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Sample records for non-enzymatically glycated peptides

  1. Analyses of the in vitro non-enzymatic glycation of peptides/proteins by matrix-assisted laser desorption/ionization mass spectrometry

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    Lee, Bao-Shiang; Krishnanchettiar, Sangeeth; Lateef, Syed Salman; Gupta, Shalini

    2007-01-01

    Non-enzymatic glycation of proteins with the reducing agent glucose is implicated to be responsible for diabetes-derived complications, food browning, and aging. However, the non-enzymatic glycation process of peptides/proteins is not well understood and further research is needed to gain an understanding of the underlying principles involved in diabetes-related complications. In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is used to analyze the in vitro glycation of peptides/proteins. In addition to the physiological conditions, harsh conditions (higher concentration of glucose, higher or lower pH, and higher temperature) are also used in this study. Peptides/proteins are reacted with glucose for up to 120 h at 4 [degree sign]C, 37 [degree sign]C, or 65 [degree sign]C. Single and/or multiple glycations are observed using broad pH conditions (from 10% TFA with pKa of 0.5 to pH 10) at various glucose concentrations (from 0.01 M to 1 M). Data suggest that glucose reacts readily with both peptides and proteins, and the efficiency of the glycation increases with higher temperature, higher pH, higher glucose concentration, or longer incubation time. However, influence of the buffer pH on the efficiency of the glycation of peptides is less pronounced compared to that of proteins. This effect could result from denaturation of proteins at higher pH and the resultant exposure of potential glycation sites. This data could lead to the inference that the glycation process of peptides/proteins would occur but proceed very slowly under the diabetes conditions in vivo (37 [degree sign]C, ~neutral pH, ~0.007 M glucose). Postsource decay and MS/MS results of singly glycated angiotensin I, P14R (PPPPPPPPPPPPPPR), and human adrenocorticotropic hormone (ATCH) fragments 1-13 indicate that glucose reacts with the amino group of the N-terminal of ATCH 1-13 and the guanidino group of the arginine residue of both angiotensin I and P14R.

  2. Monitoring the progress of non-enzymatic glycation in vitro

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    Shaw, S.M.; Crabbe, M.J.

    1994-01-01

    The progress of in vitro non-enzymatic glycation of bovine serum albumin was followed by using 14 C-glucose and a nitroblue tetrazolium assay, absorption and fluorescence spectroscopy, SDS gel electrophoresis and protease digestion. The number of adducts detectable using both 14 C-tracers and a fructosamine assay remained low at physiological glucose concentrations, fewer than five adducts being detectable. When glucose concentrations > 1.0 M were used the number of adducts was found to greatly exceed the number of lysyl residues available in BSA, indicative of cross-linking between Maillard products. Incubation of BSA with glucose concentrations of up to 160 mM for one month produced no observable increase in molecular weight by SDS gel electrophoresis, showing that at physiological glucose concentrations, increases in molecular weight were minimal for short incubation periods. Increases in absorption were proportial to both the glucose concentration and the incubation time. Several absorption peaks, at 370, 488 and 554 nm, were consistent in appearance throughout the course of each incubation. Fluorescence spectroscopy of the modified proteins showed a disappearance of the fluorescence associated with peptide bonds and aromatic residues and the appearance of a broad peak at longer wavelengths due to the wide range of absorptive/fluorescent wavelengths of the developing Maillard products. Protease digestion gave similar patterns with non-glycated and glycated protein, suggesting that glycation did not block digestion sites, and that partial digestion did not cause significant further exposure of susceptible sites. Our results show that while glycation ultimately results in protein conformational changes and the formation of large molecular weight species, these occur at a relatively late stage in the maturation of protein Maillard products, after ≥ nine months of incubation with glucose concentration of ≥ 20 mM. Monitoring of AGE maturation in vitro is better

  3. Effects of non-enzymatic glycation in human serum albumin. Spectroscopic analysis

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    Szkudlarek, A.; Sułkowska, A.; Maciążek-Jurczyk, M.; Chudzik, M.; Równicka-Zubik, J.

    2016-01-01

    Human serum albumin (HSA), transporting protein, is exposed during its life to numerous factors that cause its functions become impaired. One of the basic factors - glycation of HSA - occurs in diabetes and may affect HSA-drug binding. Accumulation of advanced glycation end-products (AGEs) leads to diseases e.g. diabetic and non-diabetic cardiovascular diseases, Alzheimer disease, renal disfunction and in normal aging. The aim of the present work was to estimate how non-enzymatic glycation of human serum albumin altered its tertiary structure using fluorescence technique. We compared glycated human serum albumin by glucose (gHSAGLC) with HSA glycated by fructose (gHSAFRC). We focused on presenting the differences between gHSAFRC and nonglycated (HSA) albumin used acrylamide (Ac), potassium iodide (KI) and 2-(p-toluidino)naphthalene-6-sulfonic acid (TNS). Changes of the microenvironment around the tryptophan residue (Trp-214) of non-glycated and glycated proteins was investigated by the red-edge excitation shift method. Effect of glycation on ligand binding was examined by the binding of phenylbutazone (PHB) and ketoprofen (KP), which a primary high affinity binding site in serum albumin is subdomain IIA and IIIA, respectively. At an excitation and an emission wavelength of λex 335 nm and λem 420 nm, respectively the increase of fluorescence intensity and the blue-shift of maximum fluorescence was observed. It indicates that the glycation products decreases the polarity microenvironment around the fluorophores. Analysis of red-edge excitation shift method showed that the red-shift for gHSAFRC is higher than for HSA. Non-enzymatic glycation also caused, that the Trp residue of gHSAFRC becomes less accessible for the negatively charged quencher (I-), KSV value is smaller for gHSAFRC than for HSA. TNS fluorescent measurement demonstrated the decrease of hydrophobicity in the glycated albumin. KSV constants for gHSA-PHB systems are higher than for the unmodified serum

  4. Effects of non-enzymatic glycation in human serum albumin. Spectroscopic analysis.

    Science.gov (United States)

    Szkudlarek, A; Sułkowska, A; Maciążek-Jurczyk, M; Chudzik, M; Równicka-Zubik, J

    2016-01-05

    Human serum albumin (HSA), transporting protein, is exposed during its life to numerous factors that cause its functions become impaired. One of the basic factors --glycation of HSA--occurs in diabetes and may affect HSA-drug binding. Accumulation of advanced glycation end-products (AGEs) leads to diseases e.g. diabetic and non-diabetic cardiovascular diseases, Alzheimer disease, renal disfunction and in normal aging. The aim of the present work was to estimate how non-enzymatic glycation of human serum albumin altered its tertiary structure using fluorescence technique. We compared glycated human serum albumin by glucose (gHSA(GLC)) with HSA glycated by fructose (gHSA(FRC)). We focused on presenting the differences between gHSA(FRC) and nonglycated (HSA) albumin used acrylamide (Ac), potassium iodide (KI) and 2-(p-toluidino)naphthalene-6-sulfonic acid (TNS). Changes of the microenvironment around the tryptophan residue (Trp-214) of non-glycated and glycated proteins was investigated by the red-edge excitation shift method. Effect of glycation on ligand binding was examined by the binding of phenylbutazone (PHB) and ketoprofen (KP), which a primary high affinity binding site in serum albumin is subdomain IIA and IIIA, respectively. At an excitation and an emission wavelength of λex 335nm and λem 420nm, respectively the increase of fluorescence intensity and the blue-shift of maximum fluorescence was observed. It indicates that the glycation products decreases the polarity microenvironment around the fluorophores. Analysis of red-edge excitation shift method showed that the red-shift for gHSA(FRC) is higher than for HSA. Non-enzymatic glycation also caused, that the Trp residue of gHSA(FRC) becomes less accessible for the negatively charged quencher (I(-)), KSV value is smaller for gHSA(FRC) than for HSA. TNS fluorescent measurement demonstrated the decrease of hydrophobicity in the glycated albumin. KSV constants for gHSA-PHB systems are higher than for the

  5. Destructive effect of non-enzymatic glycation on catalase and remediation via curcumin.

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    Mofidi Najjar, Fayezeh; Taghavi, Fereshteh; Ghadari, Rahim; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2017-09-15

    Non-enzymatic glycation of proteins is a post-translational modification that is produced by a covalent binding between reducing sugars and amino groups of lysine and arginine residues. In this paper the effect of pathological conditions, derived from hyperglycemia on bovine liver catalase (BLC) as a model protein was considered by measuring enzyme activity, reactive oxygen species (ROS) generation, and changes in catalase conformational properties. We observed that in the presence of glucose, the catalase activity gradually decreased. ROS generation was also involved in the glycation process. Thus, decreased BLC activity was partly considered as a result of ROS generation through glycation. However, in the presence of curcumin the amount of ROS was reduced resulting in increased activity of the glycated catalase. The effect of high glucose level and the potential inhibitory effect of curcumin on aggregation and structural changes of catalase were also investigated. Molecular dynamic simulations also showed that interaction of catalase with curcumin resulted in changes in accessible surface area (ASA) and pKa, two effective parameters of glycation, in potential glycation lysine residues. Thus, the decrease in ASA and increase in pKa of important lysine residues were considered as predominant factors in decreased glycation of BLC by curcumin. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Comprehensive Identification of Glycated Peptides and Their Glycation Motifs in Plasma and Erythrocytes of Control and Diabetic Subjects

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    Zhang, Qibin; Monroe, Matthew E.; Schepmoes, Athena A.; Clauss, Therese RW; Gritsenko, Marina A.; Meng, Da; Petyuk, Vladislav A.; Smith, Richard D.; Metz, Thomas O.

    2011-07-01

    Non-enzymatic glycation of proteins is implicated in diabetes mellitus and its related complications. In this report, we extend our previous development and refinement of proteomics-based methods for the analysis of non-enzymatically glycated proteins to comprehensively identify glycated proteins in normal and diabetic human plasma and erythrocytes. Using immunodepletion, enrichment, and fractionation strategies, we identified 7749 unique glycated peptides, corresponding to 3742 unique glycated proteins. Semi-quantitative comparisons revealed a number of proteins with glycation levels significantly increased in diabetes relative to control samples and that erythrocyte proteins are more extensively glycated than plasma proteins. A glycation motif analysis revealed amino acids that are favored more than others in the protein primary structures in the vicinity of the glycation sites in both sample types. The glycated peptides and corresponding proteins reported here provide a foundation for the potential identification of novel markers for diabetes, glycemia, or diabetic complications.

  7. Understanding non-enzymatic aminophospholipid glycation and its inhibition. Polar head features affect the kinetics of Schiff base formation.

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    Caldés, Catalina; Vilanova, Bartolomé; Adrover, Miquel; Muñoz, Francisco; Donoso, Josefa

    2011-08-01

    Non-enzymatic aminophospholipid glycation is an especially important process because it alters the stability of lipid bilayers and interferes with cell function and integrity as a result. However, the kinetic mechanism behind this process has scarcely been studied. As in protein glycation, the process has been suggested to involve the formation of a Schiff base as the initial, rate-determining step. In this work, we conducted a comparative kinetic study of Schiff base formation under physiological conditions in three low-molecular weight analogues of polar heads in the naturally occurring aminophospholipids O-phosphorylethanolamine (PEA), O-phospho-DL-serine (PSer) and 2-aminoethylphenethylphosphate (APP) with various glycating carbonyl compounds (glucose, arabinose and acetol) and the lipid glycation inhibitor pyridoxal 5'-phosphate (PLP). Based on the results, the presence of a phosphate group and a carboxyl group in α position respect to the amino group decrease the formation constant for the Schiff base relative to amino acids. On the other hand, esterifying the phosphate group with a non-polar substituent in APP increases the stability of its Schiff base. The observed kinetic formation constants of aminophosphates with carbonyl groups were smaller than those for PLP. Our results constitute an important contribution to understanding the competitive inhibition effect of PLP on aminophospholipid glycation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Vanillin restrains non-enzymatic glycation and aggregation of albumin by chemical chaperone like function.

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    Awasthi, Saurabh; Saraswathi, N T

    2016-06-01

    Vanillin a major component of vanilla bean extract is commonly used a natural flavoring agent. Glycation is known to induce aggregation and fibrillation of globular proteins such as albumin, hemoglobin. Here we report the inhibitory potential of vanillin toward early and advanced glycation modification and amyloid like aggregation of albumin based on the determination of both early and advanced glycation and conformational changes in albumin using circular dichroism. Inhibition of aggregation and fibrillation of albumin was determined based on amyloid specific dyes i.e., Congo red and Thioflavin T and microscopic imaging. It was evident that vanillin restrains glycation of albumin and exhibits protective effect toward its native conformation. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Application of Ni(II-assisted peptide bond hydrolysis to non-enzymatic affinity tag removal.

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    Edyta Kopera

    Full Text Available In this study, we demonstrate a non-enzymatic method for hydrolytic peptide bond cleavage, applied to the removal of an affinity tag from a recombinant fusion protein, SPI2-SRHWAP-His(6. This method is based on a highly specific Ni(II reaction with (S/TXHZ peptide sequences. It can be applied for the protein attached to an affinity column or to the unbound protein in solution. We studied the effect of pH, temperature and Ni(II concentration on the efficacy of cleavage and developed an analytical protocol, which provides active protein with a 90% yield and ∼100% purity. The method works well in the presence of non-ionic detergents, DTT and GuHCl, therefore providing a viable alternative for currently used techniques.

  10. Bimolecular interaction of argpyrimidine (a Maillard reaction product) in in vitro non-enzymatic protein glycation model and its potential role as an antiglycating agent.

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    Bhattacherjee, Abhishek; Dhara, Kaliprasanna; Chakraborti, Abhay Sankar

    2017-09-01

    Non- enzymatic glycation, also known as Maillard reaction, is one of the most important and investigated reactions in biochemistry. Maillard reaction products (MRPs) like protein-derived advanced glycation end products (AGEs) are often referred to cause pathophysiological complications in human systems. On contrary, several MRPs are exogenously used as antioxidant, antimicrobial and flavouring agents. In the preset study, we have shown that argpyrimidine, a well-established AGE, interacts with bovine serum albumin (BSA) and glucose individually in standard BSA-glucose model system and successfully inhibits glycation of the protein. Bimolecular interaction of argpyrimidine with glucose or BSA has been studied independently. Chromatographic purification, different spectroscopic studies and molecular modeling have been used to evaluate the nature and pattern of interactions. Binding of argpyrimidine with BSA prevents incorporation of glucose inside the native protein. Argpyrimidine can also directly entrap glucose. Both these interactions may be associated with the antiglycation potential of argpyrimidine, indicating a beneficial function of an AGE. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Non-enzymatic glycation enhances human serum albumin binding capacity to sodium fluorescein at room temperature: A spectroscopic analysis.

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    Fatima, Sadaf; Anwar, Tamanna; Ahmad, Nabeel; Islam, Asimul; Sen, Priyankar

    2017-06-01

    Sodium fluorescein (SF) is a fluorescent tracer dye used extensively in diagnostic tools in the field of Ophthalmology, particularly in intravenous fluorescein angiography (IVFA). The binding of SF to human serum albumin (HSA) has been predicted by molecular docking and investigated by circular dichroism (CD) and fluorescence spectroscopy with or without glycation at temperatures 296, 301, and 310K. The binding parameters were calculated by quenching of emission spectrum of a constant concentration of SF (2μmol/l) at 513nm against increasing concentrations of glycated or unmodified HSA as quencher starting from stoichiometry ratio of 1:1. The HSA-SF interaction found to be a static binding. The Stern-Volmer constants (Ksv) were in the range of ~10 4 M -1 and other thermodynamic parameters like enthalpy (ΔH°), free energy (ΔG°) and entropy (ΔS°) are similar to albumin ligand bindings reported by previous workers. The interactions were found to be spontaneous, irrespective of temperature or glycation. Glycated HSA is clinically used to monitor unstable glycemic controls in diabetic patients. A 39% increase in binding affinity (log K) and free energy (ΔG°) is reported on glycation at 310K (room temperature), which may be important in the SF based angiographies. On glycation HSA-SF binding appears to change from an enthalpy-driven to an entropy-driven reaction. SF shows best binding to FA binding site III of HSA, which also overlaps with drug binding site II of subdomain IIIA. Leu430 seems to play a pivotal role in the interaction. Copyright © 2017. Published by Elsevier B.V.

  12. PSEUDOAFFINITY CHROMATOGRAPHY ENRICHMENT OF GLYCATED PEPTIDES FOR MONITORING ADVANCED GLYCATION END PRODUCTS (AGES IN METABOLIC DISORDERS

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    Rajasekar R. Prasanna

    2016-09-01

    Full Text Available Advanced Glycation End (AGE products are produced due to diabetic progression and they are responsible for many complications in the diabetic disorder. The diabetic progression is measured, particularly following glycated hemoglobin using specific antibodies. However, the most abundant protein in blood, human serum albumin, is also found to be glycated which has a much shorter half life and gives information on short term glycemic control. In addition, glycated albumins are considered as markers of diabetic complications such as nephropathy, peripheral vascular calcification and also in Alzheimer’s disease. The glycation proceeds from the interaction between aldehyde group of sugar and the free amino group of the protein, resulting in the formation of Schiff’s base, which undergoes a series of modifications leading to generation of imidazoyl derivatives of amino acids known as Amadori rearrangement products. The imidazoyl derivatives from arginine and lysine are the most prominent modifications observed in proteins in the presence of reducing sugar and these imidazoyl derivatives have an affinity towards certain transition metal ions. Based on our earlier exhaustive work on trapping the histidine peptides using transition metal ion, Cu(II linked to imino-diacetate complex, we explored Cu(II immobilized metal affinity chromatography (IMAC as a potential tool for specific detection of glycated peptides of human serum albumin. Our results clearly demonstrate that Cu(II IMAC is able to detect glycated peptides very efficiently while the non-glycated forms were not retained on the Cu (II column as confirmed by LC-MS/MS analysis. We further discuss the utility of IMAC technology to enrich the detection of AGE products in plasma. We anticipate that these studies may provide valuable information on understanding disease pathologies and the potential of AGE products as biomarkers of various diseases including neurodegenerative, renal and

  13. A Perspective on Reagent Diversity and Non-covalent Binding of Reactive Carbonyl Species (RCS and Effector Reagents in Non-enzymatic Glycation (NEG: Mechanistic Considerations and Implications for Future Research

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    Kenneth J. Rodnick

    2017-06-01

    Full Text Available This perspective focuses on illustrating the underappreciated connections between reactive carbonyl species (RCS, initial binding in the nonenzymatic glycation (NEG process, and nonenzymatic covalent protein modification (here termed NECPM. While glucose is the central species involved in NEG, recent studies indicate that the initially-bound glucose species in the NEG of human hemoglobin (HbA and human serum albumin (HSA are non-RCS ring-closed isomers. The ring-opened glucose, an RCS structure that reacts in the NEG process, is most likely generated from previously-bound ring-closed isomers undergoing concerted acid/base reactions while bound to protein. The generation of the glucose RCS can involve concomitantly-bound physiological species (e.g., inorganic phosphate, water, etc.; here termed effector reagents. Extant NEG schemes do not account for these recent findings. In addition, effector reagent reactions with glucose in the serum and erythrocyte cytosol can generate RCS (e.g., glyoxal, glyceraldehyde, etc.. Recent research has shown that these RCS covalently modify proteins in vivo via NECPM mechanisms. A general scheme that reflects both the reagent and mechanistic diversity that can lead to NEG and NECPM is presented here. A perspective that accounts for the relationships between RCS, NEG, and NECPM can facilitate the understanding of site selectivity, may help explain overall glycation rates, and may have implications for the clinical assessment/control of diabetes mellitus. In view of this perspective, concentrations of ribose, fructose, Pi, bicarbonate, counter ions, and the resulting RCS generated within intracellular and extracellular compartments may be of importance and of clinical relevance. Future research is also proposed.

  14. Annona muricata Linn. leaf as a source of antioxidant compounds with in vitro antidiabetic and inhibitory potential against α-amylase, α-glucosidase, lipase, non-enzymatic glycation and lipid peroxidation.

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    Justino, Allisson Benatti; Miranda, Natália Carnevalli; Franco, Rodrigo Rodrigues; Martins, Mário Machado; Silva, Neide Maria da; Espindola, Foued Salmen

    2018-04-01

    Annona muricata leaves are used in traditional medicine to manage diabetes mellitus and its complications. The aim of this study was to evaluate the potential in vitro antidiabetic properties of Annona muricata leaf by identifying its main phytochemical constituents and characterizing the phenolic-enriched fractions for their in vitro antioxidant capacity and inhibitory activities against glycoside and lipid hydrolases, advanced glycation end-product formation and lipid peroxidation. Ethanol extract of A. muricata leaf was subjected to a liquid-liquid partitioning and its fractions were used in enzymatic assays to evaluate their inhibitory potential against α-amylase, α-glucosidase and lipase, as well as their antioxidant (DPPH, ORAC, FRAP and Fe 2+ -ascorbate-induced lipid peroxidation assays) and anti-glycation (BSA-fructose, BSA-methylglyoxal and arginine-methylglyoxal models) capacities. In addition, identification of the main bioactive compounds of A. muricata leaf by HPLC-ESI-MS/MS analysis was carried out. Ethyl acetate (EtOAc) and n-butanol (BuOH) fractions showed, respectively, antioxidant properties (ORAC 3964 ± 53 and 2707 ± 519 μmol trolox eq g -1 , FRAP 705 ± 35 and 289 ± 18 μmol trolox eq g -1 , and DPPH IC 50 4.3 ± 0.7 and 9.3 ± 0.8 μg mL -1 ) and capacity to reduce liver lipid peroxidation (p muricata, which contributes to the understanding of the potential effectiveness in the use of the A. muricata leaf, especially its polyphenols-enriched fractions, for the management of diabetes mellitus and its complications. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  15. A novel monoclonal antibody targeting carboxymethyllysine, an advanced glycation end product in atherosclerosis and pancreatic cancer.

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    Ulrika Wendel

    Full Text Available Advanced glycation end products are formed by non-enzymatic reactions between proteins and carbohydrates, causing irreversible lysine and arginine alterations that severely affect protein structure and function. The resulting modifications induce inflammation by binding to scavenger receptors. An increase in advanced glycation end products is observed in a number of diseases e.g. atherosclerosis and cancer. Since advanced glycation end products also are present in healthy individuals, their detection and quantification are of great importance for usage as potential biomarkers. Current methods for advanced glycation end product detection are though limited and solely measure total glycation. This study describes a new epitope-mapped single chain variable fragment, D1-B2, against carboxymethyllysine, produced from a phage library that was constructed from mouse immunizations. The phage library was selected against advanced glycation end product targets using a phage display platform. Characterization of its binding pattern was performed using large synthetic glycated peptide and protein libraries displayed on microarray slides. D1-B2 showed a preference for an aspartic acid, three positions N-terminally from a carboxymethyllysine residue and also bound to a broad collection of glycated proteins. Positive immunohistochemical staining of mouse atherosclerotic plaques and of a tissue microarray of human pancreatic tumors confirmed the usability of the new scFv for advanced glycation end product detection in tissues. This study demonstrates a promising methodology for high-throughput generation of epitope-mapped monoclonal antibodies against AGE.

  16. Glucagon-like peptide-1 counteracts the detrimental effects of Advanced Glycation End-Products in the pancreatic beta cell line HIT-T 15

    International Nuclear Information System (INIS)

    Puddu, A.; Storace, D.; Durante, A.; Odetti, P.; Viviani, G.L.

    2010-01-01

    Research highlights: → GLP-1 prevents AGEs-induced cell death. → GLP-1 prevents AGEs-induced oxidative stress. → GLP-1 ameliorated AGEs-induced cell dysfunction. → GLP-1 attenuates AGEs-induced RAGE increment. → GLP-1 counteracts AGEs-induced pancreatic cell death and dysfunction. -- Abstract: Advanced Glycation End-Products (AGEs), a group of compounds resulting from the non-enzymatic reaction of reducing sugars with the free amino group of proteins, are implicated in diabetic complications. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T 15 to high concentrations of AGEs significantly decreases cell proliferation and insulin secretion, and affects transcription factors regulating insulin gene transcription. The glucagon-like peptide-1 (GLP-1) is an incretin hormone that increases proinsulin biosynthesis, stimulates insulin secretion, and improves pancreatic beta-cell viability. The aim of this work was to investigate the effects of GLP-1 on the function and viability of HIT-T 15 cells cultured with AGEs. HIT-T 15 cells were cultured for 5 days in presence of AGEs alone, or supplemented with 10 nmol/l GLP-1. Cell viability, insulin secretion, redox balance, and expression of the AGEs receptor (RAGE) were then determined. The results showed that GLP-1 protected beta cell against AGEs-induced cell death preventing both apoptosis and necrosis. Moreover, addition of GLP-1 to the AGEs culture medium restored the redox balance, improved the responsiveness to glucose, and attenuated AGEs-induced RAGE expression. These findings provide evidence that GLP-1 protects beta cells from the dangerous effects of AGEs.

  17. Assessment of collagen quality associated with non-enzymatic cross-links in human bone using Fourier-transform infrared imaging.

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    Schmidt, F N; Zimmermann, E A; Campbell, G M; Sroga, G E; Püschel, K; Amling, M; Tang, S Y; Vashishth, D; Busse, B

    2017-04-01

    Aging and many disease conditions, most notably diabetes, are associated with the accumulation of non-enzymatic cross-links in the bone matrix. The non-enzymatic cross-links, also known as advanced glycation end products (AGEs), occur at the collagen tissue level, where they are associated with reduced plasticity and increased fracture risk. In this study, Fourier-transform infrared (FTIR) imaging was used to detect spectroscopic changes associated with the formation of non-enzymatic cross-links in human bone collagen. Here, the non-enzymatic cross-link profile was investigated in one cohort with an in vitro ribose treatment as well as another cohort with an in vivo bisphosphonate treatment. With FTIR imaging, the two-dimensional (2D) spatial distribution of collagen quality associated with non-enzymatic cross-links was measured through the area ratio of the 1678/1692cm -1 subbands within the amide I peak, termed the non-enzymatic crosslink-ratio (NE-xLR). The NE-xLR increased by 35% in the ribation treatment group in comparison to controls (p<0.005), with interstitial bone tissue being more susceptible to the formation of non-enzymatic cross-links. Ultra high-performance liquid chromatography, fluorescence microscopy, and fluorometric assay confirm a correlation between the non-enzymatic cross-link content and the NE-xLR ratio in the control and ribated groups. High resolution FTIR imaging of the 2D bone microstructure revealed enhanced accumulation of non-enzymatic cross-links in bone regions with higher tissue age (i.e., interstitial bone). This non-enzymatic cross-link ratio (NE-xLR) enables researchers to study not only the overall content of AGEs in the bone but also its spatial distribution, which varies with skeletal aging and diabetes mellitus and provides an additional measure of bone's propensity to fracture. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Electrochemical non-enzymatic glucose sensors

    International Nuclear Information System (INIS)

    Park, Sejin; Boo, Hankil; Chung, Taek Dong

    2006-01-01

    The electrochemical determination of glucose concentration without using enzyme is one of the dreams that many researchers have been trying to make come true. As new materials have been reported and more knowledge on detailed mechanism of glucose oxidation has been unveiled, the non-enzymatic glucose sensor keeps coming closer to practical applications. Recent reports strongly imply that this progress will be accelerated in 'nanoera'. This article reviews the history of unraveling the mechanism of direct electrochemical oxidation of glucose and making attempts to develop successful electrochemical glucose sensors. The electrochemical oxidation of glucose molecules involves complex processes of adsorption, electron transfer, and subsequent chemical rearrangement, which are combined with the surface reactions on the metal surfaces. The information about the direct oxidation of glucose on solid-state surfaces as well as new electrode materials will lead us to possible breakthroughs in designing the enzymeless glucose sensing devices that realize innovative and powerful detection. An example of those is to introduce nanoporous platinum as an electrode, on which glucose is oxidized electrochemically with remarkable sensitivity and selectivity. Better model of such glucose sensors is sought by summarizing and revisiting the previous reports on the electrochemistry of glucose itself and new electrode materials

  19. Separation of tryptic peptides of native and glycated BSA using open-tubular CEC with salophene-lanthanide-Zn2+ complex as stationary phase

    Czech Academy of Sciences Publication Activity Database

    Sedláková, Pavla; Eckhardt, Adam; Lacinová, Kateřina; Pataridis, Statis; Mikšík, Ivan; Král, V.; Kašička, Václav

    2009-01-01

    Roč. 32, č. 22 (2009), s. 3930-3935 ISSN 1615-9306 R&D Projects: GA ČR GA203/09/0675; GA ČR(CZ) GA203/08/1428; GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z40550506 Keywords : glycation * open- tubular CEC * peptide mapping Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.551, year: 2009

  20. An Emerging Role of Glucagon-Like Peptide-1 in Preventing Advanced-Glycation-End-Product-Mediated Damages in Diabetes

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    Alessandra Puddu

    2013-01-01

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a gut hormone produced in the intestinal epithelial endocrine L cells by differential processing of the proglucagon gene. Released in response to the nutrient ingestion, GLP-1 plays an important role in maintaining glucose homeostasis. GLP-1 has been shown to regulate blood glucose levels by stimulating glucose-dependent insulin secretion and inhibiting glucagon secretion, gastric emptying, and food intake. These antidiabetic activities highlight GLP-1 as a potential therapeutic molecule in the clinical management of type 2 diabetes, (a disease characterized by progressive decline of beta-cell function and mass, increased insulin resistance, and final hyperglycemia. Since chronic hyperglycemia contributed to the acceleration of the formation of Advanced Glycation End-Products (AGEs, a heterogeneous group of compounds derived from the nonenzymatic reaction of reducing sugars with free amino groups of proteins implicated in vascular diabetic complications, the administration of GLP-1 might directly counteract diabetes pathophysiological processes (such as pancreatic β-cell dysfunction. This paper outlines evidence on the protective role of GLP-1 in preventing the deleterious effects mediated by AGEs in type 2 diabetes.

  1. Sulfate radicals enable a non-enzymatic Krebs cycle precursor.

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    Keller, Markus A; Kampjut, Domen; Harrison, Stuart A; Ralser, Markus

    2017-03-13

    The evolutionary origins of the tricarboxylic acid cycle (TCA), or Krebs cycle, are so far unclear. Despite a few years ago, the existence of a simple non-enzymatic Krebs-cycle catalyst has been dismissed 'as an appeal to magic', citrate and other intermediates have meanwhile been discovered on a carbonaceous meteorite and do interconvert non-enzymatically. To identify the non-enzymatic Krebs cycle catalyst, we used combinatorial, quantitative high-throughput metabolomics to systematically screen iron and sulfate reaction milieus that orient on Archean sediment constituents. TCA cycle intermediates are found stable in water and in the presence of most iron and sulfate species, including simple iron-sulfate minerals. However, we report that TCA intermediates undergo 24 interconversion reactions in the presence of sulfate radicals that form from peroxydisulfate. The non-enzymatic reactions critically cover a topology as present in the Krebs cycle, the glyoxylate shunt and the succinic semialdehyde pathways. Assembled in a chemical network, the reactions achieve more than ninety percent carbon recovery. Our results show that a non-enzymatic precursor for the Krebs cycle is biologically sensible, efficient, and forms spontaneously in the presence of sulfate radicals.

  2. Stimulatory effects of advanced glycation endproducts (AGEs) on fibronectin matrix assembly.

    Science.gov (United States)

    Pastino, Alexandra K; Greco, Todd M; Mathias, Rommel A; Cristea, Ileana M; Schwarzbauer, Jean E

    2017-05-01

    Advanced glycation endproducts (AGEs) are a heterogeneous group of compounds that form via non-enzymatic glycation of proteins throughout our lifespan and at a higher rate in certain chronic diseases such as diabetes. AGEs contribute to the progression of fibrosis, in part by stimulating cellular pathways that affect gene expression. Long-lived ECM proteins are targets for non-enzymatic glycation but the question of whether the AGE-modified ECM leads to excess ECM accumulation and fibrosis remains unanswered. In this study, cellular changes due to AGE accretion in the ECM were investigated. Non-enzymatic glycation of proteins in a decellularized fibroblast ECM was achieved by incubating the ECM in a solution of methylglyoxal (MGO). Mass spectrometry of fibronectin (FN) isolated from the glycated matrix identified twenty-eight previously unidentified MGO-derived AGE modification sites including functional sites such as the RGD integrin-binding sequence. Mesangial cells grown on the glycated, decellularized matrix assembled increased amounts of FN matrix. Soluble AGE-modified bovine serum albumin (BSA) also stimulated FN matrix assembly and this effect was reduced by function-blocking antibodies against the receptor for AGE (RAGE). These results indicate that cells respond to AGEs by increasing matrix assembly and that RAGE is involved in this response. This raises the possibility that the accumulation of ECM during the progression of fibrosis may be enhanced by cell interactions with AGEs on a glycated ECM. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Non-enzymatic glucosylation induced neo-epitopes on human serum albumin: A concentration based study.

    Directory of Open Access Journals (Sweden)

    Km Neelofar

    Full Text Available Hyperglycaemia induced non enzymatic glycation is accelerated in diabetic patients and aggressively involved in diabetes progression. Human serum albumin (HSA is the most abundant protein in blood circulation. In hyperglycaemia, it undergoes fast glycation and results in the impairment of structure. Our previous study has demonstrated structural alterations in Amadori-albumin modified with different glucose concentrations from physiological to pathophysiological range. Here, we focused on immunological characterization of Amadori-albumin. Immunogenicity of Amadori-albumin was analysed by direct binding and competitive ELISA. Amadori-albumin was found to be highly immunogenic (expect albumin modified with 5mM and induced high titre antibodies depending upon the extent of modification. Very high titre antibodies were obtained with albumin modified with 75mM glucose as compared to native albumin. Anti-Amadori-albumin-IgG from rabbit sera exhibited increased recognition of Amadori-albumin than native albumin in competitive immunoassay. Alteration induced in albumin after glucosylation has made it highly immunogenic. Induced antibodies were quite specific for respective immunogens but showed cross-reaction with other Amadori/native proteins. It suggests that glucosylation has generated highly immunogenic epitopes on albumin. Formation of high molecular weight immune complex with retarded mobility further supports specificity of anti-Amadori-albumin-IgG towards Amadori-albumin. It may be concluded that due to early glycation, an array of modification occurred in HSA structure. Such gross structural changes might favour polymerization of most of the native epitopes into potent immunogenic neo-epitopes, but some original epitopes were still active and has contributed in the immunogenicity. It could be concluded that induction of anti-Amadori-albumin antibodies may be due to protection of glucose modified albumin from protiolytic breakdown. We assumed

  4. Non-enzymatic glucosylation induced neo-epitopes on human serum albumin: A concentration based study.

    Science.gov (United States)

    Neelofar, Km; Arif, Zarina; Ahmad, Jamal; Alam, Khursheed

    2017-01-01

    Hyperglycaemia induced non enzymatic glycation is accelerated in diabetic patients and aggressively involved in diabetes progression. Human serum albumin (HSA) is the most abundant protein in blood circulation. In hyperglycaemia, it undergoes fast glycation and results in the impairment of structure. Our previous study has demonstrated structural alterations in Amadori-albumin modified with different glucose concentrations from physiological to pathophysiological range. Here, we focused on immunological characterization of Amadori-albumin. Immunogenicity of Amadori-albumin was analysed by direct binding and competitive ELISA. Amadori-albumin was found to be highly immunogenic (expect albumin modified with 5mM) and induced high titre antibodies depending upon the extent of modification. Very high titre antibodies were obtained with albumin modified with 75mM glucose as compared to native albumin. Anti-Amadori-albumin-IgG from rabbit sera exhibited increased recognition of Amadori-albumin than native albumin in competitive immunoassay. Alteration induced in albumin after glucosylation has made it highly immunogenic. Induced antibodies were quite specific for respective immunogens but showed cross-reaction with other Amadori/native proteins. It suggests that glucosylation has generated highly immunogenic epitopes on albumin. Formation of high molecular weight immune complex with retarded mobility further supports specificity of anti-Amadori-albumin-IgG towards Amadori-albumin. It may be concluded that due to early glycation, an array of modification occurred in HSA structure. Such gross structural changes might favour polymerization of most of the native epitopes into potent immunogenic neo-epitopes, but some original epitopes were still active and has contributed in the immunogenicity. It could be concluded that induction of anti-Amadori-albumin antibodies may be due to protection of glucose modified albumin from protiolytic breakdown. We assumed that this type of

  5. Involvement of formyl peptide receptors in receptor for advanced glycation end products (RAGE - and amyloid beta 1-42-induced signal transduction in glial cells

    Directory of Open Access Journals (Sweden)

    Slowik Alexander

    2012-11-01

    Full Text Available Abstract Background Recent studies suggest that the chemotactic G-protein-coupled-receptor (GPCR formyl-peptide-receptor-like-1 (FPRL1 and the receptor-for-advanced-glycation-end-products (RAGE play an important role in the inflammatory response involved in neurodegenerative disorders such as Alzheimer’s disease (AD. Therefore, the expression and co-localisation of mouse formyl peptide receptor (mFPR 1 and 2 as well as RAGE in an APP/PS1 transgenic mouse model using immunofluorescence and real-time RT-PCR were analysed. The involvement of rat or human FPR1/FPRL1 (corresponds to mFPR1/2 and RAGE in amyloid-β 1–42 (Aβ1-42-induced signalling were investigated by extracellular signal regulated kinase 1/2 (ERK1/2 phosphorylation. Furthermore, the cAMP level in primary rat glial cells (microglia and astrocytes and transfected HEK 293 cells was measured. Formyl peptide receptors and RAGE were inhibited by a small synthetic antagonist WRW4 and an inactive receptor variant delta-RAGE, lacking the intracytoplasmatic domains. Results We demonstrated a strong increase of mFPR1/2 and RAGE expression in the cortex and hippocampus of APP/PS1 transgenic mice co-localised to the glial cells. In addition, the Aβ1-42-induced signal transduction is dependant on FPRL1, but also on FPR1. For the first time, we have shown a functional interaction between FPRL1/FPR1 and RAGE in RAGE ligands S100B- or AGE-mediated signalling by ERK1/2 phosphorylation and cAMP level measurement. In addition a possible physical interaction between FPRL1 as well as FPR1 and RAGE was shown with co-immunoprecipitation and fluorescence microscopy. Conclusions The results suggest that both formyl peptide receptors play an essential role in Aβ1-42-induced signal transduction in glial cells. The interaction with RAGE could explain the broad ligand spectrum of formyl peptide receptors and their important role for inflammation and the host defence against infections.

  6. Non-enzymatic glucose detection using magnetic nanoemulsions

    International Nuclear Information System (INIS)

    Mahendran, V.; Philip, John

    2014-01-01

    We probe the optical properties and intermolecular interactions in magnetically responsive nanoemulsions in the presence of glucose. The equilibrium interdroplet distance between the emulsion droplets in an one-dimensional array increases by several nanometers in the presence of glucose because of intermolecular hydrogen bonding with sodium dodecyl sulphate molecules at the oil-water interface that gives rise to stretched lamellae-like structure. The observed large red shift in the diffracted Bragg peak (∼50–100 nm) and the linear response in the glucose concentration range of 0.25–25 mM offer a simple, fast, and cost effective non-enzymatic approach for glucose detection.

  7. Non-enzymatic palladium recovery on microbial and synthetic surfaces.

    Science.gov (United States)

    Rotaru, Amelia-Elena; Jiang, Wei; Finster, Kai; Skrydstrup, Troels; Meyer, Rikke Louise

    2012-08-01

    The use of microorganisms as support for reduction of dissolved Pd(II) to immobilized Pd(0) nanoparticles is an environmentally friendly approach for Pd recovery from waste. To better understand and engineer Pd(0) nanoparticle synthesis, one has to consider the mechanisms by which Pd(II) is reduced on microbial surfaces. Escherichia coli, Shewanella oneidensis, and Pseudomonas putida were used as model organisms in order to elucidate the role of microbial cells in Pd(II) reduction under acidic conditions. Pd(II) was reduced by formate under acidic conditions, and the process occurred substantially faster in the presence of cells as compared to cell-free controls. We found no difference between native (untreated) and autoclaved cells, and could demonstrate that even a non-enzymatic protein (bovine serum albumin) stimulated Pd(II) reduction as efficiently as bacterial cells. Amine groups readily interact with Pd(II), and to specifically test their role in surface-assisted Pd(II) reduction by formate, we replaced bacterial cells with polystyrene microparticles functionalized with amine or carboxyl groups. Amine-functionalized microparticles had the same effect on Pd(II) reduction as bacterial cells, and the effect could be hampered if the amine groups were blocked by acetylation. The interaction with amine groups was confirmed by infrared spectroscopy on whole cells and amine-functionalized microparticles. In conclusion, bio-supported Pd(II) reduction on microbial surfaces is possibly mediated by a non-enzymatic mechanism. We therefore suggest the use of amine-rich biomaterials rather than intact cells for Pd bio-recovery from waste. Copyright © 2012 Wiley Periodicals, Inc.

  8. Glucagon-Like Peptide-1 Secreting Cell Function as well as Production of Inflammatory Reactive Oxygen Species Is Differently Regulated by Glycated Serum and High Levels of Glucose

    Directory of Open Access Journals (Sweden)

    Alessandra Puddu

    2014-01-01

    Full Text Available Glucagon-like peptide-1 (GLP-1, an intestinal hormone contributing to glucose homeostasis, is synthesized by proglucagon and secreted from intestinal neuroendocrine cells in response to nutrients. GLP-1 secretion is impaired in type 2 diabetes patients. Here, we aimed at investigating whether diabetic toxic products (glycated serum (GS or high levels of glucose (HG may affect viability, function, and insulin sensitivity of the GLP-1 secreting cell line GLUTag. Cells were cultured for 5 days in presence or absence of different dilutions of GS or HG. GS and HG (alone or in combination increased reactive oxygen species (ROS production and upregulated proglucagon mRNA expression as compared to control medium. Only HG increased total production and release of active GLP-1, while GS alone abrogated secretion of active GLP-1. HG-mediated effects were associated with the increased cell content of the prohormone convertase 1/3 (PC 1/3, while GS alone downregulated this enzyme. HG upregulated Glucokinase (GK and downregulated SYNTHAXIN-1. GS abrogated SYNTHAXIN-1 and SNAP-25. Finally, high doses of GS alone or in combination with HG reduced insulin-mediated IRS-1 phosphorylation. In conclusion, we showed that GS and HG might regulate different pathways of GLP-1 production in diabetes, directly altering the function of neuroendocrine cells secreting this hormone.

  9. Advanced glycation end-products (AGES) and heart failure : Pathophysiology and clinical implications

    NARCIS (Netherlands)

    Hartog, Jasper W. L.; Voors, Adriaan A.; Bakker, Stephan J. L.; Smit, Andries J.; van Veldhuisen, Dirk J.

    2007-01-01

    Advanced glycation end-products (AGEs) are molecules formed during a non-enzymatic reaction between proteins and sugar residues, called the Maillard reaction. AGEs accumulate in the human body with age, and accumulation is accelerated in the presence of diabetes mellitus. In patients with diabetes,

  10. Preserving brain function in aging: The anti-glycative potential of berry fruit

    Science.gov (United States)

    Advanced glycation end-products (AGEs) are naturally occurring macromolecules that are formed in vivo by the non-enzymatic modification of proteins, lipids, or nucleic acids by sugar, even in the absence of hyperglycemia. In the diet, AGEs are found in animal products, and additional AGEs are produc...

  11. On the Growth Rate of Non-Enzymatic Molecular Replicators

    Directory of Open Access Journals (Sweden)

    Harold Fellermann

    2011-10-01

    Full Text Available It is well known that non-enzymatic template directed molecular replicators X + nO -> 2X exhibit parabolic growth d[X]/dt -> k[X]1/2. Here, we analyze the dependence of the effective replication rate constant k on hybridization energies, temperature, strand length, and sequence composition. First we derive analytical criteria for the replication rate k based on simple thermodynamic arguments. Second we present a Brownian dynamics model for oligonucleotides that allows us to simulate their diffusion and hybridization behavior. The simulation is used to generate and analyze the effect of strand length, temperature, and to some extent sequence composition, on the hybridization rates and the resulting optimal overall rate constant k. Combining the two approaches allows us to semi-analytically depict a replication rate landscape for template directed replicators. The results indicate a clear replication advantage for longer strands at lower temperatures in the regime where the ligation rate is rate limiting. Further the results indicate the existence of an optimal replication rate at the boundary between the two regimes where the ligation rate and the dehybridization rates are rate limiting.

  12. Non-enzymatic U(VI) interactions with biogenic mackinawite

    Science.gov (United States)

    Veeramani, H.; Qafoku, N. P.; Kukkadapu, R. K.; Murayama, M.; Hochella, M. F.

    2011-12-01

    Reductive immobilization of hexavalent uranium [U(VI)] by stimulation of dissimilatory metal and/or sulfate reducing bacteria (DMRB or DSRB) has been extensively researched as a remediation strategy for subsurface U(VI) contamination. These bacteria derive energy by reducing oxidized metals as terminal electron acceptors, often utilizing organic substrates as electron donors. Thus, when evaluating the potential for in-situ uranium remediation in heterogeneous subsurface media, it is important to understand how the presence of alternative electron acceptors such as Fe(III) and sulfate affect U(VI) remediation and the long term behavior and reactivity of reduced uranium. Iron, an abundant subsurface element, represents a substantial sink for electrons from DMRB, and the reduction of Fe(III) leads to the formation of dissolved Fe(II) or to reactive biogenic Fe(II)- and mixed Fe(II)/Fe(III)- mineral phases. Consequently, abiotic U(VI) reduction by reactive forms of biogenic Fe(II) minerals could be a potentially important process for uranium immobilization. In our study, the DMRB Shewanella putrefaciens CN32 was used to synthesize a biogenic Fe(II)-bearing sulfide mineral: mackinawite, that has been characterized by XRD, SEM, HRTEM and Mössbauer spectroscopy. Batch experiments involving treated biogenic mackinawite and uranium (50:1 molar ratio) were carried out at room temperature under strict anoxic conditions. Following complete removal of uranium from solution, the biogenic mackinawite was analyzed by a suite of analytical techniques including XAS, HRTEM and Mössbauer spectroscopy to determine the speciation of uranium and investigate concomitant Fe(II)-phase transformation. Determining the speciation of uranium is critical to success of a remediation strategy. The present work elucidates non-enzymatic/abiotic molecular scale redox interactions between biogenic mackinawite and uranium.

  13. Protein glycation during aging and in cardiovascular disease.

    Science.gov (United States)

    Simm, Andreas

    2013-10-30

    Advanced glycation endproducts (AGEs), pathophysiological important posttranslational modifications, are formed in vivo by a non-enzymatic reaction of proteins with reactive carbohydrates and accumulate during aging. They are discussed to be responsible for degenerative diseases. Glycation modifies the structure and function of proteins, induces tissue stiffening via crosslinking and a long-lasting inflammatory response after binding to AGE-receptors. Beside the extracellular matrix, a couple of intracellular proteins are known to be glycated leading to molecular and cellular dysfunction. In the cardiovascular system, AGEs are a major cause of cardiac and vascular dysfunction. Whereas AGEs are discussed to be potential biomarkers for diseases as well as for aging, the molecular analysis of AGEs in body fluids and tissue has still to be further improved. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Alteration of human serum albumin tertiary structure induced by glycation. Spectroscopic study.

    Science.gov (United States)

    Szkudlarek, A; Maciążek-Jurczyk, M; Chudzik, M; Równicka-Zubik, J; Sułkowska, A

    2016-01-15

    The modification of human serum albumin (HSA) structure by non-enzymatic glycation is one of the underlying factors that contribute to the development of complications of diabetes and neurodegenerative diseases. The aim of the present work was to estimate how glycation of HSA altered its tertiary structure. Changes of albumin conformation were investigated by comparison of glycated (gHSA) and non-glycated human serum albumin (HSA) absorption spectra, red edge excitation shift (REES) and synchronous spectra. Effect of glycation on human serum albumin tertiary structure was also investigated by (1)H NMR spectroscopy. Formation of gHSA Advanced Glycation End-products (AGEs) caused absorption of UV-VIS light between 310 nm and 400 nm while for non-glycated HSA in this region no absorbance has been registered. Analysis of red edge excitation shift effect allowed for observation of structural changes of gHSA in the hydrophobic pocket containing the tryptophanyl residue. Moreover changes in the microenvironment of tryptophanyl and tyrosyl residues brought about AGEs on the basis of synchronous fluorescence spectroscopy have been confirmed. The influence of glycation process on serum albumin binding to 5-dimethylaminonaphthalene-1-sulfonamide (DNSA), 2-(p-toluidino) naphthalene-6-sulfonic acid (TNS), has been studied. Fluorescence analysis showed that environment of both binding site I and II is modified by galactose glycation. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Selective detection of carbohydrates and their peptide conjugates by ESI-MS using synthetic quaternary ammonium salt derivatives of phenylboronic acids.

    Science.gov (United States)

    Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew

    2014-06-01

    We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation.

  16. Selective Detection of Carbohydrates and Their Peptide Conjugates by ESI-MS Using Synthetic Quaternary Ammonium Salt Derivatives of Phenylboronic Acids

    Science.gov (United States)

    Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew

    2014-06-01

    We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation.

  17. Advanced Glycation End Products: Link between Diet and Ovulatory Dysfunction in PCOS?

    OpenAIRE

    Garg, Deepika; Merhi, Zaher

    2015-01-01

    PCOS is the most common cause of anovulation in reproductive-aged women with 70% experiencing ovulatory problems. Advanced glycation end products are highly reactive molecules that are formed by non-enzymatic reactions of sugars with proteins, nucleic acids and lipids. AGEs are also present in a variety of diet where substantial increase in AGEs can result due to thermal processing and modifications of food. Elevation in bodily AGEs, produced endogenously or absorbed exogenously from high-AGE...

  18. Exploring the antioxidant property of bioflavonoid quercetin in preventing DNA glycation: A calorimetric and spectroscopic study

    International Nuclear Information System (INIS)

    Sengupta, Bidisa; Uematsu, Takashi; Jacobsson, Per; Swenson, Jan

    2006-01-01

    Reducing sugars for example glucose, fructose, etc., and their phosphate derivatives non-enzymatically glycate biological macromolecules (e.g., proteins, DNA and lipids) and is related to the production of free radicals. Here we present a novel study, using differential scanning calorimetry (DSC) along with UV/Vis absorption and photon correlation spectroscopy (PCS), on normal and glycated human placenta DNA and have explored the antioxidant property of the naturally occurring polyhydroxy flavone quercetin (3,3',4',5,7-pentahydroxyflavone) in preventing the glycation. The decrease in the absorption intensity of DNA in presence of sugars clearly indicates the existence of sugar molecules between the two bases of a base pair in the duplex DNA molecule. Variations were perceptible in the PCS relaxation profiles of normal and glycated DNA. The melting temperature of placenta DNA was decreased when glycated suggesting a decrease in the structural stability of the double-stranded glycated DNA. Our DSC and PCS data showed, for the first time, that the dramatic changes in the structural properties of glycated DNA can be prevented to a significant extent by adding quercetin. This study provides valuable insights regarding the structure, function, and dynamics of normal and glycated DNA molecules, underlying the manifestation of free radical mediated diseases, and their prevention using therapeutically active naturally occurring flavonoid quercetin

  19. Ketone Body Acetoacetate Buffers Methylglyoxal via a Non-enzymatic Conversion during Diabetic and Dietary Ketosis

    DEFF Research Database (Denmark)

    Salomon, Trine; Sibbersen, Christian; Hansen, Jakob

    2017-01-01

    now demonstrate that during ketosis, another meta- bolic route is operative via direct non-enzymatic aldol reaction between methylglyoxal and the ke- tone body acetoacetate, leading to 3-hydroxyhex- ane-2,5-dione. This novel metabolite is present at a concentration of 10%–20% of the methylglyoxal...

  20. Non-enzymatic depolymerization of cotton cellulose by fungal mimicking metabolites

    Science.gov (United States)

    Anne Christine Steenkjaer Hastrup; Caitlin Howell; Bo Jensen; Frederick Green

    2011-01-01

    Small, low molecular weight, non-enzymatic compounds have been linked to the early stages of brown rot decay as the enzymes involved with holocellulose degradation are too large to penetrate the S3 layer of intact wood cells. We investigated the most notable of these compounds, i.e. hydrogen peroxide, iron, and oxalic acid. The former two are involved in the Fenton...

  1. Non-enzymatic translocation in ribosomes from streptomycin-resistant mutants of Escherichia coli.

    Science.gov (United States)

    Asatryan, L S; Spirin, A S

    1975-07-10

    The capablity of ribosomes of four types of streptomycin-resistant mutants (A1, A2, A40 and A60) for non-enzymatic (EF-G--GTP-independent) translocation was tested. It was found that an A40 type mutation (amino acid replacement in position 87 of the protein S12 polypeptide chain) leads to activation of the capablity of the ribosome to perform spontaneous non-enzymatic translocation, while type A1, A2 and A60 mutations (amino acid replacements in position 42 of protein S12) does not give such an effect. Thus, it is shown that non-enzymatic translocation can be activated not only by the earlier described damage of the protein S12 by para-chloromercuribenzoate or by the complete removal of protein S12, but also by a definate mutational alteration of the protein. Preliminary data are also reported on the possibility of activating non-enzymatic translocation by combinations of mutational alterations of the ribosomal proteins other than protein S12 but interdepending with it (such as S4 and S5).

  2. The non-enzymatic inactivation of thirteen beta-lactam antibiotics in human faeces

    NARCIS (Netherlands)

    Jansen, G; Weissing, F; de Vries-Hospers, H; Tonk, R; van der Waaij, D

    1992-01-01

    In order to obtain a method that could predict the in vitro inactivation of an antibiotic in the digestive tract, the non-enzymatic inactivation of 13 beta-lactam antibiotics by human faeces was investigated. Benzylpenicillin, amoxicillin, amoxicillin/clavulanate, cloxacillin, piperacillin,

  3. The non-enzymatic inactivation of thirteen β-lactam antibiotics in human faeces

    NARCIS (Netherlands)

    Jansen, G; Weissing, F; de Vries Hospers, H; Tonk, R; van der Waaij, D

    1992-01-01

    In order to obtain a method that could predict the in vitro inactivation of an antibiotic in the digestive tract, the non-enzymatic inactivation of 13 beta-lactam antibiotics by human faeces was investigated. Benzylpenicillin, amoxicillin, amoxicillin/clavulanate, cloxacillin, piperacillin,

  4. Non-enzymatic modifications of prostaglandin H synthase 1 affect bifunctional enzyme activity - Implications for the sensitivity of blood platelets to acetylsalicylic acid.

    Science.gov (United States)

    Kassassir, Hassan; Siewiera, Karolina; Talar, Marcin; Stec-Martyna, Emilia; Pawlowska, Zofia; Watala, Cezary

    2016-06-25

    Due to its ability to inhibit the blood platelet PGHS-1, acetylsalicylic acid (ASA, Aspirin(®)) is widely used as a preventive agent in atherothrombotic diseases. However, its beneficial effects seem to be lower in diabetic patients, suggesting that protein glycation may impair effective ASA-mediated acetylation process. On the other hand, it is proposed that ASA can prevent some of the late complications of diabetes by lowering the extent of glycation at protein free amino groups. The aim of this work was to evaluate the extents of non-enzymatic N-glycosylation (glycation) and acetylation of blood platelet PGHS-1 (COX-1) and the competition between glycation and acetylation was investigated in order to demonstrate how these two reactions may compete against platelet PGHS-1. When PGHS-1 was incubated with glycating/acetylating agents (glucose, Glu; 1,6-bisphosphofructose, 1,6-BPF; methylglyoxal, MGO, acetylsalicylic acid, ASA), the enzyme was modified in 13.4 ± 1.6, 5.3 ± 0.5, 10.7 ± 1.2 and 6.4 ± 1.1 mol/mol protein, respectively, and its activity was significantly reduced. The prior glycation/carbonylation of PGHS-1 with Glu, 1,6-BPF or MGO decreased the extent of acetylation from 6.4 ± 1.1 down to 2.5 ± 0.2, 3.6 ± 0.3 and 5.2 ± 0.2 mol/mol protein, respectively, but the enzyme still remained susceptible to the subsequent inhibition of its activity with ASA. When PGHS-1 was first acetylated with ASA and then incubated with glycating/carbonylating agents, we observed the following reductions in the enzyme modifications: from 13.4 ± 1.6 to 8.7 ± 0.6 mol/mol protein for Glu, from 5.3 ± 0.5 to 3.9 ± 0.3 mol/mol protein for 1,6-BPF and from 10.7 ± 1.2 to 7.5 ± 0.5 mol/mol protein for MGO, however subsequent glycation/carbonylation did not significantly affect PGHS-1 function. Overall, our outcomes allow to better understand the structural aspects of the chemical competition between glycation and acetylation of PGHS-1

  5. Glycated hemoglobin is not an accurate indicator of glycemia in rainbow trout.

    Science.gov (United States)

    Santin, A E; Searle, A J; Winston, V D; Powell, M S; Hardy, R W; Rodnick, K J

    2013-07-01

    Glycation occurs when glucose reacts non-enzymatically with proteins. This reaction depends upon time, ambient glucose concentration, and the molecular conformation of reactive amino acids. Little is known about protein glycation in fishes and the main objective of this study was to measure glycated hemoglobin (GHb) in rainbow trout, a glucose-intolerant species, under normoglycemic and hyperglycemic conditions. We also identified GHb isoforms in vivo and analyzed the structural environment surrounding potential glycation sites. Despite similar glycemia to healthy humans, GHb was an order of magnitude lower in rainbow trout (0.6%) compared with humans (6%) and was not affected by long-term hyperglycemia. Species differences in GHb appear to be related to differences in erythrocyte glucose, and differential expression and glycation of hemoglobin (Hb) isoforms may explain intraspecific differences in rainbow trout GHb. Computer analysis of glucose isomers (ringed-open and α- and β-pyranoses) interacting with the β-chain of rainbow trout HbI and HbIV, and human HbA did not reveal structural or energetic constraints for glucose binding (the initial step of glycation) for rainbow trout Hbs. Overall, there are significant differences between Hb glycation in humans and rainbow trout, and GHb does not appear to be an accurate indicator of glycemia over time in rainbow trout. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. The Effect of Irradiation Treatment on the Non-Enzymatic Browning Reaction in Legume Seeds

    International Nuclear Information System (INIS)

    El-Niely, H.F.G.

    2013-01-01

    The present study was conducted to evaluate the effects of gamma irradiation treatment, at room temperature, on the non-enzymatic browning reaction (Millerd reaction products, MRPs) generated in soybeans, broad beans and dried peas seeds at dose levels of 10, 30 and 60 kGy and their effects on the chemical constituents, soluble protein, available lysine and in vitro protein digestibility. The formation of MRPs in the studied legumes was assayed by monitoring the formation of brown pigments (browning intensity) by spectrophotometric method. The results revealed that the chemical composition of irradiated legumes showed non-significant differences relative to the raw one. A dose dependent decrease in soluble proteins and available lysine in the three legumes were observed. The non-enzymatic browning reaction was significantly increased with increasing the radiation dose, which was proved by changes in browning index tests. At the same time, the in vitro protein digestibility was increased after irradiation up to 60 kGy. Irradiation of dried peas with 60 kGy produced higher browning index than the other legumes. A positive correlation was observed between the radiation dose and the browning index for soybeans (R2= 0.96), broad beans (R2 = 0.81) and dried peas (R2 = 0.97) which means that 96%, 81% and 97 of the variation in the incidence of non-enzymatic browning reaction in soybean, broad bean and dried peas, respectively, are due to the effect of irradiation treatments. The present study suggests that the formation of non-enzymatic browning reaction did not impair the nutritional quality of legumes, therefore, the process of irradiation was helpful in increasing the in vitro protein digestibility of studied legumes. These results clearly indicated that gamma irradiation processing at the studied doses can add valuable effects to the studied legumes

  7. Fabrication of Nickel/nanodiamond/boron-doped diamond electrode for non-enzymatic glucose biosensor

    International Nuclear Information System (INIS)

    Dai, Wei; Li, Mingji; Gao, Sumei; Li, Hongji; Li, Cuiping; Xu, Sheng; Wu, Xiaoguo; Yang, Baohe

    2016-01-01

    Highlights: • Nanodiamonds (NDs) were electrophoretically deposited on the BDD film. • The NDs significantly extended the potential window. • Ni/NDs/BDD electrode was prepared by electrodeposition. • The electrode shows good catalytic activity for glucose oxidation. - Abstract: A stable and sensitive non-enzymatic glucose sensor was prepared by modifying a boron-doped diamond (BDD) electrode with nickel (Ni) nanosheets and nanodiamonds (NDs). The NDs were electrophoretically deposited on the BDD surface, and acted as nucleation sites for the subsequent electrodeposition of Ni. The morphology and composition of the modified BDD electrodes were characterized by field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The Ni nanosheet-ND modified BDD electrode exhibited good current response towards the non-enzymatic oxidation of glucose in alkaline media. The NDs significantly extended the potential window. The response to glucose was linear over the 0.2–1055.4-μM range. The limit of detection was 0.05 μM, at a signal-to-noise ratio of 3. The Ni nanosheet-ND/BDD electrode exhibited good selectivity, reproducibility and stability. Its electrochemical performance, low cost and simple preparation make it a promising non-enzymatic glucose sensor.

  8. Non-enzymatic N-acetylation of Lysine Residues by AcetylCoA Often Occurs via a Proximal S-acetylated Thiol Intermediate Sensitive to Glyoxalase II

    Directory of Open Access Journals (Sweden)

    Andrew M. James

    2017-02-01

    Full Text Available Summary: Acetyl coenzyme A (AcCoA, a key intermediate in mitochondrial metabolism, N-acetylates lysine residues, disrupting and, in some cases, regulating protein function. The mitochondrial lysine deacetylase Sirtuin 3 (Sirt3 reverses this modification with benefits reported in diabetes, obesity, and aging. We show that non-enzymatic lysine N-acetylation by AcCoA is greatly enhanced by initial acetylation of a cysteine residue, followed by SN-transfer of the acetyl moiety to a nearby lysine on mitochondrial proteins and synthetic peptides. The frequent occurrence of an S-acetyl intermediate before lysine N-acetylation suggests that proximity to a thioester is a key determinant of lysine susceptibility to acetylation. The thioesterase glyoxalase II (Glo2 can limit protein S-acetylation, thereby preventing subsequent lysine N-acetylation. This suggests that the hitherto obscure role of Glo2 in mitochondria is to act upstream of Sirt3 in minimizing protein N-acetylation, thus limiting protein dysfunction when AcCoA accumulates. : James et al. show that the non-enzymatic N-acetylation of lysine residues in mitochondrial proteins frequently occurs via a proximal S-acetylated thiol intermediate. Glutathione equilibrates with this intermediate, allowing the thioesterase glyoxalase II to limit protein lysine N-acetylation. These findings expand our understanding of how protein acetylation arises. Keywords: AcetylCoA, lysine acetylation, glyoxalase

  9. Preclinical pharmacokinetic, biodistribution, imaging and therapeutic efficacy of 177Lu-Labeled glycated bombesin analogue for gastrin-releasing peptide receptor-positive prostate tumor targeting

    International Nuclear Information System (INIS)

    Lim, Jae Cheong; Cho, Eun Ha; Kim, Jin Joo; Choi, Sang Mu; Lee, So Young; Nam, Sung Soo; Park, Ul Jae; Park, Soo Hyun

    2015-01-01

    The gastrin-releasing peptide receptor (GRPR) has been shown to be overexpressed in many human tumors, including prostate, colon, gastric, breast, pancreatic, and small cell lung cancers. Because bombesin (BBS) binds to GRPR with high affinity, BBS derivatives have been labeled with various radionuclides and have been demonstrated to be successful candidates for peptide receptor radiotherapy (PRRT). The present study describes the in vitro and in vivo preclinical characteristics of 177 Lu-DOTA-Lys(glucose)-4 aminobenzoic acid-BBS 7-14 ( 177 Lu-DOTA-gluBBN) to prepare radiolabeled candidates for the treatment of GRPR-expressing prostate tumors. Methods: 177 Lu-DOTA-gluBBN was prepared as previously published [1]. Human prostate PC-3 tumor cells were used to determine the binding (Kd) retention and efflux of 177 Lu-DOTA-gluBBN. Pharmacokinetic, imaging, and radiotherapy studies were performed in PC-3 xenografted mice. Results: The Kd value of 177 Lu-DOTA-gluBBN was 0.63 nM, with a maximum binding capacity (Bmax) of 669.7 fmol/10 6 cells (4.04 × 10 5 GRPR/cell). During a 2-hr incubation, 90.1 ± 0.4% of the cell-associated radio-peptide was internalized, and 56.3 ± 7.1% of the internalized radio-peptide was externalized in vitro. High amounts of the radio-peptide were rapidly accumulated in a PC-3 tumor in vivo, and the % ID/g of the tumor was 12.42 ± 2.15 1 hr p.i. The radio-peptide was quickly cleared from the blood, yielding tumor-to-blood ratios of 39.22 ± 17.36 at 1 hr p.i. and 330.67 ± 131.23 at 24 hr p.i. In addition, 177 Lu-DOTA-gluBBN was clearly visualized in PC-3 tumors 1 hr p.i. and significantly inhibited the tumor growth (P < 0.05). Treatment-related toxicity in the pancreas and kidneys was not observed, except for slight glomerulopathy. Conclusions: The pharmacokinetic, imaging, and therapy studies suggest that this 177 Lu-DOTA-gluBBN has promising characteristics for application in nuclear medicine, namely, for the diagnosis and treatment of GRPR

  10. Using Serum Advanced Glycation End Products-Peptides to Improve the Efficacy of World Health Organization Fasting Plasma Glucose Criterion in Screening for Diabetes in High-Risk Chinese Subjects.

    Science.gov (United States)

    Sun, Zilin; He, Jiajia; Qiu, Shanhu; Lei, Chenghao; Zhou, Yi; Xie, Zuolin; Zhang, Lin; Wang, Yanping; Jin, Hui

    2015-01-01

    The efficacy of using fasting plasma glucose (FPG) alone as a preferred screening test for diabetes has been questioned. This study was aimed to evaluate whether the use of serum advanced glycation end products-peptides (sAGEP) would help to improve the efficacy of FPG in diabetes screening among high-risk Chinese subjects with FPG World Health Organization FPG criterion (FPG ≥7.0 mmol/L). The area under ROC curves generated by the model on FPG-sAGEP was the largest compared with that on FPG-HbA1c, sAGEP, HbA1c or FPG in subjects with FPG <7.0 mmol/L. By maximizing the sum of sensitivity and specificity, the optimal critical line was determined as 0.69×FPG + 0.14×sAGEP = 7.03, giving a critical sensitivity of 91.2% in detecting 2h-PG ≥11.1 mmol/L, which was significantly higher than that of FPG-HbA1c or HbA1c. The model on FPG-sAGEP improves the efficacy of using FPG alone in detecting diabetes among high-risk Chinese subjects with FPG <7.0 mmol/L, and is worth being promoted for future diabetes screening.

  11. Protective effect of Withania somnifera (Solanaceae) on collagen glycation and cross-linking.

    Science.gov (United States)

    Babu, Pon Velayutham Anandh; Gokulakrishnan, Adikesavan; Dhandayuthabani, Rajendra; Ameethkhan, Dowlath; Kumar, Chandrasekara Vimal Pradeep; Ahamed, Md Iqbal Niyas

    2007-06-01

    Modification of collagen such as non-enzymatic glycation and cross-linking plays an important role in diabetic complications and age-related diseases. We evaluate the effect of Withania somnifera on glucose-mediated collagen glycation and cross-linking in vitro. Extent of glycation, viscosity, collagen-linked fluorescence and pepsin solubility were assessed in different experimental procedures to investigate the effect of W. somnifera. Tail tendons obtained from rats (Rattus norvegicus) weighing 250-275 g were incubated with 50 mM glucose and 100 mg of metformin or Withania root powder or ethanolic extract of Withania under physiological conditions of temperature and pH for 30 days. Formation of advanced glycation end products (AGE) was measured by fluorescent method whereas the cross-linking of collagen was assessed by pepsin digestion and viscosity measurements. Tendon collagen incubated with glucose showed an increase in glycation, AGE and cross-linking of collagen. The collagen incubated with W. somnifera and metformin ameliorates these modifications. The ethanolic extract of Withania showed more prominent effect than Withania root powder. The activity of ethanolic extract of Withania is comparable to metformin, a known antiglycating agent. In conclusion, Withania could have therapeutic role in the prevention of glycation induced pathogenesis in diabetes mellitus and aging.

  12. Using Serum Advanced Glycation End Products-Peptides to Improve the Efficacy of World Health Organization Fasting Plasma Glucose Criterion in Screening for Diabetes in High-Risk Chinese Subjects.

    Directory of Open Access Journals (Sweden)

    Zilin Sun

    Full Text Available The efficacy of using fasting plasma glucose (FPG alone as a preferred screening test for diabetes has been questioned. This study was aimed to evaluate whether the use of serum advanced glycation end products-peptides (sAGEP would help to improve the efficacy of FPG in diabetes screening among high-risk Chinese subjects with FPG <7.0 mmol/L. FPG, 2-h plasma glucose (2h-PG, serum glycated haemoglobin A1c (HbA1c, and sAGEP were measured in 857 Chinese subjects with risk factors for diabetes. The areas under receiver operating characteristic (ROC curves generated by logistic regression models were assessed and compared to find the best model for diabetes screening in subjects with FPG <7.0 mmol/L. The optimal critical line was determined by maximizing the sum of sensitivity and specificity. Among the enrolled subjects, 730 of them had FPG <7.0 mmol/L, and only 41.7% new diabetes cases were identified using the 1999 World Health Organization FPG criterion (FPG ≥7.0 mmol/L. The area under ROC curves generated by the model on FPG-sAGEP was the largest compared with that on FPG-HbA1c, sAGEP, HbA1c or FPG in subjects with FPG <7.0 mmol/L. By maximizing the sum of sensitivity and specificity, the optimal critical line was determined as 0.69×FPG + 0.14×sAGEP = 7.03, giving a critical sensitivity of 91.2% in detecting 2h-PG ≥11.1 mmol/L, which was significantly higher than that of FPG-HbA1c or HbA1c. The model on FPG-sAGEP improves the efficacy of using FPG alone in detecting diabetes among high-risk Chinese subjects with FPG <7.0 mmol/L, and is worth being promoted for future diabetes screening.

  13. Highly ordered Ni–Ti–O nanotubes for non-enzymatic glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Hang, Ruiqiang, E-mail: hangruiqiang@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Yanlian [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Gao, Ang [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Bai, Long; Huang, Xiaobo; Zhang, Xiangyu; Lin, Naiming [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Tang, Bin, E-mail: tangbin@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2015-06-01

    Anodization is used to fabricate Ni–Ti–O nanotube (NT) electrodes for non-enzymatic glucose detection. The morphology, microstructure and composition of the materials are characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Our results show amorphous and highly ordered NTs with diameter of 50 nm, length of 800 nm, and Ni/Ti ratio (at %) of 0.35 can be fabricated in ethylene glycol electrolyte supplemented with 0.2 wt.% NH{sub 4}F and 0.5 vol.% H{sub 2}O at 30 °C and 25 V for 1 h. Electrochemical experiments indicate that at an applied potential of 0.60 V vs. Ag/AgCl, the electrode exhibits a linear response window for glucose concentrations from 0.002 mM to 0.2 mM with a response time of 10 s, detection limit of 0.13 μM (S/N = 3), and sensitivity of 83 μA mM{sup −1} cm{sup −2}. The excellent performance of the electrode is attributed to its large specific area and fast electron transfer between the NT walls. The good electrochemical performance of the Ni–Ti–O NTs as well as their simple and low-cost preparation method make the strategy promising in non-enzymatic glucose detection. - Highlights: • Highly ordered Ni–Ti–O nanotubes have been fabricated by one-step anodization. • We find H{sub 2}O contents in the electrolyte is critical to successful fabrication of the NTs. • The Ni–Ti–O nanotubes are ideal electrode materials for non-enzymatic glucose detection.

  14. Dietary advanced glycation end products and aging.

    Science.gov (United States)

    Luevano-Contreras, Claudia; Chapman-Novakofski, Karen

    2010-12-01

    Advanced glycation end products (AGEs) are a heterogeneous, complex group of compounds that are formed when reducing sugar reacts in a non-enzymatic way with amino acids in proteins and other macromolecules. This occurs both exogenously (in food) and endogenously (in humans) with greater concentrations found in older adults. While higher AGEs occur in both healthy older adults and those with chronic diseases, research is progressing to both quantify AGEs in food and in people, and to identify mechanisms that would explain why some human tissues are damaged, and others are not. In the last twenty years, there has been increased evidence that AGEs could be implicated in the development of chronic degenerative diseases of aging, such as cardiovascular disease, Alzheimer's disease and with complications of diabetes mellitus. Results of several studies in animal models and humans show that the restriction of dietary AGEs has positive effects on wound healing, insulin resistance and cardiovascular diseases. Recently, the effect of restriction in AGEs intake has been reported to increase the lifespan in animal models. This paper will summarize the work that has been published for both food AGEs and in vivo AGEs and their relation with aging, as well as provide suggestions for future research.

