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Sample records for binding previous studies

  1. Radon anomalies prior to earthquakes (1). Review of previous studies

    International Nuclear Information System (INIS)

    Ishikawa, Tetsuo; Tokonami, Shinji; Yasuoka, Yumi; Shinogi, Masaki; Nagahama, Hiroyuki; Omori, Yasutaka; Kawada, Yusuke

    2008-01-01

    The relationship between radon anomalies and earthquakes has been studied for more than 30 years. However, most of the studies dealt with radon in soil gas or in groundwater. Before the 1995 Hyogoken-Nanbu earthquake, an anomalous increase of atmospheric radon was observed at Kobe Pharmaceutical University. The increase was well fitted with a mathematical model related to earthquake fault dynamics. This paper reports the significance of this observation, reviewing previous studies on radon anomaly before earthquakes. Groundwater/soil radon measurements for earthquake prediction began in 1970's in Japan as well as foreign countries. One of the most famous studies in Japan is groundwater radon anomaly before the 1978 Izu-Oshima-kinkai earthquake. We have recognized the significance of radon in earthquake prediction research, but recently its limitation was also pointed out. Some researchers are looking for a better indicator for precursors; simultaneous measurements of radon and other gases are new trials in recent studies. Contrary to soil/groundwater radon, we have not paid much attention to atmospheric radon before earthquakes. However, it might be possible to detect precursors in atmospheric radon before a large earthquake. In the next issues, we will discuss the details of the anomalous atmospheric radon data observed before the Hyogoken-Nanbu earthquake. (author)

  2. New study reveals twice as many asteroids as previously believed

    Science.gov (United States)

    2002-05-01

    The ISO satellite Credits: ESA ISO An artist's impression of the ISO spacecraft. The ISO Deep Asteroid Search indicates that there are between 1.1 million and 1.9 million 'space rocks' larger than 1 kilometre in diameter in the so-called 'main asteroid belt', about twice as many as previously believed. However, astronomers think it is premature to revise current assessments of the risk of the Earth being hit by an asteroid. Despite being in our own Solar System, asteroids can be more difficult to study than very distant galaxies. With sizes of up to one thousand kilometres in diameter, the brightness of these rocky objects may vary considerably in just a few minutes. They move very quickly with respect to the stars - they have been dubbed 'vermin of the sky' because they often appear as trails on long exposure images. This elusiveness explains why their actual number and size distribution remains uncertain. Most of the almost 40,000 asteroids catalogued so far (1) orbit the Sun forming the 'main asteroid belt', between Mars and Jupiter, too far to pose any threat to Earth. However, space-watchers do keep a closer eye on another category of asteroids, the 'Near Earth Asteroids' or 'NEAs', which are those whose orbits cross, or are likely to cross, that of our planet. The ISO Deep Asteroid Search (IDAS), the first systematic search for these objects performed in infrared light, focused on main belt asteroids. Because it is impossible to simply point the telescope at the whole main belt and count, astronomers choose selected regions of the belt and then use a theoretical model to extrapolate the data to the whole belt. Edward Tedesco (TerraSystems, Inc., New Hampshire, United States) and François-Xavier Desert (Observatoire de Grenoble, France) observed their main belt selected areas in 1996 and 1997 with ESA's ISO. They found that in the middle region of the belt the density of asteroids was 160 asteroids larger than 1 kilometre per square degree - an area of the

  3. DNA binding studies of tartrazine food additive.

    Science.gov (United States)

    Kashanian, Soheila; Zeidali, Sahar Heidary

    2011-07-01

    The interaction of native calf thymus DNA with tartrazine in 10 mM Tris-HCl aqueous solution at neutral pH 7.4 was investigated. Tartrazine is a nitrous derivative and may cause allergic reactions, with a potential of toxicological risk. Also, tartrazine induces oxidative stress and DNA damage. Its DNA binding properties were studied by UV-vis and circular dichroism spectra, competitive binding with Hoechst 33258, and viscosity measurements. Tartrazine molecules bind to DNA via groove mode as illustrated by hyperchromism in the UV absorption band of tartrazine, decrease in Hoechst-DNA solution fluorescence, unchanged viscosity of DNA, and conformational changes such as conversion from B-like to C-like in the circular dichroism spectra of DNA. The binding constants (K(b)) of DNA with tartrazine were calculated at different temperatures. Enthalpy and entropy changes were calculated to be +37 and +213 kJ mol(-1), respectively, according to the Van't Hoff equation, which indicated that the reaction is predominantly entropically driven. Also, tartrazine does not cleave plasmid DNA. Tartrazine interacts with calf thymus DNA via a groove interaction mode with an intrinsic binding constant of 3.75 × 10(4) M(-1).

  4. Studies of Fibronectin-Binding Proteins of Streptococcus equi

    OpenAIRE

    Lannergård, Jonas; Flock, Margareta; Johansson, Staffan; Flock, Jan-Ingmar; Guss, Bengt

    2005-01-01

    Streptococcus equi subsp. equi is the causative agent of strangles, a disease of the upper respiratory tract in horses. The initiation of S. equi subsp. equi infection is likely to involve cell surface-anchored molecules mediating bacterial adhesion to the epithelium of the host. The present study describes the cloning and characterization of FNEB, a fibronectin-binding protein with cell wall-anchoring motifs. FNEB can thus be predicted as cell surface located, contrary to the two previously ...

  5. 40 CFR 152.93 - Citation of a previously submitted valid study.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Citation of a previously submitted... Data Submitters' Rights § 152.93 Citation of a previously submitted valid study. An applicant may... the citation is necessary. (b) Study previously submitted by another person. If the applicant is not...

  6. Summary of Previous Chamber or Controlled Anthrax Studies and Recommendations for Possible Additional Studies

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.; Amidan, Brett G.; Morrow, Jayne B.

    2010-12-29

    This report and an associated Excel file(a) summarizes the investigations and results of previous chamber and controlled studies(b) to characterize the performance of methods for collecting, storing and/or transporting, extracting, and analyzing samples from surfaces contaminated by Bacillus anthracis (BA) or related simulants. This report and the Excel are the joint work of the Pacific Northwest National Laboratory (PNNL) and the National Institute of Standards and Technology (NIST) for the Department of Homeland Security, Science and Technology Directorate. The report was originally released as PNNL-SA-69338, Rev. 0 in November 2009 with limited distribution, but was subsequently cleared for release with unlimited distribution in this Rev. 1. Only minor changes were made to Rev. 0 to yield Rev. 1. A more substantial update (including summarizing data from other studies and more condensed summary tables of data) is underway

  7. Preliminary studies of 99mTc-PQQ-NMDAR binding and effect of specificity binding by mannitol

    International Nuclear Information System (INIS)

    Xingqin Zhou; Yanyan Kong; Guoxian Cao; Jiankang Zhang

    2013-01-01

    Pyrroloquinoline quinone (PQQ) is a powerful neuroprotectant that specifically binds to brain NMDA receptors and inhibits excitotoxicity. Imaging this binding reaction in the brain remains a long sought goal in this field of study, and one of the primary challenges remaining is enabling soluble labeled PQQ to pass the blood-brain barrier (BBB). Previously, our group successfully labeled PQQ with Technetium-99m ( 99m Tc), a metastable nuclear isomer used in radioactive isotope medical tests. In this work, we determined the specific binding of 99m Tc-PQQ and NMDAR by radioligand receptor assay. Ebselen (EB) and MK-801 both effectively inhibited 99m Tc-PQQ binding. We then investigated methods of opening the BBB using mannitol to enable entry to the brain by 99m Tc-PQQ. Our results showed that 7.5 mL/kg of 20 % mannitol effectively opened the BBB and 20 min was the optimum treatment time. Competition studies showed that mannitol did not affect the specific binding between 99m Tc-PQQ and NMDA receptors. Using this method, the amount of 99m Tc-PQQ uptake and retention was increased most significantly in the hippocampus and cortex, and re-opening the BBB did not affect binding. Together, our results demonstrate that the use of mannitol to open the BBB may contribute significantly to improving image quality by increasing the uptake amount of a water-soluble agent in brain. (author)

  8. Identification of multidrug resistance in previously treated tuberculosis patients: a mixed methods study in Cambodia

    Science.gov (United States)

    Royce, S; Khann, S; Yadav, RP; Mao, ET; Cattamanchi, A; Sam, S; Handley, MA

    2014-01-01

    SUMMARY Setting Previously treated tuberculosis (TB) patients are a priority for drug susceptibility testing (DST) to identify cases with multidrug resistance (MDR). In Cambodia, a recent study found that only one-third of smear-positive previously treated patients had DST results. Objective To quantify the gaps in detecting MDR in previously treated TB patients in Cambodia, and describe health workers’ perspectives on barriers, facilitators and potential interventions. Design We analyzed case notifications in Cambodia (2004–2012) and conducted semi-structured interviews with key stakeholders Results The proportion of previously treated notifications varied significantly across provinces 2010–12, in the context of longer term trends of decreasing relapse and increasing “other” retreatment notifications. Correct classification of patients’ TB treatment history and ensuring specimens from previously-treated patients are collected and reach the laboratory could nearly double the number of detected MDR-TB cases. Identified barriers include patients’ reluctance to disclose and staff difficulty eliciting treatment history, partly due to availability of streptomycin only in hospitals. Facilitators include trained health workers, collection of sputum for DST even if previously treated patients are not taking streptomycin, streamlining sputum transportation and promptly reporting results. Conclusion Improved monitoring, supportive supervision, and correctly classifying previously treated patients are essential for improving detection of MDR-TB. PMID:25299861

  9. Matched cohort study of external cephalic version in women with previous cesarean delivery.

    Science.gov (United States)

    Keepanasseril, Anish; Anand, Keerthana; Soundara Raghavan, Subrahmanian

    2017-07-01

    To evaluate the efficacy and safety of external cephalic version (ECV) among women with previous cesarean delivery. A retrospective study was conducted using data for women with previous cesarean delivery and breech presentation who underwent ECV at or after 36 weeks of pregnancy during 2011-2016. For every case, two multiparous women without previous cesarean delivery who underwent ECV and were matched for age and pregnancy duration were included. Characteristics and outcomes were compared between groups. ECV was successful for 32 (84.2%) of 38 women with previous cesarean delivery and 62 (81.6%) in the control group (P=0.728). Multivariate regression analysis confirmed that previous cesarean was not associated with ECV success (odds ratio 1.89, 95% confidence interval 0.19-18.47; P=0.244). Successful vaginal delivery after successful ECV was reported for 19 (59.4%) women in the previous cesarean delivery group and 52 (83.9%) in the control group (Pcesarean delivery. To avoid a repeat cesarean delivery, ECV can be offered to women with breech presentation and previous cesarean delivery who are otherwise eligible for a trial of labor. © 2017 International Federation of Gynecology and Obstetrics.

  10. Binding of [3H]mazindol to cardiac norepinephrine transporters: kinetic and equilibrium studies.

    Science.gov (United States)

    Raffel, David M; Chen, Wei

    2004-07-01

    The norepinephrine transporter (NET) is the carrier that drives the neuronal norepinephrine uptake mechanism (uptake1) in mammalian hearts. The radioligand [3H]mazindol binds with high affinity to NET. In this study, the kinetics of [3H]mazindol binding to NET were measured using a rat heart membrane preparation. Results from these studies were used to set up saturation binding assays designed to measure cardiac NET densities (Bmax) and competitive inhibition assays designed to measure inhibitor binding affinities (KI) for NET. Saturation binding assays measured NET densities in rat, rabbit, and canine hearts. Assay reproducibility was assessed and the effect of NaCl concentration on [3H]mazindol binding to NET was studied using membranes from rat and canine hearts. Specificity of [3H]mazindol binding to NET was determined in experiments in which the neurotoxin 6-hydroxydopamine (6-OHDA) was used to selectively destroy cardiac sympathetic nerve terminals in rats. Competitive inhibition studies measured KI values for several NET inhibitors and substrates. In kinetic studies using rat heart membranes, [3H]mazindol exhibited a dissociation rate constant koff=0.0123+/-0.0007 min(-1) and an association rate constant kon=0.0249+/-0.0019 nM(-1)min(-1). In saturation binding assays, [3H]mazindol binding was monophasic and saturable in all cases. Increasing the concentration of NaCl in the assay buffer increased binding affinity significantly, while only modestly increasing Bmax. Injections of 6-OHDA in rats decreased measured cardiac NET Bmax values in a dose-dependent manner, verifying that [3H]mazindol binds specifically to NET from sympathetic nerve terminals. Competitive inhibition studies provided NET inhibitor and substrate KI values consistent with previously reported values. These studies demonstrate the high selectivity of [3H]mazindol binding for the norepinephrine transporter in membrane preparations from mammalian hearts.

  11. Developing Reading Comprehension through Metacognitive Strategies: A Review of Previous Studies

    Science.gov (United States)

    Channa, Mansoor Ahmed; Nordin, Zaimuariffudin Shukri; Siming, Insaf Ali; Chandio, Ali Asgher; Koondher, Mansoor Ali

    2015-01-01

    This paper has reviewed the previous studies on metacognitive strategies based on planning, monitoring, and evaluating in order to develop reading comprehension. The main purpose of this review in metacognition, and reading domain is to help readers to enhance their capabilities and power reading through these strategies. The researchers reviewed…

  12. Study of some physical aspects previous to design of an exponential experiment

    International Nuclear Information System (INIS)

    Caro, R.; Francisco, J. L. de

    1961-01-01

    This report presents the theoretical study of some physical aspects previous to the design of an exponential facility. The are: Fast and slow flux distribution in the multiplicative medium and in the thermal column, slowing down in the thermal column, geometrical distribution and minimum needed intensity of sources access channels and perturbations produced by possible variations in its position and intensity. (Author) 4 refs

  13. Study of functional-performance deficits in athletes with previous ankle sprains

    Directory of Open Access Journals (Sweden)

    hamid Babaee

    2008-04-01

    Full Text Available Abstract Background: Despite the importance of functional-performance deficits in athletes with history of ankle sprain few, studies have been carried out in this area. The aim of this research was to study relationship between previous ankle sprains and functional-performance deficits in athletes. Materials and methods: The subjects were 40 professional athletes selected through random sampling among volunteer participants in soccer, basketball, volleyball and handball teams of Lorestan province. The subjects were divided into 2 groups: Injured group (athletes with previous ankle sprains and healthy group (athletes without previous ankle sprains. In this descriptive study we used Functional-performance tests (figure 8 hop test and side hop test to determine ankle deficits and limitations. They participated in figure 8 hop test including hopping in 8 shape course with the length of 5 meters and side hop test including 10 side hop repetitions in course with the length of 30 centimeters. Time were recorded via stopwatch. Results: After data gathering and assessing information distributions, Pearson correlation was used to assess relationships, and independent T test to assess differences between variables. Finally the results showed that there is a significant relationship between previous ankle sprains and functional-performance deficits in the athletes. Conclusion: The athletes who had previous ankle sprains indicated functional-performance deficits more than healthy athletes in completion of mentioned functional-performance tests. The functional-performance tests (figure 8 hop test and side hop test are sensitive and suitable to assess and detect functional-performance deficits in athletes. Therefore we can use the figure 8 hop and side hop tests for goals such as prevention, assessment and rehabilitation of ankle sprains without spending too much money and time.

  14. Previous treatment influences fingolimod efficacy in relapsing-remitting multiple sclerosis: results from an observational study.

    Science.gov (United States)

    Baldi, Eleonora; Guareschi, Angelica; Vitetta, Francesca; Senesi, Caterina; Curti, Erica; Montepietra, Sara; Simone, Anna Maria; Immovilli, Paolo; Caniatti, Luisa; Tola, Maria Rosaria; Pesci, Ilaria; Montanari, Enrico; Sola, Patrizia; Granella, Franco; Motti, Luisa; Ferraro, Diana

    2014-09-01

    Fingolimod (FTY) is licensed as a disease-modifying treatment in highly active relapsing-remitting multiple sclerosis. The aim of the study was to evaluate the efficacy and safety of FTY in a real-life setting and to explore the possible role of clinical and MRI parameters, including previous treatment type, in predicting its efficacy. Clinical and MRI data was collected on 127 patients assigned to treatment with FTY in six multiple sclerosis centers in Emilia-Romagna, Italy, between August 2011 and June 2013. During a mean follow-up period of 10 months (range 1-22), we observed a total of 47 relapses in 39 patients (30.7%); new T2 lesions or gadolinium-enhancing (Gd+) lesions were present at follow-up MRI in 32/71 patients (45%). Expanded disability status scale (EDSS) at the end of the follow-up period was not different when compared to the baseline EDSS. Serious adverse events occurred in three patients (2.4%). A higher proportion of patients previously treated with natalizumab showed clinical (41%) or MRI activity (54%). Previous treatment with natalizumab increased the risk of a relapse within 30 days (versus immunomodulatory drugs; OR: 4.3; p = 0.011) and at survival analysis (versus remaining patients; HR: 1.9; p = 0.046). Study limitations include a small population sample, a short observation period with variable timing of follow-up MRI and different baseline characteristics of patients previously treated with natalizumab compared to those treated with immunomodulatory drugs. This study confirms the efficacy of FTY in reducing relapse rate in patients previously treated with immunomodulatory drugs, while it seems to be less effective in patients discontinuing natalizumab. Due to the short duration of follow-up it is not possible to evaluate disability progression; however, no difference was observed between the groups.

  15. Previous infection and the risk of ischaemic stroke in Italy: the IN2 study.

    Science.gov (United States)

    Consoli, D; Vidale, S; Aguglia, U; Bassi, P; Cavallini, A; Galati, F; Guidetti, D; Marcello, N; Micieli, G; Pracucci, G; Rasura, M; Siniscalchi, A; Sterzi, R; Toni, D; Inzitari, D

    2015-03-01

    There is an increasing interest in new risk factors for ischaemic stroke. Acute and chronic infections could contribute to different aetiological mechanisms of atherosclerosis that lead to cerebrovascular disease. The aim of this study was to investigate the hypothesis that previous infections and Chlamydia pneumoniae in particular increase the risk of ischaemic stroke in the population. This was a prospective case-control study involving 11 Italian stroke units. Controls were age- and sex-matched with cases, represented by patients admitted to hospital for acute ischaemic stroke. For each participant classical vascular risk factors and previous inflammatory and infectious events up to 1 month before were registered. Blood samples were collected to analyse inflammatory markers and titres of antibodies against C. pneumoniae. A total of 1002 participants were included (mean age 69 years) with 749 ischaemic stroke patients. Infections occurred within 1 month previously in 12% of the entire sample with a higher prevalence in the case group (14.4% vs. 3.9%). At multivariate analysis of the seropositivity of IgA antibodies against C. pneumoniae increased the risk of stroke significantly (relative risk 2.121; 95% confidence interval 1.255-3.584) and an early previous infection (up to 7 days before the event) contributed to a rise in probability of acute cerebral ischaemia (relative risk 3.692; 95% confidence interval 1.134-6.875). Early previous infections and persistent chronic infection of C. pneumoniae could contribute to increase the risk of ischaemic stroke significantly, in the elderly especially. © 2014 EAN.

  16. Fluorescence spectroscopic studies on binding of a flavonoid ...

    Indian Academy of Sciences (India)

    Binding of quercetin to human serum albumin (HSA) was studied and the binding constant measured by following the red-shifted absorption spectrum of quercetin in the presence of HSA and the quenching of the intrinsic protein fluorescence in the presence of different concentrations of quercetin. Fluorescence lifetime ...

  17. HIV-related neuropsychological impairment in patients with previous substance use: A preliminary study

    OpenAIRE

    García-Torres, Amalia; Vergara-Moragues, Esperanza (UNIR); Piñón-Blanco, Adolfo; Pérez-García, Miguel

    2015-01-01

    Human immunodeficiency virus (HIV) can result in cognitive disorders that significantly interfere with the daily activities of HIV patients. These disorders may be worse when there is a history of psychoactive substance use. Our objective is to assess the neuropsychological profile in a group of HIV patients with previous drug use compared to a group of HIV-negative patients with a history of drug use. The study included a total of 28 Spanish adult subjects, of which 14 were HIV-infected and ...

  18. Data from studies of previous radioactive waste disposal in Massachusetts Bay

    International Nuclear Information System (INIS)

    Curtis, W.R.; Mardis, H.M.

    1984-12-01

    This report presents the results of studies conducted in Massachusetts Bay during 1981 and 1982. Included are data from: (1) a side scan sonar survey of disposal areas in the Bay that was carried out by the National Oceanic and Atmospheric Administration (NOAA) for EPA; (2) Collections of sediment and biota by NOAA for radiochemical analysis by EPA; (3) collections of marketplace seafood samples by the Food and Drug Administration (FDA) for radioanalysis by both FDA and EPA; and (4) a radiological monitoring survey of LLW disposal areas by EPA to determine whether there should be any concern for public health resulting from previous LLW disposals in the Bay

  19. Cystic echinococcosis in Jordan: A review of causative species, previous studies, serological and radiological diagnosis.

    Science.gov (United States)

    Hijjawi, Nawal S; Al-Radaideh, Ali M; Rababah, Eman M; Al-Qaoud, Khaled M; Bani-Hani, Kamal E

    2018-03-01

    Cystic echinococcosis (CE)/hydatidosis is a zoonotic disease which occur in human and herbivore animals as a result of infection with the larval stage of the taeniid cestode Echinococcus granulosus sensu lato (s. l.). In human, CE is a serious public health concern in many parts of the world including Jordan. The present review will cover CE causative agent: E. granulosus species/genotypes; life cycle of E. granulosus parasite, all published previous studies on CE in Jordan (humans, intermediate hosts, definitive host) as well as its diagnostic methods in human. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Does the previous diagnosis of arterial hypertension affect one's daily life? Pro-Saude Study.

    Science.gov (United States)

    Goffredo Filho, Gilberto Senechal de; Lopes, Claudia de Souza; Faerstein, Eduardo

    2013-12-01

    In addition to damaging several target organs, arterial hypertension may negatively impact patients' activities of daily living. Biological and behavioral mechanisms underlying such limitations have yet to be clarified. The objectives of this study were to investigate whether having been previously told of a hypertension diagnosis is associated with the frequency and duration of temporary limitations in activities of daily living, and whether these relationships differ by gender, age, or socioeconomic position. We analyzed sectional data from 2,666 participants (56% women; 55% with high school or lower schooling) at the baseline phase (1999 - 2001) of a longitudinal investigation of university employees in Rio de Janeiro, Brazil (Pró-Saúde Study), asking participants whether they had ever been diagnosed with hypertension by a health professional, if they had been unable to perform any activities of daily living due to a health problem in the previous 2 weeks, and for how many days that had occurred. Multinomial logistic regression models were fitted for the overall study population and for age, gender, educational level, and per capita household income strata. Associations between hypertension diagnosis and temporary limitations were not observed in the overall study population and in gender, education and income strata. However, there were higher odds of temporary limitations among participants aged 55 years old or more with hypertension diagnosis (adjusted OR = 9.5; 95%CI 1.5 - 58.6), regardless of blood pressure levels and use of antihypertensive medication. Elderly people may keep an attitude of higher vigilance regarding conditions or events potentially worsening their health status.

  1. Cytotoxic, DNA binding, DNA cleavage and antibacterial studies of ...

    Indian Academy of Sciences (India)

    fluoroquinolone complexes. Mohan N ... DNA-binding properties of Ru complexes have been studied by means of absorption spectrophotometry and viscosity measurements as well as their HS DNA cleavage properties by means of agarose gel ...

  2. A longitudinal study of plasma insulin and glucagon in women with previous gestational diabetes

    DEFF Research Database (Denmark)

    Damm, P; Kühl, C; Hornnes, P

    1995-01-01

    OBJECTIVE: To investigate whether plasma insulin or glucagon predicts later development of diabetes in women with gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: The subjects studied were 91 women with diet-treated GDM and 33 healthy women. Plasma insulin and glucagon during a 50...... at follow-up (2 had insulin-dependent diabetes mellitus, 13 had non-insulin-dependent diabetes mellitus, and 12 had impaired glucose tolerance). Compared with the control subjects, women with previous GDM had relatively impaired insulin secretion (decreased insulinogenic index and delayed peak insulin...... for subsequent development of overt diabetes (logistic regression analysis). CONCLUSIONS: Women who develop GDM have a relative insulin secretion deficiency, the severity of which is predictive for later development of diabetes. Furthermore, our data indicate that their relatively reduced beta-cell function may...

  3. Case-control study for colorectal cancer genetic susceptibility in EPICOLON: previously identified variants and mucins

    International Nuclear Information System (INIS)

    Abulí, Anna; Morillas, Juan D; Rigau, Joaquim; Latorre, Mercedes; Fernández-Bañares, Fernando; Peña, Elena; Riestra, Sabino; Payá, Artemio; Jover, Rodrigo; Xicola, Rosa M; Llor, Xavier; Fernández-Rozadilla, Ceres; Carvajal-Carmona, Luis; Villanueva, Cristina M; Moreno, Victor; Piqué, Josep M; Carracedo, Angel; Castells, Antoni; Andreu, Montserrat; Ruiz-Ponte, Clara; Castellví-Bel, Sergi; Alonso-Espinaco, Virginia; Muñoz, Jenifer; Gonzalo, Victoria; Bessa, Xavier; González, Dolors; Clofent, Joan; Cubiella, Joaquin

    2011-01-01

    Colorectal cancer (CRC) is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase) are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category) and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium. CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family. None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value < 0.05 in EPICOLON stage 1 [rs698 in ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive), rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive), rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant), and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive). In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1.12, 95% CI = 1

  4. Case-control study for colorectal cancer genetic susceptibility in EPICOLON: previously identified variants and mucins

    Directory of Open Access Journals (Sweden)

    Moreno Victor

    2011-08-01

    Full Text Available Abstract Background Colorectal cancer (CRC is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium. Methods CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family. Results None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive, rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive, rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant, and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive. In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1

  5. Inhibition of [(11)C]mirtazapine binding by alpha(2)-adrenoceptor antagonists studied by positron emission tomography in living porcine brain

    DEFF Research Database (Denmark)

    Smith, Donald F.; Dyve, Suzan; Minuzzi, Luciano

    2006-01-01

    We have developed [(11)C]mirtazapine as a ligand for PET studies of antidepressant binding in living brain. However, previous studies have determined neither optimal methods for quantification of [(11)C]mirtazapine binding nor the pharmacological identity of this binding. To obtain that informati...

