rapid progress in sample preparation methods and surface science techniques, we can now discuss in detail the correlation of the electronic structure with the geometric structure of organic solids, films, and interfaces. This paper reviews the recent progress of studies in the geometric and electronic structures related to organic semiconductors. (author)

  20. In silico functional elucidation of uncharacterized proteins of Chlamydia abortus strain LLG.

    Science.gov (United States)

    Singh, Gagandeep; Sharma, Dixit; Singh, Vikram; Rani, Jyoti; Marotta, Francessco; Kumar, Manoj; Mal, Gorakh; Singh, Birbal

    2017-03-01

    This study reports structural modeling, molecular dynamics profiling of hypothetical proteins in Chlamydia abortus genome database. The hypothetical protein sequences were extracted from C. abortus LLG Genome Database for functional elucidation using in silico methods. Fifty-one proteins with their roles in defense, binding and transporting other biomolecules were unraveled. Forty-five proteins were found to be nonhomologous to proteins present in hosts infected by C. abortus . Of these, 31 proteins were related to virulence. The structural modeling of two proteins, first, WP_006344020.1 (phosphorylase) and second, WP_006344325.1 (chlamydial protease/proteasome-like activity factor) were accomplished. The conserved active sites necessary for the catalytic function were analyzed. The finally concluded proteins are envisioned as possible targets for developing drugs to curtail chlamydial infections, however, and should be validated by molecular biological methods.

  1. I. Forensic data analysis by pattern recognition. Categorization of white bond papers by elemental composition. II. Source identification of oil spills by pattern recognition analysis of natural elemental composition. III. Improving the reliability of factor analysis of chemical measured analytical data by utilizing the measured analytical uncertainity. IV. Elucidating the structure of some clinical data

    International Nuclear Information System (INIS)

    Duewer, D.L.

    1977-01-01

    Pattern recognition techniques are applied to the analysis of white bond papers and the problem of determining the source of an oil spill. In each case, an elemental analysis by neutron activation is employed. For the determination of source of oil spills, the field sample was weathered prior to activation analysis. A procedure for including measured analytical uncertainty into data analysis methodology is discussed, with particular reference to factor analysis. The suitability of various dispersion matrices and matrix rank determination criteria for data having analytical uncertainty is investigated. A criterion useful for judging the number of factors insensitive to analytical uncertainty is presented. A model data structure for investigating the behavior of factor analysis techniques in a known, controlled manner is described and analyzed. A chemically interesting test data base having analytical uncertainty is analyzed and compared with the model data. The data structure of 22 blood constituents in three categories of liver disease (viral or toxic hepatitis, alcoholic liver diseases and obstructive processes) is studied using various statistical and pattern recognition techniques. Comparison of classification results on the original data, in combination with principal component analysis, suggests a possible underlying structure for the data. This model structure is tested by the application of two simple data transformations. Analysis of the transformed data appears to confirm that some basic understanding of the studied data has been achieved

  2. Structure elucidation of 3-[1-(6-methoxy-2-naphtyl)ethyl]-6-(2,4-dichlorophenyl)-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine, C23H18Cl2N4OS from synchrotron X-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gündoğdu, Gülsüm; Aytaç, Sevim Peri; Müller, Melanie; Tozkoparan, Birsen; Kaynak, Filiz Betül

    2017-12-01

    The 3-[1-(6-methoxy-2-naphtyl)ethyl]-6-(2,4-dichlorophenyl)-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine, C23H18Cl2N4OS compound was synthesized, as a member of the family of novel potential anticancer agents. The structure of the title compound was characterized by IR,1H-NMR, mass spectroscopy, and elemental analysis, previously. In this study, the crystal structure of this compound has been determined from synchrotron X-ray powder diffraction data. The crystal structure was solved by simulated annealing and the final structure was achieved by Rietveld refinement method using soft restrains on all interatomic bond lengths and angles. This compound crystallizes in space groupP21,Z= 2, with the unit-cell parametersa= 15.55645(11) Å,b= 8.61693(6) Å,c= 8.56702(6) Å,β= 104.3270(4)°, andV= 1112.68(1) Å3. In the crystal structure, strong C-H∙∙∙πand weak intermolecular hydrogen-bonding interactions link the molecules into a three-dimensional network. The molecules are in a head-to-head arrangement in the unit cell.

  3. Product ion isotopologue pattern: A tool to improve the reliability of elemental composition elucidations of unknown compounds in complex matrices.

    Science.gov (United States)

    Kaufmann, A; Walker, S; Mol, G

    2016-04-15

    Elucidation of the elemental compositions of unknown compounds (e.g., in metabolomics) generally relies on the availability of accurate masses and isotopic ratios. This study focuses on the information provided by the abundance ratio within a product ion pair (monoisotopic versus the first isotopic peak) when isolating and fragmenting the first isotopic ion (first isotopic mass spectrum) of the precursor. This process relies on the capability of the quadrupole within the Q Orbitrap instrument to isolate a very narrow mass window. Selecting only the first isotopic peak (first isotopic mass spectrum) leads to the observation of a unique product ion pair. The lighter ion within such an isotopologue pair is monoisotopic, while the heavier ion contains a single carbon isotope. The observed abundance ratio is governed by the percentage of carbon atoms lost during the fragmentation and can be described by a hypergeometric distribution. The observed carbon isotopologue abundance ratio (product ion isotopologue pattern) gives reliable information regarding the percentage of carbon atoms lost in the fragmentation process. It therefore facilitates the elucidation of the involved precursor and product ions. Unlike conventional isotopic abundances, the product ion isotopologue pattern is hardly affected by isobaric interferences. Furthermore, the appearance of these pairs greatly aids in cleaning up a 'matrix-contaminated' product ion spectrum. The product ion isotopologue pattern is a valuable tool for structural elucidation. It increases confidence in results and permits structural elucidations for heavier ions. This tool is also very useful in elucidating the elemental composition of product ions. Such information is highly valued in the field of multi-residue analysis, where the accurate mass of product ions is required for the confirmation process. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Elucidation of cladofulvin biosynthesis reveals a cytochrome P450 monooxygenase required for anthraquinone dimerization.

    Science.gov (United States)

    Griffiths, Scott; Mesarich, Carl H; Saccomanno, Benedetta; Vaisberg, Abraham; De Wit, Pierre J G M; Cox, Russell; Collemare, Jérôme

    2016-06-21

    Anthraquinones are a large family of secondary metabolites (SMs) that are extensively studied for their diverse biological activities. These activities are determined by functional group decorations and the formation of dimers from anthraquinone monomers. Despite their numerous medicinal qualities, very few anthraquinone biosynthetic pathways have been elucidated so far, including the enzymatic dimerization steps. In this study, we report the elucidation of the biosynthesis of cladofulvin, an asymmetrical homodimer of nataloe-emodin produced by the fungus Cladosporium fulvum A gene cluster of 10 genes controls cladofulvin biosynthesis, which begins with the production of atrochrysone carboxylic acid by the polyketide synthase ClaG and the β-lactamase ClaF. This compound is decarboxylated by ClaH to yield emodin, which is then converted to chrysophanol hydroquinone by the reductase ClaC and the dehydratase ClaB. We show that the predicted cytochrome P450 ClaM catalyzes the dimerization of nataloe-emodin to cladofulvin. Remarkably, such dimerization dramatically increases nataloe-emodin cytotoxicity against mammalian cell lines. These findings shed light on the enzymatic mechanisms involved in anthraquinone dimerization. Future characterization of the ClaM enzyme should facilitate engineering the biosynthesis of novel, potent, dimeric anthraquinones and structurally related compound families.

  5. [Neuropsychological approach to elucidating delusion and psychotic symptoms].

    Science.gov (United States)

    Kato, Motoichiro

    2012-01-01

    Neuropsychological symptom-oriented approach is a critical method to elucidate delusion and psychotic symptoms in patients with focal brain damages and schizophrenia. In Capgras delusion (CD), the delusional misidentification of familiar people disguised as others, the patients with right amygdala damage and bilateral ventromedial prefrontal lesions have a deficient or reduced emotional valence of the person with intact configurational processes of the face. Reduplicative paramnesia (RP) is a specific phenomenon characterized by subjective certainty that a familiar place or person has been duplicated. Clinical evidences indicated that the patient with RP following right prefrontal damages showed the lack of emotional valence for the present hospital. This abnormal sense of familiarity triggered the deficits of the orientation of self to the outside world, that is, double orientation, resulting in the development of geographical reduplicative paramnesia. In line with the pathogenesis of CD and RP after brain damages, the delusion in schizophrenia may have a germ as developmental origins, which include the aberrant or salient perceptual experiences and abnormal sense of agency, and might be further aggravated by the impairment of causal reasoning process such as the jumping-to-conclusions bias.

  6. Elucidating high-dimensional cancer hallmark annotation via enriched ontology.

    Science.gov (United States)

    Yan, Shankai; Wong, Ka-Chun

    2017-09-01

    Cancer hallmark annotation is a promising technique that could discover novel knowledge about cancer from the biomedical literature. The automated annotation of cancer hallmarks could reveal relevant cancer transformation processes in the literature or extract the articles that correspond to the cancer hallmark of interest. It acts as a complementary approach that can retrieve knowledge from massive text information, advancing numerous focused studies in cancer research. Nonetheless, the high-dimensional nature of cancer hallmark annotation imposes a unique challenge. To address the curse of dimensionality, we compared multiple cancer hallmark annotation methods on 1580 PubMed abstracts. Based on the insights, a novel approach, UDT-RF, which makes use of ontological features is proposed. It expands the feature space via the Medical Subject Headings (MeSH) ontology graph and utilizes novel feature selections for elucidating the high-dimensional cancer hallmark annotation space. To demonstrate its effectiveness, state-of-the-art methods are compared and evaluated by a multitude of performance metrics, revealing the full performance spectrum on the full set of cancer hallmarks. Several case studies are conducted, demonstrating how the proposed approach could reveal novel insights into cancers. https://github.com/cskyan/chmannot. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Elucidation of polymer induced DNA condensation. Visualisation at the single molecular level

    International Nuclear Information System (INIS)

    Martin, Alison Laura

    2002-01-01

    DNA condensation is a phenomenon that has stimulated interest from biologists, physicists, and polymer chemists for decades. At the cellular level, this process is key to the packing of DNA within the nuclear envelope, and the exposure of the appropriate nucleic acid sequences in order for transcription to occur, and proteins to be produced. The advent of gene therapy has led to an invigoration of this subject area. In order to successfully deliver to, and transfect target cells, many delivery vectors condense the therapeutic DNA into small compact particles. The nature of these particles have a considerable influence on the ultimate expression of the administered nucleic acid material. In addition, at its most fundamental, DNA itself is a classical polyelectrolyte polymer, the behaviour of which has applicability to other charged polymeric systems. There are two core interwound themes to this investigation; the visualisation of DNA condensate morphology at ultra-resolution, and the elucidation of the mechanisms of formation of these structures. The technique of atomic force microscopy is central to these investigations. Methodologies have been devised allowing the visualisation of the tertiary structure and conformational behaviour of individual DNA condensates in near in situ conditions. Condensation of the nucleic acid material has been induced by two classes of cation; small molecular cations, like those found within eukaryotic cells, and a range of cationic polymers. The cationic polymers investigated all have considerable potential as gene delivery vectors. The resultant DNA condensates have been assessed and contrasted in terms of their tertiary morphology, lateral dimensions, and structural volume. Assessments have also been made regarding the influence of the molecular architecture of the cationic moiety and the nature of the input nucleic acid material on the resultant DNA condensates. With regard to the elucidation of the mechanisms of DNA condensate

  8. Thyrotropin serum levels are differentially associated with biochemical markers of bone turnover and stiffness in women and men: results from the SHIP cohorts.

    Science.gov (United States)

    Tsourdi, E; Wallaschofski, H; Rauner, M; Nauck, M; Pietzner, M; Rettig, R; Ittermann, T; Völzke, H; Völker, U; Hofbauer, L C; Hannemann, A

    2016-02-01

    In two large German population-based cohorts, we showed positive associations between serum thyrotropin (TSH) concentrations and the Fracture Risk Assessment score (FRAX) in men and positive associations between TSH concentrations and bone turnover markers in women. The role of thyroid hormones on bone stiffness and turnover is poorly defined. Existing studies are confounded by differences in design and small sample size. We assessed the association between TSH serum concentrations and bone stiffness and turnover in the SHIP cohorts, which are two population-based cohorts from a region in Northern Germany comprising 2654 men and women and 3261 men and women, respectively. We calculated the bone stiffness index using quantitative ultrasound (QUS) at the calcaneus, employed FRAX score for assessment of major osteoporotic fractures, and measured bone turnover markers, N-terminal propeptide of type I procollagen (P1NP), bone-specific alkaline phosphatase (BAP), osteocalcin, and type I collagen cross-linked C-telopeptide (CTX) in all subjects and sclerostin in a representative subgroup. There was no association between TSH concentrations and the stiffness index in both genders. In men, TSH correlated positively with the FRAX score both over the whole TSH range (p < 0.01) and within the reference TSH range (p < 0.01). There were positive associations between TSH concentrations and P1NP, BAP, osteocalcin, and CTX (p < 0.01) in women but not in men. There was no significant association between TSH and sclerostin levels. TSH serum concentrations are associated with gender-specific changes in bone turnover and stiffness.

  9. Radioiodine Thyroid Remnant Ablation after Recombinant Human Thyrotropin or Thyroid Hormone Withdrawal in Patients with High-Risk Differentiated Thyroid Cancer

    Directory of Open Access Journals (Sweden)

    Fabián Pitoia

    2012-01-01

    Full Text Available To supplement limited relevant literature, we retrospectively compared ablation and disease outcomes in high-risk differentiated thyroid carcinoma (DTC patients undergoing radioiodine thyroid remnant ablation aided by recombinant human thyrotropin (rhTSH versus thyroid hormone withdrawal/withholding (THW. Our cohort was 45 consecutive antithyroglobulin antibody- (TgAb- negative, T3-T4/N0-N1-Nx/M0 adults ablated with high activities at three referral centers. Ablation success comprised negative (<1 μg/L stimulated serum thyroglobulin (Tg and TgAb, with absent or <0.1% scintigraphic thyroid bed uptake. “No evidence of disease” (NED comprised negative unstimulated/stimulated Tg and no suspicious neck ultrasonography or pathological imaging or biopsy. “Persistent disease” was failure to achieve NED, “recurrence,” loss of NED status. rhTSH patients (n=18 were oftener ≥45 years old and higher stage (P=0.01, but otherwise not different than THW patients (n=27 at baseline. rhTSH patients were significantly oftener successfully ablated compared to THW patients (83% versus 67%, P<0.02. After respective 3.3 yr and 4.5 yr mean follow-ups (P=0.02, NED was achieved oftener (72% versus 59% and persistent disease was less frequent in rhTSH patients (22% versus 33% (both comparisons P=0.03. rhTSH stimulation is associated with at least as good outcomes as is THW in ablation of high-risk DTC patients.