  15. Dietary Advanced Glycation End Products and Aging

    Directory of Open Access Journals (Sweden)

    Karen Chapman-Novakofski

    2010-12-01

    Full Text Available Advanced glycation end products (AGEs are a heterogeneous, complex group of compounds that are formed when reducing sugar reacts in a non-enzymatic way with amino acids in proteins and other macromolecules. This occurs both exogenously (in food and endogenously (in humans with greater concentrations found in older adults. While higher AGEs occur in both healthy older adults and those with chronic diseases, research is progressing to both quantify AGEs in food and in people, and to identify mechanisms that would explain why some human tissues are damaged, and others are not. In the last twenty years, there has been increased evidence that AGEs could be implicated in the development of chronic degenerative diseases of aging, such as cardiovascular disease, Alzheimer’s disease and with complications of diabetes mellitus. Results of several studies in animal models and humans show that the restriction of dietary AGEs has positive effects on wound healing, insulin resistance and cardiovascular diseases. Recently, the effect of restriction in AGEs intake has been reported to increase the lifespan in animal models. This paper will summarize the work that has been published for both food AGEs and in vivo AGEs and their relation with aging, as well as provide suggestions for future research.

  16. Non-Enzymatic Glucose Sensor Composed of Carbon-Coated Nano-Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Ren-Jei Chung

    2017-02-01

    Full Text Available Nowadays glucose detection is of great importance in the fields of biological, environmental, and clinical analyzes. In this research, we report a zinc oxide (ZnO nanorod powder surface-coated with carbon material for non-enzymatic glucose sensor applications through a hydrothermal process and chemical vapor deposition method. A series of tests, including crystallinity analysis, microstructure observation, and electrochemical property investigations were carried out. For the cyclic voltammetric (CV glucose detection, the low detection limit of 1 mM with a linear range from 0.1 mM to 10 mM was attained. The sensitivity was 2.97 μA/cm2mM, which is the most optimized ever reported. With such good analytical performance from a simple process, it is believed that the nanocomposites composed of ZnO nanorod powder surface-coated with carbon material are promising for the development of cost-effective non-enzymatic electrochemical glucose biosensors with high sensitivity.

  17. A Highly Sensitive Electrochemical Glucose Sensor By Nickel-Epoxy Electrode With Non-Enzymatic Sensor

    Directory of Open Access Journals (Sweden)

    Riyanto Riyanto

    2016-03-01

    Full Text Available The preparation of new sensor for glucose was based on the fact that glucose can be determined by non-enzymatic glucose oxidase. The Ni metals (99.98% purity, 0.5 mm thick, Aldrich Chemical Company was used to prepare Ni-Epoxy electrode. The Ni-epoxy electrodes were prepared in square cut of 1 cm and 1 mm by length and wide respectively. The Ni metal electrodes were connected to silver wire with silver conducting paint prior covered with epoxy gum. The prepared of nickel-epoxy modified electrode showed outstanding electro catalytic activity toward the oxidation of glucose in alkaline solution. The result from this research are correlation of determination using Nickel-Epoxyelectrode for electroanalysis of glucose in NaOH was R2 = 0.9984. LOQ, LOD and recovery of the Nickel-Epoxy electrode towards glucose were found to be 4.4 μM, 1.48 μM and 98.19%, respectively. The Nickel-Epoxy wire based electrochemical glucose sensor demonstrates good sensitivity, wide linear range, outstanding detection limit, attractive selectivity, good reproducibility, high stability as well as prominent feasibility use of non-enzymatic sensor for monitoring glucose in human urine owing to its advantages of low cost, simple preparation and excellent properties for glucose detection.

  18. Facile synthesis of a silver nanoparticles/polypyrrole nanocomposite for non-enzymatic glucose determination.

    Science.gov (United States)

    Poletti Papi, Maurício A; Caetano, Fabio R; Bergamini, Márcio F; Marcolino-Junior, Luiz H

    2017-06-01

    The present work describes the synthesis of a new conductive nanocomposite based on polypyrrole (PPy) and silver nanoparticles (PPy-AgNP) based on a facile reverse microemulsion method and its application as a non-enzymatic electrochemical sensor for glucose detection. Focusing on the best sensor performance, all experimental parameters used in the synthesis of nanocomposite were optimized based on its electrochemical response for glucose. Characterization of the optimized material by FT-IR, cyclic voltammetry, and DRX measurements and TEM images showed good monodispersion of semispherical Ag nanoparticles capped by PPy structure, with size average of 12±5nm. Under the best analytical conditions, the proposed sensor exhibited glucose response in linear dynamic range of 25 to 2500μmolL -1 , with limit of detection of 3.6μmolL -1 . Recovery studies with human saliva samples varying from 99 to 105% revealed the accuracy and feasibility of a non-enzymatic electrochemical sensor for glucose determination by easy construction and low-cost. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Nitrogen-doped graphene-silver nanodendrites for the non-enzymatic detection of hydrogen peroxide

    International Nuclear Information System (INIS)

    Tajabadi, M.T.; Basirun, W.J.; Lorestani, F.; Zakaria, R.; Baradaran, S.; Amin, Y.M.; Mahmoudian, M.R.; Rezayi, M.; Sookhakian, M.

    2015-01-01

    Highlights: • N-graphene/Ag nanodendrities by electrophoretic and electrochemical deposition. • Support of N-graphene shows efficient electrocatalytic activity toward H 2 O 2 reduction. • The fabricated non-enzymatic H 2 O 2 electrochemical sensor improved in the presence of Ag. - Abstract: An organic-metal hybrid film based on nitrogen-doped graphene-silver nanodendrites (Ag-NG) was fabricated on an indium tin oxide (ITO) electrode using a simple electrophoretic and electrochemical sequential deposition approach. The microwave-assisted method was utilized for the synthesis of nitrogen-doped graphene. This method involves a three-step process consisting of graphite oxidation, exfoliation, and finally chemical reduction with the use of hydrazine as the reducing agent, which leads to the simultaneous reduction of graphene oxide and production of nitrogen-doped graphene. The morphology and structure of the as-fabricated electrode were determined by X-ray diffraction, field emission electron microscopy and transmission electron microscopy. The as-prepared Ag-NG-modified ITO electrode exhibited superior electrocatalytic activity toward hydrogen peroxide (H 2 O 2 ) reduction, with a wide linear detection range of 100 μM to 80 mM (r = 0.9989) and a detection limit of 0.26 μM with a signal-to-noise ratio of 3. Furthermore, the fabricated non-enzymatic H 2 O 2 electrochemical sensor exhibited excellent stability and reproducibility

  20. Glucagon-like peptide-1 receptor agonist inhibits asymmetric dimethylarginine generation in the kidney of streptozotocin-induced diabetic rats by blocking advanced glycation end product-induced protein arginine methyltranferase-1 expression.

    Science.gov (United States)

    Ojima, Ayako; Ishibashi, Yuji; Matsui, Takanori; Maeda, Sayaka; Nishino, Yuri; Takeuchi, Masayoshi; Fukami, Kei; Yamagishi, Sho-ichi

    2013-01-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in diabetic nephropathy. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, contributes to diabetic nephropathy. We have found that glucagon-like peptide-1 (GLP-1) inhibits the AGE-induced inflammatory reactions in endothelial cells. However, effects of GLP-1 on the AGE-RAGE-ADMA axis are unknown. This study examined the effects of GLP-1 on reactive oxygen species (ROS) generation, gene expression of protein arginine methyltransfetase-1 (PRMT-1), an enzyme that mainly generates ADMA, and ADMA levels in human proximal tubular cells. Streptozotocin-induced diabetic rats received continuous i.p. infusion of 0.3 μg of vehicle or 1.5 μg of the GLP-1 analog exendin-4 per kilogram of body weight for 2 weeks. We further investigated whether and how exendin-4 treatment reduced ADMA levels and renal damage in streptozotocin-induced diabetic rats. GLP-1 inhibited the AGE-induced RAGE and PRMT-1 gene expression, ROS, and ADMA generation in tubular cells, which were blocked by small-interfering RNAs raised against GLP-1 receptor. Exendin-4 treatment decreased gene expression of Rage, Prmt-1, Icam-1, and Mcp-1 and ADMA level; reduced urinary excretions of 8-hydroxy-2'-deoxyguanosine and albumin; and improved histopathologic changes of the kidney in diabetic rats. Our present study suggests that GLP-1 receptor agonist may inhibit the AGE-RAGE-mediated ADMA generation by suppressing PRMT-1 expression via inhibition of ROS generation, thereby protecting against the development and progression of diabetic nephropathy. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  1. Hexose-derived glycation sites in processed bovine milk.

    Science.gov (United States)

    Milkovska-Stamenova, Sanja; Hoffmann, Ralf

    2016-02-16

    Milk products are consumed by many people on a daily basis, which demands sophisticated technical processes to guarantee the microbiological safety and to retain the nutritional value. The heating during pasteurization and ultra high temperature (UHT) treatment triggers diverse chemical reactions, such as the reaction of sugars and amino groups of proteins typically termed protein glycation. The glycation by lactose as dominant sugar in milk has been recently investigated, whereas the contribution of hexoses remains open. We identified first hexose-derived glycation sites in raw milk, colostrum, three brands of pasteurized milk, three brands of UHT milk, five brands of infant formula, and one brand of lactose-free pasteurized and UHT milk using tandem mass spectrometry and electron transfer dissociation. In total, we could identify 124 hexosylated tryptic peptides in a bottom-up proteomics approach after enriching glycated peptides by boronate affinity chromatography, which corresponded to 86 glycation sites in 17 bovine milk proteins. In quantitative terms glycation increased from raw milk to pasteurized milk to UHT milk and infant formula. Lactose-free milk contained significantly higher hexosylation degrees than the corresponding regular milk product. Interestingly, the glycation degrees varied considerably among different brands with lactose-free UHT milk and infant formula showing the highest levels. The established proteomics strategy enables the identification and relative quantification of different protein glycation types in diverse milk products ranging from raw milk to milk powders. This will allow detailed in vitro studies to judge positive or negative aspects when consuming differently processed milk products including lactose-free milk that is obligatory for people with lactose intolerance but is increasingly consumed by the general population assuming health benefits. The established analytics will also permit studying the influence of each technical

  2. Pathological Significance of Mitochondrial Glycation

    Directory of Open Access Journals (Sweden)

    Pamela Boon Li Pun

    2012-01-01

    Full Text Available Glycation, the nonenzymatic glycosylation of biomolecules, is commonly observed in diabetes and ageing. Reactive dicarbonyl species such as methylglyoxal and glyoxal are thought to be major physiological precursors of glycation. Because these dicarbonyls tend to be formed intracellularly, the levels of advanced glycation end products on cellular proteins are higher than on extracellular ones. The formation of glycation adducts within cells can have severe functional consequences such as inhibition of protein activity and promotion of DNA mutations. Although several lines of evidence suggest that there are specific mitochondrial targets of glycation, and mitochondrial dysfunction itself has been implicated in disease and ageing, it is unclear if glycation of biomolecules specifically within mitochondria induces dysfunction and contributes to disease pathology. We discuss here the possibility that mitochondrial glycation contributes to disease, focussing on diabetes, ageing, cancer, and neurodegeneration, and highlight the current limitations in our understanding of the pathological significance of mitochondrial glycation.

  3. Enzymatic and non-enzymatic detoxification of 4-hydroxynonenal: Methodological aspects and biological consequences.

    Science.gov (United States)

    Mol, Marco; Regazzoni, Luca; Altomare, Alessandra; Degani, Genny; Carini, Marina; Vistoli, Giulio; Aldini, Giancarlo

    2017-10-01

    4-Hydroxynonenal (HNE), an electrophilic end-product deriving from lipid peroxidation, undergoes a heterogeneous set of biotransformations including enzymatic and non-enzymatic reactions. The former mostly involve red-ox reactions on the HNE oxygenated functions (phase I metabolism) and GSH conjugations (phase II) while the latter are due to the HNE capacity to spontaneously condense with nucleophilic sites within endogenous molecules such as proteins, nucleic acids and phospholipids. The overall metabolic fate of HNE has recently attracted great interest not only because it clearly determines the HNE disposal, but especially because the generated metabolites and adducts are not inactive molecules (as initially believed) but show biological activities even more pronounced than those of the parent compound as exemplified by potent pro-inflammatory stimulus induced by GSH conjugates. Similarly, several studies revealed that the non-enzymatic reactions, initially considered as damaging processes randomly involving all endogenous nucleophilic reactants, are in fact quite selective in terms of both reactivity of the nucleophilic sites and stability of the generated adducts. Even though many formed adducts retain the expected toxic consequences, some adducts exhibit well-defined beneficial roles as documented by the protective effects of sublethal concentrations of HNE against toxic concentrations of HNE. Clearly, future investigations are required to gain a more detailed understanding of the metabolic fate of HNE as well as to identify novel targets involved in the biological activity of the HNE metabolites. These studies are and will be permitted by the continuous progress in the analytical methods for the identification and quantitation of novel HNE metabolites as well as for proteomic analyses able to offer a comprehensive picture of the HNE-induced adducted targets. On these grounds, the present review will focus on the major enzymatic and non-enzymatic HNE

  4. Anti-glycated and antiradical activities in vitro of polysaccharides from Ganoderma capense.

    Science.gov (United States)

    Yan, Chunyan; Kong, Fansheng; Zhang, Dezhi; Cui, Jiangxia

    2013-01-01

    Ganoderma capense is a Ganoderma species and is widely used, especially in Asia, as a well-known medicinal mushroom for health-promoting effect and for treatment of chronic diseases, such as diabetes, aging, etc. G. capense is rich of polysaccharide. To isolate the polysaccharides from G. capense and evaluate their anti-glycated and antiradical activities in vitro. The dried powder of submerged fermentation culturing mycelium of G. capense was defatted, extracted with water/alkaline water followed by ethanol precipitation and deproteinated. And four crude polysaccharides, named as GC50, GC70, GC90 and GCB, were obtained. For the first time, the in vitro anti-glycated activities of the four samples were studied by non-enzymatic glycation reaction. Then, the DPPH radical and hydroxyl radical assays were established to estimate the antiradical capacity of the four samples. Meanwhile the contents of polysaccharides were determined by phenol-sulphuric acid colorimetry. Preliminary antiradical in vitro studies indicated that the four crude polysaccharides showed concentration-dependent scavenging abilities on DPPH and hydroxyl radicals. The evaluation of anti-glycation activity suggested that GC70 had good potential for inhibiting the formation of advanced glycation end products. Time- and dose-dependent effects were also observed for all GC70 samples.

  5. Investigation of lipid oxidation and non-enzymatic browning reactions in marine PL emulsions

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Nielsen, Nina Skall; Baron, Caroline P.

    Marine phospholipids (PL) have received much attention recently due to their numerous advantages. One of these advantages is their better resistance towards oxidation as compared to fish oil. In addition to the antioxidative properties of α-tocopherol and phospholipids, the better oxidative...... stability of marine PL might be attributed to antioxidative properties of pyrroles formed between oxidised lipids with amine groups from phosphatidylethanolamine (PE) or residues amino acids that are present in marine PL. The main objective of this study was to investigate if the presence of amine group...... from PE or amino acids affected the oxidative stability of purified marine PL emulsions. The secondary objective was to study the non-enzymatic browning reactions in the emulsions which included both Strecker degradation (SD) and pyrroles formation. Emulsions were prepared with and without addition...

  6. High Performance Non-enzymatic Glucose Sensor Based on One-Step Electrodeposited Nickel Sulfide.

    Science.gov (United States)

    Kannan, Padmanathan Karthick; Rout, Chandra Sekhar

    2015-06-22

    Nanostructured NiS thin film was prepared by a one-step electrodeposition method and the structural, morphological characteristics of the as-prepared films were analyzed by X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDAX). The electrocatalytic activity of NiS thin film towards glucose oxidation was investigated by fabricating a non-enzymatic glucose sensor and the sensor performance was studied by cyclic voltammetry (CV) and amperometry. The fabricated sensor showed excellent sensitivity and low detection limit with values of 7.43 μA μM(-1)  cm(-2) and 0.32 μM, respectively, and a response time of <8 s. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Role of enzymatic and non enzymatic antioxidant in ameliorating salinity induced damage in nostoc muscorum

    International Nuclear Information System (INIS)

    Hend, A.; Abeer, A.; Allah, A.

    2015-01-01

    Presence of high salt concentration in the growth medium adversely affected the plant growth and productivity by altering its metabolic activities. Experiments were conducted on cyanobacteriaum Nostoc muscorum grown in nitrogen free medium supplemented with 250 mM NaCl to evaluate the salt stress induced changes in growth, antioxidants and lipid composition. Salt stress significantly reduced the growth and physio-biochemical attributes. Salt stress increased malonaldehyde content thereby causing alterations in the lipid fraction. Significant reduction in polyunsaturated fatty acids including phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI) and phosphatidylserine (PS) was observed. Where as diacylglycerol, sterol ester and non-esterified fatty acids were increased. Activities of antioxidant enzymes and contents of non-enzymatic antioxidants including glutathione enhanced due to salt stress. An increase in accumulation of proline was also observed. Hence increased activity of antioxidants and altered fatty acid composition was observed in salt stressed Nostoc muscorum. (author)

  8. Non-Enzymatic Glucose Biosensor Based on CuO-Decorated CeO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Panpan Guan

    2016-08-01

    Full Text Available Copper oxide (CuO-decorated cerium oxide (CeO2 nanoparticles were synthesized and used to detect glucose non-enzymatically. The morphological characteristics and structure of the nanoparticles were characterized through transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The sensor responses of electrodes to glucose were investigated via an electrochemical method. The CuO/CeO2 nanocomposite exhibited a reasonably good sensitivity of 2.77 μA mM−1cm−2, an estimated detection limit of 10 μA, and a good anti-interference ability. The sensor was also fairly stable under ambient conditions.

  9. The effect of irradiation temperature on the non-enzymatic browning reaction in cooked rice

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ju-Woon [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, PO Box 1266, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Oh, Sang-Hee [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, PO Box 1266, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Kim, Jae-Hun [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, PO Box 1266, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Byun, Eui-Hong [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, PO Box 1266, Jeongeup, Jeonbuk 580-185 (Korea, Republic of); Ree Kim, Mee [Department of Food and Nutrition, Chungnam National University, Gung-Dong 220, Yuseong, Daejeon 305-764 (Korea, Republic of); Baek, Min [Atomic Energy Policy Division, Ministry of Science and Technology, Government Complex-Gwacheon, Kyunggi 427-715 (Korea, Republic of); Byun, Myung-Woo [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, PO Box 1266, Jeongeup, Jeonbuk 580-185 (Korea, Republic of)]. E-mail: mwbyun@kaeri.re.kr

    2007-05-15

    The effect of irradiation temperature on the non-enzymatic browning reaction in a sugar-glycine solution and cooked rice generated by gamma irradiation was evaluated in the present study. When the sugar-glycine solution and cooked rice were irradiated at room temperature, the browning reaction was dramatically increased during the post-irradiation period. In the case of irradiation at below the freezing point, the browning by irradiation was retarded during not only irradiation but also a post-irradiation period. The changes of the sugar profile, such as a sugar loss or reducing power of the irradiated sugar-glycine solution and the electron spin resonance signal intensity of the irradiated cooked rice were also decreased with lower irradiation temperature. The present results may suggest that the production of free radicals and a radiolysis product is inhibited during gamma irradiation in the frozen state and it may prevent the browning reaction generated by gamma irradiation from occurring.

  10. The role of glycation in the pathogenesis of aging and its prevention through herbal products and physical exercise.

    Science.gov (United States)

    Kim, Chan-Sik; Park, Sok; Kim, Junghyun

    2017-09-30

    Advanced glycation end products (AGEs) are non-enzymatic modifications of proteins or lipids after exposure to sugars. In this review, the glycation process and AGEs are introduced, and the harmful effects of AGEs in the aging process are discussed. Results from human and animal studies examining the mechanisms and effects of AGEs are considered. In addition, publications addressing means to attenuate glycation stress through AGE inhibitors or physical exercise are reviewed. AGEs form in hyperglycemic conditions and/or the natural process of aging. Numerous publications have demonstrated acceleration of the aging process by AGEs. Exogenous AGEs in dietary foods also trigger organ dysfunction and tissue aging. Various herbal supplements or regular physical exercise have beneficial effects on glycemic control and oxidative stress with a consequent reduction of AGE accumulation during aging. The inhibition of AGE formation and accumulation in tissues can lead to an increase in lifespan. ©2017 The Korean Society for Exercise Nutrition

  11. Anti-glycation and anti-oxidation properties of Capsicum frutescens and Curcuma longa fruits: possible role in prevention of diabetic complication.

    Science.gov (United States)

    Khan, Ibrar; Ahmad, Haroon; Ahmad, Bashir

    2014-09-01

    The accumulation of advanced glycationend products (AGE's) in the body, due to the non-enzymatic glycation of proteins is associated with several pathological conditions like aging and diabetes mellitus. Hence a plant having anti-glycation and anti-oxidation potentials may serve as therapeutic agent for diabetic complications and aging. In this study the anti-glycation and anti-oxidation properties of crude methanolic extracts of fruits of Capsicum frutescens and Curcuma longa were investigated. Among the two C. frutescens had more anti-glycation ability with a minimum inhibitory concentration (MIC50) of 90βg/mLas compared to 324βg/mL MIC50 of C. longa. Curcuma longa had the more anti-oxidation potential i.e. 35.01, 30.83 and 28.08% at 0.5mg, 0.25mg and 0.125mg respectively.

  12. Archetypal sandwich-structured CuO for high performance non-enzymatic sensing of glucose

    Science.gov (United States)

    Meher, Sumanta Kumar; Rao, G. Ranga

    2013-02-01

    In the quest to enhance the selectivity and sensitivity of novel structured metal oxides for electrochemical non-enzymatic sensing of glucose, we report here a green synthesis of unique sandwich-structured CuO on a large scale under microwave mediated homogeneous precipitation conditions. The physicochemical studies carried out by XRD and BET methods show that the monoclinic CuO formed via thermal decomposition of Cu2(OH)2CO3 possesses monomodal channel-type pores with largely improved surface area (~43 m2 g-1) and pore volume (0.163 cm3 g-1). The fascinating surface morphology and pore structure of CuO is formulated due to homogeneous crystallization and microwave induced self assembly during synthesis. The cyclic voltammetry and chronoamperometry studies show diffusion controlled glucose oxidation at ~0.6 V (vs. Ag/AgCl) with extremely high sensitivity of 5342.8 μA mM-1 cm-2 and respective detection limit and response time of ~1 μM and ~0.7 s, under a wide dynamic concentration range of glucose. The chronoamperometry measurements demonstrate that the sensitivity of CuO to glucose is unaffected by the absence of dissolved oxygen and presence of poisoning chloride ions in the reaction medium, which essentially implies high poison resistance activity of the sandwich-structured CuO. The sandwich-structured CuO also shows insignificant interference/significant selectivity to glucose, even in the presence of high concentrations of other sugars as well as reducing species. In addition, the sandwich-structured CuO shows excellent reproducibility (relative standard deviation of ~2.4% over ten identically fabricated electrodes) and outstanding long term stability (only ~1.3% loss in sensitivity over a period of one month) during non-enzymatic electrochemical sensing of glucose. The unique microstructure and suitable channel-type pore architecture provide structural stability and maximum accessible electroactive surface for unimpeded mobility of glucose as well as the

  13. Immunoglobulin-G Glycation by Fructose Leads to Structural Perturbations and Drop Off in Free Lysine and Arginine Residues.

    Science.gov (United States)

    Faisal, Mohammad; Alatar, Abdulrahman A; Ahmad, Saheem

    2017-01-01

    Non-enzymatic glycation is the addition of free carbonyl group of reducing sugar to the free amino groups of proteins and leads to the formation of early glycation products and further into advanced glycation end products (AGEs). Fructose reacts rapidly with the free amino groups of proteins to form AGEs. AGEs are believed to be involved in the pathogenesis of several diseases, particularly in diabetic complications. In this study, IgG was glycated with fructose monosaccharide at 10 mM concentration for varying time interval. The reaction mixture was kept at 37ºC. The early glycation of IgG was done by nitroblue tetrazolium assay (NBT), and the generation of AGEs was done by the extent of side chain modifications (lysine and arginine), Nε-carboxymethyl lysine, pentosidine and carbonyl content. The decrease in free lysine and arginine residues suggests that protein 'IgG' has undergone modification specifically on epsilon amino groups of lysine and arginine. Additionally, their fluorescence and absorbance characteristics were also systematically studied. The results suggest that the maximum Amadori product (ketoamine content) was formed on sixth day of the incubation. The conformational structural perturbation was observed within the glycated IgG protein as studied by using various physicochemical techniques. This study reports structural perturbation, formation of various intermediates and AGEs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Products by Glycation Process

    Directory of Open Access Journals (Sweden)

    Liliana Ortega

    2015-01-01

    Full Text Available The antioxidant properties of sweet and acid whey products were incremented by polymerization of their proteins by glycation of whey protein concentrates (WPC and their hydrolyzates (WPCH with ribose and glucose in individual experiments under similar concentration. Heating at 50°C during 20 h maximum and pH 7 and pH 9 were used in all tests. The higher activity was found in WPC glycosylates products with ribose at pH 7 and heating during 10–15 h. In comparable form, antioxidant activity in WPCH was incremented by prior hydrolysis to glycation with 25–45% of hydrolysis degree. Further functional properties of whey proteins (solubility, emulsion, and foam were also improved by the polymerization with ribose. The color of polymerized products due to Maillard reactions was associated with antioxidant activity of each compound; however comparative color in glycosylates products with glucose and ribose did not show this effect.

  15. Effect of temperature towards lipid oxidation and non-enzymatic browning reactions in krill oil upon storage

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Bruheim, I.; Haugsgjerd, B.O.

    2014-01-01

    was assessed by peroxide value and anisidine value, measurement of lipid derived volatiles, lipid classes and antioxidants. The non-enzymatic browning reactions were assessed through the measurement of pyrroles, free amino acids content and Strecker-derived volatiles. The increase of incubation temperature...

  16. Changes in non-enzymatic antioxidant capacity and lipid peroxidation during germination of white, yellow and purple maize seeds

    International Nuclear Information System (INIS)

    Deng, B.; Zhang, Y.; Yang, K.

    2016-01-01

    In this study, the changes in non-enzymatic antioxidant capacity and lipid peroxidation during the germination process of purple, yellow and white maize seeds were compared, under favorable conditions. Results showed that germination can increase non-enzymatic antioxidant capacity (evaluated with ferric reducing power and 2, 2-diphenyl-1-picryl-hydrazyl-hydrate radical scavenging capacity) and lipid peroxidation levels for all these seeds. In addition, non-enzymatic antioxidant capacity observed in the germinating seeds were in the order of purple > yellow > white. However, the highest and lowest levels of lipid peroxidation could be seen during the germination processes of the white and purple seeds, respectively. In addition, the germination rates of the seeds followed the order of white > yellow > purple. Further studies showed that H/sub 2/O/sub 2/ treatment can significantly promote seed germination, especially for purple seeds. In addition, DMTU (dimethylthiourea), a specific scavenger for H/sub 2/O/sub 2/, could slightly but significantly arrest dormancy release. Data analysis showed that a high negative correlation (R/sup 2/ = -0.955) existed between non-enzymatic antioxidant capacity and germination rates. However, a high positive correlation (R/sup 2/ = 0.860) could be detected between lipid peroxidation and germination rates. Finally, lipid peroxidation as a possible novel signaling mechanism for seed germination has been discussed under stress-free conditions. (author)

  17. Prospective randomized study comparing the debriding effect of krill enzymes and a non-enzymatic treatment in venous leg ulcers

    NARCIS (Netherlands)

    Westerhof, W.; van Ginkel, C. J.; Cohen, E. B.; Mekkes, J. R.

    1990-01-01

    The debriding potential of a recently discovered potent enzyme preparation derived from Antarctic krill (Euphausia superba) was compared to a routine non-enzymatic treatment in 31 patients with venous leg ulcers. To assure a reliable interpretation of the cleaning effect, computer image analysis was

  18. Non-enzymatic electrochemical immunoassay using noble metal nanoparticles: a review

    International Nuclear Information System (INIS)

    Tang, Juan; Tang, Dianping

    2015-01-01

    Electrochemical immunodetection has attracted considerable attention due to its high sensitivity, low cost and simplicity. Large efforts have recently made in order to design ultrasensitive assays. Noble metal nanoparticles (NM-NPs) offer advantages such as high conductivity and large surface-to-volume ratio. NM-NPs therefore are excellent candidates for developing electrochemical platforms for immunodetection and as signal tags. The use of biofunctionalized NM-NPs often results in amplified recognition via stronger loading of signal tags, and also in enhanced signal. This review (with 87 references) gives an overview on the current state in the use of NM-NPs in Non-enzymatic electrochemical immunosensing. We discuss the application of NM-NPs as electrode matrices and as electroactive labels (either as a carrier or as electrocatalytic labels), and compare the materials (mainly nanoparticles of gold, platinum, or of bimetallic materials) in terms of performance (for example by increasing sensitivity via label amplification or via high densities of capture molecules). A conclusion covers current challenges and gives an outlook. Rather than being exhaustive, the review focuses on representative examples that illustrate novel concepts and promising applications. NM-NPs based immunosensing opens a series of concepts for basic research and offers new tools for determination of trace amounts of protein-related analytes in environment and clinical applications. (author)

  19. Non-enzymatic detection of urea using unmodified gold nanoparticles based aptasensor.

    Science.gov (United States)

    Kumar, Piyush; Lambadi, Paramesh Ramulu; Navani, Naveen Kumar

    2015-10-15

    Biosensing nitrogenous compounds like urea is required to control the incidents of Economically Motivated Adulteration (EMA). In this study, we report the FluMag Systematic Evolution of Ligands by Exponential Enrichment (FluMag-SELEX) method to isolate a urea specific DNA aptamer with a dissociation constant (Kd) of 232 nM. The interaction of DNA aptamer with urea has been confirmed by affinity assay, CD analysis, melting curve analysis and truncation studies. Unlike other urea sensing methods reported so far, using this urea aptamer, we demonstrate a simple, 'non-enzymatic' easy-to-use, dual readout aptasensor that exploits unmodified gold nanoparticles (AuNPs) to transduce the signals of aptamer binding to urea in terms of intrinsic fluorescence differences and color changes simultaneously. This method is free from complicated sample processing and labeling steps. The urea aptasensor displays high selectivity for urea and is free from interference from common milk adulterants. The developed aptasensor reliably detects urea adulteration in milk. The response signals linearly correlate with the increasing concentrations of urea in milk ranging from 20mM to 150 mM with detection limit of 20mM. We also show that this aptasensor can also be used as a simple fluorescence based "turn-on" sensor. The results obtained in this study are comparable to the commercial urease based detection methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. A non-enzymatic microsurgical dissection technique of mouse embryonic tissues for gene expression profiling applications.

    Science.gov (United States)

    Sun, Li; Lee, May-Yin; Veltmaat, Jacqueline M

    2011-01-01

    With the increased use of gene expression profiling to identify molecular regulators of cellular and developmental mechanisms, developmental biologists face a new challenge in dissecting tissues without cross-contamination or change in RNA profile, and with intact RNA integrity. We have developed a technique that overcomes these problems. We took the dissection of rudimentary mouse embryonic mammary glands as an example, as these structures are particularly difficult to separate from their contiguous ectoderm and strongly adhering mesenchyme. Contrary to conventional enzymatic tissue-separation methods, we blocked transcriptional activity prior to dissection and protected RNA from degradation during dissection, by the use of RNAlater. While RNAlater dehydrates specimens so severely that it interferes with visibility and clean dissection of organs or tissues, we established rehydration conditions that in fact facilitated tissue separation and shortened dissection time to about 10 minutes. The extracted RNA had an excellent quality, rendering it perfectly suitable for transcriptional profiling. Visual inspection of separated tissues and tissue specific gene expression analysis by microarray and RT-PCR confirmed that the tissues were separated with minimal or no cross-contamination. We show that this dissection method can be applied to a broad variety of organs, and that the tissue is still amenable to protein detection. In conclusion, this is a rapid, cheap and effective non-enzymatic tissue separation method which greatly facilitates the exploration of molecular mechanisms in organ formation.

  1. Target-responsive DNA hydrogel for non-enzymatic and visual detection of glucose.

    Science.gov (United States)

    Ma, Yanli; Mao, Yu; An, Yuan; Tian, Tian; Zhang, Huimin; Yan, Jinmao; Zhu, Zhi; Yang, Chaoyong James

    2018-03-26

    We have successfully developed a target-responsive aptamer cross-linked hydrogel for the visual detection of glucose, an important biomedical analyte. In this work, the glucose-responsive hydrogel was prepared using the target aptamer and its two short complementary DNA strands grafted onto a linear polyacrylamide chain as cross-linkers. Gold nanoparticles (AuNPs) modified with thiol-PEG were encapsulated in the gel and used as the output signal for visible detection. The complex of glucose and its ligand of boronic acid derivatives (Shinkai's receptor) can bind with the aptamer to disrupt the hydrogel, leading to the release of AuNPs with a distinct red colour in the supernatant. By this method glucose can be detected with the naked eye, and the sensor has a detection limit of 0.44 mM in buffer with the help of UV-Vis spectrophotometry. Furthermore, glucose spiked in 50% urine and 30% serum could also be detected respectively with the naked eye, and glucose was quantitatively detected in 50% urine. The hydrogel system provides a non-enzymatic and visual method for glucose detection, and offers promising applications in biotechnology and biomedicine.

  2. A nanocomposite-based electrochemical sensor for non-enzymatic detection of hydrogen peroxide.

    Science.gov (United States)

    Du, Xin; Chen, Yuan; Dong, Wenhao; Han, Bingkai; Liu, Min; Chen, Qiang; Zhou, Jun

    2017-02-21

    Hydrogen peroxide (H2O2) plays important signaling roles in normal physiology and disease. However, analyzing the actions of H2O2 is often impeded by the difficulty in detecting this molecule. Herein, we report a novel nanocomposite-based electrochemical sensor for non-enzymatic detection of H2O2. Graphene oxide (GO) was selected as the dopant for the synthesis of polyaniline (PANI), leading to the successful fabrication of a water-soluble and stable GO-PANI composite. GO-PANI was subsequently subject to cyclic voltammetry to generate reduced GO-PANI (rGO-PANI), enhancing the conductivity of the material. Platinum nanoparticles (PtNPs) were then electrodeposited on the surface of the rGO-PANI-modified glassy carbon electrode (GCE) to form an electrochemical H2O2 sensor. Compared to previously reported sensors, the rGO-PANI-PtNP/GCE exhibited an expanded linear range, higher sensitivity, and lower detection limit in the quantification of H2O2. In addition, the sensor displayed outstanding reproducibility and selectivity in real-sample examination. Our study suggests that the rGO-PANI-PtNP/GCE may have broad utility in H2O2 detection under physiological and pathological conditions.

  3. Non-Enzymatic Glucose Sensing Using Carbon Quantum Dots Decorated with Copper Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Houcem Maaoui

    2016-10-01

    Full Text Available Perturbations in glucose homeostasis is critical for human health, as hyperglycemia (defining diabetes leads to premature death caused by macrovascular and microvascular complications. However, the simple and accurate detection of glucose in the blood at low cost remains a challenging task, although it is of great importance for the diagnosis and therapy of diabetic patients. In this work, carbon quantum dots decorated with copper oxide nanostructures (CQDs/Cu2O are prepared by a simple hydrothermal approach, and their potential for electrochemical non-enzymatic glucose sensing is evaluated. The proposed sensor exhibits excellent electrocatalytic activity towards glucose oxidation in alkaline solutions. The glucose sensor is characterized by a wide concentration range from 6 µM to 6 mM, a sensitivity of 2.9 ± 0.2 µA·µM−1·cm−2, and a detection limit of 6 µM at a signal-to-noise ratio S/N = 3. The sensors are successfully applied for glucose determination in human serum samples, demonstrating that the CQDs/Cu2O-based glucose sensor satisfies the requirements of complex sample detection with adapted potential for therapeutic diagnostics.

  4. Resolving the effects of albumin glycation using the quartz crystal microbalance

    Directory of Open Access Journals (Sweden)

    Heller G.T.

    2013-08-01

    Full Text Available Both lysine and arginine residues are particularly important at receptor sites for binding anionic ligands. These receptor sites may become compromised via non-enzymatic glycation. While lysine residues are glycated in the presence of glucose, arginine residues are predominantly glycated by α-oxoaldehydes like glyoxal. This study used a quartz crystal microbalance with dissipation monitoring (QCM-D to examine the binding affinity of surface immobilized human serum albumin (HSA to hemin after the HSA was pre-incubated with glucose or glyoxal. We found it necessary to pre-expose the HSA functionalized crystal surface to hemin to block irreversible unintended interactions. Glycation with glucose showed little affect on HSA’s affinity for hemin, however, modification with glyoxal showed diminished hemin binding capacity. Despite the hemin-blocking step, we were unable to obtain Kd values consistent with those in literature, which we attribute to other unaccounted for nonspecific interactions. This study highlights the need for a kinetic QCM-D analysis method that accounts for unintended interactions at the sensor surface so that the hemin-blocking step may be eliminated.

  5. The effect of Cerasus avium stalk extract on albumin glycation reaction

    Directory of Open Access Journals (Sweden)

    Mohadeseh Abdoli

    2014-10-01

    Full Text Available Background: Non-enzymatic glycosylation of proteins is the major cause of diabetic complications. The inhibition of glycation process can reduce complications of diabetes. In the Iranian traditional medicine, the decoction (boiled extraction of Cerasus avium stalk is used as a hypoglycemic agent. The aim of this study was to investigate the in vitro inhibitory effects of decoction and ethanolic and aqueous extracts of Cerasus avium stalk on albumin glycation reaction. Methods: In this experimental study, first, the ethanolic, aqueous and decoction extracts of Cerasus avium stalk were prepared. Then, different concentrations of these extracts were prepared and added to albumin and glucose solutions. Finally, compared to control group that was not treated with any extracts, the albumin glycation rate in the groups treated with various concentrations of extracts was evaluated using TBA (thio-barbituric acid method. Results: The results showed that compared to control group, decoction of Cerasus avium stalk in the concentrations of 20, 10 and 2 mg/dl could reduce albumin glycation to 85.10±1.55, 72.35±1.75 and 51.25±1.22 %, respectively (P>0.001. Moreover, in the concentration of 20 mg/dl, the inhibitory effect of decoction of Cerasus avium stalk on the albumin glycation reaction was higher than those of aqueous (P=0.021 and ethanolic (P=0.009 extracts. Conclusion: The findings showed that the extracs of Cerasus avium stalk, in particular in the decoction form, could significantly reduce the rate of albumin glycation; therefore, it can be used for decreasing diabetes mellitus complications.

  6. Dietary advanced glycation endproducts

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe

    High heat cooking induces flavor, aroma, and color of food, but leads to formation of advanced glycation endproducts (AGEs) by the Maillard reaction. In addition to the formation in food, AGEs are also formed in vivo, and increased endogenous formation of AGEs has been linked to diabetic complica......High heat cooking induces flavor, aroma, and color of food, but leads to formation of advanced glycation endproducts (AGEs) by the Maillard reaction. In addition to the formation in food, AGEs are also formed in vivo, and increased endogenous formation of AGEs has been linked to diabetic...... complications. A potential pathophysiological role of dietary AGEs in type 2 diabetes and cardiovascular disease has been discussed, as the contribution of dietary AGEs has been estimated to be larger than the amount of endogenously formed AGEs. Furthermore, the increased mortality associated with type 2...... for biological effects of high heat-treated diets in humans. Studies with well-defined AGEs should be undertaken in order to advance our understanding of biological effects of specific AGEs....

  7. Novel synthesis and structural analysis of zinc oxide nanoparticles for the non enzymatic glucose biosensor.

    Science.gov (United States)

    Dayakar, T; Venkateswara Rao, K; Bikshalu, K; Rajendar, V; Park, Si-Hyun

    2017-06-01

    A non-enzymatic glucose biosensor was developed by utilizing the zinc oxide nanoparticles (ZnO NPs) synthesized by a novel green method using the leaf extract of Ocimum tenuiflorum. The structural, optical and morphological properties of ZnO NPs characterized by means of X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, and transmission electron microscopy (TEM). The XRD analysis revealed that the ZnO NPs were crystalline and had a hexagonal wurtzite structure. The crystallite size measured by XRD was the same as that measured using SEM and TEM. The UV-vis absorption spectrum estimates the band gap of ZnO NPs present in the range of 2.82 to 3.45eV. The reduction and formation of ZnO NPs mainly due to the involvement of leaf extract bio-molecular compounds analyzed from the FTIR spectra. The SEM result confirms the morphology of the NPs responsible from the various concentration of leaf extract in the synthesis process. HRTEM analysis depicts the spherical structure of ZnO NPs. The synthesized NPs have the average size ranges from 10 to 20nm. The fabricated GCE/ZnO glucose sensor represents superior electro catalytic activity that has been observed for ZnO NPs with a reproducible sensitivity of 631.30μAmM -1 cm -2 , correlation coefficient of R=0.998, linear dynamic range from 1-8.6mM, low detection limit of 0.043μM (S/N=3) and response time<4s. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Electrodeposition and electrocatalytic properties of Pt/Ni–Co nanowires for non-enzymatic glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Mahshid, Sahar Sadat [Materials Science and Engineering Department, Sharif University of Technology, Tehran 11155-9466 (Iran, Islamic Republic of); State Key Laboratory of Chemo/Biosensing and Chemometrics, Department of Chemistry, Hunan University, Changsha 410082 (China); Mahshid, Sara [School of Engineering, Monash University Sunway Campus, Bandar Sunway 46150 (Malaysia); Dolati, Abolghasem, E-mail: dolati@sharif.edu [Materials Science and Engineering Department, Sharif University of Technology, Tehran 11155-9466 (Iran, Islamic Republic of); Ghorbani, Mohammad [Materials Science and Engineering Department, Sharif University of Technology, Tehran 11155-9466 (Iran, Islamic Republic of); Yang, Lixia [School of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian [State Key Laboratory of Chemo/Biosensing and Chemometrics, Department of Chemistry, Hunan University, Changsha 410082 (China); Cai, Qingyun, E-mail: qycai0001@hnu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, Department of Chemistry, Hunan University, Changsha 410082 (China)

    2013-03-25

    Highlights: ► We fabricate a non-enzyme glucose sensor based on the alloyed nanowires of Pt/Ni–Co. ► We design the process on alternate deposition of metals from single bath. ► Cooperation of Pt, Ni and Co leads to good conductivity and catalytic activity. ► Cooperation of Pt, Ni and Co lowers the applied potential of detection in this electrode. ► This electrode provides good current response in detection of low glucose amount. -- Abstract: A nanowire arrays system consisting of an ordered configuration of Pt, Ni and Co was constructed in single-bath solution through pulse electrodeposition. This structure was evaluated as a potential amperometric non-enzymatic sensor to detect glucose in alkaline solution. We observed a strong and fast amperometric response at low applied potential of 0.4 V vs. SCE over linear ranges of 0–0.2 mM and 0.2–8 mM glucose with sensitivities of 1125 and 333 μA mM{sup −1} cm{sup −2}, respectively. We also observed a low detection limit for glucose of 1 μM. Correlation of the electronic and geometric modifications with the electrochemical performance characteristics enhanced catalytic activity of the electrode by applying the Ni and Co components to Pt nanowires structure. The electrode showed good analytical performance and high selectivity with no interference from other oxidable species, demonstrating its promise for developing an effective glucose sensor.

  9. Changes in Non-Enzymatic Antioxidants in the Blood Following Anaerobic Exercise in Men and Women.

    Directory of Open Access Journals (Sweden)

    Magdalena Wiecek

    Full Text Available The aim of this study was to compare changes in total oxidative status (TOS, total antioxidative capacity (TAC and the concentration of VitA, VitE, VitC, uric acid (UA, reduced (GSH and oxidized glutathione (GSSG in blood within 24 hours following anaerobic exercise (AnEx among men and women.10 women and 10 men performed a 20-second bicycle sprint (AnEx. Concentrations of oxidative stress indicators were measured before AnEx and 3, 15 and 30 minutes and 1 hour afterwards. UA, GSH and GSSH were also measured 24 hours after AnEx. Lactate and H+ concentrations were measured before and 3 minutes after AnEx.The increase in lactate and H+ concentrations following AnEx was similar in both sexes. Changes in the concentrations of all oxidative stress indicators were significant and did not differ between men and women. In both sexes, TOS, TAC, TOS/TAC and VitA and VitE concentrations were the highest 3 minutes, VitC concentration was the highest 30 minutes, and UA concentration was the highest 1 hour after AnEx. GSH concentration was significantly lower than the initial concentration from 15 minutes to 24 hour after AnEx. GSSG concentration was significantly higher, while the GSH/GSSG ratio was significantly lower than the initial values 1 hour and 24 hour after AnEx.With similar changes in lactate and H+ concentrations, AnEx induces the same changes in TAC, TOS, TOS/TAC and non-enzymatic antioxidants of low molecular weight in men and women. Oxidative stress lasted at least 24 hours after AnEx.

  10. Non-enzymatic N-acetylation of Lysine Residues by AcetylCoA Often Occurs via a Proximal S-acetylated Thiol Intermediate Sensitive to Glyoxalase II.

    Science.gov (United States)

    James, Andrew M; Hoogewijs, Kurt; Logan, Angela; Hall, Andrew R; Ding, Shujing; Fearnley, Ian M; Murphy, Michael P

    2017-02-28

    Acetyl coenzyme A (AcCoA), a key intermediate in mitochondrial metabolism, N-acetylates lysine residues, disrupting and, in some cases, regulating protein function. The mitochondrial lysine deacetylase Sirtuin 3 (Sirt3) reverses this modification with benefits reported in diabetes, obesity, and aging. We show that non-enzymatic lysine N-acetylation by AcCoA is greatly enhanced by initial acetylation of a cysteine residue, followed by SN-transfer of the acetyl moiety to a nearby lysine on mitochondrial proteins and synthetic peptides. The frequent occurrence of an S-acetyl intermediate before lysine N-acetylation suggests that proximity to a thioester is a key determinant of lysine susceptibility to acetylation. The thioesterase glyoxalase II (Glo2) can limit protein S-acetylation, thereby preventing subsequent lysine N-acetylation. This suggests that the hitherto obscure role of Glo2 in mitochondria is to act upstream of Sirt3 in minimizing protein N-acetylation, thus limiting protein dysfunction when AcCoA accumulates. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Comparison of the role that entropy has played in processes of non-enzymatic and enzymatic catalysis

    International Nuclear Information System (INIS)

    Dixon Pineda, Manuel Tomas

    2012-01-01

    The function that entropy has played is compared in processes of non-enzymatic and enzymatic catalysis. The processes followed are showed: the kinetics of the acid hydrolysis of 3-pentyl acetate and cyclopentyl acetate catalyzed by hydrochloric acid and enzymatic hydrolysis of ethyl acetate and γ-butyrolactone catalyzed by pig liver esterase. The activation parameters of Eyring were determined for each process and interpreted the contribution of the entropy of activation for catalysis in this type of model reactions. (author) [es

  12. Enzymatic and non-enzymatic antioxidant potentials of Chlorella vulgaris grown in effluent of a confectionery industry

    OpenAIRE

    Kumar, R. Ranjith; Rao, P. Hanumantha; Subramanian, V. V.; Sivasubramanian, V.

    2011-01-01

    Enzymatic and non-enzymatic antioxidant potentials of Chlorella vulgaris have gained considerable importance in recent decades. C. vulgaris strain highly tolerant to extreme pH variations was isolated and mass-cultivated in the wastewater from a confectionery industry. C.vulgaris showed better growth in wastewater than in improvised CFTRI medium. The microalgal biomass was then screened for the following antioxidants: peroxidase, superoxide dismutase, polyphenol oxidase, glutathione peroxidas...

  13. Influence of l-pyroglutamic acid on the color formation process of non-enzymatic browning reactions.

    Science.gov (United States)

    Wegener, Steffen; Kaufmann, Martin; Kroh, Lothar W

    2017-10-01

    Heating aqueous d-glucose model reactions with l-glutamine and l-alanine yielded similar colored solutions. However, size-exclusion chromatography (SEC) revealed that both non-enzymatic browning reactions proceeded differently. Due to a fast occurring cyclization of l-glutamine to pyroglutamic acid, the typical amino-carbonyl reaction was slowed down. However, l-glutamine and l-alanine model reactions showed the same browning index. Closer investigations could prove that l-pyroglutamic acid was able to influence non-enzymatic browning reactions. SEC analyses of d-glucose model reactions with and without l-pyroglutamic acid revealed an increase of low molecular colored compounds in the presence of l-pyroglutamic acid. Polarimetric measurements showed a doubling of d-glucose mutarotation velocity and HPLC analyses of d-fructose formation during thermal treatment indicated a tripling of aldose-ketose transformation in the presence of l-pyroglutamic acid, which are signs of a faster proceeding non-enzymatic browning process. 2-Pyrrolidone showed no such behavior, thus the additional carboxylic group should be responsible for the observed effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Kinetic modelling of non-enzymatic browning and changes of physio-chemical parameters of peach juice during storage.

    Science.gov (United States)

    Lyu, Jian; Liu, Xuan; Bi, Jinfeng; Wu, Xinye; Zhou, Linyan; Ruan, Weihong; Zhou, Mo; Jiao, Yi

    2018-03-01

    Kinetics of non-enzymatic browning and loss of free amino acids during different storage temperature (4, 25, 37 °C) were investigated. Changes of browning degree ( A 420 ), color parameters, Vitamin C ( V c ), free amino acids and 5-hydroxymethylfurfural (5-HMF) were analyzed to evaluate the non-enzymatic browning reactions, which were significantly affected by storage temperature. The lower temperature (4 °C) decreased the loss of V c and the generation of 5-HMF, but induce the highest loss of serine. At the end of storage, loss of serine, alanine and aspartic acid were mainly lost. Results showed that zero-order kinetic model ( R 2  > 0.859), the first-order model ( R 2  > 0.926) and the combined kinetic model ( R 2  > 0.916) were the most appropriate to describe the changes of a * and b * values, the degradation of V c and the changes of A 420 , L * and 5-HMF during different storage temperatures. These kinetic models can be applied for predicting and minimizing the non-enzymatic browning of fresh peach juice during storage.

  15. Non-enzymatic acetylcholine sensor based on Ni–Al layered double hydroxides/ordered mesoporous carbon

    International Nuclear Information System (INIS)

    Ju Jian; Bai Jing; Bo Xiangjie; Guo Liping

    2012-01-01

    Highlights: ► Nanostructured Ni–Al layered double hydroxides supported on ordered mesoporous carbon. ► A non-enzymatic amperometric sensor for acetylcholine. ► High sensitivity, wide linear range, and low limit of detection for acetylcholine. - Abstract: In this work, a novel non-enzymatic acetylcholine (ACh) sensor was constructed based on electrodepoition of Ni–Al layered double hydroxides (Ni–Al LDHs) on ordered mesoporous carbon (OMC) modified glassy carbon (GC) electrode. The obtained Ni–Al LDHs/OMC nanocomposite was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and electrochemical methods. A novel non-enzymatic acetylcholine (ACh) sensor based on Ni–Al LDHs/OMC was developed. Compared with the pristine OMC and Ni–Al LDHs modified electrodes, Ni–Al LDHs/OMC displayed higher electrocatalytic activity toward ACh and gave a wide concentration interval of 2–4922 μM and a low limit of detection (42 nM, R = 0.999), which is better than some reports in the literatures. The sensor also exhibited long-term stability and remarkable antifouling property. The excellent electrocatalysis for ACh can be attributed to the combination of the unique properties of Ni–Al LDHs nanoparticles and the ordered mesostructure of OMCs matrix.

  16. CuO nanoparticles supported on nitrogen and sulfur co-doped graphene nanocomposites for non-enzymatic glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meixia [Hebei University of Engineering, Faculty of Material Science and Engineering (China); Guo, Qingbin, E-mail: guoqingbinhue@163.com [Hebei University of Engineering, Academic Affairs office (China); Xie, Juan; Li, Yongde; Feng, Yapeng [Hebei University of Engineering, Faculty of Material Science and Engineering (China)

    2017-01-15

    Developing highly active catalysts to promote the electrocatalytic glucose oxidation (EGO) is a crucial demand for non-enzymatic glucose sensing. Herein, we reported the use of nitrogen and sulfur co-doped graphene (NSG) as a novel support material for anchoring CuO nanoparticles and obtained CuO/NSG was employed as an efficient EGO catalyst for non-enzymatic glucose sensing. The results showed that the NSG endowed the CuO/NSG with large surface area, increased structural defects, improved conductivity, and strong covalent coupling between NSG and CuO. Owing to the significant contribution of NSG and the synergistic effect of NSG and CuO, the CuO/NSG exhibited a remarkably higher EGO activity than CuO and CuO/reduced graphene oxide. The CuO/NSG-based sensor displayed excellent glucose sensing performances with a considerably low detection limit of 0.07 μM. These findings elucidate that the NSG is a promising support material for non-enzymatic glucose detection.

  17. The browning kinetics of the non-enzymatic browning reaction in L-ascorbic acid/basic amino acid systems

    Directory of Open Access Journals (Sweden)

    Ai-Nong YU

    Full Text Available Abstract Under the conditions of weak basis and the reaction temperature range of 110-150 °C, lysine, arginine and histidine were reacted with L-ascorbic acid at equal amount for 30-150 min, respectively and the formation of browning products was monitored with UV–vis spectrometry. The kinetic characteristics of their non-enzymatic browning reaction were investigated. The study results indicated that the non-enzymatic browning reaction of these three amino acids with L-ascorbic acid to form browning products was zero-order reaction. The apparent activation energies for the formation of browning products from L-ascorbic acid/lysine, L-ascorbic acid/arginine and L-ascorbic acid/histidine systems were 54.94, 50.08 and 35.31kJ/mol. The activation energy data indicated the degree of effects of reaction temperature on non-enzymatic browning reaction. Within the temperature range of 110-150 °C, the reaction rate of L-ascorbic acid/lysine system was the fastest one, followed by that of the L-ascorbic acid/arginine system. The reaction rate of L-ascorbic acid/histidine system was the slowest one. Based on the observed kinetic data, the formation mechanisms of browning products were proposed.

  18. Dietary advanced glycation endproducts

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe

    on postprandial subjective appetite sensations, appetite hormones, and markers of inflammation of two cooking methods that respectively induce or limit AGE formation were investigated in healthy overweight individuals. It was concluded that the meals affected subjective appetite sensations similarly, but the high...... sensitivity of cooking methods that induce or limit AGE formation were investigated in healthy overweight women. It was concluded that insulin sensitivity was improved with use of low heat cooking methods, compared with high heat cooking methods. In a rat study, effects on expression of AGE receptors, insulin......High heat cooking induces flavor, aroma, and color of food, but leads to formation of advanced glycation endproducts (AGEs) by the Maillard reaction. In addition to the formation in food, AGEs are also formed in vivo, and increased endogenous formation of AGEs has been linked to diabetic...

  19. DAF in diabetic patients is subject to glycation/inactivation at its active site residues.

    Science.gov (United States)

    Flückiger, Rudolf; Cocuzzi, Enzo; Nagaraj, Ram H; Shoham, Menachem; Kern, Timothy S; Medof, M Edward

    2018-01-01

    Decay accelerating factor (DAF or CD55) is a cell associated C3 and C5 convertase regulator originally described in terms of protection of self-cells from systemic complement but now known to modulate adaptive T cell responses. It is expressed on all cell types. We investigated whether nonenzymatic glycation could impair its function and potentially be relevant to complications of diabetes mellitus and other conditions that result in nonenzymatic glycation including cancer, Alzheimer's disease, and aging. Immunoblots of affinity-purified DAF from erythrocytes of patients with diabetes showed pentosidine, glyoxal-AGEs, carboxymethyllysine, and argpyrimidine. HPLC/MS analyses of glucose modified DAF localized the sites of AGE modifications to K 125 adjacent to K 126 , K 127 at the junction of CCPs2-3 and spatially near R 96 , and R 100 , all identified as being critical for DAF's function. Functional analyses of glucose or ribose treated DAF protein showed profound loss of its regulatory activity. The data argue that de-regulated activation of systemic complement and de-regulated activation of T cells and leukocytes could result from non-enzymatic glycation of DAF. Copyright © 2017. Published by Elsevier Ltd.

  20. Standardization and quality control in quantifying non-enzymatic oxidative protein modifications in relation to ageing and disease

    DEFF Research Database (Denmark)

    Nedić, Olgica; Rogowska-Wrzesinska, Adelina; Rattan, Suresh I S

    2015-01-01

    Post-translational modifications (PTM) of proteins determine the activity, stability, specificity, transportability and lifespan of a protein. Some PTM are highly specific and regulated involving various enzymatic pathways, but there are other non-enzymatic PTM (nePTM), which occur stochastically...... being fully active to totally inactive molecules. Determination of the type and the amount (abundance) of nePTM is essential for establishing connection between specific protein structure and specific biological role. This article summarizes analytical demands for reliable quantification of ne......PTM, including requirements for the assay performance, standardization and quality control, and points to the difficulties, uncertainties and un-resolved issues....

  1. Synthesis of CdS quantum dots decorated graphene nanosheets and non-enzymatic photoelectrochemical detection of glucose

    International Nuclear Information System (INIS)

    Zhang, Xuyan; Xu, Fang; Zhao, Bingqing; Ji, Xin; Yao, Yanwen; Wu, Dapeng; Gao, Zhiyong; Jiang, Kai

    2014-01-01

    Graphical abstract: - Highlights: • Graphene-CdS hybrid materials were prepared via one-step hydrothermal method. • Graphene-CdS was used as non-enzymatic photoelectrochemical sensor to detect glucose. • Glucose in real sample was detected and showed good specificity and sensitivity. - ABSTRACT: Graphene-CdS quantum dots (QDs) hybrid materials were successfully prepared via one-step hydrothermal method. CdS QDs with average size of ∼6 nm were dispersed on graphene sheets with high coverage through non-covalent bonding. Photocurrent and electrochemical impedance spectroscopy (EIS) results suggested that the best dosage of graphene oxide for graphene-CdS hybrid materials is 0.5% (G0.5-CdS). When G0.5-CdS QDs was used as photoanode materials in non-enzymatic sensor, and the sensor was used to detect glucose and displayed satisfactory analytical performance with good linear range from 0.1∼4 mmol dm −3 with a detection limit of 7 μmol dm −3 at a signal-to-noise ratio of 3. The sensor also possessed high selectivity and durability in trace detection of glucose

  2. Non-enzymatic lipid oxidation products in biological systems: assessment of the metabolites from polyunsaturated fatty acids.

    Science.gov (United States)

    Vigor, Claire; Bertrand-Michel, Justine; Pinot, Edith; Oger, Camille; Vercauteren, Joseph; Le Faouder, Pauline; Galano, Jean-Marie; Lee, Jetty Chung-Yung; Durand, Thierry

    2014-08-01

    Metabolites of non-enzymatic lipid peroxidation of polyunsaturated fatty acids notably omega-3 and omega-6 fatty acids have become important biomarkers of lipid products. Especially the arachidonic acid-derived F2-isoprostanes are the classic in vivo biomarker for oxidative stress in biological systems. In recent years other isoprostanes from eicosapentaenoic, docosahexaenoic, adrenic and α-linolenic acids have been evaluated, namely F3-isoprostanes, F4-neuroprostanes, F2-dihomo-isoprostanes and F1-phytoprostanes, respectively. These have been gaining interest as complementary specific biomarkers in human diseases. Refined extraction methods, robust analysis and elucidation of chemical structures have improved the sensitivity of detection in biological tissues and fluids. Previously the main reliable instrumentation for measurement was gas chromatography-mass spectrometry (GC-MS), but now the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunological techniques is gaining much attention. In this review, the types of prostanoids generated from non-enzymatic lipid peroxidation of some important omega-3 and omega-6 fatty acids and biological samples that have been determined by GC-MS and LC-MS/MS are discussed. Copyright © 2014. Published by Elsevier B.V.

  3. A high performance non-enzymatic glucose sensor based on nickel hydroxide modified nitrogen-incorporated nanodiamonds.

    Science.gov (United States)

    Ko, Chih-Yu; Huang, Jin-Hua; Raina, Supil; Kang, Weng P

    2013-06-07

    A highly selective, sensitive, and stable non-enzymatic glucose sensor based on Ni hydroxide modified nitrogen-incorporated nanodiamonds (Ni(OH)2-NND) was developed. The sensor was fabricated by e-beam evaporation of a thin Ni film on NND followed by the growth of Ni(OH)2 using an electrochemical process. It was found that the Ni film thickness greatly affects the morphology and electro-catalytic activity of the as-synthesized electrode for non-enzymatic glucose oxidation. Owing to its nanostructure characteristics, the best sensor fabricated by 150 nm Ni deposition showed two wide response ranges, namely, 0.02-1 mM and 1-9 mM, with sensitivities of 3.20 and 1.41 mA mM(-1) cm(-2), respectively, and a detection limit of 1.2 μM (S/N = 3). The sensor also showed good long-term stability as well as high selectivity in the presence of interferences such as ascorbic acid, acetaminophen, and uric acid. This finding reveals the possibility of exploiting the NND as an electrochemical biosensor platform where high performance addressable sensor arrays could be built.

  4. Highly Dispersed NiO Nanoparticles Decorating graphene Nanosheets for Non-enzymatic Glucose Sensor and Biofuel Cell

    Science.gov (United States)

    Zeng, Guisheng; Li, Weiping; Ci, Suqin; Jia, Jingchun; Wen, Zhenhai

    2016-11-01

    Nickel oxide-decorated graphene nanosheet (NiO/GNS), as a novel non-enzymatic electrocatalyst for glucose oxidation reaction (GOR), was synthesized through a facile hydrothermal route followed by the heat treatment. The successful synthesis of NiO/GNS was characterized by a series of techniques including XRD, BET, SEM and TEM. Significantly, the NiO/GNS catalyst show excellent catalytic activity toward GOR, and was employed to develop a sensitive non-enzymatic glucose sensor. The developed glucose sensor could response to glucose in a wide range from 5 μM-4.2 mM with a low detection limit (LOD) of 5.0 μM (S/N = 3). Importantly, compared with bare NiO, the catalytic activity of NiO/GNS was much higher. The reason might be that the 2D structure of graphene could prevent the aggregation of NiO and facilitate the electron transfer at electrode interface. Moreover, the outstanding catalytic activity of NiO/GNS was further demonstrated by applying it to construct a biofuel cell using glucose as fuel, which exhibited high stability and current density.

  5. Flexible electronics-compatible non-enzymatic glucose sensing via transparent CuO nanowire networks on PET films

    Science.gov (United States)

    Bell, Caroline; Nammari, Abdullah; Uttamchandani, Pranay; Rai, Amit; Shah, Pujan; Moore, Arden L.

    2017-06-01

    Diabetic individuals need simple, accurate, and cost effective means by which to independently assess their glucose levels in a non-invasive way. In this work, a sensor based on randomly oriented CuO nanowire networks supported by a polyethylene terephthalate thin film is evaluated as a flexible, transparent, non-enzymatic glucose sensing system analogous to those envisioned for future wearable diagnostic devices. The amperometric sensing characteristics of this type of device architecture are evaluated both before and after bending, with the system’s glucose response, sensitivity, lower limit of detection, and effect of applied bias being experimentally determined. The obtained data shows that the sensor is capable of measuring changes in glucose levels within a physiologically relevant range (0-12 mM glucose) and at lower limits of detection (0.05 mM glucose at +0.6 V bias) consistent with patient tears and saliva. Unlike existing studies utilizing a conductive backing layer or macroscopic electrode setup, this sensor demonstrates a percolation network-like trend of current versus glucose concentration. In this implementation, controlling the architectural details of the CuO nanowire network could conceivably allow the sensor’s sensitivity and optimal sensing range to be tuned. Overall, this work shows that integrating CuO nanowires into a sensor architecture compatible with transparent, flexible electronics is a promising avenue to realizing next generation wearable non-enzymatic glucose diagnostic devices.

  6. Enhanced sensitivity in non-enzymatic glucose detection by improved growth kinetics of Ni-based nanostructures

    Science.gov (United States)

    Urso, M.; Pellegrino, G.; Strano, V.; Bruno, E.; Priolo, F.; Mirabella, S.

    2018-04-01

    Ni-based nanostructures are attractive catalytic materials for many electrochemical applications, among which are non-enzymatic sensing, charge storage, and water splitting. In this work, we clarify the synthesis kinetics of Ni(OH)2/NiOOH nanowalls grown by chemical bath deposition at room temperature and at 50 °C. We applied the results to non-enzymatic glucose sensing, reaching a highest sensitivity of 31 mA cm-2mM-1. Using scanning electron microscopy, x-ray diffraction analysis and Rutherford backscattering spectrometry we found that the growth occurs through two regimes: first, a quick random growth leading to disordered sheets of Ni oxy-hydroxide, followed by a slower growth of well-aligned sheets of Ni hydroxide. A high growth temperature (50 °C), leading mainly to well-aligned sheets, offers superior electrochemical properties in terms of charge storage, charge carrier transport and catalytic action, as confirmed by cyclic voltammetry and electrochemical impedance spectroscopy analyses. The reported results on the optimization and application of low-cost synthesis of these Ni-based nanostructures have a large potential for application in catalysis, (bio)sensing, and supercapacitors areas.

  7. Heterogeneous glycation of cancellous bone and its association with bone quality and fragility.

    Directory of Open Access Journals (Sweden)

    Lamya Karim

    Full Text Available Non-enzymatic glycation (NEG and enzymatic biochemical processes create crosslinks that modify the extracellular matrix (ECM and affect the turnover of bone tissue. Because NEG affects turnover and turnover at the local level affects microarchitecture and formation and removal of microdamage, we hypothesized that NEG in cancellous bone is heterogeneous and accounts partly for the contribution of microarchitecture and microdamage on bone fragility. Human trabecular bone cores from 23 donors were subjected to compression tests. Mechanically tested cores as well as an additional 19 cores were stained with lead-uranyl acetate and imaged to determine microarchitecture and measure microdamage. Post-yield mechanical properties were measured and damaged trabeculae were extracted from a subset of specimens and characterized for the morphology of induced microdamage. Tested specimens and extracted trabeculae were quantified for enzymatic and non-enzymatic crosslink content using a colorimetric assay and Ultra-high Performance Liquid Chromatography (UPLC. Results show that an increase in enzymatic crosslinks was beneficial for bone where they were associated with increased toughness and decreased microdamage. Conversely, bone with increased NEG required less strain to reach failure and were less tough. NEG heterogeneously modified trabecular microarchitecture where high amounts of NEG crosslinks were found in trabecular rods and with the mechanically deleterious form of microdamage (linear microcracks. The extent of NEG in tibial cancellous bone was the dominant predictor of bone fragility and was associated with changes in microarchitecture and microdamage.

  8. Inhibition of protein glycation and advanced glycation end products ...

    African Journals Online (AJOL)

    Advanced glycation end products (AGEs) formation is increased in diabetes mellitus, leading to microvascular and macrovascular complications. Recently, much attention has been focused on natural and synthetic inhibitors to delay the onset or progression of diabetes and its comorbidities. Ascorbic acid (AA) can react with ...

  9. The isotopic exchange of oxygen as a tool for detection of the glycation sites in proteins.

    Science.gov (United States)

    Kijewska, Monika; Stefanowicz, Piotr; Kluczyk, Alicja; Szewczuk, Zbigniew

    2011-12-15

    A nonenzymatic reaction of reducing sugars with the free amino group located at the N terminus of the polypeptide chain or in the lysine side chain results in glycation of proteins. The fragments of glycated proteins obtained by enzymatic hydrolysis could be considered as the biomarkers of both the aging process and diabetes mellitus. Here we propose a new method for the identification of peptide-derived Amadori products in the enzymatic digest of glycated proteins. The products of enzymatic hydrolysis of the model protein ubiquitin were incubated with H(2)(18)O under microwave activation. We observed that at these conditions the Amadori compounds selectively exchange one oxygen atom in the hexose moiety. The characteristic isotopic pattern of Amadori products treated with H(2)(18)O allows fast and convenient identification of this group of compounds, whereas nonglycated peptides are not susceptible to isotopic exchange. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Effect of Cadmium Stress on Non-enzymatic Antioxidant and Nitric Oxide Levels in Two Varieties of Maize (Zea mays).

    Science.gov (United States)

    Akinyemi, Ayodele Jacob; Faboya, Oluwabamise Lekan; Olayide, Israel; Faboya, Opeyemi Ayodeji; Ijabadeniyi, Tosin

    2017-06-01

    Cadmium (Cd) is one of the most toxic heavy metals that inhibit physiological processes of plants. Hence, the present study sought to investigate the effect of cadmium-contaminated seeds from two varieties of maize (Zea mays) on non-enzymatic antioxidant and nitric oxide levels. Seeds of yellow and white maize were exposed to different concentrations of Cd (0, 1, 3 and 5 ppm) for two weeks. The results from this study revealed that both varieties of maize bio-accumulate Cd in leaves in a dose-dependent manner. In addition, Cd exposure caused a significant (p < 0.05) decrease in total phenolic, GSH and nitric oxide (NO) levels at the highest concentration tested when compared with control. Therefore, the observed decrease in NO and endogenous antioxidant status by Cd treatment in maize plants could suggest some possible mechanism of action for Cd-induced oxidative stress and counteracting effect of the plants against Cd toxicity.

  11. One-pot non-enzymatic formation of firefly luciferin in a neutral buffer from p-benzoquinone and cysteine.

    Science.gov (United States)

    Kanie, Shusei; Nishikawa, Toshio; Ojika, Makoto; Oba, Yuichi

    2016-04-21

    Firefly luciferin, the substrate for the bioluminescence reaction of luminous beetles, possesses a benzothiazole ring, which is rare in nature. Here, we demonstrate a novel one-pot reaction to give firefly luciferin in a neutral buffer from p-benzoquinone and cysteine without any synthetic reagents or enzymes. The formation of firefly luciferin was low in yield in various neutral buffers, whereas it was inhibited or completely prevented in acidic or basic buffers, in organic solvents, or under a nitrogen atmosphere. Labelling analysis of the firefly luciferin using stable isotopic cysteines showed that the benzothiazole ring was formed via the decarboxylation and carbon-sulfur bond rearrangement of cysteine. These findings imply that the biosynthesis of firefly luciferin can be developed/evolved from the non-enzymatic production of firefly luciferin using common primary biosynthetic units, p-benzoquinone and cysteine.

  12. Phosphomolybdic acid functionalized graphene loading copper nanoparticles modified electrodes for non-enzymatic electrochemical sensing of glucose

    International Nuclear Information System (INIS)

    Xu, Jiaoyan; Cao, Xiyue; Xia, Jianfei; Gong, Shida; Wang, Zonghua; Lu, Lin

    2016-01-01

    A sensitive non-enzymatic glucose electrochemical biosensor (Cu/PMo 12 -GR/GCE) was developed based on the combination of copper nanoparticles (CuNPs) and phosphomolybdic acid functionalized graphene (PMo 12 -GR). PMo 12 -GR films were modified on the surface of glassy carbon electrode (GCE) through electrostatic self-assembly with the aid of poly diallyl dimethyl ammonium chloride (PDDA). Then CuNPs were successfully decorated onto the PMo 12 -GR modified GCE through electrodeposition. The morphology of Cu/PMo 12 -GR/GCE was characterized by scanning electron microscope (SEM). Cyclic voltammetry (CV) and chronoamperometry were used to investigate the electrochemical performances of the biosensor. The results indicated that the modified electrode displayed a synergistic effect of PMo 12 -GR sheets and CuNPs towards the electro-oxidation of glucose in the alkaline solution. At the optimal detection potential of 0.50 V, the response towards glucose presented a linear response ranging from 0.10 μM to 1.0 mM with a detection limit of 3.0 × 10 −2  μM (S/N = 3). In addition, Cu/PMo 12 -GR/GCE possessed a high selectivity, good reproducibility, excellent stability and acceptable recovery, which indicating the potential application in clinical field. - Highlights: • Cu/PMo 12 -GR/GCE as a non-enzymatic glucose electrochemical sensor. • PMo 12 is efficient for the uniform growth of Cu-NPs and electron transport. • The sensor exhibits good sensitivity and specificity towards glucose.