  6. Trends in the Binding of Cell Penetrating Peptides to siRNA: A Molecular Docking Study

    Directory of Open Access Journals (Sweden)

    P. V. G. M. Rathnayake

    2017-01-01

    Full Text Available The use of gene therapeutics, including short interfering RNA (siRNA, is limited by the lack of efficient delivery systems. An appealing approach to deliver gene therapeutics involves noncovalent complexation with cell penetrating peptides (CPPs which are able to penetrate the cell membranes of mammals. Although a number of CPPs have been discovered, our understanding of their complexation and translocation of siRNA is as yet insufficient. Here, we report on computational studies comparing the binding affinities of CPPs with siRNA, considering a variety of CPPs. Specifically, seventeen CPPs from three different categories, cationic, amphipathic, and hydrophobic CPPs, were studied. Molecular mechanics were used to minimize structures, while molecular docking calculations were used to predict the orientation and favorability of sequentially binding multiple peptides to siRNA. Binding scores from docking calculations were highest for amphipathic peptides over cationic and hydrophobic peptides. Results indicate that initial complexation of peptides will likely occur along the major groove of the siRNA, driven by electrostatic interactions. Subsequent binding of CPPs is likely to occur in the minor groove and later on bind randomly, to siRNA or previously bound CPPs, through hydrophobic interactions. However, hydrophobic CPPs do not show this binding pattern. Ultimately binding yields a positively charged nanoparticle capable of noninvasive cellular import of therapeutic molecules.

  7. A study about the interest and previous contact of high school students with Astronomy

    Science.gov (United States)

    Carvalho, C. L.; Zanitti, M. H. R.; Felicidade, B. L.; Gomes, A. D. T.; Dias, E. W.; Coelho, F. O.

    2016-04-01

    The currently problems in Astronomy teaching in Brazilian Basic Education contrast with the space, and the popularity that astronomical themes have in various media in the country. In this work, we present the results of a study about the interest, and previous contact of high school students from a public school in the city of "São João del-Rei"/MG with topics related to Astronomy. The study and the pedagogical intervention were carried out by students of the PIBID/CAPES/UFSJ. The intervention was performed through an oral exposition with the students' participation, followed by the use of the Stellarium program. The results suggest the majority of students surveyed are interested in Astronomy, and have had some contact with the area. However, some inconsistencies in their responses were identified and examined. The implications for research and for Astronomy Education are discussed. We also make some considerations about relationship between the lack of specific knowledge and the misinformation as one possible reason for the little interest of students in various areas of Science.

  8. Biosystematic studies on Dactylis L. l. Review of the previous studies. 1.2. Cytology, genetics, experimental studies, and evolution

    Directory of Open Access Journals (Sweden)

    Marta Mizianty

    2014-01-01

    Full Text Available In this paper the author presents a review of the previous studies on Dactylis L., dealing with cytology,genetics, experimental studies and evolution. Following cytotypes of Dactylis are distributed mostly in Central Europe: 16 diploids, 7 tetraploids and also 2 hexaploids in North Africa. Some aneuploids and accessory chromosomes were also found in this genus. Data dealing with karyotypes of some taxa, and geographical distribution of cytotypes are also listed. Selected problems concerning crossing within diploids as well as tetraploids and also between diploids and teraploids were presented. Some opinions regarding the evolution in the genus Dactylis were also demonstrated. In all these hypotheses the following diploids are considered to be the oldest: D. smithii Link subsp. smithii, D. g. subsp. aschersoniana (Greabn. Thell. and D. g. subsp. himalayensis Dom.

  9. Seeking for Non-Zinc-Binding MMP-2 Inhibitors: Synthesis, Biological Evaluation and Molecular Modelling Studies

    Directory of Open Access Journals (Sweden)

    Alessandra Ammazzalorso

    2016-10-01

    Full Text Available Matrix metalloproteinases (MMPs are an important family of zinc-containing enzymes with a central role in many physiological and pathological processes. Although several MMP inhibitors have been synthesized over the years, none reached the market because of off-target effects, due to the presence of a zinc binding group in the inhibitor structure. To overcome this problem non-zinc-binding inhibitors (NZIs have been recently designed. In a previous article, a virtual screening campaign identified some hydroxynaphtyridine and hydroxyquinoline as MMP-2 non-zinc-binding inhibitors. In the present work, simplified analogues of previously-identified hits have been synthesized and tested in enzyme inhibition assays. Docking and molecular dynamics studies were carried out to rationalize the activity data.

  10. The biomechanics of running in athletes with previous hamstring injury: A case-control study.

    Science.gov (United States)

    Daly, C; Persson, U McCarthy; Twycross-Lewis, R; Woledge, R C; Morrissey, D

    2016-04-01

    Hamstring injury is prevalent with persistently high reinjury rates. We aim to inform hamstring rehabilitation by exploring the electromyographic and kinematic characteristics of running in athletes with previous hamstring injury. Nine elite male Gaelic games athletes who had returned to sport after hamstring injury and eight closely matched controls sprinted while lower limb kinematics and muscle activity of the previously injured biceps femoris, bilateral gluteus maximus, lumbar erector spinae, rectus femoris, and external oblique were recorded. Intergroup comparisons of muscle activation ratios and kinematics were performed. Previously injured athletes demonstrated significantly reduced biceps femoris muscle activation ratios with respect to ipsilateral gluteus maximus (maximum difference -12.5%, P = 0.03), ipsilateral erector spinae (maximum difference -12.5%, P = 0.01), ipsilateral external oblique (maximum difference -23%, P = 0.01), and contralateral rectus femoris (maximum difference -22%, P = 0.02) in the late swing phase. We also detected sagittal asymmetry in hip flexion (maximum 8°, P = 0.01), pelvic tilt (maximum 4°, P = 0.02), and medial rotation of the knee (maximum 6°, P = 0.03) effectively putting the hamstrings in a lengthened position just before heel strike. Previous hamstring injury is associated with altered biceps femoris associated muscle activity and potentially injurious kinematics. These deficits should be considered and addressed during rehabilitation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Curcumin Binding to Beta Amyloid: A Computational Study.

    Science.gov (United States)

    Rao, Praveen P N; Mohamed, Tarek; Teckwani, Karan; Tin, Gary

    2015-10-01

    Curcumin, a chemical constituent present in the spice turmeric, is known to prevent the aggregation of amyloid peptide implicated in the pathophysiology of Alzheimer's disease. While curcumin is known to bind directly to various amyloid aggregates, no systematic investigations have been carried out to understand its ability to bind to the amyloid aggregates including oligomers and fibrils. In this study, we constructed computational models of (i) Aβ hexapeptide (16) KLVFFA(21) octamer steric-zipper β-sheet assembly and (ii) full-length Aβ fibril β-sheet assembly. Curcumin binding in these models was evaluated by molecular docking and molecular dynamics (MD) simulation studies. In both the models, curcumin was oriented in a linear extended conformation parallel to fiber axis and exhibited better stability in the Aβ hexapeptide (16) KLVFFA(21) octamer steric-zipper model (Ebinding  = -10.05 kcal/mol) compared to full-length Aβ fibril model (Ebinding  = -3.47 kcal/mol). Analysis of MD trajectories of curcumin bound to full-length Aβ fibril shows good stability with minimum Cα-atom RMSD shifts. Interestingly, curcumin binding led to marked fluctuations in the (14) HQKLVFFA(21) region that constitute the fibril spine with RMSF values ranging from 1.4 to 3.6 Å. These results show that curcumin binding to Aβ shifts the equilibrium in the aggregation pathway by promoting the formation of non-toxic aggregates. © 2015 John Wiley & Sons A/S.

  12. Covalent binding of aniline to humic substances. 1. Kinetic studies

    Science.gov (United States)

    Weber, E.J.; Spidle, D.L.; Thorn, K.A.

    1996-01-01

    The reaction kinetics for the covalent binding of aniline with reconstituted IHSS humic and fulvic acids, unfractionated DOM isolated from Suwannee River water, and whole samples of Suwannee River water have been investigated. The reaction kinetics in each of these systems can be adequately described by a simple second-order rate expression. The effect of varying the initial concentration of aniline on reaction kinetics suggested that approximately 10% of the covalent binding sites associated with Suwannee River fulvic acid are highly reactive sites that are quickly saturated. Based on the kinetic parameters determined for the binding of aniline with the Suwannee River fulvic and humic acid isolates, it was estimated that 50% of the aniline concentration decrease in a Suwannee River water sample could be attributed to reaction with the fulvic and humic acid components of the whole water sample. Studies with Suwannee River fulvic acid demonstrated that the rate of binding decreased with decreasing pH, which parallels the decrease in the effective concentration of the neutral form, or reactive nucleophilic species of aniline. The covalent binding of aniline with Suwannee River fulvic acid was inhibited by prior treatment of the fulvic acid with hydrogen sulfide, sodium borohydride, or hydroxylamine. These observations are consistent with a reaction pathway involving nucleophilic addition of aniline to carbonyl moieties present in the fulvic acid.

  13. Rancidity inhibition study in frozen whole mackerel (scomber scombrus by a previous plant extract treatment.

    Directory of Open Access Journals (Sweden)

    Aubourg, Santiago P.

    2005-09-01

    Full Text Available The effect of flaxseeds (Linum usitatissimum on rancidity development in frozen whole mackerel (Scomber scombrus was studied. For it, fresh mackerel were dipped in flaxseeds aqueous extract during 60 min, frozen at –80 ºC during 24 hours and kept frozen (–20 ºC up to 12 months. Sampling was carried out on the initial material and at months 1, 3, 5, 7, 9 and 12 of frozen storage at –20 ºC. A parallel experiment with non treated fish was carried out in the same conditions. Rancidity development was measured by several biochemical indices (free fatty acids, peroxides, conjugated dienes and trienes, secondary oxidation products and lipoxygenase activity and complemented by the sensory analysis (skin, flesh odour, consistency and flesh appearance. As a result of the previous antioxidant treatment, peroxides showed to breakdown faster (pSe ha estudiado el efecto del lino (Linum usitatissimum en el desarrollo de rancidez en caballa entera congelada (Scomber scombrus. Para ello, caballas frescas fueron sumergidas en extractos acuosos de semillas de lino durante 60 min, congeladas a -80 ºC durante 24 h y mantenidas congeladas ( -20 ºC durante 12 meses. Se tomaron muestras del material inicial y tras 1, 3, 5, 7, 9 y 12 meses de congelación a -20 ºC . Un experimento paralelo con pescado no tratado fue llevado acabo en las mismas condiciones. El desarrollo de la rancidez fue medido por varios índices bioquímicos (ácidos grasos libres, peróxidos, dienos y trienos conjugados, productos secundarios de oxidación y actividad lipoxigenasa y completado con análisis sensorial (piel, olor de la carne, consistencia y apariencia de la carne. Como resultado del tratamiento antioxidante, los peróxidos se degradaron más rápidos (p < 0.05 después del mes 7, y por tanto, contenidos mayores (p < 0.05 de dienos y trienos conjugados pudieron ser detectados en el pescado tratado. El tratamiento antioxidante también condujo a un

  14. Effect of Previous Irradiation on Vascular Thrombosis of Microsurgical Anastomosis: A Preclinical Study in Rats

    Science.gov (United States)

    Gallardo-Calero, Irene; López-Fernández, Alba; Romagosa, Cleofe; Vergés, Ramona; Aguirre-Canyadell, Marius; Soldado, Francisco; Velez, Roberto

    2016-01-01

    Background: The objective of the present investigation was to compare the effect of neoadjuvant irradiation on the microvascular anastomosis in cervical bundle using an experimental model in rats. Methods: One hundred forty male Sprague–Dawley rats were allocated into 4 groups: group I, control, arterial microanastomosis; group II, control, venous microanastomosis; group III, arterial microanastomosis with previous irradiation (20 Gy); and group IV, venous microanastomosis with previous irradiation (20 Gy). Clinical parameters, technical values of anastomosis, patency, and histopathological parameters were evaluated. Results: Irradiated groups (III and IV) and vein anastomosis groups (II and IV) showed significantly increased technical difficulties. Group IV showed significantly reduced patency rates (7/35) when compared with the control group (0/35). Radiotherapy significantly decreased the patency rates of the vein (7/35) when compared with the artery (1/35). Groups III and IV showed significantly reduced number of endothelial cells and also showed the presence of intimal thickening and adventitial fibrosis as compared with the control group. Conclusion: Neoadjuvant radiotherapy reduces the viability of the venous anastomosis in a preclinical rat model with a significant increase in the incidence of vein thrombosis. PMID:27975009

  15. Thermodynamics of Ligand Binding to Acyl-Coenzyme A Binding Protein Studied by Titration Calorimetry

    DEFF Research Database (Denmark)

    Færgeman, Nils Joakim; Sigurskjold, Bent Walther; Kragelund, Birthe B.

    1996-01-01

    Ligand binding to recombinant bovine acyl-CoA binding protein (ACBP) was examined using isothermal microcalorimetry. Microcalorimetric measurements confirm that the binding affinity of acyl-CoA esters for ACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-...

  16. Thermodynamics of ligand binding to acyl-coenzyme A binding protein studied by titration calorimetry

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; Sigurskjold, B W; Kragelund, B B

    1996-01-01

    Ligand binding to recombinant bovine acyl-CoA binding protein (ACBP) was examined using isothermal microcalorimetry. Microcalorimetric measurements confirm that the binding affinity of acyl-CoA esters for ACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-...

  17. Synthesis, characterization, crystal structure and DNA-binding study ...

    Indian Academy of Sciences (India)

    BOLIN

    SYNOPSIS. Synthesis and characterization of four mononuclear eight coordinated cadmium(II) complexes with newly explored carboxamide derivatives and study of interaction with calf-thymus DNA are reported. The results suggest that neutral complexes 2a and 2b bind to DNA in an intercalative mode. On the other hand, ...

  18. Short term memory for single surface features and bindings in ageing: A replication study.

    Science.gov (United States)

    Isella, Valeria; Molteni, Federica; Mapelli, Cristina; Ferrarese, Carlo

    2015-06-01

    In the present study we replicated a previous experiment investigating visuo-spatial short term memory binding in young and older healthy individuals, in the attempt to verify the pattern of impairment that can be observed in normal elderly for short term memory for single items vs short term memory for bindings. Assessing a larger sample size (25 young and 25 older subjects), using a more appropriate measure of accuracy for a change detection task (A'), and adding the evaluation of speed of performance, we confirmed that old normals show a decline in short term memory for bindings of shape and colour that is of comparable extent, and not major, to the decline in memory for single shapes and single colours. The absence of a specific deficit of short term memory for conjunctions of surface features seems to distinguish cognitive ageing from Alzheimer's Disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Late preterm birth and previous cesarean section: a population-based cohort study.

    Science.gov (United States)

    Yasseen Iii, Abdool S; Bassil, Kate; Sprague, Ann; Urquia, Marcelo; Maguire, Jonathon L

    2018-02-21

    Late preterm birth (LPB) is increasingly common and associated with higher morbidity and mortality than term birth. Yet, little is known about the influence of previous cesarean section (PCS) and the occurrence of LPB in subsequent pregnancies. We aim to evaluate this association along with the potential mediation by cesarean sections in the current pregnancy. We use population-based birth registry data (2005-2012) to establish a cohort of live born singleton infants born between 34 and 41 gestational weeks to multiparous mothers. PCS was the primary exposure, LPB (34-36 weeks) was the primary outcome, and an unplanned or emergency cesarean section in the current pregnancy was the potential mediator. Associations were quantified using propensity weighted multivariable Poisson regression, and mediating associations were explored using the Baron-Kenny approach. The cohort included 481,531 births, 21,893 (4.5%) were LPB, and 119,983 (24.9%) were predated by at least one PCS. Among mothers with at least one PCS, 6307 (5.26%) were LPB. There was increased risk of LPB among women with at least one PCS (adjusted Relative Risk (aRR): 1.20 (95%CI [1.16, 1.23]). Unplanned or emergency cesarean section in the current pregnancy was identified as a strong mediator to this relationship (mediation ratio = 97%). PCS was associated with higher risk of LPB in subsequent pregnancies. This may be due to an increased risk of subsequent unplanned or emergency preterm cesarean sections. Efforts to minimize index cesarean sections may reduce the risk of LPB in subsequent pregnancies.

  20. Structural and binding studies of SAP-1 protein with heparin.

    Science.gov (United States)

    Yadav, Vikash K; Mandal, Rahul S; Puniya, Bhanwar L; Kumar, Rahul; Dey, Sharmistha; Singh, Sarman; Yadav, Savita

    2015-03-01

    SAP-1 is a low molecular weight cysteine protease inhibitor (CPI) which belongs to type-2 cystatins family. SAP-1 protein purified from human seminal plasma (HuSP) has been shown to inhibit cysteine and serine proteases and exhibit interesting biological properties, including high temperature and pH stability. Heparin is a naturally occurring glycosaminoglycan (with varied chain length) which interacts with a number of proteins and regulates multiple steps in different biological processes. As an anticoagulant, heparin enhances inhibition of thrombin by the serpin antithrombin III. Therefore, we have employed surface plasmon resonance (SPR) to improve our understanding of the binding interaction between heparin and SAP-1 (protease inhibitor). SPR data suggest that SAP-1 binds to heparin with a significant affinity (KD = 158 nm). SPR solution competition studies using heparin oligosaccharides showed that the binding of SAP-1 to heparin is dependent on chain length. Large oligosaccharides show strong binding affinity for SAP-1. Further to get insight into the structural aspect of interactions between SAP-1 and heparin, we used modelled structure of the SAP-1 and docked with heparin and heparin-derived polysaccharides. The results suggest that a positively charged residue lysine plays important role in these interactions. Such information should improve our understanding of how heparin, present in the reproductive tract, regulates cystatins activity. © 2014 John Wiley & Sons A/S.

  1. Structural and biochemical studies on ATP binding and hydrolysis by the Escherichia coli RNA chaperone Hfq.

    Directory of Open Access Journals (Sweden)

    Hermann Hämmerle

    Full Text Available In Escherichia coli the RNA chaperone Hfq is involved in riboregulation by assisting base-pairing between small regulatory RNAs (sRNAs and mRNA targets. Several structural and biochemical studies revealed RNA binding sites on either surface of the donut shaped Hfq-hexamer. Whereas sRNAs are believed to contact preferentially the YKH motifs present on the proximal site, poly(A(15 and ADP were shown to bind to tripartite binding motifs (ARE circularly positioned on the distal site. Hfq has been reported to bind and to hydrolyze ATP. Here, we present the crystal structure of a C-terminally truncated variant of E. coli Hfq (Hfq(65 in complex with ATP, showing that it binds to the distal R-sites. In addition, we revisited the reported ATPase activity of full length Hfq purified to homogeneity. At variance with previous reports, no ATPase activity was observed for Hfq. In addition, FRET assays neither indicated an impact of ATP on annealing of two model oligoribonucleotides nor did the presence of ATP induce strand displacement. Moreover, ATP did not lead to destabilization of binary and ternary Hfq-RNA complexes, unless a vast stoichiometric excess of ATP was used. Taken together, these studies strongly suggest that ATP is dispensable for and does not interfere with Hfq-mediated RNA transactions.

  2. Radon diffusion coefficients for soils. Previous studies and their application to uranium-bearing wastes

    International Nuclear Information System (INIS)

    Sasaki, Tomozo; Gunji, Yasuyoshi; Iida, Takao

    2008-01-01

    Radon diffusion in soils has been studied over the years by many researchers. The application of such studies to the evaluation of radiation exposure caused by radon from uranium-bearing wastes disposed in a shallow land site is very important. The present paper surveyed closely relevant studies and elucidated the inherent nature of radon diffusion in terms of the definition of radon diffusion coefficients. Then, basic features of measurement methods for determining radon diffusion coefficients in soils were explained. Furthermore, theoretical aspects of radon diffusion in soils were discussed in terms of microscopic radon diffusion in soils and large-scale radon diffusion through cover soil defects for uranium mill tailings. Finally, in order to apply the radon diffusion studies to uranium-bearing waste disposal in shallow land sites, new challenges were presented: elucidation of radon diffusion in uranium-bearing wastes and cover-soil cracks, and demonstration of the validity of applying only radon diffusion in the evaluation of radiation exposure caused by radon, which would come through Japanese cover soils for uranium-bearing waste disposal. (author)

  3. A time marker instrument for kinematics movement studies: a development of previous versions

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Laburú

    2009-03-01

    Full Text Available This article presents a time marker to study movements in kinematics. It contributes to elaborate a version of time marker which low cost and more efficient in comparison with the marker presented in another work as well as the earlier commercial version.

  4. Segmental hair analysis after a single dose of zolpidem: comparison with a previous study.

    Science.gov (United States)

    Cui, Xiaopei; Xiang, Ping; Zhang, Jingshuo; Shi, Yan; Shen, Baohua; Shen, Min

    2013-01-01

    Hair is a useful aid and sometimes even the only matrix in the analytical strategy in drug-facilitated crime (DFC) investigations. In this novel study, segmental hair analysis was performed after a single 10 mg dose of zolpidem was given to 20 Chinese volunteers. Hair was collected 1 month after administration and was analyzed using ultra-high-pressure liquid chromatography/electrospray ionization tandem mass spectrometry. Zolpidem concentrations were found to be in the range of 135.0-554.6 pg/mg in the proximal 0-2 cm segments. These results were markedly different from those reported by Villain et al., who used volunteers administered equal doses of zolpidem. The analytical method used, as well as the volunteers' hair color, inter-individual variations such as metabolic capacity, hair growth rate, drug incorporation rates, physical state of the hair, age, gender, body weight, etc. and diffusion from sweat or other secretions are all factors that should be considered when interpreting the DFC results.

  5. Life cycle impact assessment of ammonia production in Algeria: A comparison with previous studies

    International Nuclear Information System (INIS)

    Makhlouf, Ali; Serradj, Tayeb; Cheniti, Hamza

    2015-01-01

    In this paper, a Life Cycle Analysis (LCA) from “cradle to gate” of one anhydrous ton of ammonia with a purity of 99% was achieved. Particularly, the energy and environmental performance of the product (ammonia) were evaluated. The eco-profile of the product and the share of each stage of the Life Cycle on the whole environmental impacts have been evaluated. The flows of material and energy for each phase of the life cycle were counted and the associated environmental problems were identified. Evaluation of the impact was achieved using GEMIS 4.7 software. The primary data collection was executed at the production installations located in Algeria (Annaba locality). The analysis was conducted according to the LCA standards ISO 14040 series. The results show that Cumulative Energy Requirement (CER) is of 51.945 × 10 3 MJ/t of ammonia, which is higher than the global average. Global Warming Potential (GWP) is of 1.44 t CO 2 eq/t of ammonia; this value is lower than the world average. Tropospheric ozone precursor and Acidification are also studied in this article, their values are: 549.3 × 10 −6 t NMVOC eq and 259.3 × 10 −6 t SO 2 eq respectively

  6. Structural Studies on Dinuclear Ruthenium(II) Complexes That Bind Diastereoselectively to an Antiparallel Folded Human Telomere Sequence

    Science.gov (United States)

    2013-01-01

    We report DNA binding studies of the dinuclear ruthenium ligand [{Ru(phen)2}2tpphz]4+ in enantiomerically pure forms. As expected from previous studies of related complexes, both isomers bind with similar affinity to B-DNA and have enhanced luminescence. However, when tested against the G-quadruplex from human telomeres (which we show to form an antiparallel basket structure with a diagonal loop across one end), the ΛΛ isomer binds approximately 40 times more tightly than the ΔΔ, with a stronger luminescence. NMR studies show that the complex binds at both ends of the quadruplex. Modeling studies, based on experimentally derived restraints obtained for the closely related [{Ru(bipy)2}2tpphz]4+, show that the ΛΛ isomer fits neatly under the diagonal loop, whereas the ΔΔ isomer is unable to bind here and binds at the lateral loop end. Molecular dynamics simulations show that the ΔΔ isomer is prevented from binding under the diagonal loop by the rigidity of the loop. We thus present a novel enantioselective binding substrate for antiparallel basket G-quadruplexes, with features that make it a useful tool for quadruplex studies. PMID:24088028

  7. Calorimetric study of binding of some disaccharides with crown ethers

    International Nuclear Information System (INIS)

    Davydova, Olga I.; Lebedeva, Nataliya Sh.; Parfenyuk, Elena V.

    2004-01-01

    Isothermal titration calorimetry has been applied to the determination of the thermodynamic parameters of binding of β-lactose, α,α-trehalose and sucrose with 15-crown-5 and 18-crown-6 in water at 298.15 K. The formation of 1:1 molecular associates has been found for the systems studied except 18-crown-6 and β-lactose. The associates are preferentially or completely entropy stabilized. The most stable associate is formed between α,α-trehalose and 18-crown-6. The obtained values of thermodynamic parameters of binding are discussed from the point of view of solute-solvent interactions as well as conformational and structural peculiarities of the disaccharides (DS) and crown ethers (CE)

  8. Equilibrium binding studies of mono, di and triisocyanide ligands on Au powder surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ontko, Alyn [Iowa State Univ., Ames, IA (United States)

    1997-10-08

    The author`s group has previously shown that isocyanides are readily adsorbed from solutions to Au powder and bind to the Au surface in an end-on fashion through the terminal carbon. Later work demonstrated that the equilibrium constants for the reversible adsorption of electronically inequivalent isocyanides could be obtained using the Langmuir isotherm technique. This dissertation describes two projects completed which complement the initial findings of this group. Initially, several alkylisocyanides were synthesized to examine the effect of tail length on Au powder adsorption. It was observed that the length of the alkyl chain affected not only the Au surface binding affinity, but also the rate of surface saturation and saturation coverage values. Direct competition studies were also studied using a 13C-labeled isocyanide. These studies demonstrated the stabilization afforded by substrate-substrate packing forces in SAM`s formed by the longer chain isocyanides. In a second study, di and triisocyanides were synthesized to determine the effect that the length of the connecting link and the number of isocyanide groups (as points of attachment) have on Au adsorption stability. The work in this area describes the binding modes, relative binding affinities and surface coverage values for a series of flexible alkyl and xylyldiisocyanides on Au powder surfaces. This report contains only the introductory material, and general summary. Two chapters have been processed separately. 56 refs.