  10. Radioiodine thyroid remnant ablation after recombinant human thyrotropin or thyroid hormone withdrawal in patients with high-risk differentiated thyroid cancer.

    Science.gov (United States)

    Pitoia, Fabián; Marlowe, Robert J; Abelleira, Erika; Faure, Eduardo N; Bueno, Fernanda; Schwarzstein, Diego; Lutfi, Rubén Julio; Niepomniszcze, Hugo

    2012-01-01

    To supplement limited relevant literature, we retrospectively compared ablation and disease outcomes in high-risk differentiated thyroid carcinoma (DTC) patients undergoing radioiodine thyroid remnant ablation aided by recombinant human thyrotropin (rhTSH) versus thyroid hormone withdrawal/withholding (THW). Our cohort was 45 consecutive antithyroglobulin antibody- (TgAb-) negative, T3-T4/N0-N1-Nx/M0 adults ablated with high activities at three referral centers. Ablation success comprised negative (<1 μg/L) stimulated serum thyroglobulin (Tg) and TgAb, with absent or <0.1% scintigraphic thyroid bed uptake. "No evidence of disease" (NED) comprised negative unstimulated/stimulated Tg and no suspicious neck ultrasonography or pathological imaging or biopsy. "Persistent disease" was failure to achieve NED, "recurrence," loss of NED status. rhTSH patients (n = 18) were oftener ≥45 years old and higher stage (P = 0.01), but otherwise not different than THW patients (n = 27) at baseline. rhTSH patients were significantly oftener successfully ablated compared to THW patients (83% versus 67%, P < 0.02). After respective 3.3 yr and 4.5 yr mean follow-ups (P = 0.02), NED was achieved oftener (72% versus 59%) and persistent disease was less frequent in rhTSH patients (22% versus 33%) (both comparisons P = 0.03). rhTSH stimulation is associated with at least as good outcomes as is THW in ablation of high-risk DTC patients.

  11. Thyroid remnant ablation success and disease outcome in stage III or IV differentiated thyroid carcinoma: recombinant human thyrotropin versus thyroid hormone withdrawal.

    Science.gov (United States)

    Vallejo Casas, Juan A; Mena Bares, Luisa M; Gálvez Moreno, Maria A; Moreno Ortega, Estefanía; Marlowe, Robert J; Maza Muret, Francisco R; Albalá González, María D

    2016-06-01

    Most publications to date compare outcomes after post-surgical thyroid remnant ablation stimulated by recombinant human thyrotropin (rhTSH) versus thyroid hormone withholding/withdrawal (THW) in low-recurrence risk differentiated thyroid carcinoma (DTC) patients. We sought to perform this comparison in high-risk patients. We retrospectively analyzed ~9-year single-center experience in 70 consecutive adults with initial UICC (Union for International Cancer Control) stage III/IV, M0 DTC undergoing rhTSH-aided (N.=54) or THW-aided (N.=16) high-activity ablation. Endpoints included ablation success and DTC outcome. Assessed ≥1 year post-ablation, ablation success comprised a) no visible scintigraphic thyroid bed uptake or pathological extra-thyroidal uptake; b) undetectable stimulated serum thyroglobulin (Tg) without interfering autoantibodies; c) both criteria. DTC outcome, determined at the latest visit, comprised either 1) "no evidence of disease" (NED): undetectable Tg, negative Tg autoantibodies, negative most recent whole-body scan, no suspicious findings clinically, on neck ultrasonography, or on other imaging; 2) persistent disease: failure to attain NED; or 3) recurrence: loss of NED. After the first ablative activity, ablation success by scintigraphic plus biochemical criteria was 64.8% in rhTSH patients, 56.3% in THW patients (P=NS). After 3.5-year versus 6.2-year median follow-up (P<0.05), DTC outcomes were NED, 85.2%, persistent disease, 13.0%, recurrence, 1.9%, in the rhTSH group and NED, 87.5%, persistent or recurrent disease, 6.3% each, in the THW group (P=NS). In patients with initial stage III/IV, M0 DTC, rhTSH-aided and THW-assisted ablation were associated with comparable remnant eradication or DTC cure rates.

  12. Tripeptide amide L-pyroglutamyl-histidyl-L-prolineamide (L-PHP-thyrotropin-releasing hormone, TRH) promotes insulin-producing cell proliferation.

    Science.gov (United States)

    Luo, LuGuang; Luo, John Z Q; Jackson, Ivor

    2013-02-01

    A very small tripeptide amide L-pyroglutamyl-L-histidyl-L-prolineamide (L-PHP, Thyrotropin-Releasing Hormone, TRH), was first identified in the brain hypothalamus area. Further studies found that L-PHP was expressed in pancreas. The biological role of pancreatic L-PHP is still not clear. Growing evidence indicates that L-PHP expression in the pancreas may play a pivotal role for pancreatic development in the early prenatal period. However, the role of L-PHP in adult pancreas still needs to be explored. L-PHP activation of pancreatic β cell Ca2+ flow and stimulation of β-cell insulin synthesis and release suggest that L-PHP involved in glucose metabolism may directly act on the β cell separate from any effects via the central nervous system (CNS). Knockout L-PHP animal models have shown that loss of L-PHP expression causes hyperglycemia, which cannot be reversed by administration of thyroid hormone, suggesting that the absence of L-PHP itself is the cause. L-PHP receptor type-1 has been identified in pancreas which provides a possibility for L-PHP autocrine and paracrine regulation in pancreatic function. During pancreatic damage in adult pancreas, L-PHP may protect beta cell from apoptosis and initiate its regeneration through signal pathways of growth hormone in β cells. L-PHP has recently been discovered to affect a broad array of gene expression in the pancreas including growth factor genes. Signal pathways linked between L-PHP and EGF receptor phosphorylation suggest that L-PHP may be an important factor for adult β-cell regeneration, which could involve adult stem cell differentiation. These effects suggest that L-PHP may benefit pancreatic β cells and diabetic therapy in clinic.

  13. Presence of Epstein-Barr virus-infected B lymphocytes with thyrotropin receptor antibodies on their surface in Graves' disease patients and in healthy individuals.

    Science.gov (United States)

    Nagata, Keiko; Higaki, Katsumi; Nakayama, Yuji; Miyauchi, Hiromi; Kiritani, Yui; Kanai, Kyosuke; Matsushita, Michiko; Iwasaki, Takeshi; Sugihara, Hirotsugu; Kuwamoto, Satoshi; Kato, Masako; Murakami, Ichiro; Nanba, Eiji; Kimura, Hiroshi; Hayashi, Kazuhiko

    2014-05-01

    Graves' disease is an autoimmune hyperthyroidism caused by thyrotropin receptor antibodies (TRAbs). Because Epstein-Barr virus (EBV) persists in B cells and is occasionally reactivated, we hypothesized that EBV contributes to TRAbs production in Graves' disease patients by stimulating the TRAbs-producing B cells. In order for EBV to stimulate antibody-producing cells, EBV must be present in those cells but that have not yet been observed. We examined whether EBV-infected (EBV(+)) B cells with TRAbs on their surface (TRAbs(+)) as membrane immunoglobulin were present in peripheral blood of Graves' disease patients. We analyzed cultured or non-cultured peripheral blood mononuclear cells (PBMCs) from 13 patients and 11 healthy controls by flow-cytometry and confocal laser microscopy, and confirmed all cultured PBMCs from 8 patients really had TRAbs(+) EBV(+) double positive cells. We unexpectedly detected TRAbs(+) cells in all healthy controls, and TRAbs(+) EBV(+) double positive cells in all cultured PBMC from eight healthy controls. The frequency of TRAbs(+) cells in cultured PBMCs was significantly higher in patients than in controls (p = 0.021). In this study, we indicated the presence of EBV-infected B lymphocytes with TRAbs on their surface, a possible player of the production of excessive TRAbs, the causative autoantibody for Graves' disease. This is a basic evidence for our hypothesis that EBV contributes to TRAbs production in Graves' disease patients. Our results further suggest that healthy controls have the potential for TRAbs production. This gives us an important insight into the pathogenesis of Graves' disease.

  14. Determination of congenital hypothyroidism in neonatal by immunoradiometric assays of thyrotropin; Determinacion de hipotiroidismo congenito en neonatos por analisis inmunoradiometrico de tirotrofina

    Energy Technology Data Exchange (ETDEWEB)

    Contreras P, E

    1998-06-01

    The congenital hypothyroidism is the endocrine illness more frequent of the childhood, it is the one that produce the devastating effects on the growth and the development. It represent one of the few causes of mental delay that it could be prevented if it is diagnosed and treaty on time. The infants affected with congenital hypothyroidism, could be detected for the apparent presence of some physical abnormalities, which comes the first days of the birth. Unfortunately, in the moment in which the classical manifestations are made present, it is very probable that cerebral damage already exists, for what the affected children should be tried before the three months of life administering them thyroid hormones. In Mexico the incidence of the congenital hypothyroidism is of one for each 1612 births for that is very important in the area of Public Health diagnose in early form and with certainty the congenital hypothyroidism. The TSH hormone or thyrotropin is formed in the hypophysis and intervenes in the synthesis of the thyroid hormones (T3, T4) when the concentration of these is adapted, the formation of TSH is inhibited, for that upon lacking the thyroid hormones the concentration of TSH in the blood is high. For these reasons the shot metabolic state of a newborn could be determined, quantifying the TSH in blood obtained by heel stab of the neonatal, or in coming blood from the umbilical cord, after 48 hours of being born. However because the TSH is similar to other hormones and is in extremely low concentrations, it is made necessary appeal analytic techniques of very sensitive and specific laboratory like the Immunoradiometric assays (Irma) in order to could determine the levels of this hormone in the blood. (Author).

  15. Food-intake dysregulation in type 2 diabetic Goto-Kakizaki rats: hypothesized role of dysfunctional brainstem thyrotropin-releasing hormone and impaired vagal output.

    Science.gov (United States)

    Zhao, K; Ao, Y; Harper, R M; Go, V L W; Yang, H

    2013-09-05

    Thyrotropin-releasing hormone (TRH), a neuropeptide contained in neural terminals innervating brainstem vagal motor neurons, enhances vagal outflow to modify multisystemic visceral functions and food intake. Type 2 diabetes (T2D) and obesity are accompanied by impaired vagal functioning. We examined the possibility that impaired brainstem TRH action may contribute to the vagal dysregulation of food intake in Goto-Kakizaki (GK) rats, a T2D model with hyperglycemia and impaired central vagal activation by TRH. Food intake induced by intracisternal injection of TRH analog was reduced significantly by 50% in GK rats, compared to Wistar rats. Similarly, natural food intake in the dark phase or food intake after an overnight fast was reduced by 56-81% in GK rats. Fasting (48h) and refeeding (2h)-associated changes in serum ghrelin, insulin, peptide YY, pancreatic polypeptide and leptin, and the concomitant changes in orexigenic or anorexigenic peptide expression in the brainstem and hypothalamus, all apparent in Wistar rats, were absent or markedly reduced in GK rats, with hormone release stimulated by vagal activation, such as ghrelin and pancreatic polypeptide, decreased substantially. Fasting-induced Fos expression accompanying endogenous brainstem TRH action decreased by 66% and 91%, respectively, in the nucleus tractus solitarius (NTS) and the dorsal motor nucleus of the vagus (DMV) in GK rats, compared to Wistar rats. Refeeding abolished fasting-induced Fos-expression in the NTS, while that in the DMV remained in Wistar but not GK rats. These findings indicate that dysfunctional brainstem TRH-elicited vagal impairment contributes to the disturbed food intake in T2D GK rats, and may provide a pathophysiological mechanism which prevents further weight gain in T2D and obesity. Published by Elsevier Ltd.

  16. Effects of sodium ions on rat thyrocyte (FRTL-5 cells) swelling- and thyrotropin-activated taurine efflux dependent on cAMP and Epac.

    Science.gov (United States)

    Fugelli, Kjell

    2016-03-01

    Cellular osmolyte release is important in preventing water accumulation and swelling. However, the signaling pathways that detect volume increase and activate solute efflux are still not fully understood. We investigated efflux activation of the osmolyte taurine which is actively accumulated in rat thyrocytes (FRTL-5). Efflux of accumulated [(3)H]taurine was stimulated by cellular swelling and thyrotropin (TSH). These effects were significantly diminished in cells having reduced TSH receptor concentrations. Phosphodiesterase inhibitors (IBMX, Rolipram) enhanced both responses. An analog of forskolin (FSK; 7-deacetyl-7-[O-(N-methylpiperazino)-γ-butyryl] dihydrochloride) and an analog of cAMP, specific for activating exchange protein activated directly by cAMP (Epac; 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester), significantly stimulated [(3)H]taurine efflux. A cAMP analog specific for activating protein kinase A (PKA; N6-benzoyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester) had no significant stimulatory effect on [(3)H]taurine efflux rate. The amiloride analog, 5-(N-ethyl-N-isopropyl)-amiloride, which inhibits a TSH-stimulated Na(+)/H(+) exchanger, enhanced (100 %) and ouabain inhibited (50 %) the TSH-stimulated [(3)H]taurine efflux rate. The effect of FSK on efflux was strongly potentiated by Na(+)-free iso-osmotic conditions and by osmolality/cell volume that affected also the db-cAMP-stimulated efflux. The TSH receptors and downstream elements of the signaling pathway comprising adenylyl cyclase, cAMP and Epac appeared to mediate the hormone-induced signal for [(3)H]taurine efflux from FRTL-5 cells. With less evidence, the cell volume/osmolality-induced [(3)H]taurine efflux cascade appeared to share some of the hormone signaling elements and to modulate the hormone signaling pathway at two levels through cellular Na(+).

  17. Lanthanide-cyclodextrin complexes as probes for elucidating optical purity by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, T.J.; Bogyo, M.S.; Lebeau, E.L. (Bates College, Lewiston, ME (United States))

    1994-06-01

    A multidentate ligand is bonded to cyclodextrins by the reaction of diethylenetriaminepentaacetic dianhydride with 6-mono- and 2-mono(ethylenediamine) derivatives of cyclodextrin. Adding Dy(III) to the cyclodextrin derivatives enhances the enantiomeric resolution in the [sup 1]H NMR spectra of carbionoxamine maleate, doxylamine succinate, pheniramine maleate, propranolol hydrochloride, and tryptophan. The enhancement is more pronounced with the secondary derivative. The Dy(III)-induced shifts can be used to elucidate the geometry of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shifts are reported for complexes of aspartame, tryptophan, propranolol, and 1-anilino-8-naphthalenesulfonate with cyclodextrins, and the relative magnitudes of the shifts agree with previously reported structures of the complexes. 37 refs., 9 figs., 5 tabs.