  13. Phosphomolybdic acid functionalized graphene loading copper nanoparticles modified electrodes for non-enzymatic electrochemical sensing of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jiaoyan; Cao, Xiyue [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Xia, Jianfei, E-mail: xiajianfei@126.com [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Gong, Shida [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Wang, Zonghua, E-mail: wangzonghua@qdu.edu.cn [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Lu, Lin [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Zibo Normal College, Zibo, Shandong 255100 (China)

    2016-08-31

    A sensitive non-enzymatic glucose electrochemical biosensor (Cu/PMo{sub 12}-GR/GCE) was developed based on the combination of copper nanoparticles (CuNPs) and phosphomolybdic acid functionalized graphene (PMo{sub 12}-GR). PMo{sub 12}-GR films were modified on the surface of glassy carbon electrode (GCE) through electrostatic self-assembly with the aid of poly diallyl dimethyl ammonium chloride (PDDA). Then CuNPs were successfully decorated onto the PMo{sub 12}-GR modified GCE through electrodeposition. The morphology of Cu/PMo{sub 12}-GR/GCE was characterized by scanning electron microscope (SEM). Cyclic voltammetry (CV) and chronoamperometry were used to investigate the electrochemical performances of the biosensor. The results indicated that the modified electrode displayed a synergistic effect of PMo{sub 12}-GR sheets and CuNPs towards the electro-oxidation of glucose in the alkaline solution. At the optimal detection potential of 0.50 V, the response towards glucose presented a linear response ranging from 0.10 μM to 1.0 mM with a detection limit of 3.0 × 10{sup −2} μM (S/N = 3). In addition, Cu/PMo{sub 12}-GR/GCE possessed a high selectivity, good reproducibility, excellent stability and acceptable recovery, which indicating the potential application in clinical field. - Highlights: • Cu/PMo{sub 12}-GR/GCE as a non-enzymatic glucose electrochemical sensor. • PMo{sub 12} is efficient for the uniform growth of Cu-NPs and electron transport. • The sensor exhibits good sensitivity and specificity towards glucose.

  14. Uptake of advanced glycation end products by proximal tubule epithelial cells via macropinocytosis.

    Science.gov (United States)

    Gallicchio, Marisa A; Bach, Leon A

    2013-12-01

    Chronic hyperglycaemia during diabetes leads to non-enzymatic glycation of proteins to form advanced glycation end products (AGEs) that contribute to nephropathy. We describe AGE uptake in LLC-PK1 and HK2 proximal tubule cell lines by macropinocytosis, a non-specific, endocytic mechanism. AGE-BSA induced dorsal circular actin ruffles and amiloride-sensitive dextran-TRITC uptake, significantly increased AGE-BSA-FITC uptake (167±20% vs BSA control, pmacropinocytosis. PAK1 and PIP5Kγ siRNA significantly decreased AGE-BSA-FITC uptake (81±6% and 64±7%, respectively, pmacropinocytosis inhibitors and a neutralising TGF-β antibody, reversed the AGE-induced decrease in surface Na(+)K(+)ATPase, suggesting AGE uptake by macropinocytosis may contribute to diabetic kidney fibrosis and/or EMT by modulating this pump. Understanding methods of cellular uptake and signalling by AGEs may lead to novel therapies for diabetic nephropathy. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Binderless solution processed Zn doped Co3O4 film on FTO for rapid and selective non-enzymatic glucose detection

    CSIR Research Space (South Africa)

    Chowdhury, M

    2016-09-01

    Full Text Available A simple solution based deposition process has been used to fabricate Zn doped Co(sub3)O(sub4) electrode as an electrocatalyst for non-enzymatic oxidation of glucose. XRD, HRTEM, SEM, EELS, AFM, EIS was used to characterise the electrode...

  16. Non-enzymatic amperometric sensor for hydrogen peroxide based on a biocomposite made from chitosan, hemoglobin, and silver nanoparticles

    International Nuclear Information System (INIS)

    Tian, L.; Feng, Y.; Qi, Y.; Wang, B.; Chen, Y.; Fu, X.

    2012-01-01

    We report on a novel non-enzymatic sensor for hydrogen peroxide (HP) that is based on a biocomposite made up from chitosan (CS), hemoglobin (Hb), and silver nanoparticles (AgNPs). The AgNPs were prepared in the presence of CS and glucose in an ultrasonic bath, and CS is found to act as a stabilizing agent. They were then combined with Hb and CS to construct a carbon paste biosensor. The resulting electrode gave a well-defined redox couple for Hb, with a formal potential of about -0.17 V (vs. SCE) at pH 6. 86 and exhibited a remarkable electrocatalytic activity for the reduction of HP. The sensor was used to detect HP by flow injection analysis, and a linear response is obtained in the 0. 08 to 250 μM concentration range. The detection limit is 0.05 μM (at S/N = 3). These characteristics, along with its long-term stability make the sensor highly promising for the amperometric determination of HP. (author)

  17. Nanoporous Carbon Nanofibers Decorated with Platinum Nanoparticles for Non-Enzymatic Electrochemical Sensing of H2O2

    Directory of Open Access Journals (Sweden)

    Yang Li

    2015-11-01

    Full Text Available We describe the preparation of nanoporous carbon nanofibers (CNFs decorated with platinum nanoparticles (PtNPs in this work by electrospining polyacrylonitrile (PAN nanofibers and subsequent carbonization and binding of PtNPs. The fabricated nanoporous CNF-PtNP hybrids were further utilized to modify glass carbon electrodes and used for the non-enzymatic amperometric biosensor for the highly sensitive detection of hydrogen peroxide (H2O2. The morphologies of the fabricated nanoporous CNF-PtNP hybrids were observed by scanning electron microscopy, transmission electron microscopy, and their structure was further investigated with Brunauer–Emmett–Teller (BET surface area analysis, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectrum. The cyclic voltammetry experiments indicate that CNF-PtNP modified electrodes have high electrocatalytic activity toward H2O2 and the chronoamperometry measurements illustrate that the fabricated biosensor has a high sensitivity for detecting H2O2. We anticipate that the strategies utilized in this work will not only guide the further design and fabrication of functional nanofiber-based biomaterials and nanodevices, but also extend the potential applications in energy storage, cytology, and tissue engineering.

  18. Non-enzymatic glucose sensing properties of MoO3 nanorods: experimental and density functional theory investigations

    Science.gov (United States)

    Sharma, Maneesha; Gangan, Abhijeet; Chakraborty, Brahmananda; Sekhar Rout, Chandra

    2017-11-01

    We report the growth of monoclinic MoO3 nanorods by a simple and highly reproducible hydrothermal method. Structural and morphological studies provide significant insights about the phase and crystalline structure of the synthesized samples. Further, the non-enzymatic glucose sensing properties were investigated and the MoO3 nanorods exhibited a sensitivity of 15.4 µA µM‑1 cm‑2 in the 5–175 µM linear range. Also, a quick response time of 8 s towards glucose molecules was observed, exhibiting an excellent electrochemical activity. We have also performed density functional theory (DFT) simulations to qualitatively support our experimental observations by investigating the interactions and charge-transfer mechanism of glucose on MoO3. There is a strong interaction between glucose and the MoO3 surface due to charge transfer from a bonded O atom of glucose to a Mo atom of MoO3 resulting in a strong hybridization between the p orbital of O and d orbital of Mo. Thus, the MoO3 nanorod-based electrodes are found to be good glucose sensing materials for practical industrial applications.

  19. Cell-cycle regulation of non-enzymatic functions of the Drosophila methyltransferase PR-Set7.

    Science.gov (United States)

    Zouaz, Amel; Fernando, Céline; Perez, Yannick; Sardet, Claude; Julien, Eric; Grimaud, Charlotte

    2018-04-06

    Tight cell-cycle regulation of the histone H4-K20 methyltransferase PR-Set7 is essential for the maintenance of genome integrity. In mammals, this mainly involves the interaction of PR-Set7 with the replication factor PCNA, which triggers the degradation of the enzyme by the CRL4CDT2 E3 ubiquitin ligase. PR-Set7 is also targeted by the SCFβ-TRCP ligase, but the role of this additional regulatory pathway remains unclear. Here, we show that Drosophila PR-Set7 undergoes a cell-cycle proteolytic regulation, independently of its interaction with PCNA. Instead, Slimb, the ortholog of β-TRCP, is specifically required for the degradation of the nuclear pool of PR-Set7 prior to S phase. Consequently, inactivation of Slimb leads to nuclear accumulation of PR-Set7, which triggers aberrant chromatin compaction and G1/S arrest. Strikingly, these phenotypes result from non-enzymatic PR-Set7 functions that prevent proper histone H4 acetylation independently of H4K20 methylation. Altogether, these results identify the Slimb-mediated PR-Set7 proteolysis as a new critical regulatory mechanism required for proper interphase chromatin organization at G1/S transition.

  20. Pulse electrodeposited nickel-indium tin oxide nanocomposite as an electrocatalyst for non-enzymatic glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Sivasakthi, P.; Ramesh Bapu, G.N.K., E-mail: rameshbapugnk@cecri.res.in; Chandrasekaran, Maruthai

    2016-01-01

    Nickel and nickel-ITO nanocomposite on mild steel substrate were prepared by pulse electrodeposition method from nickel sulphamate electrolyte and were examined as electrocatalysts for non-enzymatic glucose sensing. The surface morphology, chemical composition, preferred orientation and oxidation states of the nickel metal ion in the deposits were characterized by SEM, EDAX, XRD and XPS. Electrochemical sensing of glucose was studied by cyclic voltammetry and amperometry. The modified Ni-ITO nanocomposite electrode showed higher electrocatalytic activity for the oxidation of glucose in alkaline medium and exhibited a linear range from 0.02 to 3.00 mM with a limit of detection 3.74 μM at a signal-to-noise ratio of 3. The higher selectivity, longer stability and better reproducibility of this electrode compared to nickel in the sensing of glucose are pointers for exploitation in practical clinical applications. - Highlights: • Ni-ITO nanocomposites are prepared by pulse electrocodeposition method from nickel sulphamate solutions. • Ni-ITO nanocomposites are characterized using SEM, EDAX, XRD and XPS. • Electrochemical characteristics of the Ni and Ni-ITO nanocomposite deposits are studied by CV and amperometry techniques. • Ni-ITO nanocomposite electrode could be used as sensing material for detection of glucose in practical condition.

  1. Molecular Investigation of the Mechanism of Non-Enzymatic Hydrolysis of Proteins and the Predictive Algorithm for Susceptibility.

    Science.gov (United States)

    Lauer, Timothy M; Wood, Geoffrey P F; Farkas, David; Sathish, Hasige A; Samra, Hardeep S; Trout, Bernhardt L

    2016-06-14

    A number of potential degradation routes can limit the shelf life of a biotherapeutic. While these are experimentally measurable, the tests to do so require a substantial investment in both time and material, resources rarely available early in the drug development process. To address the potential degradation route of non-enzymatic hydrolysis, we performed a molecular modeling analysis, together with an experimental study, to gain detailed insight into the reaction. On the basis of the mechanism, an algorithm for predicting the likely cleavage sites of a protein has been created. This algorithm measures four key properties during a molecular dynamics simulation, which relate to the key steps of the hydrolysis mechanism, in particular the rate-determining step (which can vary depending on the local environment). The first two properties include the secondary structure and the surface exposure of the amide bond, both of which help detect if the addition of the proton to the amide bond is possible. The second two properties relate to whether the side chain can cyclize and form a furane ring. These two properties are the orientation of the side chain relative to the amide bond and the number of hydrogen bonds between the side chain and the surrounding protein. Overall, the algorithm performs well at identifying reactive versus nonreactive bonds. The algorithm correctly classifies nearly 90% of all amide bonds following an aspartic or glutamic acid residue as reactive or nonreactive.

  2. Electrochemical behavior of Azure A/gold nanoclusters modified electrode and its application as non-enzymatic hydrogen peroxide sensor.

    Science.gov (United States)

    Priya, C; Sivasankari, G; Narayanan, S Sriman

    2012-09-01

    A novel non-enzymatic hydrogen peroxide sensor was developed using Azure A/gold nanoclusters modified graphite electrode. The method of preparation of Azure A/gold nanoclusters was simple and it was characterized by UV-visible spectroscopy, field emission scanning electron microscopy (FESEM) and confocal Raman microscopy. The electrochemical properties of Azure A/gold nanoclusters modified graphite electrode was characterized by cyclic voltammetry. In 0.1M H(2)SO(4) the modified electrode showed redox peaks which correspond to the redox behavior of gold nanoparticle. In 0.1M PBS the modified electrode exhibited well defined redox peaks with the formal potential of -0.253 V which is analogous to the redox reaction of Azure A. The results have shown that the gold nanoclusters has reduced the formal potential of Azure A and enhanced the current due to the fast charge transfer kinetics. Also the modified electrode showed an enhanced electrocatalytic activity towards the reduction of H(2)O(2) in the concentration range of 3.26×10(-6)M to 3.2×10(-3)M with a detection limit of 1.08×10(-6)M (S/N=3). The proposed electrode exhibited good stability and reproducibility, and it has the potential application as a sensor for other biologically significant compounds. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Non-enzymatic detection of glucose using poly(azure A)-nickel modified glassy carbon electrode.

    Science.gov (United States)

    Liu, Tong; Luo, Yiqun; Zhu, Jiaming; Kong, Liyan; Wang, Wen; Tan, Liang

    2016-08-15

    A simple, sensitive and selective non-enzymatic glucose sensor was constructed in this paper. The poly(azure A)-nickel modified glassy carbon electrode was successfully fabricated by the electropolymerization of azure A and the adsorption of Ni(2+). The Ni modified electrode, which was characterized by scanning electron microscope, cyclic voltammetry, electrochemical impedance spectra and X-ray photoelectron spectroscopy measurements, respectively, displayed well-defined current responses of the Ni(III)/Ni(II) couple and showed a good activity for electrocatalytic oxidation of glucose in alkaline medium. Under the optimized conditions, the developed sensor exhibited a broad linear calibration range of 5 μM-12mM for quantification of glucose and a low detection limit of 0.64μM (3σ). The excellent analytical performance including simple structure, fast response time, good anti-interference ability, satisfying stability and reliable reproducibility were also found from the proposed amperometric sensor. The results were satisfactory for the determination of glucose in human serum samples as comparison to those from a local hospital. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Non-enzymatic detection of glucose in fruits using TiO2-Mn3O4 hybrid nano interface

    Science.gov (United States)

    Jayanth Babu, K.; Sasya, Madhurantakam; Nesakumar, Noel; Shankar, Prabakaran; Gumpu, Manju Bhargavi; Ramachandra, Bhat Lakshmishri; Kulandaisamy, Arockia Jayalatha; Rayappan, John Bosco Balaguru

    2017-08-01

    Consumption of fruits leads to increase in glucose level in blood for diabetic patients, which in turn leads to peripheral, vascular, ocular complications and cardiac diseases. In this context, a non-enzymatic hybrid glucose biosensor was fabricated for the first time to detect glucose by immobilizing titanium oxide-manganese oxide (TiO2-Mn3O4) nanocomposite and chitosan membrane on to the surface of Pt working electrode (Pt/TiO2-Mn3O4/chitosan). TiO2-Mn3O4 nanocomposite catalyzed the oxidation of glucose to gluconolactone in the absence of glucose oxidase enzyme with high electron transfer rate, good biocompatibility and large surface coverage. Electrochemical measurements revealed the excellent sensing response of the developed biosensor towards glucose with a high sensitivity of 7.073 µA mM-1, linearity of 0.01-0.1 mM, low detection limit of 0.01 µM, reproducibility of 1.5% and stability of 98.8%. The electrochemical parameters estimated from the anodic process were subjected to linear regression models for the detection of unknown concentration of glucose in different fruit samples.

  5. Novel synthesis and characterization of Ag@TiO2 core shell nanostructure for non-enzymatic glucose sensor

    Science.gov (United States)

    T, Dayakar; Venkateswara Rao, K.; Vinodkumar, M.; Bikshalu, K.; Chakradhar, B.; Ramachandra Rao, K.

    2018-03-01

    Ag@TiO2 core-shell nano composite (ATCSNC) were synthesized by using Ocimum tenuiflorum leaves extract through a simple one-step hydrothermal route for Non-enzymatic glucose sensing material. The prepared NCs were characterized and found high crystallinity, red shift absorbance, interface-bonding parameters, rough surface and network like microstructure through XRD, Uv-vis, FTIR, SEM, and TEM. The prepared ATCSNC have been used for fabrication of glassy carbon electrode (GCE) and the same was applied to test its electro catalytic activity of glucose in 0.1 M NaOH. The promising results were recorded for ATCSNC/GCE with a high sensitivity (1968.72 μAm M-1cm-2), wide linear range (1 μM-8.1 mM), good response time (3 s), and excellent low detection limit (0.19 μM, S/N = 3). Furthermore, the designed sensor exhibits admirable stability and reproducibility, as well as attractive achievability for real sample analysis. As such, the proposed ATCSNC could be highly beneficial in the development of sustainable and eco-friendly glucose sensing devices.

  6. The Development of Non-Enzymatic Glucose Biosensors Based on Electrochemically Prepared Polypyrrole–Chitosan–Titanium Dioxide Nanocomposite Films

    Directory of Open Access Journals (Sweden)

    Ali M. A. Abdul Amir AL-Mokaram

    2017-05-01

    Full Text Available The performance of a modified electrode of nanocomposite films consisting of polypyrrole–chitosan–titanium dioxide (Ppy-CS-TiO2 has been explored for the developing a non-enzymatic glucose biosensors. The synergy effect of TiO2 nanoparticles (NPs and conducting polymer on the current responses of the electrode resulted in greater sensitivity. The incorporation of TiO2 NPs in the nanocomposite films was confirmed by X-ray photoelectron spectroscopy (XPS spectra. FE-SEM and HR-TEM provided more evidence for the presence of TiO2 in the Ppy-CS structure. Glucose biosensing properties were determined by amperommetry and cyclic voltammetry (CV. The interfacial properties of nanocomposite electrodes were studied by electrochemical impedance spectroscopy (EIS. The developed biosensors showed good sensitivity over a linear range of 1–14 mM with a detection limit of 614 μM for glucose. The modified electrode with Ppy-CS nanocomposite also exhibited good selectivity and long-term stability with no interference effect. The Ppy-CS-TiO2 nanocomposites films presented high electron transfer kinetics. This work shows the role of nanomaterials in electrochemical biosensors and describes the process of their homogeneous distribution in composite films by a one-step electrochemical process, where all components are taken in a single solution in the electrochemical cell.

  7. Poly(BCB)/Au-nanoparticles hybrid film modified electrode: Preparation, characterization and its application as a non-enzymatic sensor

    International Nuclear Information System (INIS)

    Kumar, S. Ashok; Wang, Sea-Fue; Chang, Yu-Tsern

    2010-01-01

    We report electrochemical preparation and characterization of poly-brilliant cresyl blue (Poly(BCB))/gold nanoparticles (Au-NPs) modified electrode. The Poly(BCB)/Au-NPs modified electrode has been used as an electrochemical sensor for the detection of hydrogen peroxide (H 2 O 2 ) at lower potential (- 0.2 V). The Poly(BCB)/Au-NPs film was characterized by scanning electron microscopy, Uv-visible spectroscopy (Uv-vis) and cyclic voltammetry. We have observed that, Au-NPs attached glassy carbon electrode (Au-NPs/GCE) significantly enhanced the polymerization of BCB compared to bare GCE. The Poly(BCB) film was irreversibly attached onto the Au-NPs modified electrode, the resulting hybrid film modified electrode was electrochemically active in the pH range from 2 to 11. Attachment of Poly(BCB)/Au-NPs hybrid film on the electrode surface was confirmed by Uv-vis spectra. In addition, electrocatalytic properties of the Poly(BCB)/Au-NPs/GCE towards reduction of H 2 O 2 have been investigated, and it was found that the sensitivity, reduction potential as well as the corresponding detection limit were improved as compared to the voltammetric response of the Poly(BCB)/GCE and Au-NPs/GCE. Based on this study, a non-enzymatic electrochemical sensor for the determination of H 2 O 2 has been reported. Moreover, analysis of commercial H 2 O 2 samples was performed using the proposed method and satisfactory results were obtained.

  8. Non-Enzymatic Decomposition of Collagen Fibers by a Biglycan Antibody and a Plausible Mechanism for Rheumatoid Arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Antipova, Olga; Orgel, Joseph P.R.O. (IIT)

    2013-04-08

    Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory and destructive joint disorder that affects tens of millions of people worldwide. Normal healthy joints maintain a balance between the synthesis of extracellular matrix (ECM) molecules and the proteolytic degradation of damaged ones. In the case of RA, this balance is shifted toward matrix destruction due to increased production of cleavage enzymes and the presence of (autoimmune) immunoglobulins resulting from an inflammation induced immune response. Herein we demonstrate that a polyclonal antibody against the proteoglycan biglycan (BG) causes tissue destruction that may be analogous to that of RA affected tissues. The effect of the antibody is more potent than harsh chemical and/or enzymatic treatments designed to mimic arthritis-like fibril de-polymerization. In RA cases, the immune response to inflammation causes synovial fibroblasts, monocytes and macrophages to produce cytokines and secrete matrix remodeling enzymes, whereas B cells are stimulated to produce immunoglobulins. The specific antigen that causes the RA immune response has not yet been identified, although possible candidates have been proposed, including collagen types I and II, and proteoglycans (PG's) such as biglycan. We speculate that the initiation of RA associated tissue destruction in vivo may involve a similar non-enzymatic decomposition of collagen fibrils via the immunoglobulins themselves that we observe here ex vivo.

  9. Beneficial Effects of Lemon Balm Leaf Extract on In Vitro Glycation of Proteins, Arterial Stiffness, and Skin Elasticity in Healthy Adults.

    Science.gov (United States)

    Yui, Shintaro; Fujiwara, Suzuka; Harada, Katsuhisa; Motoike-Hamura, Mahoko; Sakai, Masashi; Matsubara, Satoshi; Miyazaki, Kouji

    2017-01-01

    Glycation, a non-enzymatic glycosylation of proteins, induces tissue damage in association with various diseases and aging phenomena. Pentosidine, an advanced glycation end product, is involved in aging phenomena such as tissue stiffness. In this study, we aimed to find a potent anti-glycation food material and to verify its health benefits by clinical trial. From among 681 hot water plant extracts, lemon balm (Melissa officinalis; LB) leaf extract was selected and revealed to have more potent inhibitory activity for pentosidine formation than a representative anti-glycation agent, aminoguanidine. Rosmarinic acid (RA), a typical polyphenol in Lamiaceae plants, was identified as a major active component in LB extract (LBE). Furthermore, LBE or RA dose-dependently suppressed glycation-associated reactions such as increased fluorescence, yellowing of collagen fiber sheets, and degeneration of the fibrous structure of elastin fiber sheets. An open-label, parallel-group comparative trial was conducted in 28 healthy Japanese subjects aged 31-65 y who consumed LB tea (LB group) or barley tea (Control group) for 6 wk. The LB group showed significant reductions in brachial-ankle pulse wave velocity, reflecting arterial stiffness, and b* (yellow) color values in forearm skin compared with the Control group. A gender-stratified analysis revealed that cheek skin elasticity was significantly improved in the LB group compared with the Control group only in female subjects. It is concluded that the hot water extract of LB leaf has the potential to provide health benefits with regard to glycation-associated tissue damage in blood vessels and skin of healthy adults.

  10. One-step preparation of silver–polyaniline nanotube composite for non-enzymatic hydrogen peroxide detection

    Energy Technology Data Exchange (ETDEWEB)

    Lorestani, Farnaz, E-mail: Farnaz.lorestani@siswa.um.edu.my; Shahnavaz, Zohreh; Nia, Pooria Moozarm; Alias, Y.; Manan, Ninie S.A., E-mail: niniemanan@um.edu.my

    2015-08-30

    Graphical abstract: - Highlights: • Silver nanoparticle-decorated polyaniline nanotube composites (AgNPs–PANINTs) have been fabricated through a one step modified method without adding any extra acids, template and surface modifier. • The sensor showed excellent selectivity, reproducibility, and stability properties. • The AgNPs–PANINTs composite that prepared with silver ammonia solution (Ag(NH{sub 3}){sub 2}OH) exhibits better electrochemical performance than the AgNPs–PANINTs composite that was prepared with silver nitrite (AgNO{sub 3}) due to smaller size and higher surface area of silver nanoparticle (AgNPs) in the composite. • The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of PANI to Ag(NH{sub 3}){sub 2}OH (0.04 M). - Abstract: A modified glassy carbon electrode with silver nanoparticles–polyaniline nanotubes (AgNPs–PANINTs) composite is used as a non-enzymatic nanobiosensor for detecting hydrogen peroxide (H{sub 2}O{sub 2}). The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of PANI to Ag(NH{sub 3}){sub 2}OH (0.04 M). Field emission scanning electron microscope images and their size distribution diagrams indicated that using the silver ammonia complex instead of silver nitrate caused uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution in the composite. The corresponding calibration curve for the current response showed a linear detection range of 0.1–90 mM (R{sup 2} = 0.9986), while the limit of detection was estimated to be 0.2 μM at the signal to noise ratio of 3.

  11. Construction of an ultrasensitive non-enzymatic sensor to investigate the dynamic process of superoxide anion release from living cells.

    Science.gov (United States)

    Wei, Hongwei; Shang, Tianyi; Wu, Tiaodi; Liu, Guoan; Ding, Lan; Liu, Xiuhui

    2018-02-15

    In this work, a novel non-enzymatic superoxide anion (O 2 • - ) sensor was constructed based on Ag nanoparticles (NPs) / poly (amidoamine) (PAMAM) dendrimers and used to investigate the dynamic process of O 2 • - release from living cells. The AgNPs/PAMAM nanohybrids were characterized by transmission electron microscopy (TEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The fabricated electrode exhibited excellent catalytic activity toward the reaction of O 2 • - with a super low detection limit (LOD) of 2.530 × 10 -13 M (S/N = 3) and wide linear range of 8 orders of magnitude. It could fulfill the requirement of real-time measurement O 2 • - released from living cells. Furthermore, zymosan was chosen as the stimulant to induce O 2 • - generation from cancer cells (rat adrenal medulla pheochromocytoma cell (PC12)). The electrochemical experiment results indicated that the levels of intracellular O 2 • - depended on the amount of Zymosan. A large amount of O 2 • - generated in the living cells by added heavy stimulant could damage cells seriously. More importantly, a vitro simulation experiment confirmed the role of superoxide dismutase (SOD) for the first time because it could maintain the O 2 • - concentration at a normal physiological range. These findings are of great significance for evaluating the metabolic processes of O 2 • - in the biological system, and this work has the tremendous potential application in clinical diagnostics to assess oxidative stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. A non-enzymatic function of Golgi glycosyltransferases: mediation of Golgi fragmentation by interaction with non-muscle myosin IIA.

    Science.gov (United States)

    Petrosyan, Armen; Cheng, Pi-Wan

    2013-06-01

    The Golgi apparatus undergoes morphological changes under stress or malignant transformation, but the precise mechanisms are not known. We recently showed that non-muscle myosin IIA (NMIIA) binds to the cytoplasmic tail of Core 2 N-acetylglucosaminyltransferase mucus-type (C2GnT-M) and transports it to the endoplasmic reticulum for recycling. Here, we report that Golgi fragmentation induced by brefeldin A (BFA) or coatomer protein (β-COP) knockdown (KD) in Panc1-bC2GnT-M (c-Myc) cells is accompanied by the increased association of NMIIA with C2GnT-M and its degradation by proteasomes. Golgi fragmentation is prevented by inhibition or KD of NMIIA. Using multiple approaches, we have shown that the speed of BFA-induced Golgi fragmentation is positively correlated with the levels of this enzyme in the Golgi. The observation is reproduced in LNCaP cells which express high levels of two endogenous glycosyltransferases--C2GnT-L and β-galactoside α2,3 sialyltransferase 1. NMIIA is found to form complexes with these two enzymes but not Golgi matrix proteins. The KD of both enzymes or the prevention of Golgi glycosyltransferases from exiting endoplasmic reticulum reduced Golgi-associated NMIIA and decreased the BFA-induced fragmentation. Interestingly, the fragmented Golgi detected in colon cancer HT-29 cells can be restored to a compact morphology after inhibition or KD of NMIIA. The Golgi disorganization induced by the microtubule or actin destructive agent is NMIIA-independent and does not affect the levels of glycosyltransferases. We conclude that NMIIA interacts with Golgi residential but not matrix proteins, and this interaction is responsible for Golgi fragmentation induced by β-COP KD or BFA treatment. This is a novel non-enzymatic function of Golgi glycosyltransferases.

  13. Non-enzymatic antioxidant capacity (NEAC) estimated by two different dietary assessment methods and its relationship with NEAC plasma levels.

    Science.gov (United States)

    Carrión-García, Cayetano Javier; Guerra-Hernández, Eduardo J; García-Villanova, Belén; Molina-Montes, Esther

    2017-06-01

    We aimed to quantify and compare dietary non-enzymatic antioxidant capacity (NEAC), estimated using two dietary assessment methods, and to explore its relationship with plasma NEAC. Fifty healthy subjects volunteer to participate in this study. Two dietary assessment methods [a food frequency questionnaire (FFQ) and a 24-hour recall (24-HR)] were used to collect dietary information. Dietary NEAC, including oxygen radical absorbance capacity (ORAC), total polyphenols, ferric-reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity, was estimated using several data sources of NEAC content in food. NEAC status was measured in fasting blood samples using the same assays. We performed nonparametric Spearman's correlation analysis between pairs of dietary NEAC (FFQ and 24-HR) and diet-plasma NEAC, with and without the contribution of coffee's NEAC. Partial correlation analysis was used to estimate correlations regardless of variables potentially influencing these relationships. FFQ-based NEAC and 24-HR-based NEAC were moderately correlated, with correlation coefficients ranging from 0.54 to 0.71, after controlling for energy intake, age and sex. Statistically significant positive correlations were found for dietary FRAP, either derived from the FFQ or the 24-HR, with plasma FRAP (r ~ 0.30). This weak, albeit statistically significant, correlation for FRAP was mostly present in the fruits and vegetables food groups. Plasma ORAC without proteins and 24-HR-based total ORAC were also positively correlated (r = 0.35). The relationship between dietary NEAC and plasma FRAP and ORAC suggests the dietary NEAC may reflect antioxidant status despite its weak in vivo potential, supporting further its use in oxidative stress-related disease epidemiology.

  14. Vertically grown zinc oxide nanorods functionalized with ferric oxide for in vivo and non-enzymatic glucose detection

    Science.gov (United States)

    Marie, Mohammed; Manoharan, Anishkumar; Kuchuk, Andrian; Ang, Simon; Manasreh, M. O.

    2018-03-01

    An enzyme-free glucose sensor based on vertically grown zinc oxide nanorods (NRs) functionalized with ferric oxide (Fe2O3) is investigated. The well-aligned and high density ZnO NRs were synthesized on an FTO/glass substrate by a sol-gel and hydrothermal growth method. A dip-coating technique was utilized to modify the surface of the as-grown ZnO NRs with Fe2O3. The immobilized surface was coated with a layer of nafion membrane. The fabricated glucose sensor was characterized amperometrically at room temperature using three electrodes stationed in the phosphate buffer solution, where ZnO NRs/Fe2O3/nafion membrane was the sensing or working electrode, and platinum plate and silver/silver chloride were used as the counter and reference electrodes, respectively. The proposed non-enzymatic and modified glucose sensor exhibited a high sensitivity in the order of 0.052 μA cm-2 (mg/dL)-1, a lower detection limit of around 0.95 mmol L-1, a sharp and fast response time of ˜1 s, and a linear response to changes in glucose concentrations from 100-400 mg dL-1. The linear amperometric response of the sensor covers the physiological and clinical interest of glucose levels for diabetic patients. The device continues to function accurately after multiple measurements with a good reproducibility. The proposed glucose sensor is expected to be used clinically for in vivo monitoring of glucose.

  15. A non-enzymatic amperometric hydrogen peroxide sensor based on iron nanoparticles decorated reduced graphene oxide nanocomposite.

    Science.gov (United States)

    Amanulla, Baishnisha; Palanisamy, Selvakumar; Chen, Shen-Ming; Velusamy, Vijayalakshmi; Chiu, Te-Wei; Chen, Tse-Wei; Ramaraj, Sayee Kannan

    2017-02-01

    A simple and facile green process was used for the synthesis of iron nanoparticles (FeNPs) decorated reduced graphene oxide (rGO) nanocomposite by using Ipomoea pes-tigridis leaf extract as a reducing and stabilizing agent. The as-prepared rGO/FeNPs nanocomposite was characterized by transmission electron microscopy, X-ray spectroscopy and Fourier transform infrared spectroscopy. The nanocomposite was further modified on the glassy carbon electrode and used for non-enzymatic sensing of hydrogen peroxide (H 2 O 2 ). Cyclic voltammetry results reveal that rGO/FeNPs nanocomposite has excellent electro-reduction behavior to H 2 O 2 when compared to the response of FeNPs and rGO modified electrodes. Furthermore, the nanocomposite modified electrode shows 9 and 6 folds enhanced reduction current response to H 2 O 2 than that of rGO and FeNPs modified electrodes. Amperometric method was further used to quantify the H 2 O 2 using rGO/FeNPs nanocomposite, and the response was linear over the concentration ranging from 0.1μM to 2.15mM. The detection limit and sensitivity of the sensor were estimated as 0.056μM and 0.2085μAμM -1 cm -2 , respectively. The fabricated sensor also utilized for detection of H 2 O 2 in the presence of potentially active interfering species, and found high selectivity towards H 2 O 2 . Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Enzymatic and non-enzymatic antioxidant potentials of Chlorella vulgaris grown in effluent of a confectionery industry.

    Science.gov (United States)

    Kumar, R Ranjith; Rao, P Hanumantha; Subramanian, V V; Sivasubramanian, V

    2014-02-01

    Enzymatic and non-enzymatic antioxidant potentials of Chlorella vulgaris have gained considerable importance in recent decades. C. vulgaris strain highly tolerant to extreme pH variations was isolated and mass-cultivated in the wastewater from a confectionery industry. C.vulgaris showed better growth in wastewater than in improvised CFTRI medium. The microalgal biomass was then screened for the following antioxidants: peroxidase, superoxide dismutase, polyphenol oxidase, glutathione peroxidase, chlorophyll a, ascorbic acid, α-tocopherol and reduced glutathione. The total polyphenol content of the strain was also studied. The strain showed a high degree of enzymatic antioxidant activity (0.195 × 10(-5) ± 0.0072 units/cell peroxidase, 0.04125 × 10(-5) ± 0.001 units/cell superoxide dismutase, 0.2625 × 10(-5) ± 0.003 units/cell polyphenol oxidase and 0.025 × 10(-5) ± 0.003 glutathione peroxidase). The microalgal biomass also showed, per milligram weight, 0.2182 ± 0.005 μg of ascorbic acid, 0.00264 ± 0.001 μg of α-tocopherol and 0.07916 ± 0.004 μg of reduced glutathione. These results represent the possibility of using C. vulgaris grown in confectionery industry wastewater as a source of nutritious supplement, which is highly promising in terms of both economic and nutritional point of view.

  17. Deamidation of asparagine and glutamine residues in proteins and peptides: structural determinants and analytical methodology

    NARCIS (Netherlands)

    Bischoff, Rainer; Kolbe, H.V.

    1994-01-01

    Non-enzymatic deamidation of asparagine and glutamine residues in proteins and peptides are reviewed by first outlining the well-described reaction mechanism involving cyclic imide intermediates, followed by a discussion of structural features which influence the reaction rate. The second and major

  18. New parameters for evaluating the quality of commercial krill oil capsules from the aspect of lipid oxidation and non-enzymatic browning reactions

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Bruheim, Inge; Jacobsen, Charlotte

    2015-01-01

    , and their alkyl derivatives, sulphur and amino compounds). The data of chemical composition of krill oil were correlated well with those from volatile measurement. Through investigating volatile profile, new insights into the lipid oxidation and non-enzymatic browning reactions in krill oil were obtained...... different commercial krill oil capsules through parameters such as: investigation of chemical compositions (bioactive compounds such as phospholipids, n-3 polyunsaturated fatty acids, antioxidants), hydrophobic pyrroles, and volatile profiles (lipid and Strecker-derived volatiles, pyridines, pyrazines...... provides new parameters to differentiate the quality of krill oil through the measurement of bioactive compounds and hydrophobic pyrroles in krill oil, and investigation of volatile profiles of krill oil from the aspect of lipid oxidation and non-enzymatic browning reactions....

  19. Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

    Energy Technology Data Exchange (ETDEWEB)

    Tajabadi, M.T. [University Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Sookhakian, M., E-mail: m.sokhakian@gmail.com [University Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea (Korea, Republic of); Zalnezhad, E., E-mail: erfan@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea (Korea, Republic of); Yoon, G.H. [Department of Mechanical Convergence Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea (Korea, Republic of); Hamouda, A.M.S. [Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, 2713, Doha (Qatar); Azarang, Majid [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Basirun, W.J. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Institute of Nanotechnology & Catalysis Research, Institute of Postgraduate Studies, University Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Y., E-mail: yatimah70@um.edu.my [University Malaya Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2016-11-15

    Highlights: • Nitrogen doped graphene with different thickness by electrophoretic deposition. • The conductivity of N-graphene layer depends on the tickness. • Support of platinum shows efficient electrocatalytic performance for biosensor. • CV curves and amperometric responses improved and optimized in the presence of N-graphene. - Abstract: An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900 °C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H{sub 2}O{sub 2}). The behaviors of the hybrid electrodes towards H{sub 2}O{sub 2} reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05 mg ml{sup −1} N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H{sub 2}O{sub 2} detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

  20. Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

    International Nuclear Information System (INIS)

    Tajabadi, M.T.; Sookhakian, M.; Zalnezhad, E.; Yoon, G.H.; Hamouda, A.M.S.; Azarang, Majid; Basirun, W.J.; Alias, Y.

    2016-01-01

    Highlights: • Nitrogen doped graphene with different thickness by electrophoretic deposition. • The conductivity of N-graphene layer depends on the tickness. • Support of platinum shows efficient electrocatalytic performance for biosensor. • CV curves and amperometric responses improved and optimized in the presence of N-graphene. - Abstract: An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900 °C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H 2 O 2 ). The behaviors of the hybrid electrodes towards H 2 O 2 reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05 mg ml −1 N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H 2 O 2 detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

  1. Biological variability of glycated hemoglobin.

    Science.gov (United States)

    Braga, Federica; Dolci, Alberto; Mosca, Andrea; Panteghini, Mauro

    2010-11-11

    The measurement of glycated hemoglobin (HbA(1c)) has a pivotal role in monitoring glycemic state in diabetic patients. Furthermore, the American Diabetes Association has recently recommended the use of HbA(1c) for diabetes diagnosis, but a clear definition of the clinically allowable measurement error is still lacking. Information on biological variability of the analyte can be used to achieve this goal. We systematically reviewed the published studies on the biological variation of HbA(1c) to check consistency of available data in order to accurately define analytical goals. The nine recruited studies were limited by choice of analytic methodology, population selection, protocol application and statistical analyses. There is an urgent need to determine biological variability of HbA(1c) using a specific and traceable assay, appropriate protocol and appropriate statistical evaluation of data. 2010 Elsevier B.V. All rights reserved.

  2. Technical Report for a Study on the Mechanism and Control of Non-Enzymatic Browning Reaction in Gamma-Irradiated Food

    International Nuclear Information System (INIS)

    Byun, Myung Woo; Lee, Ju Woon; Kim, Jae Hun

    2007-01-01

    Gamma irradiation leads to a non-enzymatic browning reaction (carbonyl -amine reaction) in an aqueous system similar to those induced in a heated one. This reaction may influence the changes of the color in irradiated foods. The intensity of the reaction was dependent on the type of the sugar, if the occurrence is by irradiation or by heating. There was a difference in the browning reaction between irradiation and heating. Although no browning was observed in the heated solution of the non-reducing sugar, the formation of colored products was observed in the irradiated sucrose-lysine solution. It could be explained on the basis that irradiation promotes the breakdown of the glycosidic linkages of the disaccharide, sucrose and the produce of a reducing power. The high molecular weight melanoidin (> MW 12,000-14,000 Da) was produced by gamma irradiation from the non-enzymatic browning reaction between glucose and glycine. The structure of melanoidin was similar to melanodin from heat processing. The results suggested that gamma-irradiation occurred the non-enzymatic browning reaction that is similar the reaction by heat processing. Non-enzymatic browning reaction during gamma-irradiation processing was greatly influenced by pH and medium of reaction system. The brown color development of irradiated sugar solutions with and without glycine is more increased in buffer system especially with alkaline pH than DDW. When food is irradiated, off-color such as browning can be produced due to the non-enzymatic browning reaction and it is influenced by other ions and/or pH of system. This suggests that the browning of irradiated food might be retarded by lowering the pH of the system. Gamma-irradiation produce the free radical and the radiolysis products of sugar and glycine and then they may be condensed to colored products during post-irradiation. However, when the food is irradiated in frozen state, the production of free radical and radiolysis product is inhibited and it

  3. Technical Report for a Study on the Mechanism and Control of Non-Enzymatic Browning Reaction in Gamma-Irradiated Food

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Myung Woo; Lee, Ju Woon; Kim, Jae Hun

    2007-01-15

    Gamma irradiation leads to a non-enzymatic browning reaction (carbonyl -amine reaction) in an aqueous system similar to those induced in a heated one. This reaction may influence the changes of the color in irradiated foods. The intensity of the reaction was dependent on the type of the sugar, if the occurrence is by irradiation or by heating. There was a difference in the browning reaction between irradiation and heating. Although no browning was observed in the heated solution of the non-reducing sugar, the formation of colored products was observed in the irradiated sucrose-lysine solution. It could be explained on the basis that irradiation promotes the breakdown of the glycosidic linkages of the disaccharide, sucrose and the produce of a reducing power. The high molecular weight melanoidin (> MW 12,000-14,000 Da) was produced by gamma irradiation from the non-enzymatic browning reaction between glucose and glycine. The structure of melanoidin was similar to melanodin from heat processing. The results suggested that gamma-irradiation occurred the non-enzymatic browning reaction that is similar the reaction by heat processing. Non-enzymatic browning reaction during gamma-irradiation processing was greatly influenced by pH and medium of reaction system. The brown color development of irradiated sugar solutions with and without glycine is more increased in buffer system especially with alkaline pH than DDW. When food is irradiated, off-color such as browning can be produced due to the non-enzymatic browning reaction and it is influenced by other ions and/or pH of system. This suggests that the browning of irradiated food might be retarded by lowering the pH of the system. Gamma-irradiation produce the free radical and the radiolysis products of sugar and glycine and then they may be condensed to colored products during post-irradiation. However, when the food is irradiated in frozen state, the production of free radical and radiolysis product is inhibited and it

  4. Non-enzymatic modifications in metallothioneins connected to lipid membrane damages: structural and biomimetic studies under reductive radical stress.

    Science.gov (United States)

    Torreggiani, Armida; Chatgilialoglu, Chryssostomos; Ferreri, Carla; Melchiorre, Michele; Atrian, Silvia; Capdevila, Merce'

    2013-10-30

    Metallothioneins (MTs) are small cysteine-rich proteins with the ability to coordinate heavy metal atoms through metal-thiolate bonds, which are widely distributed among the animal and plant kingdoms. Multifunctional roles for MTs have been proposed, including their ability to scavenger various radicals and reactive oxygen species. In the present article we summarize available information of four MT polypeptides from different organisms, forming metal complexes with Zn(II), Cd(II) or Cu (I) ions. Non-enzymatic modifications of MTs under ionizing radiations and their consequences on the lipidic membrane compartment were studied by Raman spectroscopy and a biomimetic model, respectively. The latter is based on liposome technology and allows to measure the trans unsaturated fatty acid content as a result of reductive radical stress on MTs. The effect of radical stress on the cell metabolism and functions is a very active field of research connecting various disciplines in life sciences. In this contest tandem radical damage has been the subject of recent investigations that pointed out its harmfulness in the general scenario of establishing the consequences of radical stress. By using biomimetic models of tandem damage we have for the first time tested the capability of metallothioneins (MTs), small metalloproteins rich of Cys residues, to damage another cell compartment like lipid membranes when they are undergone to reductive radical stress. The connection of MT reactivity with membrane lipid transformation can give a contribution to the puzzling context of radical stress occurring to biomolecules and the role as biological signaling. To this purpose, MT polypeptides from different organisms, exhibiting different sequence peculiarities, have been analyzed here. The spectroscopic analysis of these systems has allowed to identify modifications affecting metal-thiolate clusters, cystines, and Met residues, acting as efficient interceptors of reducing radical species

  5. The ethylene glycol template assisted hydrothermal synthesis of Co{sub 3}O{sub 4} nanowires; structural characterization and their application as glucose non-enzymatic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Khun, K., E-mail: kimleang.khun@liu.se [Department of Science and Technology, Linköping University, SE-60174 Norrköping (Sweden); Ibupoto, Z.H. [Dr M.A. Kazi Institute of Chemistry, University of Sindh Jamshoro, Sindh Jamshoro (Pakistan); Liu, X. [Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping (Sweden); Beni, V. [Biosensors and Biolelectronics Centre, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping (Sweden); Willander, M. [Department of Science and Technology, Linköping University, SE-60174 Norrköping (Sweden)

    2015-04-15

    Highlights: • Ethylene glycol assisted Co{sub 3}O{sub 4} nanowires were synthesized by hydrothermal method. • The grown Co{sub 3}O{sub 4} nanowires were used for sensitive non-enzymatic glucose sensor. • The proposed glucose sensor shows a wide linear range with fast response. • The Co{sub 3}O{sub 4} modified electrode is a highly specific enzyme-less glucose sensor. - Abstract: In the work reported herein the ethylene glycol template assisted hydrothermal synthesis, onto Au substrate, of thin and highly dense cobalt oxide (Co{sub 3}O{sub 4}) nanowires and their characterization and their application for non-enzymatic glucose sensing are reported. The structure and composition of Co{sub 3}O{sub 4} nanowires have been fully characterized using scanning electron microscopy, X-ray diffraction, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The synthesized Co{sub 3}O{sub 4} nanowires resulted to have high purity and showed diameter of approximately 10 nm. The prepared Co{sub 3}O{sub 4} nanowires coated gold electrodes were applied to the non-enzymatic detection of glucose. The developed sensor showed high sensitivity (4.58 × 10{sup 1} μA mM{sup −1} cm{sup −2}), a wide linear range of concentration (1.00 × 10{sup −4}–1.2 × 10{sup 1} mM) and a detection limit of 2.65 × 10{sup −5} mM. The developed glucose sensor has also shown to be very stable and selective over interferents such as uric acid and ascorbic acid. Furthermore, the proposed fabrication process was shown to be highly reproducible response (over nine electrodes)

  6. Non-enzymatic hydrogen peroxide biosensor based on rose-shaped FeMoO{sub 4} nanostructures produced by convenient microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongying, E-mail: liuhongying@hdu.edu.cn [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Zhejiang, Hangzhou 310018 (China); Gu, Chunchuan [Department of Clinical Laboratory, Hangzhou Cancer Hospital, Zhejiang, Hangzhou 310002 (China); Li, Dujuan; Zhang, Mingzhen [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Zhejiang, Hangzhou 310018 (China)

    2015-04-15

    Graphical abstract: A non-enzymatic H{sub 2}O{sub 2} sensor with high selectivity and sensitivity based on rose-shaped FeMoO{sub 4} synthesized by the convenient microwave-assisted hydrothermal method, was fabricated. - Highlights: • Rose-shaped FeMoO{sub 4} is synthesized within 10 min via microwave-assisted hydrothermal approach. • Non-enzymatic hydrogen peroxide biosensor based on FeMoO{sub 4} nanomaterials is fabricated. • The biosensor exhibits good performance. - Abstract: In this work, we demonstrated a simple, rapid and reliable microwave-assisted hydrothermal approach to synthesize the uniform rose-shaped FeMoO{sub 4} within 10 min. The morphologies of the synthesized materials were characterized by X-ray powder diffraction and scanning electron microscopy. Moreover, a non-enzymatic amperometric sensor for the detection of hydrogen peroxide (H{sub 2}O{sub 2}) was fabricated on the basis of the FeMoO{sub 4} as electrocatalysis. The resulting FeMoO{sub 4} exhibited high sensitivity and good stability for the detection of H{sub 2}O{sub 2}, which may be attributed to the rose-shaped structure of the material and the catalytic property of FeMoO{sub 4}. Amperometric response showed that the modified electrode had a good response for H{sub 2}O{sub 2} with a linear range from 1 μM to 1.6 mM, a detection limit of 0.5 μM (S/N = 3), high selectivity and short response time. Additionally, good recoveries of analytes in real milk samples confirm the reliability of the prepared sensor in practical applications.

  7. Non-enzymatic glycosylation of a type I collagen matrix: effects on osteoblastic development and oxidative stress

    Directory of Open Access Journals (Sweden)

    Barrio Daniel A

    2001-08-01

    Full Text Available Abstract Background The tissue accumulation of protein-bound advanced glycation endproducts (AGE may be involved in the etiology of diabetic chronic complications, including osteopenia. The aim of this study was to investigate the effect of an AGE-modified type I collagen substratum on the adhesion, spreading, proliferation and differentiation of rat osteosarcoma UMR106 and mouse non-transformed MC3T3E1 osteoblastic cells. We also studied the role of reactive oxygen species (ROS and nitric oxide synthase (NOS expression on these AGE-collagen mediated effects. Results AGE-collagen decreased the adhesion of UMR106 cells, but had no effect on the attachment of MC3T3E1 cells. In the UMR106 cell line, AGE-collagen also inhibited cellular proliferation, spreading and alkaline phosphatase (ALP activity. In preosteoblastic MC3T3E1 cells (24-hour culture, proliferation and spreading were significantly increased by AGE-collagen. After one week of culture (differentiated MC3T3E1 osteoblasts AGE-collagen inhibited ALP activity, but had no effect on cell number. In mineralizing MC3T3E1 cells (3-week culture AGE-collagen induced a decrease in the number of surviving cells and of extracellular nodules of mineralization, without modifying their ALP activity. Intracellular ROS production, measured after a 48-hour culture, was decreased by AGE-collagen in MC3T3E1 cells, but was increased by AGE-collagen in UMR106 cells. After a 24-hour culture, AGE-collagen increased the expression of endothelial and inducible NOS, in both osteoblastic cell lines. Conclusions These results suggest that the accumulation of AGE on bone extracellular matrix could regulate the proliferation and differentiation of osteoblastic cells. These effects appear to depend on the stage of osteoblastic development, and possibly involve the modulation of NOS expression and intracellular ROS pathways.

  8. Impact of primary amine group from aminophospholipids and amino acids on marine phospholipids stability: Non-enzymatic browning and lipid oxidation

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Nielsen, Nina Skall; Baron, Caroline P.

    2013-01-01

    The main objective of this study was to investigate the oxidative stability and non-enzymatic browning reactions of marine PL in the presence or in the absence of primary amine group from aminophospholipids and amino acids. Marine phospholipids liposomal dispersions were prepared from two authent...... the formation of pyrroles, generated Strecker derived volatiles, decreased the YI development and lowered lipid oxidation. The lower degree of lipid oxidation in liposomal dispersions containing amino acids might be attributed to antioxidative properties of pyrroles or amino acids....

  9. Phytochemicals Against Advanced Glycation End Products (AGEs) and the Receptor System.

    Science.gov (United States)

    Yamagishi, Sho-Ichi; Matsui, Takanori; Ishibashi, Yuji; Isami, Fumiyuki; Abe, Yumi; Sakaguchi, Tatsuya; Higashimoto, Yuichiro

    2017-01-01

    Reducing sugars can react non-enzymatically with amino groups of proteins and lipids to form irreversibly cross-linked macroprotein derivatives called as advanced glycation end products (AGEs). Cross-linking modification of extracellular matrix proteins by AGEs deteriorate their tertiary structural integrity and function, contributing to aging-related organ damage and diabetes-associated complications, such as cardiovascular disease (CVD). Moreover, engagement of receptor for AGEs, RAGE with the ligands evoke oxidative stress generation and inflammatory, thrombotic and fibrotic reactions in various kinds of tissues, further exacerbating the deleterious effects of AGEs on multiple organ systems. So the AGE-RAGE axis is a novel therapeutic target for numerous devastating disorders. Several observational studies have shown the association of dietary consumption of fruits and vegetables with the reduced risk of CVD in a general population. Although beneficial effects of fruits and vegetables against CVD could mainly be ascribed to its anti-oxidative properties, blockade of the AGERAGE axis by phytochemicals may also contribute to cardiovascular event protection. Therefore, in this review, we focus on 4 phytochemicals (quercetin, sulforaphane, iridoids, and curcumin) and summarize their effects on AGE formation as well as RAGE-mediated signaling pathway in various cell types and organs, including endothelial cells, vessels, and heart. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Advanced Glycation End Products: Link between Diet and Ovulatory Dysfunction in PCOS?

    Directory of Open Access Journals (Sweden)

    Deepika Garg

    2015-12-01

    Full Text Available PCOS is the most common cause of anovulation in reproductive-aged women with 70% experiencing ovulatory problems. Advanced glycation end products are highly reactive molecules that are formed by non-enzymatic reactions of sugars with proteins, nucleic acids and lipids. AGEs are also present in a variety of diet where substantial increase in AGEs can result due to thermal processing and modifications of food. Elevation in bodily AGEs, produced endogenously or absorbed exogenously from high-AGE diets, is further exaggerated in women with PCOS and is associated with ovulatory dysfunction. Additionally, increased expression of AGEs as pro-inflammatory receptors in the ovarian tissue has been observed in women with PCOS. In this review, we summarize the role of dietary AGEs as mediators of metabolic and reproductive alterations in PCOS. Once a mechanistic understanding of the relationship between AGEs and anovulation is established, there is a promise that such knowledge will contribute to the subsequent development of targeted pharmacological therapies that will treat anovulation and improve ovarian health in women with PCOS.

  11. Advanced Glycation End Products: Link between Diet and Ovulatory Dysfunction in PCOS?

    Science.gov (United States)

    Garg, Deepika; Merhi, Zaher

    2015-12-04

    PCOS is the most common cause of anovulation in reproductive-aged women with 70% experiencing ovulatory problems. Advanced glycation end products are highly reactive molecules that are formed by non-enzymatic reactions of sugars with proteins, nucleic acids and lipids. AGEs are also present in a variety of diet where substantial increase in AGEs can result due to thermal processing and modifications of food. Elevation in bodily AGEs, produced endogenously or absorbed exogenously from high-AGE diets, is further exaggerated in women with PCOS and is associated with ovulatory dysfunction. Additionally, increased expression of AGEs as pro-inflammatory receptors in the ovarian tissue has been observed in women with PCOS. In this review, we summarize the role of dietary AGEs as mediators of metabolic and reproductive alterations in PCOS. Once a mechanistic understanding of the relationship between AGEs and anovulation is established, there is a promise that such knowledge will contribute to the subsequent development of targeted pharmacological therapies that will treat anovulation and improve ovarian health in women with PCOS.

  12. Phlorotannins from Brown Algae: inhibition of advanced glycation end products formation in high glucose induced Caenorhabditis elegans.

    Science.gov (United States)

    Shakambari, Ganeshan; Ashokkumar, Balasubramaniem; Varalakshmi, Perumal

    2015-06-01

    Advanced Glycation End products (AGE) generated in a non enzymatic protein glycation process are frequently associated with diabetes, aging and other chronic diseases. Here, we explored the protective effect of phlorotannins from brown algae Padina pavonica, Sargassum polycystum and Turbinaria ornata against AGEs formation. Phlorotannins were extracted from brown algae with methanol and its purity was analyzed by TLC and RP-HPLC-DAD. Twenty five grams of P. pavonica, S. polycystum, T. ornata yielded 27.6 ± 0.8 μg/ml, 37.7 μg/ml and 37.1 ± 0.74 μg/ml of phloroglucinol equivalent of phlorotannins, respectively. Antioxidant potentials were examined through DPPH assay and their IC50 values were P. pavonica (30.12 ± 0.99 μg), S. polycystum (40.9 ± 1.2 μg) and T. ornata (22.9 ± 1.3 μg), which was comparatively lesser than the control ascorbic acid (46 ± 0.2 μg). Further, anti-AGE activity was examined in vitro by BSA-glucose assay with the extracted phlorotannins of brown algae (P. pavonica, 15.16 ± 0.26 μg/ml; S. polycystum, 35.245 ± 2.3 μg/ml; T. ornata, 22.7 ± 0.3 μg/ml), which revealed the required concentration to inhibit 50% of albumin glycation (IC50) were lower for extracts than controls (phloroglucinol, 222.33 ± 4.9 μg/ml; thiamine, 263 μg/ml). Furthermore, brown algal extracts containing phlorotannins (100 μl) exhibited protective effects against AGE formation in vivo in C. elegans with induced hyperglycemia.

  13. A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Zhonghua, E-mail: xzh@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); He, Nan [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Rao, Honghong [College of Chemistry and Chemical Engineering, Lanzhou City University, Lanzhou, 730070 (China); Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Lu, Xiaoquan, E-mail: luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2017-02-28

    Highlights: • A sensitive non-enzymatic glucose sensor was explored by using a facile and green strategy. • Well dispersed and uniform NiHCF nanoparticles can be effectively produced by the introduction of electrochemical reduction graphene oxide films. • Metal hexacyanoferrate as a potential electron mediator was proposed and applied into non-enzymatic sensing. - Abstract: Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

  14. Moderate O3/O2therapy enhances enzymatic and non-enzymatic antioxidant in brain and cochlear that protects noise-induced hearing loss.

    Science.gov (United States)

    Nasezadeh, Parvaneh; Shahi, Farshad; Fridoni, Mohammadjavad; Seydi, Enayatollah; Izadi, Morteza; Salimi, Ahmad

    2017-10-01

    Mitochondrial damage and oxidative stress are known to contribute to the pathogenesis of noise-induced hearing loss (NIHL). In this study, we examined the protective effect of O 2 /O 3 mixture (ozone/oxygen) therapy against mitochondrial induced damage and oxidative stress by noise exposure in rat brain and cochlear. For this purpose, rats were divided into four groups: 1 - control group; 2 - noise-exposed group (100 dB); 3 - noise + O 2 /O 3 , and 4 - O 2 /O 3 (30 µg/ml). After 14 d, animals were anesthetised. Rat brain and cochlear tissue were removed for evaluation of the histopathological damages, oxidative stress, and mitochondrial dysfunction in both tissues. Our findings indicated that noise caused pathological damage, oxidative stress, and mitochondrial dysfunction in rat brain and cochlear. Also, daily administration of an O 2 /O 3 therapy (30 µg/ml intravenous) efficiently increased enzymatic and non-enzymatic antioxidant in brain and cochlear that this action led to inhibition of pathological damages, oxidative stress, reactive oxygen species formation, mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release resulting from noise. These findings suggest that the moderate O 2 /O 3 therapy enhances the capacity of enzymatic and non-enzymatic antioxidant in brain and cochlear that protects against NIHL.

  15. Fabrication and electrochemistry characteristics of nickel-doped diamond-like carbon film toward applications in non-enzymatic glucose detection

    Science.gov (United States)

    Liu, Chi-Wen; Chen, Wei-En; Sun, Yin Tung Albert; Lin, Chii-Ruey

    2018-04-01

    This research work focused on the fabrication of nickel-doped diamond-like carbon (DLC) films and their characteristics including of surface morphology, microstructure, and electrochemical aiming at applications in non-enzymatic glucose detection. Novel nanodiamond target was employed in unbalanced magnetron radio-frequency co-sputtering process to prepared high quality Ni-doped DLC thin film at room temperature. TEM analysis reveals a highly uniform distribution of Ni crystallites in amorphous carbon matrix with fraction ranged from 3 to 11.5 at.% which is considered as active sites for the glucose detection. Our cyclic voltammetry measurements using 0.1 M H2SO4 solution demonstrated that the as-prepared Ni-doped DLC films possess large electrochemical potential window of 2.12 V, and this was also observed to be significantly reduced at high Ni doping level owing to lower sp3 fraction. The non-enzymatic glucose detection investigation indicates that the Ni-doped DLC thin film electrode prepared under 7 W of DC sputtering power on Ni target possesses good detecting performance, high stability, and high sensitivity to glucose concentration up to 10 mM, even with the existence of uric acid and ascorbic acid. The peak current was observed to be proportional to glucose concentration and scanning rate, demonstrating highly reversibility redox process of the film electrode and glucose.

  16. Protective Effect of Slforafin on the Non-Enzymatic Antioxidants and Chromosomal Aberrations When Injected with Tc 99m Tin colloid in Mice

    International Nuclear Information System (INIS)

    Alwan, I.F.; Abd-Karim, H.M.; Ahmood, A.M.; Mohamad, H.A.

    2015-01-01

    Study aims to evaluated the preventive effect of (Slforafin ) compound extracted from Broccoli plant to effect on Technetium 99m irradiated isotope user to labeled Tin colloid and used in prevent several Tin colloid changes , antioxidant Non-Enzymatic ( vitamin A,E,C ) and some of the basic elements in serum , such as (Zn, Mn, Se, Mg and Cu) and (Chromosomal Aberrations ) in the bone marrow genes of laboratory animals .Slforafin compound was analyzed by High-performance liquid chromatography technique HPLC. Treated the laboratory animals daily with, concentration (200 mg / kg) of Slforafin Broccoli extract material through mouth for one week ,then were injected with (500 μci / 0.1 ml) doses of preparation Tc 99m Tin colloidal.The results indicated that there are significant differences (p< 0.05) at the deviation level of Non- enzymatic changes and chromosomal genes and some of the basic elements in serum of the Non –treated laboratory animals with Slforafin compound compared with the group of animals treated with (Slforafin) and injected with the same radiation dose compared with the control laboratory animal groups .

  17. Effect of topical application of fluoride gel NaF 2% on enzymatic and non-enzymatic antioxidant parameters of saliva.

    Science.gov (United States)

    Leite, Mariana Ferreira; Ferreira, Nayara Ferraz D'Assumpção; Shitsuka, Caleb David Willy Moreira; Lima, Amanda Martins; Masuyama, Mônica Miyuki; Sant'Anna, Giselle Rodrigues; Yamaguti, Paula Mochidome; Polotow, Tatiana G; de Barros, Marcelo Paes

    2012-06-01

    The aim of the study was to evaluate the effect of topical fluoride gel NaF 2% application on antioxidant parameters of whole saliva from children. The saliva mechanically stimulated with parafilm was collected from 25 children (6-12 years) attending the Clinic of Paediatric Dentistry of Universidade Cruzeiro do Sul, São Paulo, Brazil, before (control group) and immediately after application of neutral fluoride gel NaF 2% (fluoride-gel group), according to the Standards for Research Using Human Subjects, Resolution 196/96 of the USA National Health Council of 10/10/1996. Afterwards, pre-post ferric-reducing antioxidant power (FRAP), trolox-equivalent antioxidant capacity (TEAC), uric acid, reduced/oxidised glutathione content (GSH/GSSG) and total peroxidase activity (TPO) were evaluated in whole saliva of both groups. All non-enzymatic antioxidant parameters were augmented by fluoride-gel NaF 2% application, whereas a notable reduction (31%) of peroxidase activity was concomitantly observed in the children's saliva (p ≤ 0.05). Nevertheless, the reducing power of saliva was kept unaltered under these circumstances (p ≤ 0.05). Despite the reduced activity of peroxidase (an important antimicrobial and antioxidant enzyme), the topical fluoride gel NaF 2% favourably stimulated the release of non-enzymatic antioxidant components of saliva, sustaining the reducing power of saliva and the natural defences of the oral cavity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

    International Nuclear Information System (INIS)

    Xue, Zhonghua; He, Nan; Rao, Honghong; Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui; Lu, Xiaoquan

    2017-01-01

    Highlights: • A sensitive non-enzymatic glucose sensor was explored by using a facile and green strategy. • Well dispersed and uniform NiHCF nanoparticles can be effectively produced by the introduction of electrochemical reduction graphene oxide films. • Metal hexacyanoferrate as a potential electron mediator was proposed and applied into non-enzymatic sensing. - Abstract: Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

  19. Open tubular capillary electrochromatography: A useful microreactor for collagen I glycation and interaction studies with low-density lipoprotein particles

    Energy Technology Data Exchange (ETDEWEB)

    D' Ulivo, Lucia; Witos, Joanna [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland); Ooerni, Katariina; Kovanen, Petri T. [Wihuri Research Institute, Kalliolinnantie 4, FIN-00140, Helsinki (Finland); Riekkola, Marja-Liisa, E-mail: marja-liisa.riekkola@helsinki.fi [Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki (Finland)

    2010-04-07

    Diabetes, a multifunctional disease and a major cause of morbidity and mortality in the industrialized countries, strongly associates with the development and progression of atherosclerosis. One of the consequences of high level of glucose in the blood circulation is glycation of long-lived proteins, such as collagen I, the most abundant component of the extracellular matrix (ECM) in the arterial wall. Glycation is a long-lasting process that involves the reaction between a carbonyl group of the sugar and an amino group of the protein, usually a lysine residue. This reaction generates an Amadori product that may evolve in advanced glycation end products (AGEs). AGEs, as reactive molecules, can provoke cross-linking of collagen I fibrils. Since binding of low-density lipoproteins (LDLs) to the ECM of the inner layer of the arterial wall, the intima, has been implicated to be involved in the onset of the development of an atherosclerotic plaque, collagen modifications, which can affect the affinity of native and oxidized LDL for collagen I, can promote the entrapment of LDLs in the intima and accelerate the progression of atherosclerosis. In this study, open tubular capillary electrochromatography is proposed as a new microreactor to study in situ glycation of collagen I. The kinetics of glycation was first investigated in a fused silica collagen I-coated capillary. Dimethyl sulphoxide, injected as an electroosmotic flow marker, gave information about the charge of coating. Native and oxidized LDL, and selected peptide fragments from apolipoprotein B-100, the protein covering LDL particles, were injected as marker compounds to clarify the interactions between LDLs and the glycated collagen I coating. The method proposed is simple and inexpensive, since only small amounts of collagen and LDL are required. Atomic force microscopy images complemented our studies, highlighting the difference between unmodified and glycated collagen I surfaces.

  20. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Science.gov (United States)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  1. Plasma disappearance of glycated and non-glycated albumin in type 1 (insulin-dependent) diabetes mellitus

    DEFF Research Database (Denmark)

    Bent-Hansen, L; Feldt-Rasmussen, B; Kverneland, Arne

    1993-01-01

    The fractional plasma escape rates of glycated and non-glycated albumin have earlier been measured in groups of Type 1 (insulin-dependent) diabetic patients and control subjects. The escape of non-glycated albumin was similar in control subjects and normoalbuminuric patients, but elevated in pati...... to be the glycosaminoglycans of the glomerular basal membrane and the interstitial matrix....

  2. Relationship between glycated haemoglobin and fasting plasma ...

    African Journals Online (AJOL)

    Background: Glycated haemoglobin (HbA1c) measurement provides an accurate result of glycaemic levels from blood drawn at any time of day without reference to prandial state. We established the relationship between HbA1c and fasting plasma glucose (FPG) in diabetic out-patients among diabetic outpatients in Lusaka ...

  3. Below the Radar: Advanced Glycation End Products that Detour “around the side”: Is HbA1c not an accurate enough predictor of long term progression and glycaemic control in diabetes?

    OpenAIRE

    Forbes, Josephine M; Soldatos, Georgia; Thomas, Merlin C.

    2005-01-01

    Advanced glycation is the irreversible attachment of reducing sugars onto the free amino groups of proteins. Its physiological roles are thought to include the identification of senescent proteins and hence there is a time dependent accumulation of advanced glycation end products (AGEs). AGE labelled proteins are catabolised by cells into low molecular weight peptides and amino acids and excreted primarily via the kidneys. This process appears to be tightly controlled by AGE clearance recepto...

  4. Role of non enzymatic synthesis of indole-3-acetic acid in the Ipomoea batatas L. Lam. (sweet potato) response to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lage, C.L.S.; Esquibel, M.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Biofisica. Lab. de Fisiologia Vegetal

    1995-12-01

    Indolacetic acid (IAA) production by tryptophan radiolysis was evaluated after irradiation of a tryptophan solution (1.0 mg/ml) with a 2000 Gy dose of gamma rays followed by High Performance Liquid Chromatography (HPLC) analysis. New absorbance peaks at 280 nm were detected in the irradiated solution, one of them having a migration time similar to that of IAA, indicating a0.14% yield for the conversion reaction. The low yield led us to abandon the hypothesis that non-enzymatic IAA synthesis may account for growth simulation. When the electrophoretic patterns of peroxidases from absorbent roots derived from storage roots treated with IAA (1.0 mg/l) or gamma radiation were compared with control, differences were detected only in the irradiated material. Thus the growth radiation-induced effects do not seem to result from a sudden endogenous IAA increment. (author)

  5. Role of non enzymatic synthesis of indole-3-acetic acid in the Ipomoea batatas L. Lam. (sweet potato) response to gamma radiation

    International Nuclear Information System (INIS)

    Lage, C.L.S.; Esquibel, M.A.

    1995-01-01

    Indolacetic acid (IAA) production by tryptophan radiolysis was evaluated after irradiation of a tryptophan solution (1.0 mg/ml) with a 2000 Gy dose of gamma rays followed by High Performance Liquid Chromatography (HPLC) analysis. New absorbance peaks at 280 nm were detected in the irradiated solution, one of them having a migration time similar to that of IAA, indicating a0.14% yield for the conversion reaction. The low yield led us to abandon the hypothesis that non-enzymatic IAA synthesis may account for growth simulation. When the electrophoretic patterns of peroxidases from absorbent roots derived from storage roots treated with IAA (1.0 mg/l) or gamma radiation were compared with control, differences were detected only in the irradiated material. Thus the growth radiation-induced effects do not seem to result from a sudden endogenous IAA increment. (author)

  6. Non-enzymatic cyclic oxygenated metabolites of adrenic, docosahexaenoic, eicosapentaenoic and α-linolenic acids; bioactivities and potential use as biomarkers.

    Science.gov (United States)

    Galano, Jean-Marie; Lee, Jetty Chung-Yung; Gladine, Cecile; Comte, Blandine; Le Guennec, Jean-Yves; Oger, Camille; Durand, Thierry

    2015-04-01

    Cyclic oxygenated metabolites are formed in vivo through non-enzymatic free radical reaction of n-6 and n-3 polyunsaturated fatty acids (PUFAs) such as arachidonic (ARA C20:4 n-6), adrenic (AdA 22:4 n-6), α-linolenic (ALA 18:3 n-3), eicosapentaenoic (EPA 20:5 n-3) and docosahexaenoic (DHA 22:6 n-3) acids. These cyclic compounds are known as isoprostanes, neuroprostanes, dihomo-isoprostanes and phytoprostanes. Evidence has emerged for their use as biomarkers of oxidative stress and, more recently, the n-3PUFA-derived compounds have been shown to mediate bioactivities as secondary messengers. Accordingly, this review will focus on the cyclic oxygenated metabolites generated from AdA, ALA, EPA and DHA. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance". Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Oxidative degradation and non-enzymatic browning due to the interaction between oxidised lipids and primary amine groups in different marine PL emulsions

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Nielsen, Nina Skall; Baron, Caroline P.

    2012-01-01

    levels of triglycerides in the emulsions. The oxidative and hydrolytic stability of emulsions was investigated through measurement of peroxide value, free fatty acids, and 31P NMR during storage at 2 C for up to 32 days. The oxidative stability of marine PL emulsions during storage was further......Due to the beneficial health effects of marine phospholipids (PL) there is an increasing industrial interest in using them for nutritional applications including emulsified foods. This study was undertaken to investigate both oxidative and hydrolytic stability of marine PL emulsions in relation...... investigated through the measurement of secondary volatile compounds by solid-phase microextraction (SPME) and dynamic headspace (DHS) connected to gas chromatography (GC–MS). Non-enzymatic browning reactions were investigated through the measurement of Strecker derived volatiles, colour changes and pyrrole...

  8. Non-Enzymatic-Browning-Reaction: A Versatile Route for Production of Nitrogen-Doped Carbon Dots with Tunable Multicolor Luminescent Display

    Science.gov (United States)

    Wei, Weili; Xu, Can; Wu, Li; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

    2014-01-01

    The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicochemical properties of C-dots at will. Unexpectedly, the as-prepared C-dots possess bright photoluminescence with QY up to 69.1% which is almost the highest ever reported, favorable biocompatibility, excellent aqueous and nonaqueous dispersibility, ultrahigh photostability, and readily functionalization. We have demonstrated that they are particularly suitable for multicolor luminescent display and long-term and real-time cellular imaging. Furthermore, the methodology is readily scalable to large yield, and can provide sufficient amount of C-dots for practical demands.

  9. Effect of treatment with N-acetylcysteine on non-enzymatic antioxidant reserves and lipid peroxidation in workers exposed to lead

    Directory of Open Access Journals (Sweden)

    Sławomir Kasperczyk

    2014-06-01

    Full Text Available There are no published studies examining the effects of N-acetylcysteine (NAC administration on the non-enzymatic defence systems in humans exposed to lead. In view of this, it was decided to measure the levels of uric acid (UA, albumin, bilirubin and alpha-tocopherol before and after treatment with NAC. An estimation was also made of the degree of oxidative stress by measuring the ferric reducing ability of plasma (FRAP, the levels of conjugated dienes (CD and lipid hydroperoxides (LHP. Male employees who worked with lead were randomized into two groups. The first group included workers who were not administered any drugs (n=49, while the second group (n=122 consisted of workers who were treated with NAC at three different doses (200 mg, 400 mg and 800 mg for 12 weeks. The administration of NAC (400 mg, 800 mg resulted in significant decreases in the LHP levels. Similarly, a strong tendency toward lower levels of CD was observed in the same groups. The UA levels were significantly lower only in the group receiving the 200 mg dose of NAC. However, the alpha-tocopherol levels were significantly elevated after treatment with NAC (400 mg, 800 mg. NAC administration did not significantly affect the levels of bilirubin and albumin, but a tendency toward higher values was observed for FRAP. NAC reduced the extent of lipid peroxidation in a dose-dependent manner. Elevated concentrations of alpha-tocopherol may have enhanced the beneficial effects of NAC. Treatment with NAC may contribute to the restoration of non-enzymatic antioxidant reserves when administered to lead-exposed workers.