  9. Photoaffinity studies of the tubulin-colchicine binding site

    International Nuclear Information System (INIS)

    Hahn, K.M.

    1987-01-01

    A variety of colchicine derivatives were synthesized and coupled with 3,3,3-trifluoro-2-diazapropionyl chloride (TFDP-Cl) to produce colchicine photoaffinity analogs for use in tubulin labelling studies. Photoaffinity analogs of allocolchicine and podophylotoxin were also made using the same photoreactive moiety. Several labels were found to be effective inhibitors of tubulin polymerization. The approximate tubulin binding constants of the labels, calculated from polymerization inhibition data, varied between 2.2 x 10 5 to 2.5 x 10 3 M -1 . The labels chosen for use in tubulin labelling experiments were (N-TFDP) deacetyl-thiocolchicine 1, (O-TFDP)thiocolchifoline 2, and (O-TFDP)-2-demethylthiocolchicine 3. Compound 1 was found to bind tubulin reversibly and to competitively inhibit colchicine binding. Methods for the incorporation of tritium and 14 C in these labels were developed. Conditions were found which caused labels to insert into solvent without photorearrangement of the colchicine skeleton. Catalytic base caused the α-diazo amide of 1 to rearrange to a triazole

  10. Effect of Acupressure, Acupuncture and Moxibustion in Women With Pregnancy-Related Anxiety and Previous Depression: A Preliminary Study

    OpenAIRE

    Suzuki, Shunji; Tobe, Chiharu

    2017-01-01

    Background In this preliminary study, we examined the effect of acupressure, acupuncture and moxibustion (oriental treatments) to prevent of the relapse/deterioration of perinatal depression in women with pregnancy-related anxiety and previous depression. Methods and results Between 2014 and 2016, there were 48 women with pregnancy-related anxiety and previous depression who had delivery at ? 22 weeks? gestation in our institute. Of these, oriental treatments were performed in eight and two w...

  11. DNA-binding cytotoxic alkaloids: comparative study of the energetics of binding of berberine, palmatine, and coralyne.

    Science.gov (United States)

    Bhadra, Kakali; Maiti, Motilal; Kumar, Gopinatha Suresh

    2008-12-01

    Deoxyribonucleic acid is the site of storage and retrieval of genetic information through interaction with proteins and other small molecules. In the present study, the interaction of two natural cytotoxic protoberberine plant alkaloids, berberine and palmatine, and a synthetic derivative, coralyne, with mammalian herring testis DNA was investigated using a combination of isothermal titration calorimetry, differential scanning calorimetry, and optical melting experiments to characterize the energetics of their binding. The binding constants of these alkaloids to DNA under identical conditions were evaluated from the UV melting data, and the enthalpy of binding was elucidated from isothermal titration studies. The binding constants of berberine, palmatine, and coralyne to DNA were found to be 1.15 x 10(4), 2.84 x 10(4), and 3.5 x 10(6) M(-1) at 20 degrees C in buffer of 20 mM [Na+]. Parsing of the free energy change of the interaction observed into polyelectrolytic and nonpolyelectrolytic components suggested that although these alkaloids are charged, the major contributor of about 75% of the binding free energy arises from the nonpolyelectrolytic forces. The binding in case of palmatine and coralyne was predominantly enthalpy driven with favoring smaller entropy terms, while that of berberine was favored by both negative enthalpy and positive entropy changes. Temperature dependence of the binding enthalpies determined from ITC studies in the range 20-40 degrees C was used to calculate the binding-induced change in heat capacity (DeltaC(o)(p)) values as -117, -135, and -157 cal/mol K, respectively, for berberine, palmatine, and coralyne. Taken together, the results suggest that the DNA binding of the planar synthetic coralyne is stronger and thermodynamically more favored compared to the buckled natural berberine and palmatine.

  12. Comparison Study on Polysaccharide Fractions from Laminaria japonica: Structural Characterization and Bile Acid Binding Capacity.

    Science.gov (United States)

    Gao, Jie; Lin, Lianzhu; Sun, Baoguo; Zhao, Mouming

    2017-11-08

    Our previous study has suggested that the crude polysaccharide obtained from Laminaria japonica by acid assisted extraction (LP-A) have significant bile acid-binding capacity, which probably ascribed to its specific structure characterization. The relationship between structure characterization and bile acid-binding capacity of the purified LP-A fractions are still unknown. This paper conducted a comparison study on the structure characterization and bile acid-binding capacity of three LP-A fractions (LP-A4, LP-A6, and LP-A8). The results indicated that LP-A4, LP-A6, and LP-A8, characterized as mannoglucan, fucomannoglucan, and fucogalactan, had significantly different structure characterization. Furthermore, the bile acid-binding capacity of LP-A8 was obviously higher than the other fractions, which may be attributed to its highly branched structure, abundant sulfate, fucose, and galactose in chemical composition and denser interconnected macromolecule network in molecular morphology. This study provides scientific evidence for the potential utilization of LP-A8 as an attractive functional food supplement candidate for the hyperlipidemia population.

  13. Molecular determinants of epidermal growth factor binding: a molecular dynamics study.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Sanders

    Full Text Available The epidermal growth factor receptor (EGFR is a member of the receptor tyrosine kinase family that plays a role in multiple cellular processes. Activation of EGFR requires binding of a ligand on the extracellular domain to promote conformational changes leading to dimerization and transphosphorylation of intracellular kinase domains. Seven ligands are known to bind EGFR with affinities ranging from sub-nanomolar to near micromolar dissociation constants. In the case of EGFR, distinct conformational states assumed upon binding a ligand is thought to be a determining factor in activation of a downstream signaling network. Previous biochemical studies suggest the existence of both low affinity and high affinity EGFR ligands. While these studies have identified functional effects of ligand binding, high-resolution structural data are lacking. To gain a better understanding of the molecular basis of EGFR binding affinities, we docked each EGFR ligand to the putative active state extracellular domain dimer and 25.0 ns molecular dynamics simulations were performed. MM-PBSA/GBSA are efficient computational approaches to approximate free energies of protein-protein interactions and decompose the free energy at the amino acid level. We applied these methods to the last 6.0 ns of each ligand-receptor simulation. MM-PBSA calculations were able to successfully rank all seven of the EGFR ligands based on the two affinity classes: EGF>HB-EGF>TGF-α>BTC>EPR>EPG>AR. Results from energy decomposition identified several interactions that are common among binding ligands. These findings reveal that while several residues are conserved among the EGFR ligand family, no single set of residues determines the affinity class. Instead we found heterogeneous sets of interactions that were driven primarily by electrostatic and Van der Waals forces. These results not only illustrate the complexity of EGFR dynamics but also pave the way for structure-based design of

  14. Estimating the effect of current, previous and never use of drugs in studies based on prescription registries

    DEFF Research Database (Denmark)

    Nielsen, Lars Hougaard; Løkkegaard, Ellen; Andreasen, Anne Helms

    2009-01-01

    PURPOSE: Many studies which investigate the effect of drugs categorize the exposure variable into never, current, and previous use of the study drug. When prescription registries are used to make this categorization, the exposure variable possibly gets misclassified since the registries do not ca...

  15. Maternal and perinatal outcomes of delivery after a previous Cesarean section in Enugu, Southeast Nigeria: a prospective observational study.

    Science.gov (United States)

    Ugwu, George O; Iyoke, Chukwuemeka A; Onah, Hyacinth E; Egwuatu, Vincent E; Ezugwu, Frank O

    2014-01-01

    Obstetricians in developing countries appear generally reluctant to conduct vaginal delivery in women with a previous Cesarean because of lack of adequate facilities for optimal fetomaternal monitoring. To describe delivery outcomes among women with one previous Cesarean section at a tertiary hospital in Southeast Nigeria. This was a prospective observational study to determine maternal and perinatal outcomes of attempted vaginal birth after Cesarean sections (VBAC) following one previous Cesarean section. Analysis was done with SPSS statistical software version 17.0 for Windows using descriptive and inferential statistics at 95% level of confidence. Two thousand six hundred and ten women delivered in the center during the study period, of whom 395 had one previous Cesarean section. A total of 370 women with one previous Cesarean section had nonrecurrent indications, of whom 355 consenting pregnant women with one previous Cesarean section were studied. A majority of the women (320/355, 90.1%) preferred to have vaginal delivery despite the one previous Cesarean section. However, only approximately 54% (190/355) were found suitable for trial of VBAC, out of whom 50% (95/190 had successful VBAC. Ninety-five women (50.0%) had failed attempt at VBAC and were delivered by emergency Cesarean section while 35 women (9.8%) had emergency Cesarean section for other obstetric indications (apart from failed VBAC). There was no case of uterine rupture or neonatal and maternal deaths recorded in any group. Apgar scores of less than 7 in the first minute were significantly more frequent amongst women who had vaginal delivery when compared to those who had elective repeat Cesarean section (P=0.03). Most women who had one previous Cesarean delivery chose to undergo trial of VBAC, although only about half were considered suitable for VBAC. The maternal and fetal outcomes of trial of VBAC in selected women with one previous Cesarean delivery for non-recurrent indications were good

  16. Binding Studies of Lamotrigine with Sera of Different Animal Species

    African Journals Online (AJOL)

    Erah

    into the mechanism of interaction, evaluate the effect of dielectric constant on binding affinity, and to determine the effect of ..... Physico-chemical aspects of protein binding of nimesulide, Ind J. Pharm Sci, 2005; 2: 243-246. 10. Dutta, SK, Basu, SK, Sen KK. Binding of diclofenac sodium with bovine serum albumin at different ...

  17. NMR studies on DNA binding specificity of the lac repressor

    NARCIS (Netherlands)

    Kopke Salinas, Roberto

    2005-01-01

    The thesis describes NMR structures of two protein-DNA complexes. The first structure shows how the protein, the DNA binding domain of lac repressor, recognizes its natural DNA binding site, by adaptation and read out of the nucleotide sequence. The second one shows how the DNA binding specificity

  18. Identification of novel allosteric modulator binding sites in NMDA receptors: A molecular modeling study.

    Science.gov (United States)

    Kane, Lucas T; Costa, Blaise M

    2015-09-01

    The dysfunction of N-methyl-d-Aspartate receptors (NMDARs), a subtype of glutamate receptors, is correlated with schizophrenia, stroke, and many other neuropathological disorders. However, not all NMDAR subtypes equally contribute towards these disorders. Since NMDARs composed of different GluN2 subunits (GluN2A-D) confer varied physiological properties and have different distributions in the brain, pharmacological agents that target NMDARs with specific GluN2 subunits have significant potential for therapeutic applications. In our previous research, we have identified a family of novel allosteric modulators that differentially potentiate and/or inhibit NMDARs of differing GluN2 subunit composition. To further elucidate their molecular mechanisms, in the present study, we have identified four potential binding sites for novel allosteric modulators by performing molecular modeling, docking, and in silico mutations. The molecular determinants of the modulator binding sites (MBS), analysis of particular MBS electrostatics, and the specific loss or gain of binding after mutations have revealed modulators that have strong potential affinities for specific MBS on given subunits and the role of key amino acids in either promoting or obstructing modulator binding. These findings will help design higher affinity GluN2 subunit-selective pharmaceuticals, which are currently unavailable to treat psychiatric and neurological disorders. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Structural study and thermodynamic characterization of inhibitor binding to lumazine synthase from Bacillus anthracis

    Energy Technology Data Exchange (ETDEWEB)

    Morgunova, Ekaterina [Karolinska Institutet NOVUM, Center of Structural Biochemistry, Hälsovägen 7-9, 141 57 Huddinge (Sweden); Illarionov, Boris; Saller, Sabine [Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany); Popov, Aleksander [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble CEDEX 09 (France); Sambaiah, Thota [Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University (United States); Bacher, Adelbert [Chemistry Department, Technical University of Munich, 85747 Garching (Germany); Cushman, Mark [Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University (United States); Fischer, Markus [Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany); Ladenstein, Rudolf, E-mail: rudolf.ladenstein@ki.se [Karolinska Institutet NOVUM, Center of Structural Biochemistry, Hälsovägen 7-9, 141 57 Huddinge (Sweden)

    2010-09-01

    Crystallographic studies of lumazine synthase, the penultimate enzyme of the riboflavin-biosynthetic pathway in B. anthracis, provide a structural framework for the design of antibiotic inhibitors, together with calorimetric and kinetic investigations of inhibitor binding. The crystal structure of lumazine synthase from Bacillus anthracis was solved by molecular replacement and refined to R{sub cryst} = 23.7% (R{sub free} = 28.4%) at a resolution of 3.5 Å. The structure reveals the icosahedral symmetry of the enzyme and specific features of the active site that are unique in comparison with previously determined orthologues. The application of isothermal titration calorimetry in combination with enzyme kinetics showed that three designed pyrimidine derivatives bind to lumazine synthase with micromolar dissociation constants and competitively inhibit the catalytic reaction. Structure-based modelling suggested the binding modes of the inhibitors in the active site and allowed an estimation of the possible contacts formed upon binding. The results provide a structural framework for the design of antibiotics active against B. anthracis.

  20. Treatment of osteochondral defects of the talus with a metal resurfacing inlay implant after failed previous surgery: a prospective study

    NARCIS (Netherlands)

    van Bergen, C. J. A.; van Eekeren, I. C. M.; Reilingh, M. L.; Sierevelt, I. N.; van Dijk, C. N.

    2013-01-01

    We have evaluated the clinical effectiveness of a metal resurfacing inlay implant for osteochondral defects of the medial talar dome after failed previous surgical treatment. We prospectively studied 20 consecutive patients with a mean age of 38 years (20 to 60), for a mean of three years (2 to 5)

  1. Small world network strategies for studying protein structures and binding.

    Science.gov (United States)

    Taylor, Neil R

    2013-01-01

    Small world network concepts provide many new opportunities to investigate the complex three dimensional structures of protein molecules. This mini-review explores the published literature on using small-world network approaches to study protein structure, with emphasis on the different combinations of descriptors that have been tested, on studies involving ligand binding in protein-ligand complexes, and on protein-protein complexes. The benefits and success of small world network approaches, which change the focus from specific interactions to the local environment, even to non-local phenomenon, are described. The purpose is to show the different ways that small world network concepts have been used for building new computational models for studying protein structure and function, and for extending and improving existing modelling approaches.

  2. An fMRI study of neuronal activation in schizophrenia patients with and without previous cannabis use

    Directory of Open Access Journals (Sweden)

    Else-Marie eLøberg

    2012-10-01

    Full Text Available Previous studies have mostly shown positive effects of cannabis use on cognition in patients with schizophrenia, which could reflect lower neurocognitive vulnerability. There are however no studies comparing whether such cognitive differences have neuronal correlates. Thus, the aim of the present study was to compare whether patients with previous cannabis use differ in brain activation from patients who has never used cannabis. The patients groups were compared on the ability to up-regulate an effort mode network during a cognitive task and down-regulate activation in the same network during a task-absent condition. Task-present and task-absent brain activation was measured by functional magnetic resonance neuroimaging (fMRI. Twenty-six patients with a DSM-IV and ICD-10 diagnosis of schizophrenia were grouped into a previous cannabis user group and a no-cannabis group. An auditory dichotic listening task with instructions of attention focus on either the right or left ear stimulus was used to tap verbal processing, attention and cognitive control, calculated as an aggregate score. When comparing the two groups, there were remaining activations in the task-present condition for the cannabis group, not seen in the no-cannabis group, while there was remaining activation in the task-absent condition for the no-cannabis group, not seen in the cannabis group. Thus, the patients with previous cannabis use showed increased activation in an effort mode network and decreased activation in the default mode network as compared to the no-cannabis group. It is concluded that the present study show some differences in brain activation to a cognitively challenging task between previous cannabis and no-cannabis schizophrenia patients.

  3. Human islet amyloid polypeptide fibril binding to catalase: a transmission electron microscopy and microplate study.

    Science.gov (United States)

    Milton, Nathaniel G N; Harris, J Robin

    2010-05-18

    The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-beta (A-beta) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to A-beta fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)-based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77 nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu-like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, A-beta, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  4. Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

    Directory of Open Access Journals (Sweden)

    Nathaniel G. N. Milton

    2010-01-01

    Full Text Available The diabetes-associated human islet amyloid polypeptide (IAPP is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ and prion protein (PrP fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  5. X-ray diffraction study of the binding of the antisickling agent 12C79 to human hemoglobin

    International Nuclear Information System (INIS)

    Wireko, R.C.; Abraham, D.J.

    1991-01-01

    The hemoglobin binding site of the antisickling agent 12C79 has been determined by x-ray crystallography. 12C79 is recognized as one of the first molecules to reach clinical trials that was designed, de novo, from x-ray-determined atomic coordinates of a protein. Several previous attempts to verify the proposed Hb binding sites via crystallographic studies have failed. Using revised experimental procedures, the authors obtained 12C79-deoxhemoglobin crystals grown after reaction with oxyhemoglobin and cyanoborohydride reduction to stabilize the Schiff base linkage. The difference electron-density Fourier maps show that two 12C79 molecules bind covalently to both symmetry-related N-terminal amino groups of the hemoglobin α chains. This is in contrast to the original design that proposed the binding of one drug molecule that spans the molecular dyad to interact with both N-terminal α-amino groups

  6. Cytotoxic, DNA binding, DNA cleavage and antibacterial studies of ...

    Indian Academy of Sciences (India)

    ofloxacin and sparfloxacin with diverse metal ions.9–17. In continuation of our previous work,18 this paper ... minimum inhibitory concentration (MIC) study has been performed by means of laminar air flow cabinet ..... the volume has been adjusted with artificial seawater to. 2.5 mL per vial. After 24 h. the number of survivors.

  7. Studies on the chitin/chitosan binding properties of six cuticular proteins analogous to peritrophin 3 from Bombyx mori.

    Science.gov (United States)

    Qu, M; Ren, Y; Liu, Y; Yang, Q

    2017-08-01

    Chitin deacetylation is required to make the cuticle rigid and compact through chitin chain crosslinking. Thus it is presumed that specialized proteins are required to bind deacetylated chitin chains together. However, deacetylated-chitin binding proteins have not ever been reported. In a previous work, six cuticular proteins analogous to peritrophin 3 (CPAP3s) were found to be abundant in the moulting fluid of Bombyx mori. In this study, these BmCPAP3s (BmCPAP3-A1, BmCPAP3-A2, BmCPAP3-B, BmCPAP3-C, BmCPAP3-D1 and BmCPAP3-D2) were cloned and expressed in Escherichia coli and purified using metal-chelating affinity chromatography. Their binding activities demonstrated that although all of the BmCPAP3s showed similar binding abilities toward crystalline chitin and colloidal chitin, they differed in their affinities toward partially and fully deacetylated chitin. Amongst them, BmCPAP3-D1 exhibited the highest binding activity toward deacetylated chitin. The gene expression pattern of BmCPAP3-D1 was similar to BmCPAP3-A1 and BmCPAP3-C at most stages except that it was dramatically upregulated at the beginning of the pupa to adult transition stage. This work is the first report of a chitin-binding protein, BmCPAP3-D1, which exhibits high binding affinity to deacetylated chitin. © 2017 The Royal Entomological Society.

  8. Synthesis, characterization, crystal structure and DNA-binding study ...

    Indian Academy of Sciences (India)

    BOLIN

    The results suggest that neutral complexes 2a and 2b bind to DNA in an intercalative mode. On the other hand, cationic complexes 1a and 1b interact with DNA via weak intercalative or groove binding mode. (NOTE: See more examples of Graphical Abstracts in Journal website, http://www.ias.ac.in/chemsci/index.html under ...

  9. Studies of the silencing of Baculovirus DNA binding protein

    NARCIS (Netherlands)

    Quadt, I.; Lent, van J.W.M.; Knebel-Morsdorf, D.

    2007-01-01

    Baculovirus DNA binding protein (DBP) binds preferentially single-stranded DNA in vitro and colocalizes with viral DNA replication sites. Here, its putative role as viral replication factor has been addressed by RNA interference. Silencing of DBP in Autographa californica multiple

  10. Genome-scale study of the importance of binding site context for transcription factor binding and gene regulation

    Directory of Open Access Journals (Sweden)

    Ronne Hans

    2008-11-01

    Full Text Available Abstract Background The rate of mRNA transcription is controlled by transcription factors that bind to specific DNA motifs in promoter regions upstream of protein coding genes. Recent results indicate that not only the presence of a motif but also motif context (for example the orientation of a motif or its location relative to the coding sequence is important for gene regulation. Results In this study we present ContextFinder, a tool that is specifically aimed at identifying cases where motif context is likely to affect gene regulation. We used ContextFinder to examine the role of motif context in S. cerevisiae both for DNA binding by transcription factors and for effects on gene expression. For DNA binding we found significant patterns of motif location bias, whereas motif orientations did not seem to matter. Motif context appears to affect gene expression even more than it affects DNA binding, as biases in both motif location and orientation were more frequent in promoters of co-expressed genes. We validated our results against data on nucleosome positioning, and found a negative correlation between preferred motif locations and nucleosome occupancy. Conclusion We conclude that the requirement for stable binding of transcription factors to DNA and their subsequent function in gene regulation can impose constraints on motif context.

  11. Changes in association between previous therapeutic abortion and preterm birth in Scotland, 1980 to 2008: a historical cohort study.

    Directory of Open Access Journals (Sweden)

    Clare Oliver-Williams

    Full Text Available Numerous studies have demonstrated that therapeutic termination of pregnancy (abortion is associated with an increased risk of subsequent preterm birth. However, the literature is inconsistent, and methods of abortion have changed dramatically over the last 30 years. We hypothesized that the association between previous abortion and the risk of preterm first birth changed in Scotland between 1 January 1980 and 31 December 2008.We studied linked Scottish national databases of births and perinatal deaths. We analysed the risk of preterm birth in relation to the number of previous abortions in 732,719 first births (≥24 wk, adjusting for maternal characteristics. The risk (adjusted odds ratio [95% CI] of preterm birth was modelled using logistic regression, and associations were expressed for a one-unit increase in the number of previous abortions. Previous abortion was associated with an increased risk of preterm birth (1.12 [1.09-1.16]. When analysed by year of delivery, the association was strongest in 1980-1983 (1.32 [1.21-1.43], progressively declined between 1984 and 1999, and was no longer apparent in 2000-2003 (0.98 [0.91-1.05] or 2004-2008 (1.02 [0.95-1.09]. A statistical test for interaction between previous abortion and year was highly statistically significant (p<0.001. Analysis of data for abortions among nulliparous women in Scotland 1992-2008 demonstrated that the proportion that were surgical without use of cervical pre-treatment decreased from 31% to 0.4%, and that the proportion of medical abortions increased from 18% to 68%.Previous abortion was a risk factor for spontaneous preterm birth in Scotland in the 1980s and 1990s, but the association progressively weakened and disappeared altogether by 2000. These changes were paralleled by increasing use of medical abortion and cervical pre-treatment prior to surgical abortion. Although it is plausible that the two trends were related, we could not test this directly as the data on

  12. Previous early antenatal service utilization improves timely booking: cross-sectional study at university of Gondar hospital, northwest Ethiopia.

    Science.gov (United States)

    Belayneh, Tadesse; Adefris, Mulat; Andargie, Gashaw

    2014-01-01

    Early booking of antenatal care (ANC) is regarded as a cornerstone of maternal and neonatal health care. However, existing evidence from developing countries indicate that lots of pregnant woman begin ANC booking lately. Objective. It was aimed to assess timing of ANC booking and associated factors among pregnant women attending ANC clinic at University of Gondar Hospital, 2013. An institution based cross-sectional study design was used to collect data with a face-to-face interview technique. Bivariate and multivariate analysis was used to identify associated factors for early ANC visit using SPSS version 20. From total women (N = 369) interviewed, 47.4% were timely booked. Mothers with younger age (AOR = 3.83, 95% CI: 1.89, 10.53), formal education (AOR = 1.06, 95% CI: 1.03, -7.61), previous early ANC visit (AOR = 2.39, 95% CI: 2.23, 9.86), and perceived ANC visit per pregnancy of four and greater were significantly associated with early ANC visit. Although late booking is a problem in this study, previous early utilization of ANC visit favors current timely booking. This indicates that the importance of early booking was appropriately addressed from previous visits. Counseling of timely booking during ANC visit should be strengthened. Moreover, empowering through education is also recommended.

  13. Effect of Acupressure, Acupuncture and Moxibustion in Women With Pregnancy-Related Anxiety and Previous Depression: A Preliminary Study.

    Science.gov (United States)

    Suzuki, Shunji; Tobe, Chiharu

    2017-06-01

    In this preliminary study, we examined the effect of acupressure, acupuncture and moxibustion (oriental treatments) to prevent of the relapse/deterioration of perinatal depression in women with pregnancy-related anxiety and previous depression. Between 2014 and 2016, there were 48 women with pregnancy-related anxiety and previous depression who had delivery at ≥ 22 weeks' gestation in our institute. Of these, oriental treatments were performed in eight and two women (totally 10, 21%) during pregnancy and postpartum, respectively. One of the 10 (10%) who received oriental treatments admitted depressive symptoms during pregnancy or postpartum, while 18 of the rest 38 who did not receive oriental treatments admitted depressive symptoms (47%, P = 0.065). The oriental treatments may be useful for pregnant women who need perinatal mental health care.

  14. [Cervical ripening after previous cesarean section with Foley catheter: A prospective study of 41 patients].