  18. Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling

    Science.gov (United States)

    Grace, Joseph M.; Verseux, Cyprien; Gentry, Diana; Moffet, Amy; Thayabaran, Ramanen; Wong, Nathan; Rothschild, Lynn

    2013-01-01

    The adaptation of micro-organisms to their environments is a complex process of interaction between the pressures of the environment and of competition. Reducing this multifactorial process to environmental exposure in the laboratory is a common tool for elucidating individual mechanisms of evolution, such as mutation rates. Although such studies inform fundamental questions about the way adaptation and even speciation occur, they are often limited by labor-intensive manual techniques. Current methods for controlled study of microbial adaptation limit the length of time, the depth of collected data, and the breadth of applied environmental conditions. Small idiosyncrasies in manual techniques can have large effects on outcomes; for example, there are significant variations in induced radiation resistances following similar repeated exposure protocols. We describe here a project under development to allow rapid cycling of multiple types of microbial environmental exposure. The system allows continuous autonomous monitoring and data collection of both single species and sampled communities, independently and concurrently providing multiple types of controlled environmental pressure (temperature, radiation, chemical presence or absence, and so on) to a microbial community in dynamic response to the ecosystem's current status. When combined with DNA sequencing and extraction, such a controlled environment can cast light on microbial functional development, population dynamics, inter- and intra-species competition, and microbe-environment interaction. The project's goal is to allow rapid, repeatable iteration of studies of both natural and artificial microbial adaptation. As an example, the same system can be used both to increase the pH of a wet soil aliquot over time while periodically sampling it for genetic activity analysis, or to repeatedly expose a culture of bacteria to the presence of a toxic metal, automatically adjusting the level of toxicity based on the

  19. Commentary: Elucidating the Neural Correlates of Early Childhood Memory

    Science.gov (United States)

    Mullally, Sinead L.

    2015-01-01

    Both episodic memory and the key neural structure believed to support it, namely the hippocampus, are believed to undergo protracted periods of postnatal developmental. Critically however, the hippocampus is comprised of distinct subfields and circuits, and these circuits appear to mature at different rates (Lavenex and Banta Lavenex, 2013).…

  20. Elucidating dominant pathways of the nano-particle self-assembly process.

    Science.gov (United States)

    Zeng, Xiangze; Li, Bin; Qiao, Qin; Zhu, Lizhe; Lu, Zhong-Yuan; Huang, Xuhui

    2016-09-14

    Self-assembly processes play a key role in the fabrication of functional nano-structures with widespread application in drug delivery and micro-reactors. In addition to the thermodynamics, the kinetics of the self-assembled nano-structures also play an important role in determining the formed structures. However, as the self-assembly process is often highly heterogeneous, systematic elucidation of the dominant kinetic pathways of self-assembly is challenging. Here, based on mass flow, we developed a new method for the construction of kinetic network models and applied it to identify the dominant kinetic pathways for the self-assembly of star-like block copolymers. We found that the dominant pathways are controlled by two competing kinetic parameters: the encounter time Te, characterizing the frequency of collision and the transition time Tt for the aggregate morphology change from rod to sphere. Interestingly, two distinct self-assembly mechanisms, diffusion of an individual copolymer into the aggregate core and membrane closure, both appear at different stages (with different values of Tt) of a single self-assembly process. In particular, the diffusion mechanism dominates the middle-sized semi-vesicle formation stage (with large Tt), while the membrane closure mechanism dominates the large-sized vesicle formation stage (with small Tt). Through the rational design of the hydrophibicity of the copolymer, we successfully tuned the transition time Tt and altered the dominant self-assembly pathways.

  1. Diagnostic value of recombinant human thyrotropin-stimulated ¹²³I whole-body scintigraphy in the follow-up of patients with differentiated thyroid cancer.

    Science.gov (United States)

    Alzahrani, Ali S; AlShaikh, OmAlkhaire; Tuli, Mahmoud; Al-Sugair, Abdulaziz; Alamawi, Reem; Al-Rasheed, Maha M

    2012-03-01

    Published data on recombinant human thyrotropin- (rhTSH-) stimulated iodine-123 (¹²³I) diagnostic whole-body scintigraphy (DxWBS) in differentiated thyroid cancer (DTC) surveillance after initial treatment are limited. We sought to evaluate this modality's diagnostic value in this setting. We retrospectively compared rhTSH-stimulated ¹²³I DxWBS results with DTC status concurrently determined by stimulated serum thyroglobulin (Tg) measurement, neck ultrasonography, and other imaging studies. Disease was considered present based on stimulated Tg level ≥1 μg/L without interfering Tg autoantibodies with or without positive imaging or biopsy-proven DTC. We also compared scan positivity and disease detection rates of rhTSH-stimulated DxWBS scans obtained with ¹²³I with those acquired with iodine-131 (¹³¹I) during the same period. The sample comprised 105 consecutive totally thyroidectomized patients undergoing rhTSH-aided DxWBS with I-123 (n = 67) or with ¹³¹I (n = 38) for diagnostic follow-up. rhTSH, 0.9 mg/d, was injected intramuscularly on 2 consecutive days. Oral diagnostic activities of 5 to 10 mCi (185-370 MBq) ¹²³I or 3 mCi (111 MBq) ¹³¹I were given on the third day. DxWBS was performed 24 hours (¹²³I) or 48 to 72 hours (¹³¹I) later. rhTSH-aided ¹²³I DxWBS scans showed 35.3% sensitivity, 98.0% specificity, 85.7% positive predictive value, and 81.6% negative predictive value. rhTSH-stimulated ¹²³I and ¹³¹I DxWBS did not differ in scan positivity (10.4% vs. 13.2%, P = 0.75) or disease detection rates (35.3% vs. 27.8%, P = 1.00). In DTC, rhTSH-aided ¹²³I DxWBS achieves comparable results in diagnostic follow-up with those of rhTSH-aided ¹³¹I DxWBS. Future studies should address the preablation setting and scan activity and timing.

  2. Effects of forced swimming stress on thyroid function, pituitary thyroid-stimulating hormone and hypothalamus thyrotropin releasing hormone expression in adrenalectomy Wistar rats.

    Science.gov (United States)

    Sun, Qiuyan; Liu, Aihua; Ma, Yanan; Wang, Anyi; Guo, Xinhong; Teng, Weiping; Jiang, Yaqiu

    2016-11-01

    In order to study the impact that is imposed on the hypothalamic-pituitary-thyroid (HPT) axis of adrenalectomy male Wistar rats by stress caused by swimming, the blood level of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH), the expression of TSHβ mRNA at the pituitary and thyrotropin releasing hormone (TRH) expression at the paraventricular nucleus (PVN) were measured. A total of 50 male Wistar rats of 6-8 weeks of age and with an average weight of 190-210 grams were randomly divided into the following two groups: The surgical (without adrenal glands) and non-surgical (adrenalectomy) group. These two groups were then divided into the following five groups, according to the time delay of sacrifice following forced swim (10 min, 2 h, 12 h and 24 h) and control (not subjected to swimming) groups. A bilateral adrenalectomy animal model was established. Serum TSH in the blood was measurement by chemiluminescent immunoassay, and cerebrum tissue were excised for the measurement of TRH expression using an immunohistochemistry assay. In addition, pituitaries were excised for the extraction of total RNA. Finally, reverse transcription-quantitative polymerase chain reaction was performed for quantitation of TSHβ. Following swimming, the serum T3, T4 and TSH, the TSHβ mRNA expression levels in the pituitary and the TRH expression in the PVN of the surgical group were gradually increased. In the non-surgical group, no significant differences were observed in the serum T3, T4 and TSH levels compared with the control group. The TSHβ mRNA expression at the pituitary showed a similar result. Furthermore, the TRH expression at PVN was gradually increased and stress from swimming could increase the blood T4, T3 and TSH levels, TSHβ mRNA expression at the pituitary and TRH expression at the PVN in adrenalectomy Wistar rats. Moreover, the index in the surgical group changed significantly compared with the non-surgical group. In conclusion, the results

  3. Structure elucidation and stereoselective total synthesis of pavettamine, the causal agent of gousiekte

    CSIR Research Space (South Africa)

    Bode, ML

    2010-03-01

    Full Text Available resolution fast atom bombardment (FAB) mass spectra were recorded by Dr. L. Fourie, University of Potchefstroom, on a VG 7070-E spectrometer (Xe beam, m-nitrobenzyl alcohol matrix, detection of positive ions with m/z>99). Electrospray-mass spectrometry (ES...), 45.46T (C-1), 31.46T and 31.16T (C-3), 30.00Q ((CH3)2C), 28.44Q (C(CH3)3), 19.87Q and 19.71Q ((CH3)2C). HRMS (FAB): m/z 631.4042 (M+); calcd for C31H57N3O10: 631.4044. 3.5 Diethyl (2S)-malate (4) (2S)-Malic acid (100 g, 0.746 mol) was suspended...

  4. Experimental observations elucidating the mechanisms of structural bcc-hcp transformations in ?-Ti alloys

    NARCIS (Netherlands)

    Van Bohemen, S.M.C.; Sietsma, J.; Van der Zwaag, S.

    2006-01-01

    The formation mechanisms of two hcp ? phase morphologies in Ti-4.5Fe-6.8Mo-1.5Al have been investigated by optical microscopy (OM), atomic force microscopy (AFM), electron probe microanalysis (EPMA) and dilatometry. At relatively high temperatures primary ? forms predominantly on prior bcc ? grain

  5. Isolation and structural elucidation of tiamulin metabolites formed in liver microsomes of pigs

    DEFF Research Database (Denmark)

    Lykkeberg, Anne Kruse; Cornett, Claus; Halling-Sørensen, Bent

    2006-01-01

    Although the antimicrobial tiamulin is extensively metabolized in pigs, the metabolism is not well investigated. In this work the NADPH dependent metabolism of tiamulin in liver microsomes from pigs has been studied. The tiamulin metabolites formed in the incubations were analysed using LC-MS, an...... 20% of tiamulin was deethylated, 10% was hydroxylated in the 2beta-position and 7% was hydroxylated in the 8alpha-position. About 40% of tiamulin was metabolized during the incubation conditions used. The protein precipitation in the incubations was performed using perchloric acid...

  6. Isolation, structural elucidation and immunomodulatory activity of fructans from aged garlic extract.

    Science.gov (United States)

    Chandrashekar, Puthanapura M; Prashanth, Keelara V Harish; Venkatesh, Yeldur P

    2011-02-01

    Traditionally, garlic (Allium sativum) is known to be a significant immune booster. Aged garlic extract (AGE) possesses superior immunomodulatory effects than raw garlic; these effects are attributed to the transformed organosulfur compounds. AGE is also known to contain fructans; the amount of fructans in AGE represents a small fraction (0.22%) of the total fructans in raw garlic. In order to evaluate the biological activity of fructans present in AGE, both high molecular weight (>3.5 kDa; HF) and low molecular weight (immunomodulators such as zymosan and mannan. This study clearly demonstrates that garlic fructans also contribute to the immunomodulatory properties of AGE, and is the first such study on the biological effects of garlic fructans. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. PMA-PhyloChip DNA Microarray to Elucidate Viable Microbial Community Structure

    Science.gov (United States)

    Venkateswaran, Kasthuri J.; Stam, Christina N.; Andersen, Gary L.; DeSantis, Todd

    2011-01-01

    Since the Viking missions in the mid-1970s, traditional culture-based methods have been used for microbial enumeration by various NASA programs. Viable microbes are of particular concern for spacecraft cleanliness, for forward contamination of extraterrestrial bodies (proliferation of microbes), and for crew health/safety (viable pathogenic microbes). However, a "true" estimation of viable microbial population and differentiation from their dead cells using the most sensitive molecular methods is a challenge, because of the stability of DNA from dead cells. The goal of this research is to evaluate a rapid and sensitive microbial detection concept that will selectively estimate viable microbes. Nucleic acid amplification approaches such as the polymerase chain reaction (PCR) have shown promise for reducing time to detection for a wide range of applications. The proposed method is based on the use of a fluorescent DNA intercalating agent, propidium monoazide (PMA), which can only penetrate the membrane of dead cells. The PMA-quenched reaction mixtures can be screened, where only the DNA from live cells will be available for subsequent PCR reaction and microarray detection, and be identified as part of the viable microbial community. An additional advantage of the proposed rapid method is that it will detect viable microbes and differentiate from dead cells in only a few hours, as opposed to less comprehensive culture-based assays, which take days to complete. This novel combination approach is called the PMA-Microarray method. DNA intercalating agents such as PMA have previously been used to selectively distinguish between viable and dead bacterial cells. Once in the cell, the dye intercalates with the DNA and, upon photolysis under visible light, produces stable DNA adducts. DNA cross-linked in this way is unavailable for PCR. Environmental samples suspected of containing a mixture of live and dead microbial cells/spores will be treated with PMA, and then incubated in the dark. Thereafter, the sample is exposed to visible light for five minutes, so that the DNA from dead cells will be cross-linked. Following this PMA treatment step, the sample is concentrated by centrifugation and washed (to remove excessive PMA) before DNA is extracted. The 16S rRNA gene fragments will be amplified by PCR to screen the total microbial community using PhyloChip DNA microarray analysis. This approach will detect only the viable microbial community since the PMA intercalated DNA from dead cells would be unavailable for PCR amplification. The total detection time including PCR reaction for low biomass samples will be a few hours. Numerous markets may use this technology. The food industry uses spore detection to validate new alternative food processing technologies, sterility, and quality. Pharmaceutical and medical equipment companies also detect spores as a marker for sterility. This system can be used for validating sterilization processes, water treatment systems, and in various public health and homeland security applications.

  8. Structure Elucidation of Dimethylformamide-Solvated Alkylzinc Cations in the Gas Phase

    NARCIS (Netherlands)

    Dreiocker, F.; Oomens, J.; Meijer, Ajhm; Pickup, B. T.; Jackson, R. F. W.; Schafer, M.