  10. A novel hierarchical 3D N-Co-CNT@NG nanocomposite electrode for non-enzymatic glucose and hydrogen peroxide sensing applications.

    Science.gov (United States)

    Balamurugan, Jayaraman; Thanh, Tran Duy; Karthikeyan, Gopalsamy; Kim, Nam Hoon; Lee, Joong Hee

    2017-03-15

    A novel 3D nanocomposite of nitrogen doped Co-CNTs over graphene sheets (3D N-Co-CNT@NG) have been successfully fabricated via a simple, scalable and one-step thermal decomposition method. This 3D hierarchical nanostructure provides an admirable conductive network for effective charge transfer and avoids the agglomeration of NG matrices, which examine direct as well as non-enzymatic responses to glucose oxidation and H 2 O 2 reduction at a low potential. The novel electrode showed excellent electrochemical performance towards glucose oxidation, with high sensitivity of 9.05μAcm -2 mM -1 , a wide linear range from 0.025 to 10.83mM, and a detection limit of 100nM with a fast response time of less than 3s. Furthermore, non-enzymatic H 2 O 2 sensors based on the 3D N-Co-CNT@NG electrode exhibited high sensitivity (28.66μAmM -1 cm -2 ), wide linear range (2.0-7449μM), low detection limit of 2.0μM (S/N=3), excellent selectivity, decent reproducibility and long term stability. Such outstanding electrochemical performance can be endorsed to the large electroactive surface area, unique porous architecture, highly conductive networks, and synergistic interaction between N-Co-CNTs and nitrogen doped graphene (NG) in the novel 3D nanocomposite. This facile, cost-effective, sensitive, and selective glucose as well as H 2 O 2 sensors are also proven to be appropriate for the detection of glucose as well as H 2 O 2 in human serum. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Non-enzymatic hydrogen peroxide detection at NiO nanoporous thin film- electrodes prepared by physical vapor deposition at oblique angles

    International Nuclear Information System (INIS)

    Salazar, Pedro; Rico, Victor; González-Elipe, Agustín R.

    2017-01-01

    Highlights: • A non-enzymatic sensor for H 2 O 2 detection based on nickel thin film is reported. • Nanostructured nickel thin films are prepared by physical vapor deposition at oblique angles. • Main analytical parameters were obtained under optimal operation conditions. • Sensors depict an outstanding selectivity and a high stability. • Sensors are successfully used to determine H 2 O 2 in antiseptic solutions. - Abstract: In this work we report a non-enzymatic sensor for hydrogen peroxide (H 2 O 2 ) detection based on nanostructured nickel thin films prepared by physical vapor deposition at oblique angles. Porous thin films deposited on ITO substrates were characterized by X-ray diffraction analysis, scanning electron microcopy (SEMs), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques such as Cyclic Voltammetry (CV) and Constant Potential Amperometry (CPA). The microstructure of the thin films consisted of inclined and separated Ni nanocolumns forming a porous thin layer of about 500 nm thickness. Prior to their use, the films surface was electrochemically modified and the chemical state studied by CV and XPS analysis. These techniques also showed that Ni 2+ /Ni 3+ species were involved in the electrochemical oxidation and detection of H 2 O 2 in alkaline medium. Main analytical parameters such as sensitivity (807 mA M −1 cm −2 ), limit of detection (3.22 μM) and linear range (0.011–2.4 mM) were obtained under optimal operation conditions. Sensors depicted an outstanding selectivity and a high stability and they were successfully used to determine H 2 O 2 concentration in commercial antiseptic solutions.

  12. Hierarchical 3-dimensional nickel-iron nanosheet arrays on carbon fiber paper as a novel electrode for non-enzymatic glucose sensing.

    Science.gov (United States)

    Kannan, Palanisamy; Maiyalagan, Thandavarayan; Marsili, Enrico; Ghosh, Srabanti; Niedziolka-Jönsson, Joanna; Jönsson-Niedziolka, Martin

    2016-01-14

    Three-dimensional nickel-iron (3-D/Ni-Fe) nanostructures are exciting candidates for various applications because they produce more reaction-active sites than 1-D and 2-D nanostructured materials and exhibit attractive optical, electrical and catalytic properties. In this work, freestanding 3-D/Ni-Fe interconnected hierarchical nanosheets, hierarchical nanospheres, and porous nanospheres are directly grown on a flexible carbon fiber paper (CFP) substrate by a single-step hydrothermal process. Among the nanostructures, 3-D/Ni-Fe interconnected hierarchical nanosheets show excellent electrochemical properties because of its high conductivity, large specific active surface area, and mesopores on its walls (vide infra). The 3-D/Ni-Fe hierarchical nanosheet array modified CFP substrate is further explored as a novel electrode for electrochemical non-enzymatic glucose sensor application. The 3-D/Ni-Fe hierarchical nanosheet arrays exhibit significant catalytic activity towards the electrochemical oxidation of glucose, as compared to the 3-D/Ni-Fe hierarchical nanospheres, and porous nanospheres. The 3-D/Ni-Fe hierarchical nanosheet arrays can access a large amount of glucose molecules on their surface (mesopore walls) for an efficient electrocatalytic oxidation process. Moreover, 3-D/Ni-Fe hierarchical nanosheet arrays showed higher sensitivity (7.90 μA μM(-1) cm(-2)) with wide linear glucose concentration ranging from 0.05 μM to 0.2 mM, and the low detection limit (LOD) of 0.031 μM (S/N = 3) is achieved by the amperometry method. Further, the 3-D/Ni-Fe hierarchical nanosheet array modified CFP electrode can be demonstrated to have excellent selectivity towards the detection of glucose in the presence of 500-fold excess of major important interferents. All these results indicate that 3-D/Ni-Fe hierarchical nanosheet arrays are promising candidates for non-enzymatic glucose sensing.

  13. 3D-copper oxide and copper oxide/few-layer graphene with screen printed nanosheet assembly for ultrasensitive non-enzymatic glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhimei [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Advanced Materials and Printed Electronics Center, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Pan, Peng, E-mail: panpeny@163.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Advanced Materials and Printed Electronics Center, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Liu, Xuewen [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Advanced Materials and Printed Electronics Center, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Yang, Zhengchun; Wei, Jun [Advanced Materials and Printed Electronics Center, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Wei, Zhen, E-mail: weizhenxinxi@163.com [Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China); Advanced Materials and Printed Electronics Center, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin, 300384 (China)

    2017-02-01

    Screen-printed copper oxide (CuO) and CuO/few-layer graphene on graphite electrodes were used to fabricate the ultrasensitive nonenzymatic glucose biosensors. Flower-like CuO and flower-like CuO/few-layer graphene composites were prepared by screen-printing method and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HETEM). On the basis of their cyclic voltammetry (CV) and chronoamperometry results, it was concluded that the addition of graphene to CuO significantly improved the performance of the fabricated glucose sensors, exhibiting high and reproducible sensitivity of 3120 μAmM{sup −1} cm{sup −2} with three linear ranges from 4 μM to 13.5 mM and the detection limit of 4 μM (S/N = 3) in a fast response time of 2 s. In addition, the fabricated sensors could effectively avoid the disturbance by interferents, such as Ascorbic Acid (AA), Uric Acid (UA), and Dopamine (DA). Most importantly, the testing results of real blood serum samples demonstrated that the electrodes were applicable and acceptable for the determination of glucose concentrations in human serum. The efficiencies of two non-enzymatic glucose biosensors for glucose determination were comparable with that of a commercial enzymatic sensor. - Highlights: • The method 2D nanosheet turns to 3D microflower by using screen printing was proposed. • Few-layer graphene added improved the sensor’s performance on base of CuO functional material. • Two ultrasensitive non-enzymatic glucose sensors were successfully fabricated. • The proposed sensor shows a high sensitivity of 3120 μA mM{sup −1} cm{sup −2}.

  14. Characterization and cytological effects of a novel glycated gelatine substrate

    International Nuclear Information System (INIS)

    Boonkaew, Benjawan; Supaphol, Pitt; Tompkins, Kevin; Manokawinchoke, Jeeranan; Pavasant, Prasit

    2014-01-01

    Hyperglycemia in diabetes results in the glycation of long-lived proteins. Protein glycation leads to the formation of advanced glycation end products (AGEs), which are implicated in delayed wound healing and other diabetes-associated pathologies, one of which is periodontal disease. Research into the mechanisms by which glycated long-lived proteins such as collagen exert their effects can allow for the understanding of diabetic pathologies and the development of appropriate treatments. However, the high cost of purified protein can be a limitation for many laboratories around the world. The objective of this study was to develop a low-cost in vitro model of glycated gelatine as an alternative to the glycated collagen model. We investigated the glycation of gelatine type A, a denatured form of collagen, which is low-cost and abundantly available. In this study, gelatine was incubated for 7 days with ribose or methylglyoxal (MG). Cross-linking, autofluorescence and UV–Vis spectrophotometry assays were performed and indicated a dose-dependent linear increase in cross-linking and autofluorescence of gelatine by ribose and MG. MG produced more cross-linking compared to ribose at the same concentrations. The UV–Vis spectra of the glycated gelatines confirmed the presence of AGE fluorophores. Because diabetes is a risk factor for periodontal disease, the effect of the glycated substrates on the basic behaviour of human periodontal ligament (HPDL) cells was evaluated. Glycation dose dependently reduced HPDL attachment and cell spreading, indicating that the novel glycated gelatine substrate affects cell behaviour. These results show that gelatine glycated with ribose or MG can be used as low-cost in vitro models to study the effects of protein glycation on cell behaviour in diabetes and ageing. (paper)

  15. The mechanism of reduced IgG/IgE-binding of β-lactoglobulin by pulsed electric field pretreatment combined with glycation revealed by ECD/FTICR-MS.

    Science.gov (United States)

    Yang, Wenhua; Tu, Zongcai; Wang, Hui; Zhang, Lu; Kaltashov, Igor A; Zhao, Yunlong; Niu, Chendi; Yao, Honglin; Ye, Wenfeng

    2018-01-24

    Bovine β-lactoglobulin (β-Lg) is a major allergen existing in milk and causes about 90% of IgE-mediated cow's milk allergies. Previous studies showed that pulsed electric field (PEF) treatment could partially unfold the protein, which may contribute to the improvement of protein glycation. In this study, the effect of PEF pretreatment combined with glycation on the IgG/IgE-binding ability and the structure of β-Lg was investigated. The result showed that PEF pretreatment combined with glycation significantly reduced the IgG and IgE binding abilities, which was attributed to the changes of secondary and tertiary structure and the increase in glycation sites and degree of substitution per peptide (DSP) value determined by electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry (ECD/FTICR-MS). Unexpectedly, glycation sites (K47, K91 and K135) added by two mannose molecules were identified in glycated β-Lg with PEF pretreatment. Moreover, the results indicated that PEF pretreatment at 25 kV cm -1 for 60 μs promoted the reduction of IgG/IgE-binding capacity by increasing the glycation degree of β-Lg, whereas single PEF treatment under the same conditions markedly enhanced the IgG/IgE-binding ability by partially unfolding the structure of β-Lg. The results suggested that ECD/FTICR-MS could help us to understand the mechanism of reduction in the IgG/IgE-binding of β-Lg by structural characterization at the molecular level. Therefore, PEF pretreatment combined with glycation may provide an alternative method for β-Lg desensitization.

  16. Intra-molecular lysine-arginine derived advanced glycation end-product cross-linking in Type I collagen: A molecular dynamics simulation study.

    Science.gov (United States)

    Collier, Thomas A; Nash, Anthony; Birch, Helen L; de Leeuw, Nora H

    2016-11-01

    Covalently cross-linked advanced glycation end products (AGE) are among the major post-translational modifications to proteins as a result of non-enzymatic glycation. The formation of AGEs has been shown to have adverse effects on the properties of the collagenous tissue; they are even linked to a number of age related disorders. Little is known about the sites at which these AGEs form or why certain sites within the collagen are energetically more favourable than others. In this study we have used a proven fully atomistic molecular dynamics approach to identify six sites where the formation of the intra-molecular 3-deoxyglucosone-derived imidazolium cross-link (DOGDIC) is energetically favourable. We have also conducted a comparison of these positions with those of the more abundant glucosepane cross-link, to determine any site preference. We show that when we consider both lysine and arginine AGEs, they exhibit a prevalence to form within the gap region of the collagen fibril. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Two acidic, anticoagulant PLA2 isoenzymes purified from the venom of monocled cobra Naja kaouthia exhibit different potency to inhibit thrombin and factor Xa via phospholipids independent, non-enzymatic mechanism.

    Directory of Open Access Journals (Sweden)

    Ashis K Mukherjee

    Full Text Available The monocled cobra (Naja kaouthia is responsible for snakebite fatality in Indian subcontinent and in south-western China. Phospholipase A2 (PLA2; EC 3.1.1.4 is one of the toxic components of snake venom. The present study explores the mechanism and rationale(s for the differences in anticoagulant potency of two acidic PLA2 isoenzymes, Nk-PLA2α (13463.91 Da and Nk-PLA2β (13282.38 Da purified from the venom of N. kaouthia.By LC-MS/MS analysis, these PLA2s showed highest similarity (23.5% sequence coverage with PLA2 III isolated from monocled cobra venom. The catalytic activity of Nk-PLA2β exceeds that of Nk-PLA2α. Heparin differentially regulated the catalytic and anticoagulant activities of these Nk-PLA2 isoenzymes. The anticoagulant potency of Nk-PLA2α was comparable to commercial anticoagulants warfarin, and heparin/antithrombin-III albeit Nk-PLA2β demonstrated highest anticoagulant activity. The anticoagulant action of these PLA2s was partially contributed by a small but specific hydrolysis of plasma phospholipids. The strong anticoagulant effect of Nk-PLA2α and Nk-PLA2β was achieved via preferential, non-enzymatic inhibition of FXa (Ki = 43 nM and thrombin (Ki = 8.3 nM, respectively. Kinetics study suggests that the Nk-PLA2 isoenzymes inhibit their "pharmacological target(s" by uncompetitive mechanism without the requirement of phospholipids/Ca(2+. The anticoagulant potency of Nk-PLA2β which is higher than that of Nk-PLA2α is corroborated by its superior catalytic activity, its higher capacity for binding to phosphatidylcholine, and its greater strength of thrombin inhibition. These PLA2 isoenzymes thus have evolved to affect haemostasis by different mechanisms. The Nk-PLA2β partially inhibited the thrombin-induced aggregation of mammalian platelets suggesting its therapeutic application in the prevention of unwanted clot formation.In order to develop peptide-based superior anticoagulant therapeutics, future application of Nk-PLA2

  18. Non-enzymatic browning due to storage is reduced by using clarified lemon juice as acidifier in industrial-scale production of canned peach halves.

    Science.gov (United States)

    Saura, Domingo; Vegara, Salud; Martí, Nuria; Valero, Manuel; Laencina, José

    2017-06-01

    Non-enzymatic browning (NEB) in canned peach halves in syrup during storage was investigated. Absorbance at 420 nm ( A 420 ), colorimetric parameters (CIE Lab , TCD and La / b ), fructose, glucose and sucrose, total sugar, organic acids, ascorbic acid (AA), dehydroascorbic acid, and 2,3-diketogulonic acid were used to estimate the extent of NEB during 1 year of storage at 30 °C and the relationships between each of these parameters and A 420 were established. The investigation was carried out to explore the possibility of replacing the E330 commonly used as acidifier by turbid or clarified lemon juice (TLJ or CLJ) to obtain a product having good nutrition with better retention of quality. The a , La / b , glucose and fructose were positively correlated with A 420 and all proved to be good indicators of browning development. Overall results showed that replacement of acidifier E330 with CLJ for controlling pH in canned peach halves in syrup had some advantages.

  19. Non-enzymatic browning reaction of glucosamine at mild conditions: Relationship between colour formation, radical scavenging activity and α-dicarbonyl compounds production.

    Science.gov (United States)

    Hong, Pui Khoon; Betti, Mirko

    2016-12-01

    Glucosamine (GlcN, 5% w/v) was incubated in either phosphate buffer or ammonium hydroxide solutions at 40 and 60°C for up to 48h in order to yield caramel solutions. Non-enzymatic browning was monitored via changes in absorption at 280, 320 and 420nm and the physico-chemical properties as well as the generation of short chain α-dicarbonyl compounds were evaluated. Accumulation of GlcN autocondensation products (280nm) proceeded in parallel with the development of pre-melanoidins (320nm) and melanoidins (420nm). The reactive α-dicarbonyls were detected at temperature as low as 40°C within 3h with a maximum level of diacetyl recorded at 6h. The caramel solutions showed a high efficacy in scavenging DPPH and ABTS radicals in accordance with the increasing browning intensity. The results suggest that GlcN browning can be modulated according to the specific desired properties to produce a multi-functional food ingredient that has health-promoting effects. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Co3O4 based non-enzymatic glucose sensor with high sensitivity and reliable stability derived from hollow hierarchical architecture

    Science.gov (United States)

    Tian, Liangliang; He, Gege; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Yang, Cong; Chen, Yanling; Li, Lu

    2018-02-01

    Inspired by kinetics, the design of hollow hierarchical electrocatalysts through large-scale integration of building blocks is recognized as an effective approach to the achievement of superior electrocatalytic performance. In this work, a hollow, hierarchical Co3O4 architecture (Co3O4 HHA) was constructed using a coordinated etching and precipitation (CEP) method followed by calcination. The resulting Co3O4 HHA electrode exhibited excellent electrocatalytic activity in terms of high sensitivity (839.3 μA mM-1 cm-2) and reliable stability in glucose detection. The high sensitivity could be attributed to the large specific surface area (SSA), ample unimpeded penetration diffusion paths and high electron transfer rate originating from the unique two-dimensional (2D) sheet-like character and hollow porous architecture. The hollow hierarchical structure also affords sufficient interspace for accommodation of volume change and structural strain, resulting in enhanced stability. The results indicate that Co3O4 HHA could have potential for application in the design of non-enzymatic glucose sensors, and that the construction of hollow hierarchical architecture provides an efficient way to design highly active, stable electrocatalysts.

  1. Ternary nanohybrid of reduced graphene oxide-nafion@silver nanoparticles for boosting the sensor performance in non-enzymatic amperometric detection of hydrogen peroxide.

    Science.gov (United States)

    Yusoff, Norazriena; Rameshkumar, Perumal; Mehmood, Muhammad Shahid; Pandikumar, Alagarsamy; Lee, Hing Wah; Huang, Nay Ming

    2017-01-15

    A sensitive and novel electrochemical sensor was developed for the detection of hydrogen peroxide (H 2 O 2 ) using a reduced graphene oxide-nafion@silver6 (rGO-Nf@Ag6) nanohybrid modified glassy carbon electrode (GC/rGO-Nf@Ag6). The GC/rGO-Nf@Ag6 electrode exhibited an excellent electrochemical sensing ability for determining H 2 O 2 with high sensitivity and selectivity. The detection limit of the electrochemical sensor using the GC/rGO-Nf@Ag6 electrode for H 2 O 2 determination was calculated to be 5.35×10 -7 M with sensitivity of 0.4508µAµM -1 . The coupling between rGO-Nf with silver nanoparticles (AgNPs) significantly boosted the electroanalytical performance by providing more active area for analyte interaction, thereby allowing more rapid interfacial electron transfer process. The interfering effect on the current response of H 2 O 2 was studied and the results revealed that the sensor electrode exhibited an excellent immunity from most common interferents. The proposed non-enzymatic electrochemical sensor was used for determining H 2 O 2 in apple juice, and the sensor electrode provided satisfactory results with reliable recovery values. These studies revealed that the novel GC/rGO-Nf@Ag6 sensor electrode could be a potential candidate for the detection of H 2 O 2 . Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Facile fabrication of chitosan-calcium carbonate nanowall arrays and their use as a sensitive non-enzymatic organophosphate pesticide sensor

    Science.gov (United States)

    Gong, Jingming; Zhang, Wei; Liu, Ting; Zhang, Lizhi

    2011-08-01

    Novel nanowall arrays of CaCO3-chitosan (CaCO3-chi) were deposited onto a cathodic substrate by a facile one-step electrodeposition approach. Results demonstrate that chitosan plays an important role in the formation of nanowall arrays. Freestanding well-aligned CaCO3-chi nanowall arrays were observed to be uniformly distributed over the whole substrate with a lateral dimension in the micrometre size and an average pore size of ~400 nm. The as-formed CaCO3-chi nanowall arrays featuring interlaced porous network architecture, large surface area, and open boundaries, are highly efficient in the capture of organophosphate pesticides (OPs). Combined with stripping voltammetry, a highly sensitive non-enzymatic OPs sensor was fabricated using the prepared CaCO3-chi nanowall arrays for solid phase extraction (SPE). The detection limit for methyl parathion (MP) in aqueous solutions was determined to be 0.8 ng mL-1 (S/N = 3). The resulting sensor made of novel CaCO3-chi nanowall arrays exhibits good reproducibility and acceptable stability. This work not only provides a facile and effective route for the preparation of CaCO3-chi nanowall arrays, but also offers a new promising protocol for OPs analysis.

  3. Effect of formulation and baking conditions on the structure and development of non-enzymatic browning in biscuit models using images.

    Science.gov (United States)

    Leiva-Valenzuela, Gabriel A; Quilaqueo, Marcela; Lagos, Daniela; Estay, Danilo; Pedreschi, Franco

    2018-04-01

    The aim of this research was to determine the effect of composition (dietary fiber = DF, fat = F, and gluten = G) and baking time on the target microstructural parameters that were observed using images of potato and wheat starch biscuits. Microstructures were studied Scanning Electron Microscope (SEM). Non-enzymatic browning (NEB) was assessed using color image analysis. Texture and moisture analysis was performed to have a better understanding of the baking process. Analysis of images revealed that the starch granules retained their native form at the end of baking, suggesting their in complete gelatinization. Granules size was similar at several different baking times, with an average equivalent diameter of 9 and 27 µm for wheat and potato starch, respectively. However, samples with different levels of DF and G increased circularity during baking to more than 30%, and also increasing hardness. NEB developed during baking, with the maximum increase observed between 13 and 19 min. This was reflected in decreased luminosity (L*) values due to a decrease in moisture levels. After 19 min, luminosity did not vary significantly. The ingredients that are used, as well as their quantities, can affect sample L* values. Therefore, choosing the correct ingredients and quantities can lead to different microstructures in the biscuits, with varying amounts of NEB products.

  4. Non-Enzymatic Electrochemical Sensing of Malathion Pesticide in Tomato and Apple Samples Based on Gold Nanoparticles-Chitosan-Ionic Liquid Hybrid Nanocomposite

    Directory of Open Access Journals (Sweden)

    Gulcin Bolat

    2018-03-01

    Full Text Available Malathion (MLT is an organophosphorous type pesticide and having seriously high toxicity and electrochemical platforms for rapid, simple, inexpensive and sensitive determination of pesticides is still a special concern. This paper describes a simple preparation of a composite film consisting of ionic liquid (IL, chitosan (CS and electrochemically synthesized gold nanoparticles (AuNPs on single use pencil graphite electrodes (PGEs. The microscopic and electrochemical characterization of AuNP-CS-IL/PGE was studied using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. This fabricated surface was then explored for the first time as a sensing matrix for the non-enzymatic electrochemical sensing of malathion by cyclic voltammetry and square wave voltammetry measurements. The proposed AuNP-CS-IL/PGE showed excellent characteristics and possessed remarkable affinity for malathion. The voltammetric current response exhibited two linear dynamic ranges, 0.89–5.94 nM and 5.94–44.6 nM reflecting two binding sites, with a detection limit of 0.68 nM. The method was applied in real sample analysis of apple and tomato. The results demonstrate the feasibility of AuNP-CS-IL-modified electrodes for simple, fast, ultrasensitive and inexpensive detection of MLT.

  5. Effects of thyroid status on glycated hemoglobin

    OpenAIRE

    Bhattacharjee, Rana; Thukral, Anubhav; Chakraborty, Partha Pratim; Roy, Ajitesh; Goswami, Soumik; Ghosh, Sujoy; Mukhopadhyay, Pradip; Mukhopadhyay, Satinath; Chowdhury, Subhankar

    2017-01-01

    Introduction: Glycated hemoglobin (HbA1c) can be altered in different conditions. We hypothesize that HbA1c levels may change due to altered thyroid status, possibly due to changes in red blood cell (RBC) turnover. Objectives: The objective of this study was to determine the effects of altered thyroid status on HbA1c levels in individuals without diabetes, with overt hyper- and hypo-thyroidism, and if present, whether such changes in HbA1c are reversed after achieving euthyroid state. Methods...

  6. Evaluation of a reference material for glycated haemoglobin

    NARCIS (Netherlands)

    Weykamp, CW; Penders, TJ; Muskiet, FAJ; vanderSlik, W

    The use of lyophilized blood as a reference material for glycated haemoglobin was investigated with respect to IFCC criteria for calibrators and control materials. Ninety-two laboratories, using 11 methods, detected no changes in glycated haemoglobin content when the lyophilizate was stored for one

  7. GLYCATED HEMOGLOBIN AND FRUCTOSAMINE IN DOGS WITH DIABETES MELLITUS

    Directory of Open Access Journals (Sweden)

    Olair Carlos Beltrame

    2015-10-01

    Full Text Available Diabetes mellitus (DM commonly occurs in dogs, and the laboratorial confirmation is carried out by glycemia test. The diagnosis and monitoring in humans is made by glycated hemoglobin and fructosamine concentrations. The objective of this study was to diagnose DM in 19 dogs, by evaluating seric glucose, glycated hemoglobin and fructosamine concentrations. Six dogs with DM and treated with insulin were assisted during a twelve-month period, by means of the same blood analysis, until the death (three dogs or glycemic control (three dogs. Glucose, glycated hemoglobin and fructosamine increased in all dogs with DM, and dogs that did not survive presented higher glycated hemoglobin and seric glucose values than those that survived at the last evaluation. The results showed the importance of evaluating glycated hemoglobin and fructosamine in dogs with DM to diagnose and control treatment effectiveness.

  8. Advanced glycation end product ligands for the receptor for advanced glycation end products: Biochemical characterization and formation kinetics

    NARCIS (Netherlands)

    Valencia, J.V.; Weldon, S.C.; Quinn, D.; Kiers, G.H.; Groot, J. de; TeKoppele, J.M.; Hughes, T.E.

    2004-01-01

    Advanced glycation end products (AGEs) accumulate with age and at an accelerated rate in diabetes. AGEs bind cell-surface receptors including the receptor for advanced glycation end products (RAGE). The dependence of RAGE binding on specific biochemical characteristics of AGEs is currently unknown.

  9. Diabetic threesome (hyperglycaemia, renal function and nutrition) and advanced glycation end products: evidence for the multiple-hit agent?

    Science.gov (United States)

    Kanková, Katerina

    2008-02-01

    Complex chemical processes termed non-enzymic glycation that operate in vivo and similar chemical interactions between sugars and proteins that occur during thermal processing of food (known as the Maillard reaction) are one of the interesting examples of a potentially-harmful interaction between nutrition and disease. Non-enzymic glycation comprises a series of reactions between sugars, alpha-oxoaldehydes and other sugar derivatives and amino groups of amino acids, peptides and proteins leading to the formation of heterogeneous moieties collectively termed advanced glycation end products (AGE). AGE possess a wide range of chemical and biological properties and play a role in diabetes-related pathology as well as in several other diseases. Diabetes is, nevertheless, of particular interest for several reasons: (1) chronic hyperglycaemia provides the substrates for extracellular glycation as well as intracellular glycation; (2) hyperglycaemia-induced oxidative stress accelerates AGE formation in the process of glycoxidation; (3) AGE-modified proteins are subject to rapid intracellular proteolytic degradation releasing free AGE adducts into the circulation where they can bind to several pro-inflammatory receptors, especially receptor of AGE; (4) kidneys, which are principally involved in the excretion of free AGE adducts, might be damaged by diabetic nephropathy, which further enhances AGE toxicity because of diminished AGE clearance. Increased dietary intake of AGE in highly-processed foods may represent an additional exogenous metabolic burden in addition to AGE already present endogenously in subjects with diabetes. Finally, inter-individual genetic and functional variability in genes encoding enzymes and receptors involved in either the formation or the degradation of AGE could have important pathogenic, nutrigenomic and nutrigenetic consequences.

  10. Unraveling the mechanism responsible for the contrasting tolerance of Synechocystis and Synechococcus to Cr(VI): Enzymatic and non-enzymatic antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Alka [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Ballal, Anand, E-mail: aballal@barc.gov.in [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 40085 (India)

    2015-07-15

    Highlights: • Cr(VI) accumulation generates higher ROS in Synechocystis than in Synechococcus. • Synechococcus exhibits better photosynthetic activity in response to Cr(VI). • Synechococcus has higher enzymatic/non-enzymatic antioxidants than Synechocystis. • Synechococcus shows better tolerance to other oxidative stresses than Synechocystis. • Differential detoxification of ROS is responsible for the contrasting tolerance to Cr(VI) - Abstract: Two unicellular cyanobacteria, Synechocystis and Synechococcus, showed contrasting tolerance to Cr(VI); with Synechococcus being 12-fold more tolerant than Synechocystis to potassium dichromate. The mechanism responsible for this differential sensitivity to Cr(VI) was explored in this study. Total content of photosynthetic pigments as well as photosynthetic activity decreased at lower concentration of Cr(VI) in Synechocystis as compared to Synechococcus. Experiments with {sup 51}Cr showed Cr to accumulate intracellularly in both the cyanobacteria. At lower concentrations, Cr(VI) caused excessive ROS generation in Synechocystis as compared to that observed in Synechococcus. Intrinsic levels of enzymatic antioxidants, i.e., superoxide dismutase, catalase and 2-Cys-peroxiredoxin were considerably higher in Synechococcus than Synechocystis. Content of total thiols (both protein as well as non-protein) and reduced glutathione (GSH) was also higher in Synechococcus as compared to Synechocystis. This correlated well with higher content of carbonylated proteins observed in Synechocystis than Synechococcus. Additionally, in contrast to Synechocystis, Synechococcus exhibited better tolerance to other oxidative stresses like high intensity light and H{sub 2}O{sub 2}. The data indicate that the disparity in the ability to detoxify ROS could be the primary mechanism responsible for the differential tolerance of these cyanobacteria to Cr(VI)

  11. Non-enzymatic detection of hydrogen peroxide based on Fenton-type reaction on poly(azure A)-chitosan/Cu modified electrode

    International Nuclear Information System (INIS)

    Liu, Tong; Luo, Yiqun; Wang, Wen; Kong, Liyan; Zhu, Jiaming; Tan, Liang

    2015-01-01

    Highlights: • The PAA-CS modified GCE was prepared using cyclic voltammetry. • Copper ions were strongly bound to the PAA-CS composites by complexation. • ·OH derived from the reaction between Cu 2+ and H 2 O 2 effectively oxidized PAA. • An electrochemical sensor of H 2 O 2 with good analytical performance was developed. - Abstract: In this work, a sensitive electrochemical method for the detection of H 2 O 2 was proposed based on Fenton-type reaction on the electrode surface. A glassy carbon electrode modified with poly(azure A) (PAA), chitosan (CS) and copper ions, displaying a good electrochemical activity, was fabricated by cyclic voltammetry and the adsorption of Cu 2+ . Scanning electron microscopy-Energy dispersive spectroscopy analysis, infrared and Raman spectral characterization and XPS measurement showed the stable complexation of Cu 2+ with the PAA-CS film. Hydroxyl radicals derived from the Fenton-type reaction between Cu 2+ and H 2 O 2 could effectively oxidize poly(azure A), leading to the great reduction-current change of the dye polymer in the electrode process. Under the optimized conditions, the fabricated electrode displayed a linear response in the H 2 O 2 concentration range from 0.002 to 0.5 mM and that from 2.56 to 25.0 mM with a detection limit of 0.7 μM estimated at a signal-to-noise ratio of 3. The good analytical performance including low detection limit, fast response time, low cost, good anti-interference performance, satisfying stability, acceptable repeatability and reliable reproducibility were found from the proposed amperometric sensor, suggesting that the current work could provide a feasible approach for the non-enzymatic H 2 O 2 detection.

  12. A novel non-enzymatic glucose sensor based on the modification of carbon paste electrode with CuO nanoflower: Designing the experiments by response surface methodology (RSM).

    Science.gov (United States)

    Amani-Beni, Zahra; Nezamzadeh-Ejhieh, Alireza

    2017-10-15

    A non enzymatic modified electrode was constructed based on the modification of carbon paste electrode with CuO nanoflower (CuO-CPE). The raw and modified samples were characterized by XRD, TEM, SEM-EDX and X-ray mapping techniques. The proposed CuO-CPE showed a well voltammetric peak pair in cyclic voltammetry which of peak currents were decreased in the presence of glucose. Hence, this decrease in peak current was used for voltammetric determination of glucose. To evaluate interactions between the influencing variables, experiments were designed by response surface methodology (RSM) and the results showed CuO%-pH have the most effect on square wave voltammetric response. The best response was obtained in a run including 20% CuO modifier, pH 3.6, amplitude 0.106V, step potential 0.0074V and frequency 17.75Hz. Calibration curve was constructed and a linear response between ΔIp (difference of peak current in the presence and absence of glucose in SqW voltammograms) and glucose concentration was obtained in concentration range from 0.06 to 10mmolL -1 [calibration equation: ΔI (μA)=91.35 C glucose +523.12, R 2 =0.9967] with detection and quantification limits of 7.49×10 -10 and 2.49×10 -9 molL -1 , respectively. The modified electrode can be used satisfactory in determination of glucose in real samples such as human blood serum. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Age-adjusted glycated albumin accurately reflects blood glucose in patients with neonatal diabetes mellitus: comparison with calculated glycated albumin determined by past blood glucose concentrations.

    Science.gov (United States)

    Suzuki, Shigeru; Furuya, Akiko; Oshima, Miho; Amamiya, Satoshi; Nakao, Atsushi; Wada, Keiko; Okuhara, Koji; Hayano, Satoshi; Imamoto, Aya; Matsuo, Kumihiro; Tanahashi, Yusuke; Azuma, Hiroshi; Koga, Masafumi

    2016-01-01

    Glycated albumin is a useful glycaemic control indicator for neonatal diabetes mellitus. However, glycated albumin concentrations in infants are lower than those in adults and increase in an age-dependent manner. Based on our investigation of non-diabetic subjects, we proposed the possibility that the reference range for adults may be used regardless of age, provided that age-adjusted glycated albumin is employed. In the present study, we evaluate the usefulness of age-adjusted glycated albumin in neonatal diabetes mellitus patients. Six neonatal diabetes mellitus patients (four patients with permanent neonatal diabetes mellitus and two patients with transient neonatal diabetes mellitus) were included. Measured glycated albumin or age-adjusted glycated albumin was compared to calculated glycated albumin, which was determined using calculation formulae we had reported based on past blood glucose over the 50 days before measurement of glycated albumin. Measured glycated albumin was significantly lower than calculated glycated albumin (20.5 ± 4.9% versus 28.2 ± 6.1%; p diabetes mellitus in remission were lower than the reference range for adults, whereas age-adjusted glycated albumin concentrations were within the reference range for adults. We demonstrated that age-adjusted glycated albumin concentrations were consistent with calculated glycated albumin. Age-adjusted glycated albumin is therefore a useful glycaemic control indicator for neonatal diabetes mellitus patients. © The Author(s) 2015.

  14. Human Achilles tendon glycation and function in diabetes

    DEFF Research Database (Denmark)

    Couppe, Christian; Svensson, Rene Brüggebusch; Kongsgaard, Mads

    2016-01-01

    Diabetic patients have an increased risk of foot ulcers, and glycation of collagen may increase tissue stiffness. We hypothesized that the level of glycemic control (glycation) may affect Achilles tendon stiffness, which can influence gait pattern. We therefore investigated the relationship between...... collagen glycation, Achilles tendon stiffness parameters and plantar pressure in poorly (n = 22) and well (n = 22) controlled diabetic patients, including healthy age matched (45-70 yrs) controls (n = 11). There were no differences in any of outcome parameters (collagen cross-linking or tendon stiffness...... concentrations (55%, P tendon material stiffness was higher in DB (54%, P tendon material stiffness and skin connective...

  15. Gibberellin-like effects of KAR1 on dormancy release of Avena fatua caryopses include participation of non-enzymatic antioxidants and cell cycle activation in embryos.

    Science.gov (United States)

    Cembrowska-Lech, Danuta; Kępczyński, Jan

    2016-02-01

    The induction of dormancy release and germination of Avena fatua caryopses by KAR 1 involves ABA degradation to phaseic acid. Both, KAR 1 and GA 3 , control the AsA-GSH cycle, DNA replication and accumulation of β-tubulin in embryos before caryopses germination. Avena fatua caryopses cannot germinate in darkness at 20 °C because of dormancy, but karrikinolide-1 (KAR1), a compound in plant-derived smoke, and gibberellic acid (GA3) induced an almost complete germination. The radicle protrusion through the coleorhiza was preceded by increased water uptake, rupture of coat, increased embryo size and coleorhiza length as well as coleorhiza protrusion through covering structures. The stimulatory effect of KAR1 was correlated with the reduced content of abscisic acid (ABA) and an increase in phaseic acid (PA) in embryos from caryopses before coleorhiza protrusion. Two non-enzymatic antioxidants, ascorbate (AsA) and reduced glutathione (GSH), did not affect the germination of dormant caryopses, but in the presence of KAR1 or GA3 they only slightly delayed the germination. The stimulatory effect of KAR1 or GA3 on the final germination percentage was markedly antagonized by lycorine, an AsA biosynthesis inhibitor. KAR1 and GA3 applied during caryopses imbibition resulted in increases of AsA, dehydroascorbate (DHA) and GSH, but reduced the embryos' oxidized glutathione (GSSG) content. Furthermore, both KAR1 and GA3 induced an additional ascorbate peroxidase (APX) isoenzyme and increased the glutathione reductase (GR) activity. Both compounds stimulated β-tubulin accumulation in radicle+coleorhiza (RC) and plumule+coleoptile (PC), and enhanced the transition from G1 to S and also from S to G2 phases. The comparison of the effects produced by KAR1 and GA3  shows a similar action; thus the KAR1 effect may not be specific. The study provides new data regarding the mechanism with which KAR1, a representative of a novel class of plant growth regulators, regulates dormancy and

  16. MnO{sub x}/C nanocomposite: An insight on high-performance supercapacitor and non-enzymatic hydrogen peroxide detection

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, Preety, E-mail: drpreetyahuja@gmail.com [Department of Chemistry, Jamia Hamdard, Delhi 110062 (India); Kumar Ujjain, Sanjeev [Department of Physics, Indian Institute of Technology, Kanpur, UP 208016 (India); Kanojia, Rajni [Department of Chemistry, Shivaji College, University of Delhi, Delhi 110027 (India)

    2017-05-15

    Graphical abstract: In-situ inclusion of carbon matrix during growth of MnO{sub x} nanoparticles resulted in MnO{sub x}/C nanocomposite with enhanced electronic diffusion leading to high energy/power densities supercapacitor and highly sensitive H{sub 2}O{sub 2} sensor. - Highlights: • MnO{sub x}/C, synthesized via microemulsion method, is electrochemically investigated towards supercapacitor and sensing applications. • In-situ inclusion of conducting carbon in manganese oxide enhances the network conductivity facilitating the charge transfer process. • It provides high energy and power density, 31.6 Wh kg{sup −1} and 3.8 kW kg{sup −1} respectively, with short relaxation time ∼3 ms for fabricated cell. • MnO{sub x}/C as sensor, exhibits excellent catalytic activity toward H{sub 2}O{sub 2} oxidation and offer high sensitivity with low detection limit. - Abstract: In this work, we have used microemulsion method for synthesis of MnO{sub x}/C nanocomposite and investigated its electrochemical properties via fabrication of supercapacitor and non-enzymatic hydrogen peroxide (H{sub 2}O{sub 2}) sensor. In-situ inclusion of conducting carbon in manganese oxide (MnO{sub x}/C) enhances the network conductivity facilitating the charge transfer process which is beneficial for supercapacitor and sensing applications. MnO{sub x}/C provides high energy and power density, 31.6 Wh kg{sup −1} and 3.8 kW kg{sup −1} respectively and short relaxation time ∼3 ms for fabricated cell (MnO{sub x}/C//MnO{sub x}/C) endowing excellent power delivery capacity. Furthermore, MnO{sub x}/C as sensor, exhibits excellent catalytic activity toward the oxidation of H{sub 2}O{sub 2} and shows high sensitivity (0.37 mA mM{sup −1} cm{sup −2}) with low detection limit (0.5 μM at an S/N of 3). Hence, this study provides new avenue for high performance supercapacitor and H{sub 2}O{sub 2} detection.

  17. Open-tubular capillary electrochromatography with bare gold nanoparticles-based stationary phase applied to separation of trypsin digested native and glycated proteins

    Czech Academy of Sciences Publication Activity Database

    Mikšík, Ivan; Lacinová, Kateřina; Zmatlíková, Zdeňka; Sedláková, Pavla; Král, V.; Sýkora, D.; Řezanka, P.; Kašička, Václav

    2012-01-01

    Roč. 35, č. 8 (2012), s. 994-1002 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA203/09/0675; GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z40550506 Keywords : capillary electrochromatography * gold nanoparticles * glycation * peptide maps * proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.591, year: 2012

  18. Potent protein glycation inhibition of plantagoside in Plantago major seeds.

    Science.gov (United States)

    Matsuura, Nobuyasu; Aradate, Tadashi; Kurosaka, Chihiro; Ubukata, Makoto; Kittaka, Shiho; Nakaminami, Yuri; Gamo, Kanae; Kojima, Hiroyuki; Ohara, Mitsuharu

    2014-01-01

    Plantagoside (5,7,4',5'-tetrahydroxyflavanone-3'-O-glucoside) and its aglycone (5,7,3',4',5'-pentahydroxyflavanone), isolated from a 50% ethanol extract of Plantago major seeds (Plantaginaceae), were established to be potent inhibitors of the Maillard reaction. These compounds also inhibited the formation of advanced glycation end products in proteins in physiological conditions and inhibited protein cross-linking glycation. These results indicate that P. major seeds have potential therapeutic applications in the prevention of diabetic complications.

  19. GLYCATED HEMOGLOBIN AND FRUCTOSAMINE IN DOGS WITH DIABETES MELLITUS

    OpenAIRE

    Olair Carlos Beltrame; Rosangela Locatelli-Dittrich; Luciane Maria Laskoski; Lia Fordiani Lenati Patricio; Nina da Cunha Medeiros; Marília Oliveira Koch

    2015-01-01

    Diabetes mellitus (DM) commonly occurs in dogs, and the laboratorial confirmation is carried out by glycemia test. The diagnosis and monitoring in humans is made by glycated hemoglobin and fructosamine concentrations. The objective of this study was to diagnose DM in 19 dogs, by evaluating seric glucose, glycated hemoglobin and fructosamine concentrations. Six dogs with DM and treated with insulin were assisted during a twelve-month period, by means of the same blood analysis, until the death...

  20. Commercial processed soy-based food product contains glycated and glycoxidated lunasin proteoforms.

    Science.gov (United States)

    Serra, Aida; Gallart-Palau, Xavier; See-Toh, Rachel Su-En; Hemu, Xinya; Tam, James P; Sze, Siu Kwan

    2016-05-18

    Nutraceuticals have been proposed to exert positive effects on human health and confer protection against many chronic diseases. A major bioactive component of soy-based foods is lunasin peptide, which has potential to exert a major impact on the health of human consumers worldwide, but the biochemical features of dietary lunasin still remain poorly characterized. In this study, lunasin was purified from a soy-based food product via strong anion exchange solid phase extraction and then subjected to top-down mass spectrometry analysis that revealed in detail the molecular diversity of lunasin in processed soybean foods. We detected multiple glycated proteoforms together with potentially toxic advanced glycation end products (AGEs) derived from lunasin. In both cases, modification sites were Lys24 and Lys29 located at the helical region that shows structural homology with a conserved region of chromatin-binding proteins. The identified post-translational modifications may have an important repercussion on lunasin epigenetic regulatory capacity. Taking together, our results demonstrate the importance of proper chemical characterization of commercial processed food products to assess their impact on consumer's health and risk of chronic diseases.

  1. Serum glycated albumin as a new glycemic marker in pediatric diabetes

    Directory of Open Access Journals (Sweden)

    Ji Woo Lee

    2013-12-01

    Full Text Available PurposeSerum glycated albumin (GA has been recently used as another glycemic marker that reflects shorter term glycemic control than glycated hemoglobin (HbA1c. Insulin secretory function and glycemic fluctuation might be correlated with the ratio of GA to HbA1c (GA/HbA1c in diabetic adult patients. This study investigated the association of GA and GA/HbA1c ratio with the levels of fasting C-peptide, fasting plasma glucose in type 1 and type 2 pediatric diabetes.MethodsTotal 50 cases from 42 patients were included. The subjects were classified into type 1 diabetes mellitus (T1DM (n=30 and type 2 diabetes mellitus (T2DM (n=20 group. The associations among HbA1c, GA, and GA/HbA1c ratio were examined. The relationship between the three glycemic indices and fasting glucose, fasting C-peptide were analyzed.ResultsMean values of GA, the GA/HbA1c ratio were significantly higher in T1DM than T2DM. GA (r=0.532, P=0.001, HbA1c (r=0.519, P=0.002 and the GA/HbA1c ratio (r=0.409, P=0.016 were correlated with the fasting plasma glucose. Fasting C-peptide level arranged 4.22±3.22 ng/mL in T2DM, which was significantly above the values in T1DM (0.26±0.49 ng/mL. There were no significant correlation between HbA1c and fasting C-peptide level. However, GA and the GA/HbA1c ratio exhibited inverse correlations with fasting C-peptide level (r=-0.214, P=0.002; r=-0.516, P<0.001.ConclusionGA seems to more accurately reflects fasting plasma glucose level than HbA1c. GA, GA/HbA1c ratio appear to reflect insulin secretory function.

  2. Glycated human serum albumin induces NF-κB activation and endothelial nitric oxide synthase uncoupling in human umbilical vein endothelial cells.

    Science.gov (United States)

    Rodiño-Janeiro, Bruno K; Paradela-Dobarro, Beatriz; Raposeiras-Roubín, Sergio; González-Peteiro, Mercedes; González-Juanatey, José R; Álvarez, Ezequiel

    2015-01-01

    Non-enzymatic glycated proteins could mediate diabetes vascular complications, but the molecular mechanisms are unknown. Our objective was to find new targets involved in the glycated human serum albumin (gHSA)-enhanced extracellular reactive oxygen species (ROS) production in human endothelial cells. Some nuclear factors and phosphorylation cascades were analysed. gHSA activated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which up-regulated NOX4 and P22PHOX and enhanced ROS production. Pharmacological inhibition of NF-κB reversed gHSA-enhanced NOX4 expression and decreased gHSA-induced ROS production in extra- and intracellular spaces. The inhibition of activator protein-1 (AP-1) induced a rise in NOX4 and P22PHOX subunit expression and a down-regulation of endothelial nitric oxide synthase (eNOS). AP-1 inhibition also enhanced extracellular ROS production in the presence of serum albumin, but not with gHSA. These results were explained by the eNOS uncoupling induced by gHSA, also demonstrated in this study. Phosphatidylinositol 3-kinase or mitogen-activated protein kinase kinase 1/2 did not show to be involved in gHSA-induced ROS production. All together, the results suggested that gHSA-enhanced ROS production in endothelium is mediated by: 1) NF-κB activation and subsequence up-regulation of NADPH oxidase, 2) eNOS uncoupling. AP-1, although is not directly affected by gHSA, is another target for regulating NADPH oxidase and eNOS expression in endothelial cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. A capture method based on the VC1 domain reveals new binding properties of the human receptor for advanced glycation end products (RAGE

    Directory of Open Access Journals (Sweden)

    Genny Degani

    2017-04-01

    Full Text Available The Advanced Glycation and Lipoxidation End products (AGEs and ALEs are a heterogeneous class of compounds derived from the non-enzymatic glycation or protein adduction by lipoxidation break-down products. The receptor for AGEs (RAGE is involved in the progression of chronic diseases based on persistent inflammatory state and oxidative stress. RAGE is a pattern recognition receptor (PRR and the inhibition of the interaction with its ligands or of the ligand accumulation have a potential therapeutic effect. The N-terminal domain of RAGE, the V domain, is the major site of AGEs binding and is stabilized by the adjacent C1 domain. In this study, we set up an affinity assay relying on the extremely specific biological interaction AGEs ligands have for the VC1 domain. A glycosylated form of VC1, produced in the yeast Pichia pastoris, was attached to magnetic beads and used as insoluble affinity matrix (VC1-resin. The VC1 interaction assay was employed to isolate specific VC1 binding partners from in vitro generated AGE-albumins and modifications were identified/localized by mass spectrometry analysis. Interestingly, this method also led to the isolation of ALEs produced by malondialdehyde treatment of albumins. Computational studies provided a rational-based interpretation of the contacts established by specific modified residues and amino acids of the V domain. The validation of VC1-resin in capturing AGE-albumins from complex biological mixtures such as plasma and milk, may lead to the identification of new RAGE ligands potentially involved in pro-inflammatory and pro-fibrotic responses, independently of their structures or physical properties, and without the use of any covalent derivatization process. In addition, the method can be applied to the identification of antagonists of RAGE-ligand interaction.

  4. Relationship between advanced glycation end-products with the severity of chronic heart failure in 85 patients

    Directory of Open Access Journals (Sweden)

    Amir Farhang Zand Parsa

    2013-12-01

    Full Text Available Background: Advanced glycation end-products (AGEs came up with the recent researches regarding new biomarkers for the diagnosis of heart failure. AGEs are the end products of non-enzymatic glycation and oxidation of proteins, lipids and nucleotides during Maillard biochemical reaction. Although it has been known that AGEs have a role in the pathogenesis of chronic heart failure (CHF, information regarding its role and its pathogenetic mechanism is very limited. The aim of this study was to find any relationship between AGEs with the etiology and severity of chronic heart failure.Methods: This study is a prospective cross sectional study that enrolled 85 patients with chronic heart failure. Measurement of left ventricle ejection fraction (LVEF was done by echocardiography. Blood samples were collected for measuring AGEs just before or after echocardiography assessment (in the same session. Measurement of AGEs was done by the enzyme-linked immunosorbent assay (ELISA method. The relationship between AGEs with the severity of CHF and as well as the etiology of CHF were evaluated via SPSS-15.Results: Of 85 patients 48 (56.5% patients were male and 37 (43.5% were female; Mean±SD of their ages was 55.8±13.4 years old (ranges from 27 to 84 years. Correlation coefficient between LVEF and AGEs was 0.269 (P=0.013. Mean of AGEs in patients with and without ischemic etiology of their heart failure were 16.8±9.8µg/ml and 11.6±7.3 µg/ml, respectively. Although trend was in favor of ischemic heart failure, the difference between two groups was not statistically significant (P= 0.141.Conclusion: According to this study the rate of AGES could be helpful in the diagnosis and assessment of severity of CHF. Based on our findings, higher blood levels of AGEs in the ischemic CHF cases, also it could be concluded that in the future this marker may be used for etiologic differentiation of heart failure syndrome.

  5. A highly sensitive non-enzymatic glucose sensor based on nickel and multi-walled carbon nanotubes nanohybrid films fabricated by one-step co-electrodeposition in ionic liquids

    International Nuclear Information System (INIS)

    Sun Aili; Zheng Jianbin; Sheng Qinglin

    2012-01-01

    Graphical abstract: Cyclic voltammograms of Ni–MWNTs/GCE at different concentrations of glucose. Highlights: ► Ni –MWNT nanohybrid film was successfully synthesized and characterized by SEM and EDS. ► The mechanism of glucose at Ni –MWNT nanohybrid film was evaluated and the upper glucose concentration limit produced a linear response of 17.5 mM. ► Simple of preparation and good analytical response made nanohybrid films a promising sensor material for non-enzymatic glucose sensing in routine analysis. - Abstract: In this paper, nickel was combined with multi-walled carbon nanotubes (Ni–MWNTs) to fabricate nanohybrid films on a conventional glassy carbon electrode using simultaneous electrodeposition of NiCl 2 and the MWNTs in ionic liquids (ILs). The morphologies and elemental compositions of the nanohybrid films were investigated with scanning electron microscopy and energy dispersive spectroscopy. A novel non-enzymatic glucose sensor based on the Ni–MWNT nanohybrid film-modified glassy carbon electrode was described, and its electrochemical behaviors were investigated. The proposed sensor exhibited high electrocatalytic activity and good response to glucose. Under optimal conditions, the sensor showed high sensitivity (67.2 μA mM −1 cm −2 ), rapid response time (<2 s) and a low detection limit (0.89 μM; signal/noise ratio of 3). In particular, the upper glucose concentration limit produced a linear response of 17.5 mM. Thus, the Ni–MWNT nanohybrid films represent promising sensor materials for non-enzymatic glucose sensing in routine analyses.

  6. High-performance non-enzymatic catalysts based on 3D hierarchical hollow porous Co3O4nanododecahedras in situ decorated on carbon nanotubes for glucose detection and biofuel cell application.

    Science.gov (United States)

    Wang, Shiyue; Zhang, Xiaohua; Huang, Junlin; Chen, Jinhua

    2018-03-01

    In this work, high-performance non-enzymatic catalysts based on 3D hierarchical hollow porous Co 3 O 4 nanododecahedras in situ decorated on carbon nanotubes (3D Co 3 O 4 -HPND/CNTs) were successfully prepared via direct carbonizing metal-organic framework-67 in situ grown on carbon nanotubes. The morphology, microstructure, and composite of 3D Co 3 O 4 -HPND/CNTs were characterized by scanning electron microscopy, transmission electron microscopy, micropore and chemisorption analyzer, and X-ray diffraction. The electrochemical characterizations indicated that 3D Co 3 O 4 -HPND/CNTs present considerably catalytic activity toward glucose oxidation and could be promising for constructing high-performance electrochemical non-enzymatic glucose sensors and glucose/O 2 biofuel cell. When used for non-enzymatic glucose detection, the 3D Co 3 O 4 -HPND/CNTs modified glassy carbon electrode (3D Co 3 O 4 -HPND/CNTs/GCE) exhibited excellent analytical performance with high sensitivity (22.21 mA mM -1  cm -2 ), low detection limit of 0.35 μM (S/N = 3), fast response (less than 5 s) and good stability. On the other hand, when the 3D Co 3 O 4 -HPND/CNTs/GCE worked as an anode of a biofuel cell, a maximum power density of 210 μW cm -2 at 0.15 V could be obtained, and the open circuit potential was 0.68 V. The attractive 3D hierarchical porous structural features, the large surface area, and the excellent conductivity based on the continuous and effective electron transport network in 3D Co 3 O 4 -HPND/CNTs endow 3D Co 3 O 4 -HPND/CNTs with the enhanced electrochemical performance and promising applications in electrochemical sensing, biofuel cell, and other energy storage and conversion devices such as supercapacitor. Graphical abstract High-performance non-enzymatic catalysts for enzymeless glucose sensing and biofuel cell based on 3D hierarchical hollow porous Co 3 O 4 nanododecahedras anchored on carbon nanotubes were successfully prepared via direct carbonizing

  7. Effects of Glycated Whey Protein Concentrate on Pro-inflammatory Cytokine Expression and Phagocytic Activity in RAW264.7 Macrophages.

    Science.gov (United States)

    Chun, Su-Hyun; Lee, Hyun Ah; Lee, Keon Bong; Kim, Sae Hun; Park, Kun-Young; Lee, Kwang-Won

    2016-01-01

    The aim of this study was to determine the stimulatory effects of Maillard reaction, a non-enzymatic browning reaction on the expression of pro-inflammatory cytokines and phagocytic activity induced by whey protein concentrate (WPC). Glycated WPC (G-WPC) was prepared by a reaction between WPC and the lactose it contained. The fluorescence intensity of G-WPC dramatically increased after one day, and high molecular weight complexes formed via the Maillard reaction were also observed in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles. G-WPC demonstrated immunomodulatory effects, including stimulation of increased nitric oxide production and cytokine expressions (i.e., tumor necrosis factor-α, interleukin (IL)-1β, and IL-6), compared to WPC. Furthermore, the phagocytic activity of RAW264.7 cells was significantly increased upon treatment with G-WPC, compared to WPC. Therefore, we suggest that G-WPC can be utilized as an improved dietary source for providing immune modulating activity.

  8. Effects of thyroid status on glycated hemoglobin

    Directory of Open Access Journals (Sweden)

    Rana Bhattacharjee

    2017-01-01

    Full Text Available Introduction: Glycated hemoglobin (HbA1c can be altered in different conditions. We hypothesize that HbA1c levels may change due to altered thyroid status, possibly due to changes in red blood cell (RBC turnover. Objectives: The objective of this study was to determine the effects of altered thyroid status on HbA1c levels in individuals without diabetes, with overt hyper- and hypo-thyroidism, and if present, whether such changes in HbA1c are reversed after achieving euthyroid state. Methods: Euglycemic individuals with overt hypo- or hyper-thyroidism were selected. Age- and sex-matched controls were recruited. Baseline HbA1c and reticulocyte counts (for estimation of RBC turnover were estimated in all the patients and compared. Thereafter, stable euthyroidism was achieved in a randomly selected subgroup and HbA1c and reticulocyte count was reassessed. HbA1c values and reticulocyte counts were compared with baseline in both the groups. Results: Hb A1c in patients initially selected was found to be significantly higher in hypothyroid group. HbA1c values in hyperthyroid patients were not significantly different from controls. HbA1c reduction and rise in reticulocyte count were significant in hypothyroid group following treatment without significant change in glucose level. Hb A1c did not change significantly following treatment in hyperthyroid group. The reticulocyte count, however, decreased significantly. Conclusion: Baseline HbA1c levels were found to be significantly higher in hypothyroid patients, which reduced significantly after achievement of euthyroidism without any change in glucose levels. Significant baseline or posttreatment change was not observed in hyperthyroid patients. Our study suggests that we should be cautious while interpreting HbA1c data in patients with hypothyroidism.

  9. Peptide dendrimers

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2005-01-01

    Roč. 11, - (2005), 757-788 ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005

  10. Inhibition of Nonenzymatic Protein Glycation by Pomegranate and Other Fruit Juices

    Science.gov (United States)

    Dorsey, Pamela Garner; Greenspan, Phillip

    2014-01-01

    Abstract The nonenzymatic glycation of proteins and the formation of advanced glycation endproducts in diabetes leads to the crosslinking of proteins and disease complications. Our study sought to demonstrate the effect of commonly consumed juices (pomegranate, cranberry, black cherry, pineapple, apple, and Concord grape) on the fructose-mediated glycation of albumin. Albumin glycation decreased by 98% in the presence of 10 μL of pomegranate juice/mL; other juices inhibited glycation by only 20%. Pomegranate juice produced the greatest inhibition on protein glycation when incubated at both the same phenolic concentration and the same antioxidant potential. Both punicalagin and ellagic acid significantly inhibited the glycation of albumin by ∼90% at 5 μg/mL. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed that pomegranate, but not apple juice, protected albumin from modification. These results demonstrate that pomegranate juice and two of its major constituents are potent inhibitors of fructose-mediated protein glycation. PMID:24433074

  11. Advanced glycation end products in the skin are enhanced in COPD

    NARCIS (Netherlands)

    Hoonhorst, Susan J. M.; Loi, Adele T. Lo Tam; Hartman, Jorine E.; Telenga, Eef D.; van den Berge, Maarten; Koenderman, Leo; Lammers, Jan Willem J.; Boezen, H. Marike; Postma, Dirkje S.; ten Hacken, Nick H. T.

    Background. Cigarette smoking is the main cause of chronic obstructive pulmonary disease (COPD) inducing oxidative stress and local tissue injury, resulting in pulmonary inflammation. Advanced glycation end products (AGEs) are produced by glycation and oxidation processes and their formation is

  12. Characterization of anti-advanced glycation end product antibodies to nonenzymatically lysine-derived and arginine-derived glycated products.

    Science.gov (United States)

    Choi, Yeong-Gon; Lim, Sabina

    2009-01-01

    N(epsilon)-(carboxymethyl)lysine (CML) and N(epsilon)-(carboxyethyl)lysine (CEL) termed advanced glycation end products (AGEs) are known to be produced by nonenzymatic glycation between bovine serum albumin (BSA) and D-glucose. This study is to characterize the immunoreactivity of anti-AGE antibodies including anti-CML and anti-CEL antibodies. Using AGE-modified BSA (AGE-BSA) as an immunogen, a polyclonal anti-AGE immunoglobulin G (IgG) was produced. The anti-AGE IgG could strongly detect AGEs formed on BSA, at least in part, AGEs produced on both residues Lys and Arg due to its immunoreaction with Lys-derived and Arg-derived AGEs produced by NaCNBH(3), a reducing agent, in amino acid glycation analysis, but the pre-immune serum could not. As the anti-CML antibody could also strongly react with AGE-BSA, this suggests that CML is a major nonenzymatically glycated product cross-linked to BSA. Furthermore, CEL is associated with distinguishable polymerization of BSA from CML polymerization of BSA, though weaker than CML and was not produced by Lys glycation analysis. These results indicate that the anti-AGE antibody is effective for detecting both Lys-derived and Arg-derived AGEs, and CML and CEL distinctively polymerize albumin as major AGEs present on AGE-BSA.

  13. Glycated Albumin versus Glycated Hemoglobin as a Glycemic Indicator in Diabetic Patients on Peritoneal Dialysis

    Directory of Open Access Journals (Sweden)

    Hiroki Kobayashi

    2016-04-01

    Full Text Available Compared with glycated hemoglobin (HbA1c, glycated albumin (GA is superior in estimating glycemic control in diabetic patients on hemodialysis (HD. However, the better index for assessment of glycemic control in diabetic patients on peritoneal dialysis (PD and the impact of protein loss on GA are unknown. Twenty diabetic patients on HD were matched by age, sex, and baseline postprandial plasma glucose (PG levels to 20 PD patients. PG, HbA1c, GA, and serum albumin levels were measured for six months. Protein loss in PD patients was estimated by measuring the protein concentration in the peritoneal dialysate and by 24 h urine collection. Although PG and HbA1c did not differ significantly between the groups, the PD group had significantly lower GA (17.8% versus 20.8%, p < 0.001 and GA/HbA1c ratio (2.95% versus 3.45%, p < 0.0001 than the HD group. Although the PG level correlated significantly with the GA levels in both groups, it was not correlated with the HbA1c levels in both groups. HbA1c level was negatively associated with erythropoiesis-stimulating agent (ESA dose in both groups, whereas GA was not significantly associated with serum albumin, hemoglobin concentration, ESA dose, and protein loss. Multiple regression analysis identified GA as the only independent factor associated with PG in PD patients. Our results suggested that GA was not significantly associated with protein loss, hemoglobin, serum albumin, and ESA dose. Although GA might underestimate glycemic status, it provided a significantly better measure for estimating glycemic control than HbA1c, even in PD patients.

  14. Effect of Temperature on Tolbutamide Binding to Glycated Serum Albumin

    Directory of Open Access Journals (Sweden)

    Agnieszka Szkudlarek

    2017-03-01

    Full Text Available Glycation process occurs in protein and becomes more pronounced in diabetes when an increased amount of reducing sugar is present in bloodstream. Glycation of protein may cause conformational changes resulting in the alterations of its binding properties even though they occur at a distance from the binding sites. The changes in protein properties could be related to several pathological consequences such as diabetic and nondiabetic cardiovascular diseases, cataract, renal dysfunction and Alzheimer’s disease. The experiment was designed to test the impact of glycation process on sulfonylurea drug tolbutamide-albumin binding under physiological (T = 309 K and inflammatory (T = 311 K and T = 313 K states using fluorescence and UV-VIS spectroscopies. It was found in fluorescence analysis experiments that the modification of serum albumin in tryptophanyl and tyrosyl residues environment may affect the tolbutamide (TB binding to albumin in subdomain IIA and/or IIIA (Sudlow’s site I and/or II, and also in subdomains IB and IIB. We estimated the binding of tolbutamide to albumin described by a mixed nature of interaction (specific and nonspecific. The association constants Ka (L∙mol−1 for tolbutamide at its high affinity sites on non-glycated albumin were in the range of 1.98–7.88 × 104 L∙mol−1 (λex = 275 nm, 1.20–1.64 × 104 L∙mol−1 (λex = 295 nm and decreased to 1.24–0.42 × 104 L∙mol−1 at λex = 275 nm (T = 309 K and T = 311 K and increased to 2.79 × 104 L∙mol−1 at λex = 275 nm (T = 313 K and to 4.43–6.61 × 104 L∙mol−1 at λex = 295 nm due to the glycation process. Temperature dependence suggests the important role of van der Waals forces and hydrogen bonding in hydrophobic interactions between tolbutamide and both glycated and non-glycated albumin. We concluded that the changes in the environment of TB binding of albumin in subdomain IIA and/or IIIA as well as in subdomains IB and IIB influence on

  15. Potent Protein Glycation Inhibition of Plantagoside in Plantago major Seeds

    Directory of Open Access Journals (Sweden)

    Nobuyasu Matsuura

    2014-01-01

    Full Text Available Plantagoside (5,7,4′,5′-tetrahydroxyflavanone-3′-O-glucoside and its aglycone (5,7,3′,4′,5′-pentahydroxyflavanone, isolated from a 50% ethanol extract of Plantago major seeds (Plantaginaceae, were established to be potent inhibitors of the Maillard reaction. These compounds also inhibited the formation of advanced glycation end products in proteins in physiological conditions and inhibited protein cross-linking glycation. These results indicate that P. major seeds have potential therapeutic applications in the prevention of diabetic complications.

  16. Glycation inhibitors extend yeast chronological lifespan by reducing advanced glycation end products and by back regulation of proteins involved in mitochondrial respiration.

    Science.gov (United States)

    Kazi, Rubina S; Banarjee, Reema M; Deshmukh, Arati B; Patil, Gouri V; Jagadeeshaprasad, Mashanipalya G; Kulkarni, Mahesh J

    2017-03-06

    Advanced Glycation End products (AGEs) are implicated in aging process. Thus, reducing AGEs by using glycation inhibitors may help in attenuating the aging process. In this study using Saccharomyces cerevisiae yeast system, we show that Aminoguanidine (AMG), a well-known glycation inhibitor, decreases the AGE modification of proteins in non-calorie restriction (NR) (2% glucose) and extends chronological lifespan (CLS) similar to that of calorie restriction (CR) condition (0.5% glucose). Proteomic analysis revealed that AMG back regulates the expression of differentially expressed proteins especially those involved in mitochondrial respiration in NR condition, suggesting that it switches metabolism from fermentation to respiration, mimicking CR. AMG induced back regulation of differentially expressed proteins could be possibly due to its chemical effect or indirectly by glycation inhibition. To delineate this, Metformin (MET), a structural analog of AMG and a mild glycation inhibitor and Hydralazine (HYD), another potent glycation inhibitor but not structural analog of AMG were used. HYD was more effective than MET in mimicking AMG suggesting that glycation inhibition was responsible for restoration of differentially expressed proteins. Thus glycation inhibitors particularly AMG, HYD and MET extend yeast CLS by reducing AGEs, modulating the expression of proteins involved in mitochondrial respiration and possibly by scavenging glucose. This study reports the role of glycation in aging process. In the non-caloric restriction condition, carbohydrates such as glucose promote protein glycation and reduce CLS. While, the inhibitors of glycation such as AMG, HYD, MET mimic the caloric restriction condition by back regulating deregulated proteins involved in mitochondrial respiration which could facilitate shift of metabolism from fermentation to respiration and extend yeast CLS. These findings suggest that glycation inhibitors can be potential molecules that can be used

  17. Relationship Between Glycated Haemoglobin and Body Mass Index ...

    African Journals Online (AJOL)

    Blood pressure, Height, Weight were all measured and body mass index (BMI) calculated as weight (in kilograms) divided by height (in meters squared). Glycated haemoglobin was estimated using the ion exchange chromatography method. Result: A total of 100 healthy subjects, 50 males and 50 females, ages ranging ...

  18. 173 original article glycated haemoglobin levels in patients

    African Journals Online (AJOL)

    boaz

    Keywords: Diabetes mellitus, Glycaemic change, Glycated haemoglobin, Multidrug resistant tuberculosis therapy. L'HÉMOGLOBINE GLYQUÉE CHEZ LES PATIENTS PRÉSENTANT UNE INFECTION À LA TUBERCULOSE. MULTIRÉSISTANTE AU COURS DES 6 PREMIERS MOIS DE TRAITEMENT. Akinlade KS1, Arinola ...

  19. Effects of advanced glycation end-products (AGEs) on skin ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-06-21

    Jun 21, 2012 ... Abbreviations: AGEs, Glycation end-products; SD, Sprague-. Dawley; STZ, streptozotocin; EGF, epidermal growth factor; NF-. kB, nuclear factor-kappa B. result in significant morbidity. Impaired wound healing is a common vascular complication of diabetes mellitus and constitutes a major clinical problem ...

  20. Relationship between glycated Haemoglobin and glucose levels in ...

    African Journals Online (AJOL)

    Relationship between glycated Haemoglobin and glucose levels in adult healthy and diabeticNigerians in Benin Metropolis. ... haemoglobin correlated with fasting plasma glucose in the population studied, it may be used as a fairly accurate tool in assessing glycaemic control and monitoring treatment in diabetes mellitus.

  1. Glycation promotes the formation of genotoxic aggregates in glucose oxidase.

    Science.gov (United States)

    Khan, Taqi Ahmed; Amani, Samreen; Naeem, Aabgeena

    2012-09-01

    This study investigates the effect of pentose sugars (ribose and arabinose) on the structural and chemical modifications in glucose oxidase (GOD) as well as genotoxic potential of this modified form. An intermediate state of GOD was observed on day 12 of incubation having CD minima peaks at 222 and 208 nm, characteristic of α-helix and a few tertiary contacts with altered tryptophan environment and high ANS binding. All these features indicate the existence of molten globule state of the GOD with ribose and arabinose on day 12. GOD on day 15 of incubation forms β structures as revealed by CD and FTIR which may be due to its aggregation. Furthermore, GOD on day 15 showed a remarkable increase in Thioflavin T fluorescence at 485 nm. Comet assay of lymphocytes and plasmid nicking assay in presence of glycated GOD show DNA damage which confirmed the genotoxicity of advance glycated end products. Hence, our study suggests that glycated GOD results in the formation of aggregates and the advanced glycated end products, which are genotoxic in nature.

  2. Advanced glycation endproducts in food and their effects on health

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe; Hedegaard, Rikke Susanne Vingborg; Andersen, Jeanette Marker

    2013-01-01

    Advanced glycation endproducts (AGEs) form by Maillard-reactions after initial binding of aldehydes with amines or amides in heated foods or in living organisms. The mechanisms of formation may include ionic as well as oxidative and radical pathways. The reactions may proceed within proteins...

  3. The plasma level of soluble receptor for advanced glycation end ...

    African Journals Online (AJOL)

    The plasma level of soluble receptor for advanced glycation end products in systemic lupus erythematosus patients and its relation to disease activity. Anna Nashaat Abou-Raya, Maher Abdel Nabi Kamel, Eman Abdel Ghani Sayed, Ahmed Abdel Hamid El-Sharkawy ...

  4. Inhibition of glucose- and fructose-mediated protein glycation by infusions and ethanolic extracts of ten culinary herbs and spices

    Directory of Open Access Journals (Sweden)

    Jugjeet Singh Ramkissoon

    2016-06-01

    Conclusions: The higher rate of fluorescence generation by fructation suggests that glycation by fructose deserves much attention as a glycating agent. Data herein showed that the extracts inhibited GMG and FMG. Thus, these edible plants could be a natural source of antioxidants and anti-glycation agent for preventing advanced glycation end-products-mediated complications.

  5. A study on human serum albumin influence on glycation of fibrinogen

    Energy Technology Data Exchange (ETDEWEB)

    Kielmas, Martyna; Szewczuk, Zbigniew; Stefanowicz, Piotr, E-mail: Piotr.stefanowicz@chem.uni.wroc.pl

    2013-09-13

    Highlights: •The glycation of fibrinogen was investigated by isotopic labeling method. •The potential glycation sites in fibrinogen were identified. •Human serum albumin (HSA) inhibits the glycation of fibrinogen. •The effect of HSA on fibrinogen glycation is sequence-dependent. -- Abstract: Although in vivo glycation proceeds in complex mixture of proteins, previous studies did not take in consideration the influence of protein–protein interaction on Maillard reaction. The aim of our study was to test the influence of human serum albumin (HSA) on glycation of fibrinogen. The isotopic labeling using [{sup 13}C{sub 6}] glucose combined with LC-MS were applied as tool for identification possible glycation sites in fibrinogen and for evaluation the effect of HSA on the glycation level of selected amino acids in fibrinogen. The obtained data indicate that the addition of HSA protects the fibrinogen from glycation. The level of glycation in presence of HSA is reduced by 30–60% and depends on the location of glycated residue in sequence of protein.