    Science.gov (United States)

    Lamourdedieu, C; Gnisci, A; Marcelli, M; Heckenroth, H; Gamerre, M; Agostini, A

    2015-05-01

    Effectiveness of cervical ripening with Foley catheter for patients requiring labor induction with a previous cesarean section and unfavorable cervical conditions. Prospective unicentric study conducted between 1 April 2011 and 31 October 2013 on 41 patients with medical indication for labor induction with a Bishop's scorecesarean section. Outcomes evaluated were mode of delivery, Bishop's score variations and maternal or neonatal complications. Cervical ripening was performed in 39 patients and 17 (43.5%) were delivered vaginally. A total of 24/39 (61.5%) patients were put into work and 10/39 (25.6%) came into work immediately after removal of the Foley catheter. The average score improvement Bishop was 2.7±0.6 points. No maternal or fetal complication was reported. Foley catheter is an interesting procedure in patients with previous cesarean section and unfavorable cervical conditions requiring labor induction. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  15. Binding of ethyl pyruvate to bovine serum albumin: Calorimetric, spectroscopic and molecular docking studies

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, Mallika [Department of Chemistry, Miranda House, University of Delhi, Delhi 11007 (India); Mishra, Rashmi; Agarwala, Paban K. [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Ojha, Himanshu, E-mail: himanshu.drdo@gmail.com [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Singh, Bhawna [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Singh, Anju; Kukreti, Shrikant [Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi 11007 (India)

    2016-06-10

    Highlights: • ITC study showed binding of ethyl pyruvate with BSA with high binding affinity. • Ethyl pyruvate binding caused conformation alteration of BSA. • Fluorescence quenching mechanism is static in nature. • Electrostatic, hydrogen bonding and hydrophobic forces involved in binding. • Docking confirmed role of electrostatic, hydrogen bonding and hydrophobic forces. - Abstract: Various in vitro and in vivo studies have shown the anti-inflammatory and anticancer potential role of ethyl pyruvate. Bio-distribution of drugs is significantly influenced by the drug-serum protein binding. Therefore, the binding mechanism of the ethyl pyruvate with bovine serum albumin was investigated using UV–vis absorption, fluorescence, circular dichroism, isothermal titration calorimetry and molecular docking techniques. Absorption and fluorescence quenching studies indicated the binding of ethyl pyruvate with protein. Circular dichroism spectra of bovine serum albumin confirmed significant change in the conformation of protein upon binding. Thermodynamic data confirmed that ethyl pyruvate binds to bovine serum albumin at the two different sites with high affinity. Binding of ethyl pyruvate to bovine serum albumin involves hydrogen bonding, van der Waal and hydrophobic interactions. Further, docking studies indicated that ethyl pyruvate could bind significantly at the three binding sites. The results will definitely contribute to the development of ethyl pyruvate as drug.

  16. EPR studies of intermolecular interactions and competitive binding of drugs in a drug-BSA binding model.

    Science.gov (United States)

    Akdogan, Y; Emrullahoglu, M; Tatlidil, D; Ucuncu, M; Cakan-Akdogan, G

    2016-08-10

    Understanding intermolecular interactions between drugs and proteins is very important in drug delivery studies. Here, we studied different binding interactions between salicylic acid and bovine serum albumin (BSA) using electron paramagnetic resonance (EPR) spectroscopy. Salicylic acid was labeled with a stable radical (spin label) in order to monitor its mobilized (free) or immobilized (bound to BSA) states. In addition to spin labeled salicylic acid (SL-salicylic acid), its derivatives including SL-benzoic acid, SL-phenol, SL-benzene, SL-cyclohexane and SL-hexane were synthesized to reveal the effects of various drug binding interactions. EPR results of these SL-molecules showed that hydrophobic interaction is the main driving force. Whereas each of the two functional groups (-COOH and -OH) on the benzene ring has a minute but detectable effect on the drug-protein complex formation. In order to investigate the effect of electrostatic interaction on drug binding, cationic BSA (cBSA) was synthesized, altering the negative net charge of BSA to positive. The salicylic acid loading capacity of cBSA is significantly higher compared to that of BSA, indicating the importance of electrostatic interaction in drug binding. Moreover, the competitive binding properties of salicylic acid, ibuprofen and aspirin to BSA were studied. The combined EPR results of SL-salicylic acid/ibuprofen and SL-ibuprofen/salicylic acid showed that ibuprofen is able to replace up to ∼83% of bound SL-salicylic acid, and salicylic acid can replace only ∼14% of the bound SL-ibuprofen. This indicates that ∼97% of all salicylic acid and ibuprofen binding sites are shared. On the other hand, aspirin replaces only ∼23% of bound SL-salicylic acid, and salicylic acid replaces ∼50% of bound SL-aspirin, indicating that ∼73% of all salicylic acid and aspirin binding sites are shared. These results show that EPR spectroscopy in combination with the spin labeling technique is a very powerful

  17. Binding of (/sup 3/H)imipramine to human platelet membranes with compensation for saturable binding to filters and its implication for binding studies with brain membranes

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, O.M.; Wood, K.M.; Williams, D.C.

    1984-08-01

    Apparent specific binding of (/sup 3/H)imipramine to human platelet membranes at high concentrations of imipramine showed deviation from that expected of a single binding site, a result consistent with a low-affinity binding site. The deviation was due to displaceable, saturable binding to the glass fibre filters used in the assays. Imipramine, chloripramine, desipramine, and fluoxetine inhibited binding to filters whereas 5-hydroxytryptamine and ethanol were ineffective. Experimental conditions were developed that eliminated filter binding, allowing assay of high- and low-affinity binding to membranes. Failure to correct for filter binding may lead to overestimation of binding parameters, Bmax and KD for high-affinity binding to membranes, and may also be misinterpreted as indicating a low-affinity binding component in both platelet and brain membranes. Low-affinity binding (KD less than 2 microM) of imipramine to human platelet membranes was demonstrated and its significance discussed.

  18. Antimicrobial activity, cytotoxicity and DNA binding studies of carbon dots

    Science.gov (United States)

    Jhonsi, Mariadoss Asha; Ananth, Devanesan Arul; Nambirajan, Gayathri; Sivasudha, Thilagar; Yamini, Rekha; Bera, Soumen; Kathiravan, Arunkumar

    2018-05-01

    In recent years, quantum dots (QDs) are one of the most promising nanomaterials in life sciences community due to their unexploited potential in biomedical applications; particularly in bio-labeling and sensing. In the advanced nanomaterials, carbon dots (CDs) have shown promise in next generation bioimaging and drug delivery studies. Therefore the knowledge of the exact nature of interaction with biomolecules is of great interest to designing better biosensors. In this study, the interaction between CDs derived from tamarind and calf thymus DNA (ct-DNA) has been studied by vital spectroscopic techniques, which revealed that the CDs could interact with DNA via intercalation. The apparent association constant has been deduced from the absorption spectral changes of ct-DNA-CDs using the Benesi-Hildebrand equation. From the DNA induced emission quenching experiments the apparent DNA binding constant of the CDs (Kapp) have also been evaluated. Furthermore, we have analyzed the antibacterial and antifungal activity of CDs using disc diffusion assay method which exhibited excellent activity against E. coli and C. albicans with inhibition zone in the range of 7-12 mm. The biocompatible nature of CDs was confirmed by an in vitro cytotoxicity test on L6 normal rat myoblast cells by using MTT assay. The cell viability is not affected till the high dosage of CDs (200 μg/mL) for >48 h. As a consequence of the work, future development of CDs for microbial control and DNA sensing among the various biomolecules is possible in view of emerging biofields.

  19. Previous experiences and emotional baggage as barriers to lifestyle change - a qualitative study of Norwegian Healthy Life Centre participants.

    Science.gov (United States)

    Følling, Ingrid S; Solbjør, Marit; Helvik, Anne-S

    2015-06-23

    Changing lifestyle is challenging and difficult. The Norwegian Directorate of Health recommends that all municipalities establish Healthy Life Centres targeted to people with lifestyle issues. Little is known about the background, experiences and reflections of participants. More information is needed about participants to shape effective lifestyle interventions with lasting effect. This study explores how participants in a lifestyle intervention programme describe previous life experiences in relation to changing lifestyle. Semi-structured qualitative in-depth interviews were performed with 23 participants (16 women and 7 men) aged 18 - 70 years. The data were analysed using systematic text condensation searching for issues describing participants' responses, and looking for the essence, aiming to share the basis of life-world experiences as valid knowledge. Participants identified two main themes: being stuck in old habits, and being burdened with emotional baggage from their previous negative experiences. Participants expressed a wish to change their lifestyles, but were unable to act in accordance with the health knowledge they possessed. Previous experiences with lifestyle change kept them from initiating attempts without professional assistance. Participants also described being burdened by an emotional baggage with problems from childhood and/or with family, work and social life issues. Respondents said that they felt that emotional baggage was an important explanation for why they were stuck in old habits and that conversely, being stuck in old habits added load to their already emotional baggage and made it heavier. Behavioural change can be hard to perform as psychological distress from life baggage can influence the ability to change. The study participants' experience of being stuck in old habits and having substantial emotional baggage raises questions as to whether or not Healthy Life Centres are able to help participants who need to make a lifestyle

  20. Outcomes of induction of labour in women with previous caesarean delivery: a retrospective cohort study using a population database.

    Directory of Open Access Journals (Sweden)

    Sarah J Stock

    Full Text Available There is evidence that induction of labour (IOL around term reduces perinatal mortality and caesarean delivery rates when compared to expectant management of pregnancy (allowing the pregnancy to continue to await spontaneous labour or definitive indication for delivery. However, it is not clear whether IOL in women with a previous caesarean section confers the same benefits. The aim of this study was to describe outcomes of IOL at 39-41 weeks in women with one previous caesarean delivery and to compare outcomes of IOL or planned caesarean delivery to those of expectant management.We performed a population-based retrospective cohort study of singleton births greater than 39 weeks gestation, in women with one previous caesarean delivery, in Scotland, UK 1981-2007 (n = 46,176. Outcomes included mode of delivery, perinatal mortality, neonatal unit admission, postpartum hemorrhage and uterine rupture. 40.1% (2,969/7,401 of women who underwent IOL 39-41 weeks were ultimately delivered by caesarean. When compared to expectant management IOL was associated with lower odds of caesarean delivery (adjusted odds ratio [AOR] after IOL at 39 weeks of 0.81 [95% CI 0.71-0.91]. There was no significant effect on the odds of perinatal mortality but greater odds of neonatal unit admission (AOR after IOL at 39 weeks of 1.29 [95% CI 1.08-1.55]. In contrast, when compared with expectant management, elective repeat caesarean delivery was associated with lower perinatal mortality (AOR after planned caesarean at 39 weeks of 0.23 [95% CI 0.07-0.75] and, depending on gestation, the same or lower neonatal unit admission (AOR after planned caesarean at 39 weeks of 0.98 [0.90-1.07] at 40 weeks of 1.08 [0.94-1.23] and at 41 weeks of 0.77 [0.60-1.00].A more liberal policy of IOL in women with previous caesarean delivery may reduce repeat caesarean delivery, but increases the risks of neonatal complications.

  1. NMR-based modelling and binding studies of a ternary complex between chicken liver bile acid binding protein and bile acids

    NARCIS (Netherlands)

    Tomasell, S.; Ragona, L.; Zetta, L.; Assfalg, M.; Ferranti, P.; Longhi, R.; Bonvin, A.M.J.J.; Molinari, H.

    2007-01-01

    Chicken liver bile acid binding protein (cL-BABP) is involved in bile acid transport in the liver cytosol. A detailed study of the mechanism of binding and selectivity of bile acids binding proteins towards the physiological pool of bile salts is a key issue for the complete understanding of the

  2. Studies on binding of radiolabeled thyrotropin to cultured human thyroid cells

    International Nuclear Information System (INIS)

    Yamamoto, M.; Rapoport, B.

    1978-01-01

    A line of cultured human thyroid adenoma cells was used in a study designed to compare the stimulatory effect of TSH on cellular cAMP generation with the binding of radiolabeled TSH to the cells. At 37 C, specific binding of [ 125 I]TSH to suspensions of thyroid cells was maximal at 20 min and was reversed by the addition of excess TSH. Unlike the generation of cellular cAMP in response to TSH stimulation, which was maximal at pH 7.5, the binding of [ 125 ]TSH to the cells was maximal at pH 5.5 and progressively declined up to pH 8.5. Increasing NaCl concentrations progressively inhibited cellular binding of TSH; at physiological salt concentrations, almost no TSH binding was detectable. Competitive inhibition studies of [ 125 I]TSH binding to cells revealed a binding site with a dissociation constant of 5.5 x 10 -8 M at pH 7.4. GH, PRL, hCG, FSH, insulin, and glucagon did not compete with [ 125 I)TSH binding. ACTH, however, was a potent inhibitor of [ 125 I]TSH binding. Despite this inhibitory effect on TSH binding, ACTH had little or no effect on cellular cAMP generation. High concentrations of ACTH did not inhibit the biological effect of TSH on cAMP generation. Specific binding of [ 125 I]TSH to empty plastic culture dishes was time dependent, reversible, and displayed a hormonal specificity identical to binding to thyroid cells. The effects of pH and NaCl concentrations on TSH binding to dishes were similarbut not identical to those on cellular binding. This study raises serious questions as to the biological significance of [ 125 I]TSH binding to cultured human thyroid cells

  3. Microarray study of single nucleotide polymorphisms and expression of ATP-binding cassette genes in breast tumors

    Science.gov (United States)

    Tsyganov, M. M.; Ibragimova, M. K.; Karabut, I. V.; Freydin, M. B.; Choinzonov, E. L.; Litvyakov, N. V.

    2015-11-01

    Our previous research establishes that changes of expression of the ATP-binding cassette genes family is connected with the neoadjuvant chemotherapy effect. However, the mechanism of regulation of resistance gene expression remains unclear. As many researchers believe, single nucleotide polymorphisms can be involved in this process. Thereupon, microarray analysis is used to study polymorphisms in ATP-binding cassette genes. It is thus found that MDR gene expression is connected with 5 polymorphisms, i.e. rs241432, rs241429, rs241430, rs3784867, rs59409230, which participate in the regulation of expression of own genes.

  4. Birth outcome in women with previously treated breast cancer--a population-based cohort study from Sweden.

    Directory of Open Access Journals (Sweden)

    Kristina Dalberg

    2006-09-01

    Full Text Available Data on birth outcome and offspring health after the appearance of breast cancer are limited. The aim of this study was to assess the risk of adverse birth outcomes in women previously treated for invasive breast cancer compared with the general population of mothers.Of all 2,870,932 singleton births registered in the Swedish Medical Birth Registry during 1973-2002, 331 first births following breast cancer surgery--with a mean time to pregnancy of 37 mo (range 7-163--were identified using linkage with the Swedish Cancer Registry. Logistic regression analysis was used. The estimates were adjusted for maternal age, parity, and year of delivery. Odds ratios (ORs and 95% confidence intervals (CIs were used to estimate infant health and mortality, delivery complications, the risk of preterm birth, and the rates of instrumental delivery and cesarean section. The large majority of births from women previously treated for breast cancer had no adverse events. However, births by women exposed to breast cancer were associated with an increased risk of delivery complications (OR 1.5, 95% CI 1.2-1.9, cesarean section (OR 1.3, 95% CI 1.0-1.7, very preterm birth (<32 wk (OR 3.2, 95% CI 1.7-6.0, and low birth weight (<1500 g (OR 2.9, 95% CI 1.4-5.8. A tendency towards an increased risk of malformations among the infants was seen especially in the later time period (1988-2002 (OR 2.1, 95% CI 1.2-3.7.It is reassuring that births overall were without adverse events, but our findings indicate that pregnancies in previously treated breast cancer patients should possibly be regarded as higher risk pregnancies, with consequences for their surveillance and management.

  5. DNA binding properties, histidine interaction and cytotoxicity studies of water soluble ruthenium(ii) terpyridine complexes.

    Science.gov (United States)

    Lazić, Dejan; Arsenijević, Aleksandar; Puchta, Ralph; Bugarčić, Živadin D; Rilak, Ana

    2016-03-21

    In this study, two representatives of previously synthesized ruthenium(ii) terpyridine complexes, i.e., [Ru(Cl-tpy)(en)Cl][Cl] (1) and [Ru(Cl-tpy)(dach)Cl][Cl] (2), were chosen and a detailed study of the kinetic parameters of their reactivity toward l-histidine (l-His), using the UV-Vis and (1)H NMR techniques, was developed. The inner molecular rearrangement from N3-coordinated l-His to the N1 bound isomer, observable in the NMR data, was corroborated by DFT calculations favoring N1 coordination by nearly 4 kcal mol(-1). These two ruthenium(ii) terpyridine complexes were investigated for their interactions with DNA employing UV-Vis spectroscopy, DNA viscosity measurements and fluorescence quenching measurements. The high binding constants obtained in the DNA binding studies (Kb = 10(4)-10(5) M(-1)) suggest a strong binding of the complexes to calf thymus (CT) DNA. Competitive studies with ethidium bromide (EB) showed that the complexes can displace DNA-bound EB, suggesting strong competition with EB (Ksv = 1.5-2.5 × 10(4) M(-1)). In fact, the results indicate that these complexes can bind to DNA covalently and non-covalently. In order to gain insight of the behavior of a neutral compound, besides the four previously synthesized cationic complexes [Ru(Cl-tpy)(en)Cl][Cl] (1), [Ru(Cl-tpy)(dach)Cl][Cl] (2), [Ru(Cl-tpy)(bpy)Cl][Cl] (3) and [Ru(tpy)Cl3] (P2), a new complex, [Ru(Cl-tpy)(pic)Cl] (4), was used in the biological studies. Their cytotoxicity was investigated against three different tumor cell lines, i.e., A549 (human lung carcinoma cell line), HCT116 (human colon carcinoma cell line), and CT26 (mouse colon carcinoma cell line), by the MTT assay. Complexes 1 and 2 showed higher activity than complexes 3, 4 and P2 against all the selected cell lines. The results on in vitro anticancer activity confirmed that only compounds that hydrolyze the monodentate ligand at a reasonable rate show moderate activity, provided that the chelate ligand is a hydrogen bond

  6. STUDY OF INFLUENCE OF PREVIOUS ORAL APPLICATION OF DIPHTHERIA ANTIGENIC PREPARATIONS ON RABBIT ALLERGIC REACTION FORMING AFTER SKIN TEST

    Directory of Open Access Journals (Sweden)

    Babych YeM

    2013-03-01

    Full Text Available It’s studied an influence of previous oral application of diphtheria antigenic preparations on allergic inflammation forming after skin test. It’s used destroyed by ultrasonic microbe cells C.diphtheriae var. gravis tox+ massachusets, free from destroyed cells by the use of centrifugation supernatant and refined concentrated diphteria toxoid. Experimental rabbits are fed to 3,5 ml of one of antigenic preparations (the total protein dose is 33,6 mg, control ones are fed to saline. In a week all animals were injected intracutaneously 0,2 ml each of corresponding antigenic preparation. The findings testify to decreasing manifestation tendency of rabbit skin reactions on antigenic preparations.

  7. Studies on the immune response of previously infected lambs to vaccination with the radiation attenuated Dictyocaulus filaria vaccine

    International Nuclear Information System (INIS)

    Dhar, D.N.; Sharma, R.L.

    1976-01-01

    The immune response of lambs infected with the lungworm, Dictyocaulus filaria to vaccination with the radiation attenuated D.filaria vaccine was studied under experimental conditions. Healthy, un-infected lambs, 4-6 months of age were randomly distributed into three groups. Group one lambs were previously exposed to single or trickle infections of D.filaria before being vaccinated, group two lambs were vaccinated only whereas the group three lambs received neither infection nor were vaccinated. All the lambs were subsequently challanged with normal infective D.filaria larvae. The results of the experiment indicate that the vaccine confers very little or practically no immunity in lambs already exposed to the infection. The significance of these findings in the use of the vaccine for the control of lungworm disease in sheep under field conditions is discussed. (author)

  8. The suitability of XRF analysis for compositional classification of archaeological ceramic fabric: A comparison with a previous NAA study

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, R. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Laboratorio de Analisis Quimico, Calle 30 no. 502, Playa, Ciudad Habana (Cuba)]. E-mail: roman.padilla@infomed.sld.cu; Espen, P. van [University of Antwerp (Belgium); Torres, P.P. Godo [Centro de Antropologia, Havana (Cuba)

    2006-02-03

    The main drawbacks of EDXRF techniques, restricting its more frequent use for the specific purpose of compositional analysis of archaeological ceramic fabric, have been the insufficient sensitivity to determine some important elements (like Cr, REE, among others), a somewhat worse precision and the inability to perform standard-less quantitative procedures in the absence of suitable certified reference materials (CRM) for ceramic fabric. This paper presents the advantages of combining two energy dispersive X-ray fluorescence methods for fast and non-destructive analysis of ceramic fabric with increased sensitivity. Selective polarized excitation using secondary targets (EDPXRF) and radioisotope excitation (R-XRF) using a {sup 241}Am source. The analytical performance of the methods was evaluated by analyzing several CRM of sediment type, and the fitness for the purpose of compositional classification was compared with that obtained by using Instrumental Neutron Activation Analysis in a previous study of Cuban aborigine pottery.

  9. Treatment satisfaction with paliperidone extended-release tablets: open-label study in schizophrenia patients dissatisfied with previous antipsychotic medication

    Directory of Open Access Journals (Sweden)

    Yang FD

    2017-04-01

    Full Text Available Fu De Yang,1 Juan Li,1 Yun Long Tan,1 Wei Ye Liang,1 Rongzhen Zhang,1 Ning Wang,1 Wei Feng,1 Shangli Cai,2 Jian Min Zhuo,2 Li Li Zhang2 1Beijing Hui-Long-Guan Hospital, 2Department of Medical Affairs, Xian Janssen Pharmaceutical Ltd, Beijing, People’s Republic of China Objective: The aim of this study was to evaluate the changes in treatment satisfaction after switching to paliperidone extended-release (ER in Chinese schizophrenia patients dissatisfied with their previous antipsychotic treatment.Methods: In this 8-week, open-label, single-arm, multicenter, prospective study, 1,693 patients dissatisfied with previous antipsychotic medication were enrolled and switched to paliperidone ER tablets (3–12 mg/d based on clinical judgment. The primary efficacy end point was change in Medication Satisfaction Questionnaire (MSQ score from baseline to week 8. The secondary end points included percentage of patients with MSQ score ≥4, as well as changes in Clinical Global Improvement-Severity (CGI-S and Personal and Social Performance (PSP scores.Results: MSQ scores increased significantly from baseline (mean [standard deviation {SD}]: 2.48 [0.55] to week 8 (5.47 [0.89], P<0.0001; primary end point, full analysis set. The percentage of patients with MSQ score ≥4 was 95.9% at week 8, indicating that most of the patients were satisfied with their treatment. Significant (P<0.0001 improvements from baseline to week 8 were noted in CGI-S score (2.37 [1.20] and PSP score (25.5 [15.0]. A total of 174 (10.28% patients experienced adverse events (AEs. The most common (>10 patients events were extrapyramidal disorder (n=84, 4.96%, poor quality sleep (n=18, 1.06% and akathisia (n=13, 0.77%. The majority of AEs were mild to moderate in severity. No deaths occurred.Conclusion: Treatment satisfaction improved after switching to paliperidone ER from the previous antipsychotic in Chinese patients with schizophrenia. Keywords: atypical antipsychotics, open label

  10. Evaluation of questionnaire-based information on previous physical work loads. Stockholm MUSIC 1 Study Group. Musculoskeletal Intervention Center.

    Science.gov (United States)

    Torgén, M; Winkel, J; Alfredsson, L; Kilbom, A

    1999-06-01

    The principal aim of the present study was to evaluate questionnaire-based information on past physical work loads (6-year recall). Effects of memory difficulties on reproducibility were evaluated for 82 subjects by comparing previously reported results on current work loads (test-retest procedure) with the same items recalled 6 years later. Validity was assessed by comparing self-reports in 1995, regarding work loads in 1989, with worksite measurements performed in 1989. Six-year reproducibility, calculated as weighted kappa coefficients (k(w)), varied between 0.36 and 0.86, with the highest values for proportion of the workday spent sitting and for perceived general exertion and the lowest values for trunk and neck flexion. The six-year reproducibility results were similar to previously reported test-retest results for these items; this finding indicates that memory difficulties was a minor problem. The validity of the questionnaire responses, expressed as rank correlations (r(s)) between the questionnaire responses and workplace measurements, varied between -0.16 and 0.78. The highest values were obtained for the items sitting and repetitive work, and the lowest and "unacceptable" values were for head rotation and neck flexion. Misclassification of exposure did not appear to be differential with regard to musculoskeletal symptom status, as judged by the calculated risk estimates. The validity of some of these self-administered questionnaire items appears sufficient for a crude assessment of physical work loads in the past in epidemiologic studies of the general population with predominantly low levels of exposure.

  11. Experimental strategies for studying transcription factor-DNA binding specificities.

    Science.gov (United States)

    Geertz, Marcel; Maerkl, Sebastian J

    2010-12-01

    Specific binding of transcription factors (TFs) determines in a large part the connectivity of gene regulatory networks as well as the quantitative level of gene expression. A multiplicity of both experimental and computational methods is currently used to discover and characterize the underlying TF-DNA interactions. Experimental methods can be further subdivided into in vitro- and in vivo-based approaches, each accenting different aspects of TF-binding events. In this review we summarize the flexibility and performance of a selection of both types of experimental methods. In conclusion, we argue that a serial combination of methods with different throughput and data type constitutes an optimal experimental strategy.

  12. Melanin binding study of clinical drugs with cassette dosing and rapid equilibrium dialysis inserts.

    Science.gov (United States)

    Pelkonen, Laura; Tengvall-Unadike, Unni; Ruponen, Marika; Kidron, Heidi; Del Amo, Eva M; Reinisalo, Mika; Urtti, Arto

    2017-11-15

    Melanin pigment is a negatively charged polymer found in pigmented human tissues. In the eye, iris, ciliary body, choroid and retinal pigment epithelium (RPE) are heavily pigmented. Several drug molecules are known to bind to melanin, but larger sets of drugs have not been compared often in similar test conditions. In this study, we introduce a powerful tool for screening of melanin binding. The binding of a set of 34 compounds to isolated porcine RPE melanin was determined by cassette (n-in-one) dosing in rapid equilibrium dialysis inserts and the binding was quantitated with LC-MS/MS analytics. The compounds represented large variety in melanin binding (from 8.6%, ganciclovir) to over 95% bound (ampicillin and ciprofloxacin). The data provides information on melanin binding of small molecular weight compounds that are used for ocular (e.g. brinzolamide, ganciclovir) and systemic (e.g. tizanidine, indomethacin) therapy. Interestingly, competition among compounds was seen for melanin binding and the binding did not show any correlation with plasma protein binding. These results increase the understanding of melanin binding of ocular drugs and can be further exploited to predict pharmacokinetics in the eye. Pigment binding provides an interesting option for improved drug distribution to retina and choroid that are difficult target tissues in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. A comprehensive study of oculocutaneous albinism type 1 reveals three previously unidentified alleles on the TYR gene.