    2010-01-01

    Organozinc iodides, useful for the synthesis of nonproteinogenic amino acids, are investigated in the gas phase by a combination of electrospray (ESI)-MS/MS, accurate ion mass measurements, and infrared multiphoton dissociation (IRMPD) spectroscopy employing a free electron laser. ESI allowed the

  9. Structure elucidation of dimethylformamide-solvated alkylzinc cations in the gas phase

    NARCIS (Netherlands)

    Dreiocker, F.; Oomens, J.; Meijer, A.J.H.M.; Pickup, B.T.; Jackson, R.F.W.; Schäfer, M.

    2010-01-01

    Organozinc iodides, useful for the synthesis of nonproteinogenic amino acids, are investigated in the gas phase by a combination of electrospray (ESI)-MS/MS, accurate ion mass measurements, and infrared multiphoton dissociation (IRMPD) spectroscopy employing a free electron laser. ESI allowed the

  10. Cannabis—XV . Pyrolysis of cannabidiol. Structure elucidation of four pyrolytic products

    NARCIS (Netherlands)

    Kuppers, F.J.E.M.; Bercht, C.A.L.; Salemink, C.A.; Lousberg, R.J.J.Ch.

    1975-01-01

    Pyrolysis of cannabidiol in nitrogen atmosphere affords at least six more products with longer GC-retention times than CBD, next to unconverted CBD. Two of these could be identified as Δ1(2)THC and CBN Two further products were investigated and their mass spectrometrical fragmentations and

  11. Elucidating the Structure-Activity Relationships of the Vasorelaxation and Antioxidation Properties of Thionicotinic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Virapong Prachayasittikul

    2010-01-01

    Full Text Available Nicotinic acid, known as vitamin B3, is an effective lipid lowering drug and intense cutaneous vasodilator. This study reports the effect of 2-(1-adamantylthionicotinic acid (6 and its amide 7 and nitrile analog 8 on phenylephrine-induced contraction of rat thoracic aorta as well as antioxidative activity. It was found that the tested thionicotinic acid analogs 6-8 exerted maximal vasorelaxation in a dose-dependent manner, but their effects were less than acetylcholine (ACh-induced nitric oxide (NO vasorelaxation. The vasorelaxations were reduced, apparently, in both NG-nitro-L-arginine methyl ester (L-NAME and indomethacin (INDO. Synergistic effects were observed in the presence of L-NAME plus INDO, leading to loss of vasorelaxation of both the ACh and the tested nicotinic acids. Complete loss of the vasorelaxation was noted under removal of endothelial cells. This infers that the vasorelaxations are mediated partially by endothelium-induced NO and prostacyclin. The thionicotinic acid analogs all exhibited antioxidant properties in both 2,2-diphenyl-1-picrylhydrazyl (DPPH and superoxide dismutase (SOD assays. Significantly, the thionicotinic acid 6 is the most potent vasorelaxant with ED50 of 21.3 nM and is the most potent antioxidant (as discerned from DPPH assay. Molecular modeling was also used to provide mechanistic insights into the vasorelaxant and antioxidative activities. The findings reveal that the thionicotinic acid analogs are a novel class of vasorelaxant and antioxidant compounds which have potential to be further developed as promising therapeutics.

  12. Structural elucidation of antihemorrhage drug molecule Diethylammonium 2,5-dihydroxybenzene sulfonate - an insilico approach

    Science.gov (United States)

    Kumar, S. Anil; Bhaskar, BL

    2018-02-01

    Ab-initio computational study of antihemorrhage drug molecule diethylammonium 2,5-dihydroxybenzene sulfonate, popularly known as ethamsylate, has been attempted using Gaussian 09. The optimized molecular geometry has been envisaged using density functional theory method at B3LYP/6-311 basis set. Different geometrical parameters like bond lengths and bond angles were computed and compared against the experimental results available in literature. Fourier transform infrared scanning of the title molecule was performed and vibrational frequencies were also computed using Gaussian software. The presence of O-H---O hydrogen bonds between C6H5O5S- anions and N-H---O hydrogen bonds between anion and cation is evident in the computational studies also. In general, satisfactory agreement of concordance has been observed between computational and experimental results.

  13. Structure-function elucidation of a new alpha-Conotoxin, Lo1a, from Conus longurionis.

    Digital Repository Service at National Institute of Oceanography (India)

    Lebbe, E.K.M.; Peigneur, S.; Maiti, M.; PrabhaDevi; Ravichandran, S.; Lescrinier, E.; Ulens, C.; Waelkens, E.; DeSouza, L.; Herdewijn, P.; Tytgat, J.

    membranes of certain neurons and the neuromuscular junction. Because nAChRs have an important role in regulating transmitter release, cell excitability, and neuronal integration, nAChR dysfunctions have been implicated in a variety of severe pathologies...

  14. Isolation and Structure Elucidation of Radical Scavengers from Thymus vulgaris Leaves

    NARCIS (Netherlands)

    Dapkevicius, A.; Beek, van T.A.; Lelyveld, G.P.; Veldhuizen, van A.; Groot, de Æ.; Linssen, J.P.H.; Venskutonis, R.

    2002-01-01

    2,2-Diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging activity-guided fractionation of a leaf extract of Thymus vulgaris led to the isolation of the radical scavengers rosmarinic acid 1, eriodictyol, taxifolin, luteolin 7-glucuronide, p-cymene 2,3-diol, p-cymene 2,3-diol 6-6'-dimer, carvacrol,

  15. Arohynapenes A and B, new anticoccidial agents produced by Penicillium sp. Taxonomy, fermentation, and structure elucidation.

    Science.gov (United States)

    Masuma, R; Tabata, N; Tomoda, H; Haneda, K; Iwai, Y; Omura, S

    1994-01-01

    Penicillium sp. FO-2295, a water isolate, was found to produce a series of new anticoccidial compounds. Two active compounds, designated arohynapenes A and B, were isolated from the fermentation broth of the producing strain by solvent extration and preparative HPLC. Arohynapene A was deduced to be (2E,4E)-5-(5-hydroxy-2,6,8-trimethyl-5,6,7,8-tetrahydronaphtale ne)-2,4- pentadienoic acid, and arohynapene B was (2E,4E)-5-(2-hydroxymethyl-6,8-dimethyl-5,6,7,8-tetrahydronapht alene)-2,4- pentadienoic acid. Arohynapenes inhibited the growth of Eimeria tenella in an in vitro assay using BHK-21 cells as a host. No schizont in the cells was observed at concentrations ranging above 35.0 microM and 7.0 microM for arohynapenes A and B, respectively.

  16. Study on a new antifungal antibiotic, yimeimycin--isolation, structure elucidation and biological activities

    International Nuclear Information System (INIS)

    Shi Yuefeng; Sang Jinlong; Zhu Lihong; Li Xiaohui; Wu Jian

    2004-01-01

    Strain HA-8416, the producer of yimeimycin, was isolated from a soil sample collected in Hangzhou, Zhejiang province, China. Based on the investigation of morphological, cultural, physiological and biochemical characteristic as well as the cell wall chemical composition, strain HA8416 is extremely similar to Streptomyces hygrospinosus SF-104, and named Streptomyces hygrospinosus var tianmushanensis n. var. Sand et al. By means of spectroscopic analysis (UV, 1 H-NMR, DEPT CNMR and H-H COSY), yimeimycin was identified as a new antibiotic of the nucleoside family. Yimeimeycin appeared no activities against G + /G-bacteria, but was active against the fungi, Sphaerotheca cucurbitae, Pellicularia sasakii, Colletotrichum orbiculare, especially

  17. Nuclear magnetic resonance spectroscopy in the structure elucidation and biosynthesis of natural products

    International Nuclear Information System (INIS)

    Meksuriyen, D.

    1988-01-01

    Examination of a chloroform extract of Dracaena loureiri Gagnep (Agavaceae), a Thia medicinal plant possessing antibacterial activity, has led to the isolation of fifteen flavenoids. The biogenic relationships among these flavenoids isolated were briefly discussed. Definition of the skeleton and the unambiguous assignment of all of the protons of the isolates was achieved through extensive 2D-homonuclear chemical shift correlation, nuclear Overhauser effect (NOE) difference spectroscopy and 2D-NOE experiments. The 1 H and 13 C NMR spectra of staurosporine, a potent biologically active agent from Streptomyces staurosporeus, were unambiguously assigned by using 2D homonuclear chemical shift correlation, NOE, 1 H-detected heteronuclear multiple-quantum coherence via direct coupling and via multiple-bond coupling for resonance assignments of protonated and nonprotonated carbons, respectively. S. Staurosporeus was found to utilize endogenous and exogenous D- and L-isomers of trytophan in the production of staurosporine. The biosynthesis of staurosporine was examined by employing carbon-14, tritium, and carbon-13 labeled precursors

  18. Structure elucidation of some insect pheromones : a contribution to the development of selective pest control agents

    NARCIS (Netherlands)

    Persoons, C.J.

    1977-01-01

    The use of pheromones is one of the methods currently being investigated intensively as an alternative method of insect control. The various ways in which pheromones might be used in insect control programmes are briefly discussed in Chapter 1.

    Chapter 2 gives a detailed description of the

  19. Synthesis and structural elucidation of glutathione and N-aceyl-cysteine conjugates of 5-aminosalicylic acid

    DEFF Research Database (Denmark)

    Jensen, J.; Cornett, Claus; Olsen, C. E.

    1993-01-01

    The ability of 5-aminosalicylic acid (5-ASA) to be oxidized to a quinone monoimine compound capable of conjugating with nucleophilic compounds such as N-acetyl-cysteine (NAC) and glutathione (GSH) has been investigated in vitro. Three isomeric conjugates of 5-ASA and NAC as well as three isomeric...... conjugates of 5-ASA and GSH were found to be formed. 5-ASA was initially oxidized by PbO2 in a solution of TRIS-HCl buffer pH 9.3 followed by the in situ addition of N-acetyl-cysteine or glutathione to the oxidized 5-ASA at pH 7.5. The resulting conjugates were N-acetylated at the aromatic amino group...... to investigate whether such conjugates are excreted in the urine from persons treated with 5-ASA. The N-acetyl-cysteine conjugates could be detected by fluorescense, which resulted in low detection limits ranging from 0.02 mug to 0.06 mug per ml corresponding to the transformation of about 0.003% of the daily...

  20. Proton NMR studies on Megaphaera elsdenii flavodoxin : structure elucidation by 2D-NMR and implications

    NARCIS (Netherlands)

    Mierlo, van C.

    1990-01-01

    1H NMR techniques have been applied for a thorough study of the uncrystallizable Megasphaera elsdenii flavodoxin in its three redox states. The aim of the research project described in this thesis was to obtain answers regarding questions

  1. Isolationand structure elucidation of coumarin and cinamate derivatives from Lycium ruthenicum

    Directory of Open Access Journals (Sweden)

    Hassan Valizadeh

    2014-10-01

    Full Text Available Lyciumspecies is a popular medicinal plant in the traditional Chinese medicine and Lycium ru-thenicum is a native medicinal plant of Iran. Lycium genus has several biologically important properties too. Investigation of chemical composition of ethyl acetate extract of this plant is the goal of this study. Two coumarins (Scopoletin and Sculetin and Methyl-2-hydroxy-4-undecanoxy-trans-cinamate were isolated and characterized as the major constituents using 1H NMR, 13C NMR and FT-IR spectroscopic data, MS spectrometry, elemental analysis and by comparison with the literature values. Phytochemical investigation of Lyciumruthenicum demonstrated the presence of important biologically active compounds. This is the first phyto-chemical study of this species in Iran.

  2. Structure elucidation and degradation kinetic study of Ofloxacin using surface enhanced Raman spectroscopy

    Science.gov (United States)

    El-Zahry, Marwa R.; Lendl, Bernhard

    2018-03-01

    A simple, fast and sensitive surface enhanced Raman spectroscopy (SERS) method for quantitative determination of fluoroquinolone antibiotic Ofloxacin (OFX) is presented. Also the stability behavior of OFX was investigated by monitoring the SERS spectra of OFX after various degradation processes. Acidic, basic and oxidative force degradation processes were applied at different time intervals. The forced degradation conditions were conducted and followed using SERS method utilizing silver nanoparticles (Ag NPs) as a SERS substrate. The Ag NPs colloids were prepared by reduction of silver nitrate using polyethyelene glycol (PEG) as a reducing and stabilizing agent. Validation tests were done in accordance with International Conference on Harmonization (ICH) guidelines. The calibration curve with a correlation coefficient (R = 0.9992) was constructed as a relationship between the concentration range of OFX (100-500 ng/ml) and SERS intensity at 1394 cm- 1 band. LOD and LOQ values were calculated and found to be 23.5 ng/ml and 72.6 ng/ml, respectively. The developed method was applied successfully for quantitation of OFX in different pharmaceutical dosage forms. Kinetic parameters were calculated including rate constant of the degradation of the studied antibiotic.

  3. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell.

    Science.gov (United States)

    Timmers, Ruud A; Rothballer, Michael; Strik, David P B T B; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

    2012-04-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors.

  4. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Timmers, Ruud A.; Strik, David P.B.T.B.; Hamelers, Bert; Buisman, Cees [Wageningen Univ. (Netherlands). Sub-dept. of Environmental Technology; Rothballer, Michael; Hartmann, Anton [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg (Germany). Dept. Microbe-Plant Interactions; Engel, Marion; Schulz, Stephan; Schloter, Michael [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg (Germany). Dept. Terrestrial Ecogenetics

    2012-04-15

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors. (orig.)

  5. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    NARCIS (Netherlands)

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

  6. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    OpenAIRE

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

  7. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    OpenAIRE

    Timmers, Ruud A.; Rothballer, Michael; Strik, David P. B. T. B.; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

  8. Computer-aided structure elucidation Pt. 2. /sup 1/H-NMR data interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Szalontai, G; Recsey, Zs; Csapo, Z [Nehezvegyipari Kutato Intezet, Veszprem (Hungary)

    1982-01-01

    A computerized /sup 1/H-NMR data interpretation system has been developed using the artificial intelligence approach. An attempt has been made to overcome the difficulties of interpreting higher order spin systems. Proton-containing functional groups are divided into subgroups according to their spectroscopic behaviour and the information they bear. Spin simulation is used to study the effect of substituents on the higher order splitting patterns. Illustrative examples are given.

  9. Computer-aided structure elucidation Pt. 3. Extended version of assigner system

    Energy Technology Data Exchange (ETDEWEB)

    Szalontai, G; Csapo, Z; Recsey, Zs [Nehezvegyipari Kutato Intezet, Veszprem (Hungary)

    1982-01-01

    Computer-aided interpretation of /sup 13/C-NMR, /sup 1/H-NMR and IR spectra of organic molecules (M.W.<=500) has been performed by an artificial intelligence approach. A procedure for the joint /sup 13/C-NMR - /sup 1/H-NMR - IR spectrum interpretation is outlined. Possible ways of finding acceptable greater fragments on the basis of /sup 1/H-NMR - /sup 13/C-NMR data and of /sup 13/C-NMR data alone are also described. Detailed examples are given to demonstrate the capability of the system.