  6. A study on human serum albumin influence on glycation of fibrinogen

    International Nuclear Information System (INIS)

    Kielmas, Martyna; Szewczuk, Zbigniew; Stefanowicz, Piotr

    2013-01-01

    Highlights: •The glycation of fibrinogen was investigated by isotopic labeling method. •The potential glycation sites in fibrinogen were identified. •Human serum albumin (HSA) inhibits the glycation of fibrinogen. •The effect of HSA on fibrinogen glycation is sequence-dependent. -- Abstract: Although in vivo glycation proceeds in complex mixture of proteins, previous studies did not take in consideration the influence of protein–protein interaction on Maillard reaction. The aim of our study was to test the influence of human serum albumin (HSA) on glycation of fibrinogen. The isotopic labeling using [ 13 C 6 ] glucose combined with LC-MS were applied as tool for identification possible glycation sites in fibrinogen and for evaluation the effect of HSA on the glycation level of selected amino acids in fibrinogen. The obtained data indicate that the addition of HSA protects the fibrinogen from glycation. The level of glycation in presence of HSA is reduced by 30–60% and depends on the location of glycated residue in sequence of protein

  7. Non-enzymatic posttranslational modifications of bovine serum albumin by oxo-compounds investigated by high-performance liquid chromatography–mass spectrometry and capillary zone electrophoresis–mass spektrometry

    Czech Academy of Sciences Publication Activity Database

    Zmatlíková, Zdeňka; Sedláková, Pavla; Lacinová, Kateřina; Eckhardt, Adam; Pataridis, Statis; Mikšík, Ivan

    2010-01-01

    Roč. 1217, č. 51 (2010), s. 8009-8015 ISSN 0021-9673 R&D Projects: GA MŠk(CZ) 1M0510; GA ČR(CZ) GA203/08/1428; GA ČR(CZ) GA203/09/0675 Institutional research plan: CEZ:AV0Z50110509 Keywords : glycation * HPLC-MS * CE-MS Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.194, year: 2010

  8. Influence of storage and heating on protein glycation levels of processed lactose-free and regular bovine milk products.

    Science.gov (United States)

    Milkovska-Stamenova, Sanja; Hoffmann, Ralf

    2017-04-15

    Thermal treatment preserves the microbiological safety of milk, but also induces Maillard reactions modifying for example proteins. The purpose of this study was evaluating the influence of consumer behaviors (storage and heating) on protein glycation degrees in bovine milk products. Lactosylation and hexosylation sites were identified in ultra-high temperature (UHT), lactose-free pasteurized, and lactose-free UHT milk (ULF) and infant formula (IF) using tandem mass spectrometry (electron transfer dissociation). Overall, 303 lactosylated and 199 hexosylated peptides were identified corresponding to 170 lactosylation (31 proteins) and 117 hexosylation sites (25 proteins). In quantitative terms, storage increased lactosylation up to fourfold in UHT and IF and hexosylation up to elevenfold in ULF and threefold in IF. These levels increased additionally twofold when the stored samples were heated (40°C). In conclusion, storage and heating appear to influence protein glycation levels in milk at similar or even higher degrees than industrial processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Targeted reduction of advanced glycation improves renal function in obesity

    DEFF Research Database (Denmark)

    Harcourt, Brooke E; Sourris, Karly C; Coughlan, Melinda T

    2011-01-01

    Obesity is highly prevalent in Western populations and is considered a risk factor for the development of renal impairment. Interventions that reduce the tissue burden of advanced glycation end-products (AGEs) have shown promise in stemming the progression of chronic disease. Here we tested...... if treatments that lower tissue AGE burden in patients and mice would improve obesity-related renal dysfunction. Overweight and obese individuals (body mass index (BMI) 26-39¿kg/m(2)) were recruited to a randomized, crossover clinical trial involving 2 weeks each on a low- and a high-AGE-containing diet. Renal...... function and an inflammatory profile (monocyte chemoattractant protein-1 (MCP-1) and macrophage migration inhibitory factor (MIF)) were improved following the low-AGE diet. Mechanisms of advanced glycation-related renal damage were investigated in a mouse model of obesity using the AGE...

  10. Variations in glutamine deamidation for a Châtelperronian bone assemblage as measured by peptide mass fingerprinting of collagen

    DEFF Research Database (Denmark)

    Welker, Frido; Soressi, Marie A.; Roussel, Morgan

    2017-01-01

    AbstractPeptide mass fingerprinting of bone collagen (ZooMS) has previously been proposed as a method to calculate the extent of the non-enzymatic degradation of glutamine into glutamic acid (deamidation). Temporal and spatial variation of glutamine deamidation at a single site, however, has...... not been investigated. Here we apply ZooMS screening of Châtelperronian and Early Holocene bone specimens from Quinçay, France, to explore temporal and spatial variation in glutamine deamidation. Our results indicate that chronological resolution is low, while spatial variation is high. Nevertheless, our...

  11. Spectroscopic studies on native proteins, glycated and inhibited nonenzymatically

    International Nuclear Information System (INIS)

    Gil, H; Otero, V; Contreras, S

    1995-01-01

    The nonenzymatic glucation is an irreversible process whose speed depends on the concentration reducer sugar in plasma. The glycated albumins is higher in diabetic people. Up to now, this has been indicated as an important mechanism in the pathology of the the secondary complications associated with diabetes and the normal aging. Recently a lot of interest has been focused on the search of certain compounds (inhibitors) to prevent the glucation and / or the formation of ending products of advanced glucation, AGE. The reaction of glucose with the human albumin and γ globulins and the effects of acid acetylsalicylic and ascorbic acid were studied. The proteins were incubated with glucose in absence and in presence of inhibitors for one month. The solutions were dialysed and then lyophilizated. The absorption spectra were taken for native proteins, glycated and inhibited (2 mg/ml) in phosphate 10 mM buffer, p H 7.3. It is observed that the spectra of the acetylate proteins and native proteins are practically same. This can be interpreted as an inhibitor effect of acid acetylsalicylic on glucation. In all the observed cases the glycated proteins absorb more than the native ones and they present a line toward the visible region. The ascorbic acid absorbs below the native proteins and it doesn't present the same characteristics. The increase and / or the decrease in the absorption picks can be associated with environmental changes affecting the groups involved in the absorption process [es

  12. Multicenter evaluation of an enzymatic method for glycated albumin.

    Science.gov (United States)

    Paleari, Renata; Bonetti, Graziella; Callà, Cinzia; Carta, Mariarosa; Ceriotti, Ferruccio; Di Gaetano, Nicola; Ferri, Marilisa; Guerra, Elena; Lavalle, Gabriella; Cascio, Claudia Lo; Martino, Francesca Gabriela; Montagnana, Martina; Moretti, Marco; Santini, Gabriele; Scribano, Donata; Testa, Roberto; Vero, Anna; Mosca, Andrea

    2017-06-01

    The use of glycated albumin (GA) has been proposed as an additional glycemic control marker particularly useful in intermediate-term monitoring and in situation when HbA 1c test is not reliable. We have performed the first multicenter evaluation of the analytical performance of the enzymatic method quantILab Glycated Albumin assay implemented on the most widely used clinical chemistry analyzers (i.e. Abbott Architect C8000, Beckman Coulter AU 480 and 680, Roche Cobas C6000, Siemens ADVIA 2400 and 2400 XPT). The repeatability of the GA measurement (expressed as CV, %) implemented in the participating centers ranged between 0.9% and 1.2%. The within-laboratory CVs ranged between 1.2% and 1.6%. A good alignment between laboratories was found, with correlation coefficients from 0.996 to 0.998. Linearity was confirmed in the range from 7.6 to 84.7%. The new enzymatic method for glycated albumin evaluated by our investigation is suitable for clinical use. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Ovalbumin with Glycated Carboxyl Groups Shows Membrane-Damaging Activity

    Directory of Open Access Journals (Sweden)

    Ching-Chia Tang

    2017-02-01

    Full Text Available The aim of the present study was to investigate whether glycated ovalbumin (OVA showed novel activity at the lipid-water interface. Mannosylated OVA (Man-OVA was prepared by modification of the carboxyl groups with p-aminophenyl α-dextro (d-mannopyranoside. An increase in the number of modified carboxyl groups increased the membrane-damaging activity of Man-OVA on cell membrane-mimicking vesicles, whereas OVA did not induce membrane permeability in the tested phospholipid vesicles. The glycation of carboxyl groups caused a notable change in the gross conformation of OVA. Moreover, owing to their spatial positions, the Trp residues in Man-OVA were more exposed, unlike those in OVA. Fluorescence quenching studies suggested that the Trp residues in Man-OVA were located on the interface binds with the lipid vesicles, and their microenvironment was abundant in positively charged residues. Although OVA and Man-OVA showed a similar binding affinity for lipid vesicles, the lipid-interacting feature of Man-OVA was distinct from that of OVA. Chemical modification studies revealed that Lys and Arg residues, but not Trp residues, played a crucial role in the membrane-damaging activity of Man-OVA. Taken together, our data suggest that glycation of carboxyl groups causes changes in the structural properties and membrane-interacting features of OVA, generating OVA with membrane-perturbing activities at the lipid-water interface.

  14. SERUM MAGNESIUM, LIPID PROFILE AND GLYCATED HAEMOGLOBIN IN DIABETIC RETINOPATHY

    Directory of Open Access Journals (Sweden)

    Sunanda Vusikala

    2016-07-01

    Full Text Available BACKGROUND Diabetic retinopathy is one of the important microvascular complications of diabetes mellitus of long duration. Alterations in trace metals like magnesium and lipid profile was observed in diabetic retinopathy with hyperglycaemic status. AIM The study was taken up to assess the role of magnesium, lipid profile and glycated haemoglobin in diabetic retinopathy. MATERIALS AND METHODS A total of 80 subjects between 40-65 years were included in the study. Group 1 includes 20 age and sex matched healthy controls. Group 2 includes 30 cases of Diabetes mellitus without retinopathy. Group 3 includes 30 cases of Diabetes mellitus with retinopathy. RESULTS Magnesium was found to be significantly low in the diabetic group with retinopathy. Serum cholesterol and triglycerides were significantly elevated in the diabetic group with retinopathy. Fasting and Postprandial plasma glucose and glycated haemoglobin (HbA1c levels confirmed the glycaemic status of each of the groups. CONCLUSIONS Hypomagnesemia, hypercholesterolaemia, hypertriglyceridemia was observed in diabetic retinopathy along with increased levels of glycated haemoglobin in our study.

  15. Targeted reduction of advanced glycation improves renal function in obesity.

    Science.gov (United States)

    Harcourt, Brooke E; Sourris, Karly C; Coughlan, Melinda T; Walker, Karen Z; Dougherty, Sonia L; Andrikopoulos, Sofianos; Morley, Amy L; Thallas-Bonke, Vicki; Chand, Vibhasha; Penfold, Sally A; de Courten, Maximilian P J; Thomas, Merlin C; Kingwell, Bronwyn A; Bierhaus, Angelika; Cooper, Mark E; de Courten, Barbora; Forbes, Josephine M

    2011-07-01

    Obesity is highly prevalent in Western populations and is considered a risk factor for the development of renal impairment. Interventions that reduce the tissue burden of advanced glycation end-products (AGEs) have shown promise in stemming the progression of chronic disease. Here we tested if treatments that lower tissue AGE burden in patients and mice would improve obesity-related renal dysfunction. Overweight and obese individuals (body mass index (BMI) 26-39 kg/m(2)) were recruited to a randomized, crossover clinical trial involving 2 weeks each on a low- and a high-AGE-containing diet. Renal function and an inflammatory profile (monocyte chemoattractant protein-1 (MCP-1) and macrophage migration inhibitory factor (MIF)) were improved following the low-AGE diet. Mechanisms of advanced glycation-related renal damage were investigated in a mouse model of obesity using the AGE-lowering pharmaceutical, alagebrium, and mice in which the receptor for AGE (RAGE) was deleted. Obesity, resulting from a diet high in both fat and AGE, caused renal impairment; however, treatment of the RAGE knockout mice with alagebrium improved urinary albumin excretion, creatinine clearance, the inflammatory profile, and renal oxidative stress. Alagebrium treatment, however, resulted in decreased weight gain and improved glycemic control compared with wild-type mice on a high-fat Western diet. Thus, targeted reduction of the advanced glycation pathway improved renal function in obesity.

  16. Cross-Linking in Collagen by Nonenzymatic Glycation Increases the Matrix Stiffness in Rabbit Achilles Tendon

    OpenAIRE

    Reddy, G. Kesava

    2004-01-01

    Nonenzymatic glycation of connective tissue matrix proteins is a major contributor to the pathology of diabetes and aging. Previously the author and colleagues have shown that nonenzymatic glycation significantly enhances the matrix stability in the Achilles tendon (Reddy et al., 2002, Arch. Biochem. Biophys., 399, 174–180). The present study was designed to gain further insight into glycation-induced collagen cross-linking and its relationship to matrix stiffness in the rabbit Achilles tendo...

  17. Calorimetric investigation of diclofenac drug binding to a panel of moderately glycated serum albumins.

    Science.gov (United States)

    Indurthi, Venkata S K; Leclerc, Estelle; Vetter, Stefan W

    2014-08-01

    Glycation alters the drug binding properties of serum proteins and could affect free drug concentrations in diabetic patients with elevated glycation levels. We investigated the effect of bovine serum albumin glycation by eight physiologically relevant glycation reagents (glucose, ribose, carboxymethyllysine, acetoin, methylglyoxal, glyceraldehyde, diacetyl and glycolaldehyde) on diclofenac drug binding. We used this non-steroidal anti-inflammatory drug diclofenac as a paradigm for acidic drugs with high serum binding and because of its potential cardiovascular risks in diabetic patients. Isothermal titration calorimetry showed that glycation reduced the binding affinity Ka of serum albumin and diclofenac 2 to 6-fold by reducing structural rigidity of albumin. Glycation affected the number of drug binding sites in a glycation reagent dependent manner and lead to a 25% decrease for most reagent, expect for ribose, with decreased by 60% and for the CML-modification, increased the number of binding sites by 60%. Using isothermal titration calorimetry and differential scanning calorimetry we derived the complete thermodynamic characterization of diclofenac binding to all glycated BSA samples. Our results suggest that glycation in diabetic patients could significantly alter the pharmacokinetics of the widely used over-the-counter NSDAI drug diclofenac and with possibly negative implications for patients. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Inhibition of glycation of albumin and hemoglobin by acetylation in vitro and in vivo.

    Science.gov (United States)

    Rendell, M; Nierenberg, J; Brannan, C; Valentine, J L; Stephen, P M; Dodds, S; Mercer, P; Smith, P K; Walder, J

    1986-10-01

    Aspirin (acetylsalicylic acid or ASA) is known to inhibit glycosylation (glycation) of albumin in vitro. The mechanism has been presumed to be acetylation, but this has never been validated. The new affinity aminophenylboronic acid procedure for determination of glycosylated albumin was used to demonstrate inhibition of glycosylation by aspirin. ASA, but not salicylic acid, inhibited glycation. The inhibition of glycation by equimolar acetic anhydride was greater than that by ASA. Pretreatment of albumin with ASA in the absence of glucose demonstrated that inhibition was extremely rapid, occurring in a matter of minutes. However, the inhibition by ASA could not be prevented by massive acceleration of glycation induced by borohydride reduction. Glycation of hemoglobin was also inhibited by ASA, but the dose requirement was considerably higher. Various analogues of ASA were evaluated for inhibition of glycation. Only acetyl-5-ethylsalicylic acid was more effective than ASA in inhibiting albumin glycation. None of these agents was more potent than ASA in inhibiting glycation of hemoglobin. ASA was fed to diabetic rats in a long-term experiment. Glycohemoglobin and glycoalbumin levels were decreased by ASA administration. We conclude that ASA inhibits glycation by a very rapid acetylation process. This process is apparently quite selective in terms of the protein involved, presumably because of the local environment of affected lysine groups. The phenomenon can be produced in vivo by administration of ASA.

  19. Comparative study of nitro blue tetrazolium (NBT) reduction method for estimation of glycated haemoglobin with glycated HbA1c estimated on DCA2000+analyzer (immunoagglutination inhibition).

    Science.gov (United States)

    Sahu, Ashok; Gupta, Trapti; Sarkar, Purnima Dey

    2010-01-01

    Glycated haemoglobin is a diagnostic tool, used for the monitoring of the glycemic status among diabetic patients. The present study is designed to compare and correlate modified NBT reduction method for the estimation of Glycated protein (Glycated Haemoglobin) with HbA1C estimated on DCA+2000Analyzer. Glycated protein reduces Nitro Blue Tetrazolium (NBT) reagent in alkaline medium to tetrazinolyl radical NBT+ which is disproportional to yield a highly colored formazan dye (MF+) (monoformazen), absorbance of colored compound was measured which gives the concentration of glycated proteins present in the sample. Heme free globin (glycated hemoglobin) was extracted out and dissolved immediately in 1 ml normal saline. Dissolved globin was treated with modified NBT reagent, absorbance of color developed was recorded in milli delta A/min. The results of modified NBT were then compared with HbA1c estimated by immunoagglutination inhibition method. Correlation coefficient between Glycated hemoglobin and HbAlc was found to be r=0.926 using Schimadzu CL-750 spectrophotometer and r=0.902 using colorimeter. Results of this study were found to be statistically significant p NBT reduction method is as sensitive as HbAlc estimated by DCA2000+Analyzer (immunoagglutination inhibition). Hence it could be used for routine monitoring of blood glucose control level in diabetic subjects.

  20. Attenuation of Glucose-Induced Myoglobin Glycation and the Formation of Advanced Glycation End Products (AGEs by (R-α-Lipoic Acid In Vitro

    Directory of Open Access Journals (Sweden)

    Hardik Ghelani

    2018-02-01

    Full Text Available High-carbohydrate containing diets have become a precursor to glucose-mediated protein glycation which has been linked to an increase in diabetic and cardiovascular complications. The aim of the present study was to evaluate the protective effect of (R-α-lipoic acid (ALA against glucose-induced myoglobin glycation and the formation of advanced glycation end products (AGEs in vitro. Methods: The effect of ALA on myoglobin glycation was determined via the formation of AGEs fluorescence intensity, iron released from the heme moiety of myoglobin and the level of fructosamine. The extent of glycation-induced myoglobin oxidation was measured via the levels of protein carbonyl and thiol. Results: The results showed that the co-incubation of ALA (1, 2 and 4 mM with myoglobin (1 mg/mL and glucose (1 M significantly decreased the levels of fructosamine, which is directly associated with the decrease in the formation of AGEs. Furthermore, ALA significantly reduced the release of free iron from myoglobin which is attributed to the protection of myoglobin from glucose-induced glycation. The results also demonstrated a significant protective effect of ALA on myoglobin from oxidative damage, as seen from the decreased protein carbonyls and increased protein thiols. Conclusion: The anti-glycation properties of ALA suggest that ALA supplementation may be beneficial in the prevention of AGEs-mediated diabetic and cardiovascular complications.

  1. Glycation of Lysozyme by Glycolaldehyde Provides New Mechanistic Insights in Diabetes-Related Protein Aggregation.

    Science.gov (United States)

    Mariño, Laura; Maya-Aguirre, Carlos Andrés; Pauwels, Kris; Vilanova, Bartolomé; Ortega-Castro, Joaquin; Frau, Juan; Donoso, Josefa; Adrover, Miquel

    2017-04-21

    Glycation occurs in vivo as a result of the nonenzymatic reaction of carbohydrates (and/or their autoxidation products) with proteins, DNA, or lipids. Protein glycation causes loss-of-function and, consequently, the development of diabetic-related diseases. Glycation also boosts protein aggregation, which can be directly related with the higher prevalence of aggregating diseases in diabetic people. However, the molecular mechanism connecting glycation with aggregation still remains unclear. Previously we described mechanistically how glycation of hen egg-white lysozyme (HEWL) with ribose induced its aggregation. Here we address the question of whether the ribose-induced aggregation is a general process or it depends on the chemical nature of the glycating agent. Glycation of HEWL with glycolaldehyde occurs through two different scenarios depending on the HEWL concentration regime (both within the micromolar range). At low HEWL concentration, non-cross-linking fluorescent advanced glycation end-products (AGEs) are formed on Lys side chains, which do not change the protein structure but inhibit its enzymatic activity. These AGEs have little impact on HEWL surface hydrophobicity and, therefore, a negligible effect on its aggregation propensity. Upon increasing HEWL concentration, the glycation mechanism shifts toward the formation of intermolecular cross-links, which triggers a polymerization cascade involving the formation of insoluble spherical-like aggregates. These results notably differ with the aggregation-modulation mechanism of ribosylated HEWL directed by hydrophobic interactions. Additionally, their comparison constitutes the first experimental evidence showing that the mechanism underlying the aggregation of a glycated protein depends on the chemical nature of the glycating agent.

  2. Role of advanced glycation end products in cellular signaling

    Directory of Open Access Journals (Sweden)

    Christiane Ott

    2014-01-01

    Full Text Available Improvements in health care and lifestyle have led to an elevated lifespan and increased focus on age-associated diseases, such as neurodegeneration, cardiovascular disease, frailty and arteriosclerosis. In all these chronic diseases protein, lipid or nucleic acid modifications are involved, including cross-linked and non-degradable aggregates, such as advanced glycation end products (AGEs. Formation of endogenous or uptake of dietary AGEs can lead to further protein modifications and activation of several inflammatory signaling pathways. This review will give an overview of the most prominent AGE-mediated signaling cascades, AGE receptor interactions, prevention of AGE formation and the impact of AGEs during pathophysiological processes.

  3. Accumulation of advanced glycation end products in canine atherosclerosis.

    Science.gov (United States)

    Chiers, K; Vandenberge, V; Ducatelle, R

    2010-07-01

    Atherosclerosis is an uncommon lesion in animals and particularly in dogs. Prominent atherosclerotic lesions of the coronary arteries are described in three dogs. These comprised an expansion of the tunica media by the accumulation of foam cells and/or cholesterol crystals, with subsequent narrowing of the vascular lumen. Immunohistochemical analysis revealed the accumulation of advanced glycation end products (AGEs) in foam cells, macrophages and lymphocytes. As in man, these findings suggest a possible role of AGEs in the development of canine atherosclerosis. (c) 2009 Elsevier Ltd. All rights reserved.

  4. Effect of glycated insulin on the blood-brain barrier permeability: An in vitro study.

    Science.gov (United States)

    Shahriyary, Leila; Riazi, Gholamhossein; Lornejad, Mohammad Reza; Ghezlou, Mansoureh; Bigdeli, Bahareh; Delavari, Behdad; Mamashli, Fatemeh; Abbasi, Shayan; Davoodi, Jamshid; Saboury, Ali Akbar

    2018-02-11

    Alteration in permeability of blood-brain barrier (BBB) is of immense importance in the pathogenesis of diabetes-related central nervous system disorders. Considering the presence of glycated insulin in plasma of type 2 diabetic patients, we hypothesized that glycated insulin could induce changes in paracellular permeability in BBB. Therefore, the authors decided to study the effect of glycated insulin on paracellular permeability in a BBB model. Furthermore, the change induced in insulin conformation upon glycation was studied. In this study, the structural modification was detected by fluorescence-based assays, circular dichroism, and dynamic light scattering. Cell proliferation, apoptosis, and production of ROS in astrocytes and HUVEC cells were analyzed by MTT, flow cytometric, and spectrofluorometric assays, respectively. The permeability measurement was performed by Lucifer yellow and FITC-Dextran. According to our results, glycated insulin presented altered conformation and more exposed hydrophobic patches than insulin. Besides, formation of oligomeric species and advanced glycated end products (AGEs) were determined. Additionally, lower cell viability, higher apoptosis induction, and more ROS production were detected upon treatment of cells with glycated insulin. Furthermore, glycated insulin leading to increased Lucifer yellow and FITC-dextran transportation across the BBB model which could result from ROS producing and apoptosis-inducing activities of AGE-insulin. Copyright © 2018. Published by Elsevier Inc.

  5. Soluble receptor for advanced glycation end products (sRAGE) and ...

    African Journals Online (AJOL)

    Eman M. Sherif

    2014-07-10

    Jul 10, 2014 ... Abstract Background: Advanced glycation end products (AGEs) are a heterogeneous and com- plex group of biochemical compounds, resulting from nonenzymatic glycation and oxidation of protein, nucleic acids, and lipids. Aim of the study: To assess sRAGE and CIMT in patients with T1DM and their ...

  6. "STUDY ON THE EFFECT OF GARLIC ON THE IN VITRO ALBUMIN GLYCATION REACTION"

    Directory of Open Access Journals (Sweden)

    N. Sheikh

    2004-05-01

    Full Text Available Garlic, an antioxidant plant, can react with amino groups of proteins to form Schiff bases. As diabetes leads to glycation of various proteins and this in turn has some effects on the structure of proteins and biochemical activity of them, the inhibition of this process seems very vital. For several years researchers in this field have done their best to recognize the antidiabetic compounds. The aim of this study is to determine the effects of garlic on albumin glycation in vitro.In the presence of various concentrations of garlic, albumin was glycated and evaluated using TBA (thio-barbituric acid method. The results showed that garlic has a statistically significant (P<0.05 effect in inhibiting or decreasing the reaction of albumin glycation. The findings of this research shows that garlic probably inhibits the reaction of glycation and decreases complications occurring in diabetes.

  7. Glycation & the RAGE axis: targeting signal transduction through DIAPH1.

    Science.gov (United States)

    Shekhtman, Alexander; Ramasamy, Ravichandran; Schmidt, Ann Marie

    2017-02-01

    The consequences of chronic disease are vast and unremitting; hence, understanding the pathogenic mechanisms mediating such disorders holds promise to identify therapeutics and diminish the consequences. The ligands of the receptor for advanced glycation end products (RAGE) accumulate in chronic diseases, particularly those characterized by inflammation and metabolic dysfunction. Although first discovered and reported as a receptor for advanced glycation end products (AGEs), the expansion of the repertoire of RAGE ligands implicates the receptor in diverse milieus, such as autoimmunity, chronic inflammation, obesity, diabetes, and neurodegeneration. Areas covered: This review summarizes current knowledge regarding the ligand families of RAGE and data from human subjects and animal models on the role of the RAGE axis in chronic diseases. The recent discovery that the cytoplasmic domain of RAGE binds to the formin homology 1 (FH1) domain, DIAPH1, and that this interaction is essential for RAGE ligand-stimulated signal transduction, is discussed. Finally, we review therapeutic opportunities targeting the RAGE axis as a means to mitigate chronic diseases. Expert commentary: With the aging of the population and the epidemic of cardiometabolic disease, therapeutic strategies to target molecular pathways that contribute to the sequelae of these chronic diseases are urgently needed. In this review, we propose that the ligand/RAGE axis and its signaling nexus is a key factor in the pathogenesis of chronic disease and that therapeutic interruption of this pathway may improve quality and duration of life.

  8. Relationship between Advanced Glycation End Products and Steroidogenesis in PCOS.

    Science.gov (United States)

    Garg, Deepika; Merhi, Zaher

    2016-10-21

    Women with PCOS have elevated levels of the harmful Advanced Glycation End Products (AGEs), which are highly reactive molecules formed after glycation of lipids and proteins. Additionally, AGEs accumulate in the ovaries of women with PCOS potentially contributing to the well-documented abnormal steroidogenesis and folliculogenesis. A systematic review of articles and abstracts available in PubMed was conducted and presented in a systemic manner. This article reports changes in steroidogenic enzyme activity in granulosa and theca cells in PCOS and PCOS-models. It also described the changes in AGEs and their receptors in the ovaries of women with PCOS and presents the underlying mechanism(s) whereby AGEs could be responsible for the PCOS-related changes in granulosa and theca cell function thus adversely impacting steroidogenesis and follicular development. AGEs are associated with hyperandrogenism in PCOS possibly by altering the activity of various enzymes such as cholesterol side-chain cleavage enzyme cytochrome P450, steroidogenic acute regulatory protein, 17α-hydroxylase, and 3β-hydroxysteroid dehydrogenase. AGEs also affect luteinizing hormone receptor and anti-Mullerian hormone receptor expression as well as their signaling pathways in granulosa cells. A better understanding of how AGEs alter granulosa and theca cell function is likely to contribute meaningfully to a conceptual framework whereby new interventions to prevent and/or treat ovarian dysfunction in PCOS can ultimately be developed.

  9. A combined self-assembly and calcination method for preparation of nanoparticles-assembled cobalt oxide nanosheets using graphene oxide as template and their application for non-enzymatic glucose biosensing.

    Science.gov (United States)

    Zhang, Haiyan; Liu, Sen

    2017-01-01

    Cobalt oxide (Co 3 O 4 )-based materials have been extensively investigated as efficient electrocatalysts for non-enzymatic glucose biosensing. The proper tuning the structure of Co 3 O 4 -based materials could improve sensing performances for glucose detection. Herein, we have developed a combined self-assembly and calcination method to prepare nanoparticles-assembled Co 3 O 4 nanosheets, which exhibit good sensing performances for glucose biosensing. The Co 3 O 4 nanosheets were prepared by the following three steps: (i) the Co 2+ modified graphene oxide (GO) was prepared by the self-assembly of Co 2+ and GO in aqueous solution firstly, and then Co 2+ modified GO film was obtained by vacuum filtration method; (ii) after calcination of Co 2+ modified GO film in N 2 atmosphere, Co 3 O 4 nanoparticles modified reduced GO (RGO) was obtained; (iii) finally, nanoparticles-assembled Co 3 O 4 nanosheets were obtained by calcination of Co 3 O 4 modified RGO in air to remove RGO template. Most importantly, Co 3 O 4 nanosheets exhibit good electrocatalytic activity for oxidation of glucose, leading to high-performance glucose sensor. The detection limit and linear range of Co 3 O 4 nanosheets-based glucose sensor in the present work are 0.15μM, and 1-50μM, respectively. Furthermore, such sensor also shows excellent selectivity for glucose detection, compared to the commonly interfering species including dopamine, and uric acid. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ali Adem Bahar

    2013-11-01

    Full Text Available The rapid increase in drug-resistant infections has presented a serious challenge to antimicrobial therapies. The failure of the most potent antibiotics to kill “superbugs” emphasizes the urgent need to develop other control agents. Here we review the history and new development of antimicrobial peptides (AMPs, a growing class of natural and synthetic peptides with a wide spectrum of targets including viruses, bacteria, fungi, and parasites. We summarize the major types of AMPs, their modes of action, and the common mechanisms of AMP resistance. In addition, we discuss the principles for designing effective AMPs and the potential of using AMPs to control biofilms (multicellular structures of bacteria embedded in extracellular matrixes and persister cells (dormant phenotypic variants of bacterial cells that are highly tolerant to antibiotics.

  11. Sulforaphane inhibits advanced glycation end product-induced pericyte damage by reducing expression of receptor for advanced glycation end products.

    Science.gov (United States)

    Maeda, Sayaka; Matsui, Takanori; Ojima, Ayako; Takeuchi, Masayoshi; Yamagishi, Sho-Ichi

    2014-09-01

    Advanced glycation end products (AGEs) not only inhibit DNA synthesis but also play a role in diabetic retinopathy by evoking apoptosis and inflammation in retinal pericytes via interaction with a receptor for AGE (RAGE). Similarly, sulforaphane, which is a naturally occurring isothiocyanate that is found in widely consumed cruciferous vegetables, protects against oxidative stress-induced tissue damage. Therefore, we hypothesized that sulforaphane could inhibit AGE-induced pericytes injury through its antioxidative properties. Advanced glycation end product stimulated superoxide generation as well as RAGE gene and protein expression in bovine-cultured retinal pericytes, and these effects were prevented by the treatment with sulforaphane. Antibodies directed against RAGE also blocked AGE-evoked reactive oxygen species generation in pericytes. Sulforaphane and antibodies directed against RAGE significantly inhibited the AGE-induced decrease in DNA synthesis, apoptotic cell death, and up-regulation of monocyte chemoattractant protein 1 messenger RNA levels in pericytes. For the first time, the present study demonstrates that sulforaphane could inhibit DNA synthesis, apoptotic cell death, and inflammatory reactions in AGE-exposed pericytes, partly by suppressing RAGE expression via its antioxidative properties. Blockade of the AGE-RAGE axis in pericytes by sulforaphane might be a novel therapeutic target for the treatment of diabetic retinopathy. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Advanced glycation end product ligands for the receptor for advanced glycation end products: biochemical characterization and formation kinetics.

    Science.gov (United States)

    Valencia, Jessica V; Weldon, Stephen C; Quinn, Douglas; Kiers, Geesje H; DeGroot, Jeroen; TeKoppele, Johan M; Hughes, Thomas E

    2004-01-01

    Advanced glycation end products (AGEs) accumulate with age and at an accelerated rate in diabetes. AGEs bind cell-surface receptors including the receptor for advanced glycation end products (RAGE). The dependence of RAGE binding on specific biochemical characteristics of AGEs is currently unknown. Using standardized procedures and a variety of AGE measures, the present study aimed to characterize the AGEs that bind to RAGE and their formation kinetics in vitro. To produce AGEs with varying RAGE binding affinity, bovine serum albumin (BSA) AGEs were prepared with 0.5M glucose, fructose, or ribose at times of incubation from 0 to 12 weeks or for up to 3 days with glycolaldehyde or glyoxylic acid. The AGE-BSAs were characterized for RAGE binding affinity, fluorescence, absorbance, carbonyl content, reactive free amine content, molecular weight, pentosidine content, and N-epsilon-carboxymethyl lysine content. Ribose-AGEs bound RAGE with high affinity within 1 week of incubation in contrast to glucose- and fructose-AGE, which required 12 and 6 weeks, respectively, to generate equivalent RAGE ligands (IC50=0.66, 0.93, and 1.7 microM, respectively). Over time, all of the measured AGE characteristics increased. However, only free amine content robustly correlated with RAGE binding affinity. In addition, detailed protocols for the generation of AGEs that reproducibly bind RAGE with high affinity were developed, which will allow for further study of the RAGE-AGE interaction.

  13. IR spectroscopic investigation of the inhibition of the glycation process by acetylsalicylic acid

    Science.gov (United States)

    Otero de Joshi, Virginia; Gil, Herminia; Contreras, Silvia; Velasquez, William; Joshi, Narahari V.

    2000-05-01

    An IR spectroscopic study was carried out at room temperature for Human Serum albumin (HSA) glycated with fructose and glucose and inhibited with acetylsalicylic acid. The glycation process was carried out in our laboratory by a conventional method to confirm earlier reported observation of the effect of glycation on the intensity variation of the IR spectra, particularly, in the range 1500 cm-1 to 1700 cm-1 and around 3300 cm-1. IR spectra reveal that the effects of glycation of HSA by fructose are more intense than with glucose, which is the expected. Bovine serum albumin was also glycated using Glucose-6-phosphate disodium salt, and gamma-globulin was glycate with glucose, As expected, the glycation process was more intense with glucose-t-phosphate disodium salt. Acetyl salicylic acid was also used and its inhibitor effects could be observed in both cases, with glucose and with glucose-6-phosphate disodium salt even though, to a smaller extent with the latter. This is consistent with the earlier data and is explained on the basis of the attachment of macromolecules to (epsilon) -NH2 groups of lysines. The experimental results confirm that acetylsalicylic acid, indeed, acts as an inhibitor by acetylation of the (epsilon) -NG2 group where the sugars are supposed to be attached.

  14. Cross-linking in collagen by nonenzymatic glycation increases the matrix stiffness in rabbit achilles tendon.

    Science.gov (United States)

    Reddy, G Kesava

    2004-01-01

    Nonenzymatic glycation of connective tissue matrix proteins is a major contributor to the pathology of diabetes and aging. Previously the author and colleagues have shown that nonenzymatic glycation significantly enhances the matrix stability in the Achilles tendon (Reddy et al., 2002, Arch. Biochem. Biophys., 399, 174-180). The present study was designed to gain further insight into glycation-induced collagen cross-linking and its relationship to matrix stiffness in the rabbit Achilles tendon. The glycation process was initiated by incubating the Achilles tendons (n = 6) in phosphate-buffered saline containing ribose, whereas control tendons (n = 6) were incubated in phosphate-buffered saline without ribose. Eight weeks following glycation, the biomechanical attributes as well as the degree of collagen cross-linking were determined to examine the potential associations between matrix stiffness and molecular properties of collagen. Compared to nonglycated tendons, the glycated tendons showed increased maximum load, stress, strain, Young's modulus of elasticity, and toughness indicating that glycation increases the matrix stiffness in the tendons. Glycation of tendons resulted in a considerable decrease in soluble collagen content and a significant increase in insoluble collagen and pentosidine. Analysis of potential associations between the matrix stiffness and degree of collagen cross-linking showed that both insoluble collagen and pentosidine exhibited a significant positive correlation with the maximum load, stress, and strain, Young's modulus of elasticity, and toughness (r values ranging from.61 to.94) in the Achilles tendons. However, the soluble collagen content present in neutral salt buffer, acetate buffer, and acetate buffer containing pepsin showed an inverse relation with the various biomechanical attributes tested (r values ranging from.22 to.84) in the Achilles tendons. The results of the study demonstrate that glycation-induced collagen cross

  15. Protein and low molecular mass thiols as targets and inhibitors of glycation reactions.

    Science.gov (United States)

    Zeng, Jingmin; Davies, Michael J

    2006-12-01

    Protein glycation has been implicated in the aging process as well as the complications of diabetes (retinopathy, neuropathy, nephropathy, and atherosclerosis). The nitrogen substituents of Lys, Arg, and His residues and the N-terminus of proteins are known to be readily glycated. As the thiol group of Cys is a powerful nucleophile, we hypothesized that Cys residues should also be targets of glycation and that low molecular mass thiols may act as protective agents. In this study the role of thiol glycation, induced by dicarbonyls, in protein cross-link formation and damage prevention is examined. It is shown that incubation of creatine kinase with glyoxal results in protein cross-link formation, with this occurring concurrently with loss of thiol groups, enzyme inactivation, and formation of S-carboxymethylcysteine, a product of glyoxal adduction to Cys residues. Cross-links have also been detected between N-acetylcysteine and the Lys-rich protein histone H1, demonstrating the formation of thiol-glyoxal-amine cross-links. Mass spectrometry has been used to characterize some of these cross-links as 2-(alkylthio)acetamides. A range of low molecular mass thiols have been shown to inhibit dicarbonyl adduction to, and cross-linking of, the thiol-free protein lysozyme, consistent with these thiols being alternative (sacrificial) targets of glycation. Some of these thiols are more efficient modulators of glycation than established glycation inhibitors such as aminoguanidine. These data demonstrate that thiols are facile targets of glycation and that low molecular mass thiols are potent glycation inhibitors. These data may aid the design of therapeutic agents for the treatment of the complications of diabetes.

  16. Glycated Hemoglobin Measurement and Prediction of Cardiovascular Disease

    DEFF Research Database (Denmark)

    Di Angelantonio, Emanuele; Gao, Pei; Khan, Hassan

    2014-01-01

    of cardiovascular disease (CVD) risk. DESIGN, SETTING, AND PARTICIPANTS: Analysis of individual-participant data available from 73 prospective studies involving 294,998 participants without a known history of diabetes mellitus or CVD at the baseline assessment. MAIN OUTCOMES AND MEASURES: Measures of risk......,840 incident fatal and nonfatal CVD outcomes (13,237 coronary heart disease and 7603 stroke outcomes) were recorded. In analyses adjusted for several conventional cardiovascular risk factors, there was an approximately J-shaped association between HbA1c values and CVD risk. The association between HbA1c values......IMPORTANCE: The value of measuring levels of glycated hemoglobin (HbA1c) for the prediction of first cardiovascular events is uncertain. OBJECTIVE: To determine whether adding information on HbA1c values to conventional cardiovascular risk factors is associated with improvement in prediction...

  17. Activity of glycated chitosan and other adjuvants to PDT vaccines

    Science.gov (United States)

    Korbelik, Mladen; Banáth, Judit; Čiplys, Evaldas; Szulc, Zdzislaw; Bielawska, Alicja; Chen, Wei R.

    2015-03-01

    Glycated chitosan (GC), a water soluble galactose-conjugated natural polysaccharide, has proven to be an effective immunoadjuvant for treatment of tumors based on laser thermal therapy. It was also shown to act as adjuvant for tumor therapy with high-intensity ultrasound and in situ photodynamic therapy (PDT). In the present study, GC was examined as potential adjuvant to PDT-generated cancer vaccine. Two other agents, pure calreticulin protein and acid ceramidase inhibitor LCL521, were also tested as prospective adjuvants for use in conjunction with PDT vaccines. Single treatment with GC, included with PDT vaccine cells suspension, improved the therapeutic efficacy when compared to vaccine alone. This attractive prospect of GC application remains to be carefully optimized and mechanistically elucidated. Both calreticulin and LCL521 proved also effective adjuvants when combined with PDT vaccine tumor treatment.

  18. Aging ovary and the role for advanced glycation end products.

    Science.gov (United States)

    Pertynska-Marczewska, Magdalena; Diamanti-Kandarakis, Evanthia

    2017-03-01

    The hypothalamic gonadotropin-releasing hormone pulse generator, the pituitary gonadotropes, the ovaries, and the uterus play a crucial role in female fertility. A decline in reproductive performance represents a complex interplay of actions at all levels of the hypothalamic-pituitary-ovarian axis. Recently, in the field of female reproductive aging attention is drawn to the carbonyl stress theory. Advanced glycation end products (AGEs) contribute directly to protein damage, induce a chain of oxidative stress (OS) reactions, and increase inflammatory reactions. Here, we highlight some of the mechanisms underlying glycation damage in the ovary. Searches of electronic databases were performed. Articles relevant to possible role of OS, AGEs, and receptor for AGE (RAGE) in aging ovary were summarized in this interpretive literature review. Follicular microenvironment undergoes an increase in OS with aging. Data support the role of OS in ovulatory dysfunction because AGEs are well-recognized mediators of increased OS. RAGE and AGE-modified proteins with activated nuclear factor-kappa B are expressed in human ovarian tissue. It was suggested that accumulation of AGEs products at the level of the ovarian follicle might trigger early ovarian aging or could be responsible for reduced glucose uptake by granulosa cells, potentially altering follicular growth. Moreover, impaired methylglyoxal detoxification causing relevant damage to the ovarian proteome might be one of the mechanisms underlying reproductive aging. Further investigation of the role for the AGE-RAGE axis in the ovarian follicular environment is needed, and results could relate to assisted reproduction technology outcomes and new measures of ovarian reserve.

  19. Treatment of periodontal disease in diabetics reduces glycated hemoglobin.

    Science.gov (United States)

    Grossi, S G; Skrepcinski, F B; DeCaro, T; Robertson, D C; Ho, A W; Dunford, R G; Genco, R J

    1997-08-01

    Periodontal disease is a common infection-induced inflammatory disease among individuals suffering from diabetes mellitus. The purpose of this study was to assess the effects of treatment of periodontal disease on the level of metabolic control of diabetes. A total of 113 Native Americans (81 females and 32 males) suffering from periodontal disease and non-insulin dependent diabetes mellitus (NIDDM) were randomized into 5 treatment groups. Periodontal treatment included ultrasonic scaling and curettage combined with one of the following antimicrobial regimens: 1) topical water and systemic doxycycline, 100 mg for 2 weeks; 2) topical 0.12% chlorhexidine (CHX) and systemic doxycycline, 100 mg for 2 weeks; 3) topical povidone-iodine and systemic doxycycline, 100 mg for 2 weeks; 4) topical 0.12% CHX and placebo; and 5) topical water and placebo (control group). Assessments were performed prior to and at 3 and 6 months after treatment and included probing depth (PD), clinical attachment level (CAL), detection of Porphyromonas gingivalis in subgingival plaque and determination of serum glucose and glycated hemoglobin (HbA1c). After treatment all study groups showed clinical and microbial improvement. The doxycycline-treated groups showed the greatest reduction in probing depth and subgingival Porphyromonas gingivalis compared to the control group. In addition, all 3 groups receiving systemic doxycycline showed, at 3 months, significant reductions (P periodontal infection and reduction of periodontal inflammation is associated with a reduction in level of glycated hemoglobin. Control of periodontal infections should thus be an important part of the overall management of diabetes mellitus patients.

  20. Synthetic antifreeze peptide

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  1. The receptor for advanced glycation end products in ventilator-induced lung injury

    NARCIS (Netherlands)

    Kuipers, Maria T.; Aslami, Hamid; Tuinman, Pieter Roel; Tuip-de Boer, Anita M.; Jongsma, Geartsje; van der Sluijs, Koenraad F.; Choi, Goda; Wolthuis, Esther K.; Roelofs, Joris J. T. H.; Bresser, Paul; Schultz, Marcus J.; van der Poll, Tom; Wieland, Catharina W.

    2014-01-01

    Mechanical ventilation (MV) can cause ventilator-induced lung injury (VILI). The innate immune response mediates this iatrogenic inflammatory condition. The receptor for advanced glycation end products (RAGE) is a multiligand receptor that can amplify immune and inflammatory responses. We

  2. Receptor for advanced glycation end products is protective during murine tuberculosis

    NARCIS (Netherlands)

    van Zoelen, Marieke A. D.; Wieland, Catharina W.; van der Windt, Gerritje J. W.; Florquin, Sandrine; Nawroth, Peter P.; Bierhaus, Angelika; van der Poll, Tom

    2012-01-01

    The development of active tuberculosis after infection with Mycobacterium tuberculosis is almost invariably associated with a persistent or transient state of relative immunodeficiency. The receptor for advanced glycation end products (RAGE) is a promiscuous receptor that is involved in pulmonary

  3. Receptor for advanced glycation end products is protective during murine tuberculosis.

    NARCIS (Netherlands)

    Zoelen, M.A. van; Wieland, C.W.; Windt, G.J. van der; Florquin, S.; Nawroth, P.P.; Bierhaus, A.; Poll, T. van der

    2012-01-01

    The development of active tuberculosis after infection with Mycobacterium tuberculosis is almost invariably associated with a persistent or transient state of relative immunodeficiency. The receptor for advanced glycation end products (RAGE) is a promiscuous receptor that is involved in pulmonary

  4. The receptor for advanced glycation end products in ventilator-induced lung injury

    NARCIS (Netherlands)

    Kuipers, Maria T; Aslami, Hamid; Tuinman, Pieter Roel; Tuip-de Boer, Anita M; Jongsma, Geartsje; van der Sluijs, Koenraad F; Choi, Goda; Wolthuis, Esther K; Roelofs, Joris Jth; Bresser, Paul; Schultz, Marcus J; van der Poll, Tom; Wieland, Catharina W

    2014-01-01

    BACKGROUND: Mechanical ventilation (MV) can cause ventilator-induced lung injury (VILI). The innate immune response mediates this iatrogenic inflammatory condition. The receptor for advanced glycation end products (RAGE) is a multiligand receptor that can amplify immune and inflammatory responses.

  5. Pathophysiology and therapeutics of premature ageing in chronic kidney disease, with a focus on glycative stress.

    Science.gov (United States)

    Hirakawa, Yosuke; Jao, Tzu-Ming; Inagi, Reiko

    2017-12-01

    Chronic kidney disease (CKD) is a major concern in public health. The pathology of CKD includes premature ageing in the kidney and vessels, which results in a high risk of cardiovascular events and end-stage renal disease. Many factors are involved in premature ageing in CKD, including hormonal imbalance, glycative stress, nitrogenous metabolites, and oxidative stress. Of these, the most important role in premature ageing in CKD is played by glycative stress, namely a massive and unfavourable glycation state, since the kidney is responsible for the clearance of advanced glycation endproducts (AGEs). In an animal model, overexpression of glyoxalase I (GLO-1), a detoxifier of AGEs, has been found to alleviate premature ageing in the kidney and vessels. Both lifestyle changes and drug therapy have shown promise in overcoming premature ageing. Promising drug therapies include a GLO-1 activator and an absorbent against glycotoxin and nitrogenous metabolites. © 2017 John Wiley & Sons Australia, Ltd.

  6. Characterisation of advanced glycation endproducts in saliva from patients with diabetes mellitus

    International Nuclear Information System (INIS)

    Yoon, Min-Sung; Jankowski, Vera; Montag, Susanne; Zidek, Walter; Henning, Lars; Schlueter, Hartmut; Tepel, Martin; Jankowski, Joachim

    2004-01-01

    Patients with diabetes mellitus are prone to develop increased advanced glycation endproducts causing local complications and increased overall morbidity and mortality. Nuclear magnetic resonance spectra were determined in saliva of 52 consecutive patients with diabetes mellitus and 47 age-matched healthy control subjects. Resonance spectra showed specific peaks at 2.3, 7.3, and 8.4 ppm in saliva from patients with diabetes mellitus. These peaks could be generated by incubation of saliva from healthy control subjects with hypochloric acid in vitro, indicating the presence of advanced glycation endproducts. The presence of advanced glycation endproducts in patients with diabetes mellitus was associated with approximal plaque index, indicating increased periodontal damage. The study indicates that increased advanced glycation endproducts are involved in the pathogenesis of diabetic complications

  7. Preservative effects of Aspirin on Human Hemoglobin glycation in Diabetic Condition

    OpenAIRE

    A Divsalar; J Behroozi; AA Saboury; NN Poursasan

    2013-01-01

    Abstract Background & aim: Diabetes is a common disease which is characterized by hyperglycemia and the increase of protein glycation. The aim of this study was to investigate the effect of aspirin-induced damage in human hemoglobin in diabetic glycation. Materials & Methods: In this study, hemoglobin extracted from the blood of healthy individuals was incubated in the presence and absence of glucose and aspirin for 5 weeks. The rate of haem glycotation was determined in different cond...

  8. Survey of the Distribution of a Newly Characterized Receptor for Advanced Glycation End Products in Tissues

    OpenAIRE

    Brett, Jerold; Schmidt, Ann Marie; Yan, Shi Du; Zou, Yu Shan; Weidman, Elliott; Pinsky, David; Nowygrod, Roman; Neeper, Michael; Przysiecki, Craig; Shaw, Alan; Migheli, Antonio; Stern, David

    1993-01-01

    Advanced glycation end products (AGEs), the final products of nonenzymatic glycation and oxidation of proteins, are found in the plasma and accumulate in the tissues during aging and at an accelerated rate in diabetes. A novel integral membrane protein, termed receptor for AGE (RAGE), forms a central part of the cell surface binding site for AGEs. Using monospecific, polyclonal antibody raised to human recombinant and bovine RAGE, immunostaining of bovine tissues showed RAGE in the vasculatur...

  9. Monotopic modifications derived from in vitro glycation of albumin with ribose

    Czech Academy of Sciences Publication Activity Database

    Pataridis, Statis; Šťastná, Zdeňka; Sedláková, Pavla; Mikšík, Ivan

    2013-01-01

    Roč. 34, č. 12 (2013), s. 1757-1763 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA203/08/1428 Institutional support: RVO:67985823 Keywords : advanced glycation end product (AGE) * albumin * CE-MS * glycation * LC-MS/MS Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.161, year: 2013

  10. Glycated albumin as a marker of glycemia in diabetes and its vascular complications

    Directory of Open Access Journals (Sweden)

    Maria Warwas

    2015-05-01

    Full Text Available Effective glycemic control is very important to prevent the onset and the progression of chronic complications in diabetic patients. It is known that glycation of various proteins is increased in diabetic patients compared with non-diabetics. Among these glycated proteins, glycated hemoglobin (HbA1c is commonly used as a gold standard index of glycemic control in the clinical setting. However, it can be unreliable in conditions affecting the lifespan of erythrocytes (120 days as well as in the clinical state in which glycemic control alleviates or deteriorates in a short period. By overcoming the shortcomings of HbA1c, glycated albumin (GA has gained interest as a useful index for an intermediate glycation period (2 weeks and pathogenic protein.After giving a brief overview of the key role of HbA1c as a long-term glycemic marker, this review focuses on (a glycation of human albumin and its main properties, (b methods of GA determination, (c the recent clinical status of GA as a glycemic index in diabetic patients and its association with vascular complications. Finally, conditions with a possible inaccurate GA level are also mentioned.

  11. Fluorescence lifetime measurements of native and glycated human serum albumin and bovine serum albumin

    Science.gov (United States)

    Joshi, Narahari V.; Joshi, Virgina O. d.; Contreras, Silvia; Gil, Herminia; Medina, Honorio; Siemiarczuk, Aleksander

    1999-05-01

    Nonenzymatic glycation, also known as Maillard reaction, plays an important role in the secondary complications of the diabetic pathology and aging, therefore, human serum albumin (HSA) and bovine serum albumin (BSA) were glycated by a conventional method in our laboratory using glucose as the glycating agent. Fluorescence lifetime measurements were carried out with a laser strobe fluorometer equipped with a nitrogen/dye laser and a frequency doubler as a pulsed excitation source. The samples were excited at 295 nm and the emission spectra were recorded at 345 nm. The obtained decay curves were tried for double and triple exponential functions. It has been found that the shorter lifetime increases for glycated proteins as compared with that of the native ones. For example, in the case of glycated BSA the lifetime increased from 1.36 ns to 2.30 ns. Similarly, for HSA, the lifetime increases from 1.58 ns to 2.26 ns. Meanwhile, the longer lifetime changed very slightly for both proteins (from 6.52 ns to 6.72 ns). The increase in the lifetime can be associated with the environmental effect; originated from the attachment of glucose to some lysine residues. A good example is Trp 214 which is in the cage of Lys 225, Lys 212, Lys 233, Lys 205, Lys 500, Lys 199 and Lys 195. If fluorescence lifetime technique is calibrated and properly used it could be employed for assessing glycation of proteins.

  12. Human peptide transporters

    DEFF Research Database (Denmark)

    Nielsen, Carsten Uhd; Brodin, Birger; Jørgensen, Flemming Steen

    2002-01-01

    Peptide transporters are epithelial solute carriers. Their functional role has been characterised in the small intestine and proximal tubules, where they are involved in absorption of dietary peptides and peptide reabsorption, respectively. Currently, two peptide transporters, PepT1 and PepT2, wh...

  13. [SYNTHETIC PEPTIDE VACCINES].

    Science.gov (United States)

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  14. Glycation of human cortical and cancellous bone captures differences in the formation of Maillard reaction products between glucose and ribose.

    Directory of Open Access Journals (Sweden)

    Grażyna E Sroga

    Full Text Available To better understand some aspects of bone matrix glycation, we used an in vitro glycation approach. Within two weeks, our glycation procedures led to the formation of advanced glycation end products (AGEs at the levels that corresponded to approx. 25-30 years of the natural in vivo glycation. Cortical and cancellous bones from human tibias were glycated in vitro using either glucose (glucosylation or ribose (ribosylation. Both glucosylation and ribosylation led to the formation of higher levels of AGEs and pentosidine (PEN in cancellous than cortical bone dissected from all tested donors (young, middle-age and elderly men and women. More efficient glycation of bone matrix proteins in cancellous bone most likely depended on the higher porosity of this tissue, which facilitated better accessibility of the sugars to the matrix proteins. Notably, glycation of cortical bone from older donors led to much higher AGEs levels as compared to young donors. Such efficient in vitro glycation of older cortical bone could result from aging-related increase in porosity caused by the loss of mineral content. In addition, more pronounced glycation in vivo would be driven by elevated oxidation processes. Interestingly, the levels of PEN formation differed pronouncedly between glucosylation and ribosylation. Ribosylation generated very high levels of PEN (approx. 6- vs. 2.5-fold higher PEN level than in glucosylated samples. Kinetic studies of AGEs and PEN formation in human cortical and cancellous bone matrix confirmed higher accumulation of fluorescent crosslinks for ribosylation. Our results suggest that in vitro glycation of bone using glucose leads to the formation of lower levels of AGEs including PEN, whereas ribosylation appears to support a pathway toward PEN formation. Our studies may help to understand differences in the progression of bone pathologies related to protein glycation by different sugars, and raise awareness for excessive sugar

  15. Transcapillary escape rate and relative metabolic clearance of glycated and non-glycated albumin in type 1 (insulin-dependent) diabetes mellitus

    DEFF Research Database (Denmark)

    Bent-Hansen, L; Feldt-Rasmussen, B; Kverneland, A

    1987-01-01

    The transcapillary escape rate and relative plasma disappearance of glycated and non-glycated albumin were measured in 25 male Type 1 (insulin-dependent) diabetic patients using a double tracer technique. The patients were divided into three groups on the basis of their urinary albumin excretion......: group 1, normal albumin excretion (less than 30 mg/24 h) (n = 8); group 2, microalbuminuria (30-300 mg/24 h) (n = 9); and group 3, clinical nephropathy (greater than 300 mg/24 h) (n = 8). Six male age-matched non-diabetic persons served as control subjects. The transcapillary escape rate of glycated...... albumin was similar in group 1 and control subjects (4.7 +/- 2.1 versus 5.1 +/- 1.7%), but significantly increased in group 2 (7.0 +/- 1.7%, p less than 0.05) and in group 3 (7.9 +/- 3.1%, p less than 0.05). The transcapillary escape rate of glycated albumin was slightly lower than that of non...

  16. Comparative study of NBT reduction method for estimation of glycated protein (serum fructoseamine) with glycated HbA1c estimated on DCA 2000+Analyzer (immunoagglutination inhibition).

    Science.gov (United States)

    Sahu, Ashok; Sarkar, Purnima Dey

    2008-01-01

    Glycated protein estimation is a diagnostic tool, used for the long term and short term monitoring of the glycemic status of diabetic patients. The present study is designed to compare and correlate modified NBT reduction method for the estimation of Glycated protein (serum fructosamine) with HbAlc estimated on DCA+2000 Analyzer. Glycated protein (serum fructosamine) reduces Nitro Blue Tetrazolium (NBT) reagent in alkaline medium to tetrazinolyl radical NBT+ which forms a highly colored monoformazen compound, absorbance of which is directly proportional to the concentration of glycated protein (serum fructosamine) present in the sample and is recorded as delta A/min. The results of modified NBT were then compared with HbA1c estimated by immunoagglutination inhibition method. Correlation coefficient between HbAlc with serum fructosamine was found to be r = 0.739 using Schimadzu CL-750 spectrophotometer and r = 0.731 using colorimeter. Results of this study were found to be statistically significant P < 0.001. Hence this method could be used for routine monitoring of blood glucose control in diabetics as HbA1c estimation.

  17. Variations in native protein glycation and plasma antioxidants in several birds of prey.

    Science.gov (United States)

    Ingram, Tana; Zuck, Jessica; Borges, Chad R; Redig, Patrick; Sweazea, Karen L

    2017-08-01

    Birds are an anomaly among vertebrates as they are remarkably long-lived despite having naturally high blood glucose and metabolic rates. For mammals, hyperglycemia leads to oxidative stress and protein glycation. In contrast, many studies have shown that domestic and wild birds are relatively resistant to these glucose-mediated pathologies. Surprisingly very little research has examined protein glycation in birds of prey, which by nature consume a diet high in protein and fat that promotes gluconeogenesis. The purpose of this study was to evaluate protein glycation and antioxidant concentrations in serum samples from several birds of prey (bald eagle (BAEA), red-tailed hawk (RTHA), barred owl (BAOW), great horned owl (GHOW)) as protein glycation can accelerate oxidative stress and vice versa. Serum glucose was measured using a commercially available assay, native albumin glycation was measured by mass spectrometry and various antioxidants (uric acid, vitamin E, retinol and several carotenoids) were measured by high performance liquid chromatography. Although glucose concentrations were not significantly different between species (p=0.340), albumin glycation was significantly higher (p=0.004) in BAEA (23.67±1.90%) and BAOW (24.28±1.43%) compared to RTHA (14.31±0.63%). Of the antioxidants examined, lutein was significantly higher in BAOW (p=0.008). BAEA had the highest beta-cryptoxanthin and beta-carotene concentrations (pbirds of prey relative to other birds likely helps protect from complications that may otherwise arise from having high glucose and protein glycation. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Acute insulin resistance mediated by advanced glycation endproducts in severely burned rats.

    Science.gov (United States)

    Zhang, Xing; Xu, Jie; Cai, Xiaoqing; Ji, Lele; Li, Jia; Cao, Bing; Li, Jun; Hu, Dahai; Li, Yan; Wang, Haichang; Xiong, Lize; Xiao, Ruiping; Gao, Feng

    2014-06-01

    Hyperglycemia often occurs in severe burns; however, the underlying mechanisms and importance of managing postburn hyperglycemia are not well recognized. This study was designed to investigate the dynamic changes of postburn hyperglycemia and the underlying mechanisms and to evaluate whether early glycemic control is beneficial in severe burns. Prospective, randomized experimental study. Animal research laboratory. Sprague-Dawley rats. Anesthetized rats were subjected to a full-thickness burn injury comprising 40% of the total body surface area and were randomized to receive vehicle, insulin, and a soluble form of receptor for advanced glycation endproducts treatments. An in vitro study was performed on cultured H9C2 cells subjected to vehicle or carboxymethyllysine treatment. We found that blood glucose change presented a distinct pattern with two occurrences of hyperglycemia at 0.5- and 3-hour postburn, respectively. Acute insulin resistance evidenced by impaired insulin signaling and glucose uptake occurred at 3-hour postburn, which was associated with the second hyperglycemia and positively correlated with mortality. Mechanistically, we found that serum carboxymethyllysine, a dominant species of advanced glycation endproducts, increased within 1-hour postburn, preceding the occurrence of insulin resistance. More importantly, treatment of animals with soluble form of receptor for advanced glycation endproducts, blockade of advanced glycation endproducts signaling, alleviated severe burn-induced insulin resistance. In addition, early hyperglycemic control with insulin not only reduced serum carboxymethyllysine but also blunted postburn insulin resistance and reduced mortality. These findings suggest that severe burn-induced insulin resistance is partly at least mediated by serum advanced glycation endproducts and positively correlated with mortality. Early glycemic control with insulin or inhibition of advanced glycation endproducts with soluble form of receptor

  19. Effect of germanium-132 on galactose cataracts and glycation in rats.

    Science.gov (United States)

    Unakar, N J; Johnson, M; Tsui, J; Cherian, M; Abraham, E C

    1995-08-01

    Germanium compounds have been shown to be effective in preventing the formation of advanced glycation end-products and for reversible solubilization of glycated proteins. As protein glycation has been proposed to play a role in lens opacification, we initiated studies to evaluate the effects of 2-carboxyethyl germanium sesquioxide (germanium compound 132 or Ge-132) on galactose-induced cataractogenesis. For this study young Sprague-Dawley rats were fed a 50% galactose diet. One group of rats received topical saline and another group was administered Ge-132 in saline four times a day. The lenses were periodically examined with an ophthalmoscope and at desired intervals processed for light and scanning electron microscopy. Our observations, beginning at 3 days and continuing to 21 days of galactose feeding, exhibited the characteristic galactose-induced morphological alterations, which include the formation of vacuoles, cysts, membrane disruption and swelling of fibers and epithelial cells as well as disorganization of the bow in lenses of rats in both groups. However, in the majority of rats administered Ge-132 these alterations were delayed as compared to the lenses of rats administered saline. Our findings show that, although the initiation, progression and pattern of lens opacification in rats receiving saline and Ge-132 were similar, in the majority of lenses the progression and establishment of mature cataracts in the Ge-132 group of rats were delayed. Analysis of the water-soluble and water-insoluble lens-protein fractions for glycated proteins showed increased levels of the Amadori products and advanced glycation related fluorescent products in galactosemic rats treated with saline eye drops. In rats receiving the topical Ge-132 treatment the levels of these glycation products were substantially reduced to levels lower than control values. Prevention of glycation seems to be a mechanism by which cataract progression is delayed.

  20. Produtos da glicação avançada dietéticos e as complicações crônicas do diabetes Dietetics advanced glycation end-products and chronic complications of diabetes

    Directory of Open Access Journals (Sweden)

    Júnia Helena Porto Barbosa

    2009-02-01

    a conduta terapêutica, concorrendo para a melhoria da qualidade de vida dos portadores dessa enfermidade.The generation of advanced glycation end products is one of the principal mechanisms that lead to the pathologies associated with diabetes mellitus, which include cardiopathy, retinopathy, neuropathy and nephropathy. The objective of this revision is to analyse the role of the advanced glycation end products present in food as intermediaries of diabetic complications, presenting strategies to reduce their ingestion. For this purpose, research was carried out in databases of publications of the area, for the last 15 years, taking into account revision, experimental and clinical studies. Advanced glycation end products are a heterogenous group of molecules coming from non-enzymatic reactions between amino and carbonyl groups, examples being carboxymethyllisine and pentosidine found in food and in vivo. The advanced glycation end products ingested are absorbed and, along with endogenous advanced glycation end-products, promote the progression of the complications of diabetes. There is a direct correlation between advanced glycation end products consumption and blood concentration. Their restriction in food results in the suppression of serum levels of the markers of vascular disease and the intermediaries of inflammation directly involved in the development of diabetic degenerations. The current dietary orientations are concentrated on the proportion of nutrients and on energetic restriction. The risk of ingestion of advanced glycation end products formed during the processing of food should be taken in consideration. It is simply recommended that in the preparation of food, the use of low temperatures for short periods, in the presence of water, has important effects in the prevention of the complications of diabetes. The study of the mechanisms involved in the generation of advanced glycation end products and the antiglycation properties of compounds presented in

  1. Microglial cell death induced by glycated bovine serum albumin: nitric oxide involvement.

    Science.gov (United States)

    Khazaei, Mohammad R; Habibi-Rezaei, Mehran; Karimzadeh, Fereshteh; Moosavi-Movahedi, Ali Akbar; Sarrafnejhad, Abdo Alfattah; Sabouni, Farzaneh; Bakhti, Mostafa

    2008-08-01

    Nonenzymatic glycation results in the formation of advanced glycation end products (AGEs) through a nonenzymatic multistep reaction of reducing sugars with proteins. AGEs have been suspected to be involved in the pathogenesis of several chronic clinical neurodegenerative complications including Alzheimer's disease, which is characterized with the activation of microglial cells in neuritic plaques. To find out the consequence of this activation on microglial cells, we treated the cultured microglial cells with different glycation levels of Bovine Serum Albumin (BSA) which were prepared in vitro. Extent of glycation of protein has been characterized during 16 weeks of incubation with glucose. Treatment of microglial cells with various levels of glycated albumin induced nitric oxide (NO) production and consequently cell death. We also tried to find out the mode of death in AGE-activated microglial cells. Altogether, our results suggest that AGE treatment causes microglia to undergo NO-mediated apoptotic and necrotic cell death in short term and long term, respectively. NO production is a consequence of iNOS expression in a JNK dependent RAGE signalling after activation of RAGE by AGE-BSA.

  2. The Effect of Turmeric , Cardamom and Ginger on in vitro Albumin Glycation

    Directory of Open Access Journals (Sweden)

    N. Sheikh

    2004-01-01

    Full Text Available Diabetes mellitus is one of the most common disease in the world that imposes a tremendous health and societal burden whether that burden is measured in terms of sickness , use of health systems resources or costs. Hyperglycemia is the most important clinical sign of diabetes leading to glycation of the various proteins in the body that leads to change in their nature , structure and biochemical activity. One of the probable methods in the treatment of diabetes mellitus is decrease or inhibition of this reaction. It seems that Turmeric , Cardamom and Ginger are useful for this purpose. The main goal of this research is to determine the effect of above agents on in vitro albumin glycation. In the presence of various concentration of these agents , albumin was glycated and evaluated using TBA method. Results showed that these food additives have inhibitory effects on albumin glycation reaction with the concentraction of 1 g/dl , 0.2 g/dl and 0.1 g/dl. Among these agents , Ginger had the most inhibitory effect (78% with the concentration of 1 g/dl. The sequence of effect is : Ginger > Cardamom > Turmeric These findings showed that these agents decrease albumin glycation reaction.

  3. Association of subclinical inflammation, glycated hemoglobin and risk for obstructive sleep apnea syndrome

    Science.gov (United States)

    D’Aurea, Carolina Vicaria Rodrigues; Cerazi, Bruno Gion de Andrade; Laurinavicius, Antonio Gabriele; Janovsky, Carolina Castro Porto Silva; Conceição, Raquel Dilguerian de Oliveira; Santos, Raul D; Bittencourt, Márcio Sommer

    2017-01-01

    ABSTRACT Objective To investigate the inter-relation between high sensitivity C-reactive protein and glycated hemoglobin in prediction of risk of obstructive sleep apnea. Methods We included all individuals participating in a check-up program at the Preventive Medicine Center of Hospital Israelita Albert Einstein in 2014. The Berlin questionnaire for risk of obstructive sleep apnea was used, and the high sensitivity C-reactive protein and glycated hemoglobin levels were evaluated. Results The sample included 7,115 participants (age 43.4±9.6 years, 24.4% women). The Berlin questionnaire showed changes in 434 (6.1%) individuals. This finding was associated with high sensitivity C-reactive protein and glycated hemoglobin levels (p<0.001). However, only the association between the Berlin questionnaire result and glycated hemoglobin remained significant in the adjusted multivariate analysis, for the traditional risk factors and for an additional model, including high-density lipoprotein cholesterol and triglycerides. Conclusion The glycated hemoglobin, even below the threshold for diagnosis of diabetes, is independently associated with obstructive sleep apnea syndrome, even after adjustment for obesity and C-reactive protein. These findings suggest a possible pathophysiological link between changes in insulin resistance and obstructive sleep apnea syndrome, independently from obesity or low-grade inflammation. PMID:28767909

  4. Anti-glycated activity prediction of polysaccharides from two guava fruits using artificial neural networks.

    Science.gov (United States)

    Yan, Chunyan; Lee, Jinsheng; Kong, Fansheng; Zhang, Dezhi

    2013-10-15

    High-efficiency ultrasonic treatment was used to extract the polysaccharides of Psidium guajava (PPG) and Psidium littorale (PPL). The aims of this study were to compare polysaccharide activities from these two guavas, as well as to investigate the relationship between ultrasonic conditions and anti-glycated activity. A mathematical model of anti-glycated activity was constructed with the artificial neural network (ANN) toolbox of MATLAB software. Response surface plots showed the correlation between ultrasonic conditions and bioactivity. The optimal ultrasonic conditions of PPL for the highest anti-glycated activity were predicted to be 256 W, 60 °C, and 12 min, and the predicted activity was 42.2%. The predicted highest anti-glycated activity of PPG was 27.2% under its optimal predicted ultrasonic condition. The experimental result showed that PPG and PPL possessed anti-glycated and antioxidant activities, and those of PPL were greater. The experimental data also indicated that ANN had good prediction and optimization capability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. RAGE, Receptor of Advanced Glycation Endoproducts, Negatively Regulates Chondrocytes Differentiation

    Science.gov (United States)

    Kurosaka, Yuko; Nishimura, Haruka; Tanabe, Motoki; Takakura, Yuuki; Iwai, Keisuke; Waki, Takuya; Fujita, Takashi

    2014-01-01

    RAGE, receptor for advanced glycation endoproducts (AGE), has been characterized as an activator of osteoclastgenesis. However, whether RAGE directly regulates chondrocyte proliferation and differentiation is unclear. Here, we show that RAGE has an inhibitory role in chondrocyte differentiation. RAGE expression was observed in chondrocytes from the prehypertrophic to hypertrophic regions. In cultured cells, overexpression of RAGE or dominant-negative-RAGE (DN-RAGE) demonstrated that RAGE inhibited cartilaginous matrix production, while DN-RAGE promoted production. Additionally, RAGE regulated Ihh and Col10a1 negatively but upregulated PTHrP receptor. Ihh promoter analysis and real-time PCR analysis suggested that downregulation of Cdxs was the key for RAGE-induced inhibition of chondrocyte differentiation. Overexpression of the NF-κB inhibitor I-κB-SR inhibited RAGE-induced NF-κB activation, but did not influence inhibition of cartilaginous matrix production by RAGE. The inhibitory action of RAGE was restored by the Rho family GTPases inhibitor Toxin B. Furthermore, inhibitory action on Ihh, Col10a1 and Cdxs was reproduced by constitutively active forms, L63RhoA, L61Rac, and L61Cdc42, but not by I-κB-SR. Cdx1 induced Ihh and Col10a1 expressions and directly interacted with Ihh promoter. Retinoic acid (RA) partially rescued the inhibitory action of RAGE. These data combined suggests that RAGE negatively regulates chondrocyte differentiation at the prehypertrophic stage by modulating NF-κB-independent and Rho family GTPases-dependent mechanisms. PMID:25275461

  6. Effect of dietary advanced glycation end products on mouse liver.

    Directory of Open Access Journals (Sweden)

    Raza Patel

    Full Text Available UNLABELLED: The exact pathophysiology of non-alcoholic steatohepatitis (NASH is not known. Previous studies suggest that dietary advanced glycation end products (AGEs can cause oxidative stress in liver. We aim to study the effects of dietary AGEs on liver health and their possible role in the pathogenesis of NASH. METHODS: Two groups of mice were fed the same diet except the AGE content varied. One group was fed a high AGE diet and the second group was fed a regular AGE diet. Liver histology, alanine aminotransferase, aspartate aminotransferase, fasting glucose, fasting insulin, insulin resistance and glucose tolerance were assessed. RESULTS: Histology revealed that neutrophil infiltration occurred in the livers of the high AGE group at week 26; steatosis did not accompany liver inflammation. At week 39 livers from both groups exhibited macro- or micro-steatosis, yet no inflammation was detected. Higher insulin levels were detected in the regular AGE group at week 26 (P = 0.034, compared to the high AGE group. At week 39, the regular AGE group showed higher levels of alanine aminotransferase (P<0.01 and aspartate aminotransferase (P = 0.02 than those of the high AGE group. CONCLUSIONS: We demonstrate that a high AGE diet can cause liver inflammation in the absence of steatosis. Our results show that dietary AGEs could play a role in initiating liver inflammation contributing to the disease progression of NASH. Our observation that the inflammation caused by high AGE alone did not persist suggests interesting future directions to investigate how AGEs contribute to pro-oxidative and anti-oxidative pathways in the liver.