    Science.gov (United States)

    Lin, Yu-Ying; Wei, Ai-Hua; He, Xin; Zhou, Zhi-Yong; Lian, Shi; Zhu, Wei

    2014-01-01

    Oculocutaneous albinism (OCA) is a congenital genetic disorder characterized by defects in melanin production. OCA type 1 (OCA1) is the most serious and common type of OCA. This study characterized mutations associated with OCA1 in a series of Chinese patients. We recruited 41 unrelated patients with OCA and 100 healthy subjects from the Chinese Han population. Genomic DNA was extracted from their blood samples. Mutational analysis of tyrosinase (TYR) genes was conducted using polymerase chain reaction (PCR) and direct sequencing, specifically to test the 100 control subjects and exclude the possibility of polymorphism. Mutational analysis and bioinformatics study were performed in TYR mutations. Among the 24 (58.5%) patients with OCA1, 21 different TYR mutations were identified, including three previously unidentified alleles (PUAs): one frameshift mutation (c.216delA) and two missense mutations (A241T and N364K). The proband mutation A241T carries three possible mutations in complex OCA. The findings of this study expand current knowledge and data of mutations associated with OCA1 in China and allow us to estimate or explore the mutation spectrum and relative frequencies of the TYR gene in the Chinese population.

  14. Barriers to postpartum screening for type 2 diabetes: a qualitative study of women with previous gestational diabetes.

    Science.gov (United States)

    Rafii, Forough; Rahimparvar, Seyedeh Fatemeh Vasegh; Mehrdad, Neda; Keramat, Afsaneh

    2017-01-01

    Risk of developing type 2 diabetes is increased in women with previous gestational diabetes mellitus (GDM). Postpartum glycemic screening is recommended in women with recent GDM. But this screening rate is low and the reasons are unclear. The aim of this study was to explore the experiences of Iranian women with recent GDM on barriers of postpartum screening for diabetes. This qualitative study was conducted in Tehran, Iran in 2016. Semi-structured interview was used for data collection. 22 women with recent GDM were interviewed. These women gave birth in Tehran hospitals at a minimum of 6 months before interview. The missed screening defined as not attending to laboratory for Fasting Blood Sugar and/or Oral Glucose Tolerance Test, 6 week to 6 month after their child birthing. The data was analyzed by content analysis method. Themes and sub-themes that illustrated the barriers to postpartum diabetes screening were: inadequate education (about developing diabetes in the future, implementation of the screening, and glucometer validity in diagnosis of diabetes), perceiving the screening as difficult (feeling comfortable with the glucometer, poor laboratory conditions, issues related to the baby/babies, and financial problems), improper attitudes toward the screening (unwilling to get diagnosed, not giving priority to oneself, having false beliefs) and procrastination (gap to intention and action, self-deception and self-regulation failure). Women with recent GDM reported several barriers for postpartum diabetes screening. This study help to develop the evidence-based interventions for improving this screening rate.

  15. Value and reliability of findings from previous epidemiologic studies in the assessment of radiation-related cancer risks. Pt. 3

    International Nuclear Information System (INIS)

    Frasch, G.; Martignoni, K.

    1990-01-01

    The theories put forward here are predominantly based on pooled data from previous studies in a number of cohorts made up by mostly non-average individuals. These studies were carried out by various researchers and differed in procedures and aims. Factors of major importance to the validity and reliability of the conclusions drawn from this study are pointed out. In one chapter some light is thrown on factors known to bear a relation to the incidence of radiation-induced cancer of the breast, even though at present this can only very vaguely be described on a quantitative basis. These factors include fractionated dose regimens, pregnancies and parturitions, menarche, menopause, synergisms as well as secondary cancer of the breast. The available body of evidence suggests that exposure of each of 1 million women to a dose of 10 mGy (rad) can be linked with approx. 3 additional cases of mammary cancer reported on an average per year after the latency period. The fact that there is some statistical scatter around this value is chiefly attributable to age-related causes at the beginning of exposure. Differences in ethnic and cultural characteristics between the populations investigated appeared to be less important here. (orig./MG) [de

  16. A Flexible-Dose Study of Paliperidone ER in Patients With Nonacute Schizophrenia Previously Treated Unsuccessfully With Oral Olanzapine

    Science.gov (United States)

    KOTLER, MOSHE; DILBAZ, NESRIN; ROSA, FERNANDA; PATERAKIS, PERIKLIS; MILANOVA, VIHRA; SMULEVICH, ANATOLY B.; LAHAYE, MARJOLEIN

    2016-01-01

    Objective: The goal of this study was to explore the tolerability, safety, and treatment response of switching from oral olanzapine to paliperidone extended release (ER). Methods: Adult patients with nonacute schizophrenia who had been treated unsuccessfully with oral olanzapine were switched to flexible doses of paliperidone ER (3 to 12 mg/d). The primary efficacy outcome was a ≥20% improvement in Positive and Negative Syndrome Scale (PANSS) total scores from baseline to endpoint for patients who switched medications because of lack of efficacy with olanzapine and noninferiority versus previous olanzapine treatment (mean endpoint change in PANSS total scores vs. baseline of ≤5 points) for patients who switched for reasons other than lack of efficacy. Safety and tolerability were assessed by monitoring adverse events, extrapyramidal symptoms, and weight change. Results: Of 396 patients, 65.2% were men, mean age was 40.0±12.0 years, and 75.5% had paranoid schizophrenia. Among the patients whose main reason for switching was lack of efficacy, an improvement in the PANSS total score of ≥20% occurred in 57.4% of patients. Noninferiority was confirmed for each subgroup of patients whose main reason for switching was something other than lack of efficacy. Paliperidone ER was generally well tolerated. Extrapyramidal symptoms as measured by total Extrapyramidal Symptom Rating Scale scores showed statistically significant and clinically relevant improvements at endpoint, the average weight decreased by 0.8±5.2 kg at endpoint, and a clinically relevant weight gain of ≥7% occurred in 8.0% of patients. Conclusion: Paliperidone ER flexibly-dosed over 6 months was well tolerated and associated with a meaningful clinical response in patients with nonacute schizophrenia who had previously been unsuccessfully treated with oral olanzapine. PMID:26813484

  17. A Flexible-Dose Study of Paliperidone ER in Patients With Nonacute Schizophrenia Previously Treated Unsuccessfully With Oral Olanzapine.

    Science.gov (United States)

    Kotler, Moshe; Dilbaz, Nesrin; Rosa, Fernanda; Paterakis, Periklis; Milanova, Vihra; Smulevich, Anatoly B; Lahaye, Marjolein; Schreiner, Andreas

    2016-01-01

    The goal of this study was to explore the tolerability, safety, and treatment response of switching from oral olanzapine to paliperidone extended release (ER). Adult patients with nonacute schizophrenia who had been treated unsuccessfully with oral olanzapine were switched to flexible doses of paliperidone ER (3 to 12 mg/d). The primary efficacy outcome was a ≥ 20% improvement in Positive and Negative Syndrome Scale (PANSS) total scores from baseline to endpoint for patients who switched medications because of lack of efficacy with olanzapine and noninferiority versus previous olanzapine treatment (mean endpoint change in PANSS total scores vs. baseline of ≤ 5 points) for patients who switched for reasons other than lack of efficacy. Safety and tolerability were assessed by monitoring adverse events, extrapyramidal symptoms, and weight change. Of 396 patients, 65.2% were men, mean age was 40.0 ± 12.0 years, and 75.5% had paranoid schizophrenia. Among the patients whose main reason for switching was lack of efficacy, an improvement in the PANSS total score of ≥ 20% occurred in 57.4% of patients. Noninferiority was confirmed for each subgroup of patients whose main reason for switching was something other than lack of efficacy. Paliperidone ER was generally well tolerated. Extrapyramidal symptoms as measured by total Extrapyramidal Symptom Rating Scale scores showed statistically significant and clinically relevant improvements at endpoint, the average weight decreased by 0.8 ± 5.2 kg at endpoint, and a clinically relevant weight gain of ≥ 7% occurred in 8.0% of patients. Paliperidone ER flexibly-dosed over 6 months was well tolerated and associated with a meaningful clinical response in patients with nonacute schizophrenia who had previously been unsuccessfully treated with oral olanzapine.

  18. Polyethyleneimine anchored copper(II) complexes: synthesis, characterization, in vitro DNA binding studies and cytotoxicity studies.

    Science.gov (United States)

    Lakshmipraba, Jagadeesan; Arunachalam, Sankaralingam; Riyasdeen, Anvarbatcha; Dhivya, Rajakumar; Akbarsha, Mohammad Abdulkader

    2015-01-01

    The water soluble polyethyleneimine-copper(II) complexes, [Cu(phen)(L-tyr)BPEI]ClO4 (where phen=1,10-phenanthroline, L-tyr=L-tyrosine and BPEI=branched polyethyleneimine) with various degree of copper(II) complex units in the polymer chain were synthesized and characterized by elemental analysis and electronic, FT-IR, EPR spectroscopic techniques. The binding of these complexes with CT-DNA was studied using UV-visible absorption titration, thermal denaturation, emission, circular dichroism spectroscopy and cyclic voltammetric methods. The changes observed in the physicochemcial properties indicated that the binding between the polymer-copper complexes and DNA was mostly through electrostatic mode of binding. Among these complexes, the polymer-copper(II) complex with the highest degrees of copper(II) complex units (higher degrees of coordination) showed higher binding constant than those with lower copper(II) complex units (lower degrees of coordination) complexes. The complex with the highest number of metal centre bound strongly due to the cooperative binding effect. Therefore, anticancer study was carried out using this complex. The cytotoxic activity for this complex on MCF-7 breast cancer cell line was determined adopting MTT assay, acridine orange/ethidium bromide (AO/EB) staining and comet assay techniques, which revealed that the cells were committed to specific mode of cell death either apoptosis or necrosis. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Binding of ciprofloxacin by humic substances: a molecular dynamics study.

    Science.gov (United States)

    Aristilde, Ludmilla; Sposito, Garrison

    2010-01-01

    A comprehensive assessment of the potential impacts of antimicrobials released into the environment requires an understanding of their sequestration by natural particles. Of particular interest are the strong interactions of antimicrobials with natural organic matter (NOM), which are believed to reduce their bioavailability, retard their abiotic and biotic degradation, and facilitate their persistence in soils and aquatic sediments. Molecular dynamics (MD) relaxation studies of a widely used fluoroquinolone antibiotic, ciprofloxacin (Cipro), interacting with a model humic substance (HS) in a hydrated environment, were performed to elucidate the mechanisms of these interactions. Specifically, a zwitterionic Cipro molecule, the predominant species at circumneutral pH, was reacted either with protonated HS or deprotonated HS bearing Ca, Mg, or Fe(II) cations. The HS underwent conformational changes through rearrangements of its hydrophobic and hydrophilic regions and disruption of its intramolecular H-bonds to facilitate favorable intermolecular H-bonding interactions with Cipro. Complexation of the metal cations with HS carboxylates appeared to impede binding of the positively charged amino group of Cipro with these negatively charged HS complexation sites. On the other hand, an outer-sphere complex between Cipro and the HS-bound cation led to ternary Cipro-metal-HS complexes in the case of Mg-HS and Fe(II)-HS, but no such bridging interaction occurred with Ca-HS. The results suggested that the ionic potential (valence/ionic radius) of the divalent cation may be a determining factor in the formation of the ternary complex, with high ionic potential favoring the bridging interaction. Environ. Toxicol. Chem. 2010;29:90-98. (c) 2009 SETAC.

  20. Studies on folate binding and a radioassay for serum and whole blood folate using goat milk as binding agent

    International Nuclear Information System (INIS)

    Piyasena, R.D.; Weerasekera, D.A.; Hettiaratchi, N.; Wikramanayake, T.W.; Sri Lanka Univ., Peradeniya Campus. Nuclear Medicine Unit)

    1977-01-01

    Preparations of cow, goat, buffalo, and human milk in addition to pig plasma were tested for folate binding properties. Of these, only pig plasma and goat milk showed sufficient binding to enable use as binding agents in a radioassay for serum and whole blood folate. The binding of folate by cow mild preparations in particular was found to be very poor. (orig.) [de

  1. Study of Binding between Protein A and Immunoglobulin G Using a Surface Tension Probe

    OpenAIRE

    Yang, L.; Biswas, M. E.; Chen, P.

    2003-01-01

    Molecular interactions and binding are one of the most important and fundamental properties in the study of biochemical and biomedical systems. The understanding of such interactions and binding among biomolecules forms the basis for the design and processing of many biotechnological applications, such as bioseparation and immunoadsorption. In this study, we present a novel method to probe molecular interactions and binding based on surface tension measurement. This method complements convent...

  2. Fluorescence spectroscopic studies on binding of a flavonoid ...

    Indian Academy of Sciences (India)

    Unknown

    Human serum albumin; bovine serum albumin; quercetin; energy transfer; binding constant. 1. Introduction. Serum albumins are abundantly found in blood plasma and are often termed transport proteins.1–4 They are circulated in the body several times and act as carri- ers for numerous exogenous and endogenous com-.

  3. Substance P: binding properties and studies on cellular responses in guinea pig macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Hartung, H.P.; Wolters, K.; Toyka, K.V.

    1986-05-15

    The neuropeptide Substance P (SP) has been recognized to modulate functional activities of inflammatory cells. The authors have previously shown that it mediates macrophage activation. In this study they examined binding characteristics of SP and searched for additional evidence of heightened metabolic activity of guinea pig peritoneal macrophages upon challenge with this peptide. Radioligand studies indicated the existence of a homogeneous class of specific binding sites with high affinity for SP on macrophages. Scatchard analysis yielded an apparent K/sub D/ of 1.9 +/- 0.4 x 10/sup -8/ M (range: 1.4 to 2.4 x 10/sup -8/ M), which was confirmed by kinetic studies. Binding was dose related, saturable, reversible, and could be inhibited by the SP antagonist (D-Pro/sup 2/, D-Phe/sup 7/, D-Trp/sup 9/)-SP. Examination of peptide structural requirements revealed that both the COOH- and NH/sub 2/-terminus contribute to receptor-ligand interaction. Other members of the tachykinin group of peptides were devoid of stimulatory action on macrophages. Cellular responses after engagement of the receptor sites by SP included downregulation of the membrane-associated enzyme 5'-nucleotidase and stimulation of synthesis and release of arachidonic acid metabolites, as well as of the lysosomal enzyme ADGase. These actions were specific as evidenced by immunoabsorption experiments. The findings demonstrate that macrophage activation afforded by SP is effected through a receptor-mediated mechanism. Liberation of proinflammatory and immunomodulating substances in response to SP may be relevant to the pathogenesis of neuroinflammatory disease.

  4. Synthesis, Characterization, and Saccharide Binding Studies of Bile Acid − Porphyrin Conjugates

    Directory of Open Access Journals (Sweden)

    Vladimír Král

    2007-01-01

    Full Text Available Synthesis and characterization of bile acid-porphyrin conjugates (BAPs are reported. Binding of saccharides with BAPs in aqueous methanol was studied by monitoring changes in the visible absorption spectral of the porphyrin-moieties. Although these studies clearly showed absorbance changes, suggesting quite high if non-selective binding, the mass spectral studies do not unambiguously support these results.

  5. Patterns and Determinants of Treatment Seeking among Previously Untreated Psychotic Patients in Aceh Province, Indonesia: A Qualitative Study

    Directory of Open Access Journals (Sweden)

    Marthoenis Marthoenis

    2016-01-01

    Full Text Available Immediate treatment of first-episode psychosis is essential in order to achieve a positive outcome. However, Indonesian psychiatric patients often delay accessing health services, the reason for which is not yet fully understood. The current study aimed to understand patterns of treatment seeking and to reveal determinants of the delay in accessing psychiatric care among first-time user psychotic patients. Qualitative interviews were conducted with sixteen family members who accompanied the patients to a psychiatric hospital. Many families expressed beliefs that mental illness appertains to village sickness and not hospital sickness; therefore, they usually take the patients to traditional or religious healers before taking them to a health professional. They also identified various factors that potentially delay accessing psychiatric treatment: low literacy and beliefs about the cause of the illness, stigmatisation, the role of extended family, financial problems, and long distance to the psychiatric hospital. On the other hand, the family mentioned various factors related to timely help seeking, including being a well-educated family, living closer to health facilities, previous experience of successful psychotic therapy, and having more positive symptoms of psychosis. The findings call for mental health awareness campaigns in the community.

  6. Pilot Study of an Individualised Early Postpartum Intervention to Increase Physical Activity in Women with Previous Gestational Diabetes

    Directory of Open Access Journals (Sweden)

    Harold David McIntyre

    2012-01-01

    Full Text Available Optimal strategies to prevent progression towards overt diabetes in women with recent gestational diabetes remain ill defined. We report a pilot study of a convenient, home based exercise program with telephone support, suited to the early post-partum period. Twenty eight women with recent gestational diabetes were enrolled at six weeks post-partum into a 12 week randomised controlled trial of Usual Care (n=13 versus Supported Care (individualised exercise program with regular telephone support; n=15. Baseline characteristics (Mean ± SD were: Age  33±4  years; Weight 80 ± 20 kg and Body Mass Index (BMI 30.0±9.7 kg/m2. The primary outcome, planned physical activity {Median (Range}, increased by 60 (0–540 mins/week in the SC group versus 0 (0–580 mins/week in the UC group (P=0.234. Walking was the predominant physical activity. Body weight, BMI, waist circumference, % body fat, fasting glucose and insulin did not change significantly over time in either group. This intervention designed to increase physical activity in post-partum women with previous gestational diabetes proved feasible. However, no measurable improvement in metabolic or biometric parameters was observed over a three month period.

  7. Tamoxifen and curcumin binding to serum albumin. Spectroscopic study

    Science.gov (United States)

    Maciążek-Jurczyk, M.; Maliszewska, M.; Pożycka, J.; Równicka-Zubik, J.; Góra, A.; Sułkowska, A.

    2013-07-01

    Tamoxifen (TMX) is widely used for the breast cancer treatment and is known as chemopreventive agent. Curcumin (CUR) is natural phenolic compound with broad spectrum of biological activity e.g. anti-inflammatory, antimicrobial, antiviral, antifungal and chemopreventive. Combination of tamoxifen and curcumin could be more effective with lower toxicity than each agent alone in use for the treatment or chemoprevention of breast cancer. Binding of drugs to serum albumin is an important factor, which determines toxicity and therapeutic dosage of the drugs. When two drugs are administered together the competition between them for the binding site on albumin can result in a decrease in bound fraction and an increase in the concentration of free biologically active fraction of drug.

  8. Using a pregnancy decision support program for women choosing birth after a previous caesarean in Japan: A mixed methods study.

    Science.gov (United States)

    Torigoe, Ikuyo; Shorten, Allison

    2018-02-01

    Opportunities for women and providers to use decision aids and share decisions about birth after caesarean in practice are currently limited in Japan. This is despite known benefits of decision aids to support value-sensitive healthcare decisions. To explore Japanese women's decision making experiences using a decision aid program for birth choices after caesarean. A mixed methods study was conducted among 33 consenting pregnant women with previous caesarean in five obstetrics institutions located in the western part of Japan. Outcome measures included change in level of decisional conflict, change in knowledge, and preference for birth method. Semi-structured interviews examined women's decision making experiences, and qualitative data were analyzed using thematic analysis. The participants in the program experienced a statistically significant improvement in knowledge and reduction in decisional conflict about birth after caesarean. Four themes were identified in the qualitative data related to decision making: change in women's knowledge about birth choices, clarifying women's birth preference, feelings about shared decision making, and contrasting feelings after receiving information. This study confirmed potential benefits of using the decision aid program. However, uncertainty about mode of birth continued for some women immediately prior to the birth. This finding emphasized the need to identify additional ways to support women emotionally throughout the process of decision making about birth after caesarean. It was feasible to adapt the decision aid for use in clinical practice. Future research is necessary to examine its effectiveness when implemented in Japanese clinical settings. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  9. Structural study of LEDGF/p75 binding partners

    Czech Academy of Sciences Publication Activity Database

    Těšina, Petr; Čermáková, Kateřina; Procházková, Kateřina; Hořejší, Magdalena; Christ, F.; De Rijck, J.; Veverka, Václav; Řezáčová, Pavlína

    2013-01-01

    Roč. 20, č. 1 (2013), s. 12-12 ISSN 1211-5894. [Discussions in Structural Molecular Biology. Annual Meeting of the Czech Society for Structural Biology /11./. 14.03.2013-16.03.2013, Nové Hrady] R&D Projects: GA MŠk(CZ) LK11205 Institutional support: RVO:61388963 ; RVO:68378050 Keywords : LEDGF/p75 * HIV * integrase-binding domain Subject RIV: EB - Genetics ; Molecular Biology

  10. EPR studies of cooperative binding of Cu (II) to hemoglobin

    International Nuclear Information System (INIS)

    Louro, S.R.W.; Tabak, M.

    1983-07-01

    The investigation of the relative affinities of the two pairs of hemoglobin copper sites by monitoring the EPR spectra of the complexes formed by the reaction of copper with deoxyhemoglobin is reported. A model in which two sites are assumed to accept copper ions in a noncooperative way is not able to predict the experimental results. Thus it is conclude that the binding of these ions to hemoglobin is a cooperative phenomenon. (Author) [pt

  11. A molecular dynamics study of human serum albumin binding sites.

    Science.gov (United States)

    Artali, Roberto; Bombieri, Gabriella; Calabi, Luisella; Del Pra, Antonio

    2005-01-01

    A 2.0 ns unrestrained Molecular Dynamics was used to elucidate the geometric and dynamic properties of the HSA binding sites. The structure is not stress affected and the rmsds calculated from the published crystallographic data are almost constant for all the simulation time, with an averaged value of 2.4A. The major variability is in the C-terminus region. The trajectory analysis of the IIA binding site put in evidence fast oscillations for the Cgamma@Leu203...Cgamma@Leu275 and Cgamma@Leu219...Cgamma@Leu260 distances, with fluctuations around 250 ps, 1000 ps and over for the first, while the second is smoothly increasing with the simulation time from 7 to 10A. These variations are consistent with a volume increase up to 20% confirmed by the inter-domain contacts analysis, in particular for the pair O@Pro148...Ogamma@Ser283, representing the change of distance between IB-h9 and IIA-h6, O@Glu149...Ogamma@Ser189 for sub-domains IB-h9/IIA-h1 and N@Val339...Odelta2@Asp447 sub-domains IIB-h9/IIIA-h1. These inter-domain motions confirm the flexibility of the unfatted HSA with possible binding site pre-formation.

  12. The binding study advice in medical education: a 2-year experience.

    NARCIS (Netherlands)

    Eijsvogels, T.M.H.; Goorden, R.; Bosch, W.J.H.M. van den; Hopman, M.T.E.

    2015-01-01

    To improve the effectiveness of higher education, Dutch universities implemented the binding study advice at medical faculties. Accordingly, medicine students of Radboud University need to gain >/= 42 out of 60 European Credit Transfer System (ECTS) credits to obtain a positive binding study advice

  13. Crystallographic study of novel transthyretin ligands exhibiting negative-cooperativity between two thyroxine binding sites.

    Directory of Open Access Journals (Sweden)

    Divya Tomar

    Full Text Available BACKGROUND: Transthyretin (TTR is a homotetrameric serum and cerebrospinal fluid protein that transports thyroxine (T4 and retinol by binding to retinol binding protein. Rate-limiting tetramer dissociation and rapid monomer misfolding and disassembly of TTR lead to amyloid fibril formation in different tissues causing various amyloid diseases. Based on the current understanding of the pathogenesis of TTR amyloidosis, it is considered that the inhibition of amyloid fibril formation by stabilization of TTR in native tetrameric form is a viable approach for the treatment of TTR amyloidosis. METHODOLOGY AND PRINCIPAL FINDINGS: We have examined interactions of the wtTTR with a series of compounds containing various substitutions at biphenyl ether skeleton and a novel compound, previously evaluated for binding and inhibiting tetramer dissociation, by x-ray crystallographic approach. High resolution crystal structures of five ligands in complex with wtTTR provided snapshots of negatively cooperative binding of ligands in two T4 binding sites besides characterizing their binding orientations, conformations, and interactions with binding site residues. In all complexes, the ligand has better fit and more potent interactions in first T4 site i.e. (AC site than the second T4 site (BD site. Together, these results suggest that AC site is a preferred ligand binding site and retention of ordered water molecules between the dimer interfaces further stabilizes the tetramer by bridging a hydrogen bond interaction between Ser117 and its symmetric copy. CONCLUSION: Novel biphenyl ether based compounds exhibit negative-cooperativity while binding to two T4 sites which suggests that binding of only single ligand molecule is sufficient to inhibit the TTR tetramer dissociation.

  14. The binding study advice in medical education: a 2-year experience.

    Science.gov (United States)

    Eijsvogels, Thijs M H; Goorden, Ronald; van den Bosch, Wil; Hopman, Maria T E

    2015-02-01

    To improve the effectiveness of higher education, Dutch universities implemented the binding study advice at medical faculties. Accordingly, medicine students of Radboud University need to gain ≥ 42 out of 60 European Credit Transfer System (ECTS) credits to obtain a positive binding study advice and to continue their study programme. In case of a negative advice, the student is obliged to terminate the study, and he/she cannot register for the same study programme in the Netherlands within the next three years. The purpose of this manuscript is to evaluate the effect of implementation of the binding study advice on study outcomes. First, the binding study advice did not impact on student performance, as the average ECTS credits were comparable before and after its introduction. Second, study progress improved 8 % with 93 % of the students obtaining access to the second year of the study programme after binding study advice implementation. Third, the binding study advice did not impact propaedeutic graduation rates. These data demonstrate that the implementation of the binding study advice in medical faculties has only a small impact on study outcomes. The high performance levels of medical students compared with peers at other faculties are likely to contribute to these findings and suggest a 'ceiling effect' in the potential improvement of study outcomes at medical faculties.