  10. NMR-Assisted Structure Elucidation of an Anticancer Steroid-β-Enaminone Derivative

    Directory of Open Access Journals (Sweden)

    Donald Poirier

    2017-11-01

    Full Text Available The fortuitous modification of a quinoline-proline-piperazine side chain linked to a steroid in the presence of lithium (trimethylsilyl acetylide has generated an unknown product that is more active than its precursor. After having characterized two β-enaminones (two-carbon homologation compounds that were generated from a simplified model side chain, we have identified the unknown product as being the β-enaminone steroid derivative 1. NMR analysis, especially two-dimensional (2D experiments (correlation spectroscopy (COSY, NOE spectroscopy (NOESY, heteronuclear single-quantum correlation (HSQC and heteronuclear multiple-bond correlation (HMBC provided crucial information that was found essential in the characterization of enaminone 1. We also proposed a mechanism to rationalize the formation of this biologically active compound.

  11. Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rajput, Nav Nidhi; Murugesan, Vijayakumar; Shin, Yongwoo; Han, Kee Sung; Lau, Kah Chun; Chen, Junzheng; Liu, Jun; Curtiss, Larry A.; Mueller, Karl T.; Persson, Kristin A.

    2017-04-10

    Designing optimal electrolytes is key to enhancing the performance of energy storage devices,especially relating to cycle life, efficiency, and stability.1 Specifically, for future beyond-Li ion energy storage, there is still ample room for electrolyte improvements. Among the candidates for higher gravimetric energy storage, the Li-S battery is considered quite promising, owing to its theoretical specific energy density (2600 Wh/kg) and specific capacity (1675 mAh/g) and significantly lower cost as compared to state-of-art lithium-ion batteries.

  12. Stable expression of human thyrotropin (hTSH) in mammalian cells (CHO) expressing α2,6 sialyltransferase

    International Nuclear Information System (INIS)

    Damiani, Renata

    2009-01-01

    A CHO cell line, previously genetically modified by the introduction of rat α2,6-sialyltransferase cDNA, generated for the first time a human-like sialylated recombinant hTSH (hlsr-hTSH) more similar to the native hormone, with 61% of α2,3- and 39% of α2,6-linked sialic acid residues. The best clone, when submitted to gene amplification with up to 8 μM methotrexate, presented a secretion level of ∼2 μg hTSH/10 6 cells/day, useful for product purification and characterization. The relative molecular masses (M r ) of the heterodimer and of the α- and β-subunits of purified hlsr-hTSH, determined by MALDI-TOF mass spectrometry, and the relative hydrophobicities, determined by RP-HPLC, were not remarkably different from those presented by two r-hTSH preparations secreted by normal CHO cells. Some differences were observed, though, in N-glycan composition, with more tri- and much more tetra-sialylated structures in hlsr-hTSH. When analyzed via an in vivo bioassay based on hTSH-induced T 4 release in mice, hlsr-hTSH was shown to be equipotent (p > 0.05) with the commercial preparation of r-hTSH (Thyrogen), and 1.5-fold more potent than native hTSH (p < 0.001). (author)

  13. Elucidating Small-Scale Animal-Fluid Interactions in the Deep Sea

    Science.gov (United States)

    Katija, K.; Sherman, A.; Graves, D.; Kecy, C. D.; Klimov, D.; Robison, B. H.

    2016-02-01

    The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet remains one of the least explored. Little-known marine organisms that inhabit midwater have developed life strategies that contribute to their evolutionary success, and understanding interactions with their physical, fluid environment will shed light on these strategies. Although significant advances in underwater vehicle technologies have improved access to midwater, small-scale, in situ fluid mechanics measurement methods that seek to quantify the interactions that midwater organisms have with their physical environment are lacking. Here we present DeepPIV, an instrumentation package affixed to remotely operated vehicles that quantifies fluid motions from the surface of the ocean down to 4000 m depths. Utilizing ambient suspended particulate, fluid-structure interactions can be evaluated on a range of marine organisms in midwater and on the benthos. As a proof of concept for DeepPIV, we targeted giant larvaceans (Bathochordaeus stygias) in Monterey Bay that create mucus houses to filter food. Once mucus houses become clogged, they are abandoned by the larvacean, and are left to sink to the ocean bottom; in Monterey Bay, sinking mucus houses contribute to nearly a third of the particulate on the ocean bottom. Little is known about the structure of these mucus houses and the function they play in selectively filtering particles. Using DeepPIV, we reveal the complex structures and flows generated within larvacean mucus houses, which are used to ultimately elucidate how these structures function.

  14. Elucidation of amyloid beta-protein oligomerization mechanisms: discrete molecular dynamics study.

    Science.gov (United States)

    Urbanc, B; Betnel, M; Cruz, L; Bitan, G; Teplow, D B

    2010-03-31

    Oligomers of amyloid beta-protein (Abeta) play a central role in the pathology of Alzheimer's disease. Of the two predominant Abeta alloforms, Abeta(1-40) and Abeta(1-42), Abeta(1-42) is more strongly implicated in the disease. We elucidated the structural characteristics of oligomers of Abeta(1-40) and Abeta(1-42) and their Arctic mutants, [E22G]Abeta(1-40) and [E22G]Abeta(1-42). We simulated oligomer formation using discrete molecular dynamics (DMD) with a four-bead protein model, backbone hydrogen bonding, and residue-specific interactions due to effective hydropathy and charge. For all four peptides under study, we derived the characteristic oligomer size distributions that were in agreement with prior experimental findings. Unlike Abeta(1-40), Abeta(1-42) had a high propensity to form paranuclei (pentameric or hexameric) structures that could self-associate into higher-order oligomers. Neither of the Arctic mutants formed higher-order oligomers, but [E22G]Abeta(1-40) formed paranuclei with a similar propensity to that of Abeta(1-42). Whereas the best agreement with the experimental data was obtained when the charged residues were modeled as solely hydrophilic, further assembly from spherical oligomers into elongated protofibrils was induced by nonzero electrostatic interactions among the charged residues. Structural analysis revealed that the C-terminal region played a dominant role in Abeta(1-42) oligomer formation whereas Abeta(1-40) oligomerization was primarily driven by intermolecular interactions among the central hydrophobic regions. The N-terminal region A2-F4 played a prominent role in Abeta(1-40) oligomerization but did not contribute to the oligomerization of Abeta(1-42) or the Arctic mutants. The oligomer structure of both Arctic peptides resembled Abeta(1-42) more than Abeta(1-40), consistent with their potentially more toxic nature.

  15. Use of isotope effects to elucidate enzyme mechanisms

    International Nuclear Information System (INIS)

    Cleland, W.W.

    1982-01-01

    The chemical bond breaking steps are normally not rate limiting for enzymatic reactions. However, comparison of deuterium and tritium isotope effects on the same reaction, especially when coupled with 13 C isotope effects for the same step measured with deuterated as well as unlabeled substrates, allows calculation of the intrinsic isotope effects on the bond breaking steps and thus a determination of the commitments to catalysis for the reactants. The variation in observed isotope effects as a function of reactant concentration can be used to determine kinetic mechanisms, while the pH variation of isotope effects can determine the stickiness of the reactants and which portions of the reactant mechanism are pH dependent. Finally the size of primary and secondary intrinsic isotope effects can be used to determine transition state structure

  16. Structuralism.

    Science.gov (United States)

    Piaget, Jean

    Provided is an overview of the analytical method known as structuralism. The first chapter discusses the three key components of the concept of a structure: the view of a system as a whole instead of so many parts; the study of the transformations in the system; and the fact that these transformations never lead beyond the system but always…

  17. Elucidating the Interdependence of Drug Resistance from Combinations of Mutations.

    Science.gov (United States)

    Ragland, Debra A; Whitfield, Troy W; Lee, Sook-Kyung; Swanstrom, Ronald; Zeldovich, Konstantin B; Kurt-Yilmaz, Nese; Schiffer, Celia A

    2017-11-14

    HIV-1 protease is responsible for the cleavage of 12 nonhomologous sites within the Gag and Gag-Pro-Pol polyproteins in the viral genome. Under the selective pressure of protease inhibition, the virus evolves mutations within (primary) and outside of (secondary) the active site, allowing the protease to process substrates while simultaneously countering inhibition. The primary protease mutations impede inhibitor binding directly, while the secondary mutations are considered accessory mutations that compensate for a loss in fitness. However, the role of secondary mutations in conferring drug resistance remains a largely unresolved topic. We have shown previously that mutations distal to the active site are able to perturb binding of darunavir (DRV) via the protein's internal hydrogen-bonding network. In this study, we show that mutations distal to the active site, regardless of context, can play an interdependent role in drug resistance. Applying eigenvalue decomposition to collections of hydrogen bonding and van der Waals interactions from a series of molecular dynamics simulations of 15 diverse HIV-1 protease variants, we identify sites in the protease where amino acid substitutions lead to perturbations in nonbonded interactions with DRV and/or the hydrogen-bonding network of the protease itself. While primary mutations are known to drive resistance in HIV-1 protease, these findings delineate the significant contributions of accessory mutations to resistance. Identifying the variable positions in the protease that have the greatest impact on drug resistance may aid in future structure-based design of inhibitors.

  18. SUCROSE SYNTHASE: ELUCIDATION OF COMPLEX POST-TRANSLATIONAL REGULATORY MECHANISMS

    Energy Technology Data Exchange (ETDEWEB)

    Steven C. Huber

    2009-05-12

    Studies have focused on the enzyme sucrose synthase, which plays an important role in the metabolism of sucrose in seeds and tubers. There are three isoforms of SUS in maize, referred to as SUS1, SUS-SH1, and SUS2. SUS is generally considered to be tetrameric protein but recent evidence suggests that SUS can also occur as a dimeric protein. The formation of tetrameric SUS is regulated by sucrose concentration in vitro and this could also be an important factor in the cellular localization of the protein. We found that high sucrose concentrations, which promote tetramer formation, also inhibit the binding of SUS1 to actin filaments in vitro. Previously, high sucrose concentrations were shown to promote SUS association with the plasma membrane. The specific regions of the SUS molecule involved in oligomerization are not known, but we identified a region of the SUS1 moelcule by bioinformatic analysis that was predicted to form a coiled coil. We demonstrated that this sequence could, in fact, self-associate as predicted for a coiled coil, but truncation analysis with the full-length recombinant protein suggested that it was not responsible for formation of dimers or tetramers. However, the coiled coil may function in binding of other proteins to SUS1. Overall, sugar availability may differentially influence the binding of SUS to cellular structures, and these effects may be mediated by changes in the oligomeric nature of the enzyme.

  19. Combining pharmacophore fingerprints and PLS-discriminant analysis for virtual screening and SAR elucidation

    DEFF Research Database (Denmark)

    Askjær, Sune; Langgård, Morten

    2008-01-01

    The criterion of success for the initial stages of a ligand-based drug-discovery project is dual. First, a set of suitable lead compounds has to be identified. Second, a level of a preliminary structure-activity relationship (SAR) of the identified ligands has to be established in order to guide ...... by the protein-binding site known from X-ray complexes. The result of this analysis assists in explaining the efficiency of 2D pharmacophore fingerprints as descriptors in virtual screening....... the lead optimization toward a final drug candidate. This paper presents a combined approach to solving these two problems of ligand-based virtual screening and elucidation of SAR based on interplay between pharmacophore fingerprints and interpretation of PLS-discriminant analysis (PLS-DA) models....... The virtual screening capability of the PLS-DA method is compared to group fusion maximum similarity searching in a test using four graph-based pharmacophore fingerprints over a range of 10 diverse targets. The PLS-DA method was generally found to do better than the Smax method. The GpiDAPH3 and PCH...

  20. Crosslinked electrospun PVA nanofibrous membranes: elucidation of their physicochemical, physicomechanical and molecular disposition

    International Nuclear Information System (INIS)

    Shaikh, Rubina P; Kumar, Pradeep; Choonara, Yahya E; Du Toit, Lisa C; Pillay, Viness

    2012-01-01

    The effects of modifying electrospun poly(vinyl alcohol) (PVA) nanofibers through crosslinking using glutaraldehyde (GA) are explored in this paper. Various concentrations of PVA solutions containing model drugs rifampicin (RIF) and isoniazid (INH) were electrospun and thereafter crosslinked using GA vapors. PVA nanofibers demonstrated high drug entrapment efficiency of 98.77% ± 1.384% and 95.07% ± 1.988% for the INH- and RIF-loaded PVA nanofibers, respectively. The surface morphology, molecular vibrational transitions, tensile attributes and in vitro drug release were characterized and supported by in silico molecular mechanics simulations. Results indicated that crosslinking caused a significant reduction in the rate of drug release where 81.11% ± 2.35% of INH and 59.31% ± 2.57% of RIF were released after 12 h. Tensile properties such as the ultimate strength and Young's modulus increased after crosslinking, caused by crosslinks forming between PVA nanofibers as was revealed through scanning electron microscopy analysis. Fourier Transform infrared analysis was conducted to further support the mode of crosslinking. Additionally, image processing analysis was carried out to quantify the effect of formulation variables on the morphology of nanofibers. Furthermore, the effect of GA-induced crosslinking and addition of drugs on the performance of electrospun fibers was further elucidated and conceptualized using a molecular mechanics assisted model building and energy refinement approach via molecular mechanics energy relationships by exploring the spatial disposition of energy-minimized molecular structures of the polymer, crosslinker and the drugs. (paper)

  1. Elucidation of self-induced sloshing occurrence mechanism using numerical analysis

    International Nuclear Information System (INIS)

    Saeki, Soichi; Madarame, Haruki; Okamoto, Koji; Tanaka, Nobukazu.

    1995-01-01

    In liquid metal-cooled fast breeder reactors, there is free liquid surface in a reactor vessel and others, and by reducing the size of the reactor vessel and others, it is necessary to increase the flow velocity of liquid sodium coolant. In the free liquid surface in which fast circulating flow exists, undesirable phenomena like waving and bubble catching are feared. The self-induced sloshing taken up in this study is one of these phenomena. Since the actual machine has complex three-dimensional structure, in order to forecast the occurrence of sloshing, it is necessary to elucidate the mechanism of vibration occurrence. The mechanism of occurrence of self-induced sloshing due to horizontal and vertical plane jets has been explained a number of times so far. In this study, by applying the model of the occurrence mechanism of Fukaya to horizontal plane jet, the self-induced sloshing due to horizontal plane jet was simulated by numerical analysis. Based on the results, it was attempted to examine the vibration energy supplied to sloshing in a whole flow field and the dependence of sloshing region on water depth and flow velocity. The numerical simulation, the analysis of the occurrence mechanism by using the numerical analysis code and the results are reported. (K.I.)