  7. Skin autofluorescence, a marker of advanced glycation end products and oxidative stress, is increased in recently preeclamptic women

    NARCIS (Netherlands)

    Blaauw, Judith; Smit, Andries J.; van Pampus, Maria G.; van Doormaal, Jasper J.; Aarnoudse, Jan G.; Rakhorst, Gerhard; Graaff, Reindert

    Objective: Advanced glycation end-products are considered to be markers of oxidative stress and to be involved in the atherosclerotic process. We investigated skin autofluorescence, which reflected advanced glycation end-product accumulation, in recently preeclamptic women and its relationship with

  8. Skin advanced glycation end products in HIV infection are increased and predictive of development of cardiovascular events

    NARCIS (Netherlands)

    Sprenger, Herman G.; Bierman, Wouter F.; Martes, Melanie I.; Graaff, Reindert; van der Werf, Tjip S.; Smit, Andries J.

    2017-01-01

    Objective: HIV-1 infection is associated with an increased cardiovascular disease (CVD) risk. Advanced glycation end products are formed as stable markers of glycaemic and oxidative stress. Skin autofluorescence (SAF) as marker of accumulated advanced glycation end products is increased and

  9. Effect of Maillard induced glycation on protein hydrolysis by lysine/arginine and non-lysine/arginine specific proteases

    NARCIS (Netherlands)

    Deng, Y.; Wierenga, P.A.; Schols, H.A.; Sforza, S.; Gruppen, H.

    2017-01-01

    Enzymatic protein hydrolysis is sensitive to modifications of protein structure, e.g. Maillard reaction. In early stages of the reaction glycation takes place, modifying the protein primary structure. In later stages protein aggregation occurs. The specific effect of glycation on protein

  10. Reference values for the Chinese population of skin autofluorescence as a marker of advanced glycation end products accumulated in tissue

    NARCIS (Netherlands)

    Yue, X.; Hu, H.; Koetsier, M.; Graaff, R.; Han, C.

    Aim Advanced glycation end products play an important role in the pathophysiology of several chronic and age-related diseases, especially diabetes mellitus. Skin autofluorescence is a non-invasive method for assessing levels of tissue advanced glycation end products. This study aims to establish the

  11. Antimicrobial properties of nisin after glycation with lactose, maltodextrin and dextran and the thyme oil emulsions prepared thereof.

    Science.gov (United States)

    Chen, Huaiqiong; Davidson, P Michael; Zhong, Qixin

    2014-11-17

    To clarify the reported conflicting antimicrobial activities of nisin after glycation, nisin was glycated with lactose, maltodextrin, and dextran at 70 °C and 50% relative humidity for 1-24 h. Nisin before and after glycation was studied for the first time to prepare thyme oil emulsions. The activity of glycated nisin and the thyme oil emulsions was tested in both tryptic soy broth (TSB) and 2% reduced fat milk. Results showed that nisin glycated with a smaller saccharide for a longer duration had a higher degree of glycation and the reduced number of positive charges lowered its antibacterial activity. The emulsified thyme oil had an additive effect with either glycated or native nisin against Listeria monocytogenes Scott A and Bacillus subtilis in TSB and 2% reduced fat milk. However, emulsions were less effective against L. monocytogenes Scott A in milk than same units of native nisin and same concentration of free thyme oil, likely due to the reduced availability of thymol and carvacrol, the main components of thyme oil. These results showed that glycation of nisin cannot broaden its antimicrobial activity and nisin is not a good compound to prepare emulsions of essential oils. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Cross-Linking Behavior and Foaming Properties of Bovine a-Lactalbumin after Glycation with Various Saccharides

    NARCIS (Netherlands)

    Haar, ter R.; Westphal, Y.; Wierenga, P.A.; Schols, H.A.; Gruppen, H.

    2011-01-01

    a-Lactalbumin was glycated via the Maillard reaction in the dry state using various mono- and oligosaccharides. The reaction resulted not only in coupling of the saccharides to a-lactalbumin but also in cross-linked proteins. The glycation rate and the extent of cross-link formation were highly

  13. PeptideAtlas

    Data.gov (United States)

    U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

  14. The role of advanced glycation end products in various types of neurodegenerative disease: a therapeutic approach.

    Science.gov (United States)

    Salahuddin, Parveen; Rabbani, Gulam; Khan, Rizwan Hasan

    2014-09-01

    Protein glycation is initiated by a nucleophilic addition reaction between the free amino group from a protein, lipid or nucleic acid and the carbonyl group of a reducing sugar. This reaction forms a reversible Schiff base, which rearranges over a period of days to produce ketoamine or Amadori products. The Amadori products undergo dehydration and rearrangements and develop a cross-link between adjacent proteins, giving rise to protein aggregation or advanced glycation end products (AGEs). A number of studies have shown that glycation induces the formation of the β-sheet structure in β-amyloid protein, α-synuclein, transthyretin (TTR), copper-zinc superoxide dismutase 1 (Cu, Zn-SOD-1), and prion protein. Aggregation of the β-sheet structure in each case creates fibrillar structures, respectively causing Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, familial amyloid polyneuropathy, and prion disease. It has been suggested that oligomeric species of glycated α-synuclein and prion are more toxic than fibrils. This review focuses on the pathway of AGE formation, the synthesis of different types of AGE, and the molecular mechanisms by which glycation causes various types of neurodegenerative disease. It discusses several new therapeutic approaches that have been applied to treat these devastating disorders, including the use of various synthetic and naturally occurring inhibitors. Modulation of the AGE-RAGE axis is now considered promising in the prevention of neurodegenerative diseases. Additionally, the review covers several defense enzymes and proteins in the human body that are important anti-glycating systems acting to prevent the development of neurodegenerative diseases.

  15. Inhibitory effect of gold nanoparticles on the D-ribose glycation of bovine serum albumin

    Directory of Open Access Journals (Sweden)

    Liu W

    2014-11-01

    Full Text Available Weixi Liu,1 Menashi A Cohenford,1–3 Leslie Frost,3 Champika Seneviratne,4 Joel A Dain1 1Department of Chemistry, University of Rhode Island, Kingston, RI, USA; 2Department of Integrated Science and Technology, 3Department of Chemistry, Marshall University, Huntington, WV, USA; 4Department of Chemistry, College of the North Atlantic, Labrador, NL, Canada Abstract: Formation of advanced glycation end products (AGEs by nonenzymatic glycation of proteins is a major contributory factor to the pathophysiology of diabetic conditions including senile dementia and atherosclerosis. This study describes the inhibitory effect of gold nanoparticles (GNPs on the D-ribose glycation of bovine serum albumin (BSA. A combination of analytical methods including ultraviolet–visible spectrometry, high performance liquid chromatography, circular dichroism, and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry were used to determine the extent of BSA glycation in the presence of citrate reduced spherical GNPs of various sizes and concentrations. GNPs of particle diameters ranging from 2 nm to 20 nm inhibited BSA’s AGE formation. The extent of inhibition correlated with the total surface area of the nanoparticles. GNPs of highest total surface area yielded the most inhibition whereas those with the lowest total surface area inhibited the formation of AGEs the least. Additionally, when GNPs’ total surface areas were set the same, their antiglycation activities were similar. This inhibitory effect of GNPs on BSA’s glycation by D-ribose suggests that colloidal particles may have a therapeutic application for the treatment of diabetes and conditions that promote hyperglycemia. Keywords: gold nanoparticles, glycation, AGEs, GNPs, BSA

  16. Characteristics of glycation and glycation sites of lysozyme by matrix-assisted laser desorption/ionization time of flight/time-of-flight mass spectrometry and Liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Ruan, Eric Dongliang; Wang, Hui; Ruan, Yuanyuan; Juáreza, Manuel

    2014-01-01

    Protein glycation with reducing sugars through the Maillard reaction is regarded as one of the most important reactions in food chem- istry. Amadori rearrangement products [ARPs] are produced at the initial stage of the Maillard reaction and then advanced glycation products may be formed. We report here that using matrix-assisted laser desorption/ionization mass spectrometry with time-of-flight detection [MALDI-TOF-MS] and electrospray ionization mass spectrometry (ESI-MSJ to monitor the glycation process in lysozyme and the D-glucose model system. MALDI-TOF-MS displayed a heterogeneous distribution of glycation via a total mass shift in spectra. However electrospray ionization mass spectrometry [ESI-MS] data showed that a total of four molecules of glucose reacted with Lysozyme at an increase in molecular weight by a 162 Da unit. Further, we identified the glycation sites of lysozyme by using MALDI-TOF/TOF-MS and Liquid chromatography [LC]-ESI-MS/MS. Besides the two glycation sites of Lys1 and Lys97 identified by MALDI-TOF/TOF-MS, the other two glycation sites of Lys13 and Lys116 were characterized unambiguously by LC-ESI-MS/MS. Both MALDI-TOF/TOF-MS and LC-ESI-MS/ MS provided confidence in the study of the glycation by restricting the number of possible residues through (un]modified ions. The study is useful to monitor and characterize glycation in protein systems based on both MALDI-TOF-MS and ESI-MS. Comparatively, LC-ESI-MS/MS provides more fragments with better recovery for the identification of glycation than MALDI-TOF/TOF-MS.

  17. Boronate-Modified Interdigitated Electrode Array for Selective Impedance-Based Sensing of Glycated Hemoglobin

    DEFF Research Database (Denmark)

    Boonyasit, Yuwadee; Laiwattanapaisal, Wanida; Chailapakul, Orawon

    2016-01-01

    An impedance-based label-free affinity sensor was developed for the recognition of glycated hemoglobin (HbA1c). Interdigitated gold microelectrode arrays (IDA) were first modified with a self-assembled monolayer of cysteamine followed by cross-linking with glutaraldehyde and subsequent binding of 3......-aminophenylboronic acid (APBA), which selectively binds HbA1c via cis-diol interactions. Impedance sensing was demonstrated to be highly responsive to the clinically relevant HbA1c levels (0.1%-8.36%) with a detection limit of 0.024% (3σ). The specificity of the assay was evaluated with non-glycated hemoglobin (Hb...

  18. Accumulation of glycation products in. cap alpha. -H pig lens crystallin and its bearing to diabetic cataract genesis

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, P.; Cabezas-Cerrato, J.

    1988-01-01

    The incorporation of /sup 11/C-glucose in native pig crystalline by in vitro incubation was found, after subsequent dialysis, to affect all 5 classes of crystallin separated by Sepharose CL-6B column chromatography. Though the radioactivity of the ..cap alpha..-H fraction was three times greater than that of any of the others, autoradiographs of SDS-PAGE gels showed /sup 11/C-glucose adducts to be present in all soluble protein subunits, without there being any evidence of preferential glycation of the ..cap alpha..-H subunits. The concentration of stable glycation products in the ..cap alpha..-H chromatographic fraction of soluble crystallins is suggested to be due the addition of glycated material to this fraction as result of glycation-induced hyperaggregation, and not because the ..cap alpha..-H subunits were especially susceptible to glycation.

  19. Advanced glycation endproducts in horses with insulin-induced laminitis.

    Science.gov (United States)

    de Laat, M A; Kyaw-Tanner, M T; Sillence, M N; McGowan, C M; Pollitt, C C

    2012-01-15

    Advanced glycation endproducts (AGEs) have been implicated in the pathogenesis of cancer, inflammatory conditions and diabetic complications. An interaction of AGEs with their receptor (RAGE) results in increased release of pro-inflammatory cytokines and reactive oxygen species (ROS), causing damage to susceptible tissues. Laminitis, a debilitating foot condition of horses, occurs in association with endocrine dysfunction and the potential involvement of AGE and RAGE in the pathogenesis of the disease has not been previously investigated. Glucose transport in lamellar tissue is thought to be largely insulin-independent (GLUT-1), which may make the lamellae susceptible to protein glycosylation and oxidative stress during periods of increased glucose metabolism. Archived lamellar tissue from horses with insulin-induced laminitis (n=4), normal control horses (n=4) and horses in the developmental stages (6h, 12h and 24h) of the disease (n=12) was assessed for AGE accumulation and the presence of oxidative protein damage and cellular lipid peroxidation. The equine-specific RAGE gene was identified in lamellar tissue, sequenced and is now available on GenBank. Lamellar glucose transporter (GLUT-1 and GLUT-4) gene expression was assessed quantitatively with qRT-PCR in laminitic and control horses and horses in the mid-developmental time-point (24 h) of the disease. Significant AGE accumulation had occurred by the onset of insulin-induced laminitis (48 h) but not at earlier time-points, or in control horses. Evidence of oxidative stress was not found in any group. The equine-specific RAGE gene was not expressed differently in treated and control animals, nor was the insulin-dependent glucose transporter GLUT-4. However, the glucose transporter GLUT-1 was increased in lamellar tissue in the developmental stages of insulin-induced laminitis compared to control horses and the insulin-independent nature of the lamellae may facilitate AGE formation. However, due to the lack of

  20. Advanced glycation end products and their relevance in female reproduction.

    Science.gov (United States)

    Merhi, Z

    2014-01-01

    Do advanced glycation end products (AGEs) and their receptors play a role in female reproduction? AGEs might contribute to the etiology of polycystic ovary syndrome (PCOS) and infertility. The endogenous AGEs are produced in the body by chemical reactions. Exogenous sources of AGEs are diet and smoking. AGEs have been proposed to be among the main intermediaries involved in several diseases, such as metabolic syndrome, type 2 diabetes mellitus, cardiovascular disease, ovarian aging, inflammation, neurodegenerative disorders and PCOS. A systematic review was performed for all available basic science and clinical peer-reviewed articles published in PubMed from 1987 to date. Abstracts of annual meetings of the Endocrine Society and American Society for Reproductive Medicine were also reviewed. A total of 275 publications and scientific abstracts were identified from the initial search. Sixty-two papers and four published scientific abstracts were selected for full review. The main outcomes were the regulatory effects of AGEs on: (i) granulosa cells, adipocyte physiology, obesity and insulin resistance in women with PCOS and in polycystic ovary animal models and (ii) infertility and measures of ovarian reserve. There is an intricate relationship between the AGE-RAGE (receptor for AGEs) system and some aspects of PCOS, such as granulosa cell dysfunction, adipocyte pathophysiology, obesity and insulin resistance. Additionally, irregular ovarian AGE signaling might in part explain the abnormal ovarian histology observed in women with PCOS. The ovarian dysfunction due to AGEs in women without PCOS suggests a role for the AGE-RAGE system in the ovarian follicular environment, and might relate to assisted reproduction technology outcome and measures of ovarian reserve. The body of literature currently available limits these findings. The results obtained from granulosa cell lines and animal models may not fully extrapolate to humans. This review underscores a critical need

  1. Glycated Hemoglobin Measurement and Prediction of Cardiovascular Disease

    Science.gov (United States)

    Angelantonio, Emanuele Di; Gao, Pei; Khan, Hassan; Butterworth, Adam S.; Wormser, David; Kaptoge, Stephen; Kondapally Seshasai, Sreenivasa Rao; Thompson, Alex; Sarwar, Nadeem; Willeit, Peter; Ridker, Paul M; Barr, Elizabeth L.M.; Khaw, Kay-Tee; Psaty, Bruce M.; Brenner, Hermann; Balkau, Beverley; Dekker, Jacqueline M.; Lawlor, Debbie A.; Daimon, Makoto; Willeit, Johann; Njølstad, Inger; Nissinen, Aulikki; Brunner, Eric J.; Kuller, Lewis H.; Price, Jackie F.; Sundström, Johan; Knuiman, Matthew W.; Feskens, Edith J. M.; Verschuren, W. M. M.; Wald, Nicholas; Bakker, Stephan J. L.; Whincup, Peter H.; Ford, Ian; Goldbourt, Uri; Gómez-de-la-Cámara, Agustín; Gallacher, John; Simons, Leon A.; Rosengren, Annika; Sutherland, Susan E.; Björkelund, Cecilia; Blazer, Dan G.; Wassertheil-Smoller, Sylvia; Onat, Altan; Marín Ibañez, Alejandro; Casiglia, Edoardo; Jukema, J. Wouter; Simpson, Lara M.; Giampaoli, Simona; Nordestgaard, Børge G.; Selmer, Randi; Wennberg, Patrik; Kauhanen, Jussi; Salonen, Jukka T.; Dankner, Rachel; Barrett-Connor, Elizabeth; Kavousi, Maryam; Gudnason, Vilmundur; Evans, Denis; Wallace, Robert B.; Cushman, Mary; D’Agostino, Ralph B.; Umans, Jason G.; Kiyohara, Yutaka; Nakagawa, Hidaeki; Sato, Shinichi; Gillum, Richard F.; Folsom, Aaron R.; van der Schouw, Yvonne T.; Moons, Karel G.; Griffin, Simon J.; Sattar, Naveed; Wareham, Nicholas J.; Selvin, Elizabeth; Thompson, Simon G.; Danesh, John

    2015-01-01

    IMPORTANCE The value of measuring levels of glycated hemoglobin (HbA1c) for the prediction of first cardiovascular events is uncertain. OBJECTIVE To determine whether adding information on HbA1c values to conventional cardiovascular risk factors is associated with improvement in prediction of cardiovascular disease (CVD) risk. DESIGN, SETTING, AND PARTICIPANTS Analysis of individual-participant data available from 73 prospective studies involving 294 998 participants without a known history of diabetes mellitus or CVD at the baseline assessment. MAIN OUTCOMES AND MEASURES Measures of risk discrimination for CVD outcomes (eg, C-index) and reclassification (eg, net reclassification improvement) of participants across predicted 10-year risk categories of low (<5%), intermediate (5%to <7.5%), and high (≥7.5%) risk. RESULTS During a median follow-up of 9.9 (interquartile range, 7.6-13.2) years, 20 840 incident fatal and nonfatal CVD outcomes (13 237 coronary heart disease and 7603 stroke outcomes) were recorded. In analyses adjusted for several conventional cardiovascular risk factors, there was an approximately J-shaped association between HbA1c values and CVD risk. The association between HbA1c values and CVD risk changed only slightly after adjustment for total cholesterol and triglyceride concentrations or estimated glomerular filtration rate, but this association attenuated somewhat after adjustment for concentrations of high-density lipoprotein cholesterol and C-reactive protein. The C-index for a CVD risk prediction model containing conventional cardiovascular risk factors alone was 0.7434 (95% CI, 0.7350 to 0.7517). The addition of information on HbA1c was associated with a C-index change of 0.0018 (0.0003 to 0.0033) and a net reclassification improvement of 0.42 (−0.63 to 1.48) for the categories of predicted 10-year CVD risk. The improvement provided by HbA1c assessment in prediction of CVD risk was equal to or better than estimated improvements for

  2. Designer Natriuretic Peptides

    Science.gov (United States)

    Lee, Candace Y. W.; Lieu, Hsiao; Burnett, John C.

    2011-01-01

    Designer natriuretic peptides (NPs) are novel hybrid peptides that are engineered from the native NPs through addition, deletion, or substitution of amino acid(s) with a goal toward optimization of pharmacological actions while minimizing undesirable effects. In this article, selected peptides that were designed in our laboratory are reviewed, and future directions for research and development of designer NPs are discussed. PMID:19158603

  3. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  4. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  5. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  6. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  7. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  8. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  9. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  10. Acylation of Therapeutic Peptides

    DEFF Research Database (Denmark)

    Trier, Sofie; Henriksen, Jonas Rosager; Jensen, Simon Bjerregaard

    to the harsh and selective gastrointestinal system, and development has lacked far behind injection therapy. Peptide acylation is a powerful tool to alter the pharmacokinetics, biophysical properties and chemical stability of injectable peptide drugs, primarily used to prolong blood circulation....... This work aims to characterize acylated analogues of two therapeutic peptides by systematically increasing acyl chain length in order to elucidate its influence on membrane interaction and intestinal cell translocation in vitro. The studied peptides are the 33 amino acid Glucagon-like peptide-2 (GLP-2...... peptides can increase in vitro intestinal permeability, modestly for GLP-2 and drastically for sCT, and might benefit oral delivery. GLP-2 results provide a well-founded predictive power for future peptide analogues, whereas sCT results hold great promise for future analogues, albeit with a larger...

  11. Genetic determinants of glycated hemoglobin levels in the Greenlandic Inuit population

    DEFF Research Database (Denmark)

    Appel, Emil V R; Moltke, Ida; Jørgensen, Marit E

    2018-01-01

    We previously showed that a common genetic variant leads to a remarkably increased risk of type 2 diabetes (T2D) in the small and historically isolated Greenlandic population. Motivated by this, we aimed at discovering novel genetic determinants for glycated hemoglobin (HbA1C) and at estimating...

  12. The Contribution of Advanced Glycation End product (AGE) accumulation to the decline in motor function

    NARCIS (Netherlands)

    Drenth, Hans; Zuidema, Sytse; Bunt, Steven; Bautmans, Ivan; van der Schans, Cees; Hobbelen, Hans

    2016-01-01

    Diminishing motor function is commonly observed in the elderly population and is associated with a wide range of adverse health consequences. Advanced Glycation End products (AGE's) may contribute to age-related decline in the function of cells and tissues in normal ageing. Although the negative

  13. Receptor for advanced glycation end product expression in experimental diabetic retinopathy

    NARCIS (Netherlands)

    Wang, Yumei; Hagen, Filanziska Vom; Pfister, Frederick; Bierhaus, Angelika; Feng, Yuxi; Gans, Reinhold; Hammes, Hans-Peter; Schleicher, E; Somoza,; Shieberle, P

    2008-01-01

    The advanced glycation end product (AGE)-receptor for AGE (RAGE) pathway is involved in the pathogenesis of diabetic microvascular damage. The special distribution of RAGE and its engagement has an impact on the development of diabetic retinopathy. In the present study, we used immunofluorescence

  14. Effect of collagen turnover on the accumulation of advanced glycation end products

    NARCIS (Netherlands)

    Verzijl, N.; Degroot, J.; Thorpe, S. R.; Bank, R. A.; Shaw, J. N.; Lyons, T. J.; Bijlsma, J. W.; Lafeber, F. P.; Baynes, J. W.; TeKoppele, J. M.

    2000-01-01

    Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE

  15. Role of protein-bound carbonyl groups in the formation of advanced glycation endproducts.

    Science.gov (United States)

    Liggins, J; Furth, A J

    1997-08-22

    Several mechanisms have been postulated for the formation of advanced glycation endproducts (AGEs) from glycated proteins; they all feature protein-bound carbonyl intermediates. Using 2,4-dinitrophenylhydrazine (DNPH), we have detected these intermediates on bovine serum albumin, lysozyme and beta-lactoglobulin after in vitro glycation by glucose or fructose. Carbonyls were formed in parallel with AGE-fluorophores, via oxidative Maillard reactions. Neither Amadori nor Heyns products contributed to the DNPH reaction. Fluorophore and carbonyl yields were much enhanced in lipid-associated proteins, but both groups could also be detected in lipid-free proteins. When pre-glycated proteins were incubated in the absence of free sugar, carbonyl groups were rapidly lost in a first-order reaction, while fluorescence continued to develop beyond the 21 days of incubation. Another unexpected finding was that not all carbonyl groups were blocked by aminoguanidine, although there was complete inhibition of reactions leading to AGE-fluorescence. It is suggested that carbonyls acting as fluorophore precursors react readily with aminoguanidine, while others are resistant to this hydrazine, possibly because they are involved in ring closure. Factors influencing the relative rates of acyclisation and hydrazone formation are discussed, together with possible implications for antiglycation therapy.

  16. The clinical relevance of assessing advanced glycation endproducts accumulation in diabetes

    NARCIS (Netherlands)

    Meerwaldt, Robbert; Links, Thera; Zeebregts, Clark; Tio, Rene; Hillebrands, Jan-Luuk; Smit, Andries

    2008-01-01

    Cardiovascular disease is the major cause of morbidity and mortality associated with diabetes. There is increasing evidence that advanced glycation endproducts (AGEs) play a pivotal role in atherosclerosis, in particular in diabetes. AGE accumulation is a measure of cumulative metabolic and

  17. Clinical and prognostic value of advanced glycation end-products in chronic heart failure

    NARCIS (Netherlands)

    Hartog, Jasper W. L.; Voors, Adriaan A.; Schalkwijk, Casper G.; Scheijen, Jean; Smilde, Tom D. J.; Damman, Kevin; Bakker, Stephan J. L.; Smit, Andries J.; van Veldhuisen, Dirk J.

    2007-01-01

    Aims Advanced glycation end-products (AGEs) have been proposed as a novel factor involved in the development and progression of chronic heart failure (CHF). We aimed to determine whether plasma levels of N-epsilon-(carboxymethyl)lysine (CML) and N-epsilon-(carboxyethyl)lysine (CEL), two well-known

  18. Advanced glycation end-products, a pathophysiological pathway in the cardiorenal syndrome

    NARCIS (Netherlands)

    Willemsen, Suzan; Hartog, Jasper W. L.; Heiner-Fokkema, Rebecca; van Veldhuisen, Dirk J.; Voors, Adriaan A.

    The prevalence of heart failure (HF) is increasing. A distinction is made between diastolic HF (preserved left ventricular ejection fraction (LVEF)) and systolic HF (reduced LVEF). Advanced glycation end-products (AGEs) are crystallized proteins that accumulate during ageing, but are particularly

  19. Receptor for Advanced Glycation End Products (RAGE) Serves a Protective Role during Klebsiella pneumoniae - Induced Pneumonia

    NARCIS (Netherlands)

    Achouiti, Ahmed; de Vos, Alex F.; van 't Veer, Cornelis; Florquin, Sandrine; Tanck, Michael W.; Nawroth, Peter P.; Bierhaus, Angelika; van der Poll, Tom; van Zoelen, Marieke A. D.

    2016-01-01

    Klebsiella species is the second most commonly isolated gram-negative organism in sepsis and a frequent causative pathogen in pneumonia. The receptor for advanced glycation end products (RAGE) is expressed on different cell types and plays a key role in diverse inflammatory responses. We here aimed

  20. A comparison of dicarbonyl stress and advanced glycation endproducts in lifelong endurance athletes vs. sedentary controls.

    NARCIS (Netherlands)

    Maessen, M.F.H.; Schalkwijk, C.G.; Verheggen, R.J.H.M.; Aengevaeren, V.L.; Hopman, M.T.E.; Eijsvogels, T.M.H.

    2017-01-01

    OBJECTIVES: Dicarbonyl stress and high concentrations of advanced glycation endproducts (AGEs) relate to an elevated risk for cardiovascular diseases (CVD). Exercise training lowers the risk for future CVD. We tested the hypothesis that lifelong endurance athletes have lower dicarbonyl stress and

  1. Total soluble and endogenous secretory receptor for advanced glycation endproducts (RAGE) in IBD

    NARCIS (Netherlands)

    Meijer, Berrie; Hoskin, Teagan; Ashcroft, Anna; Burgess, Laura; Keenan, Jacqueline I.; Falvey, James; Gearry, Richard B.; Day, Andrew S.

    2014-01-01

    Recruitment and activation of neutrophils, with release of specific proteins such as S100 proteins, is a feature of inflammatory bowel disease (IBD). Soluble forms of the receptor for advanced glycation endproducts (sRAGE), and variants such as endogenous secretory (esRAGE), can act as decoy

  2. Skin accumulation of advanced glycation end products is increased in patients with an abdominal aortic aneurysm

    NARCIS (Netherlands)

    Boersema, Jeltje; de Vos, Lisanne C.; Links, Thera P.; Mulder, Douwe J.; Smit, Andries J.; Zeebregts, Clark J.; Lefrandt, Joop D.

    2017-01-01

    Objective: Advanced glycation end products (AGEs) are implicated in the pathogenesis of cardiovascular disease. Accumulation of AGEs is driven by oxidative or glycemic stress and can be assessed by skin autofluorescence (SAF). SAF is increased in patients with peripheral artery disease (PAD) and

  3. Kinetics of fatty acid binding ability of glycated human serum albumin

    Indian Academy of Sciences (India)

    Unknown

    (Shapiro et al 1980), membrane collagen (Bailey et al. 1976), human serum albumin (HAS) (Iberg and Flückiger. 1986), and lens crystallin (Lyons et al 1991) ..... were reduced by NaBH4 and hydrolyzed by 6 N HCl containing. 1% wt/v phenol. Relative amount of residual lysine residues. (%) in glycated HSA were expressed ...

  4. Anti-glycative effects of oleanolic acid and ursolic acid in kidney of diabetic mice.

    Science.gov (United States)

    Wang, Zhi-hong; Hsu, Cheng-chin; Huang, Chien-ning; Yin, Mei-chin

    2010-02-25

    Inhibitory effects of oleanolic acid (OA) and ursolic acid (UA) on aldose reductase (AR) and glycative products in kidney of diabetic mice were examined. OA or UA at 0.05, 0.1 or 0.2% was supplied for 10 weeks. Diabetic mice with 0.1 or 0.2% OA or UA treatments had significantly higher body weight and lower kidney weight at weeks 5 and 10 (Pcontent in the kidney, dose-dependently decreased plasma glucose, HbA1c, renal N(epsilon)-(carboxymethyl)lysine, urinary glycated albumin and urinary albumin levels; elevated plasma insulin and renal creatinine clearance levels; as well as decreased renal sorbitol and fructose concentrations (P<0.05). OA or UA treatments at 0.1 and 0.2% also significantly diminished renal AR activity and dose-dependently down-regulated renal AR mRNA expression (P<0.05). These two compounds at 0.2% significantly reduced renal sorbitol dehydrogenase activity (P<0.05). OA, not UA, treatments at 0.1 or 0.2% dose-dependently enhanced renal glyoxalase I (GLI) activity, up-regulated renal GLI mRNA expression and lowered renal methylglyoxal level (P<0.05). Based on these marked anti-glycative effects, the supplement of OA or UA might be helpful for the prevention or alleviation of glycation associated renal diseases.

  5. Cell Penetrating Peptides and Cationic Antibacterial Peptides

    Science.gov (United States)

    Rodriguez Plaza, Jonathan G.; Morales-Nava, Rosmarbel; Diener, Christian; Schreiber, Gabriele; Gonzalez, Zyanya D.; Lara Ortiz, Maria Teresa; Ortega Blake, Ivan; Pantoja, Omar; Volkmer, Rudolf; Klipp, Edda; Herrmann, Andreas; Del Rio, Gabriel

    2014-01-01

    Cell penetrating peptides (CPP) and cationic antibacterial peptides (CAP) have similar physicochemical properties and yet it is not understood how such similar peptides display different activities. To address this question, we used Iztli peptide 1 (IP-1) because it has both CPP and CAP activities. Combining experimental and computational modeling of the internalization of IP-1, we show it is not internalized by receptor-mediated endocytosis, yet it permeates into many different cell types, including fungi and human cells. We also show that IP-1 makes pores in the presence of high electrical potential at the membrane, such as those found in bacteria and mitochondria. These results provide the basis to understand the functional redundancy of CPPs and CAPs. PMID:24706763

  6. Characterisation of Maillard reaction products derived from LEKFD--a pentapeptide found in β-lactoglobulin sequence, glycated with glucose--by tandem mass spectrometry, molecular orbital calculations and gel filtration chromatography coupled with continuous photodiode array.

    Science.gov (United States)

    Yamaguchi, Keiko; Homma, Takeshi; Nomi, Yuri; Otsuka, Yuzuru

    2014-02-15

    Maillard reaction peptides (MRPs) contribute to taste, aroma, colour, texture and biological activity. However, peptide degradation or the cross-linking of MRPs in the Maillard reaction has not been investigated clearly. A peptide of LEKFD, a part of β-lactoglobulin, was heated at 110 °C for 24h with glucose and the reaction products were analysed by HPLC with ODS, ESI-MS, ESI-MS/MS and HPLC with gel-filtration column and DAD detector. In the HPLC fractions, an imminium ion of LEK*FD, a pyrylium ion or a hydroxymethyl furylium ion of LEK*FD, and KFD and EK were detected by ESI-MS. Therefore, those products may be produced by the Maillard reaction. The molecular orbital of glycated LEKFD at the lysine epsilon-amino residue with Schiff base form was calculated by MOPAC. HPLC with gel-filtration column showed cross-linking and degradation of peptides. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Plant peptide hormone signalling.

    Science.gov (United States)

    Motomitsu, Ayane; Sawa, Shinichiro; Ishida, Takashi

    2015-01-01

    The ligand-receptor-based cell-to-cell communication system is one of the most important molecular bases for the establishment of complex multicellular organisms. Plants have evolved highly complex intercellular communication systems. Historical studies have identified several molecules, designated phytohormones, that function in these processes. Recent advances in molecular biological analyses have identified phytohormone receptors and signalling mediators, and have led to the discovery of numerous peptide-based signalling molecules. Subsequent analyses have revealed the involvement in and contribution of these peptides to multiple aspects of the plant life cycle, including development and environmental responses, similar to the functions of canonical phytohormones. On the basis of this knowledge, the view that these peptide hormones are pivotal regulators in plants is becoming increasingly accepted. Peptide hormones are transcribed from the genome and translated into peptides. However, these peptides generally undergo further post-translational modifications to enable them to exert their function. Peptide hormones are expressed in and secreted from specific cells or tissues. Apoplastic peptides are perceived by specialized receptors that are located at the surface of target cells. Peptide hormone-receptor complexes activate intracellular signalling through downstream molecules, including kinases and transcription factors, which then trigger cellular events. In this chapter we provide a comprehensive summary of the biological functions of peptide hormones, focusing on how they mature and the ways in which they modulate plant functions. © 2015 Authors; published by Portland Press Limited.

  8. Using an enzymatic galactose assay to detect lactose glycation extents of two proteins caseinate and soybean protein isolate via the Maillard reaction.

    Science.gov (United States)

    Wang, Xiao-Peng; Zhao, Xin-Huai

    2017-06-01

    Glycation of food proteins via the Maillard reaction has been widely studied in the recent years; however, the amount of saccharide connected to proteins is usually not determined. An enzymatic galactose assay was proposed firstly in this study to detect lactose glycation extents of caseinate and soybean protein isolate (SPI) during the Maillard reaction at two temperatures and different times. The separated glycated proteins were hydrolysed to release galactose necessary for the enzymatic assay and glycation calculation. Caseinate and SPI both obtained the highest lactose glycation extents at 100 °C or 121 °C by a reaction time of 180 or 20 min. Short- and long-time reaction resulted in lower glycation extents. During the reaction, three chemical indices (absorbences at 294/490 nm and fluorescence intensities) of reaction mixtures increased continually, but another index reactable NH 2 of glycated proteins showed the opposite trend. In general, changing profiles of the four indices were inconsistent with those profiles of lactose glycation extents of glycated proteins, implying practical limitation of the four indices in studies. This proposed enzymatic assay could directly detect lactose glycation of the two proteins, and thus was more useful than the four chemical indices to monitor glycation of the two proteins. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  9. Aspirin-mediated acetylation of haemoglobin increases in presence of high glucose concentration and decreases protein glycation

    Directory of Open Access Journals (Sweden)

    Francesco Finamore

    2015-09-01

    Full Text Available Glycation represents the first stage in the development of diabetic complications. Aspirin was shown to prevent sugars reacting with proteins, but the exact mechanism of this interaction was not well defined. We performed a quantitative analysis to calculate the levels of acetylation and glycation of haemoglobin, among others red blood cell (RBC proteins, using a label free approach. After glucose incubation, increases in the acetylation levels were seen for several haemoglobin subunits, while a parallel decrease of their glycation levels was observed after aspirin incubation. These results suggest that, a mutual influence between these two modifications, occur at protein level.

  10. Antimicrobial Peptides in Reptiles

    Science.gov (United States)

    van Hoek, Monique L.

    2014-01-01

    Reptiles are among the oldest known amniotes and are highly diverse in their morphology and ecological niches. These animals have an evolutionarily ancient innate-immune system that is of great interest to scientists trying to identify new and useful antimicrobial peptides. Significant work in the last decade in the fields of biochemistry, proteomics and genomics has begun to reveal the complexity of reptilian antimicrobial peptides. Here, the current knowledge about antimicrobial peptides in reptiles is reviewed, with specific examples in each of the four orders: Testudines (turtles and tortosises), Sphenodontia (tuataras), Squamata (snakes and lizards), and Crocodilia (crocodilans). Examples are presented of the major classes of antimicrobial peptides expressed by reptiles including defensins, cathelicidins, liver-expressed peptides (hepcidin and LEAP-2), lysozyme, crotamine, and others. Some of these peptides have been identified and tested for their antibacterial or antiviral activity; others are only predicted as possible genes from genomic sequencing. Bioinformatic analysis of the reptile genomes is presented, revealing many predicted candidate antimicrobial peptides genes across this diverse class. The study of how these ancient creatures use antimicrobial peptides within their innate immune systems may reveal new understandings of our mammalian innate immune system and may also provide new and powerful antimicrobial peptides as scaffolds for potential therapeutic development. PMID:24918867

  11. The association between various smoking behaviors, cotinine biomarkers and skin autofluorescence, a marker for advanced glycation end product accumulation

    NARCIS (Netherlands)

    van Waateringe, Robert P.; Mook-Kanamori, Marjonneke J.; Slagter, Sandra N.; van der Klauw, Melanie M.; van Vliet-Ostaptchouk, Jana V.; Graaff, Reindert; Lutgers, Helen L.; Suhre, Karsten; Selim, Mohammed M. El-Din; Mook-Kanamori, Dennis O.; Wolffenbuttel, Bruce H. R.

    2017-01-01

    BACKGROUND: Skin autofluorescence, a biomarker for advanced glycation end products (AGEs) accumulation, has been shown to predict diabetes-related cardiovascular complications and is associated with several environmental and lifestyle factors. In the present study, we examined the association

  12. Insulin C-peptide test

    Science.gov (United States)

    C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin the body produces and insulin someone injects ...

  13. Maillard Proteomics: Opening New Pages

    Directory of Open Access Journals (Sweden)

    Alena Soboleva

    2017-12-01

    Full Text Available Protein glycation is a ubiquitous non-enzymatic post-translational modification, formed by reaction of protein amino and guanidino groups with carbonyl compounds, presumably reducing sugars and α-dicarbonyls. Resulting advanced glycation end products (AGEs represent a highly heterogeneous group of compounds, deleterious in mammals due to their pro-inflammatory effect, and impact in pathogenesis of diabetes mellitus, Alzheimer’s disease and ageing. The body of information on the mechanisms and pathways of AGE formation, acquired during the last decades, clearly indicates a certain site-specificity of glycation. It makes characterization of individual glycation sites a critical pre-requisite for understanding in vivo mechanisms of AGE formation and developing adequate nutritional and therapeutic approaches to reduce it in humans. In this context, proteomics is the methodology of choice to address site-specific molecular changes related to protein glycation. Therefore, here we summarize the methods of Maillard proteomics, specifically focusing on the techniques providing comprehensive structural and quantitative characterization of glycated proteome. Further, we address the novel break-through areas, recently established in the field of Maillard research, i.e., in vitro models based on synthetic peptides, site-based diagnostics of metabolism-related diseases (e.g., diabetes mellitus, proteomics of anti-glycative defense, and dynamics of plant glycated proteome during ageing and response to environmental stress.

  14. Regulation of human mononuclear phagocyte migration by cell surface-binding proteins for advanced glycation end products.

    OpenAIRE

    Schmidt, A M; Yan, S D; Brett, J; Mora, R; Nowygrod, R; Stern, D

    1993-01-01

    Nonenzymatic glycation of proteins occurs at an accelerated rate in diabetes and can lead to the formation of advanced glycation end products of proteins (AGEs), which bind to mononuclear phagocytes (MPs) and induce chemotaxis. We have isolated two cell surface-associated binding proteins that mediate the interaction of AGEs with bovine endothelial cells. One of these proteins is a new member of the immunoglobulin superfamily of receptors (termed receptor for AGEs or RAGE); and the second is ...

  15. Effect of dietary advanced glycation end products on postprandial appetite, inflammation, and endothelial activation in healthy overweight individuals

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe; Bak, Monika Judyta; Andersen, Jeanette Marker

    2014-01-01

    Advanced glycation end products (AGEs) formed in food during high-heat cooking may induce overeating and inflammation. We investigated whether AGE contents in a single meal affect postprandial appetite and markers of inflammation, endothelial activation, and oxidative stress.......Advanced glycation end products (AGEs) formed in food during high-heat cooking may induce overeating and inflammation. We investigated whether AGE contents in a single meal affect postprandial appetite and markers of inflammation, endothelial activation, and oxidative stress....

  16. Investigation of antioxidant and anti-glycation properties of essential oils from fruits and branchlets of Juniperus oblonga

    Directory of Open Access Journals (Sweden)

    Seyed A. Emami

    2012-04-01

    Full Text Available Plants represent the best and most extensively studied source of natural antioxidants. The present study investigated the antioxidant and anti-glycation properties of different concentrations of essential oils obtained from fruits and branchlets of Juniperus oblonga M. Bieb., Cupressaceae, using different assays. The essential oils were obtained by steam distillation of the branchlets of male tree (BMT, branchlets of female tree (BFT and fruits of J. oblonga. Compositional analysis of oils was performed using a gas chromatography-mass method. Antioxidant activity was assessed using linoleic acid peroxidation, peroxyl radical mediated hemolysis of red blood cells (RBC and low-density lipoprotein (LDL oxidation assays. Anti-glycation properties of oils were evaluated using hemoglobin and insulin glycation assays. Seventeen, eighteen and fifteen compounds were identified in the BMT, BFT and fruit oil, which represented 82.51, 55.69 and 96.89% of the total oils, respectively. α-Pinene was the major component of all three oils. All three oils possessed antioxidant effects against LDL oxidation, linoleic acid peroxidation and peroxyl radical mediated RBC hemolysis. Anti-glycation activities against hemoglobin and insulin glycation were also observed from all tested oils. Overall, there was no unique pattern of dose-dependence for the antioxidant properties of oils in different employed systems. The findings of this study suggest that essential oils from fruits and branchlets of J. oblonga possess antioxidant and anti-glycation properties. Therefore, these oils might be of therapeutic efficacy against diabetes and cardiovascular disease.

  17. Soluble Receptor for Advanced Glycation End Product: A Biomarker for Acute Coronary Syndrome

    Directory of Open Access Journals (Sweden)

    Louise J. N. Jensen

    2015-01-01

    Full Text Available The receptor of advanced glycation end products (RAGE and its ligands are linked to the pathogenesis of coronary artery disease (CAD, and circulating soluble receptor of advanced glycation end products (sRAGE, reflecting the RAGE activity, is suggested as a potential biomarker. Elevated sRAGE levels are reported in relation to acute ischemia and this review focuses on the role of sRAGE as a biomarker for the acute coronary syndrome (ACS. The current studies demonstrated that sRAGE levels are elevated in relation to ACS, however during a very narrow time period, indicating that the time of sampling needs attention. Interestingly, activation of RAGE may influence the pathogenesis and reflection in sRAGE levels in acute and stable CAD differently.

  18. Advanced glycation end products overload might explain intracellular cobalamin deficiency in renal dysfunction, diabetes and aging.

    Science.gov (United States)

    Obeid, Rima; Shannan, Batool; Herrmann, Wolfgang

    2011-11-01

    Advanced glycation end products (AGEs) contribute to aging. Cobalamin (Cbl) is required for cell growth and functions, and its deficiency causes serious complications. Diabetics and renal patients show high concentrations of Cbl, but metabolic evidence of Cbl deficiency that is reversible after Cbl treatment. Cbl might be sequestered in blood and cannot be delivered to the cell. Megalin mediates the uptake of transcobalamin-Cbl complex into the proximal tubule cells. Megalin is involved in the uptake and degradation of AGEs. In aging, diabetes or renal dysfunction, AGEs might overload megalin thus lowering Cbl uptake. Transcobalamin-Cbl might retain in blood. Shedding of megalin and transcobalamin receptor under glycation conditions is also a possible mechanism of this phenomenon. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Glycated haemoglobin may in future be reported as estimated mean blood glucose concentration--secondary publication

    DEFF Research Database (Denmark)

    Borg, R.; Nerup, J.; Nathan, D.M.

    2009-01-01

    Glycated haemoglobin (HbA 1c ) is widely used to determine levels of chronic glycaemia, to judge the adequacy of diabetes treatment and to adjust therapy. HbA 1c results are expressed as the percentage of HbA that is glycated. Day-to-day management is guided by self-monitoring of capillary glucose...... concentrations in mmol/l. The ADAG study determined the relationship between HbA 1c and average glucose concentration (AG) and concluded that for most patients with diabetes, HbA 1c can - with reasonable precision - be expressed as an estimated AG in the same units as self-monitoring Udgivelsesdato: 2009/11/2...

  20. Characteristics and enhanced antioxidant activity of glycated Morchella esculenta protein isolate

    Directory of Open Access Journals (Sweden)

    Qiang ZHANG

    Full Text Available Abstract Morchella esculenta (L Pers. is a highly valued edible and medicinal fungus that remains underutilized. For this study, the effects of glycation treatment on antioxidant activity and characteristics of the M. esculenta protein isolate (MPI were investigated via the Maillard reaction. Conjugation between MPI and xylose was proven via UV-vis, FT-IR, intrinsic fluorescence analysis, and SDS-PAGE. Amino acid analysis revealed involvement of lysine, arginine and tyrosine in MPI, forming a covalent cross-link with xylose. Differential scanning calorimetry (DSC results showed that glycated MPI (MPIG possesses a more favorable thermal stability compared to native MPI (MPIN, heated MPI (MPIH and an unheated mixture of MPI and xylose (MPI-XM. MPIG exhibited significantly enhanced antioxidant activity compared to MPIN, MPIH, and MPI-XM. These results indicate MPIG can serve as a promising novel source of nutraceutical and functional ingredients that exert antioxidant activity.

  1. Statins stimulate the production of a soluble form of the receptor for advanced glycation end products

    OpenAIRE

    Quade-Lyssy, Patricia; Kanarek, Anna Maria; Baiersdörfer, Markus; Postina, Rolf; Kojro, Elzbieta

    2013-01-01

    The beneficial effects of statin therapy in the reduction of cardiovascular pathogenesis, atherosclerosis, and diabetic complications are well known. The receptor for advanced glycation end products (RAGE) plays an important role in the progression of these diseases. In contrast, soluble forms of RAGE act as decoys for RAGE ligands and may prevent the development of RAGE-mediated disorders. Soluble forms of RAGE are either produced by alternative splicing [endogenous secretory RAGE (esRAGE)] ...

  2. Fluorescent advanced glycation end products in the detection of factual stages of cartilage degeneration

    Czech Academy of Sciences Publication Activity Database

    Handl, M.; Filová, Eva; Kubala, M.; Lánský, Z.; Koláčná, Lucie; Vorlíček, Jaroslav; Trč, T.; Amler, Evžen

    2007-01-01

    Roč. 56, č. 2 (2007), s. 235-242 ISSN 0862-8408 R&D Projects: GA AV ČR(CZ) 1ET400110403; GA AV ČR(CZ) IAA500390702 Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z50110509 Keywords : Nonenzymic glycation * Cartilage * Knee joint Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.505, year: 2007

  3. Advanced glycation endproducts induce podocyte apoptosis by activation of the FOXO4 transcription factor

    OpenAIRE

    Chuang, PY; Yu, Q; Fang, W; Uribarri, J; He, JC

    2007-01-01

    Advanced glycation endproducts (AGEs) and a receptor for AGEs (RAGE) have been linked in the pathogenesis of diabetic nephropathy. RAGE is usually localized to podocytes and is increased in diabetes. RAGE activation increases reactive oxygen species production, which mediates hyperglycemia-induced podocyte apoptosis in early diabetic nephropathy. Here, we examined the interaction of AGE and RAGE on podocyte apoptosis. When we exposed murine cultured podocytes to bovine serum albumin (BSA) tha...

  4. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts

    OpenAIRE

    Li,D.X.; Deng,T.Z.; Lv,J.; Ke,J.

    2014-01-01

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts t...

  5. Advanced glycation end-products: Mechanics of aged collagen from molecule to tissue.

    Science.gov (United States)

    Gautieri, Alfonso; Passini, Fabian S; Silván, Unai; Guizar-Sicairos, Manuel; Carimati, Giulia; Volpi, Piero; Moretti, Matteo; Schoenhuber, Herbert; Redaelli, Alberto; Berli, Martin; Snedeker, Jess G

    2017-05-01

    Concurrent with a progressive loss of regenerative capacity, connective tissue aging is characterized by a progressive accumulation of Advanced Glycation End-products (AGEs). Besides being part of the typical aging process, type II diabetics are particularly affected by AGE accumulation due to abnormally high levels of systemic glucose that increases the glycation rate of long-lived proteins such as collagen. Although AGEs are associated with a wide range of clinical disorders, the mechanisms by which AGEs contribute to connective tissue disease in aging and diabetes are still poorly understood. The present study harnesses advanced multiscale imaging techniques to characterize a widely employed in vitro model of ribose induced collagen aging and further benchmarks these data against experiments on native human tissues from donors of different age. These efforts yield unprecedented insight into the mechanical changes in collagen tissues across hierarchical scales from molecular, to fiber, to tissue-levels. We observed a linear increase in molecular spacing (from 1.45nm to 1.5nm) and a decrease in the D-period length (from 67.5nm to 67.1nm) in aged tissues, both using the ribose model of in vitro glycation and in native human probes. Multiscale mechanical analysis of in vitro glycated tendons strongly suggests that AGEs reduce tissue viscoelasticity by severely limiting fiber-fiber and fibril-fibril sliding. This study lays an important foundation for interpreting the functional and biological effects of AGEs in collagen connective tissues, by exploiting experimental models of AGEs crosslinking and benchmarking them for the first time against endogenous AGEs in native tissue. Copyright © 2016 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

  6. Analysis of glycated hemoglobin A1c by capillary electrophoresis and capillary isoelectric focusing

    Czech Academy of Sciences Publication Activity Database

    Koval, Dušan; Kašička, Václav; Cottet, H.

    2011-01-01

    Roč. 413, č. 1 (2011), s. 8-15 ISSN 0003-2697 R&D Projects: GA ČR GP203/09/P485; GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z40550506 Keywords : capillary zone electrophoresis * capillary isoelectric focusing * glycated hemoglobin HbA1c Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.996, year: 2011

  7. Rifampicin reduces advanced glycation end products and activates DAF-16 to increase lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Golegaonkar, Sandeep; Tabrez, Syed S; Pandit, Awadhesh; Sethurathinam, Shalini; Jagadeeshaprasad, Mashanipalya G; Bansode, Sneha; Sampathkumar, Srinivasa-Gopalan; Kulkarni, Mahesh J; Mukhopadhyay, Arnab

    2015-06-01

    Advanced glycation end products (AGEs) are formed when glucose reacts nonenzymatically with proteins; these modifications are implicated in aging and pathogenesis of many age-related diseases including type II diabetes, atherosclerosis, and neurodegenerative disorders. Thus, pharmaceutical interventions that can reduce AGEs may delay age-onset diseases and extend lifespan. Using LC-MS(E), we show that rifampicin (RIF) reduces glycation of important cellular proteins in vivo and consequently increases lifespan in Caenorhabditis elegans by up to 60%. RIF analog rifamycin SV (RSV) possesses similar properties, while rifaximin (RMN) lacks antiglycation activity and therefore fails to affect lifespan positively. The efficacy of RIF and RSV as potent antiglycating agents may be attributed to the presence of a p-dihydroxyl moiety that can potentially undergo spontaneous oxidation to yield highly reactive p-quinone structures, a feature absent in RMN. We also show that supplementing rifampicin late in adulthood is sufficient to increase lifespan. For its effect on longevity, rifampicin requires DAF-18 (nematode PTEN) as well as JNK-1 and activates DAF-16, the FOXO homolog. Interestingly, the drug treatment modulates transcription of a different subset of DAF-16 target genes, those not controlled by the conserved Insulin-IGF-1-like signaling pathway. RIF failed to increase the lifespan of daf-16 null mutant despite reducing glycation, showing thereby that DAF-16 may not directly affect AGE formation. Together, our data suggest that the dual ability to reduce glycation in vivo and activate prolongevity processes through DAF-16 makes RIF and RSV effective lifespan-extending interventions. © 2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  8. Anti-glycated and antiradical activities in vitro of polysaccharides from Ganoderma capense

    OpenAIRE

    Yan, Chunyan; Kong, Fansheng; Zhang, Dezhi; Cui, Jiangxia

    2013-01-01

    Background : Ganoderma capense is a Ganoderma species and is widely used, especially in Asia, as a well-known medicinal mushroom for health-promoting effect and for treatment of chronic diseases, such as diabetes, aging, etc. G. capense is rich of polysaccharide. Objective: To isolate the polysaccharides from G. capense and evaluate their anti-glycated and antiradical activities in vitro. Materials and Methods : The dried powder of submerged fermentation culturing mycelium of G. capense was d...

  9. Receptor for advanced glycation endproducts (RAGE) maintains pulmonary structure and regulates the response to cigarette smoke

    OpenAIRE

    Wolf, Lisa; Herr, Christian; Niederstra?er, Julia; Beisswenger, Christoph; Bals, Robert

    2017-01-01

    The receptor for advanced glycation endproducts (RAGE) is highly expressed in the lung but its physiological functions in this organ is still not completely understood. To determine the contribution of RAGE to physiological functions of the lung, we analyzed pulmonary mechanics and structure of wildtype and RAGE deficient (RAGE-/-) mice. RAGE deficiency spontaneously resulted in a loss of lung structure shown by an increased mean chord length, increased respiratory system compliance, decrease...

  10. Advanced glycation end products regulate interleukin-1? production in human placenta

    OpenAIRE

    SENO, Kotomi; SASE, Saoko; OZEKI, Ayae; TAKAHASHI, Hironori; OHKUCHI, Akihide; SUZUKI, Hirotada; MATSUBARA, Shigeki; IWATA, Hisataka; KUWAYAMA, Takehito; SHIRASUNA, Koumei

    2017-01-01

    Maternal obesity is a major risk factor for pregnancy complications, causing inflammatory cytokine release in the placenta, including interleukin-1? (IL-1?), IL-6, and IL-8. Pregnant women with obesity develop accelerated systemic and placental inflammation with elevated circulating advanced glycation end products (AGEs). IL-1? is a pivotal inflammatory cytokine associated with obesity and pregnancy complications, and its production is regulated by NLR family pyrin domain-containing 3 (NLRP3)...

  11. Monitoring of malting process by characterization of glycation of barley protein Z

    Czech Academy of Sciences Publication Activity Database

    Bobálová, Janette; Petry-Podgorska, Inga; Laštovičková, Markéta; Chmelík, Josef

    2010-01-01

    Roč. 230, č. 4 (2010), s. 665-673 ISSN 1438-2377 R&D Projects: GA MŠk 1M0570; GA MŠk 1M06030; GA MŠk MEB040807 Institutional research plan: CEZ:AV0Z40310501 Keywords : malting * MALDI-TOF MS * glycation Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.585, year: 2010

  12. Advanced glycation end-products induce heparanase expression in endothelial cells by the receptor for advanced glycation end products and through activation of the FOXO4 transcription factor.

    Science.gov (United States)

    An, Xiao-Fei; Zhou, Lei; Jiang, Peng-Jun; Yan, Ming; Huang, Yu-Jun; Zhang, Su-Na; Niu, Yun-Fei; Ten, Shi-Chao; Yu, Jiang-Yi

    2011-08-01

    As an endo-β (1-4)-D: -glucuronidase, heparanase can specifically cleave carbohydrate chains of heparan sulfate (HS) and has been implicated in development of endothelial cells dsyfunction. The advanced glycation end products (AGEs) play a pivotal role in the pathology of diabetic complications. In the present study, we investigated the effect of AGE-bovine serum albumin (AGE-BSA) on heparanase expression in human microvascular endothelial cells (HMVECs) and the underlying molecular mechanisms. The results indicated that in vitro direct exposure of HMVECs to AGE-BSA (300, 1000, and 3000 μg/ml) could increase heparanase mRNA and protein expression in a dose and time-dependent manner. The effect of 1000 μg/ml AGE-BSA could be abolished by neutralization with antibody of the receptor for advanced glycation end products (RAGE). Moreover, pretreatment with inhibitors of nuclear factor-κB (NF-κB) or PI3-kinase did not affect heparanase expression induced by AGE-BSA. Nevertheless, small interference RNA (siRNA) for transcriptional factor FOXO4 could reduce the increase of heparanase expression in HMVECs induced by 1000 μg/ml AGE-BSA. These results suggest that AGEs could induce heparanase expression in HMVECs by RAGE and predominantly through activation of the FOXO4 transcription factor.

  13. Effects of salt concentration on the reaction rate of Glc with amino acids, peptides, and proteins.

    Science.gov (United States)

    Yamaguchi, Keiko; Noumi, Yuri; Nakajima, Katsumi; Nagatsuka, Chiharu; Aizawa, Haruko; Nakawaki, Rie; Mizude, Eri; Otsuka, Yuzuru; Homma, Takeshi; Chuyen, Nguyen Van

    2009-11-01

    The reaction between the amino group and the carbonyl group is important in food quality control. Furthermore, advanced glycation end products from foods are considered to relate to aging and diabetes. Thus, it is important to control this reaction. In this study, we investigated the effects of salt concentration on the rates of browning reaction of amino acid, peptides, and proteins. A high concentration of sodium chloride retarded the reaction rate of Glc with amino acids as measured with the absorbance at 470 nm, but did not change the browning rate of Glc with peptides. On the other hand, sodium chloride retarded the browning reaction rate of proteins as measured with polymerization degree or by the loss of Lys. It is hoped that the results of this study will be applied in the control of amino-carbonyl reaction rates in the food industry.

  14. Serum glycated albumin as a glycemic control marker in diabetic cats.

    Science.gov (United States)

    Mori, Akihiro; Lee, Peter; Mizutani, Hisashi; Takahashi, Tomoya; Azakami, Daigo; Mizukoshi, Mina; Fukuta, Hiroko; Sakusabe, Noriko; Sakusabe, Arihito; Kiyosawa, Yoshio; Arai, Toshiro; Sako, Toshinori

    2009-01-01

    Measurements of glycated proteins such as serum fructosamine, glycated hemoglobin, and glycated albumin (GA) are increasingly used to complement serum glucose concentration for better management of diabetes mellitus. For example, the degree of glycemic control in diabetic cats can be determined by evaluating fructosamine concentration. Unfortunately, fructosamine tests are currently not performed in Japan, and as such, the measurement of GA may serve as a replacement test. The objectives of the current study were 2-fold. First, serum GA and fructosamine level were evaluated for positive correlation in cats as a preliminary gauge on whether serum GA use is applicable. Second, a GA percentage reference range was determined from healthy control cats for possible future diagnostic use. A positive correlation was determined for fructosamine and GA in both normal and diabetic cats. Moreover, the serum GA percentage reference interval based on control cats was determined to be 7.5-13.9% (95% nonparametric interfractile interval). Interestingly, no significant difference in serum GA percentages was observed between samples from diabetic cats with excellent glycemic control and control cats. However, good, fair, and poor glycemic control diabetic cats resulted in a significant increase in serum GA percentages in comparison to control cats. Therefore, these results indicate that serum GA may be a useful glycemic control indicator that could substitute for fructosamine to monitor glycemic control in diabetic cats.

  15. Improved glucose control and reduced body weight in rodents with dual mechanism of action peptide hybrids.

    Directory of Open Access Journals (Sweden)

    James L Trevaskis

    Full Text Available Combination therapy is being increasingly used as a treatment paradigm for metabolic diseases such as diabetes and obesity. In the peptide therapeutics realm, recent work has highlighted the therapeutic potential of chimeric peptides that act on two distinct receptors, thereby harnessing parallel complementary mechanisms to induce additive or synergistic benefit compared to monotherapy. Here, we extend this hypothesis by linking a known anti-diabetic peptide with an anti-obesity peptide into a novel peptide hybrid, which we termed a phybrid. We report on the synthesis and biological activity of two such phybrids (AC164204 and AC164209, comprised of a glucagon-like peptide-1 receptor (GLP1-R agonist, and exenatide analog, AC3082, covalently linked to a second generation amylin analog, davalintide. Both molecules acted as full agonists at their cognate receptors in vitro, albeit with reduced potency at the calcitonin receptor indicating slightly perturbed amylin agonism. In obese diabetic Lep(ob/Lep (ob mice sustained infusion of AC164204 and AC164209 reduced glucose and glycated haemoglobin (HbA1c equivalently but induced greater weight loss relative to exenatide administration alone. Weight loss was similar to that induced by combined administration of exenatide and davalintide. In diet-induced obese rats, both phybrids dose-dependently reduced food intake and body weight to a greater extent than exenatide or davalintide alone, and equal to co-infusion of exenatide and davalintide. Phybrid-mediated and exenatide + davalintide-mediated weight loss was associated with reduced adiposity and preservation of lean mass. These data are the first to provide in vivo proof-of-concept for multi-pathway targeting in metabolic disease via a peptide hybrid, demonstrating that this approach is as effective as co-administration of individual peptides.

  16. Protective Role of PEDF-Derived Synthetic Peptide Against Experimental Diabetic Nephropathy.

    Science.gov (United States)

    Ishibashi, Y; Matsui, T; Taira, J; Higashimoto, Y; Yamagishi, S

    2016-09-01

    Pigment epithelium-derived factor (PEDF) is a glycoprotein with complex neuroprotective, anti-angiogenic, and anti-inflammatory properties, all of which could potentially be exploited as a therapeutic option for vascular complications in diabetes. We have previously shown that PEDF-derived synthetic peptide, P5-3 (FIFVLRD) has a comparable ability with full PEDF protein to inhibit rat corneal neovascularization induced by chemical cauterization. However, the effects of PEDF peptide on experimental diabetic nephropathy remain unknown. To address the issue, we modified P5-3 to stabilize and administered the modified peptide (d-Lys-d-Lys-d-Lys-Gln-d-Pro-P5-3-Cys-amide, 0.2 nmol/day) or vehicle to streptozotocin-induced diabetic rats (STZ-rats) intraperitoneally by an osmotic mini pump for 2 weeks. We further examined the effects of modified peptide on human proximal tubular cells. Renal PEDF expression was decreased in STZ-rats. Although the peptide administration did not affect blood glucose or blood pressure, it decreased urinary excretion levels of 8-hydroxy-2'-deoxyguanosine, an oxidative stress marker, and reduced plasminogen activator inhibitor-1 (PAI-1) gene expression, and suppressed glomerular expansion in the diabetic kidneys. High glucose or advanced glycation end products stimulated oxidative stress generation and PAI-1 gene expression in tubular cells, all of which were significantly suppressed by 10 nM modified P5-3 peptide. Our present study suggests that PEDF-derived synthetic modified peptide could protect against experimental diabetic nephropathy and inhibit tubular cell damage under diabetes-like conditions through its anti-oxidative properties. Supplementation of modified P5-3 peptide may be a novel therapeutic strategy for diabetic nephropathy. © Georg Thieme Verlag KG Stuttgart · New York.

  17. The effect of glycation on bovine serum albumin conformation and ligand binding properties with regard to gliclazide

    Science.gov (United States)

    Żurawska-Płaksej, Ewa; Rorbach-Dolata, Anna; Wiglusz, Katarzyna; Piwowar, Agnieszka

    2018-01-01

    Albumin, the major serum protein, plays a variety of functions, including binding and transporting endogenous and exogenous ligands. Its molecular structure is sensitive to different environmental modifiers, among which glucose is one of the most significant. In vivo albumin glycation occurs under physiological conditions, but it is increased in diabetes. Since bovine serum albumin (BSA) may serve as a model protein in in vitro experiments, we aimed to investigate the impact of glucose-mediated BSA glycation on the binding capacity towards gliclazide, as well as the ability of this drug to prevent glycation of the BSA molecule. To reflect normo- and hyperglycemia, the conditions of the glycation process were established. Structural changes of albumin after interaction with gliclazide (0-14 μM) were determined using fluorescence quenching and circular dichroism spectroscopy. Moreover, thermodynamic parameters as well as energy transfer parameters were determined. Calculated Stern-Volmer quenching constants, as well as binding constants for the BSA-gliclazide complex, were lower for the glycated form of albumin than for the unmodified protein. The largest, over 2-fold, decrease in values of binding parameters was observed for the sample with 30 mM of glucose, reflecting the poorly controlled diabetic state, which indicates that the degree of glycation had a critical influence on binding with gliclazide. In contrast to significant changes in the tertiary structure of BSA upon binding with gliclazide, only slight changes in the secondary structure were observed, which was reflected by about a 3% decrease of the α-helix content of glycated BSA (regardless of glucose concentration) in comparison to unmodified BSA. The presence of gliclazide during glycation did not affect its progress. The results of this study indicate that glycation significantly changed the binding ability of BSA towards gliclazide and the scale of these changes depended on glucose concentration. It

  18. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class...... of antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which...

  19. Glycation of human high density lipoprotein by methylglyoxal: effect on HDL-paraoxonase activity.

    Science.gov (United States)

    Bacchetti, Tiziana; Masciangelo, Simona; Armeni, Tatiana; Bicchiega, Virginia; Ferretti, Gianna

    2014-03-01

    Methylglyoxal (MG), a reactive carbonyl compound formed primarily from triose phosphates, appears to be involved in the molecular mechanisms of diabetes, end-stage renal disease and neurodegenerative diseases. Methylglyoxal exerts several biological activities. Among these it promotes advanced glycation end products (AGEs), which are crucial in pathogenesis of human disease. Previous studies have demonstrated that MG reacts with proteins and compositional modifications reflect loss of biological activity. The aim of the study was to investigate the effect of in vitro MG-induced glycation on human high density lipoprotein (HDL) and on the activity of the enzyme paraoxonase-1 (PON1). HDL was incubated in the absence or in the presence of MG (0.2mmol/L and 1.0mmol/L) (MG-HDL) for different times (3, 6, 24h) at 37° C. We evaluated apoprotein compositional changes, in both control and MG treated HDL, using intrinsic fluorescence of tryptophan and monitoring the decrease of free amino groups. Furthermore we evaluated fluorescent advanced glycation end products (Ex=370nm, Em=440nm) and the activity of HDL-paraoxonase. We demonstrated that human HDL is susceptible to glycation by MG (0.2mmol/L and 1mmol/L). The decrease of free amino groups and of intrinsic fluorescence of tryptophan demonstrates HDL apoprotein modifications in HDL incubated with MG. The compositional changes are associated with a significant increase in fluorescent advanced glycation end products and with a significant decrease of paraoxonase-1 enzyme activity associated with the HDL surface. HDL-associated paraoxonase is responsible for the anti-inflammatory and anti-oxidative properties of HDL and detoxification against homocysteine-thiolactone. Therefore, modifications of apoprotein composition and the decrease of paraoxonase-1 activity in MG-treated HDL could affect the protective effect exerted by HDL against oxidative damage and could contribute to complications in patients affected by diseases

  20. Voltammetric Detection of S100B Protein Using His-Tagged Receptor Domains for Advanced Glycation End Products (RAGE Immobilized onto a Gold Electrode Surface

    Directory of Open Access Journals (Sweden)

    Edyta Mikuła

    2014-06-01

    Full Text Available In this work we report on an electrochemical biosensor for the determination of the S100B protein. The His-tagged VC1 domains of Receptors for Advanced Glycation End (RAGE products used as analytically active molecules were covalently immobilized on a monolayer of a thiol derivative of pentetic acid (DPTA complex with Cu(II deposited on a gold electrode surface. The recognition processes between the RAGE VC1 domain and the S100B protein results in changes in the redox activity of the DPTA-Cu(II centres which were measured by Osteryoung square-wave voltammetry (OSWV. In order to verify whether the observed analytical signal originates from the recognition process between the His6–RAGE VC1 domains and the S100B protein, the electrode modified with the His6–RAGE C2 and His6–RAGE VC1 deleted domains which have no ability to bind S100B peptides were applied. The proposed biosensor was quite sensitive, with a detection limit of 0.52 pM recorded in the buffer solution. The presence of diluted human plasma and 10 nM Aβ1-40 have no influence on the biosensor performance.

  1. Tumor penetrating peptides

    Directory of Open Access Journals (Sweden)

    Tambet eTeesalu

    2013-08-01

    Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular zip code of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is

  2. Tumor-Penetrating Peptides

    Science.gov (United States)

    Teesalu, Tambet; Sugahara, Kazuki N.; Ruoslahti, Erkki

    2013-01-01

    Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC), contains the integrin-binding RGD motif. RGD mediates tumor-homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR) motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular “zip code” of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies, and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is present in the

  3. Novel Endogenous Antimicrobial Peptides

    OpenAIRE

    Nordahl, Emma

    2009-01-01

    Antimicrobial peptides serve as a first line of defence against invading microorganisms and are an essential part of our fast innate immune system. They are ancient molecules found in all classes of life. Antimicrobial peptides rapidly kill a broad spectrum of microbes and are immunomodulatory, i.e. having additional actions influencing inflammation and other innate immune responses. Results presented in this thesis demonstrate that proteases of common human pathogens degrade and inactivate t...

  4. Glutamine reduces postprandial glycemia and augments the glucagon-like peptide-1 response in type 2 diabetes patients

    DEFF Research Database (Denmark)

    Samocha-Bonet, Dorit; Wong, Olivia; Synnott, Emma-Leigh

    2011-01-01

    Impaired glucagon-like peptide (GLP-1) secretion or response may contribute to ineffective insulin release in type 2 diabetes. The conditionally essential amino acid glutamine stimulates GLP-1 secretion in vitro and in vivo. In a randomized, crossover study, we evaluated the effect of oral...... glutamine, with or without sitagliptin (SIT), on postprandial glycemia and GLP-1 concentration in 15 type 2 diabetes patients (glycated hemoglobin 6.5 ± 0.6%). Participants ingested a low-fat meal (5% fat) after receiving either water (control), 30 g l-glutamine (Gln-30), 15 g L-glutamine (Gln-15), 100 mg...... concentration and limiting postprandial glycemia in type 2 diabetes....

  5. Peptide aldehyde inhibitors of bacterial peptide deformylases.

    Science.gov (United States)

    Durand, D J; Gordon Green, B; O'Connell, J F; Grant, S K

    1999-07-15

    Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity. Copyright 1999 Academic Press.

  6. The Effect of Glycated Hemoglobin and Albumin-Corrected Glycated Serum Protein on Mortality in Diabetic Patients Receiving Continuous Peritoneal Dialysis.

    Science.gov (United States)

    Peng, Fenfen; Xia, Xi; He, Feng; Li, Zhijian; Huang, Fengxian; Yu, Xueqing

    2015-01-01

    To explore the effect of glycated hemoglobin (HbA1c) and albumin-corrected glycated serum proteins (Alb-GSP) on the mortality of diabetic patients receiving continuous peritoneal dialysis (PD). In this single-center retrospective cohort study, incident diabetic PD patients from January 1, 2006, to December 31, 2010, were recruited, and followed up until December 31, 2011. The effect of HbA1c and Alb-GSP on mortality was evaluated by Cox proportional hazards models. A total of 200 patients (60% male, mean age 60.3 ± 10.6 years) with a mean follow-up of 29.0 months (range: 4.3 - 71.5 months) were recruited. Sixty-four patients died during the follow-up period, of whom 21 died of cardiovascular disease (CVD). Mean values for HbA1c, GSP and Alb-GSP were 6.7% (range: 4.1 - 12.5%), 202 μmol/L (range: 69 - 459 μmol/L), and 5.78 μmol/g (range: 2.16 - 14.98 μmol/g), respectively. The concentrations of GSP and Alb-GSP were closely correlated with HbA1c (r = 0.41, p GSP ≤ 4.50 μmol/g had increased all-cause and non-cardiovascular mortality (HR = 2.42, 95% CI: 1.13 - 5.19, p = 0.02; and HR = 2.98, 95% CI: 1.05 - 8.48, p = 0.04 respectively). Increased HbA1c and decreased Alb-GSP may be associated with poorer survival in diabetic PD patients, with a non-significant trend observed for poorer survival with the highest level of Alb-GSP. Copyright © 2015 International Society for Peritoneal Dialysis.