  15. Discovery of previously undetected intellectual disability by psychological assessment: a study of consecutively referred child and adolescent psychiatric inpatients.

    Science.gov (United States)

    Pogge, David L; Stokes, John; Buccolo, Martin L; Pappalardo, Stephen; Harvey, Philip D

    2014-07-01

    Intellectual disability is associated with an increased risk of behavioral disturbances and also complicates their treatment. Despite increases in the sophistication of medical detection of early risk for intellectual disability, there is remarkably little data about the detection of intellectual disability in cases referred for psychiatric treatment. In this study, we used a 10-year sample of 23,629 consecutive child and adolescent admissions (ages between 6 and 17) to inpatient psychiatric treatment. Eleven percent (n=2621) of these cases were referred for psychological assessment and were examined with a general measure of intellectual functioning (i.e., WISC-IV). Of these cases, 16% had Full Scale IQs below 70. Of the cases whose therapists then referred them for formal assessment of their adaptive functioning (i.e., ABAS-II) 81% were found to have composite scores below 70 as well. Only one of the cases whose Full Scale IQ was less than 70 had a referral diagnosis of intellectual disability. Cases with previously undetected intellectual disability were found to be significantly more likely to have a diagnosis of a psychotic disorder and less likely to have a diagnosis of mood disorder than cases with IQs over 70. Disruptive behavior disorder diagnoses did not differ as a function of intellectual performance. These data suggest a high rate of undetected intellectual disability in cases with a psychiatric condition serious enough to require hospitalization and this raises the possibility that many such cases may be misdiagnosed, the basis of their problems may be misconceptualized, and they may be receiving treatments that do not take into account their intellectual level. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. DNA-cisplatin binding mechanism peculiarities studied with single molecule stretching experiments

    Science.gov (United States)

    Crisafuli, F. A. P.; Cesconetto, E. C.; Ramos, E. B.; Rocha, M. S.

    2012-02-01

    We propose a method to determine the DNA-cisplatin binding mechanism peculiarities by monitoring the mechanical properties of these complexes. To accomplish this task, we have performed single molecule stretching experiments by using optical tweezers, from which the persistence and contour lengths of the complexes can be promptly measured. The persistence length of the complexes as a function of the drug total concentration in the sample was used to deduce the binding data, from which we show that cisplatin binds cooperatively to the DNA molecule, a point which so far has not been stressed in binding equilibrium studies of this ligand.

  17. Associations of obesity with newly diagnosed and previously known atopic diseases in Chinese adults: a case-control study

    OpenAIRE

    Xie, Biao; Wang, Zhiqiang; Wang, Yupeng; Liu, Meina; Wang, Yongchen

    2017-01-01

    To assess the associations of obesity with newly diagnosed and previously known atopic disorders in Chinese adults. 4,629 adults aged 18 years or older were recruited in Harbin, China. Among them, 1,114 were previously diagnosed atopic cases, 1,298 were newly diagnosed cases, and 2,217 non-atopic controls. Obesity and overweight are defined according to the criteria established by the Working Group on Obesity in China. The associations of obesity with known and newly diagnosed atopic disorder...

  18. Binding of DNA-binding alkaloids berberine and palmatine to tRNA and comparison to ethidium: Spectroscopic and molecular modeling studies

    Science.gov (United States)

    Islam, Md. Maidul; Pandya, Prateek; Chowdhury, Sebanti Roy; Kumar, Surat; Kumar, Gopinatha Suresh

    2008-11-01

    The interaction of two natural protoberberine plant alkaloids berberine and palmatine with tRNA phe was studied using various biophysical techniques and molecular modeling and the data were compared with the binding of the classical DNA intercalator, ethidium. Circular dichroic studies revealed that the tRNA conformation was moderately perturbed on binding of the alkaloids. The cooperative binding of both the alkaloids and ethidium to tRNA was revealed from absorbance and fluorescence studies. Fluorescence quenching studies advanced a conclusion that while berberine and palmatine are partially intercalated, ethidium is fully intercalated on the tRNA molecule. The binding of the alkaloids as well as ethidium stabilized the tRNA melting, and the binding constant evaluated from the averaged optical melting temperature data was in agreement with fluorescence spectral-binding data. Differential scanning calorimetry revealed that the tRNA melting showed three close transitions that were affected on binding of these small molecules. Molecular docking calculations performed showed the preferred regions of binding of these small molecules on the tRNA. Taken together, the results suggest that the binding of the alkaloids berberine and palmatine on the tRNA structure appears to be mostly by partial intercalation while ethidium intercalates fully on the tRNA. These results further advance our knowledge on the molecular aspects on the interaction of these alkaloids to tRNA.

  19. Synthesis, Crystal Structure and in vitro DNA Binding Studies of Combretastatin A-4 Analogue

    Directory of Open Access Journals (Sweden)

    Masood Ahmad Rizvi

    2015-12-01

    Full Text Available Synthesis of a novel Combretastatin A-4 analogue using Schiff’s reaction of benzil and 4-aminoantipyrine has been achieved under solvent free conditions. The structure of compound was examined spectroscopically and confirmed from single crystal diffraction studies. The synthesized Combretastatin A-4 analogue was investigated for its DNA binding ability as the plausible mechanism for its antitumor activity. The binding propensity of the synthesized compound with calf-thymus (CT DNA was monitored with absorption and emission spectrophotometric titrations. The calculations predict a binding constant of 7.24×104 for the complex of the synthesized compound with CT DNA which is comparable in magnitude to that of DNA binding of bactericidal drug enoxacin and typical intercalation indicator ethidium bromide (EB. Competitive binding studies of the synthesized compound with EB using fluorescence titration reveal that it displaces the DNA-bound EB and binds in intercalative mode which was further supported by circular dichroism (CD spectroscopy. The probable site and binding energy of the compound with DNA was further theoretically investigated by molecular docking studies. The significant DNA binding ability of the synthesized Combretastatin A4 analogue as revealed from this study could be related to the anticancer activity of the Combretastatin A4.

  20. Laparoscopy After Previous Laparotomy

    Directory of Open Access Journals (Sweden)

    Zulfo Godinjak

    2006-11-01

    Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.

  1. Phenylbutazone and ketoprofen binding to serum albumin. Fluorescence study.

    Science.gov (United States)

    Maciążek-Jurczyk, Małgorzata

    2014-10-01

    A combination of phenylbutazone (PBZ) and ketoprofen (KP) is popular in therapy of rheumatoid arthritis (RA) but could be unsafe due to the uncontrolled growth of toxicity. Quenching fluorescence of serum albumin in the presence of the both drugs has been characterized by dynamic KQ [M(-1)], static V [M(-1)] quenching constants and also association constants Ka [M(-1)]. The quenching of tryptophanyl residues fluorescence by the KP and PBZ indicates the capability of these drugs to accept the energy from Trp-214 and Trp-135. Strong displacement of KP and PBZ bound to albumin cause by the binding of the second drug to SA close to Trp-214 (subdomain IIA) has been obtained. The displacement was also confirmed on the basis of quenching and association constants. The conclusion, that both PBZ and KP form a binding site in the same subdomains (IIA or/and IB), points to the necessity of using a monitoring therapy owning to the possible increase of the uncontrolled toxic effects. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  2. Associations of obesity with newly diagnosed and previously known atopic diseases in Chinese adults: a case-control study.

    Science.gov (United States)

    Xie, Biao; Wang, Zhiqiang; Wang, Yupeng; Liu, Meina; Wang, Yongchen

    2017-03-02

    To assess the associations of obesity with newly diagnosed and previously known atopic disorders in Chinese adults. 4,629 adults aged 18 years or older were recruited in Harbin, China. Among them, 1,114 were previously diagnosed atopic cases, 1,298 were newly diagnosed cases, and 2,217 non-atopic controls. Obesity and overweight are defined according to the criteria established by the Working Group on Obesity in China. The associations of obesity with known and newly diagnosed atopic disorders were assessed using logistic regressions. Obesity was significantly associated with known atopic disorders (adjusted OR = 2.41 (95% CI: 1.81, 3.22)). The association of obesity with newly diagnosed atopic cases was not as strong as that with known cases, and was not statistically significant (adjusted OR = 1.27 (95% CI: 0.94, 1.72)). The similar pattern was observed in different allergic diseases, gender and age stratifications. The association between overweight and atopic diseases were not significant. Obesity is strongly associated with previously diagnosed atopic cases but not so with newly diagnosed atopic cases in Chinese adults. It is likely that people with atopic disorders have a higher risk of developing obesity. Our findings are important for the management of atopic disorders and chronic disease prevention among atopic disease patients.

  3. Radioimmunotherapy with Y-90-epratuzumab in patients with previously treated B-cell lymphoma. A fractionated dose-escalation study

    International Nuclear Information System (INIS)

    Linden, O.; Cavallin-Stahl, E.; Tennvall, J.; Hindorf, C.; Olsson, T.; Strand, S.E.; Stenberg, L.; Wingardh, K.

    2002-01-01

    Aim: Fractionated RIT may improve outcome by decreasing heterogeneity in absorbed dose and by increasing therapeutic window. The humanised anti-CD22 antibody, Epratuzumab, (Immunomedics, Inc., Morris Plains, NJ) can be given repeatedly with minimal risk of neutralising Ab (HAHA), making fractionated treatment with 90 Y-labelled epratuzumab possible. Materials and Methods: Patients with previously treated B-cell lymphoma received increasing number (2-4) of weekly infusions of 90 Y-epratuzumab. Patients received either 185 MBq/m 2 per infusion (group A), or, if they had a history of high-dose chemotherapy with stem-cell rescue, 92.5 MBq/m 2 per infusion (group B). The first infusion included 150 MBq of 111 Indium for scintigraphic verification of tumour targeting and dosimetry. 1.5 mg/kg epratuzumab was administered with each infusion. The treatment could be repeated once after 3 m. Results: Of 23 patients, 16 in group A and 6 in group B were evaluable for response. The RR in group A was 62% objective response (OR) and 25% CR/CRu. One patient in group B showed OR. OR was seen in aggressive and indolent lymphoma. Response was also long-lasting and event-free survival of patients showing CR/CRu was 14 to 25+ months. In group A all seven patient, receiving three infusions, showed less than grade 3 platelet and neutrophil toxicity, except for two patients suffering grade 3 neutropenia. Of five patients with 4 weekly infusions there were two patients with dose-limiting haematological toxicity (DLT), both recently treated with high dose cytosar before RIT. With criteria used the maximal tolerated dose was three infusions 185 MBq/m 2 . In group B no patient suffered DLT and one patient exhibited OR. Seven patients were retreated after 3 months with minor toxicity, but improvement in OR in two cases. No patient has developed HAHA. CD22 expression on tumour cells, as assessed by flow cytometry, is available in 18 of 22 patients. In group A, seven of eight patients with

  4. Dielectric and gravimetric studies of water binding to lysozyme

    International Nuclear Information System (INIS)

    Bone, S.

    1996-01-01

    Time domain dielectric spectroscopy and hydration isotherm measurements as a function of temperature have been applied to hydrated lysozyme powder. Two dielectric dispersions were identified, the first centred at approximately 8 MHz and a second above 1 GHz. The higher dispersion is considered to be the result of rotational relaxation of water molecules bound to the enzyme. In this case the results indicate the existence of a population of 32 water molecules per lysozyme molecule which are irrotationally bound to the lysozyme structure. A larger population of water molecules is relatively free to respond to the electric field and exhibits a dipole moment close to that of vapour phase water molecules. Multi-temperature hydration isotherm measurements are used to calculate enthalpies and entropies associated with the binding of water to lysozyme. Discontinuities both in dielectric and in thermodynamic characteristics in the range 10-14% hydration are interpreted as a re-ordering of the water structure on the enzyme surface

  5. Binding mode analyses of NAP derivatives as mu opioid receptor selective ligands through docking studies and molecular dynamics simulation.

    Science.gov (United States)

    Wang, Huiqun; Zaidi, Saheem A; Zhang, Yan

    2017-04-15

    Mu opioid receptor selective antagonists are highly desirable because of their utility as pharmacological probes for receptor characterization and functional studies. Furthermore, the mu opioid receptors act as an important target in drug abuse and addiction treatment. Previously, we reported NAP as a novel lead compound with high selectivity and affinity towards the mu opioid receptor. Based on NAP, we have synthesized its derivatives and further characterized their binding affinities and selectivity towards the receptor. NMP and NGP were identified as the two most selective MOR ligands among NAP derivatives. In the present study, molecular modeling methods were applied to assess the dual binding modes of NAP derivatives, particularly on NMP and NGP, in three opioid receptors, in order to analyze the effects of structural modifications on the pyridyl ring of NAP on the binding affinity and selectivity. The results indicated that the steric hindrance, electrostatic, and hydrophobic effects caused by the substituents on the pyridyl ring of NAP contributed complimentarily on the binding affinity and selectivity of NAP derivatives to three opioid receptors. Analyses of these contributions provided insights on future design of more potent and selective mu opioid receptor ligands. Published by Elsevier Ltd.

  6. Long-term stability study of Prussian blue - a quality assessment of water content and thallium binding.

    Science.gov (United States)

    Mohammad, Adil; Faustino, Patrick J; Khan, Mansoor A; Yang, Yongsheng

    2014-12-30

    loss of PB and pH conditions are consistent with our previously published data. The study also represents the first quantitative assessment of the long-term stability of PB. Over last 10 years, PB DPs and APIs have lost about 20% water under ambient laboratory storage conditions which are consistent with a controlled warehouse environment. While the maximum binding capacity of PB to thallium was decreased after about 10 years of long-term storage, it is still very effective, suggesting that the shelf life of PB should be much longer than the manufacturer ascribed expiration date of 2008 under proper storage conditions. Published by Elsevier B.V.

  7. QM/MM Molecular Dynamics Studies of Metal Binding Proteins

    Directory of Open Access Journals (Sweden)

    Pietro Vidossich

    2014-07-01

    Full Text Available Mixed quantum-classical (quantum mechanical/molecular mechanical (QM/MM simulations have strongly contributed to providing insights into the understanding of several structural and mechanistic aspects of biological molecules. They played a particularly important role in metal binding proteins, where the electronic effects of transition metals have to be explicitly taken into account for the correct representation of the underlying biochemical process. In this review, after a brief description of the basic concepts of the QM/MM method, we provide an overview of its capabilities using selected examples taken from our work. Specifically, we will focus on heme peroxidases, metallo-β-lactamases, α-synuclein and ligase ribozymes to show how this approach is capable of describing the catalytic and/or structural role played by transition (Fe, Zn or Cu and main group (Mg metals. Applications will reveal how metal ions influence the formation and reduction of high redox intermediates in catalytic cycles and enhance drug metabolism, amyloidogenic aggregate formation and nucleic acid synthesis. In turn, it will become manifest that the protein frame directs and modulates the properties and reactivity of the metal ions.

  8. Structure/Function Studies of the Androgen Receptor DNA-Binding Region

    National Research Council Canada - National Science Library

    Rastinejad, Fraydoon

    2004-01-01

    .... The research goals associated with this study are to characterize the structural and functional aspects of the AR in order to uncover the potential of its domains, and in particular the DNA-binding...

  9. Structure/Function Studies of the Androgen Receptor DNA-Binding Region

    National Research Council Canada - National Science Library

    Rastinejad, Fraydoon

    2003-01-01

    .... The research goals associated with this study are to characterize the structural and functional aspects of the AR in order to uncover the potential of its domains, and in particular the DNA-binding...

  10. Theoretical Study of Molecular Determinants Involved in Signal Binding to the TraR Protein of Agrobacterium tumefaciens

    Directory of Open Access Journals (Sweden)

    N. Kumar

    2005-10-01

    Full Text Available N-acylated homoserine lactone (AHL mediated cell-cell communication in bacteria is dependent on the recognition of the cognate signal by its receptor. This interaction allows the receptor-ligand complex to act as a transcriptional activator, controlling the expression of a range of bacterial phenotypes, including virulence factor expression and biofilm formation. One approach to determine the key features of signal- binding is to model the intermolecular interactions between the receptor and ligand using computational-based modeling software (LigandFit. In this communication, we have modeled the crystal structure of the AHL receptor protein TraR and its AHL signal N-(3- oxooctanoyl-homoserine lactone from Agrobacterium tumefaciens and compared it to the previously reported antagonist behaviour of a number of AHL analogues, in an attempt to determine structural constraints for ligand binding. We conclude that (i a common conformation of the AHL in the hydrophobic and hydrophilic region exists for ligand-binding, (ii a tail chain length threshold of 8 carbons is most favourable for ligand-binding affinity, (iii the positive correlation in the docking studies could be used a virtual screening tool.

  11. NMR studies of DNA oligomers and their interactions with minor groove binding ligands

    Energy Technology Data Exchange (ETDEWEB)

    Fagan, Patricia A. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1996-05-01

    The cationic peptide ligands distamycin and netropsin bind noncovalently to the minor groove of DNA. The binding site, orientation, stoichiometry, and qualitative affinity of distamycin binding to several short DNA oligomers were investigated by NMR spectroscopy. The oligomers studied contain A,T-rich or I,C-rich binding sites, where I = 2-desaminodeoxyguanosine. I•C base pairs are functional analogs of A•T base pairs in the minor groove. The different behaviors exhibited by distamycin and netropsin binding to various DNA sequences suggested that these ligands are sensitive probes of DNA structure. For sites of five or more base pairs, distamycin can form 1:1 or 2:1 ligand:DNA complexes. Cooperativity in distamycin binding is low in sites such as AAAAA which has narrow minor grooves, and is higher in sites with wider minor grooves such as ATATAT. The distamycin binding and base pair opening lifetimes of I,C-containing DNA oligomers suggest that the I,C minor groove is structurally different from the A,T minor groove. Molecules which direct chemistry to a specific DNA sequence could be used as antiviral compounds, diagnostic probes, or molecular biology tools. The author studied two ligands in which reactive groups were tethered to a distamycin to increase the sequence specificity of the reactive agent.

  12. Evaluation of a rapid dipstick (Crystal VC for the diagnosis of cholera in Zanzibar and a comparison with previous studies.

    Directory of Open Access Journals (Sweden)

    Benedikt Ley

    Full Text Available The gold standard for the diagnosis of cholera is stool culture, but this requires laboratory facilities and takes at least 24 hours. A rapid diagnostic test (RDT that can be used by minimally trained staff at treatment centers could potentially improve the reporting and management of cholera outbreaks.We evaluated the Crystal VC™ RDT under field conditions in Zanzibar in 2009. Patients presenting to treatment centers with watery diarrhea provided a stool sample for rapid diagnostic testing. Results were compared to stool culture performed in a reference laboratory. We assessed the overall performance of the RDT and evaluated whether previous intake of antibiotics, intravenous fluids, location of testing, and skill level of the technician affected the RDT results.We included stool samples from 624 patients. Compared to culture, the overall sensitivity of the RDT was 93.1% (95%CI: 88.7 to 96.2%, specificity was 49.2% (95%CI: 44.3 to 54.1%, the positive predictive value was 47.0% (95%CI: 42.1 to 52.0% and the negative predictive value was 93.6% (95%CI: 89.6 to 96.5%. The overall false positivity rate was 50.8% (213/419; fieldworkers frequently misread very faint test lines as positive.The observed sensitivity of the Crystal VC RDT evaluated was similar compared to earlier versions, while specificity was poorer. The current version of the RDT could potentially be used as a screening tool in the field. Because of the high proportion of false positive results when field workers test stool specimens, positive results will need to be confirmed with stool culture.

  13. An allosteric binding site at the human serotonin transporter mediates the inhibition of escitalopram by R-citalopram: kinetic binding studies with the ALI/VFL-SI/TT mutant.

    Science.gov (United States)

    Zhong, Huailing; Hansen, Kasper B; Boyle, Noel J; Han, Kiho; Muske, Galina; Huang, Xinyan; Egebjerg, Jan; Sánchez, Connie

    2009-10-25

    The human serotonin transporter (hSERT) has primary and allosteric binding sites for escitalopram and R-citalopram. Previous studies have established that the interaction of these two compounds at a low affinity allosteric binding site of hSERT can affect the dissociation of [(3)H]escitalopram from hSERT. The allosteric binding site involves a series of residues in the 10th, 11th, and 12th trans-membrane domains of hSERT. The low affinity allosteric activities of escitalopram and R-citalopram are essentially eliminated in a mutant hSERT with changes in some of these residues, namely A505V, L506F, I507L, S574T, I575T, as measured in dissociation binding studies. We confirm that in association binding experiments, R-citalopram at clinically relevant concentrations reduces the association rate of [(3)H]escitalopram as a ligand to wild type hSERT. We demonstrate that the ability of R-citalopram to reduce the association rate of escitalopram is also abolished in the mutant hSERT (A505V, L506F, I507L, S574T, I575T), along with the expected disruption the low affinity allosteric function on dissociation binding. This suggests that the allosteric binding site mediates both the low affinity and higher affinity interactions between R-citalopram, escitalopram, and hSERT. Our data add an additional structural basis for the different efficacies of escitalopram compared to racemic citalopram reported in animal studies and clinical trials, and substantiate the hypothesis that hSERT has complex allosteric mechanisms underlying the unexplained in vivo activities of its inhibitors.

  14. Multispectroscopic and calorimetric studies on the binding of the food colorant tartrazine with human hemoglobin.

    Science.gov (United States)

    Basu, Anirban; Suresh Kumar, Gopinatha

    2016-11-15

    Interaction of the food colorant tartrazine with human hemoglobin was studied using multispectroscopic and microcalorimetric techniques to gain insights into the binding mechanism and thereby the toxicity aspects. Hemoglobin spectrum showed hypochromic changes in the presence of tartrazine. Quenching of the fluorescence of hemoglobin occurred and the quenching mechanism was through a static mode as revealed from temperature dependent and time-resolved fluorescence studies. According to the FRET theory the distance between β-Trp37 of hemoglobin and bound tartrazine was evaluated to be 3.44nm. Synchronous fluorescence studies showed that tartrazine binding led to alteration of the microenvironment around the tryptophans more in comparison to tyrosines. 3D fluorescence and FTIR data provided evidence for conformational changes in the protein on binding. Circular dichroism studies revealed that the binding led to significant loss in the helicity of hemoglobin. The esterase activity assay further complemented the circular dichroism data. Microcalorimetric study using isothermal titration calorimetry revealed the binding to be exothermic and driven largely by positive entropic contribution. Dissection of the Gibbs energy change proposed the protein-dye complexation to be dominated by non-polyelectrolytic forces. Negative heat capacity change also corroborated the involvement of hydrophobic forces in the binding process. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Studies of the Binding of Modest Modulators of the Human Enzyme, Sirtuin 6, by STD NMR.

    Science.gov (United States)

    Bolívar, Beatriz E; Welch, John T

    2017-05-18

    Pyrazinamide (PZA), an essential constituent of short-course tuberculosis chemotherapy, binds weakly but selectively to Sirtuin 6 (SIRT6). Despite the structural similarities between nicotinamide (NAM), PZA, and pyrazinoic acid (POA), these inhibitors modulate SIRT6 by different mechanisms and through different binding sites, as suggested by saturation transfer difference (STD) NMR. Available experimental evidence, such as that derived from crystal structures and kinetic experiments, has been of only limited utility in elucidation of the mechanistic details of sirtuin inhibition by NAM or other inhibitors. For instance, crystallographic structural analysis of sirtuin binding sites does not help us understand important differences in binding affinities among sirtuins or capture details of such dynamic process. Hence, STD NMR was utilized throughout this study. Our results not only agreed with the binding kinetics experiments but also gave a qualitative insight into the binding process. The data presented herein suggested some details about the geometry of the binding epitopes of the ligands in solution with the apo- and holoenzyme. Recognition that SIRT6 is affected selectively by PZA, an established clinical agent, suggests that the rational development of more potent and selective NAM surrogates might be possible. These derivatives might be accessible by employing the malleability of this scaffold to assist in the identification by STD NMR of the motifs that interact with the apo- and holoenzymes in solution. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Dopamine receptors in the guinea-pig heart. A binding study

    International Nuclear Information System (INIS)

    Sandrini, M.; Benelli, A.; Baraldi, M.

    1984-01-01

    The binding of dopaminergic agonists and antagonists to guinea-pig myocardial membrane preparations was studied using 3 H-dopamine and 3 H-spiperone as radioligand. 3 H-Dopamine bound specifically to heart membranes while 3 H-spiperone did not. A Scatchard analysis of 3 H-dopamine binding showed a curvilinear plot indicating the presence of two dopamine receptor populations that we have termed high- (K/sub d/ = 1.2 nM, B/sub mx/ = 52.9 fmol/mg prot.) and low- (K/sub d/ = 11.8 nM, B/sub mx/ = 267.3 fmol/gm prot.) affinity binding sites, respectively. The charactization of the high-affinity component of 3 H-dopamine binding indicated that the binding is rapid, saturable, stereospecific, pH- and temperature-dependent, and displaced by dopaminergic agonists and antagonists known to act similarly in vivo. The finding that pretreatment with dibenamine (which has been described as an α-adrenoceptor irreversible blocker) did not affect the binding of dopamine to cardiac membrane preparations suggests that α-adrenoceptors and dopamine receptors have separate recognition sites in the heart. It is concluded that 3 H-dopamine binds to specific dopamine receptors in the heart of guinea-pigs

  17. PREVIOUS SECOND TRIMESTER ABORTION

    African Journals Online (AJOL)

    PNLC

    PREVIOUS SECOND TRIMESTER ABORTION: A risk factor for third trimester uterine rupture in three ... for accurate diagnosis of uterine rupture. KEY WORDS: Induced second trimester abortion - Previous uterine surgery - Uterine rupture. ..... scarred uterus during second trimester misoprostol- induced labour for a missed ...