  2. Convergent preparation and photophysical characterization of dimaleimide dansyl fluorogens: elucidation of the maleimide fluorescence quenching mechanism.

    Science.gov (United States)

    Guy, Julia; Caron, Karine; Dufresne, Stéphane; Michnick, Stephen W; Skene, W G; Keillor, Jeffrey W

    2007-10-03

    Dimaleimide fluorogens are being developed for application to fluorescent protein labeling. In this method, fluorophores bearing two maleimide quenching groups do not fluoresce until both maleimide groups have undergone thiol addition reactions with the Cys residues of the target protein sequence [J. Am. Chem. Soc. 2005, 127, 559-566]. In this work, a new convergent synthetic route was developed that would allow any fluorophore to be attached via a linker to a dimaleimide moiety in a modular fashion. Series of dimaleimide and dansyl derivatives were thus prepared conveniently and used to elucidate the mechanism of maleimide quenching. Intersystem crossing was ruled out as a potential quenching pathway, based on the absence of a detectable triplet intermediate by laser flash photolysis. Stern-Volmer rate constants were measured with exogenous dimaleimide quenchers and found to be close to the diffusion-controlled limits, consistent with electron transfer being thermodynamically favorable. The thermodynamic feasibility of the photoinduced electron transfer (PET) quenching mechanism was verified by cyclic voltammetry. The redox potentials measured for dansyl and maleimide confirm that electron transfer from the dansyl excited state to a pendant maleimide group is exergonic and is responsible for fluorescence quenching of the fluorogens studied herein. Taking this PET quenching mechanism into account, future fluorogenic protein labeling agents will be designed with spacers of variable length and rigidity to probe the structure-property PET efficiency relationship.

  3. Elucidation of the relationships between H-bonding patterns and excited state dynamics in cyclovalone.

    Science.gov (United States)

    Lamperti, Marco; Maspero, Angelo; Tønnesen, Hanne H; Bondani, Maria; Nardo, Luca

    2014-08-28

    Cyclovalone is a synthetic curcumin derivative in which the keto-enolic system is replaced by a cyclohexanone ring. This modification of the chemical structure might in principle result in an excited state that is more stable than that of curcumin, which in turn should produce an enhanced phototoxicity. Indeed, although curcumin exhibits photosensitized antibacterial activity, this compound is characterized by very fast excited-state dynamics which limit its efficacy as a photosensitizer. In previous works we showed that the main non-radiative decay pathway of keto-enolic curcuminoids is through excited-state transfer of the enolic proton to the keto-oxygen. Another effective deactivation pathway involves an intermolecular charge transfer mechanism occurring at the phenyl rings, made possible by intramolecular H-bonding between the methoxy and the hydroxyl substituent. In this paper we present UV-Vis and IR absorption spectra data with the aim of elucidating the intramolecular charge distribution of this compound and its solvation patterns in different environments, with particular focus on solute-solvent H-bonding features. Moreover, we discuss steady state and time-resolved fluorescence data that aim at characterizing the excited-state dynamics of cyclovalone, and we compare its decay photophysics to that of curcumin. Finally, because during the characterization procedures we found evidence of very fast photodegradation of cyclovalone, its photostability in four organic solvents was studied by HPLC and the corresponding relative degradation rates were calculated.

  4. Elucidation of the Relationships between H-Bonding Patterns and Excited State Dynamics in Cyclovalone

    Directory of Open Access Journals (Sweden)

    Marco Lamperti

    2014-08-01

    Full Text Available Cyclovalone is a synthetic curcumin derivative in which the keto-enolic system is replaced by a cyclohexanone ring. This modification of the chemical structure might in principle result in an excited state that is more stable than that of curcumin, which in turn should produce an enhanced phototoxicity. Indeed, although curcumin exhibits photosensitized antibacterial activity, this compound is characterized by very fast excited-state dynamics which limit its efficacy as a photosensitizer. In previous works we showed that the main non-radiative decay pathway of keto-enolic curcuminoids is through excited-state transfer of the enolic proton to the keto-oxygen. Another effective deactivation pathway involves an intermolecular charge transfer mechanism occurring at the phenyl rings, made possible by intramolecular H-bonding between the methoxy and the hydroxyl substituent. In this paper we present UV-Vis and IR absorption spectra data with the aim of elucidating the intramolecular charge distribution of this compound and its solvation patterns in different environments, with particular focus on solute-solvent H-bonding features. Moreover, we discuss steady state and time-resolved fluorescence data that aim at characterizing the excited-state dynamics of cyclovalone, and we compare its decay photophysics to that of curcumin. Finally, because during the characterization procedures we found evidence of very fast photodegradation of cyclovalone, its photostability in four organic solvents was studied by HPLC and the corresponding relative degradation rates were calculated.

  5. Symmetry Breaking in NMR Spectroscopy: The Elucidation of Hidden Molecular Rearrangement Processes

    Directory of Open Access Journals (Sweden)

    Michael J. McGlinchey

    2014-08-01

    Full Text Available Variable-temperature NMR spectroscopy is probably the most convenient and sensitive technique to monitor changes in molecular structure in solution. Rearrangements that are rapid on the NMR time-scale exhibit simplified spectra, whereby non-equivalent nuclear environments yield time-averaged resonances. At lower temperatures, when the rate of exchange is sufficiently reduced, these degeneracies are split and the underlying “static” molecular symmetry, as seen by X-ray crystallography, becomes apparent. Frequently, however, such rearrangement processes are hidden, even when they become slow on the NMR time-scale, because the molecular point group remains unchanged. Judicious symmetry breaking, such as by substitution of a molecular fragment by a similar, but not identical moiety, or by the incorporation of potentially diastereotopic (chemically non-equivalent nuclei, allows the elucidation of the kinetics and energetics of such processes. Examples are chosen that include a wide range of rotations, migrations and other rearrangements in organic, inorganic and organometallic chemistry.

  6. Elucidation of the glucose transport pathway in glucose transporter 4 via steered molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Aswathy Sheena

    Full Text Available BACKGROUND: GLUT4 is a predominant insulin regulated glucose transporter expressed in major glucose disposal tissues such as adipocytes and muscles. Under the unstimulated state, GLUT4 resides within intracellular vesicles. Various stimuli such as insulin translocate this protein to the plasma membrane for glucose transport. In the absence of a crystal structure for GLUT4, very little is known about the mechanism of glucose transport by this protein. Earlier we proposed a homology model for GLUT4 and performed a conventional molecular dynamics study revealing the conformational rearrangements during glucose and ATP binding. However, this study could not explain the transport of glucose through the permeation tunnel. METHODOLOGY/PRINCIPAL FINDINGS: To elucidate the molecular mechanism of glucose transport and its energetic, a steered molecular dynamics study (SMD was used. Glucose was pulled from the extracellular end of GLUT4 to the cytoplasm along the pathway using constant velocity pulling method. We identified several key residues within the tunnel that interact directly with either the backbone ring or the hydroxyl groups of glucose. A rotation of glucose molecule was seen near the sugar binding site facilitating the sugar recognition process at the QLS binding site. CONCLUSIONS/SIGNIFICANCE: This study proposes a possible glucose transport pathway and aids the identification of several residues that make direct interactions with glucose during glucose transport. Mutational studies are required to further validate the observation made in this study.

  7. Using Genetic Buffering Relationships Identified in Fission Yeast To Elucidate the Molecular Pathology of Tuberous Sclerosis

    Science.gov (United States)

    2016-07-01

    tsc1 and tsc2 loss of function mutations in Schizosaccharomyces pombe. Northeast Regional Yeast Meeting, June 16-17, University at Buffalo, The State...AWARD NUMBER: W81XWH-14-1-0169 TITLE: Using Genetic Buffering Relationships Identified in Fission Yeast To Elucidate the Molecular Pathology of...SUBTITLE Using Genetic Buffering Relationships Identified in Fission 5a. CONTRACT NUMBER W81XWH-14-1-0169 Yeast to Elucidate the Molecular Pathology

  8. Elucidating the Nature and Mechanism of Tic Improvement in Tourette Syndrome: A Pilot Study

    Directory of Open Access Journals (Sweden)

    David Shprecher

    2014-04-01

    Full Text Available Background: For unclear reasons, many Tourette syndrome (TS children report near‐complete tic remission by young adulthood. Immature maturation of brain networks, observed with resting‐state functional MRI (rs‐fc‐MRI in adolescents and adults with TS, might evolve to a mature pattern in adults who experience tic improvement or remission. We explored the feasibility of testing this hypothesis in our population of young adult TS males, each with prior clinical assessments completed during childhood as part of a separate TS Association Genetics Consortium study. Methods: A total of 10 TS males (off tic suppressing drugs for at least 6 months aged 19–32 years, mean follow‐up interval 7.5 (2 to 13 years, and 11 neurologically normal controls were enrolled and underwent 3‐Tesla structural and rs‐fc‐MRI sequences. Results: The mean change in Yale Global Tic Severity Scale (YGTSS was −31.5% (total and −26.6% (YGTSS motor+vocal. Two subjects reported resolution of tic‐related disability, with drops from mean 45 to 16.5 (YGTSS‐total and 25 to 11.5 (YGTSS motor+vocal.. Rs‐fc‐MRI revealed significantly increased connectivity between the ipsilateral anterior and mid cingulate cortex and striatum, increased connectivity between local connections, and decreased connectivity between more distant connections; representing an immature connectivity pattern.Discussion: Similar to previous reports, we found immature patterns of functional connectivity in adult TS subjects. Despite a lack of complete tic remission, two subjects exhibited dramatic drops in tic severity that correlated with tic‐related disability improvement. More work is needed to elucidate the mechanism of such dramatic improvement in TS.

  9. Elucidating the nature and mechanism of tic improvement in tourette syndrome: a pilot study.

    Science.gov (United States)

    Shprecher, David R; Gannon, Keenan; Agarwal, Nivedita; Shi, Xianfeng; Anderson, Jeffrey S

    2014-01-01

    For unclear reasons, many Tourette syndrome (TS) children report near-complete tic remission by young adulthood. Immature maturation of brain networks, observed with resting-state functional MRI (rs-fc-MRI) in adolescents and adults with TS, might evolve to a mature pattern in adults who experience tic improvement or remission. We explored the feasibility of testing this hypothesis in our population of young adult TS males, each with prior clinical assessments completed during childhood as part of a separate TS Association Genetics Consortium study. A total of 10 TS males (off tic suppressing drugs for at least 6 months) aged 19-32 years, mean follow-up interval 7.5 (2 to 13) years, and 11 neurologically normal controls were enrolled and underwent 3-Tesla structural and rs-fc-MRI sequences. The mean change in Yale Global Tic Severity Scale (YGTSS) was -31.5% (total) and -26.6% (YGTSS motor+vocal). Two subjects reported resolution of tic-related disability, with drops from mean 45 to 16.5 (YGTSS-total) and 25 to 11.5 (YGTSS motor+vocal.). Rs-fc-MRI revealed significantly increased connectivity between the ipsilateral anterior and mid cingulate cortex and striatum, increased connectivity between local connections, and decreased connectivity between more distant connections; representing an immature connectivity pattern. Similar to previous reports, we found immature patterns of functional connectivity in adult TS subjects. Despite a lack of complete tic remission, two subjects exhibited dramatic drops in tic severity that correlated with tic-related disability improvement. More work is needed to elucidate the mechanism of such dramatic improvement in TS.

  10. Essential elucidation for preparation of supported nickel phosphide upon nickel phosphate precursor

    International Nuclear Information System (INIS)

    Liu, Xuguang; Xu, Lei; Zhang, Baoquan

    2014-01-01

    Preparation of supported nickel phosphide (Ni 2 P) depends on nickel phosphate precursor, generally related to its chemical composition and supports. Study of this dependence is essential and meaningful for the preparation of supported Ni 2 P with excellent catalytic activity. The chemical nature of nickel phosphate precursor is revealed by Raman and UV–vis spectra. It is found that initial P/Ni mole ratio ≥0.8 prohibits the Ni-O-Ni bridge bonding (i.e., nickel oxide). This chemical bonding will not result in Ni 2 P structure, verified by XRD characterization results. The alumina (namely, γ-Al 2 O 3 , θ-Al 2 O 3 , or α-Al 2 O 3 ) with distinct physiochemical properties also results in diverse chemical nature of nickel phosphate, and then different nickel phosphides. The influence of alumina support on producing Ni 2 P was explained by the theory of surface energy heterogeneity, calculated by the NLDFT method based on N 2 -sorption isotherm. The uniform surface energy of α-Al 2 O 3 results only in the nickel phosphosate precursor and thus the Ni 2 P phase. - Graphical abstract: Surface energy heterogeneity in alumina (namely α-Al 2 O 3 , θ-Al 2 O 3 , and γ-Al 2 O 3 ) supported multi-oxidic precursors with different reducibilities and thus diverse nickel phosphides (i.e., Ni 3 P, Ni 12 P 5 , Ni 2 P). - Highlights: • Preparing pure Ni 2 P. • Elucidating nickel phosphate precursor. • Associating with surface energy

  11. Elucidation of the Synthetic Mechanism of Acylceramide, an Essential Lipid for Skin Barrier Function.

    Science.gov (United States)

    Ohno, Yusuke

    2017-01-01

    The primary function of the skin is to act as a permeability barrier that prevents water loss from inside the body and external invasion such as by pathogens, harmful substances, and allergens. Lipids play a critical role in skin barrier formation by forming multi-lamellar structures in the stratum corneum, the outermost cell layer of the epidermis. Ceramide, the backbone of sphingolipids, accounts for more than 50% of the stratum corneum lipids. Acylceramides are epidermis-specific ceramide species essential for skin barrier formation. Decreases in acylceramide levels and changes in ceramide composition and chain-length are associated with such cutaneous disorders as ichthyosis, atopic dermatitis, and psoriasis. Acylceramide consists of a long-chain base and an amide-linked ultra-long-chain fatty acid (ULCFA, 28-36 carbon chain), which is ω-hydroxylated and esterified with linoleic acid. Although the molecular mechanism by which acylceramide is generated has not been fully understood for decades, we recently identified two genes, CYP4F22 and PNPLA1, involved in acylceramide synthesis and elucidated the entire biosynthetic pathway of acylceramide: the synthesis of ULCFA by ELOVL1 and ELOVL4, ω-hydroxylation of the ULCFA by CYP4F22, amide-bond formation with a long-chain base by CERS3, and transacylation of linoleic acid from triacylglycerol to ω-hydroxyceramide by PNPLA1 to generate acylceramide. CYP4F22 and PNPLA1 are the causative genes of ichthyosis. We demonstrated that mutations of CYP4F22 or PNPLA1 markedly reduced acylceramide production. Our recent findings provide important insights into the molecular mechanisms of skin barrier formation and of ichthyosis pathogenesis.