  7. Glycation of collagen: the basis of its central role in the late complications of ageing and diabetes.

    Science.gov (United States)

    Paul, R G; Bailey, A J

    1996-12-01

    The most serious late complication of ageing and diabetes mellitus follow similar patterns in the dysfunction of retinal capillaries, renal tissue, and the cardiovascular system. The changes are accelerated in diabetic patients owing to hyerglycaemia and are the major cause of premature morbidity and mortality. These tissues and their optimal functioning are dependent on the integrity of their supporting framework of collagen. It is the modification of the properties by glycation that results in many of the damaging late complications. Initially glycation affects the interactions of collagen with cells and other matrix components, but the most damaging effects are caused by the formation of glucose-mediated intermolecular cross-links. These cross-links decrease the critical flexibility and permeability of the tissues and reduce turnover. In contrast to the renal and retinal tissue, the cardiovascular system also contains a significant proportion of other fibrous connective tissue protein elastin, and its properties are similarly modified by glycation. The nature of these glycation cross-links is now being unravelled and this knowledge is crucial in any attempt to inhibit these deleterious glycation reactions.

  8. (D)-Ribose supplementation in the equine: lack of effect on glycated plasma proteins suggesting safety in humans.

    Science.gov (United States)

    Sinatra, Stephen T; Caiazzo, Corby

    2015-01-01

    d-Ribose is a popular dietary supplement for humans and the equine because of its crucial role in cellular bioenergetics. However, as a reducing sugar, it has been suggested that ingestion of d-ribose might promote the formation of glycated proteins in vivo with potential adverse consequences. The aim of this study was to examine if d-Ribose would promote the formation of glycated proteins in vivo following exercise in training thoroughbred racehorses. Two groups of horses received the supplement (30 and 50 g d-Ribose daily) for 17 weeks, during which period the horses were subjected to low-intensity exercises followed by high-intensity exercises. Blood samples were analyzed for glycated plasma proteins at baseline and following the 2 exercise regimens. This study shows that long-term ingestion of d-Ribose at 30-50 g a day does not promote the formation of glycated plasma proteins in thoroughbred racehorses. Ribose supplementation also protected the horses from cramping while enhancing muscle recovery at the same time. No adverse effects were reported. Ribose supplementation is safe and does not cause glycation in vivo. This investigation also establishes safety of d-Ribose in thoroughbred racehorses, suggesting similar implications in humans as well.

  9. Reference values for the Chinese population of skin autofluorescence as a marker of advanced glycation end products accumulated in tissue.

    Science.gov (United States)

    Yue, X; Hu, H; Koetsier, M; Graaff, R; Han, C

    2011-07-01

    Advanced glycation end products play an important role in the pathophysiology of several chronic and age-related diseases, especially diabetes mellitus. Skin autofluorescence is a non-invasive method for assessing levels of tissue advanced glycation end products. This study aims to establish the normal reference value of advanced glycation end products accumulated in tissue measured by the advanced glycation end product reader--skin autofluorescence--and discusses some factors influencing it. The values of autofluorescence in healthy individuals in China were determined by the advanced glycation end product reader; age, gender, skin reflectance, smoking habits and alcohol consumption of the subjects were also recorded. The mean reference values of autofluorescence in healthy Chinese subjects are (95% confidence interval) 20-29 years: 1.54-1.62 arbitrary units; 30-39 years: 1.66-1.75; 40-49 years: 1.78-1.89; 50-59 years: 1.87-2.03; 60-69 years: 1.86-2.09; 70-79 years: 1.97-2.31. The value of autofluorescence is strongly related to age, but no significant difference between males and females were found (all P > 0.05). Autofluorescence was higher in smokers than in non-smokers (P reader reliable for lower skin reflections as well, independently of the skin colour. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

  10. Cyanidin-3-O-glucoside functions like chemical chaperone and attenuates the glycation mediated amyloid formation in albumin.

    Science.gov (United States)

    Prasanna, Govindarajan; Jing, Pu

    2018-04-02

    In this study, chemical chaperone like function of cyanidin-3-O-glucoside (C3G) was investigated through fluorescence spectroscopy, UV-visible spectroscopy, circular dichroism spectroscopy, confocal microscopy, scanning electron microscopy and molecular docking studies. Early and advanced glycation inhibitory effect was evaluated by fluorescence spectroscopy and agarose gel electrophoresis. Amyloids were investigated based on their propensity to bind Congo Red (CR) and Thioflavin T (ThT) by multiple microscopic approaches. Circular dichroism studies were used to analyze the changes in the secondary structure due to glycation. C3G effectively inhibited early and advanced glycation by masking like function, carbonyl scavenging and chemical chaperone activity. C3G had molecular interaction with Glu186, Arg427, Ser428, Lys431, Arg435, and Arg458 of BSA. Based on the microscopic analysis, it is evident that C3G can inhibit protein aggregation and amyloid formation. Circular dichroism studies suggested that glycation had resulted in augmented β-sheet propensity, whereas C3G had a protective effect on the helical conformation of BSA. We conclude that C3G has a chemical chaperone like function on the event of glycation mediated amyloid formation in BSA. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Methylglyoxal-derived hydroimidazolone-1 evokes inflammatory reactions in endothelial cells via an interaction with receptor for advanced glycation end products.

    Science.gov (United States)

    Ishibashi, Yuji; Matsui, Takanori; Nakamura, Nobutaka; Sotokawauchi, Ami; Higashimoto, Yuichiro; Yamagishi, Sho-Ichi

    2017-09-01

    Glyceraldehyde-derived advanced glycation end products contribute to vascular inflammation in diabetes. However, what advanced glycation end product structure could evoke inflammatory reactions remains unknown. We examined whether and how methylglyoxal-derived hydroimidazolone 1, one of the advanced glycation end products formed from glyceraldehyde, elicits inflammatory reactions in human umbilical vein endothelial cells. Glyceraldehyde-advanced glycation end products-aptamer was prepared using a systemic evolution of ligands by exponential enrichment. The binding affinities of methylglyoxal-derived hydroimidazolone 1 to receptor for advanced glycation end products or advanced glycation end product-aptamer were measured with a quartz crystal microbalance. Intracellular reactive oxygen species generation and THP-1 cell adhesion were evaluated using fluorescent probes. Gene expression was analysed by reverse transcription polymerase chain reaction. Methylglyoxal-derived hydroimidazolone 1 bound to receptor for advanced glycation end products and advanced glycation end product-aptamer with a dissociation constant ( K d ) of 56.7 µM and 1.51 mM, respectively. Methylglyoxal-derived hydroimidazolone 1 at 100 µg/mL significantly increased reactive oxygen species generation in human umbilical vein endothelial cells, which were attenuated by anti-receptor for advanced glycation end products antibody or advanced glycation end product-aptamer. In all, 100 µg/mL methylglyoxal-derived hydroimidazolone 1 significantly increased receptor for advanced glycation end products and intercellular adhesion molecule-1 messenger RNA levels in, and THP-1 cell adhesion to, human umbilical vein endothelial cells, all of which were blocked by anti-receptor for advanced glycation end products antibody. Our present results indicate that methylglyoxal-derived hydroimidazolone 1 evokes inflammatory reactions in human umbilical vein endothelial cells via receptor for advanced glycation

  12. Granin-derived peptides.

    Science.gov (United States)

    Troger, Josef; Theurl, Markus; Kirchmair, Rudolf; Pasqua, Teresa; Tota, Bruno; Angelone, Tommaso; Cerra, Maria C; Nowosielski, Yvonne; Mätzler, Raphaela; Troger, Jasmin; Gayen, Jaur R; Trudeau, Vance; Corti, Angelo; Helle, Karen B

    2017-07-01

    The granin family comprises altogether 7 different proteins originating from the diffuse neuroendocrine system and elements of the central and peripheral nervous systems. The family is dominated by three uniquely acidic members, namely chromogranin A (CgA), chromogranin B (CgB) and secretogranin II (SgII). Since the late 1980s it has become evident that these proteins are proteolytically processed, intragranularly and/or extracellularly into a range of biologically active peptides; a number of them with regulatory properties of physiological and/or pathophysiological significance. The aim of this comprehensive overview is to provide an up-to-date insight into the distribution and properties of the well established granin-derived peptides and their putative roles in homeostatic regulations. Hence, focus is directed to peptides derived from the three main granins, e.g. to the chromogranin A derived vasostatins, betagranins, pancreastatin and catestatins, the chromogranin B-derived secretolytin and the secretogranin II-derived secretoneurin (SN). In addition, the distribution and properties of the chromogranin A-derived peptides prochromacin, chromofungin, WE14, parastatin, GE-25 and serpinins, the CgB-peptide PE-11 and the SgII-peptides EM66 and manserin will also be commented on. Finally, the opposing effects of the CgA-derived vasostatin-I and catestatin and the SgII-derived peptide SN on the integrity of the vasculature, myocardial contractility, angiogenesis in wound healing, inflammatory conditions and tumors will be discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Peptide Optical waveguides.

    Science.gov (United States)

    Handelman, Amir; Apter, Boris; Shostak, Tamar; Rosenman, Gil

    2017-02-01

    Small-scale optical devices, designed and fabricated onto one dielectric substrate, create integrated optical chip like their microelectronic analogues. These photonic circuits, based on diverse physical phenomena such as light-matter interaction, propagation of electromagnetic waves in a thin dielectric material, nonlinear and electro-optical effects, allow transmission, distribution, modulation, and processing of optical signals in optical communication systems, chemical and biological sensors, and more. The key component of these optical circuits providing both optical processing and photonic interconnections is light waveguides. Optical confinement and transmitting of the optical waves inside the waveguide material are possible due to the higher refractive index of the waveguides in comparison with their surroundings. In this work, we propose a novel field of bionanophotonics based on a new concept of optical waveguiding in synthetic elongated peptide nanostructures composed of ordered peptide dipole biomolecules. New technology of controllable deposition of peptide optical waveguiding structures by nanofountain pen technique is developed. Experimental studies of refractive index, optical transparency, and linear and nonlinear waveguiding in out-of-plane and in-plane diphenylalanine peptide nanotubes have been conducted. Optical waveguiding phenomena in peptide structures are simulated by the finite difference time domain method. The advantages of this new class of bio-optical waveguides are high refractive index contrast, wide spectral range of optical transparency, large optical nonlinearity, and electro-optical effect, making them promising for new applications in integrated multifunctional photonic circuits. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  14. Diversity-oriented peptide stapling

    DEFF Research Database (Denmark)

    Tran, Thu Phuong; Larsen, Christian Ørnbøl; Røndbjerg, Tobias

    2017-01-01

    The introduction of macrocyclic constraints in peptides (peptide stapling) is an important tool within peptide medicinal chemistry for stabilising and pre-organising peptides in a desired conformation. In recent years, the copper-catalysed azide-alkyne cycloaddition (CuAAC) has emerged as a power......The introduction of macrocyclic constraints in peptides (peptide stapling) is an important tool within peptide medicinal chemistry for stabilising and pre-organising peptides in a desired conformation. In recent years, the copper-catalysed azide-alkyne cycloaddition (CuAAC) has emerged...... incorporating two azide-modified amino acids with 1,3,5-triethynylbenzene efficiently provides (i, i+7)- and (i, i+9)-stapled peptides with a single free alkyne positioned on the staple, that can be further conjugated or dimerised. A unique feature of the present method is that it provides easy access...

  15. Dietary Sugars and Endogenous Formation of Advanced Glycation Endproducts: Emerging Mechanisms of Disease.

    Science.gov (United States)

    Aragno, Manuela; Mastrocola, Raffaella

    2017-04-14

    The rapid increase in metabolic diseases, which occurred in the last three decades in both industrialized and developing countries, has been related to the rise in sugar-added foods and sweetened beverages consumption. An emerging topic in the pathogenesis of metabolic diseases related to modern nutrition is the role of Advanced Glycation Endproducts (AGEs). AGEs can be ingested with high temperature processed foods, but also endogenously formed as a consequence of a high dietary sugar intake. Animal models of high sugar consumption, in particular fructose, have reported AGE accumulation in different tissues in association with peripheral insulin resistance and lipid metabolism alterations. The in vitro observation that fructose is one of the most rapid and effective glycating agents when compared to other sugars has prompted the investigation of the in vivo fructose-induced glycation. In particular, the widespread employment of fructose as sweetener has been ascribed by many experimental and observational studies for the enhancement of lipogenesis and intracellular lipid deposition. Indeed, diet-derived AGEs have been demonstrated to interfere with many cell functions such as lipid synthesis, inflammation, antioxidant defences, and mitochondrial metabolism. Moreover, emerging evidence also in humans suggest that this impact of dietary AGEs on different signalling pathways can contribute to the onset of organ damage in liver, skeletal and cardiac muscle, and the brain, affecting not only metabolic control, but global health. Indeed, the most recent reports on the effects of high sugar consumption and diet-derived AGEs on human health reviewed here suggest the need to limit the dietary sources of AGEs, including added sugars, to prevent the development of metabolic diseases and related comorbidities.

  16. Effects of photobleaching on selected advanced glycation end products in the human lens

    DEFF Research Database (Denmark)

    Holm, Thomas; Raghavan, Cibin T; Nahomi, Rooban

    2015-01-01

    BackgroundCataract is the leading cause of blindness, especially in the developing world. To ease access to treatment, we have proposed that cataract could be treated non-invasively by photobleaching of the chemically modified proteins responsible for cataract formation. The present study was aimed...... at examining the optical and biochemical effects of the proposed treatment.MethodsHuman donor lenses were photobleaced using a 445 nm cw laser. Lens optical quality was assessed before and after photobleaching by light transmission and scattering. The concentration of the advanced glycation end products (AGEs...

  17. The clinical relevance of assessing advanced glycation endproducts accumulation in diabetes

    Directory of Open Access Journals (Sweden)

    Hillebrands Jan-Luuk

    2008-10-01

    Full Text Available Abstract Cardiovascular disease is the major cause of morbidity and mortality associated with diabetes. There is increasing evidence that advanced glycation endproducts (AGEs play a pivotal role in atherosclerosis, in particular in diabetes. AGE accumulation is a measure of cumulative metabolic and oxidative stress, and may so represent the "metabolic memory". Furthermore, increased AGE accumulation is closely related to the development of cardiovascular complications in diabetes. This review article will focus on the clinical relevance of measuring AGE accumulation in diabetic patients by focusing on AGE formation, AGEs as predictors of long-term complications, and interventions against AGEs.

  18. Peptide Integrated Optics.

    Science.gov (United States)

    Handelman, Amir; Lapshina, Nadezda; Apter, Boris; Rosenman, Gil

    2018-02-01

    Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Characterizing harmful advanced glycation end-products (AGEs) and ribosylated aggregates of yellow mustard seed phytocystatin: Effects of different monosaccharides

    Science.gov (United States)

    Ahmed, Azaj; Shamsi, Anas; Bano, Bilqees

    2017-01-01

    Advanced glycation end products (AGEs) are at the core of variety of diseases ranging from diabetes to renal failure and hence gaining wide consideration. This study was aimed at characterizing the AGEs of phytocystatin isolated from mustard seeds (YMP) when incubated with different monosaccharides (glucose, ribose and mannose) using fluorescence, ultraviolet, circular dichroism (CD) spectroscopy and microscopy. Ribose was found to be the most potent glycating agent as evident by AGEs specific fluorescence and absorbance. YMP exists as a molten globule like structure on day 24 as depicted by high ANS fluorescence and altered intrinsic fluorescence. Glycated YMP as AGEs and ribose induced aggregates were observed at day 28 and 32 respectively. In our study we have also examined the anti-aggregative potential of polyphenol, resveratrol. Our results suggested the anti-aggregative behavior of resveratrol as it prevented the in vitro aggregation of YMP, although further studies are required to decode the mechanism by which resveratrol prevents the aggregation.

  20. Advanced glycation end-products (AGEs) and associations with cardio-metabolic, lifestyle, and dietary factors in a general population : The NQplus study

    NARCIS (Netherlands)

    Botros, Nadia; Sluik, Diewertje; van Waateringe, Robert P.; de Vries, Jeanne H. M.; Geelen, Anouk; Feskens, Edith J. M.

    Background: Advanced glycation end-products are a heterogeneous group of molecules that are formed during reactions between reducing sugars and proteins. Advanced glycation end-products are thought to play a role in several diseases, including diabetes mellitus and can be measured non-invasively

  1. Utility of glycated albumin for the diagnosis of diabetes mellitus in a Japanese population study: results from the Kyushu and Okinawa Populaiton Study (KOPS)

    Science.gov (United States)

    Glycated albumin is a measure of the mean plasma glucose concentration over approximately 2-3 weeks. We determined reference values for glycated albumin, and assessed its utility for the diagnosis of type 2 diabetes mellitus in the general population. We studied 1,575 men and women (mean age, 49.9 y...

  2. Synthetic antibiofilm peptides.

    Science.gov (United States)

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. The distribution of advanced glycation end products and their receptor in the gastrointestinal tract in the rats

    DEFF Research Database (Denmark)

    Chen, Pengmin; Zhao, Jingbo; Gregersen, Hans

    2012-01-01

    To investigate the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the gastrointestinal (GI) tract to provide a basis for further study of the association between AGE/RAGE and diabetic GI dysfunction. METHODS: The distribution of AGEs [N epsilon-(carboxymethyl)......To investigate the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the gastrointestinal (GI) tract to provide a basis for further study of the association between AGE/RAGE and diabetic GI dysfunction. METHODS: The distribution of AGEs [N epsilon...

  4. Therapeutic HIV Peptide Vaccine

    DEFF Research Database (Denmark)

    Fomsgaard, Anders

    2015-01-01

    Therapeutic vaccines aim to control chronic HIV infection and eliminate the need for lifelong antiretroviral therapy (ART). Therapeutic HIV vaccine is being pursued as part of a functional cure for HIV/AIDS. We have outlined a basic protocol for inducing new T cell immunity during chronic HIV-1...... infection directed to subdominant conserved HIV-1 epitopes restricted to frequent HLA supertypes. The rationale for selecting HIV peptides and adjuvants are provided. Peptide subunit vaccines are regarded as safe due to the simplicity, quality, purity, and low toxicity. The caveat is reduced immunogenicity...

  5. Peptide Vaccine Against Paracoccidioidomycosis.

    Science.gov (United States)

    Taborda, Carlos P; Travassos, Luiz R

    2017-01-01

    The chapter reviews methods utilized for the isolation and characterization of a promising immunogen candidate, aiming at a human vaccine against paracoccidioidomycosis. Peptide P10 carries a T-CD4+ epitope and was identified as an internal sequence of the major diagnostic antigen known as gp43 glycoprotein. It successfully treated massive intratracheal infections by virulent Paracoccidioides brasiliensis in combination with chemotherapy.An introduction about the systemic mycosis was found essential to understand the various options that were considered to design prophylactic and therapeutic vaccine protocols using peptide P10.

  6. Antioxidative capacity and binding affinity of the complex of green tea catechin and beta-lactoglobulin glycated by the Maillard reaction.

    Science.gov (United States)

    Perusko, Marija; Al-Hanish, Ayah; Mihailovic, Jelena; Minic, Simeon; Trifunovic, Sara; Prodic, Ivana; Cirkovic Velickovic, Tanja

    2017-10-01

    Major green tea catechin, epigallocatechin-3-gallate (EGCG), binds non-covalently to numerous dietary proteins, including beta-lactoglobulin of cow's milk. The effects of glycation of proteins via Maillard reaction on the binding capacity for polyphenols and the antiradical properties of the formed complexes have not been studied previously. Binding constant of BLG glycated by milk sugar lactose to EGCG was measured by the method of fluorophore quenching. Binding of EGCG was confirmed by CD and FTIR. The antioxidative properties of the complexes were examined by measuring ABTS radical scavenging capacity, superoxide anion scavenging capacity and total reducing power assay. Glycation of BLG does not significantly influence the binding constant of EGCG for the protein. Conformational changes were observed for both native and glycated BLG upon complexation with EGCG. Masking effect of polyphenol complexation on the antioxidative potential of the protein was of the similar degree for both glycated BLG and native BLG. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. 糖基化终末产物及其受体在糖尿病大鼠胃组织中的分布 (Distribution of advanced glycation end products and their receptor in the stomach of diabetic rats)

    DEFF Research Database (Denmark)

    Tian, Jia Xing; Zhao, Jingbo; Li, Min

    2015-01-01

    AIM: To observe the distribution of advanced glycation end products (AGEs) and their receptor (RAGE) in the stomach of diabetic rats. METHODS: Diabetes mellitus (DM) and control (CON) rats were reared for eight weeks. Fasting plasma glucose (FPG), glycated serum protein (GSP) and gastric layer...... end products; Receptor for advanced glycation end products...

  8. An advanced glycation endproduct (AGE)-rich diet promotes accumulation of AGEs in Achilles tendon

    DEFF Research Database (Denmark)

    Skovgaard, Dorthe; Svensson, Rene B; Scheijen, Jean

    2017-01-01

    Advanced Glycation Endproducts (AGEs) accumulate in long-lived tissue proteins like collagen in bone and tendon causing modification of the biomechanical properties. This has been hypothesized to raise the risk of orthopedic injury such as bone fractures and tendon ruptures. We evaluated the rela......Advanced Glycation Endproducts (AGEs) accumulate in long-lived tissue proteins like collagen in bone and tendon causing modification of the biomechanical properties. This has been hypothesized to raise the risk of orthopedic injury such as bone fractures and tendon ruptures. We evaluated...... the relationship between AGE content in the diet and accumulation of AGEs in weight-bearing animal Achilles tendon. Two groups of mice (C57BL/6Ntac) were fed with either high-fat diet low in AGEs high-fat diet (HFD) (n = 14) or normal diet high in AGEs (ND) (n = 11). AGE content in ND was six to 50-fold higher...... than HFD The mice were sacrificed at week 40 and Achilles and tail tendons were carefully excised to compare weight and nonweight-bearing tendons. The amount of the AGEs carboxymethyllysine (CML), methylglyoxal-derived hydroimidazolone (MG-H1) and carboxyethyllysine (CEL) in Achilles and tail tendon...

  9. Relationship between Glycation and Polyphenol Content and the Bioactivity of Selected Commercial Soy Milks.

    Science.gov (United States)

    Arques, M Carmen; Pastoriza, Silvia; Delgado-Andrade, Cristina; Clemente, Alfonso; Rufián-Henares, José A

    2016-03-02

    Soy milk is a health-promoting beverage of which consumption is steadily expanding. Different bioactivities have been associated with soy products such as antioxidant capacity, anti-inflammatory properties, or decrease of cancer development risk. These activities have been related to the presence of several compounds, including polyphenols and serine protease inhibitors, although factors influencing such activities have been scarcely studied. In this study, we have determined the antioxidant capacity (ABTS and FRAP methods measured with the global antioxidant response, GAR protocol), total phenolic content, serine protease inhibitory activity, and presence of heat damage indicators in commercial soy milks. Polyphenols were primarily responsible for the antioxidant capacity of soy milks, increasing their concentration after digestion. Glycation under heat treatment might be responsible for decreasing protease inhibitory activities in soy milks. The results obtained support a role for furosine, a known marker of Maillard reaction and glycation, as a potential indicator to monitor both thermal treatment and effects on protease inhibitory activities in soy milk. The contribution of soy milk consumption to the daily intake of antioxidants and serine protease inhibitory activities is discussed.

  10. Role of the receptor for advanced glycation end products in hepatic fibrosis.

    Science.gov (United States)

    Lohwasser, Christina; Neureiter, Daniel; Popov, Yury; Bauer, Michael; Schuppan, Detlef

    2009-12-14

    To study the role of advanced glycation end products (AGE) and their specific receptor (RAGE) in the pathogenesis of liver fibrogenesis. In vitro RAGE expression and extracellular matrix-related gene expression in both rat and human hepatic stellate cells (HSC) were measured after stimulation with the two RAGE ligands, advanced glycation end product-bovine serum albumin (AGE-BSA) and N(epsilon)-(carboxymethyl) lysine (CML)-BSA, or with tumor necrosis factor-alpha (TNF-alpha). In vivo RAGE expression was examined in models of hepatic fibrosis induced by bile duct ligation or thioacetamide. The effects of AGE-BSA and CML-BSA on HSC proliferation, signal transduction and profibrogenic gene expression were studied in vitro. In hepatic fibrosis, RAGE expression was enhanced in activated HSC, and also in endothelial cells, inflammatory cells and activated bile duct epithelia. HSC expressed RAGE which was upregulated after stimulation with AGE-BSA, CML-BSA, and TNF-alpha. RAGE stimulation with AGE-BSA and CML-BSA did not alter HSC proliferation, apoptosis, fibrogenic signal transduction and fibrosis- or fibrolysis-related gene expression, except for marginal upregulation of procollagen alpha1(I) mRNA by AGE-BSA. Despite upregulation of RAGE in activated HSC, RAGE stimulation by AGE does not alter their fibrogenic activation. Therefore, RAGE does not contribute directly to hepatic fibrogenesis.

  11. Ligand binding affinity and changes in the lateral diffusion of receptor for advanced glycation endproducts (RAGE).

    Science.gov (United States)

    Syed, Aleem; Zhu, Qiaochu; Smith, Emily A

    2016-12-01

    The effect of ligand on the lateral diffusion of receptor for advanced glycation endproducts (RAGE), a receptor involved in numerous pathological conditions, remains unknown. Single particle tracking experiments that use quantum dots specifically bound to hemagglutinin (HA)-tagged RAGE (HA-RAGE) are reported to elucidate the effect of ligand binding on HA-RAGE diffusion in GM07373 cell membranes. The ligand used in these studies is methylglyoxal modified-bovine serum albumin (MGO-BSA) containing advanced glycation end products modifications. The binding affinity between soluble RAGE and MGO-BSA increases by 1.8 to 9.7-fold as the percent primary amine modification increases from 24 to 74% and with increasing negative charge on the MGO-BSA. Ligand incubation affects the HA-RAGE diffusion coefficient, the radius of confinement, and duration of confinement. There is, however, no correlation between MGO-BSA ligand binding affinity with soluble RAGE and the extent of the changes in HA-RAGE lateral diffusion. The ligand induced changes to HA-RAGE lateral diffusion do not occur when cholesterol is depleted from the cell membrane, indicating the mechanism for ligand-induced changes to HA-RAGE diffusion is cholesterol dependent. The results presented here serve as a first step in unraveling how ligand influences RAGE lateral diffusion. Copyright © 2016. Published by Elsevier B.V.

  12. Screening system of blocking agents of the receptor for advanced glycation endproducts in cells using fluorescence.

    Science.gov (United States)

    Jung, Dong Ho; Kim, Young Sook; Kim, Jin Sook

    2012-01-01

    Activation of the receptor for advanced glycation endproducts (RAGE) triggers cellular responses implicated in the pathogenesis of diabetic complications; blockade of RAGE has been shown to inhibit the development of diabetic complications. To develop a screening system to identify novel disruptors of advanced glycation endproducts (AGE)-RAGE binding, we used an AGE-RAGE binding system in RAGE-overexpressing cells; test compounds were screened using this system. To construct human RAGE-overexpressing cells, mouse mesangial cells (MMCs) were stably transfected with the pcDNA-human RAGE (hRAGE) vector and selected under 1 mg/mL gentamicin (G418). RAGE expression in hRAGE-overexpressing MMCs was analyzed by Western blotting with specific RAGE antibody. To identify novel disruptors of AGE-RAGE binding, 50 single compounds and AGE-bovine serum albumin (BSA)-Alexa 488 (AGE-BSA labeled with Alexa 488) were treated to the hRAGE-overexpressing MMCs. Nonbinding AGE-BSA-Alexa 488 was washed and fluorescence measured by microtiter plate reader (excitation wavelength, 485 nm; emission wavelength, 528 nm). In hRAGE-overexpressing cells, only treatment with AGE-BSA-Alexa 488 significantly increased fluorescence intensity in a dose-dependent manner. Of 50 compounds tested, genistein disrupted AGE-RAGE binding in a dose-dependent manner. This AGE-RAGE binding system using AGE-BSA-Alexa 488 in hRAGE-overexpressing cells was suitable for screening of agents that disrupt AGE-hRAGE binding.

  13. Differential effects between amphoterin and advanced glycation end products on colon cancer cells.

    Science.gov (United States)

    Kuniyasu, Hiroki; Chihara, Yoshitomo; Kondo, Hideaki

    2003-05-10

    Amphoterin is 1 ligand of the receptor for advanced glycation end products (RAGE). We studied expression of amphoterin and RAGE mRNA and proteins in colorectal carcinoma cells and investigated their associations with the invasive activities of cells exposed to advanced glycation end products (AGE). Expression of RAGE and amphoterin was examined in 4 colorectal carcinoma cell lines. All cell lines expressed both RAGE and amphoterin. The effects of RAGE and amphoterin on cell growth (MTT assay), migration (wound healing assay) and invasion (in vitro invasion assay) were tested by treatment of cells with RAGE and amphoterin antisense S-oligodeoxynucleotides (ODNs). Cell growth, migration and invasion were inhibited significantly in Colo320 and WiDr carcinoma cells treated with RAGE and amphoterin antisense S-ODNs compared with sense-treated cells. Differences in ligand activity between amphoterin and AGE were examined with AGE-bovine serum albumin (BSA). AGE-BSA decreased cell growth, migration and invasion of amphoterin antisense S-ODN-treated Colo320 and WiDr cells compared with those of cells treated with Colo320 conditioned medium. Phosphorylation of extracellular signal-regulated kinase-1/2, Rac1 and AKT and production of matrix metalloproteinase 9 were increased to a greater degree by amphoterin than by AGE-BSA. In contrast, production of inducible nitric oxide synthase and nuclear factor-kappaBp65 were increased to a greater degree by AGE-BSA than by amphoterin. Copyright 2003 Wiley-Liss, Inc.

  14. Estimating average glucose levels from glycated albumin in patients with end-stage renal disease.

    Science.gov (United States)

    Kim, Jwa-Kyung; Park, Jung Tak; Oh, Hyung Jung; Yoo, Dong Eun; Kim, Seung Jun; Han, Seung Hyeok; Kang, Shin-Wook; Choi, Kyu Hun; Yoo, Tae-Hyun

    2012-05-01

    In patients with diabetic end stage renal disease (ESRD), glycated albumin (GA) reflects recent glycemic control more accurately than glycated hemoglobin (HbA1c). We evaluated the relationship between GA and average blood glucose (AG) level and developed an estimating equation for translating GA values into easier-to-understand AG levels. A total of 185 ESRD patients, including 154 diabetic and 31 non-diabetic participants, were enrolled (108 hemodialysis, 77 peritoneal dialysis). Patients were asked to perform four-point daily self-monitoring of capillary blood glucose (SMBG) at least three consecutive days each week for four weeks. Serum levels of GA, HbA1c and other biochemical parameters were checked at baseline, as well as at 4 and 8 weeks. Approximately 74.3±7.0 SMBG readings were obtained from each participant and mean AG was 169.1±48.2 mg/dL. The correlation coefficient between serum GA and AG levels (r=0.70, paverage blood glucose level of 155-160 mg/dL could be matched to a GA value of 18-19% in patients with ESRD.

  15. Protein glycation and aggregation inhibitory potency of biomolecules from black gram milled by-product.

    Science.gov (United States)

    Girish, Talakatta K; Prasada Rao, Ummiti Js

    2016-12-01

    Persistent hyperglycaemia causes increased advanced glycation end products (AGEs), which contribute to the pathogenesis of diabetic complication. Therefore, effect of black gram milled by-product (BGBP) extract on inhibition of AGE formation in a bovine serum albumin (BSA)/glucose system was investigated. BGBP extract had a total polyphenol content of 82 mg GAE g -1 and flavonoid content of 46 mg CE g -1 . Ferulic acid, protocatechuic acid, gallic acid, gentisic acid, isovitexin, vitexin and epicatechin were the major bioactives in the extract. BGBP extract exhibited an effective Fe 2+ chelating activity. Size exclusion-high-performance liquid chromatographic studies indicated that upon BSA-AGE formation the BSA monomer content was 38%; however, in the presence of BGBP extract at 50 and 100 µg levels, the monomer content increased and it was found to be 48% and 73%, respectively. BGBP extract at 50 and 100 µg levels decreased the protein carbonyl and fructosamine contents, and quenched the fluorescence intensity of glycated BSA in a dose-dependent manner. Further, fluorescence and transmission electron microscopic studies confirmed the decrease in formation of AGEs by BGBP extract. As BGBP extract inhibited the formation of AGEs, the extract can be used as a nutraceutical or it can be incorporated into food products to obtain functional foods. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  16. Antioxidant, Anti-Glycation and Anti-Inflammatory Activities of Phenolic Constituents from Cordia sinensis

    Directory of Open Access Journals (Sweden)

    Muhammad Nasir

    2011-12-01

    Full Text Available Nine compounds have been isolated from the ethyl acetate soluble fraction of C. sinensis, namely protocatechuic acid (1, trans-caffeic acid (2, methyl rosmarinate (3, rosmarinic acid (4, kaempferide-3-O-β-D-glucopyranoside (5, kaempferol-3-O-β-D-glucopyranoside (6, quercetin-3-O-β-D-glucopyranoside (7, kaempferide-3-O-α-L-rhamnopyranosyl (1→6-β-D-glucopyranoside (8 and kaempferol-3-O-α-L-rhamno-pyranosyl (1→6-β-D-glucopyranoside (9, all reported for the first time from this species. The structures of these compounds were deduced on the basis of spectroscopic studies, including 1D and 2D NMR techniques. Compounds 1–9 were investigated for biological activity and showed significant anti-inflammatory activity in the carrageen induced rat paw edema test. The antioxidant activities of isolated compounds 1–9 were evaluated by the DPPH radical scavenging test, and compounds 1, 2, 4 and 7–9 exhibited marked scavenging activity compared to the standard BHA. These compounds were further studied for their anti-glycation properties and some compounds showed significant anti-glycation inhibitory activity. The purity of compounds 2–5, 8 and 9 was confirmed by HPLC. The implications of these results for the chemotaxonomic studies of the genus Cordia have also been discussed.

  17. Definition of the upper reference limit of glycated albumin in blood donors from Italy.

    Science.gov (United States)

    Bellia, Chiara; Zaninotto, Martina; Cosma, Chiara; Agnello, Luisa; Lo Sasso, Bruna; Bivona, Giulia; Plebani, Mario; Ciaccio, Marcello

    2017-11-27

    Glycated Albumin (GA) has been proposed as a short-term indicator of glycemic homeostasis. The aim of this study is to describe the distribution of GA in a large sample of blood donors from Italy to evaluate whether demographic features, namely age and sex, could influence GA levels and define specific reference limits. The study included 1334 Italian blood donors. GA was measured using an enzymatic method (quantILab Glycated Albumin, IL Werfen, Germany). The upper reference limit (URL) was calculated using the non-parametric percentile method. A modest, although significant, increase of GA was observed in relation to age (psex (12% [11.3-12.8] in males; 12.2% [11.4-13.1] in females; p=0.01). After excluding individuals with fasting plasma glucose ≥7 mmol/L, the calculated GA URL was 14.5% (95% CI: 14.3-14.7). Subjects with GA>14.5% presented a mean age of 48.4±12.2 years, 66.7% were males and the mean glucose was 6.88±2.5 mmol/L. GA in Caucasians shows a similar increasing trend at older ages documented in other ethnicities. The definition of the URL in this population could be useful for both clinical studies, which will clarify the role of GA for diagnosing and monitoring diabetes, and will encourage the introduction of GA in clinical practice.

  18. Natural antioxidant polyphenols on inflammation management: Anti-glycation activity vs metalloproteinases inhibition.

    Science.gov (United States)

    Crascì, Lucia; Lauro, Maria Rosaria; Puglisi, Giovanni; Panico, Annamaria

    2016-09-20

    The diet polyphenols are a secondary metabolites of plants able to act on inflammation process. Their anti-inflammatory activity is articulated through several mechanisms that are related to their antioxidative and radical scavengers properties. Our work is focused on a novel approach to inflammatory disease management, based on anti-glycative and matrix metalloproteinases (MMPs) inhibition effects, as a connected phenomena. To better understand these correlation, polyphenols Structure-Activity Relationship (SAR) studies were also reported. The antioxidant polyphenols inhibit the AGEs at different levels of the glycation process in the following ways: (1) prevention of Amadori adduct oxidation; (2) trapping reactive dycarbonyl compounds; (3) attenuation of receptor for AGEs (RAGE) expression. Moreover, several flavonoids with radical scavenging property showed also MMPs inhibition interact directly with MMPs or indirectly via radical scavengers and AGEs reduction. The essential polyphenols features involved in these mechanisms are C2-C3 double bond and number and position of hydroxyl, glycosyl and O-methyl groups. These factors induce a change in molecular planarity interfering with the hydrogen bond formation, electron delocalization and metal ion chelation. In particular, C2-C3 double bond improve the antioxidant and MMPs inhibition, while the hydroxylation, glycosylation and methylation induce a positive and negative correlation, respectively.

  19. Soft-tissue wound healing by anti-advanced glycation end-products agents.

    Science.gov (United States)

    Chang, P-C; Tsai, S-C; Jheng, Y-H; Lin, Y-F; Chen, C-C

    2014-04-01

    The blocking of advanced glycation end-products (AGE) has been shown to reduce diabetic complications and control periodontitis. This study investigated the pattern of palatal wound-healing after graft harvesting under the administration of aminoguanidine (AG), an AGE inhibitor, or N-phenacylthiazolium bromide (PTB), a glycated cross-link breaker. Full-thickness palatal excisional wounds (5.0 x 1.5 mm(2)) were created in 72 Sprague-Dawley rats. The rats received daily intraperitoneal injections of normal saline (control), AG, or PTB and were euthanized after 4 to 28 days. The wound-healing pattern was assessed by histology, histochemistry for collagen matrix deposition, immunohistochemistry for AGE and the AGE receptor (RAGE), and the expression of RAGE, as well as inflammation- and recovery-associated genes. In the first 14 days following AG or PTB treatments, wound closure, re-epithelialization, and collagen matrix deposition were accelerated, whereas AGE deposition, RAGE-positive cells, and inflammation were reduced. RAGE and tumor necrosis factor-alpha were significantly down-regulated at day 7, and heme oxygenase-1 was persistently down-regulated until day 14. The levels of vascular endothelial growth factor, periostin, type I collagen, and fibronectin were all increased at day 14. In conclusion, anti-AGE agents appeared to facilitate palatal wound-healing by reducing AGE-associated inflammation and promoting the recovery process.

  20. Effect of taurine on advanced glycation end products-induced hypertrophy in renal tubular epithelial cells

    International Nuclear Information System (INIS)

    Huang, J.-S.; Chuang, L.-Y.; Guh, J.-Y.; Yang, Y.-L.; Hsu, M.-S.

    2008-01-01

    Mounting evidence indicates that advanced glycation end products (AGE) play a major role in the development of diabetic nephropathy (DN). Taurine is a well documented antioxidant agent. To explore whether taurine was linked to altered AGE-mediated renal tubulointerstitial fibrosis in DN, we examined the molecular mechanisms of taurine responsible for inhibition of AGE-induced hypertrophy in renal tubular epithelial cells. We found that AGE (but not non-glycated BSA) caused inhibition of cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, bcl-2 protein expression, and mitochondrial cytochrome c release in BSA, AGE, or the antioxidant taurine treatments in these cells. AGE-induced the Raf-1/extracellular signal-regulated kinase (ERK) activation was markedly blocked by taurine. Furthermore, taurine, the Raf-1 kinase inhibitor GW5074, and the ERK kinase inhibitor PD98059 may have the ability to induce cellular proliferation and cell cycle progression from AGE-treated cells. The ability of taurine, GW5074, or PD98059 to inhibit AGE-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of RAGE, p27 Kip1 , collagen IV, and fibronectin. The results obtained in this study suggest that taurine may serve as the potential anti-fibrotic activity in DN through mechanism dependent of its Raf-1/ERK inactivation in AGE-induced hypertrophy in renal tubular epithelial cells

  1. Serum glycated albumin predicts the progression of diabetic retinopathy--a five year retrospective longitudinal study.

    Science.gov (United States)

    Pan, Jiemin; Li, Qing; Zhang, Lei; Jia, Lili; Tang, Junling; Bao, Yuqian; Jia, Weiping

    2014-01-01

    To assess the predictive value of glycated albumin (GA) and other risk factors on a progression of diabetic retinopathy (DR). In this retrospective longitudinal study, we enrolled the subjects with type 2 diabetes who had undergone fundus photography twice with a 5-years gap between January 2006 and December 2012, and had been measured consecutively for hemoglobin A1c (HbA1c) and GA levels every 3 or 6 months. The subjects were divided into two groups with or without a progression of DR. The mean HbA1c and mean GA were calculated separately by the sum of all measured values divided by the numbers of values throughout the study period. Of the 359 subjects, progression group showed significantly higher diabetes duration (8.41±5.72 vs. 6.46±5.77, Ppredict DR progression were 7.27% and 21.85%, respectively. The presence of DR at baseline, poor glycemic control, glycated albumin, and impaired renal function predicted DR progression in patients with type 2 diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Ameliorating Effect of Akebia quinata Fruit Extracts on Skin Aging Induced by Advanced Glycation End Products

    Directory of Open Access Journals (Sweden)

    Seoungwoo Shin

    2015-11-01

    Full Text Available The accumulation of free radicals and advanced glycation end products (AGEs in the skin plays a very important role in skin aging. Both are known to interact with each other. Therefore, natural compounds or extracts that possess both antioxidant and antiglycation activities might have great antiageing potential. Akebia quinata fruit extract (AQFE has been used to treat urinary tract inflammatory disease in traditional Korean and Chinese medicines. In the present study, AQFE was demonstrated to possess antioxidant and antiglycation activity. AQFE protects human dermal fibroblasts (HDFs from oxidative stress and inhibits cellular senescence induced by oxidative stress. We also found that AQFE inhibits glycation reaction between BSA and glucose. The antiglycation activity of AQFE was dose-dependent. In addition, the antiglycation activity of AQFE was confirmed in a human skin explant model. AQFE reduced CML expression and stimulated fibrillin-1 expression in comparison to the methyglyoxal treatment. In addition, the possibility of the extract as an anti-skin aging agent has also been clinically validated. Our analysis of the crow’s feet wrinkle showed that there was a decrease in the depth of deep furrows in RI treated with AQFE cream over an eight-week period. The overall results suggest that AQFE may work as an anti-skin aging agent by preventing oxidative stress and other complications associated with AGEs formation.

  3. N-phenacylthiazolium bromide reduces bone fragility induced by nonenzymatic glycation.

    Directory of Open Access Journals (Sweden)

    Brian S Bradke

    Full Text Available Nonenzymatic glycation (NEG describes a series of post-translational modifications in the collagenous matrices of human tissues. These modifications, known as advanced glycation end-products (AGEs, result in an altered collagen crosslink profile which impacts the mechanical behavior of their constituent tissues. Bone, which has an organic phase consisting primarily of type I collagen, is significantly affected by NEG. Through constant remodeling by chemical resorption, deposition and mineralization, healthy bone naturally eliminates these impurities. Because bone remodeling slows with age, AGEs accumulate at a greater rate. An inverse correlation between AGE content and material-level properties, particularly in the post-yield region of deformation, has been observed and verified. Interested in reversing the negative effects of NEG, here we evaluate the ability of n-phenacylthiazolium bromide (PTB to cleave AGE crosslinks in human cancellous bone. Cancellous bone cylinders were obtained from nine male donors, ages nineteen to eighty, and subjected to one of six PTB treatments. Following treatment, each specimen was mechanically tested under physiological conditions to failure and AGEs were quantified by fluorescence. Treatment with PTB showed a significant decrease in AGE content versus control NEG groups as well as a significant rebound in the post-yield material level properties (p<0.05. The data suggest that treatment with PTB could be an effective means to reduce AGE content and decrease bone fragility caused by NEG in human bone.

  4. Short-term effects of dietary advanced glycation end products in rats

    DEFF Research Database (Denmark)

    Poulsen, Malene Wibe; Andersen, Jeanette Marker; Hedegaard, Rikke Susanne Vingborg

    2016-01-01

    Dietary advanced glycation end products (AGE) formed during heating of food have gained interest as potential nutritional toxins with adverse effects on inflammation and glucose metabolism. In the present study, we investigated the short-term effects of high and low molecular weight (HMW and LMW)...... the groups. In conclusion, RAGE and AGER1 expression can be influenced by a high AGE diet after only 2 weeks in proportion to MG-H1 excretion. No other short-term effects were observed.......Dietary advanced glycation end products (AGE) formed during heating of food have gained interest as potential nutritional toxins with adverse effects on inflammation and glucose metabolism. In the present study, we investigated the short-term effects of high and low molecular weight (HMW and LMW......) dietary AGE on insulin sensitivity, expression of the receptor for AGE (RAGE), the AGE receptor 1 (AGER1) and TNF-α, F2-isoprostaglandins, body composition and food intake. For 2 weeks, thirty-six Sprague-Dawley rats were fed a diet containing 20 % milk powder with different proportions of this being...

  5. Optimizing Carnosine Containing Extract Preparation from Chicken Breast for Anti-glycating agents.

    Science.gov (United States)

    Kim, Seung-Ki; Kwon, Dodan; Kwon, Da-Ae; Paik, In Kee; Auh, Joong-Hyuck

    2014-01-01

    Optimization of carnosine and anserine extraction from chicken breast was performed using response surface methodology (RSM) to obtain the maximized physiological activities for anti-glycation and anti-oxidation. The optimum extraction conditions were water extraction for 1.6 h in the case of the 20-wk laying hen muscle and water extraction for 2.12 h in the case of 90-wk laying hen muscle. Higher carnosine and anserine contents were measured in the 20-wk laying hen muscle, along with higher physiological activities, which increased in direct proportion with the dipeptide contents. The extracts prepared from the 20-wk laying hen under optimum conditions showed 57% inhibition of advanced glycated end-product formation, 64% inhibition of lipid peroxidation, and 61% of DPPH radical scavenging effects. On the other hand, 52% inhibition of AGE formation, 62% inhibition of lipid peroxidation, and 53% of DPPH radical scavenging effect were demonstrated within the 90-wk laying hen. In addition, the ratio of carnosine was a key indicator for the physiological activities of the extracts.

  6. Plasma Ascorbic Acid and Non-Enzymatic Antioxidants Level in ...

    African Journals Online (AJOL)

    Free radicals have been implicated in the pathology of several diseases including cataract. Ascorbic acid functions as the major chain breaking antioxidant vitamin in the aqueous phase. Bilirubin, albumin and uric acid are regarded as natural antioxidants. There are conflicting reports on plasma concentrations of these ...

  7. Non-Enzymatic Oligomerization of 3 ', 5 ' Cyclic AMP

    Czech Academy of Sciences Publication Activity Database

    Costanzo, G.; Pino, S.; Timperio, A.M.; Šponer, Judit E.; Sponer, Jiri; Nováková, Olga; Šedo, O.; Zdráhal, Z.; Di Mauro, E.

    2016-01-01

    Roč. 11, č. 11 (2016), č. článku e0165723. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA14-12010S; GA ČR GBP206/12/G151 Institutional support: RVO:68081707 Keywords : template-directed synthesis * nucleoside phosphorylation * montmorillonite catalysis * molecular-structure Subject RIV: BO - Biophysics Impact factor: 2.806, year: 2016

  8. Non-enzymatic palladium recovery on microbial and synthetic surfaces

    DEFF Research Database (Denmark)

    Rotaru, Amelia-Elena; Jiang, Wei; Finster, Kai

    2012-01-01

    The use of microorganisms as support for reduction of dissolved Pd(II) to immobilized Pd(0) nanoparticles is an environmentally friendly approach for Pd recovery from waste. To better understand and engineer Pd(0) nanoparticle synthesis, one has to consider the mechanisms by which Pd(II) is reduced...

  9. Comparative LC-MS/MS profiling of free and protein-bound early and advanced glycation-induced lysine modifications in dairy products.

    Science.gov (United States)

    Hegele, Jörg; Buetler, Timo; Delatour, Thierry

    2008-06-09

    Free and protein-bound forms of early and advanced glycation-induced lysine (Lys) modifications were quantified in dairy products by LC-MS/MS using a stable isotope dilution assay. The glycation profiles for N(epsilon)-fructoselysine (FL), N(epsilon)-carboxymethyllysine (CML) and pyrraline (Pyr) were monitored in raw and processed cow milk to investigate whether free glycation products could serve as fast and simple markers to assess the extent of protein glycation in dairy products. In all milk samples, the fraction of free glycation adducts was predominantly composed of advanced modifications, e.g. 8.34+/-3.81 nmol CML per micromol of free Lys (Lys(free)) and 81.5+/-87.8 nmol Pyr micromol(-1) Lys(free)(-1) vs. 3.72+/-1.29 nmol FL micromol(-1) Lys(free)(-1). In contrast, the protein-bound early glycation product FL considerably outweighed the content of CML and Pyr in milk proteins of raw and processed cow milk, whereas severely heat treated milk products, e.g. condensed milk, contained a higher amount of protein-bound advanced glycation adducts. Typical values recorded for milk samples processed under mild conditions were 0.47+/-0.08 nmol FL micromol(-1) of protein-bound Lys (Lys(p-b)), 0.04+/-0.03 nmol CML micromol(-1) Lys(p-b)(-1) and 0.06+/-0.02 nmol Pyr micromol(-1)Lys(p-b)(-1). It was particularly noticeable, however, that mild heat treatment of raw milk, i.e. pasteurization and UHT treatment, did not significantly increase the amount of both free and protein-bound Lys modifications. In conclusion, the profiles of free and protein-bound glycation-induced Lys modifications were found to be different and a screening of free glycation adducts does, therefore, not allow for a conclusion about the protein glycation status of dairy products.

  10. NCAM Mimetic Peptides: An Update

    DEFF Research Database (Denmark)

    Berezin, Vladimir; Bock, Elisabeth

    2008-01-01

    of combinatorial peptide libraries. The C3 and NBP10 peptides target the first Ig module whereas the ENFIN2 and ENFIN11 peptides target fibronectin type III (FN3) modules of NCAM. A number of NCAM mimetics can induce neurite outgrowth and exhibit neuroprotective and synaptic plasticity modulating properties...

  11. brain natriuretic peptide

    African Journals Online (AJOL)

    Background: Recently brain natriuretic peptide (BNP) level has been introduced as a screening test for congestive heart failure (CHF) in children. The current CHF assessment scores are not satisfactory as they use a large number of variables. Objective: To evaluate two CHF scores: a modified clinical score and an echo-.

  12. Brain Peptides and Psychopharmacology

    Science.gov (United States)

    Arehart-Treichel, Joan

    1976-01-01

    Proteins isolated from the brain and used as drugs can improve and apparently even transfer mental states and behavior. Much of the pioneering work and recent research with humans and animals is reviewed and crucial questions that are being posed about the psychologically active peptides are related. (BT)

  13. Generation of Soluble Advanced Glycation End Products Receptor (sRAGE)-Binding Ligands during Extensive Heat Treatment of Whey Protein/Lactose Mixtures Is Dependent on Glycation and Aggregation

    NARCIS (Netherlands)

    Liu, Fahui; Teodorowicz, Gosia; Wichers, Harry J.; Boekel, van Tiny; Hettinga, Kasper A.

    2016-01-01

    Heating of protein- and sugar-containing materials is considered the primary factor affecting the formation of advanced glycation end products (AGEs). This study aimed to investigate the influence of heating conditions, digestion, and aggregation on the binding capacity of AGEs to the soluble AGE

  14. [Biosynthesis of opioid peptides].

    Science.gov (United States)

    Rossier, J

    1988-01-01

    The endogenous opioid peptides all contain the enkephalin sequence Tyr-Gly-Gly-Phe-Met and Tyr-Gly-Gly-Phe-Leu at their aminoterminus. Three distinct families of these peptides (endorphins, enkephalins and dynorphins) are present in different neuronal pathways within the central nervous system. Molecular genetics have shown that these three families of opioid peptides are derived from three distinct precursors. Pro-opiomelanocortin gives rise to the endorphins, as well as adrenocorticotropic hormone (ACTH) and the melanotropic hormones (MSH's). [Met] enkephalin, [Leu] enkephalin and the related heptapeptide [Met] enkephalin-Arg6-Phe7 and octapeptide [Met] enkephalin-Arg6-Gly7-Leu8 are derived from proenkephalin. The third family is derived from prodynorphin and includes dynorphin A, dynorphin B (also known as rimorphin) and alpha- and beta-neo-endorphin. The structure of the genes coding for these precursors are similar, suggesting the possibility of one common ancestral gene. The most common scheme for enzymatic maturation of precursors proposes the action of a trypsin-like endopeptidase followed by a carboxypeptidase B-like exopeptidase. However, we have provided evidence that this combination of trypsin-like and carboxypeptidase B-like enzymes may not be the only mechanism for liberating enkephalin from low molecular weight enkephalin-containing peptides. Indeed, endo-oligopeptidase A, an enzyme, known to hydrolyze the Phe5-Ser6 bond of bradykinin and the Arg8-Arg9 bond of neurotensin, has been shown to produce, by a single cleavage, [Leu] enkephalin or [Met] enkephalin from small enkephalin-containing peptides, (Camargo et al., 1987, J. Neurochem. 48, 1258-1263).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Biochemical functionalization of peptide nanotubes with phage displayed peptides

    Science.gov (United States)

    Swaminathan, Swathi; Cui, Yue

    2016-09-01

    The development of a general approach for the biochemical functionalization of peptide nanotubes (PNTs) could open up existing opportunities in both fundamental studies as well as a variety of applications. PNTs are spontaneously assembled organic nanostructures made from peptides. Phage display has emerged as a powerful approach for identifying selective peptide binding motifs. Here, we demonstrate for the first time the biochemical functionalization of PNTs via peptides identified from a phage display peptide library. The phage-displayed peptides are shown to recognize PNTs. These advances further allow for the development of bifunctional peptides for the capture of bacteria and the self-assembly of silver particles onto PNTs. We anticipate that these results could provide significant opportunities for using PNTs in both fundamental studies and practical applications, including sensors and biosensors nanoelectronics, energy storage devices, drug delivery, and tissue engineering.

  16. Studies on the role of insect hemolymph polypeptides: Galleria mellonella anionic peptide 2 and lysozyme.

    Science.gov (United States)

    Sowa-Jasiłek, Aneta; Zdybicka-Barabas, Agnieszka; Stączek, Sylwia; Wydrych, Jerzy; Mak, Paweł; Jakubowicz, Teresa; Cytryńska, Małgorzata

    2014-03-01

    The lysozymes are well known antimicrobial polypeptides exhibiting antibacterial and antifungal activities. Their antibacterial potential is related to muramidase activity and non-enzymatic activity resembling the mode of action of cationic defense peptides. However, the mechanisms responsible for fungistatic and/or fungicidal activity of lysozyme are still not clear. In the present study, the anti-Candida albicans activity of Galleria mellonella lysozyme and anionic peptide 2 (AP2), defense factors constitutively present in the hemolymph, was examined. The lysozyme inhibited C. albicans growth in a dose-dependent manner. The decrease in the C. albicans survival rate caused by the lysozyme was accompanied by a considerable reduction of the fungus metabolic activity, as revealed by LIVE/DEAD staining. In contrast, although AP2 reduced C. albicans metabolic activity, it did not influence its survival rate. Our results suggest fungicidal action of G. mellonella lysozyme and fungistatic activity of AP2 toward C. albicans cells. In the presence of AP2, the anti-C. albicans activity of G. mellonella lysozyme increased. Moreover, when the fungus was incubated with both defense factors, true hyphae were observed besides pseudohyphae and yeast-like C. albicans cells. Atomic force microscopy analysis of the cells exposed to the lysozyme and/or AP2 revealed alterations in the cell surface topography and properties in comparison with the control cells. The results indicate synergistic action of G. mellonella AP2 and lysozyme toward C. albicans. The presence of both factors in the hemolymph of naive larvae suggests their important role in the early stages of immune response against fungi in G. mellonella. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Accumulation of Advanced Glycation End Products as a Molecular Mechanism for Aging as a Risk Factor in Osteoarthritis

    NARCIS (Netherlands)

    Groot, J. de; Verzijl, N.; Wenting-Wijk, M.J.G. van; Jacobs, K.M.G.; El, B. van; Roermund, P.M. van; Bank, R.A.; Bijlsma, J.W.J.; TeKoppele, J.M.; Lafeber, F.P.J.G.

    2004-01-01

    Objective. Osteoarthritis (OA) is one of the most prevalent and disabling chronic conditions affecting the elderly. Its etiology is largely unknown, but age is the most prominent risk factor. The current study was designed to test whether accumulation of advanced glycation end products (AGEs), which

  18. Association of Polymorphism in the Receptor for Advanced Glycation End Products (RAGE) Gene with Circulating RAGE Levels

    NARCIS (Netherlands)

    Gaens, Katrien H. J.; Ferreira, Isabel; van der Kallen, Carla J. H.; van Greevenbroek, Marleen M. J.; Blaak, Ellen E.; Feskens, Edith J. M.; Dekker, Jacqueline M.; Nijpels, Giel; Heine, Robert J.; 't Hart, Leen M.; de Groot, Philip G.; Stehouwer, Coen D. A.; Schalkwijk, Casper G.

    2009-01-01

    Objective: The receptor for advanced glycation end products (RAGE)-ligand interaction has been linked to vascular complications. The family of soluble forms of RAGE (sRAGE) consists of splice variants and proteolytically cleaved and shed forms of RAGE. sRAGE may be a reflection of cell-bound RAGE.

  19. Effect of Heating and Glycation on the Allergenicity of 2S Albumins (Ara h 2/6) from Peanut

    NARCIS (Netherlands)

    Vissers, Y.M.; Blanc, F.; Stahl Skov, P.; Johnson, P.E.; Rigby, N.M.; Przybylski-Nicaise, L.; Bernhard, H.; Wal, J.M.; Ballmer-Weber, B.; Zuidmeer-Jongejan, L.; Szepfalusi, Z.; Ruinemans-Koerts, J.; Jansen, A.P.H.; Savelkoul, H.F.J.; Wichers, H.J.; Mackie, A.R.; Mills, E.N.C.; Adel-Patient, K.

    2011-01-01

    Background Peanut allergy is one of the most common and severe food allergies, and processing is known to influence the allergenicity of peanut proteins. We aimed to establish the effect of heating and glycation on the IgE-binding properties and biological activity of 2S albumins (Ara h 2/6) from

  20. Effect of heating and glycation on the allergenicity of 2S albumins (Ara h 2/6) from peanut

    NARCIS (Netherlands)

    Vissers, Yvonne M.; Blanc, Fany; Skov, Per Stahl; Johnson, Phil E.; Rigby, Neil M.; Przybylski-Nicaise, Laetitia; Bernard, Hervé; Wal, Jean-Michel; Ballmer-Weber, Barbara; Zuidmeer-Jongejan, Laurian; Szépfalusi, Zsolt; Ruinemans-Koerts, Janneke; Jansen, Ad P. H.; Savelkoul, Huub F. J.; Wichers, Harry J.; Mackie, Alan R.; Mills, Clare E. N.; Adel-Patient, Karine

    2011-01-01

    Peanut allergy is one of the most common and severe food allergies, and processing is known to influence the allergenicity of peanut proteins. We aimed to establish the effect of heating and glycation on the IgE-binding properties and biological activity of 2S albumins (Ara h 2/6) from peanut.

  1. New Locus for Skin Intrinsic Fluorescence in Type 1 Diabetes Also Associated With Blood and Skin Glycated Proteins

    NARCIS (Netherlands)

    Roshandel, Delnaz; Klein, Ronald; Klein, Barbara E. K.; Wolffenbuttel, Bruce H. R.; van der Klauw, Melanie M.; van Vliet-Ostaptchouk, Jana V.; Atzmon, Gil; Ben-Avraham, Danny; Crandall, Jill P.; Barzilai, Nir; Bull, Shelley B.; Canty, Angelo J.; Hosseini, S. Mohsen; Hiraki, Linda T.; Maynard, John; Sell, David R.; Monnier, Vincent M.; Cleary, Patricia A.; Braffett, Barbara H.; Paterson, Andrew D.

    Skin fluorescence (SF) noninvasively measures advanced glycation end products (AGEs) in the skin and is a risk indicator for diabetes complications. N-acetyltransferase 2 (NAT2) is the only known locus influencing SF. We aimed to identify additional genetic loci influencing SF in type 1 diabetes

  2. Skin autofluorescence as a measure of advanced glycation endproduct deposition : a novel risk marker in chronic kidney disease

    NARCIS (Netherlands)

    Smit, Andries J.; Gerrits, Esther G.

    2010-01-01

    Purpose of review Skin autofluorescence (SAF) is a new method to noninvasively assess accumulation of advanced glycation endproducts (AGEs) in a tissue with low turnover. Recent progress in the clinical application of SAF as a risk marker for diabetic nephropathy as well as cardiovascular disease in

  3. Receptor for Advanced Glycation End Products Facilitates Host Defense during Escherichia coli-Induced Abdominal Sepsis in Mice

    NARCIS (Netherlands)

    van Zoelen, Marieke A. D.; Schmidt, Ann-Marie; Florquin, Sandrine; Meijers, Joost C.; de Beer, Regina; de Vos, Alex F.; Nawroth, Peter P.; Bierhaus, Angelika; van der Poll, Tom

    2009-01-01

    Background. The receptor for advanced glycation end products (RAGE) mediates a variety of inflammatory responses. Methods. To determine the role of RAGE in the innate immune response to abdominal sepsis caused by Escherichia coli, RAGE-deficient (RAGE(-/-)) and normal wild-type mice were

  4. Advanced glycation end products, measured in skin, vs. HbA1c in children with type 1 diabetes mellitus

    NARCIS (Netherlands)

    Banser, Alena; Naafs, Jolanda C.; Hoorweg-Nijman, Jantine J. G.; van de Garde, Ewoudt M. W.; van der Vorst, Marja M. J.

    2016-01-01

    Background and objectiveAdvanced glycation end products (AGEs) are considered major contributors to microvascular and macrovascular complications in adult patients with diabetes mellitus. AGEs can be measured non-invasively with skin autofluorescence (sAF). The primary aim was to determine sAF

  5. Selective label-free electrochemical impedance measurement of glycated haemoglobin on 3-aminophenylboronic acid-modified eggshell membranes

    DEFF Research Database (Denmark)

    Boonyasit, Yuwadee; Heiskanen, Arto; Chailapakul, Orawan

    2015-01-01

    We propose a novel alternative approach to long-term glycaemic monitoring using eggshell membranes (ESMs) as a new immobilising platform for the selective label-free electrochemical sensing of glycated haemoglobin (HbA1c), a vital clinical index of the glycaemic status in diabetic individuals. Due...

  6. The influence of body mass index on the accumulation of advanced glycation end products in hemodialysis patients

    NARCIS (Netherlands)

    Arsov, S.; Trajceska, L.; van Oeveren, W.; Smit, A. J.; Dzekova, P.; Stegmayr, B.; Sikole, A.; Rakhorst, G.; Graaff, R.

    BACKGROUND/OBJECTIVES: The level of skin autofluorescence (AF) at a given moment is an independent predictor of mortality in hemodialysis (HD) patients. Skin AF is a measure of the accumulation of advanced glycation end products (AGEs). The aim of the study was to estimate the influence of nutrition

  7. Bio-optic signatures for advanced glycation end products in the skin in streptozotocin (STZ) Induced Diabetes (Conference Presentation)

    Science.gov (United States)

    Saidian, Mayer; Ponticorvo, Adrien; Rowland, Rebecca A.; Balbado, Melisa L.; Lentsch, Griffin; Balu, Mihaela; Alexander, Micheal; Shiri, Li; Lakey, Jonathan R. T.; Durkin, Anthony J.; Kohen, Roni; Tromberg, Bruce J.

    2017-02-01

    Type 1diabetes (T1D) is an autoimmune disorder that occurs due to the rapid destruction of insulin-producing beta cells, leading to insulin deficiency and the inability to regulate blood glucose levels and leads to destructive secondary complications. Advanced glycation end (AGEs) products, the result of the cross-linking of reducing sugars and proteins within the tissues, are one of the key causes of major complications associated with diabetes such as renal failure, blindness, nerve damage and vascular changes. Non-invasive techniques to detect AGEs are important for preventing the harmful effects of AGEs during diabetes mellitus. In this study, we utilized multiphoton microscopy to image biopsies taken from control rats and compared them to biopsies taken from streptozotocin (STZ) induced adult male diabetic rats. This was done at two and four weeks after the induction of hyperglycemia (>400 mg/dL) specifically to evaluate the effects of glycation on collagen. We chose to use an in-situ multiphoton microscopy method that combines multiphoton auto-florescence (AF) and second harmonic generation (SHG) to detect the microscopic influence of glycation. Initial results show high auto-florescence levels were present on the collagen, as a result of the accumulation of AGEs only two weeks after the STZ injection and considerably higher levels were present four weeks after the STZ injection. Future projects could involve evaluating advanced glycation end products in a clinical trial of diabetic patients.

  8. Utilization of the linear mode of MALDI-TOF mass spectrometry in the study of glycation during the malting process

    Czech Academy of Sciences Publication Activity Database

    Laštovičková, Markéta; Mazanec, Karel; Smětalová, Dagmar; Bobálová, Janette

    2010-01-01

    Roč. 116, č. 3 (2010), s. 245-250 ISSN 0046-9750 R&D Projects: GA MŠk 1M0570 Institutional research plan: CEZ:AV0Z40310501 Keywords : barley * brewing * glycation Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.897, year: 2010

  9. Biodistribution of the 18F-labelled advanced glycation end products Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL)

    International Nuclear Information System (INIS)

    Bergmann, R.; Helling, R.; Henle, T.; Heichert, C.; Scheunemann, M.; Maeding, P.; Wittrisch, H.; Johannsen, B.

    2002-01-01

    After synthesis of fluorine-18 labelled analogues [ 18 F]fluorobenzoylation at the α-amino group, biodistribution and elimination of individual advanced glycation end products, namely N ε -carboxymethyllysine and N ε -carboxyethyllysine, was studied in comparison to lysine in rats after intravenous injection using positron emission tomography. (orig.)

  10. Serum levels of advanced glycation end products are associated with left ventricular diastolic function in patients with type 1 diabetes

    DEFF Research Database (Denmark)

    Berg, T J; Snorgaard, O; Faber, J

    1999-01-01

    Impairment of left ventricular diastolic function, possibly caused by increased collagen cross-linking of the cardiac muscle, is common in patients with type 1 diabetes even without coronary artery disease. Advanced glycation end products (AGEs) cross-link tissue collagen and are found within...

  11. Antibody Production with Synthetic Peptides.

    Science.gov (United States)

    Lee, Bao-Shiang; Huang, Jin-Sheng; Jayathilaka, Lasanthi P; Lee, Jenny; Gupta, Shalini

    2016-01-01

    Peptides (usually 10-20 amino acid residues in length) can be used as effectively as proteins in raising antibodies producing both polyclonal and monoclonal antibodies routinely with titers higher than 20,000. Peptide antigens do not function as immunogens unless they are conjugated to proteins. Production of high quality antipeptide antibodies is dependent upon peptide sequence selection, the success of peptide synthesis, peptide-carrier protein conjugation, the humoral immune response in the host animal, the adjuvant used, the peptide dose administered, the injection method, and the purification of the antibody. Peptide sequence selection is probably the most critical step in the production of antipeptide antibodies. Although the process for designing peptide antigens is not exact, several guidelines and computational B-cell epitope prediction methods can help maximize the likelihood of producing antipeptide antibodies that recognize the protein. Antibodies raised by peptides have become essential tools in life science research. Virtually all phospho-specific antibodies are now produced using phosphopeptides as antigens. Typically, 5-20 mg of peptide is enough for antipeptide antibody production. It takes 3 months to produce a polyclonal antipeptide antibody in rabbits that yields ~100 mL of serum which corresponds to ~8-10 mg of the specific antibody after affinity purification using a peptide column.

  12. Association of subclinical inflammation, glycated hemoglobin and risk for obstructive sleep apnea syndrome.

    Science.gov (United States)

    D'Aurea, Carolina Vicaria Rodrigues; Cerazi, Bruno Gion de Andrade; Laurinavicius, Antonio Gabriele; Janovsky, Carolina Castro Porto Silva; Conceição, Raquel Dilguerian de Oliveira; Santos, Raul D; Bittencourt, Márcio Sommer

    2017-01-01

    To investigate the inter-relation between high sensitivity C-reactive protein and glycated hemoglobin in prediction of risk of obstructive sleep apnea. We included all individuals participating in a check-up program at the Preventive Medicine Center of Hospital Israelita Albert Einstein in 2014. The Berlin questionnaire for risk of obstructive sleep apnea was used, and the high sensitivity C-reactive protein and glycated hemoglobin levels were evaluated. The sample included 7,115 participants (age 43.4±9.6 years, 24.4% women). The Berlin questionnaire showed changes in 434 (6.1%) individuals. This finding was associated with high sensitivity C-reactive protein and glycated hemoglobin levels (pem 2014. Foi aplicado o questionário de Berlin sobre risco de apneia do sono, e avaliadas as dosagens de hemoglobina glicada e proteína C-reativa de alta sensibilidade. Foram incluídos 7.115 participantes (idade 43,4±9,6 anos, 24,4% mulheres). A prevalência de alteração no questionário de Berlin foi de 434 (6,1%). A alteração do questionário de Berlin associou-se positivamente aos resultados da proteína C-reativa de alta sensibilidade e da hemoglobina glicada (pem valores abaixo do critério diagnóstico para diabetes mellitus, está associada de forma independente ao risco para síndrome da apneia obstrutiva do sono, mesmo após ajuste para obesidade e proteína C-reativa. Estes achados sugerem possível ligação fisiopatológica entre alterações na resistência insulínica e a síndrome da apneia obstrutiva do sono, que independe da obesidade ou inflamação de baixo grau.

  13. Parkinsonism-associated protein DJ-1/Park7 is a major protein deglycase that repairs methylglyoxal- and glyoxal-glycated cysteine, arginine, and lysine residues.

    Science.gov (United States)

    Richarme, Gilbert; Mihoub, Mouadh; Dairou, Julien; Bui, Linh Chi; Leger, Thibaut; Lamouri, Aazdine

    2015-01-16

    Glycation is an inevitable nonenzymatic covalent reaction between proteins and endogenous reducing sugars or dicarbonyls (methylglyoxal, glyoxal) that results in protein inactivation. DJ-1 was reported to be a multifunctional oxidative stress response protein with poorly defined function. Here, we show that human DJ-1 is a protein deglycase that repairs methylglyoxal- and glyoxal-glycated amino acids and proteins by acting on early glycation intermediates and releases repaired proteins and lactate or glycolate, respectively. DJ-1 deglycates cysteines, arginines, and lysines (the three major glycated amino acids) of serum albumin, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and aspartate aminotransferase and thus reactivates these proteins. DJ-1 prevented protein glycation in an Escherichia coli mutant deficient in the DJ-1 homolog YajL and restored cell viability in glucose-containing media. These results suggest that DJ-1-associated Parkinsonism results from excessive protein glycation and establishes DJ-1 as a major anti-glycation and anti-aging protein. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Sri Lankan black tea (Camellia sinensis L. inhibits the methylglyoxal mediated protein glycation and potentiates its reversing activity in vitro

    Directory of Open Access Journals (Sweden)

    Walimuni Kanchana Subhashini Mendis Abeysekera

    2016-02-01

    Full Text Available Objective: To evaluate inhibitory activity of methylglyoxal (MGO mediated protein glycation and ability to potentiate its reversing activity and range of antioxidant properties of Sri Lankan low grown orthodox orange pekoe grade black tea. Methods: Freeze dried black tea brew (BTB was used as the sample in this study. Antiglycation and glycation reversing activity was studied in bovine serum albumin (BSA-MGO model. Antioxidant properties were studied using total polyphenolic content, total flavonoid content, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power in vitro antioxidant assays. Results: The results demonstrated significant (P < 0.05 and dose dependant inhibition of BSA-MGO glycation [IC50: (164.30 ± 4.85 µg/mL], potentiating of its reversing activity [EC50: (235.39 ± 5.37 µg/mL] and marked antioxidant properties [total polyphenolic content: (119.55 ± 9.97 mg gallic acid equivalents/g BTB; total flavonoid content: (6.04 ± 1.26 mg quercetin equivalents/g BTB; 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2- picrylhydrazine and ferric reducing antioxidant power: (3.29 ± 0.06, (1.95 ± 0.15 and (1.31 ± 0.19 mmol Trolox equivalents/g BTB, respectively]. No correlations were observed between antioxidant activity and BSA-MGO glycation. Conclusions: The novel properties observed for Sri Lankan orange pekoe grade black tea indicate its usefulness as a supplementary beverage in managing MGO and advanced glycation end products related diseases and ailments.

  15. Advanced glycation endproducts influence the mRNA expression of RAGE, RANKL and various osteoblastic genes in human osteoblasts.