  18. Studies in iodine metabolism: 33 year summary, 1948-1979 (as previously submitted) with appendix, 1979-1982

    International Nuclear Information System (INIS)

    Middlesworth, L.V.

    1982-01-01

    The results of research into iodine metabolism from 1948 to 1982 are summarized. Study areas included the monitoring of iodine 131 from fallout in the thyroid glands of cattle and humans, the biological functions and metabolism of thyroid hormones, and methods to reduce the retention of radioiodine in the thyroid

  19. Fever-Induced Brugada Syndrome Is More Common Than Previously Suspected: A Cross-Sectional Study from an Endemic Area.

    Science.gov (United States)

    Rattanawong, Pattara; Vutthikraivit, Wasawat; Charoensri, Attawit; Jongraksak, Tanawat; Prombandankul, Awapa; Kanjanahattakij, Napatt; Rungaramsin, Sakda; Wisaratapong, Treechada; Ngarmukos, Tachapong

    2016-03-01

    Brugada syndrome (BrS) is defined as presenting of type-1 Brugada pattern (BrP). BrS can also be induced by fever. This study demonstrated a highest prevalence of fever-induced BrS ever reported. During May 2014, febrile (oral temperature ≥ 38 °C) and nonfebrile patients underwent standard and high leads (V1 and V2 at 2nd intercostal space) electrocardiogram. Risk factor and cardiac symptoms were recorded. Patients with a persistent of type-1 BrP after fever had subsided were excluded. The prevalence of BrS, type-2 BrP and early repolarization pattern (ERP) were demonstrated. A total of 401 patients, 152 febrile, and 249 nonfebrile, were evaluated. BrS was identified in six febrile patients (five males and one female) and two males in nonfebrile patients. The study demonstrated higher prevalence of BrS in febrile group compared to nonfebrile group (4.0% vs 0.8%, respectively, P = 0.037). Among fever-induced BrS patients, three patients (50.0%) experienced cardiac symptoms before and at the time of presentation and two patients (33.3%) had history of first-degree relative sudden death. No ventricular arrhythmia was observed. All of type-1 BrP disappeared after fever had subsided. We found no difference in prevalence of type-2 BrP in febrile and nonfebrile group (2.0% vs 2.8%, respectively, P > 0.05) as well as ERP (3.3% vs 6.4%, respectively, P > 0.05). Our study showed a highest prevalence of fever induced BrS ever reported. A larger study of prevalence, risk stratification, genetic test and management of fever-induced BrS should be done, especially in an endemic area. © 2015, Wiley Periodicals, Inc.

  20. Venlafaxine extended release versus conventional antidepressants in the remission of depressive disorders after previous antidepressant failure: ARGOS study.

    Science.gov (United States)

    Baldomero, E Baca; Ubago, J Giner; Cercós, C Leal; Ruiloba, J Vallejo; Calvo, C García; López, R Prieto

    2005-01-01

    Serotonin-norepinephrine reuptake inhibitors (SNRIs) may be used as an alternative treatment for depressed patients who do not tolerate or respond adequately to treatment with a conventional antidepressant. This randomized, open-label, multicenter study compared the effectiveness of the SNRI venlafaxine extended release (VXR) with that of conventional antidepressants (CA) in patients who were referred to an outpatient psychiatric specialty care setting for treatment after failure to tolerate or respond to at least 4 weeks of treatment with a CA in a primary care setting. Patients with a Hamilton Depression Rating Scale (HAM-D17) score > or =17 were randomly assigned to treatment with an alternative CA or VXR. Remission was defined as a score < or =7 on the HAM-D17. Efficacy analyses were carried out on 3,097 patients from the intent-to-treat (ITT) population (1,632 VXR; 1,465 CA). The antidepressants prescribed most frequently in the CA group were paroxetine (21.3%), citalopram (20.1%), sertraline (19.1%), fluoxetine (17.0%), and mirtazapine (7.9%). After 24 weeks of treatment, the VXR group demonstrated a significantly higher remission rate than did the CA group (59.3% VXR; 51.5% CA; P<.0001; odds ratio: 1.37; 95% CI: 1.19-1.58; P<.01). Despite the limitations of the open design, the results of this study suggest that venlafaxine extended release may be more effective than the conventional antidepressants used in this study when treating depressed patients who do not tolerate or respond adequately to treatment with a conventional antidepressant.

  1. CHRONOVAC VOYAGEUR: A study of the immune response to yellow fever vaccine among infants previously immunized against measles.

    Science.gov (United States)

    Goujon, Catherine; Gougeon, Marie-Lise; Tondeur, Laura; Poirier, Béatrice; Seffer, Valérie; Desprès, Philippe; Consigny, Paul-Henri; Vray, Muriel

    2017-10-27

    For administration of multiple live attenuated vaccines, the Advisory Committee on Immunization Practices recommends either simultaneous immunization or period of at least 28days between vaccines, due to a possible reduction in the immune response to either vaccine. The main objective of this study was to compare the immune response to measles (alone or combined with mumps and rubella) and yellow fever vaccines among infants aged 6-24months living in a yellow fever non-endemic country who had receivedmeasles and yellow fever vaccines before travelling to a yellow fever endemic area. A retrospective, multicenter case-control study was carried out in 7 travel clinics in the Paris area from February 1st 2011 to march 31, 2015. Cases were defined as infants immunized with the yellow fever vaccine and with the measles vaccine, either alone or in combination with mumps and rubella vaccine, with a period of 1-27days between each immunization. For each case, two controls were matched based on sex and age: a first control group (control 1) was defined as infants having received the measles vaccine and the yellow fever vaccine simultaneously; a second control group (control 2) was defined as infants who had a period of more than 27days between receiving the measles vaccine and yellow fever vaccine. The primary endpoint of the study was the percentage of infants with protective immunity against yellow fever, measured by the titer of neutralizing antibodies in a venous blood sample. One hundred and thirty-one infants were included in the study (62 cases, 50 infants in control 1 and 19 infants in control 2). Of these, 127 (96%) were shown to have a protective titer of yellow fever antibodies. All 4 infants without a protective titer of yellow fever antibodies were part of control group 1. The measles vaccine, alone or combined with mumps and rubella vaccines, appears to have no influence on humoral immune response to the yellow fever vaccine when administered between 1 and 27

  2. Self-shielding effects in burnup of Gd used as burnable absorber. Previous studies on its experimental verification

    International Nuclear Information System (INIS)

    Abbate, Maximo J.; Sbaffoni, Maria M.

    2003-01-01

    Continuing with the domestic 'Burnable Absorbers Research Plan' studies were done to estimate self-shielding effects during Gd 2 O 3 burnup as burnable absorber included in fuel pins of a CAREM geometry. In this way, its burnup was calculated without and with self-shielding. For the second case, were obtained values depending on internal pin radius and the effective one for the homogenized pin. For Gd 157, the burnup corresponding to the first case resulted 52.6 % and of 1.23 % for the effective one. That shows the magnitude of the effects under study. Considering that is necessary to perform one experimental verification, also are presented calculational results for the case to irradiate a pellet containing UO 2 (natural) and 8 wt % of Gd 2 O 3 , as a function of cooling time, that include: measurable isotopes concentrations, expected activities, and photon spectra for conditions able to be compared with bidimensional calculations with self-shielding. The irradiation time was supposed 30 dpp using RA-3 reactor at 10 MW. (author)

  3. Grain boundaries in bcc-Fe: a density-functional theory and tight-binding study

    Science.gov (United States)

    Wang, Jingliang; Madsen, Georg K. H.; Drautz, Ralf

    2018-02-01

    Grain boundaries (GBs) have a significant influence on material properties. In the present paper, we calculate the energies of eleven low-Σ ({{Σ }}≤slant 13) symmetrical tilt GBs and two twist GBs in ferromagnetic bcc iron using first-principles density functional theory (DFT) calculations. The results demonstrate the importance of a sufficient sampling of initial rigid body translations in all three directions. We show that the relative GB energies can be explained by the miscoordination of atoms at the GB region. While the main features of the studied GB structures were captured by previous empirical interatomic potential calculations, it is shown that the absolute values of GB energies calculated were substantially underestimated. Based on DFT-calculated GB structures and energies, we construct a new d-band orthogonal tight-binding (TB) model for bcc iron. The TB model is validated by its predictive power on all the studied GBs. We apply the TB model to block boundaries in lath martensite and demonstrate that the experimentally observed GB character distribution can be explained from the viewpoint of interface energy.

  4. Experimental and theoretical study on the binding of 2-mercaptothiazoline to bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Yue, E-mail: tengyue@jiangnan.edu.cn; Wang, Xiang; Zou, Luyi; Huang, Ming; Du, Xianzheng

    2015-05-15

    2-Mercaptothiazoline (MTZ) is widely utilized as a brightening and stabilization agent, corrosion inhibitor and antifungal reagent. The residue of MTZ in the environment is potentially hazardous to human health. In this study, the binding mode of MTZ with bovine serum albumin (BSA) was investigated using spectroscopic and molecular docking methods under physiological conditions. MTZ could spontaneously bind with BSA through hydrogen bond and van der Waals interactions with one binding site. The site marker displacement experiments and the molecular docking revealed that MTZ bound into site II (subdomain IIIA) of BSA, which further resulted in some backbone structures and microenvironmental changes of BSA. This work is helpful for understanding the transportation, distribution and toxicity effects of MTZ in blood. - Highlights: • The mechanism was explored by multiple spectroscopic and molecular docking methods. • MTZ can spontaneously bind with BSA at subdomain IIIA (site II). • MTZ can lead to some conformational changes of BSA.

  5. A genome-wide association study confirms previously reported loci for type 2 diabetes in Han Chinese.

    Directory of Open Access Journals (Sweden)

    Bin Cui

    Full Text Available BACKGROUND: Genome-wide association study (GWAS has identified more than 30 loci associated with type 2 diabetes (T2D in Caucasians. However, genomic understanding of T2D in Asians, especially Han Chinese, is still limited. METHODS AND PRINCIPAL FINDINGS: A two-stage GWAS was performed in Han Chinese from Mainland China. The discovery stage included 793 T2D cases and 806 healthy controls genotyped using Illumina Human 660- and 610-Quad BeadChips; and the replication stage included two independent case-control populations (a total of 4445 T2D cases and 4458 controls genotyped using TaqMan assay. We validated the associations of KCNQ1 (rs163182, p = 2.085×10(-17, OR 1.28 and C2CD4A/B (rs1370176, p = 3.677×10(-4, OR 1.124; rs1436953, p = 7.753×10(-6, OR 1.141; rs7172432, p = 4.001×10(-5, OR 1.134 in Han Chinese. CONCLUSIONS AND SIGNIFICANCE: Our study represents the first GWAS of T2D with both discovery and replication sample sets recruited from Han Chinese men and women residing in Mainland China. We confirmed the associations of KCNQ1 and C2CD4A/B with T2D, with the latter for the first time being examined in Han Chinese. Arguably, eight more independent loci were replicated in our GWAS.

  6. Photocatalytic oxidation dynamics of acetone on TiO2: tight-binding quantum chemical molecular dynamics study

    International Nuclear Information System (INIS)

    Lv Chen; Wang Xiaojing; Agalya, Govindasamy; Koyama, Michihisa; Kubo, Momoji; Miyamoto, Akira

    2005-01-01

    The clarification of the excited states dynamics on TiO 2 surface is important subject for the design of the highly active photocatalysts. In the present study, we applied our novel tight-binding quantum chemical molecular dynamics method to the investigation on the photocatalytic oxidation dynamics of acetone by photogenerated OH radicals on the hydrated anatase TiO 2 surface. The elucidated photocatalytic reaction mechanism strongly supports the previous experimental proposal and finally the effectiveness of our new approach for the clarification of the photocatalytic reaction dynamics employing the large simulation model was confirmed

  7. Binding Studies of Andrographolide with Human serum albumin: Molecular Docking, Chromatographic and Spectroscopic studies.

    Science.gov (United States)

    Godugu, Deepika; Rupula, Karuna; Beedu, Sashidhar Rao

    2018-02-11

    Andrographolide, sourced from Andrographis paniculata, is an established therapeutic agent with variety of pharmacological properties in treatment of various diseases. The present study is designed to evaluate the interaction and binding affinity of andrographolide with HSA by docking and spectral studies. The docking study for screening the interaction of andrographolide with HSA protein was carried out using Auto Dock Vina software and the binding score of andrographolide was -8.7 kcal mol-1 and formed one hydrogen bond with Arg 218 residue of HSA in sub-domains IIA region. The formation of HSA-andrographolide complex was characterized by spectroscopic methods - UV absorption, HPLC, CD and FTIR analysis. The UV spectral analysis revealed a decrease in the absorption peak of HSA due to its interaction with andrographolide. A new peak was observed at retention time 7.45 min by HPLC analysis and the Bmax was found to be 7.5 ± 0.4 mg protein with a Kd value of 1.89 mM, indicating interaction of andrographolide with HSA. The CD spectra results suggested, a marginal decrease in the negative ellipticity without any significant shift in peak, indicating the stabilization of the HSA-andrographolide complex. The FTIR analysis further confirmed, a shift of amide I groups from 1646 to 1637 cm-1 and a peak at 1016 cm-1 in andrographolide, was observed in the complex, indicating the interaction. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Comparative study of a novel application of automated HR HPV assay and stability in a previously untested Preservative media.

    Science.gov (United States)

    Morel, Mike E; McBride, Simon E; Gomez, Maria P

    2017-12-01

    The suitability and stability of cervical cells in Novaprep media (NHQ) for certain HPV assays is unknown. We evaluated the accuracy of an automated HPV assay (Abbott RealTime HR HPV) for cervical cells prepared in NHQ and NHQ with a pre-treatment to mimic a worst case clinical use, compared to the assay manufacturers media; repeatability and reproducibility of HPV results and the stability of detectable HPV in NHQ over time compared to CE marked liquid based cytology preservatives. Cell lines were used to simulate patient samples. Cells stored in NHQ produced accurate, repeatable and reproducible results. Stability in NHQ was comparable to the best performing LBC, with at least 7 months' stability at 18-25°C, 2-8°C, -20°C and -80°C; and at least 3 months' stability at 40°C. Similar results were obtained for pre-treated NHQ except only 3.5 months' stability at 18-25°C. Cell line samples in all media and concentrations tested were detected appropriately by the assay. Based on this first stage validation analytical study, cervical cells stored in NHQ are suitable for the Realtime HPV assay. There should be no reservations for inclusion of NHQ in any further validation and clinical performance evaluation of this assay. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  9. DNA binding affinity of a macrocyclic copper(II) complex: Spectroscopic and molecular docking studies.

    Science.gov (United States)

    Shahabadi, Nahid; Hakimi, Mohammad; Morovati, Teimoor; Fatahi, Navid

    2017-08-03

    The interaction of a novel macrocyclic copper(II) complex, ([CuL(ClO 4 ) 2 ] that L is 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1 6,10 ]eicosane) with calf thymus DNA (ct-DNA) was investigated by various physicochemical techniques and molecular docking at simulated physiological conditions (pH = 7.4). The absorption spectra of the Cu(II) complex with ct-DNA showed a marked hyperchroism with 10 nm blue shift. The intrinsic binding constant (K b ) was determined as 1.25 × 10 4 M -1 , which is more in keeping with the groove binding with DNA. Furthermore, competitive fluorimetric studies with Hoechst33258 have shown that Cu(II) complex exhibits the ability to displace the ct-DNA-bound Hoechst33258 indicating that it binds to ct-DNA in strong competition with Hoechst33258 for the groove binding. Also, no change in the relative viscosity of ct-DNA and fluorescence intensity of ct-DNA-MB complex in the present of Cu(II) complex is another evidence to groove binding. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the binding reaction. The experimental results were in agreement with the results obtained via molecular docking study.

  10. Comparison of [11C]cocaine binding at tracer and pharmacological doses of baboon brain: A PET study

    Energy Technology Data Exchange (ETDEWEB)

    Volkow, N.D.; Fowler, J.S.; Logan, J. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1994-05-01

    In vitro studies have shown that cocaine (C) binds to both high and low affinity sites on the dopamine transporter (DAT). We have previously characterized the binding of tracer doses of [{sup 11}C]cocaine (C*)to a high affinity site on the DAT. To assess if in vivo C also binds to low affinity sites we used PET to compare binding of tracer doses (17.8{plus_minus}12.2 {mu}g C) of C* to pharmacological doses (8 mg of C coadministered with C*). Sixteen paired studies were done to assess test/retest variability, specific versus non specific binding and to characterize binding profile. Dynamic scans were started immediately after injection of C* (5-8 mCi) for 50 min on the CTI-931 (6 x 6 x 6.5 mm FWHM). Time activity curves for tissue concentration and for unchanged tracer in plasma were used to calculate the transport constant between plasma and tissue (K1) and to obtain the distribution volume (DV). The ratio of the DV in striatum (ST) to that in cerebellum (CB) (which corresponds to Bmax/Kd-1) was used as model parameter. Peak brain uptake of C* was significantly higher for tracer than for pharmacological doses (0.041 versus 0.033 % dose/cc), as were the values for K1 (1.07{plus_minus}0.21 versus 0.68{plus_minus}0.26 (t=3.0 p<0.01)). Repeated measures were reproducible for tracer ({plus_minus}2%) and pharmacological doses of C* ({plus_minus}4%). Tracer dose C* showed highest binding and slowest clearance in ST which was reduced by C (0.5-2.0 mg/kg iv, -25 to -30%) and by drugs that inhibit DAT (2mg/kg nomifensine - 21%, 0.5 mg/kg methylphenidate -12%) and was increased by serotonin transporter inhibitors (5HT-Ti) (2 mg/kg citalopram +11%, 0.5 mg/kg fluoxetine +6%) and not changed by NE transporter inhibitors (0.5 mg/kg desipramine or 2 mg/kg tomoxetine). The increase with (5HT-Ti) may reflect neurotransmitter interactions or changes in bioavailability. At pharmacological doses C* showed homogeneous distribution and was not changed by C nor by any of the above drugs.

  11. Knowledge of stroke risk factors among primary care patients with previous stroke or TIA: a questionnaire study

    Directory of Open Access Journals (Sweden)

    Strender Lars-Erik

    2010-06-01

    Full Text Available Abstract Background Survivers of stroke or transient ischaemic attacks (TIA are at risk of new vascular events. Our objective was to study primary health care patients with stroke/TIA regarding their knowledge about risk factors for having a new event of stroke/TIA, possible associations between patient characteristics and patients' knowledge about risk factors, and patients' knowledge about their preventive treatment for stroke/TIA. Methods A questionnaire was distributed to 240 patients with stroke/TIA diagnoses, and 182 patients (76% responded. We asked 13 questions about diseases/conditions and lifestyle factors known to be risk factors and four questions regarding other diseases/conditions ("distractors". The patients were also asked whether they considered each disease/condition to be one of their own. Additional questions concerned the patients' social and functional status and their drug use. The t-test was used for continuous variables, chi-square test for categorical variables, and a regression model with variables influencing patient knowledge was created. Results Hypertension, hyperlipidemia and smoking were identified as risk factors by nearly 90% of patients, and atrial fibrillation and diabetes by less than 50%. Few patients considered the distractors as stroke/TIA risk factors (3-6%. Patients with a family history of cardiovascular disease, and patients diagnosed with carotid stenosis, atrial fibrillation or diabetes, knew these were stroke/TIA risk factors to a greater extent than patients without these conditions. Atrial fibrillation or a family history of cardiovascular disease was associated with better knowledge about risk factors, and higher age, cerebral haemorrhage and living alone with poorer knowledge. Only 56% of those taking anticoagulant drugs considered this as intended for prevention, while 48% of those taking platelet aggregation inhibitors thought this was for prevention. Conclusions Knowledge about hypertension

  12. Synthesis and structure elucidation of a copper(II) Schiff-base complex: in vitro DNA binding, pBR322 plasmid cleavage and HSA binding studies.

    Science.gov (United States)

    Tabassum, Sartaj; Ahmad, Musheer; Afzal, Mohd; Zaki, Mehvash; Bharadwaj, Parimal K

    2014-11-01

    New copper(II) complex with Schiff base ligand 4-[(2-Hydroxy-3-methoxy-benzylidene)-amino]-benzoic acid (H₂L) was synthesized and characterized by spectroscopic and analytical and single crystal X-ray diffraction studies which revealed that the complex 1 exist in a distorted octahedral environment. In vitro CT-DNA binding studies were performed by employing different biophysical technique which indicated that the 1 strongly binds to DNA in comparison to ligand via electrostatic binding mode. Complex 1 cleaves pBR322 DNA via hydrolytic pathway and recognizes minor groove of DNA double helix. The HSA binding results showed that ligand and complex 1 has ability to quench the fluorescence emission intensity of Trp 214 residue available in the subdomain IIA of HSA. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Spectroscopic study of binding of chlorogenic acid with the surface of ZnO nanoparticles

    Science.gov (United States)

    Belay, Abebe; Kim, Hyung Kook; Hwang, Yoon-Hwae

    2017-09-01

    Understanding the interaction properties of biological materials with ZnO NPs is fundamental interest in the field of biotechnological applications as well as in the formation of optoelectronic devices. In this research, the binding of ZnO NPs and chlorogenic acid (CGA) were investigated using fluorescence quenching, UV-Vis absorption spectroscopy, Fourier transform infrared (FTIR), Raman spectroscopy, scanning electron microscopy (TEM), and dynamic light scattering (DLS) techniques. The study results indicated the fluorescence quenching between ZnO NPs and CGA rationalized in terms of static quenching mechanism or the formation of nonfluorescent CGA-ZnO. From fluorescence quenching spectral analysis the binding constant ( K a ), number of binding sites ( n), and thermodynamic properties, were determined. The quenching constants ( K sv) and binding constant ( K a ), decrease with increasing the temperature and their binding sites n are 2. The thermodynamic parameters determined using Van't Hoff equation indicated binding occurs spontaneously involving the hydrogen bond and van der Walls forces played the major role in the reaction of ZnO NPs with CGA. The Raman, SEM, DLS, and Zeta potential measurements were also indicated the differences in the structure, morphology and sizes of CGA, ZnO NPs, and their corresponding CGA-ZnO due to adsorption of CGA on the surface of ZnO NPs

  14. A comparative study of procedures for binding of aflatoxin M1 to Lactobacillus rhamnosus GG.

    Science.gov (United States)

    Assaf, Jean Claude; Atoui, Ali; Khoury, André El; Chokr, Ali; Louka, Nicolas

    Several strains of lactic acid bacteria (LAB), frequently used in food fermentation and preservation, have been reported to bind different types of toxins in liquid media. This study was carried out to investigate the effect of different concentrations of Lactobacillus rhamnosus GG (ATCC 53103) to bind aflatoxin M1 (AFM1) in liquid media. AFM1 binding was tested following repetitive washes or filtration procedures in combination with additional treatments such as heating, pipetting, and centrifugation. The mixture of L. rhamnosus GG and AFM1 was incubated for 18h at 37°C and the binding efficiency was determined by quantifying the unbound AFM1 using HPLC. The stability of the complexes viable bacteria-AFM1 and heat treated bacteria-AFM1 was tested. Depending on the bacterial concentration and procedure used, the percentages of bound AFM1 by L. rhamnosus GG varied from as low as undetectable to as high as 63%. The highest reduction in the level of unbound AFM1 was recorded for the five washes procedure that involved heating and pipetting. Results also showed that binding was partially reversible and AFM1 was released after repeated washes. These findings highlight the effect of different treatments on the binding of AFM1 to L. rhamnosus GG in liquid matrix. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Interference of anaesthetics with radioligand binding in neuroreceptor studies

    Energy Technology Data Exchange (ETDEWEB)

    Elfving, Betina; Knudsen, Gitte Moos [Neurobiology Research Unit N9201, University hospital Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen (Denmark); Bjoernholm, Berith [Department of Computational Chemistry, H. Lundbeck A/S, Copenhagen-Valby (Denmark)

    2003-06-01

    Evaluations of new emission tomography ligands are usually carried out in animals. In order to keep the animals in a restricted position during the scan session, anaesthesia is almost inevitable. In ex vivo rat studies we investigated the interference of ketamine/xylazine, zoletile mixture, isoflurane and halothane with the serotonin re-uptake site, the serotonin{sub 2A} receptor and the dopamine re-uptake site by use of [{sup 3}H]-(S)-citalopram, [{sup 18}F]altanserin and [{sup 125}I]PE2I, respectively. Ketamine/xylazine decreased the target-to-background ratio (mean {+-} SD) of [{sup 3}H]-(S)-citalopram from 1.5{+-}0.19 to 0.81{+-}0.19 (P<0.05), whereas isoflurane and halothane increased the ratio from 1.5{+-}0.19 to 1.9{+-}0.24 and 2.1{+-}0.13 (P<0.05), respectively. Only with the zoletile mixture did the ratio remain unaltered. None of the tested anaesthetics affected the target-to-background ratio of [{sup 18}F]altanserin. The [{sup 125}I]PE2I target-to-background ratio decreased with both ketamine/xylazine (from 12.4{+-}0.81 to 10.1{+-}1.4, P<0.05) and isoflurane (from 12.4{+-}0.81 to 9.5{+-}1.1, P<0.05) treated rats, whereas treatment with zoletile mixture and halothane left the ratio unaltered. It is concluded that prior to performance of neuroreceptor radioligand studies, the possible interaction between radioligands and anaesthetics should be carefully evaluated. (orig.)