  12. Plasma experiments elucidative for challenging problems investigated in other branches of science

    International Nuclear Information System (INIS)

    Sanduloviciu, M.; Popescu, S.

    2001-01-01

    Driving away from thermal equilibrium a plasma initially in an asymptotic stable state it is possible to identify the succession of the physical processes that form, as a whole, a new scenario of self-organization able to explain, besides the challenging problems of non-equilibrium physics, also some of the today not solved essential problems of the chemical and biological sciences. Thus, plasma experiments have revealed the presence of a local self-enhancement mechanism associated with long-range inhibition that explains pattern formation in general. Two successively produced instabilities originated in a positive feedback mechanism were identified to be at the origin of the spatial and spatial-temporal patterns, respectively. This feedback mechanism comprises a self-enhancing mechanism of the production of positive ions complemented by the creation of a net negative space charge by accumulation of electrons that have lost their kinetic energy in neutral excitations. The informational content concerning self-organization revealed by the plasma experiments suggests the presence of a new physical basis for the behavior of the systems working as differential negative resistance, but also new information on the actual cause of the anomalous transport of particles and energy. These results present special interest in solid state physics where the mechanism of current instabilities observed in semiconductors is today a non-conclusively solved problem. Anomalous transport of particles and energy is today a challenging problem of high energy physics because it is considered as the principal cause that impedes the improvement of the economical performances of fusion devices. Since all chemical and biological phenomena involve, at least, physical processes, the scenario of self-organization identified in plasma could be elucidative for understanding the phenomena, as for instance, the pattern formation in chemical media, but also the spontaneous self-assembling of the

  13. Elucidation of the fluctuation history of cosmic radiation and global environmental using AMS

    International Nuclear Information System (INIS)

    Horiuchi, Kazuho

    2008-01-01

    Recently, accuracy of AMS has further been raised in trace amounts of sample. Besides application of 14 C to the age estimation, it has been able to restore in detail the past fluctuation of cosmic radiation strength using the other radioactive isotopes ( 10 Be, 36 Cl etc) in environmental samples and to elucidate the correlation of this with the fluctuation of climate and environment. In this report, the attempts to elucidate the fluctuation history of cosmic radiation and global environment with ice cores using AMS are presented. (M.H.)

  14. Hypoxia and the Edema Syndrome: Elucidation of a Mechanism of Teratogenesis

    Science.gov (United States)

    The elucidation of mechanisms and pathogenesis of birth defects is exceedingly complex. Consequently, there are few examples where the etiology of birth defects caused by a specific agent has been well described. One such example is the "Edema Syndrome" first described by Casimer...

  15. Successful Use of [14C]Paracetamol Microdosing to Elucidate Developmental Changes in Drug Metabolism

    NARCIS (Netherlands)

    M.G. Mooij (Miriam); E. van Duijn (Esther); C.A.J. Knibbe (Catherijne); K.M. Allegaert (Karel); J. Windhorst (Judith); J.M. van Rosmalen (Joost); N.H. Hendrikse (N. Harry); D. Tibboel (Dick); W.H.J. Vaes (Wouter H. J.); S.N. de Wildt (Saskia)

    2017-01-01

    textabstractBackground: We previously showed the practical and ethical feasibility of using [14C]-microdosing for pharmacokinetic studies in children. We now aimed to show that this approach can be used to elucidate developmental changes in drug metabolism, more specifically, glucuronidation and

  16. Successful Use of [(14)C]Paracetamol Microdosing to Elucidate Developmental Changes in Drug Metabolism

    NARCIS (Netherlands)

    Mooij, M.G.; Duijn, E. van; Knibbe, C.A.; Allegaert, K.; Windhorst, A.D.; Rosmalen, J. van; Hendrikse, N.H.; Tibboel, D.; Vaes, W.H.; Wildt, S.N. de

    2017-01-01

    BACKGROUND: We previously showed the practical and ethical feasibility of using [(14)C]-microdosing for pharmacokinetic studies in children. We now aimed to show that this approach can be used to elucidate developmental changes in drug metabolism, more specifically, glucuronidation and sulfation,

  17. Dimensions of normal and abnormal personality: Elucidating DSM-IV personality disorder symptoms in adolescents

    NARCIS (Netherlands)

    Tromp, N.B.; Koot, H.M.

    2010-01-01

    The present study aimed to elucidate dimensions of normal and abnormal personality underlying DSM-IV personality disorder (PD) symptoms in 168 adolescents referred to mental health services. Dimensions derived from the Big Five of normal personality and from Livesley's (2006) conceptualization of

  18. Subclinical hypothyroidism diagnosed by thyrotropin-releasing hormone stimulation test in infertile women with basal thyroid-stimulating hormone levels of 2.5 to 5.0 mIU/L.

    Science.gov (United States)

    Lee, You-Jeong; Kim, Chung-Hoon; Kwack, Jae-Young; Ahn, Jun-Woo; Kim, Sung-Hoon; Chae, Hee-Dong; Kang, Byung-Moon

    2014-11-01

    To investigate the prevalence of subclinical hypothyroidism (SH) diagnosed by thyrotropin-releasing hormone (TRH) stimulating test in infertile women with basal thyroid-stimulating hormone (TSH) levels of 2.5 to 5.0 mIU/L. This study was performed in 39 infertile women with ovulatory disorders (group 1) and 27 infertile women with male infertility only (group 2, controls) who had basal serum TSH levels of 2.5 to 5.0 mIU/L and a TRH stimulating test. Serum TSH levels were measured before TRH injection (TSH0) and also measured at 20 minutes (TSH1) and 40 minutes (TSH2) following intravenous injection of 400 µg TRH. Exaggerated TSH response above 30 mIU/L following TRH injection was diagnosed as SH. Group 1 was composed of poor responders (subgroup A), patients with polycystic ovary syndrome (subgroup B) and patients with WHO group II anovulation except poor responder or polycystic ovary syndrome (subgroup C). The prevalence of SH was significantly higher in group 1 of 46.2% (18/39) compared with 7.4% (2/27) in group 2 (P=0.001). TSH0, TSH1, and TSH2 levels were significantly higher in group 1 than the corresponding values in group 2 (Pstimulation test had better be performed in infertile women with ovulatory disorders who have TSH levels between 2.5 and 5.0 mIU/L for early detection and appropriate treatment of SH.

  19. Phytochemical study of Helichrysum italicum (Roth) G. Don: Spectroscopic elucidation of unusual amino-phlorogucinols and antimicrobial assessment of secondary metabolites from medium-polar extract.

    Science.gov (United States)

    D'Abrosca, Brigida; Buommino, Elisabetta; Caputo, Pina; Scognamiglio, Monica; Chambery, Angela; Donnarumma, Giovanna; Fiorentino, Antonio

    2016-12-01

    Three unusual amino-phloroglucinols, named helichrytalicines A-C, along with seventeen known compounds including acetophenones, tremetrone derivatives, low-molecular weight phenols, flavonol glucosides, have been isolated from the medium-polar extract of Helichrysum italicum (Roth) G. Don, a medicinal plant typical of the Mediterranean vegetation. The structures of the compounds have been elucidated based on extensive 2D-NMR spectroscopic analyses, including COSY, TOCSY, HSQC, CIGAR-HMBC, H2BC and HSQC-TOCSY, along with Q-TOF HRMS 2 analysis. Stereostructure of the new compounds has been elucidated by Mosher's method and NOESY experiment. Antimicrobial properties against Staphylococcus epidermidis of selected compounds have been evaluated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. An analytical approach to elucidate the mechanism of grain refinement in calcium added Mg-Al alloys

    International Nuclear Information System (INIS)

    Nagasivamuni, B.; Ravi, K.R.

    2015-01-01

    Highlights: • Minor additions of Ca (<0.2%) refines the grain structure in Mg-(3, 6 and 9)Al alloys. • Analytical model elucidate that nucleation potency is enhanced after Ca addition. • Ternary Mg-Al-xCa growth restriction values (Q t ) are computed using Scheil equations. • Grain size predictions elucidate that nucleation events dominate grain refinement. • Growth restriction due to the higher Ca addition on grain refinement is not significant. - Abstract: The present study investigates the grain refinement of Mg-3Al, Mg-6Al and Mg-9Al alloys by calcium addition. The maximum reduction in grain size has been observed at 0.2% Ca addition in Mg-Al alloys, in which any further addition (up to 0.4%) has marginal improvement in grain refinement. The mechanism associated with the grain refinement of Mg-Al alloys by Ca addition is discussed in terms of growth restriction factor (Q) and constitutional undercooling (ΔT CS ) using analytical model. The influence of growth restriction factor (Q) on the final grain size of Ca-added Mg-Al alloys are calculated with the help analytical model by assuming that the number of nucleant particles is not altered through Ca addition. For accurate grain size calculations, the value of Q has been estimated with reliable thermodynamic database using Scheil solidification simulation. The comparison of predicted and experimental grain size results indicate that constitutional undercooling activation of nucleation events plays dominant role in grain refinement in Mg-Al alloys by calcium addition, whereas the increase in growth restriction value has negligible effect

  1. Active Interaction Mapping as a tool to elucidate hierarchical functions of biological processes.

    Science.gov (United States)

    Farré, Jean-Claude; Kramer, Michael; Ideker, Trey; Subramani, Suresh

    2017-07-03

    Increasingly, various 'omics data are contributing significantly to our understanding of novel biological processes, but it has not been possible to iteratively elucidate hierarchical functions in complex phenomena. We describe a general systems biology approach called Active Interaction Mapping (AI-MAP), which elucidates the hierarchy of functions for any biological process. Existing and new 'omics data sets can be iteratively added to create and improve hierarchical models which enhance our understanding of particular biological processes. The best datatypes to further improve an AI-MAP model are predicted computationally. We applied this approach to our understanding of general and selective autophagy, which are conserved in most eukaryotes, setting the stage for the broader application to other cellular processes of interest. In the particular application to autophagy-related processes, we uncovered and validated new autophagy and autophagy-related processes, expanded known autophagy processes with new components, integrated known non-autophagic processes with autophagy and predict other unexplored connections.

  2. Applying iPSCs for Preserving Endangered Species and Elucidating the Evolution of Mammalian Sex Determination.

    Science.gov (United States)

    Honda, Arata

    2018-04-06

    The endangered species Tokudaia osimensis has the unique chromosome constitution of 2n = 25, with an XO/XO sex chromosome configuration (2n = 25; XO). There is urgency to preserve this species and to elucidate the regulator(s) that can discriminate the males and females arising from the indistinguishable sex chromosome constitution. However, it is not realistic to examine this rare animal species by sacrificing individuals. Recently, true naïve induced pluripotent stem cells were successfully generated from a female T. osimensis, and the sexual plasticity of its germ cells was elucidated. This achievement constitutes the basis of an attractive research area, including embryonic fate determination, sex determination, and factor(s) that can replace the Y chromosome. In this essay, concrete strategies to conserve rare animal species and to reveal their specific characteristics using other compatible and abundant animals are proposed. © 2018 WILEY Periodicals, Inc.

  3. Epistemological controversies in the analytic field elucidated by the theological realm.

    Science.gov (United States)

    Squverer, Amos

    2015-08-01

    This article proposes to address certain epistemological controversies in psychoanalysis by elucidating them through the religious field. The theological field serves the author as the repressed, which indicates the latent stakes that continue to do work at the heart of these debates. The goal is to show how debates that take place on the epistemological level bring into confrontation different anthropological concepts and discursive traditions that have their roots in religious discourses. The principal hypothesis of the author is that the dissident theories of psychoanalysis can be understood as a return to a pre-monotheistic theological conception or to an idolatrous practice that aims, primarily, to undo castration. This hypothesis will be used to elucidate the debates with two authors: Adler and Rank. The author shows how these theorists, by leaving analytical ground, connect their theories to pre-monotheistic conceptions and highlight conceptual tools that are characteristic to them. Copyright © 2015 Institute of Psychoanalysis.

  4. Drug Elucidation: Invertebrate Genetics Sheds New Light on the Molecular Targets of CNS Drugs

    Directory of Open Access Journals (Sweden)

    Donard S. Dwyer

    2014-07-01

    Full Text Available Many important drugs approved to treat common human diseases were discovered by serendipity, without a firm understanding of their modes of action. As a result, the side effects and interactions of these medications are often unpredictable, and there is limited guidance for improving the design of next-generation drugs. Here, we review the innovative use of simple model organisms, especially Caenorhabditis elegans, to gain fresh insights into the complex biological effects of approved CNS medications. Whereas drug discovery involves the identification of new drug targets and lead compounds/biologics, and drug development spans preclinical testing to FDA approval, drug elucidation refers to the process of understanding the mechanisms of action of marketed drugs by studying their novel effects in model organisms. Drug elucidation studies have revealed new pathways affected by antipsychotic drugs, e.g., the insulin signaling pathway, a trace amine receptor and a nicotinic acetylcholine receptor. Similarly, novel targets of antidepressant drugs and lithium have been identified in C. elegans, including lipid-binding/transport proteins and the SGK-1 signaling pathway, respectively. Elucidation of the mode of action of anesthetic agents has shown that anesthesia can involve mitochondrial targets, leak currents and gap junctions. The general approach reviewed in this article has advanced our knowledge about important drugs for CNS disorders and can guide future drug discovery efforts.

  5. Toward a Method for Exposing and Elucidating Ethical Issues with Human Cognitive Enhancement Technologies.

    Science.gov (United States)

    Hofmann, Bjørn

    2017-04-01

    To develop a method for exposing and elucidating ethical issues with human cognitive enhancement (HCE). The intended use of the method is to support and facilitate open and transparent deliberation and decision making with respect to this emerging technology with great potential formative implications for individuals and society. Literature search to identify relevant approaches. Conventional content analysis of the identified papers and methods in order to assess their suitability for assessing HCE according to four selection criteria. Method development. Amendment after pilot testing on smart-glasses. Based on three existing approaches in health technology assessment a method for exposing and elucidating ethical issues in the assessment of HCE technologies was developed. Based on a pilot test for smart-glasses, the method was amended. The method consists of six steps and a guiding list of 43 questions. A method for exposing and elucidating ethical issues in the assessment of HCE was developed. The method provides the ground work for context specific ethical assessment and analysis. Widespread use, amendments, and further developments of the method are encouraged.