    Science.gov (United States)

    Franke, Sybille; Siggelkow, Heide; Wolf, Gunter; Hein, Gert

    2007-06-01

    Glycation reactions resulting in the generation and accumulation of advanced glycation endproducts (AGEs) are potential mechanisms by which bone protein may be altered in vivo. AGEs accumulate in the bone increasingly with age come into close contact with osteoblasts or osteoclasts. The direct effect of AGEs on bone cells has not been thoroughly investigated. This study aimed to examine whether glycated bovine serum albumin (AGE - BSA) as an AGE modulate the mRNA expression of various genes in primary human osteoblast cultures. The following parameters were included: RAGE (receptor for AGEs), alkaline phosphatase, osteocalcin, osterix and RANKL (receptor activator of nuclear factor-kappaB ligand). Primary human osteoblast cultures were obtained from bone specimens of six patients with osteoarthrosis. Human osteoblasts were treated in AGE - BSA or control-BSA (non-glycated BSA) containing medium (5 mg/ml each) over a time course of seven days. After RT-PCR the mRNA expression was measured by real-time PCR. Related to control - BSA exposure, the mRNA expression of RAGE, RANKL and osterix increased during AGE - BSA treament. For alkaline phosphatase and osteocalcin a tendency of down-regulation was found. In summary, the study presents evidence that advanced glycation end products accumulated in bone alter osteoblasts by activation the AGE - RAGE pathway (RAGE mRNA up-regulation), inducing enhanced osteoclastogenesis (RANKL mRNA up-regulation) and impaired matrix mineralization (down-regulation of alkaline phosphatase and osteocalcin mRNA). Thus, AGEs may play a functional role in the development of bone diseases (e.g. osteoporosis).

  16. S100A14 stimulates cell proliferation and induces cell apoptosis at different concentrations via receptor for advanced glycation end products (RAGE.

    Directory of Open Access Journals (Sweden)

    Qing'e Jin

    Full Text Available S100A14 is an EF-hand containing calcium-binding protein of the S100 protein family that exerts its biological effects on different types of cells. However, exact extracellular roles of S100A14 have not been clarified yet. Here we investigated the effects of S100A14 on esophageal squamous cell carcinoma (ESCC cell lines. Results demonstrated that low doses of extracellular S100A14 stimulate cell proliferation and promote survival in KYSE180 cells through activating ERK1/2 MAPK and NF-κB signaling pathways. Immunoprecipitation assay showed that S100A14 binds to receptor for advanced glycation end products (RAGE in KYSE180 cells. Inhibition of RAGE signaling by different approaches including siRNA for RAGE, overexpression of a dominant-negative RAGE construct or a RAGE antagonist peptide (AmphP significantly blocked S100A14-induced effects, suggesting that S100A14 acts via RAGE ligation. Furthermore, mutation of the N-EF hand of S100A14 (E39A, E45A virtually reduced 10 µg/ml S100A14-induced cell proliferation and ERK1/2 activation. However, high dose (80 µg/ml of S100A14 causes apoptosis via the mitochondrial pathway with activation of caspase-3, caspase-9, and poly(ADP-ribose polymerase. High dose S100A14 induces cell apoptosis is partially in a RAGE-dependent manner. This is the first study to demonstrate that S100A14 binds to RAGE and stimulates RAGE-dependent signaling cascades, promoting cell proliferation or triggering cell apoptosis at different doses.

  17. Association of Advanced Glycation End Products with coronary Artery Calcification in Japanese Subjects with Type 2 Diabetes as Assessed by Skin Autofluorescence.

    Science.gov (United States)

    Hangai, Mari; Takebe, Noriko; Honma, Hiroyuki; Sasaki, Atsumi; Chida, Ai; Nakano, Rieko; Togashi, Hirobumi; Nakagawa, Riyuki; Oda, Tomoyasu; Matsui, Mizue; Yashiro, Satoshi; Nagasawa, Kan; Kajiwara, Takashi; Takahashi, Kazuma; Takahashi, Yoshihiko; Satoh, Jo; Ishigaki, Yasushi

    2016-10-01

    Advanced glycation end products (AGE) are considered to be among the critical pathogenic factors involved in the progression of diabetic complications. Skin autofluorescence (AF), a noninvasive measurement of AGE accumulation, has been recognized as a useful and convenient marker for diabetic vascular diseases in Caucasians. This study aimed to evaluate the association of tissue AGE, assessed using skin AF, with coronary artery calcification in Japanese subjects with type 2 diabetes. In total, 122 Japanese subjects with type 2 diabetes enrolled in this cross-sectional study underwent multi-slice computed tomography for total coronary artery calcium scores (CACS) estimation and examination with a skin AF reader. Skin AF positively correlated with age, sex, diabetes duration, pulse wave velocity, systolic blood pressure, serum creatinine, and CACS. In addition, skin AF results negatively correlated with BMI, eGFR, and serum C-peptide concentration. According to multivariate analysis, age and systolic blood pressure showed strong positive correlation and eGFR showed negative correlation with skin AF values. Multiple linear regression analyses revealed a significant positive correlation between skin AF values and logCACS, independent of age, sex, diabetes duration, HbA1c, BMI, IMT, and blood pressure. However, skin AF showed no association with serum levels of AGE, such as Nε-(carboxymethyl) lysine and 3-deoxyglucosone. Skin AF results positively correlated with CACS in Japanese subjects with type 2 diabetes. This result indicates that AGE plays a role in the pathogenesis of diabetic macrovascular disease. Measurement of skin AF values may be useful for assessing the severity of diabetic complications in Japanese subjects.

  18. The receptor for advanced glycation end products is required for β‐catenin stabilization in a chemical‐induced asthma model

    Science.gov (United States)

    Yao, Lihong; Zhao, Haijin; Tang, Haixiong; Liang, Junjie; Liu, Laiyu; Dong, Hangming; Zou, Fei

    2016-01-01

    Background and Purpose Cytoplasmic retention of β‐catenin will lead to its nuclear translocation and subsequent interaction with the transcription factor TCF/LEF that regulates target gene expression. We have previously demonstrated aberrant expression of β‐catenin in a model of asthma induced by toluene diisocyanate (TDI). The aim of this study was to examine whether the receptor for advanced glycation end products (RAGE) can regulate β‐catenin expression in TDI‐induced asthma. Experimental Approach Male BALB/c mice were sensitized and challenged with TDI to generate a chemically‐induced asthma model. Inhibitors of RAGE, FPS‐ZM1 and the RAGE antagonist peptide (RAP), were injected i.p. after each challenge. Airway resistance was measured in vivo and bronchoalveolar lavage fluid was analysed. Lungs were examined by histology and immunohistochemistry. Western blotting and quantitative PCR were also used. Key Results Expression of RAGE and of its ligands HMGB1, S100A12, S100B, HSP70 was increased in TDI‐exposed lungs. These increases were inhibited by FPS‐ZM1 or RAP. Either antagonist blunted airway reactivity, airway inflammation and goblet cell metaplasia, and decreased release of Th2 cytokines. TDI exposure decreased level of membrane β‐catenin, phosphorylated Akt (Ser473), inactivated GSK3β (Ser9), dephosphorylated β‐catenin at Ser33/37/Thr41, which controls its cytoplasmic degradation, increased phosphorylated β‐catenin at Ser552, raised cytoplasmic and nuclear levels of β‐catenin and up‐regulated its targeted gene expression (MMP2, MMP7, MMP9, VEGF, cyclin D1, fibronectin), all of which were reversed by RAGE inhibition. Conclusion and Implications RAGE was required for stabilization of β‐catenin in TDI‐induced asthma, identifying protective effects of RAGE blockade in this model. PMID:27332707

  19. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  20. Association of glycated hemoglobin with carotid intimal medial thickness in Asian Indians with normal glucose tolerance.

    Science.gov (United States)

    Venkataraman, Vijayachandrika; Amutha, Anandakumar; Anbalagan, Viknesh Prabu; Deepa, Mohan; Anjana, Ranjit Mohan; Unnikrishnan, Ranjit; Vamsi, Mamilla; Mohan, Viswananthan

    2012-01-01

    To assess the association of glycated hemoglobin (HbA1c) levels with carotid intimal medial thickness (CIMT) in Asian Indians with normal glucose tolerance (NGT). Subjects with NGT were recruited from the Chennai Urban Rural Epidemiology Study carried out on a representative population of Chennai, South India. All subjects had fasting plasma glucose 5.8) (p<0.001). Regression analysis showed that HbA1c had a strong association with CIMT after adjusting for age, gender, waist circumference, systolic and diastolic blood pressure, LDL cholesterol, serum triglycerides, HOMA-IR and smoking (ß - 0.046, p=0.047). Even among subjects with NGT, there is a significant increase in CIMT with increasing levels of HbA1c, showing the value of using HbA1c for diagnosis of glucose intolerance. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Targeting the Receptor for Advanced Glycation Endproducts (RAGE): A Medicinal Chemistry Perspective

    Science.gov (United States)

    2017-01-01

    The receptor for advanced glycation endproducts (RAGE) is an ubiquitous, transmembrane, immunoglobulin-like receptor that exists in multiple isoforms and binds to a diverse range of endogenous extracellular ligands and intracellular effectors. Ligand binding at the extracellular domain of RAGE initiates a complex intracellular signaling cascade, resulting in the production of reactive oxygen species (ROS), immunoinflammatory effects, cellular proliferation, or apoptosis with concomitant upregulation of RAGE itself. To date, research has mainly focused on the correlation between RAGE activity and pathological conditions, such as cancer, diabetes, cardiovascular diseases, and neurodegeneration. Because RAGE plays a role in many pathological disorders, it has become an attractive target for the development of inhibitors at the extracellular and intracellular domains. This review describes the role of endogenous RAGE ligands/effectors in normo- and pathophysiological processes, summarizes the current status of exogenous small-molecule inhibitors of RAGE and concludes by identifying key strategies for future therapeutic intervention. PMID:28482155

  2. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts.

    Science.gov (United States)

    Li, D X; Deng, T Z; Lv, J; Ke, J

    2014-12-01

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80 ± 5.50%, PRAGE participates in and exacerbates periodontium destruction.

  3. [Expression and function of receptors for advanced glycation end products in bovine corneal endothelial cells].

    Science.gov (United States)

    Kaji, Yuichi

    2005-11-01

    Corneal endothelial cell loss is a change that occurs with age, but its mechanism is still unclear. We postulated that interaction between advanced glycation end product(AGE) and its receptors is implicated in the corneal endothelial cell loss with age. We investigated the expression of AGE receptors: receptors for AGE(RAGE) and galectin-3 in bovine corneal endothelial cells by reverse transcription-polymerase chain reaction(RT-PCR) and immunohistochemistry. In addition, we investigated the effect of AGE on the cultured corneal endothelial cells. Expression of RAGE and galectin-3 was detected in bovine corneal endothelial cells. Galectin-3 was important in the internalization of AGE. In contrast, RAGE was important in the generation of reactive oxygen species and induction of apoptosis. Based on these data, the interaction of AGE in aqueous humor and AGE receptors expressed on the corneal endothelial cells was speculated to have a role in the corneal endothelial cell loss with age.

  4. Inactivation of cellular enzymes by carbonyls and protein-bound glycation/glycoxidation products

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    dismutase, or catalase dependent, suggesting that inhibition is not radical mediated. These effects are suggested to be due to direct adduction of the free- or protein-bound carbonyls with the target enzyme. Such an interpretation is supported by the detection of the loss of thiol groups on GAPDH...... products. In this study, we have examined the effect of glucose and carbonyl compounds (methylglyoxal, glyoxal, glycolaldehyde, and hydroxyacetone), and glycation products arising from reaction of these materials with model proteins, on the activity of three key cellular enzymes: glyceraldehyde-3-phosphate...... dehydrogenase (GAPDH), glutathione reductase, and lactate dehydrogenase, both in isolation and in cell lysates. In contrast to glucose (1M, both fresh and aged for 8 weeks), which had no effect, marked inhibition of all three enzymes was observed with methylglyoxal and glyoxal. GAPDH was also inhibited...

  5. Flavan-3-ols from Ulmus davidiana var. japonica with inhibitory activity on protein glycation.

    Science.gov (United States)

    Lee, Ga Young; Jang, Dae Sik; Kim, Junghyun; Kim, Chan-Sik; Kim, Young Sook; Kim, Joo-Hwan; Kim, Jin Sook

    2008-12-01

    Four flavan-3-ols, (+)-catechin ( 1), (+)-catechin 7- O- beta- D-apiofuranoside ( 2), (+)-catechin 7- O- beta- D-xylopyranoside ( 3), (+)-catechin 7- O- beta- D-glucopyranoside ( 4), and proanthocyanidin A-1 ( 5) as well as three other constituents, isolated from an EtOAc-soluble extract of the stem barks of Ulmus davidiana var. japonica, were evaluated for inhibitory activity against the formation of AGEs. Compounds 1 - 5 exhibited a significant inhibitory activity on the formation of AGEs in an AGEs-BSA assay by specific fluorescence and this was confirmed by an indirect AGEs-ELISA. Moreover, compounds 1 and 5 markedly reduced AGEs-BSA cross-linking to collagen in a dose-dependent manner. AGEs:advanced glycation end products BSA:bovine serum albumin CC:column chromatography CD:circular dichroism.

  6. Glycated Hemoglobin Is Associated With the Growth Rate of Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Kristensen, Katrine Lawaetz; Dahl, Marie; Rasmussen, Lars Melholt

    2017-01-01

    and HbA1c in the total study population (P=0.002). Both crude and adjusted analyses identified slower growth for the group with the highest HbA1c tertile compared with the lowest HbA1c tertile. After 3 years, the mean difference was 1.8 mm (confidence interval, 0.98–2.64). Similar significant differences......OBJECTIVE—: An inverse association between abdominal aortic aneurysms (AAAs) and diabetes mellitus exists; however, the cause remains unknown. This study aimed to evaluate whether the degree of glycemia is associated with aneurysm growth. APPROACH AND RESULTS—: The study was based on VIVA trial...... (Viborg Vascular), the randomized clinically controlled screening trial for abdominal aortic aneurysm in men aged 65 to 74 years in the Central Denmark Region. The screening included measurement of the abdominal aorta by ultrasound, analysis of glycated hemoglobin (HbA1c), and follow-up for ≤5 years...

  7. Use of Human Vascular Tissue Microarrays for Measurement of Advanced Glycation Endproducts

    Science.gov (United States)

    Halushka, Marc K.; Selvin, Elizabeth; Lu, Jie; Macgregor, Anne M.; Cornish, Toby C.

    2009-01-01

    Advanced glycation endproducts (AGEs) are present in the vasculature and are associated with vascular disease. We determined levels of AGEs in eight distinct adult vascular tissues using tissue microarray (TMA) technology and associated these levels with clinical characteristics. Medium-to-large caliber blood vessels were harvested from 100 adult autopsies to create 17 TMAs. AGE levels were evaluated by IHC using a polyclonal anti-AGE antibody on over 700 unique blood vessels. Slides were digitally scanned, and quantitative analysis was performed using a color deconvolution image analysis technique. Medial AGE staining was strongly correlated between all eight blood vessels. In the media, AGE staining levels were significantly higher at older ages (p=0.009), in white subjects (pcontains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials. (J Histochem Cytochem 57:559–566, 2009) PMID:19223295

  8. The receptor for advanced glycation end products (RAGE) and the lung.

    LENUS (Irish Health Repository)

    Buckley, Stephen T

    2010-01-01

    The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface molecules. As a pattern-recognition receptor capable of binding a diverse range of ligands, it is typically expressed at low levels under normal physiological conditions in the majority of tissues. In contrast, the lung exhibits high basal level expression of RAGE localised primarily in alveolar type I (ATI) cells, suggesting a potentially important role for the receptor in maintaining lung homeostasis. Indeed, disruption of RAGE levels has been implicated in the pathogenesis of a variety of pulmonary disorders including cancer and fibrosis. Furthermore, its soluble isoforms, sRAGE, which act as decoy receptors, have been shown to be a useful marker of ATI cell injury. Whilst RAGE undoubtedly plays an important role in the biology of the lung, it remains unclear as to the exact nature of this contribution under both physiological and pathological conditions.

  9. Advanced glycation End-products (AGEs): an emerging concern for processed food industries.

    Science.gov (United States)

    Sharma, Chetan; Kaur, Amarjeet; Thind, S S; Singh, Baljit; Raina, Shiveta

    2015-12-01

    The global food industry is expected to increase more than US $ 7 trillion by 2014. This rise in processed food sector shows that more and more people are diverging towards modern processed foods. As modern diets are largely heat processed, they are more prone to contain high levels of advanced glycation end products (AGEs). AGEs are a group of complex and heterogeneous compounds which are known as brown and fluorescent cross-linking substances such as pentosidine, non-fluorescent cross-linking products such as methylglyoxal-lysine dimers (MOLD), or non-fluorescent, non-cross linking adducts such as carboxymethyllysine (CML) and pyrraline (a pyrrole aldehyde). The chemistry of the AGEs formation, absorption and bioavailability and their patho-biochemistry particularly in relation to different complications like diabetes and ageing discussed. The concept of AGEs receptor - RAGE is mentioned. AGEs contribute to a variety of microvascular and macrovascular complications through the formation of cross-links between molecules in the basement membrane of the extracellular matrix and by engaging the receptor for advanced glycation end products (RAGE). Different methods of detection and quantification along with types of agents used for the treatment of AGEs are reviewed. Generally, ELISA or LC-MS methods are used for analysis of foods and body fluids, however lack of universally established method highlighted. The inhibitory effect of bioactive components on AGEs by trapping variety of chemical moieties discussed. The emerging evidence about the adverse effects of AGEs makes it necessary to investigate the different therapies to inhibit AGEs.

  10. Trend of glycated hemoglobin testing in diabetic patients: to assess compliance with clinical practice guidelines

    International Nuclear Information System (INIS)

    Ghayur, S.; Tariq, H.

    2013-01-01

    Objective: To determine appropriate use of glycated hemoglobin (HbA1c) testing in accordance with current recommended guidelines. Study Design: Descriptive study. Place and Duration of Study: Chemical Pathology Department Shifa International Hospital, Islamabad from Oct 2011 to Oct 2012. Material and Methods: We randomly selected 170 known diabetic patients' data from our Laboratory Information System (LIS) who were retrospective analyzed for HbA1c to check for intervals and test frequency for each patient in one year. Patients with follow-up for at least one year at Shifa International Hospital, Islamabad and having their routine investigations in our chemical pathology laboratory were included. The concentrations of HbA1c for all the specimens were measured immunoturbidimetrically using a microparticle agglutination inhibition method. Four guidelines namely World Health Organization (WHO), American Diabetic Association (ADA), Canadian Diabetic Association (CDA) and National Institute for Health and Clinical Excellence (NICE) about HbA1c testing were utilized for data interpretation. All tests ordered within a 2 months period or more than 6 months following the previous order were labeled as inappropriate. Results: Only 35.8% of the patients were being properly monitored as per guidelines. Out of 64% patients who were inappropriately monitored, 12.9% had repeat orders within 2 months while 51.1% of patients were being monitored at longer interval against recommended guidelines. Conclusions: Glycated hemoglobin is a useful tool to objectively assess the prior glycemic control of patients with type 1 and type 2 diabetes. The study highlights that in large proportion of diabetic patients, HbA1c is not utilized properly as a tool to assess the risk of diabetic complications but in a small proportion is also tested unnecessarily which adds to avoidable health expenditure. (author)

  11. Gingival advanced glycation end-products in diabetes mellitus-associated chronic periodontitis: an immunohistochemical study.

    Science.gov (United States)

    Zizzi, A; Tirabassi, G; Aspriello, S D; Piemontese, M; Rubini, C; Lucarini, G

    2013-06-01

    The accumulation of advanced glycation end-products (AGEs) seems to play an important role in the development of diabetes mellitus (DM)-associated periodontitis; however, some aspects of this issue are still scarcely known, such as the expression of AGEs in type 1 DM-associated periodontitis and the clinical factors able to affect their accumulation. This study aimed to clarify these points by evaluating the expression of AGEs in DM-associated periodontitis. Sixteen systemically and periodontally healthy subjects and 48 subjects suffering from generalized, severe, chronic periodontitis (16 with type 1 DM, 16 with type 2 DM and 16 systemically healthy subjects) were studied clinically, periodontally and metabolically. The immunohistochemical expression of AGEs in gingival tissues was also evaluated. Subjects affected with type 1 DM presented a significantly higher percentage of AGE-positive cells than did subjects affected with type 2 DM, not only in the epithelium, but also in vessels and fibroblasts. A positive and significant correlation was found between gingival expression of AGEs and length of time affected with DM both in type 1 and type 2 DM; glycated hemoglobin, lipid profile, body mass index and age did not correlate significantly with gingival AGEs in any of the classes of subjects studied. Gingival AGEs are increased in both type 1 and type 2 DM-associated periodontitis; however, the clinical parameter that determines their accumulation, and therefore their degree of influence on the development of DM-associated periodontitis, may be the duration of DM. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Advanced glycation end products and their receptor contribute to ovarian ageing.

    Science.gov (United States)

    Stensen, Mette Haug; Tanbo, Tom; Storeng, Ritsa; Fedorcsak, Peter

    2014-01-01

    Do advanced glycation end products (AGE) and the receptor for advanced glycation end products (RAGE) affect the cells of the human ovarian follicle? AGE accumulate on the surface of ovarian granulosa-lutein (GL) cells and monocytes by binding to RAGE and other receptors with possible functional effects on these cells. AGE and RAGE are expressed in granulosa and theca cells, as well as in luteinized cells derived from the ovary. In this prospective cohort study, human follicle fluid-derived cells were isolated from aspirates of ovarian follicles of women who underwent assisted reproduction treatment. Immunofluorescence microscopy and multi-colour flow cytometry were used to determine the presence of AGE and RAGE on the surface of follicular fluid-derived cells and to characterize downstream effects of RAGE activation. GL cells and ovarian monocytes were found to contain AGE and RAGE and to bind AGE-bovine serum albumin (BSA) in correlation with the patients' chronological age. AGE-BSA and BSA failed to induce significantly the cleavage of caspase-3, phosphorylation of nuclear factor-κB or the binding of annexin V (the latter was marginally increased). AGE-fibronectin was found to induce detachment of cultured GL cells in vitro. The impact of AGE and RAGE in the ovary, shown here in cells in culture, remains to be affirmed in clinical settings. The ligands of RAGE and their effects in the ovary remain uncertain but this study implies that AGEs in the form of structural long-lived extracellular matrix proteins, rather than soluble AGEs, may play a role in the decline of ovarian function during ageing. The project was funded by the Norwegian Resource Centre for Women's Health, Oslo University Hospital. The authors have no conflicts of interests.

  13. A Perspective on the Maillard Reaction and the Analysis of Protein Glycation by Mass Spectrometry: Probing the Pathogenesis of Chronic Disease

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qibin; Ames, Jennifer M.; Smith, Richard D.; Baynes, John; Metz, Thomas O.

    2008-12-18

    The Maillard reaction, starting from the glycation of protein and progressing to the formation of advanced glycation end-products (AGEs), is implicated in the development of complications of diabetes mellitus, as well as in the pathogenesis of cardiovascular, renal, and neurodegenerative diseases. In this perspective review, we provide on overview on the relevance of the Maillard reaction in the pathogenesis of chronic disease and discuss traditional approaches and recent developments in the analysis of glycated proteins by mass spectrometry. We propose that proteomics approaches, particularly bottom-up proteomics, will play a significant role in analyses of clinical samples leading to the identification of new markers of disease development and progression.

  14. Radiolabelled peptides vs. nanoparticle-peptide complexes for medical applications

    International Nuclear Information System (INIS)

    Ferro F, G.

    2007-01-01

    Full text: The principle that peptide receptors can be used successfully for in vivo targeting of human cancers has been provided and the peptide-receptor radionuclide therapy for malignant tumors is a real treatment option. Targeted entry into cells is an increasingly important area of research. The diagnoses and treatment of disease by novel methods would be enhanced greatly by the efficient transport of materials to living cell nuclei. Membrane-trans locating peptides complexed to nanoparticles are small enough (30 nm) to cross the nuclear membrane and to enter the cell via receptor-mediated endocytosis, emerging as a new type of pharmaceuticals. Pharmacokinetic properties and molecular specificity of iron or gold nanoparticle-peptide complexes that do not induce biological toxicity is a topic of world interest in current and future medical investigations. Some perspectives and achievements on the preparation, pharmacokinetics and dosimetry of radiolabelled peptides versus nanoparticle-peptide complexes for medical applications are presented. (Author)

  15. Effects of glucagon-like peptide-1 receptor agonists on cardiovascular risk factors

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Vilsbøll, Tina; Knop, Filip K

    2018-01-01

    trials for diabetes therapies. To determine if different glucagon-like peptide-1 receptor agonists (GLP-1RAs) had varying effects on these CV risk factors, we reviewed 16 head-to-head trials directly comparing GLP-1RAs that included at least one of the five factors. Few trials reported statistical...... differences between GLP-1RAs in terms of systolic blood pressure (SBP), body weight and total cholesterol. Liraglutide increased heart rate vs its comparators in three separate trials. All GLP-1RAs reduced glycated haemoglobin (HbA1c), but exenatide twice daily and lixisenatide had statistically smaller...... effects compared with other GLP-1RAs. These descriptive data indicate that individual GLP-1RAs affect CV risk factors differently, potentially because of their individual pharmacokinetics and/or size. Short-acting GLP-1RAs appeared to result in smaller changes in SBP and total cholesterol compared...

  16. Glucagon-like peptide 1: A potential anti-inflammatory pathway in obesity-related asthma.

    Science.gov (United States)

    Nguyen, Dan-Vinh; Linderholm, Angela; Haczku, Angela; Kenyon, Nicholas

    2017-12-01

    Alterations in arginine metabolism and accelerated formation of advanced glycation end-products (AGEs), crucial mechanisms in obesity-related asthma, can be modulated by glucagon-like peptide 1 (GLP-1). l-arginine dysregulation in obesity promotes inflammation and bronchoconstriction. Prolonged hyperglycemia, dyslipidemia, and oxidative stress leads to production of AGEs, that bind to their receptor (RAGE) further potentiating inflammation. By binding to its widely distributed receptor, GLP-1 blunts the effects of RAGE activation and arginine dysregulation. The GLP-1 pathway, while comprehensively studied in the endocrine and cardiovascular literature, is under-recognized in pulmonary research. Insights into GLP-1 and the lung may lead to novel treatments for obesity-related asthma. Published by Elsevier Inc.

  17. Relationship between glycated hemoglobin and glucose concentrations in the adult Galician population: selection of optimal glycated hemoglobin cut-off points as a diagnostic tool of diabetes mellitus.

    Science.gov (United States)

    Botana López, Manuel Antonio; López Ratón, Mónica; Tomé, María Ausencia; Fernández Mariño, Alexis; Mato Mato, José Antonio; Rego Iraeta, Antonia; Pérez Fernández, Román; Cadarso Suárez, Carmen

    2012-10-01

    To analyze the relationship between glucose and glycated hemoglobin (HbA(1c)) in the adult Galician population, evaluate the use of HbA(1c) for the screening and diagnosis of diabetes, and calculate the diagnostic threshold required for this purpose. We analyzed data on 2848 subjects (aged 18-85 years) drawn from a study undertaken in 2004 to assess the prevalence of diabetes in Galicia. For study purposes, diabetes was defined using the criteria recommended in 2002. Participants were classified into four glucose-based groups. The relationship between glucose and HbA(1c) was described using linear regression models, generalized additive models and Spearman's correlation. Diagnostic capacity was assessed, and optimal HbA(1c) cut-off points were calculated as a diabetes marker using the receiver operating characteristic curve. Prevalence of pre-diabetes, unknown diabetes and known diabetes was 20.86, 3.37 and 4.39%, respectively. The correlations between HbA(1c) and fasting glucose were higher than those obtained for HbA(1c) and glycemia at 2h of the oral glucose overload (0.344 and 0.270, respectively). Taking glucose levels as the gold standard, a greater discriminatory capacity was obtained for HbA(1c) (area under de cruve: 0.839, 95% confidence intervals: 0.788-0.890). Based on the study criteria, the optimal minimum and maximum HbA(1c) values were 5.9% and 6.7%, respectively. HbA(1c) did not prove superior to glycemia for diagnosis of diabetes in the adult Galician population, and cannot therefore be used to replace the oral glucose tolerance test for screening and diagnosis purposes. Indeed, determination of glucose is essential to verify the diagnosis in the majority of cases. Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  18. Peptide-enhanced oral delivery of therapeutic peptides and proteins

    DEFF Research Database (Denmark)

    Kristensen, Mie; Foged, Camilla; Berthelsen, Jens

    2013-01-01

    Systemic therapy upon oral delivery of biologics, such as peptide and protein drugs is limited due to their large molecular size, their low enzymatic stability and their inability to cross the intestinal epithelium. Ways to overcome the epithelial barrier include the use of peptide-based excipients...... throughout the gastrointestinal (GI) tract, chemical stability is an inherent challenge when employing amino acid-based excipients for oral delivery, and multiple approaches have been investigated to improve this. The exact mechanisms of transepithelial translocation are discussed, and it is believed...... for oral delivery of peptide and protein drugs highlighting recent studies and the most promising compounds from these classes of peptide excipients....

  19. Peptide Signals Encode Protein Localization▿

    OpenAIRE

    Russell, Jay H.; Keiler, Kenneth C.

    2007-01-01

    Many bacterial proteins are localized to precise intracellular locations, but in most cases the mechanism for encoding localization information is not known. Screening libraries of peptides fused to green fluorescent protein identified sequences that directed the protein to helical structures or to midcell. These peptides indicate that protein localization can be encoded in 20-amino-acid peptides instead of complex protein-protein interactions and raise the possibility that the location of a ...

  20. The Equine PeptideAtlas

    DEFF Research Database (Denmark)

    Bundgaard, Louise; Jacobsen, Stine; Sorensen, Mette A.

    2014-01-01

    Equine PeptideAtlas encompassing high-resolution tandem MS analyses of 51 samples representing a selection of equine tissues and body fluids from healthy and diseased animals. The raw data were processed through the Trans-Proteomic Pipeline to yield high quality identification of proteins and peptides...... analyses, and emphasizes the value of the Equine PeptideAtlas as a resource for the design of targeted quantitative proteomic studies....

  1. Structural Characterization of Peptide Antibodies

    DEFF Research Database (Denmark)

    Chailyan, Anna; Marcatili, Paolo

    2015-01-01

    The role of proteins as very effective immunogens for the generation of antibodies is indisputable. Nevertheless, cases in which protein usage for antibody production is not feasible or convenient compelled the creation of a powerful alternative consisting of synthetic peptides. Synthetic peptides...... can be modified to obtain desired properties or conformation, tagged for purification, isotopically labeled for protein quantitation or conjugated to immunogens for antibody production. The antibodies that bind to these peptides represent an invaluable tool for biological research and discovery...

  2. One Hundred Years of Peptide Chemistry

    Indian Academy of Sciences (India)

    thus a chiral center. Today, 20 amino acids are known as genetically encoded as building blocks of peptides and proteins. Almost all of them present in peptides have L-configura- tion. D-amino acids have been found only in small peptides of bacterial cell walls, peptide antibiotics and peptides in South American frog skin.

  3. The effect of an advanced glycation end-product crosslink breaker and exercise training on vascular function in older individuals: a randomized factorial design trial.

    NARCIS (Netherlands)

    Oudegeest-Sander, M.H.; Olde Rikkert, M.G.M.; Smits, P.; Thijssen, D.H.J.; Dijk, A.P.J. van; Levine, B.D.; Hopman, M.T.E.

    2013-01-01

    Aging leads to accumulation of irreversible advanced glycation end-products (AGEs), contributing to vascular stiffening and endothelial dysfunction. When combined with the AGE-crosslink breaker Alagebrium, exercise training reverses cardiovascular aging in experimental animals. This study is the

  4. Glycation of low-density lipoproteins by methylglyoxal and glycolaldehyde gives rise to the in vitro formation of lipid-laden cells

    DEFF Research Database (Denmark)

    Brown, B E; Dean, R T; Davies, Michael Jonathan

    2005-01-01

    modification can result in unregulated cellular accumulation of lipids. In previous studies we have characterized the formation of glycated, but nonoxidized, LDL by glucose and aldehydes; in this study we examine whether glycation of LDL, in the absence of oxidation, gives rise to lipid accumulation...... in arterial wall cell types. METHODS: Glycated LDLs were incubated with macrophage, smooth muscle, or endothelial cells. Lipid loading was assessed by HPLC analysis of cholesterol and individual esters. Oxidation was assessed by cholesterol ester loss and 7-ketocholesterol formation. Cell viability...... or endothelial cells. The extent of lipid accumulation depends on the degree of glycation, with increasing aldehyde concentration or incubation time, giving rise to greater extents of particle modification and lipid accumulation. Modification of lysine residues appears to be a key determinant of cellular uptake...

  5. Peptide Vaccines for Cancer

    Directory of Open Access Journals (Sweden)

    Kono K

    2013-10-01

    Full Text Available Background: In general, the preferable characteristic of the target molecules for development of cancer vaccines are high immunogenicity, very common expression in cancer cells, specific expression in cancer cells and essential molecules for cell survival (to avoid loss of expression. We previously reported that three novel HLA-A24-restricted immunodominant peptides, which were derived from three different oncoantigens, TTK, LY6K, and IMP-3,were promising targets for cancer vaccination for esophageal squamous cell carcinoma (ESCCpatients. Then, we had performed a phase I clinical trial using three HLA-A24-binding peptides and the results had been shown to be promising for ESCC. Therefore, we further performed a multicenter, non-randomized phase II clinical trial. Patients and Methods: Sixty ESCC patients were enrolled to evaluate OS, PFS, immunological response employing ELISPOT and pentamer assays. Each of the three peptides was administered with IFA weekly. All patients received the vaccination without knowing an HLA-A type, and the HLA types were key-opened at the analysis point. Hence, the endpoints were set to evaluate differences between HLA-A*2402-positive (24(+ and -negative (24(- groups. Results: The OS in the 24 (+ group (n=35 tended to be better than that in the 24(- group (n=25 (MST 4.6 vs. 2.6 month, respectively, p = 0.121, although the difference was not statistically significant. However, the PFS in the 24(+ group was significantly better than that in the 24(- group (p = 0.032. In the 24(+ group, ELISPOT assay indicated that the LY6K-, TTK-, and IMP3-specific CTL responses were observed after the vaccination in 63%, 45%, and 60% of the 24(+ group, respectively. The patients having LY6K-, TTK-, and IMP3-specific CTL responses revealed the better OS than those not having CTL induction, respectively. The patients showing the CTL induction for multiple peptides have better clinical responses. Conclusion: The immune response induced

  6. Natriuretic peptides in cardiometabolic regulation and disease

    DEFF Research Database (Denmark)

    Zois, Nora E; Bartels, Emil D; Hunter, Ingrid

    2014-01-01

    these conditions can coexist and potentially lead to heart failure, a syndrome associated with a functional natriuretic peptide deficiency despite high circulating concentrations of immunoreactive peptides. Therefore, dysregulation of the natriuretic peptide system, a 'natriuretic handicap', might be an important...

  7. Radiolabeling of methionine containing proteins and peptides

    International Nuclear Information System (INIS)

    Garlick, R.K.; Jirousek, L.

    1986-01-01

    A process for radiolabeling methionine-containing peptides and proteins is disclosed. The process comprises the steps of oxidizing the protein or peptide, radiolabeling and reducing the radiolabeled protein or peptide. (author)

  8. An advanced glycation end product (AGE)-receptor for AGEs (RAGE) axis restores adipogenic potential of senescent preadipocytes through modulation of p53 protein function.

    Science.gov (United States)

    Chen, Chih-Yu; Abell, Allison Martorano; Moon, Yang Soo; Kim, Kee-Hong

    2012-12-28

    The impaired adipogenic potential of senescent preadipocytes is a hallmark of adipose aging and aging-related adipose dysfunction. Although advanced glycation end products (AGEs) derived from both foods and endogenous nonenzymatic glycation and AGE-associated signaling pathways are known to play a key role in aging and its related diseases, the role of AGEs in adipose aging remains elusive. We show a novel pro-adipogenic function of AGEs in replicative senescent preadipocytes and mouse embryonic fibroblasts, as well as primary preadipocytes isolated from aged mice. Using glycated bovine serum albumin (BSA) as a model protein of AGEs, we found that glycated BSA restores the impaired adipogenic potential of senescent preadipocytes in vitro and ex vivo. However, glycated BSA showed no effect on adipogenesis in nonsenescent preadipocytes. The AGE-induced receptor for AGE (RAGE) expression is required for the pro-adipogenic function of AGEs in senescent preadipocytes. RAGE is required for impairment of p53 expression and p53 function in regulating p21 expression in senescent preadipocytes. We also observed a direct binding between RAGE and p53 in senescent preadipocytes. Taken together, our findings reveal a novel pro-adipogenic function of the AGE-RAGE axis in p53-regulated adipogenesis of senescent preadipocytes, providing new insights into aging-dependent adiposity by diet-driven and/or endogenous glycated proteins.

  9. 3-Deoxyglucosone: a potential glycating agent accountable for structural alteration in H3 histone protein through generation of different AGEs.

    Directory of Open Access Journals (Sweden)

    Jalaluddin M Ashraf

    Full Text Available Advanced glycation end-products (AGEs are heterogeneous group of compounds, known to be implicated in diabetic complications. One of the consequences of the Maillard reaction is attributed to the production of reactive intermediate products such as α-oxoaldehydes. 3-deoxyglucosone (3-DG, an α-oxoaldehyde has been found to be involved in accelerating vascular damage during diabetes. In the present study, calf thymus histone H3 was treated with 3-deoxyglucosone to investigate the generation of AGEs (Nε-carboxymethyllysine, pentosidine, by examining the degree of side chain modifications and formation of different intermediates and employing various physicochemical techniques. The results clearly indicate the formation of AGEs and structural changes upon glycation of H3 by 3-deoxyglucosone, which may hamper the normal functioning of H3 histone, that may compromise the veracity of chromatin structures and function in secondary complications of diabetes.

  10. Correlation Between Glycated Hemoglobin and Homa Indices in Type 2 Diabetes Mellitus: Prediction of Beta-Cell Function from Glycated Hemoglobin.

    Science.gov (United States)

    Al-Hakeim, Hussein Kadhem; Abdulzahra, Mohammed Saied

    2015-04-01

    The present study aimed to determine the most efficient insulin resistance function related to glycemic control expressed as glycated hemoglobin (HbA1c) in type 2 diabetes mellitus patients (T2DM). The other aim is to derive equations for the prediction of beta cell functions containing HbA1c as a parameter in addition to fasting glucose and insulin. T2DM Patients were grouped according to the following: (1) degree of control (good, fair, and poor control) and (2) insulin resistance as observed in obtained data and significant differences revealed by the homeostasis model assessment (HOMA) of related parameters (insulin resistance = HOMA2IR, beta-cell function = HOMA%B, and insulin sensitivity = HOMA%S) among groups. Correlations and forecasting regression analysis were calculated. HbA1c was found to be correlated with insulin resistance parameters in T2DM subgroups. This correlation was also significantly correlated with HOMA%B and the quantitative insulin sensitivity check index (QUICKI) in fair and poor control groups. Regression analysis was used to predict the forecasting equations for HOMA%B. The best applicable equations were derived for healthy control (HOMA2%B=-1.76*FBG+5.00*Insulin+4.69*HbA1c+189.84) and poor control groups (HOMA2%B=0.001* FBG+0.5*Insulin-8.67*HbA1c+101.96). These equations could be used to predict β-cell function (HOMA%B) after FBG, insulin and HbA1c values were obtained for healthy and poor control groups. In the good and fair control groups, the applicability of the HOMA model fails to yield appropriate results. Beta-cell function is correlated with QUICKI and HbA1c and could be predicted properly from HbA1c, insulin, and glucose in the healthy and poor control groups. New regression equations were established that involve HbA1c.

  11. Glycated hemoglobin level is significantly associated with the severity of coronary artery disease in non-diabetic adults

    OpenAIRE

    Cai, Anping; Li, Guang; Chen, Jiyan; Li, Xida; Wei, Xuebiao; Li, Liwen; Zhou, Yingling

    2014-01-01

    Background To investigate relationship between glycated hemoglobin (HbA1c) level and coronary artery disease (CAD) severity. Methods Observational study was conducted and 573 participants were enrolled and baseline characteristics were collected. Clinical presentations in terms of stable angina, unstable angina or acute myocardial infarction were diagnosed. All participants were performed coronary angiography to figure out the numbers of coronary artery stenosis in terms of none-stenosis (< 5...

  12. Peptide radiopharmaceuticals in nuclear medicine

    International Nuclear Information System (INIS)

    Blok, D.; Vermeij, P.; Feitsma, R.I.J.; Pauwels, E.J.K.

    1999-01-01

    This article reviews the labelling of peptides that are recognised to be of interest for nuclear medicine or are the subject of ongoing nuclear medicine research. Applications and approaches to the labelling of peptide radiopharmaceuticals are discussed, and drawbacks in their development considered. (orig.)

  13. Antimicrobial peptides in the airway.

    Science.gov (United States)

    Laube, D M; Yim, S; Ryan, L K; Kisich, K O; Diamond, G

    2006-01-01

    The airway provides numerous defense mechanisms to prevent microbial colonization by the large numbers of bacteria and viruses present in ambient air. An important component of this defense is the antimicrobial peptides and proteins present in the airway surface fluid (ASF), the mucin-rich fluid covering the respiratory epithelium. These include larger proteins such as lysozyme and lactoferrin, as well as the cationic defensin and cathelicidin peptides. While some of these peptides, such as human beta-defensin (hBD)-1, are present constitutively, others, including hBD2 and -3 are inducible in response to bacterial recognition by Toll-like receptor-mediated pathways. These peptides can act as microbicides in the ASF, but also exhibit other activities, including potent chemotactic activity for cells of the innate and adaptive immune systems, suggesting they play a complex role in the host defense of the airway. Inhibition of antimicrobial peptide activity or gene expression can result in increased susceptibility to infections. This has been observed with cystic fibrosis (CF), where the CF phenotype leads to reduced antimicrobial capacity of peptides in the airway. Pathogenic virulence factors can inhibit defensin gene expression, as can environmental factors such as air pollution. Such an interference can result in infections by airway-specific pathogens including Bordetella bronchiseptica, Mycobacterium tuberculosis, and influenza virus. Research into the modulation of peptide gene expression in animal models, as well as the optimization of peptide-based therapeutics shows promise for the treatment and prevention of airway infectious diseases.

  14. Peptide-LNA oligonucleotide conjugates

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Hansen, Lykke Haastrup; Vester, Birte

    2013-01-01

    properties, peptides were introduced into oligonucleotides via a 2'-alkyne-2'-amino-LNA scaffold. Derivatives of methionine- and leucine-enkephalins were chosen as model peptides of mixed amino acid content, which were singly and doubly incorporated into LNA/DNA strands using highly efficient copper...

  15. Chemical Synthesis of Antimicrobial Peptides.

    Science.gov (United States)

    Münzker, Lena; Oddo, Alberto; Hansen, Paul R

    2017-01-01

    Solid-phase peptide synthesis (SPPS) is the method of choice for chemical synthesis of peptides. In this nonspecialist review, we describe commonly used resins, linkers, protecting groups, and coupling reagents in 9-fluorenylmethyloxycarbonyl (Fmoc) SPPS. Finally, a detailed protocol for manual Fmoc SPPS is presented.

  16. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    N.D. Zegers (Netty)

    1995-01-01

    textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

  17. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

  18. Urinary Peptides in Rett Syndrome.

    Science.gov (United States)

    Solaas, K. M.; Skjeldal, O.; Gardner, M. L. G.; Kase, B. F.; Reichelt, K. L.

    2002-01-01

    A study found a significantly higher level of peptides in the urine of 53 girls with Rett syndrome compared with controls. The elevation was similar to that in 35 girls with infantile autism. Levels of peptides were lower in girls with classic Rett syndrome than those with congenital Rett syndrome. (Contains references.) (Author/CR)

  19. Solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Jensen, Knud Jørgen

    2013-01-01

    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  20. An additional measurement of glycated albumin can help prevent missed diagnosis of diabetes in Chinese population.

    Science.gov (United States)

    He, Xingxing; Ying, Lingwen; Ma, Xiaojing; Shen, Yun; Su, Hang; Peng, Jiahui; Wang, Yufei; Bao, Yuqian; Zhou, Jian; Jia, Weiping

    2017-12-01

    In subjects who present a first fasting plasma glucose (FPG 1 ) ≥7.0mmol/l without classic symptoms of diabetes, diagnosis of diabetes will likely be missed without an additional oral glucose tolerance test (OGTT) in the Chinese population. Recent studies have shown that glycated albumin (GA) has advantages in reflecting postprandial hyperglycemia. Therefore, the present study evaluated whether additional measurement of GA could reduce the rate of missed diagnosis of diabetes. A total of 1287 participants (711 men, 576 women) with a FPG 1 ≥7.0mmol/l without classic symptoms of diabetes were enrolled and underwent a 75-g OGTT. Serum GA was measured by a liquid enzyme method. Diabetes was diagnosed based on the 2010 American Diabetes Association (ADA) criteria. A total of 992 (77.08%) participants were diagnosed diabetes by OGTT and glycated hemoglobin A 1c (HbA 1c ). The diagnostic validity of 2-h postload plasma glucose (2hPG) was superior to other glycemic index (the diagnostic sensitivity of 2hPG, HbA 1c , the second FPG (FPG 2 ) was 87.50%, 73.99%, 63.21%, respectively). Without 2hPG after OGTT, repeat testing of FPG 2 alone would result in missed diagnosis of 36.79% of diabetic participants, whereas testing FPG 2 with HbA 1c was associated with a missed diagnosis rate of 14.31%. While using the combined criteria of FPG 2 ≥7.0mmol/l and/or HbA 1c ≥6.5% and/or GA≥17.1%, the rate of missed diagnosis was merely 9.48%. That is, the rate of missed diagnosis was reduced by 33.75% with the addition of GA measurement. The k value reflecting the consistency of diagnosis between the FPG 2 and/or HbA 1c and/or GA criteria and the 2010 ADA criteria was 0.788. For subjects with FPG 1 ≥7.0mmol/l without classic symptoms of diabetes, additional measurement of GA can help prevent missed diagnosis of diabetes in Chinese population. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. [The effect of valsartan on the expression of the receptor for advanced glycation end products in human glomerular mesangial cells].

    Science.gov (United States)

    Zhong, Lin-na; Huang, Guo-liang; Feng, Min; Zhang, Ying

    2011-08-01

    To elucidate the effect of valsartan on human glomerular mesangial cells oxidative stress and the expression of the receptor for advanced glycation end products (RAGE) induced by the advanced glycation end-products (AGEs). Human glomerular mesangial cells were treated with advanced glycation end-product-bovine serum albumin (AGE-BSA) in the presence of valsartan. The reactive oxygen species (ROS) in cells were measured by Flow cytometry, and the mRNA of p47 phox, which was the primary subunits of NADPH oxidase, was detected by semi-quantitative reberse transcription polymerase chain reaction (RT-PCR). The mRNA of RAGE was detected by RT-PCR and the RAGE protein was assayed by immunocytochemistry. The product of ROS, and the expression of p47 phox and RAGE in mesangial cells, which were treated with AGE-BSA in the presence of valsartan, were down-regulated compared with the groups treated with AGE-BSA (P RAGE, ROS and p47(phox) in mesangial cells. Valsartan could inhibit RAGE expression through downregulation of oxidative stress.

  2. Cytoprotective role of astaxanthin against glycated protein/iron chelate-induced toxicity in human umbilical vein endothelial cells.

    Science.gov (United States)

    Nishigaki, Ikuo; Rajendran, Peramaiyan; Venugopal, Ramachandran; Ekambaram, Gnapathy; Sakthisekaran, Dhanapal; Nishigaki, Yutaka

    2010-01-01

    Astaxanthin (ASX), a red carotenoid pigment with no pro-vitamin A activity, is a biological antioxidant that occurs naturally in a wide variety of plants, algae and seafoods. This study investigated whether ASX could inhibit glycated protein/iron chelate-induced toxicity in human umbilical-vein endothelial cells (HUVEC) by interfering with ROS generation in these cells. Glycated fetal bovine serum (GFBS) was prepared by incubating fetal bovine serum (FBS) with high-concentration glucose. Stimulation of cultured HUVECs with 50 mm 1 mL of GFBS significantly enhanced lipid peroxidation and decreased antioxidant enzyme activities and levels of phase II enzymes. However, preincubation of the cultures with ASX resulted in a marked decrease in the level of lipid peroxide (LPO) and an increase in the levels of antioxidant enzymes in an ASX concentration-dependent manner. These results demonstrate that ASX could inhibit LPO formation and enhance the antioxidant enzyme status in GFBS/iron chelate-exposed endothelial cells by suppressing ROS generation, thereby limiting the effects of the AGE-RAGE interaction. The results indicate that ASX could have a beneficial role against glycated protein/iron chelate-induced toxicity by preventing lipid and protein oxidation and increasing the activity of antioxidant enzymes. (c) 2009 John Wiley & Sons, Ltd.

  3. Development of a screen-printed carbon electrode based disposable enzyme sensor strip for the measurement of glycated albumin.

    Science.gov (United States)

    Hatada, Mika; Tsugawa, Wakako; Kamio, Eri; Loew, Noya; Klonoff, David C; Sode, Koji

    2017-02-15

    Glycated proteins, such as glycated hemoglobin (HbA1c) or glycated albumin (GA) in the blood, are essential indicators of glycemic control for diabetes mellitus. Since GA, compared to HbA1c, is more sensitive to short term changes in glycemic levels, GA is expected to be used as an alternative or together with HbA1c as a surrogate marker indicator for glycemic control. In this paper we report the development of a sensing system for measuring GA by combining an enzyme analysis method, which is already used in clinical practice, with electrochemical principles. We used fructosyl amino acid oxidase, hexaammineruthenium(III) chloride as the electron mediator, and an inexpensive and economically attractive screen-printed carbon electrode. We used chronoamperometry to measure protease-digested GA samples. The developed sensor strips were able to measure protease-digested samples containing GA in very small sample volumes (1.3μL) within about 1min. We also prepared enzyme sensor strips suitable for clinical use in which the enzyme and the mediator were deposited and dried on. This sensor system showed a clear correlation between the GA concentration and the resulting current. The strips were stable following 3 months of storage at 37°C. We conclude that this disposable enzyme sensor strip system for measuring GA is suitable for point-of-care test (POCT) applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Limited hydrolysis combined with controlled Maillard-induced glycation does not reduce immunoreactivity of soy protein for all sera tested.

    Science.gov (United States)

    Walter, Jordan; Greenberg, Yana; Sriramarao, P; Ismail, Baraem P

    2016-12-15

    Combining proteolysis and Maillard-induced glycation was investigated to reduce the immunoreactivity of soy protein. Soy protein was hydrolyzed by Alcalase following response surface methodology utilizing three variables, temperature, time, and enzyme:substrate ratio, with the degree of hydrolysis (DH) and percent reduction in immunoreactivity as response variables. Western blots and ELISA were used to evaluate immunoreactivity using human sera. Data were fitted to appropriate models and prediction equations were generated to determine optimal hydrolysis conditions. The hydrolysate produced under optimized conditions was subjected to glycation with dextran. Hydrolysate produced under optimal conditions had 7.8% DH and a percent reduction in immunoreactivity ranging from 20% to 52%, depending on the sera used. Upon glycation, immunoreactivity was further reduced only when using serum that had the highest soy-specific IgE. This work revealed limitations and provided premises for future studies intended to prove the potency of the combined modification approach to produce a hypoallergenic protein ingredient. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Maize Bioactive Peptides against Cancer

    Science.gov (United States)

    Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

    2017-06-01

    Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

  6. Cathepsin-Mediated Cleavage of Peptides from Peptide Amphiphiles Leads to Enhanced Intracellular Peptide Accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Acar, Handan [Institute; Department; Samaeekia, Ravand [Institute; Department; Schnorenberg, Mathew R. [Institute; Department; Medical; Sasmal, Dibyendu K. [Institute; Huang, Jun [Institute; Tirrell, Matthew V. [Institute; Institute; LaBelle, James L. [Department

    2017-08-24

    Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation, and PA monomers are internalized via endocytosis. However, endocytotic sequestration and steric hindrance from the lipid tail are two major mechanisms that limit PA efficacy to target intracellular PPIs. To address these problems, we have constructed a PA platform consisting of cathepsin-B cleavable PAs in which a selective p53-based inhibitory peptide is cleaved from its lipid tail within endosomes, allowing for intracellular peptide accumulation and extracellular recycling of the lipid moiety. We monitor for cleavage and follow individual PA components in real time using a resonance energy transfer (FRET)-based tracking system. Using this platform, components in real time using a Forster we provide a better understanding and quantification of cellular internalization, trafficking, and endosomal cleavage of PAs and of the ultimate fates of each component.

  7. Purification and use of E. coli peptide deformylase for peptide deprotection in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia; Sonke, Theo; Quaedflieg, Peter J.; Janssen, Dick B.

    Peptide deformylases (PDFs) catalyze the removal of the formyl group from the N-terminal methionine residue in nascent polypeptide chains in prokaryotes. Its deformylation activity makes PDF an attractive candidate for the biocatalytic deprotection of formylated peptides that are used in

  8. Comparative LC-MS/MS profiling of free and protein-bound early and advanced glycation-induced lysine modifications in dairy products

    International Nuclear Information System (INIS)

    Hegele, Joerg; Buetler, Timo; Delatour, Thierry

    2008-01-01

    Free and protein-bound forms of early and advanced glycation-induced lysine (Lys) modifications were quantified in dairy products by LC-MS/MS using a stable isotope dilution assay. The glycation profiles for N ε -fructoselysine (FL), N ε -carboxymethyllysine (CML) and pyrraline (Pyr) were monitored in raw and processed cow milk to investigate whether free glycation products could serve as fast and simple markers to assess the extent of protein glycation in dairy products. In all milk samples, the fraction of free glycation adducts was predominantly composed of advanced modifications, e.g. 8.34 ± 3.81 nmol CML per μmol of free Lys (Lys free ) and 81.5 ± 87.8 nmol Pyr μmol -1 Lys free -1 vs. 3.72 ± 1.29 nmol FL μmol -1 Lys free -1 . In contrast, the protein-bound early glycation product FL considerably outweighed the content of CML and Pyr in milk proteins of raw and processed cow milk, whereas severely heat treated milk products, e.g. condensed milk, contained a higher amount of protein-bound advanced glycation adducts. Typical values recorded for milk samples processed under mild conditions were 0.47 ± 0.08 nmol FL μmol -1 of protein-bound Lys (Lys p-b ), 0.04 ± 0.03 nmol CML μmol -1 Lys p-b -1 and 0.06 ± 0.02 nmol Pyr μmol -1 Lys p-b -1 . It was particularly noticeable, however, that mild heat treatment of raw milk, i.e. pasteurization and UHT treatment, did not significantly increase the amount of both free and protein-bound Lys modifications. In conclusion, the profiles of free and protein-bound glycation-induced Lys modifications were found to be different and a screening of free glycation adducts does, therefore, not allow for a conclusion about the protein glycation status of dairy products

  9. Glycation in human fingernail clippings using ATR-FTIR spectrometry, a new marker for the diagnosis and monitoring of diabetes mellitus.

    Science.gov (United States)

    Coopman, Renaat; Van de Vyver, Thijs; Kishabongo, Antoine Sadiki; Katchunga, Philippe; Van Aken, Elisabeth H; Cikomola, Justin; Monteyne, Tinne; Speeckaert, Marijn M; Delanghe, Joris R

    2017-01-01

    Although HbA1c is a good diagnostic tool for diabetes, the precarity of the health system and the costs limit the use of this biomarker in developing countries. Fingernail clippings contain ±85% of keratins, which are prone to glycation. Nail keratin glycation may reflect the average glycemia over the last months. We explored if attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) can be used as a non-invasive tool for assessing glycation in diabetes. Using ATR-FTIR spectroscopy, glycation and deglycation experiments with fructosamine 3-kinase allowed to identify the spectrum that corresponds with keratin glycation in fingernail clippings. Clippings of 105 healthy subjects and 127 diabetics were subjected to the standardized ATR-FTIR spectroscopy method. In vitro glycation resulted in an increased absorption at 1047cm -1 . Following enzymatic deglycation, this peak diminished significantly, proving that the AUC between 970 and 1140cm -1 corresponded with glycated proteins. Within-run CV of the assay was 3%. Storage of nail clippings at 37°C for 2weeks did not significantly change results. In diabetics, glycated nail protein concentrations (median: 1.51μmol/g protein, IQR: 1.37-1.85μmol/g protein) were significantly higher than in the controls (median: 1.19μmol/g protein, IQR: 1.09-1.26μmol/g protein) (p<0.0001). ROC analysis yielded an AUC of 0.92 at a cut-off point of 1.28μmol/g nail (specificity: 82%; sensitivity: 90%). No correlation was observed between the glycated nail protein concentrations and HbA1c. Protein glycation analysis in fingernails with ATR-FTIR spectroscopy could be an alternative affordable technique for diagnosing and monitoring diabetes. As the test does not consume reagents, and the preanalytical phase is extremely robust, the test could be particularly useful in developing countries. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  10. Comparative LC-MS/MS profiling of free and protein-bound early and advanced glycation-induced lysine modifications in dairy products

    Energy Technology Data Exchange (ETDEWEB)

    Hegele, Joerg [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)], E-mail: joerg.hegele@rdls.nestle.com; Buetler, Timo; Delatour, Thierry [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)

    2008-06-09

    Free and protein-bound forms of early and advanced glycation-induced lysine (Lys) modifications were quantified in dairy products by LC-MS/MS using a stable isotope dilution assay. The glycation profiles for N{sup {epsilon}}-fructoselysine (FL), N{sup {epsilon}}-carboxymethyllysine (CML) and pyrraline (Pyr) were monitored in raw and processed cow milk to investigate whether free glycation products could serve as fast and simple markers to assess the extent of protein glycation in dairy products. In all milk samples, the fraction of free glycation adducts was predominantly composed of advanced modifications, e.g. 8.34 {+-} 3.81 nmol CML per {mu}mol of free Lys (Lys{sub free}) and 81.5 {+-} 87.8 nmol Pyr {mu}mol{sup -1} Lys{sub free}{sup -1} vs. 3.72 {+-} 1.29 nmol FL {mu}mol{sup -1} Lys{sub free}{sup -1}. In contrast, the protein-bound early glycation product FL considerably outweighed the content of CML and Pyr in milk proteins of raw and processed cow milk, whereas severely heat treated milk products, e.g. condensed milk, contained a higher amount of protein-bound advanced glycation adducts. Typical values recorded for milk samples processed under mild conditions were 0.47 {+-} 0.08 nmol FL {mu}mol{sup -1} of protein-bound Lys (Lys{sub p-b}), 0.04 {+-} 0.03 nmol CML {mu}mol{sup -1} Lys{sub p-b}{sup -1} and 0.06 {+-} 0.02 nmol Pyr {mu}mol{sup -1} Lys{sub p-b}{sup -1}. It was particularly noticeable, however, that mild heat treatment of raw milk, i.e. pasteurization and UHT treatment, did not significantly increase the amount of both free and protein-bound Lys modifications. In conclusion, the profiles of free and protein-bound glycation-induced Lys modifications were found to be different and a screening of free glycation adducts does, therefore, not allow for a conclusion about the protein glycation status of dairy products.

  11. Increased levels of circulating advanced glycation end-products in menopausal women with osteoporosis.

    Science.gov (United States)

    Yang, Deng-Ho; Chiang, Tsay-I; Chang, I-Chang; Lin, Fu-Huang; Wei, Cheng-Chung; Cheng, Ya-Wen

    2014-01-01

    Advanced glycation end-products (AGEs) can accumulate in organs and tissues during ageing and diabetes. Increased levels of AGEs are found in the bone tissue of patients with osteoporosis. The purpose of this study was to evaluate circulating AGEs in patients with osteoporosis. We evaluated plasma AGEs, osteoporosis-related biomarkers, and bone mass in 82 menopausal women with osteoporosis or osteopenia, 16 young women with osteopenia, and 43 healthy women without osteoporosis or osteopenia. Higher levels of serum AGEs were found in the osteoporosis or osteopenia group compared to healthy women (P 8.12 U/mL) had a 5.34-fold risk of osteopenia regarding lumbar spine T-score and a 3.31-fold risk of osteopenia regarding the hip T-score. Serum AGEs could be used to monitor the severity and progression of osteoporosis. An increased serum level of AGEs was associated with impaired bone formation and was a risk factor for the development of osteoporosis. Targeting AGEs may represent a novel therapeutic approach for primary or secondary osteoporosis.

  12. Anthraquinones from the seeds of Cassia tora with inhibitory activity on protein glycation and aldose reductase.

    Science.gov (United States)

    Jang, Dae Sik; Lee, Ga Young; Kim, Young Sook; Lee, Yun Mi; Kim, Chan-Sik; Yoo, Jeong Lim; Kim, Jin Sook

    2007-11-01

    Nine anthraquinones, aurantio-obtusin (1), chryso-obtusin (2), obtusin (3), chryso-obtusin-2-O-beta-D-glucoside (4), physcion (5), emodin (6), chrysophanol (7), obtusifolin (8), and obtusifolin-2-O-beta-D-glucoside (9), isolated from an EtOAc-soluble extract of the seeds of Cassia tora, were subjected to in vitro bioassays to evaluate their inhibitory activity against advanced glycation end products (AGEs) formation and rat lens aldose reductase (RLAR). Among the isolates, compounds 6 and 8 exhibited a significant inhibitory activity on AGEs formation with observed IC(50) values of 118 and 28.9 microM, respectively, in an AGEs-bovine serum albumin (BSA) assay by specific fluorescence. Furthermore, compounds 6 and 8 inhibited AGEs-BSA formation more effectively than aminoguanidine, an AGEs inhibitor, by indirect AGEs-ELISA. N(epsilon)-Carboxymethyllysine (CML)-BSA formation was also inhibited by compounds 6 and 8. Whereas compounds 1, 4, and 6 showed a significant inhibitory activity on RLAR with IC(50) values of 13.6, 8.8, and 15.9 microM, respectively.

  13. Receptor for Advanced Glycation End Products and Its Involvement in Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Yaw Kuang Chuah

    2013-01-01

    Full Text Available The receptor for advanced glycation end products (RAGE is a transmembrane receptor of the immunoglobulin superfamily, capable of binding a broad repertoire of ligands. RAGE-ligands interaction induces a series of signal transduction cascades and lead to the activation of transcription factor NF-κB as well as increased expression of cytokines, chemokines, and adhesion molecules. These effects endow RAGE with the role in the signal transduction from pathogen substrates to cell activation during the onset and perpetuation of inflammation. RAGE signaling and downstream pathways have been implicated in a wide spectrum of inflammatory-related pathologic conditions such as arteriosclerosis, Alzheimer's disease, arthritis, acute respiratory failure, and sepsis. Despite the significant progress in other RAGE studies, the functional importance of the receptor in clinical situations and inflammatory diseases still remains to be fully realized. In this review, we will summarize current understandings and lines of evidence on the molecular mechanisms through which RAGE signaling contributes to the pathogenesis of the aforementioned inflammation-associated conditions.

  14. Receptor for advanced glycation end products (RAGE) knockout reduces fetal dysmorphogenesis in murine diabetic pregnancy.

    Science.gov (United States)

    Ejdesjö, Andreas; Brings, Sebastian; Fleming, Thomas; Fred, Rikard G; Nawroth, Peter P; Eriksson, Ulf J

    2016-07-01

    The receptor for Advanced Glycation End products (RAGE) is implicated in the pathogenesis of diabetic complications, but its importance in diabetic embryopathy is unclear. We therefore investigated the role of RAGE in diabetic embryopathy using streptozotocin induced diabetes in female wild type (WT) C57Bl/6N and RAGE knockout C57Bl/6N (RAGE(-/-)) mice, mated with control males of the same genotype. Maternal diabetes induced more fetal resorption and malformation (facial skeleton, neural tube) in the WT than in the RAGE(-/-) fetuses. Maternal plasma glucose and methylgyoxal concentrations, as well as embryonic N(ε)-carboxymethyl-lysine (CML) levels were increased to the same extent in diabetic WT and RAGE(-/-) pregnancy. However, maternal diabetes induced increased fetal hepatic isoprostane 8-iso-PGF2α levels (oxidative stress marker) and embryonic activation of NFκB in WT only (not in RAGE(-/-) embryos). The association between RAGE knockout and diminished embryonic dysmorphogenesis in diabetic pregnancy suggests that embryonic RAGE activation is involved in diabetic embryopathy. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Receptor for advanced glycation end products (RAGE)-mediated cytotoxicity of 3-hydroxypyridinium derivatives.

    Science.gov (United States)

    Murakami, Yoto; Fujino, Takayuki; Hasegawa, Toshiki; Kurachi, Ryotaro; Miura, Aya; Daikoh, Takumi; Usui, Teruyuki; Hayase, Fumitaka; Watanabe, Hirohito

    2018-02-01

    Advanced glycation end products (AGEs) formed from glyceraldehyde (Gcer) and glycolaldehyde (Gcol) are involved in the pathogenesis of diabetic complications, via interactions with a receptor for AGEs (RAGE). In this study, we aimed to elucidate the RAGE-binding structure in Gcer and Gcol-derived AGEs and identify the minimal moiety recognized by RAGE. Among Gcer and Gcol-derived AGEs, GLAP (glyceraldehyde-derived pyridinium) and GA-pyridine elicited toxicity in PC12 neuronal cells. The toxic effects of GLAP and GA-pyridine were suppressed in the presence of anti-RAGE antibody or the soluble form of RAGE protein. Furthermore, the cytotoxicity test using GLAP analog compounds indicated that the 3-hydroxypyridinium (3-HP) structure is sufficient for RAGE-dependent toxicity. Surface plasmon resonance analysis showed that 3-HP derivatives directly interact with RAGE. These results indicate that GLAP and GA-pyridine are RAGE-binding epitopes, and that 3-HP, a common moiety of GLAP and GA-pyridine, is essential for the interaction with RAGE.

  16. Aptasensor based optical detection of glycated albumin for diabetes mellitus diagnosis

    Science.gov (United States)

    Ghosh, Shreya; Datta, Debopam; Cheema, Mehar; Dutta, Mitra; Stroscio, Michael A.

    2017-10-01

    Glycated albumin (GA) has been reported as an important biomarker for diabetes mellitus. This study investigates an optical sensor comprised of deoxyribonucleic acid (DNA) aptamer, semiconductor quantum dot and gold (Au) nanoparticle for the detection of GA. The system functions as a ‘turn on’ sensor because an increase in photoluminescence intensity is observed upon the addition of GA to the sensor. This is possibly because of the structure of the DNA aptamer, which folds to form a large hairpin loop before the addition of the analyte and is assumed to open up after the addition of target to the sensor in order to bind to GA. This pushes the quantum dot and the Au nanoparticle away causing an increase in photoluminescence. A linear increase in photoluminescence intensity and quenching efficiency of the sensor is observed as the GA concentration is varied between 0-14 500 nM. Time based photoluminescence studies with the sensor show the decrease in binding rate of the aptamer to the target within a specific time period. The sensor was found to have a higher selectivity towards GA than other control proteins. Further investigation of this simple sensor with greater number of clinical samples can open up avenues for an efficient diagnosis and monitoring of diabetes mellitus when used in conjunction with the traditional method of glucose level monitoring.

  17. Advanced glycation end products (AGEs) and their receptor (RAGE) induce apoptosis of periodontal ligament fibroblasts

    International Nuclear Information System (INIS)

    Li, D.X.; Deng, T.Z.; Lv, J.; Ke, J.

    2014-01-01

    Diabetics have an increased prevalence of periodontitis, and diabetes is one of the causative factors of severe periodontitis. Apoptosis is thought to be involved in this pathogenic relationship. The aim of this study was to investigate apoptosis in human periodontal ligament (PDL) fibroblasts induced by advanced glycation end products (AGEs) and their receptor (RAGE). We examined the roles of apoptosis, AGEs, and RAGE during periodontitis in diabetes mellitus using cultured PDL fibroblasts that were treated by AGE-modified bovine serum albumin (AGE-BSA), bovine serum albumin (BSA) alone, or given no treatment (control). Microscopy and real-time quantitative PCR indicated that PDL fibroblasts treated with AGE-BSA were deformed and expressed higher levels of RAGE and caspase 3. Cell viability assays and flow cytometry indicated that AGE-BSA reduced cell viability (69.80±5.50%, P<0.01) and increased apoptosis (11.31±1.73%, P<0.05). Hoechst 33258 staining and terminal-deoxynucleotidyl transferase-mediated nick-end labeling revealed that AGE-BSA significantly increased apoptosis of PDL fibroblasts. The results showed that the changes in PDL fibroblasts induced by AGE-BSA may explain how AGE-RAGE participates in and exacerbates periodontium destruction

  18. [Clinical study of glycated albumin measurement by enzymatic method in type 2 diabetes mellitus].

    Science.gov (United States)

    Ba, Jian-Ming; Dou, Jing-Tao; Zhang, Xiao-Qun; Ma, Fang-Ling; Zhai, Huai-Wei; Zou, Xiao-Man; Mu, Yi-Ming; Lu, Ju-Ming

    2009-06-09

    To evaluate the clinical significance of glycated albumin (GA) measured by enzymatic method and to compare its effect with glycosylated hemoglobin A1c (HbA1c) in type 2 diabetes mellitus (DM). 128 type 2 DM patients and 84 normal subjects from the Chinese PLA General Hospital were enrolled for the study. The levels of GA, HbA1c, FBG, PBG in DM patient were detected at baseline and followed visit at 2, 4, 8 weeks after blood glucose management. The levels of GA, HbA1c, FBG, PBG and 75 g OGTT were also detected in above normal subjects. Intra CV and inter CV of enzymatic were (0.74-0.9)% and (0.94-1.49)% respectively. In normal subjects GA was in the range of (9-14)%. At baseline, the GA level was significantly correlated with HbA1c (r = 0.8326, P PBG. After 2, 4, 8 weeks treatment, GA level in DM patients was concomitantly decreased with the improvement of FBG, PBG and HbA1c. At early 2 weeks visit, GA, but not HbA1c, showed significant decrease from its baseline (P PBG during the 8 weeks treatment. GA was more sensitive than HbA1c for short-term variations of glycemic control during treatment of diabetic patients. GA can be used as a better index of short term mean level of blood glucose in diabetic patients.

  19. Advanced glycation end products: a link between periodontitis and diabetes mellitus?

    Science.gov (United States)

    Gurav, Abhijit N

    2013-09-01

    Advanced glycation end products (AGEs) are synthesized via the non enzymaticglycation and oxidation of proteins, lipids and nucleic acids. The production of AGEs is particularly enhanced in chronic hyperglycemia, as in diabetes mellitus (DM). The formation of irreversible AGEs affects the tissues by compromising the physiologic and mechanical functions, as a result of defective constitution of the extracellular matrix (ECM) components. Periodontitis is an inflammatory disease of microbial origin, resulting in devastation of the tooth supporting apparatus. This disease condition has severe implicationsin subjects with DM, since the tooth supporting tissuescontain ECM targeted by AGE. There is miniscule literature regarding the contribution of AGE to periodontal disease in patients with DM. The purpose of this review is to address the prejudicial role of AGEs in relation to various tissue components. This paper is an attempt to elucidatethe possible link of AGEs between periodontitis and DM. The exploration of novel therapeutic strategies to target AGEs for the treatment of periodontitis in DM subjects is certainly intriguing.

  20. K88 Fimbrial Adhesin Targeting of Microspheres Containing Gentamicin Made with Albumin Glycated with Lactose

    Science.gov (United States)

    Sarabia-Sainz, Andre-i; Sarabia-Sainz, Hector Manuel; Ramos-Clamont Montfort, Gabriela; Mata-Haro, Veronica; Guzman-Partida, Ana María; Guzman, Roberto; Garcia-Soto, Mariano; Vazquez-Moreno, Luz

    2015-01-01

    The formulation and characterization of gentamicin-loaded microspheres as a delivery system targeting enterotoxigenic Escherichia coli K88 (E. coli K88) was investigated. Glycated albumin with lactose (BSA-glucose-β (4-1) galactose) was used as the microsphere matrix (MS-Lac) and gentamicin included as the transported antibiotic. The proposed target strategy was that exposed galactoses of MS-Lac could be specifically recognized by E. coli K88 adhesins, and the delivery of gentamicin would inhibit bacterial growth. Lactosylated microspheres (MS-Lac1, MS-Lac2 and MS-Lac3) were obtained using a water-in-oil emulsion, containing gentamicin, followed by crosslinking with different concentrations of glutaraldehyde. Electron microscopy displayed spherical particles with a mean size of 10–17 µm. In vitro release of gentamicin from MS-Lac was best fitted to a first order model, and the antibacterial activity of encapsulated and free gentamicin was comparable. MS-Lac treatments were recognized by plant galactose-specific lectins from Ricinus communis and Sophora japonica and by E. coli K88 adhesins. Results indicate MS-Lac1, produced with 4.2 mg/mL of crosslinker, as the best treatment and that lactosylated microsphere are promising platforms to obtain an active, targeted system against E. coli K88 infections. PMID:26389896