  6. The importance of the photosynthetic Gibbs effect in the elucidation of the Calvin-Benson-Bassham cycle.

    Science.gov (United States)

    Ebenhöh, Oliver; Spelberg, Stephanie

    2018-02-19

    The photosynthetic carbon reduction cycle, or Calvin-Benson-Bassham (CBB) cycle, is now contained in every standard biochemistry textbook. Although the cycle was already proposed in 1954, it is still the subject of intense research, and even the structure of the cycle, i.e. the exact series of reactions, is still under debate. The controversy about the cycle's structure was fuelled by the findings of Gibbs and Kandler in 1956 and 1957, when they observed that radioactive 14 CO 2 was dynamically incorporated in hexoses in a very atypical and asymmetrical way, a phenomenon later termed the 'photosynthetic Gibbs effect'. Now, it is widely accepted that the photosynthetic Gibbs effect is not in contradiction to the reaction scheme proposed by CBB, but the arguments given have been largely qualitative and hand-waving. To fully appreciate the controversy and to understand the difficulties in interpreting the Gibbs effect, it is illustrative to illuminate the history of the discovery of the CBB cycle. We here give an account of central scientific advances and discoveries, which were essential prerequisites for the elucidation of the cycle. Placing the historic discoveries in the context of the modern textbook pathway scheme illustrates the complexity of the cycle and demonstrates why especially dynamic labelling experiments are far from easy to interpret. We conclude by arguing that it requires sound theoretical approaches to resolve conflicting interpretations and to provide consistent quantitative explanations. © 2018 The Author(s).

  7. Elucidating the mechanisms of nickel compound uptake: A review of particulate and nano-nickel endocytosis and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Alexandra; Costa, Max, E-mail: Max.Costa@nyumc.org

    2012-04-01

    Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses — most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanism of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties.

  8. Elucidation of the conformational free energy landscape in H.pylori LuxS and its implications to catalysis

    Directory of Open Access Journals (Sweden)

    Bhattacharyya Moitrayee

    2010-08-01

    Full Text Available Abstract Background One of the major challenges in understanding enzyme catalysis is to identify the different conformations and their populations at detailed molecular level in response to ligand binding/environment. A detail description of the ligand induced conformational changes provides meaningful insights into the mechanism of action of enzymes and thus its function. Results In this study, we have explored the ligand induced conformational changes in H.pylori LuxS and the associated mechanistic features. LuxS, a dimeric protein, produces the precursor (4,5-dihydroxy-2,3-pentanedione for autoinducer-2 production which is a signalling molecule for bacterial quorum sensing. We have performed molecular dynamics simulations on H.pylori LuxS in its various ligand bound forms and analyzed the simulation trajectories using various techniques including the structure network analysis, free energy evaluation and water dynamics at the active site. The results bring out the mechanistic details such as co-operativity and asymmetry between the two subunits, subtle changes in the conformation as a response to the binding of active and inactive forms of ligands and the population distribution of different conformations in equilibrium. These investigations have enabled us to probe the free energy landscape and identify the corresponding conformations in terms of network parameters. In addition, we have also elucidated the variations in the dynamics of water co-ordination to the Zn2+ ion in LuxS and its relation to the rigidity at the active sites. Conclusions In this article, we provide details of a novel method for the identification of conformational changes in the different ligand bound states of the protein, evaluation of ligand-induced free energy changes and the biological relevance of our results in the context of LuxS structure-function. The methodology outlined here is highly generalized to illuminate the linkage between structure and function in

  9. Lack of association between autonomously functioning thyroid nodules and germline polymorphisms of the thyrotropin receptor and Gαs genes in a mild to moderate iodine-deficient Caucasian population.

    Science.gov (United States)

    Vicchio, Teresa Manuela; Giovinazzo, Salvatore; Certo, Rosaria; Cucinotta, Mariapaola; Micali, Carmelo; Baldari, Sergio; Benvenga, Salvatore; Trimarchi, Francesco; Campennì, Alfredo; Ruggeri, Rosaria Maddalena

    2014-07-01

    Mutations of the thyrotropin receptor (TSHR) and/or Gαs gene have been found in a number of, but not all, autonomously functioning thyroid nodules (AFTNs). Recently, in a 15-year-old girl with a hyperfunctioning papillary thyroid carcinoma, we found two somatic and germline single nucleotide polymorphisms (SNPs): a SNP of the TSHR gene (exon 7, codon 187) and a SNP of Gαs gene (exon 8, codon 185). The same silent SNP of the TSHR gene had been reported in patients with AFTN or familial non-autoimmune hyperthyroidism. No further data about the prevalence of the two SNPs in AFTNs as well as in the general population are available in the literature. To clarify the possible role of these SNPs in predisposing to AFTN. Germline DNA was extracted from blood leukocytes of 115 patients with AFTNs (43 males and 72 females, aged 31-85 years, mean ± SD = 64 ± 13) and 100 sex-matched healthy individuals from the same geographic area, which is marginally iodine deficient. The genotype distribution of the two SNPs was investigated by restriction fragment length polymorphism-polymerase chain reaction. The prevalence of the two SNPs in our study population was low and not different to that found in healthy individuals: 8 % of patients vs. 9 % of controls were heterozygous for the TSHR SNP and 4 % patients vs. 6 % controls were heterozygous for the Gαs SNP. One patient harbored both SNPs. These results suggest that these two SNPs do not confer susceptibility for the development of AFTN.

  10. Elucidating determinants of aerosol composition through particle-type-based receptor modeling

    Science.gov (United States)

    McGuire, M. L.; Jeong, C.-H.; Slowik, J. G.; Chang, R. Y.-W.; Corbin, J. C.; Lu, G.; Mihele, C.; Rehbein, P. J. G.; Sills, D. M. L.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

    2011-08-01

    An aerosol time-of-flight mass spectrometer (ATOFMS) was deployed at a semi-rural site in southern Ontario to characterize the size and chemical composition of individual particles. Particle-type-based receptor modelling of these data was used to investigate the determinants of aerosol chemical composition in this region. Individual particles were classified into particle-types and positive matrix factorization (PMF) was applied to their temporal trends to separate and cross-apportion particle-types to factors. The extent of chemical processing for each factor was assessed by evaluating the internal and external mixing state of the characteristic particle-types. The nine factors identified helped to elucidate the coupled interactions of these determinants. Nitrate-laden dust was found to be the dominant type of locally emitted particles measured by ATOFMS. Several factors associated with aerosol transported to the site from intermediate local-to-regional distances were identified: the Organic factor was associated with a combustion source to the north-west; the ECOC Day factor was characterized by nearby local-to-regional carbonaceous emissions transported from the south-west during the daytime; and the Fireworks factor consisted of pyrotechnic particles from the Detroit region following holiday fireworks displays. Regional aerosol from farther emissions sources was reflected through three factors: two Biomass Burning factors and a highly chemically processed Long Range Transport factor. The Biomass Burning factors were separated by PMF due to differences in chemical processing which were in part elucidated by the passage of two thunderstorm gust fronts with different air mass histories. The remaining two factors, ECOC Night and Nitrate Background, represented the night-time partitioning of nitrate to pre-existing particles of different origins. The distinct meteorological conditions observed during this month-long study in the summer of 2007 provided a unique

  11. Elucidating Mechanisms of Molecular Recognition Between Human Argonaute and miRNA Using Computational Approaches

    KAUST Repository

    Jiang, Hanlun

    2016-12-06

    MicroRNA (miRNA) and Argonaute (AGO) protein together form the RNA-induced silencing complex (RISC) that plays an essential role in the regulation of gene expression. Elucidating the underlying mechanism of AGO-miRNA recognition is thus of great importance not only for the in-depth understanding of miRNA function but also for inspiring new drugs targeting miRNAs. In this chapter we introduce a combined computational approach of molecular dynamics (MD) simulations, Markov state models (MSMs), and protein-RNA docking to investigate AGO-miRNA recognition. Constructed from MD simulations, MSMs can elucidate the conformational dynamics of AGO at biologically relevant timescales. Protein-RNA docking can then efficiently identify the AGO conformations that are geometrically accessible to miRNA. Using our recent work on human AGO2 as an example, we explain the rationale and the workflow of our method in details. This combined approach holds great promise to complement experiments in unraveling the mechanisms of molecular recognition between large, flexible, and complex biomolecules.

  12. Secretome analysis to elucidate metalloprotease-dependent ectodomain shedding of glycoproteins during neuronal differentiation.

    Science.gov (United States)

    Tsumagari, Kazuya; Shirakabe, Kyoko; Ogura, Mayu; Sato, Fuminori; Ishihama, Yasushi; Sehara-Fujisawa, Atsuko

    2017-02-01

    Many membrane proteins are subjected to limited proteolyses at their juxtamembrane regions, processes referred to as ectodomain shedding. Shedding ectodomains of membrane-bound ligands results in activation of downstream signaling pathways, whereas shedding those of cell adhesion molecules causes loss of cell-cell contacts. Secreted proteomics (secretomics) using high-resolution mass spectrometry would be strong tools for both comprehensive identification and quantitative measurement of membrane proteins that undergo ectodomain shedding. In this study, to elucidate the ectodomain shedding events that occur during neuronal differentiation, we establish a strategy for quantitative secretomics of glycoproteins released from differentiating neuroblastoma cells into culture medium with or without GM6001, a broad-spectrum metalloprotease inhibitor. Considering that most of transmembrane and secreted proteins are N-glycosylated, we include a process of N-glycosylated peptides enrichment as well as isotope tagging in our secretomics workflow. Our results show that differentiating N1E-115 neurons secrete numerous glycosylated polypeptides in metalloprotease-dependent manners. They are derived from cell adhesion molecules such as NCAM1, CADM1, L1CAM, various transporters and receptor proteins. These results show the landscape of ectodomain shedding and other secretory events in differentiating neurons and/or during axon elongation, which should help elucidate the mechanism of neurogenesis and the pathogenesis of neurological disorders. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  13. Elucidation and modulation of glucocorticoid-induced apoptosis in acute lymphoblastic leukemia cells

    International Nuclear Information System (INIS)

    Eberhart, K.

    2011-01-01

    This thesis deals with the elucidation of the synergistic effect of the glucocorticoid dexamethasone and the metabolic modulator 2-deoxyglucose on apoptosis induction in two in vitro model systems of childhood acute lymphoblastic leukemia. 2-deoxyglucose accelerated the kinetics of, and increased the sensitivity to, glucocorticoid-induced apoptosis in two leukemia cell lines. In primary lymphocytes from healthy donors, in contrast, 2-deoxyglucose and dexamethasone did not act synergistically on apoptosis induction. To elucidate the molecular basis of the synergistic effect, glycolysis by means of glucose uptake, lactate production, ATP levels, glucose transporter and hexokinase expression and mitochondrial oxygen consumption was analyzed in treated vs. untreated cells. The study revealed a downregulation of gene expression of the glucose transporter GLUT1 and hexokinase 2 (HK2), release of HK2 from the outer mitochondrial membrane, as well as reduced glycolysis and mitochondrial respiration. Moreover, the analysis of the mitochondrial proteome by 2 dimensional differential gel electrophoresis after treatment with 2-deoxyglucose and dexamethasone revealed the regulation of several interesting candidate proteins involved in treatment related apoptosis. (author)

  14. Elucidation of spin echo small angle neutron scattering correlation functions through model studies.

    Science.gov (United States)

    Shew, Chwen-Yang; Chen, Wei-Ren

    2012-02-14

    Several single-modal Debye correlation functions to approximate part of the overall Debey correlation function of liquids are closely examined for elucidating their behavior in the corresponding spin echo small angle neutron scattering (SESANS) correlation functions. We find that the maximum length scale of a Debye correlation function is identical to that of its SESANS correlation function. For discrete Debye correlation functions, the peak of SESANS correlation function emerges at their first discrete point, whereas for continuous Debye correlation functions with greater width, the peak position shifts to a greater value. In both cases, the intensity and shape of the peak of the SESANS correlation function are determined by the width of the Debye correlation functions. Furthermore, we mimic the intramolecular and intermolecular Debye correlation functions of liquids composed of interacting particles based on a simple model to elucidate their competition in the SESANS correlation function. Our calculations show that the first local minimum of a SESANS correlation function can be negative and positive. By adjusting the spatial distribution of the intermolecular Debye function in the model, the calculated SESANS spectra exhibit the profile consistent with that of hard-sphere and sticky-hard-sphere liquids predicted by more sophisticated liquid state theory and computer simulation. © 2012 American Institute of Physics

  15. Application of ion beams for elucidation of functions in living bodies

    International Nuclear Information System (INIS)

    Fujimura, Takashi; Ishihara, Noriyuki; Omichi, Hideki; Tamura, Mamoru; Omasa, Kenji; Sasaki, Yasuhito.

    1992-01-01

    The Japan Atomic Energy Research Institute (JAERI) is planning a research project, 'Application of Ion Beams for Elucidation of Functions in Living Bodies'. This project is characterized by the non-invasive or non-destructive measurement for living plants, animals and microorganisms and divided into two fields. The first field is the utilization of positron emitters prepared with cyclotron. The development of a new method which combines PET with other methods like near infrared region spectroscopy or magnetic resonance spectroscopy is urgently desired. Positron emitters can be also applied to elucidate the functions of plants. The second field is in situ and non-invasive optical measurement of living bodies or cells irradiated with ion beams. Active species produced by irradiation could induce physiological and biochemical reactions in living bodies or cells. To actualize this project, a group of non-invasive measuring equipments for the first field will be set in a new building next to ion irradiation facilities (TIARA, Takasaki Ion Accelerators for Advanced Radiation Application). For the second field, in situ and non-invasive optical measurement of living bodies or cells with be carried out in TIARA. (J.P.N.)

  16. Immunological assays employed for the elucidation of an histoplasmosis outbreak in São Paulo, SP

    Directory of Open Access Journals (Sweden)

    Angela Noronha Passos

    2014-12-01

    Full Text Available Several reports showed outbreaks of histoplasmosis acquired while bat-inhabited caves were visited by tourists, miners or researchers. We evaluated the performance of double immunodifusion (DI and immunoblotting (IB assays, employed for the histoplasmosis outbreak elucidation occurred in Vale do Paraíba, São Paulo. The existence of epidemiologic link, four patients with clinical signs