  16. Binding of an anticancer Rutaceae plant flavonoid glycoside with calf thymus DNA: Biophysical and electrochemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, Sandhya; Jaldappagari, Seetharamappa, E-mail: jseetharam@yahoo.com

    2013-10-15

    In the present work, we report the interaction of a bioactive Rutaceae plant flavonoid glycoside, diosmin (DIO) with calf thymus DNA employing ethidium bromide as a fluorescence probe. The mode of binding between DIO and DNA was investigated by UV absorption, fluorescence, 3D-fluorescence, fluorescence polarization, FT-IR, circular dichroism, melting temperature (T{sub m}) measurements and differential pulse voltammogram studies. The results revealed the intercalative mode of binding between DIO and DNA. Further, the values of thermodynamic parameters, ∆H° (−388.32 kJ mol{sup −1}) and ∆S° (−1.22 kJ mol{sup −1} K{sup −1}) indicated that the van der Waals forces and hydrogen bond played a major role in the binding of DIO to DNA. The observed negative ∆G° values revealed the spontaneity of interaction process. The binding of DIO to DNA–EB was found to be stronger in the presence of coexisting substances. -- Highlights: • Mechanism of interaction of diosmin with DNA was studied by spectroscopic methods. • Ethidium bromide was used as a fluorescence probe in the present study. • The van der Waals forces and hydrogen bond played a significant role in the interaction. • Intercalative mode of binding was proposed between DIO and DNA.

  17. Synthesis of schiff bases of pyridine-4-carbaldehyde and their antioxidant and DNA binding studies

    International Nuclear Information System (INIS)

    Shamim, S.; Murtaza, S.; Nazar, M.F.

    2016-01-01

    A series of Schiff bases of pyridine-4-carbaldehyde with 3-aminobenzoic acid, 2-aminobenzoic acid, 4-aminobenzoic acid, 1,3-phenylenediamine, 1,2-phenylenediamine, 2-aminothiophenol, 4-aminoantipyrene, 2-aminophenol and naphthalene-1-amine was synthesized and compounds were characterized by FTIR, NMR and mass spectrometry. The synthesized compounds were evaluated for their antioxidant and DNA binding interaction studies. DPPH scavenging method was used to evaluate the antioxidant activities of synthesized Schiff bases at six gradually increasing concentrations of 0.5-5mg/ml. 2-((pyridin-4-ylmethylidene)amino)phenol came out to be the most efficient antioxidant at a concentration of 4mg/ml with 74% inhibition of free radicals generated by DPPH. The DNA binding interaction of the synthesized Schiff bases was determined using UV-Vis absorption titration method. Both the hypochromic and hyperchromic effects were observed along the series. The values for the binding constant (K) and free energy change (G) were calculated and most of the Schiff bases have high positive K values which indicate the efficient binding of Schiff bases with DNA. Molecular docking studies as carried out using PatchDock molecular algorithm software also indicated the high values for geometrical shape complementarity score suggesting the stabilities of Schiff bases/DNA complex. Docking studies also suggested the minor groove binding of the Schiff bases with DNA. Drug-likeness of the synthesized compounds was also tested in silico and the results are accordingly discussed. (author)

  18. Effective binding of perhalogenated closo-borates to serum albumins revealed by spectroscopic and ITC studies

    Science.gov (United States)

    Kuperman, Marina V.; Losytskyy, Mykhaylo Yu.; Bykov, Alexander Yu.; Yarmoluk, Sergiy M.; Zhizhin, Konstantin Yu.; Kuznetsov, Nikolay T.; Varzatskii, Oleg A.; Gumienna-Kontecka, Elzbieta; Kovalska, Vladyslava B.

    2017-08-01

    The interactions of boron cluster compounds closo-borates with biomolecules are widely studied due to their efficiency as agents for boron neutron capture therapy of cancer. In present work the binding abilities of anionic halogen closo-borates [B10Hal10]2- (Hal = Cl, Br, I) and [B12Hal12]2- (Hal = Cl, I) towards bovine and human serum albumins were investigated by spectroscopic and isothermal titration calorimetry (ITC) methods. The protein fluorescence quenching method and ITC studies confirmed the complex formation. The degree of protein fluorescence quenching increased from chlorine to iodine boron derivatives that is attributed to external heavy atom effect. The ITC data point on the existence in the protein structure of two types of binding sites: with higher and lower affinity to closo-borates. Albumin-closo-borate complex binding ratio, n (4-5 anions per protein molecule) is higher than for the parent hydrogen closo-borates (2 anions per protein molecule). Binding constants estimated by fluorescent and ITC methods indicate higher affinity of halogen closo-borates to albumins (K in the range of 104-106 M-1) comparing to that of the hydrogen closo-borate (K about 103 M-1). Due to their high affinity and high binding ratio to albumins halogen closo-borates are proposed for further studies as agents for boron neutron capture therapy.

  19. Studying protein binding to conjugated gold nanospheres; application of Mie light scattering to reaction kinetics.

    Science.gov (United States)

    Lunt, E A M; Pitter, M C; Somekh, M G; O'Shea, P

    2008-09-01

    The study of protein interactions is an area of much interest, particularly towards obtaining more detailed information about biological processes. Current methods involve the use of complicated, specialised techniques which are beyond the scope of most laboratories. Here, we show how information about the binding of proteins to conjugated gold nanospheres can be obtained using straightforward experimental techniques. A Perkin Elmer LS 55 luminescence spectrometer was used to observe the changes in light scattering caused by the binding of complementary proteins to conjugated nanoparticles, measured by the intensity change over time. Mie theory simulations have been used to predict the expected observations and to quantify the changes in intensity as a function of surface coverage. Further kinetic studies have been carried out at 530 nm to obtain more detailed information about the processes involved in the binding reaction. Thus, we have demonstrated that the interaction of proteins can be studied using a straightforward method which provides information about surface coverage and reaction kinetics.

  20. Synthesis, crystal structure, DNA binding and molecular docking studies of zinc(II) carboxylates

    Science.gov (United States)

    Muhammad, Niaz; Ikram, Muhammad; Wadood, Abdul; Rehman, Sadia; Shujah, Shaukat; Erum; Ghufran, Mehreen; Rahim, Shahnaz; Shah, Muzamil; Schulzke, Carola

    2018-02-01

    New zinc(II) carboxylate complexes [Zn(3-F-C6H4CH2COO)2]n (1), [Zn3(3-F-C6H4CH2COO)6(Phen)2] (2) and [Zn3(3-F-C6H4CH2COO)6(bipy)2] (3) were synthesized and characterized by atomic absorption, single crystal structural analysis and IR studies. Complex 1 crystallizes as a coordination polymer constituting a web of μ - η1,η1 carboxylate bridged tetrahedral zinc centers. Complexes 2 and 3 comprise trinuclear zinc centers with two terminal fivefold coordinated slightly distorted square-pyramidal and central sixfold coordinated octahedral zinc centers. The complexes were also assessed for their DNA binding ability by UV/- Vis spectroscopy and their behavior rationalized theoretically by molecular docking studies. A DNA binding study has shown groove binding interactions with the complexes.

  1. Insights into substrate binding to the oxygen-evolving complex of photosystem II from ammonia inhibition studies.

    Science.gov (United States)

    Vinyard, David J; Brudvig, Gary W

    2015-01-20

    Water oxidation in Photosystem II occurs at the oxygen-evolving complex (OEC), which cycles through distinct intermediates, S0-S4. The inhibitor ammonia selectively binds to the S2 state at an unresolved site that is not competitive with substrate water. By monitoring the yields of flash-induced oxygen production, we show that ammonia decreases the net efficiency of OEC turnover and slows the decay kinetics of S2 to S1. The temperature dependence of biphasic S2 decay kinetics provides activation energies that do not vary in control and ammonia conditions. We interpret our data in the broader context of previous studies by introducing a kinetic model for both the formation and decay of ammonia-bound S2. The model predicts ammonia binds to S2 rapidly (t1/2 = 1 ms) with a large equilibrium constant. This finding implies that ammonia decreases the reduction potential of S2 by at least 2.7 kcal mol(-1) (>120 mV), which is not consistent with ammonia substitution of a terminal water ligand of Mn(IV). Instead, these data support the proposal that ammonia binds as a bridging ligand between two Mn atoms. Implications for the mechanism of O-O bond formation are discussed.

  2. Phosphate binders affect vitamin K concentration by undesired binding, an in vitro study.

    Science.gov (United States)

    Neradova, A; Schumacher, S P; Hubeek, I; Lux, P; Schurgers, L J; Vervloet, M G

    2017-05-02

    Vascular calcification is a major contributing factor to mortality in end stage renal disease (ESRD). Despite the efficacy of phosphate binders to improve hyperphosphatemia, data on vascular calcification are less clear. There seems to be a difference in attenuation or delay in progression between different binders. In this in vitro experiment we tested whether phosphate binders could limit bioavailability of vitamin K2 by undesired binding. Vitamin K-deficiency limits activation of the vascular tissue mineralization inhibitor matrix γ-carboxyglutamate (Gla) protein (MGP) thereby exacerbating vascular calcification. In this experiment vitamin K2 (menaquinone-7; MK-7) binding was assessed by adding 1 mg of vitamin K2 to a medium with pH 6 containing 67 mg phosphate binder with either 7 mg of phosphate or no phosphate. Five different phosphate binders were tested. After five and a half hours vitamin K was analyzed by HPLC. All experiments were performed in triplicate. Sucroferric-oxyhydroxide and sevelamer carbonate did not significantly bind vitamin K2, both in solution only containing vitamin K2 or in combination with phosphate. Calcium acetate/magnesium carbonate binds vitamin K2 strongly both in absence (p = 0.001) and presence of phosphate (p = 0.003). Lanthanum carbonate significantly binds vitamin K2 in solution containing only vitamin K2 (p = 0.005) whereas no significant binding of vitamin K2 was observed in the solution containing vitamin K2 and phosphate (p = 0.462). Calcium carbonate binds vitamin K2 significantly in a solution with vitamin K2 and phosphate (p = 0.009) whereas without phosphate no significant binding of vitamin K2 was observed (p = 0.123). Sucroferric-oxyhydroxide and sevelamer carbonate were the only binders of the five binders studied that did not bind vitamin K2 in vitro. The presence or absence of phosphate significantly interferes with vitamin K2 binding so phosphate binders could potentially limit

  3. In vitro DNA binding studies of lenalidomide using spectroscopic in combination with molecular docking techniques

    Science.gov (United States)

    Xu, Liang; Hu, Yan-Xi; Li, Yan-Cheng; Zhang, Li; Ai, Hai-Xin; Liu, Yu-Feng; Liu, Hong-Sheng

    2018-02-01

    In the present work, the binding interaction between lenalidomide (LEN) and calf thymus DNA (ct-DNA) was systematically studied by using fluorescence, ultraviolet-visible (UV-vis) absorption, circular dichroism (CD) spectroscopies under imitated physiological conditions (pH = 7.4) coupled with molecular docking. It was found that LEN was bound to ct-DNA with high binding affinity (Ka = 2.308 × 105 M-1 at 283 K) through groove binding as evidenced by a slight decrease in the absorption intensity in combination with CD spectra. Thermodynamic parameters (ΔG 0 and ΔS interaction. Furthermore, competitive binding experiments with ethidium bromide and 4‧, 6-dia-midino-2-phenylindoleas probes showed that LEN could preferentially bind in the minor groove of double-stranded DNA. The average lifetime of LEN was calculated to be 7.645 ns. The φ of LEN was measured as 0.09 and non-radiation energy transfer between LEN and DNA had occurred. The results of the molecular docking were consistent with the experimental results. This study explored the potential applicability of the spectroscopic properties of LEN and also investigated its interactions with relevant biological targets. In addition, it will provide some theoretical references for the deep research of simultaneous administration of LEN with other drugs.

  4. Radioligands for PET studies of central benzodiazepine receptors and PK (peripheral benzodiazepine) binding sites -current status

    International Nuclear Information System (INIS)

    Pike, V.W.; Osman, S.; Shah, F.; Turton, D.R.; Waters, S.L.; Crouzel, C.; Nutt, D.J.

    1993-01-01

    The status of the radiochemical development and biological evaluation of radioligands for PET studies of central benzodiazepine (BZ) receptors and the so-called peripheral benzodiazepine binding sites, here discriminated and referred to as PK binding sites, is reviewed against current pharmacological knowledge, indicating those agents with present value and those with future potential. Practical recommendations are given for the preparation of two useful radioligands for PET studies, [N-methyl- 11 C]flumazenil for central BZ receptors, and [N-methyl- 11 C]PK 11195 for PK binding sites. Quality assurance and plasma metabolite analysis are also reviewed for these radioligands and practical recommendations are given on methodology for their performance. (Author)

  5. Structural and kinetic study of an internal substrate binding site in dehaloperoxidase-hemoglobin A from Amphitrite ornata.

    Science.gov (United States)

    Zhao, Jing; de Serrano, Vesna; Zhao, Junjie; Le, Peter; Franzen, Stefan

    2013-04-09

    X-ray crystal structures of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata soaked with substrate, 2,4,6-tribromophenol (2,4,6-TBP), in buffer solvent with added methanol (MeOH), 2-propanol (2-PrOH), and dimethyl sulfoxide (DMSO) reveal an internal substrate binding site deep in the distal pocket above the α-edge of the heme that is distinct from the previously determined internal inhibitor binding site. The peroxidase function of DHP A has most often been studied using 2,4,6-trichlorophenol (2,4,6-TCP) as a substrate analogue because of the low solubility of 2,4,6-TBP in an aqueous buffer solution. Previous studies at low substrate concentrations pointed to the binding of substrate 2,4,6-TCP at an external site near the exterior heme β- or δ-edge as observed in the class of heme peroxidases. Here we report that the turnover frequencies of both substrates 2,4,6-TCP and 2,4,6-TBP deviate from Michaelis-Menten kinetics at high concentrations. The turnover frequency reaches a maximum in the range of 1400-1700 μM, with a decrease in rate at higher concentrations that is both substrate- and solvent-dependent. The X-ray crystal structure is consistent with the presence of an internal active site above the heme α-edge, in which the substrate would be oxidized in two consecutive steps inside the enzyme, followed by attack by H2O via a water channel in the protein. The physiological role of the internal site may involve interactions with any of a number of aromatic toxins found in benthic ecosystems where A. ornata resides.

  6. Binding interaction of phosphorus heterocycles with bovine serum albumin: A biochemical study

    Directory of Open Access Journals (Sweden)

    Swarup Roy

    2017-02-01

    Full Text Available Interaction between bovine serum albumin (BSA and phosphorus heterocycles (PHs was studied using multi-spectroscopic techniques. The results indicated the high binding affinity of PHs to BSA as it quenches the intrinsic fluorescence of BSA. The experimental data suggested the fluorescence quenching mechanism between PHs and BSA as a dynamic quenching. From the UV–vis studies, the apparent association constant (Kapp was found to be 9.25×102, 1.27×104 and 9.01×102 L/mol for the interaction of BSA with PH-1, PH-2 and PH-3 respectively. According to the Förster's non-radiation energy transfer (FRET theory, the binding distances between BSA and PHs were calculated. The binding distances (r of PH-1, PH-2 and PH-3 were found to be 2.86, 3.03, and 5.12 nm, respectively, indicating energy transfer occurs between BSA and PHs. The binding constants of the PHs obtained from the fluorescence quenching data were found to be decreased with increase of temperature. The negative values of the thermodynamic parameters ΔH, ΔS and ΔG at different temperatures revealed that the binding process is spontaneous; hydrogen bonds and van der Waals interaction were the main force to stabilize the complex. The microenvironment of the protein-binding site was studied by synchronous fluorescence and circular dichroism (CD techniques and data indicated that the conformation of BSA changed in the presence of PHs. Finally, we studied the BSA-PHs docking using Autodock and results suggest that PHs is located in the cleft between the domains of BSA.

  7. Study of Binding Properties Between Two New Ibuprofen and Naproxen Based Acyl Hydrazone Derivatives and Trypsin.

    Science.gov (United States)

    Gökoğlu, Elmas; Yılmaz, Esra; Gökoğlu, Esra; Baran, Ayşe Uzgören

    2016-01-01

    Two acyl hydrazone derivatives, AHI and AHN,made from ibuprofen and naproxen-derived hydrazides, were prepared and studied of binding properties with serine protease trypsin by UV-vis absorption and fluorescence quenching at pH 7.4. The results suggest that both hydrazones can interact strongly with trypsin and there are the formation of trypsin-hydrazone complexes. The Stern-Volmer constants, binding constants,binding sites and the corresponding thermodynamic parameters ΔH°, ΔS° and ΔG° were calculated at different temperatures.The effect of common metal ions on the constants was also discussed. The binding modes can be explained on the basis of hydrogen bonds and van der Waals forces. The binding distance(r) ~3 nm between the donor (trypsin) and acceptors (AHI and AHN) was obtained according to Förster's non-radiative energy transfer theory. Moreover, LOD and LOQ of hydrazones were calculated in the presence of trypsin.

  8. Binding of phosphorus-containing inhibitors to thermolysin studied by the Poisson-Boltzmann method.

    Science.gov (United States)

    Shen, J; Wendoloski, J

    1995-03-01

    Zinc endopeptidase thermolysin can be inhibited by a series of phosphorus-containing peptide analogues, Cbz-Gly-psi (PO2)-X-Leu-Y-R (ZGp(X)L(y)R), where X = NH, O, or CH2; Y = NH or O; R = Leu, Ala, Gly, Phe, H, or CH3. The affinity correlation as well as an X-ray crystallography study suggest that these inhibitors bind to thermolysin in an identical mode. In this work, we calculate the electrostatic binding free energies for a series of 13 phosphorus-containing inhibitors with modifications at X, Y, and R moieties using finite difference solution to the Poisson-Boltzmann equation. A method has been developed to include the solvation entropy changes due to binding different ligands to a macromolecule. We demonstrate that the electrostatic energy and empirically derived solvation entropy can account for most of the binding energy differences in this series. By analyzing the binding contribution from individual residues, we show that the energy of a hydrogen bond is not confined to the donor and acceptor. In particular, the positive charges on Zn and Arg 203, which are not the acceptors, contribute significantly to the hydrogen bonds between two amides of ZGpLL and the thermolysin.

  9. Alteration of methotrexate binding to human serum albumin induced by oxidative stress. Spectroscopic comparative study.

    Science.gov (United States)

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

    2016-01-05

    Changes of oxidative modified albumin conformation by comparison of non-modified (HSA) and modified (oHSA) human serum albumin absorption spectra, Red Edge Excitation Shift (REES) effect and fluorescence synchronous spectra were investigated. Studies of absorption spectra indicated that changes in the value of absorbance associated with spectral changes in the region from 200 to 250nm involve structural alterations related to variations in peptide backbone conformation. Analysis of the REES effect allowed for the observation of changes caused by oxidation in the region of the hydrophobic pocket containing the tryptophanyl residue. Synchronous fluorescence spectroscopy confirmed changes of the position of the tryptophanyl and tyrosil residues fluorescent band. Effect of oxidative stress on binding of methotrexate (MTX) was investigated by spectrofluorescence, UV-VIS and (1)HNMR spectroscopy. MTX caused the fluorescence quenching of non-modified (HSA) and modified (oHSA) human serum albumin molecule. The values of binding constants, Hill's coefficients and a number of binding sites in the protein molecule in the high affinity binding site were calculated for the binary MTX-HSA and MTX-oHSA systems. For these systems, qualitative analysis in the low affinity binding sites was performed with the use of the (1)HNMR technique. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A Study on Bone Mass in Elderly Chinese Foot-Binding Women

    Directory of Open Access Journals (Sweden)

    Yi Pan

    2013-01-01

    Full Text Available The aim of this study is to understand the influences of the social custom of foot binding on female osteoporosis by means of comparing and analyzing the lumbar vertebrae and hip bone mass differences between the foot-binding aged women and unbound women of the same age at Qujing District of Yunnan Province. Of the examined people, 81.37% suffer from osteoporosis on the basis of lumbar vertebra (L1–L4 and femoral neck BMD, of which 82.14% for the foot-binding group and 80.44% for the unbound group. There is no statistical difference for the osteoporosis morbidity of the two groups. Compare the BMD value for various vertebrae, femoral neck, and rehabilitation of the two groups and find the BMD value for the other parts have no statistical difference except the BMD value of L1 centrum, which shows that foot binding does not significantly influence the overall bone mineral density of foot-binding women.

  11. Synthesis and receptor binding studies of (+/-)1-iodo-MK-801

    International Nuclear Information System (INIS)

    Yang, D.J.; Ciliax, B.J.; Van Dort, M.E.; Gildersleeve, D.; Pirat, J.L.; Young, A.B.; Wieland, D.M.

    1989-01-01

    The glutamate analogue N-methyl-D-aspartate (NMDA) binds to a subset of glutamate receptors that are coupled to a voltage-sensitive cation channel. This NMDA-linked channel is the likely binding locus of the potent anticonvulsant MK-801. To develop single-photon emission computed tomography (SPECT) probes of this brain channel, we synthesized (+/)1-iodo-MK-801 and (+/-)1-[ 125 I]iodo-MK-801. The effect of (+/-)1-iodo-MK-801 on ligand binding to the NMDA-linked glutamate receptor site was assessed using a rat brain homogenate assay. (+/-)1-Iodo-MK-801 displaced the dissociative anesthetic ligand [ 3 H]N-[1-(2-thienyl)cyclohexyl]piperidine ([ 3 H]TCP) binding with an IC50 of 1 microM, which is a 10-fold lower binding affinity than that of (+/-)MK-801. In in vivo autoradiographic studies, (+/-)MK-801 failed to block selective uptake of (+/-)1-iodo-MK-801 in rat brain. These results suggest that (+/-)1-iodo-MK-801 may not be a suitable ligand for mapping NMDA-linked glutamate receptor channels

  12. Studying binding specificities of peptide recognition modules by high-throughput phage display selections.

    Science.gov (United States)

    Huang, Haiming; Sidhu, Sachdev S

    2011-01-01

    Peptide recognition modules (PRMs) play critical roles in cellular processes, including differentiation, proliferation and cytoskeleton organization. PRMs normally bind to short linear motifs in protein ligands, and by so doing recruit proteins into signaling complexes. Based on the binding specificity profile of a PRM, one can predict putative natural interaction partners by searching genome databases. Candidate interaction partners can in turn provide clues to assemble potential in vivo protein complexes that the PRM may be involved with. Combinatorial peptide libraries have proven to be effective tools for profiling the binding specificities of PRMs. Herein, we describe high-throughput methods for the expression and purification of PRM proteins and the use of peptide-phage libraries for PRM specificity profiling. These high-throughput methods greatly expedite the study of PRM families on a genome-wide scale.

  13. Binding of phosphorus-containing inhibitors to thermolysin studied by the Poisson-Boltzmann method.

    OpenAIRE

    Shen, J.; Wendoloski, J.

    1995-01-01

    Zinc endopeptidase thermolysin can be inhibited by a series of phosphorus-containing peptide analogues, Cbz-Gly-psi (PO2)-X-Leu-Y-R (ZGp(X)L(y)R), where X = NH, O, or CH2; Y = NH or O; R = Leu, Ala, Gly, Phe, H, or CH3. The affinity correlation as well as an X-ray crystallography study suggest that these inhibitors bind to thermolysin in an identical mode. In this work, we calculate the electrostatic binding free energies for a series of 13 phosphorus-containing inhibitors with modifications ...

  14. Iron hexacyanide/cytochrome-C - intramolecular electron transfer and binding constants - (pulse radiolytic study). Progress report

    International Nuclear Information System (INIS)

    Ilan, Y.; Shafferman, A.

    Internal oxidation and reduction rates of horse cytochrome-c in the complexes, CII.Fe/sup III/(CN) -3 6 and CIII.Fe/sup II/(CN) -4 6 , are 4.6.10 4 s -1 and 3.3.10 2 s -1 , respectively. The binding sites of the iron hexacyanide ions on either CII or CIII are kinetically almost indistinguishable; binding constants range from 0.87.10 3 to 2.10 3 M -1 . The present pulse radiolytic kinetic data are compared with that from N.M.R, T-jump and equilibrium dialysis studies

  15. Polychlorinated biphenyl exposure, diabetes and endogenous hormones: a cross-sectional study in men previously employed at a capacitor manufacturing plant.

    Science.gov (United States)

    Persky, Victoria; Piorkowski, Julie; Turyk, Mary; Freels, Sally; Chatterton, Robert; Dimos, John; Bradlow, H Leon; Chary, Lin Kaatz; Burse, Virlyn; Unterman, Terry; Sepkovic, Daniel W; McCann, Kenneth

    2012-08-29

    Studies have shown associations of diabetes and endogenous hormones with exposure to a wide variety of organochlorines. We have previously reported positive associations of polychlorinated biphenyls (PCBs) and inverse associations of selected steroid hormones with diabetes in postmenopausal women previously employed in a capacitor manufacturing plant. This paper examines associations of PCBs with diabetes and endogenous hormones in 63 men previously employed at the same plant who in 1996 underwent surveys of their exposure and medical history and collection of bloods and urine for measurements of PCBs, lipids, liver function, hematologic markers and endogenous hormones. PCB exposure was positively associated with diabetes and age and inversely associated with thyroid stimulating hormone and triiodothyronine-uptake. History of diabetes was significantly related to total PCBs and all PCB functional groupings, but not to quarters worked and job score, after control for potential confounders. None of the exposures were related to insulin resistance (HOMA-IR) in non-diabetic men. Associations of PCBs with specific endogenous hormones differ in some respects from previous findings in postmenopausal women employed at the capacitor plant. Results from this study, however, do confirm previous reports relating PCB exposure to diabetes and suggest that these associations are not mediated by measured endogenous hormones.

  16. Characterization of the novel progestin gestodene by receptor binding studies and transactivation assays.

    Science.gov (United States)

    Fuhrmann, U; Slater, E P; Fritzemeier, K H

    1995-01-01

    Gestodene is a novel progestin used in oral contraceptives with an increased separation of progestogenic versus androgenic activity and a distinct antimineralocorticoid activity. This specific pharmacological profile of gestodene is defined by its pattern of binding affinities to a variety of steroid hormone receptors. In the present study the affinity of gestodene to the progesterone receptor (PR), the androgen receptor (AR), the glucocorticoid receptor (GR), the mineralocorticoid receptor (MR) and the estrogen receptor (ER) was re-evaluated by steroid binding assays and compared to those obtained for 3-keto-desogestrel and progesterone. The two synthetic progestins displayed identical high affinity to rabbit PR and similar marked binding to rat AR and GR, while progesterone showed high affinity to PR but only low binding to AR and GR. Furthermore, 3-keto-desogestrel exhibited almost no binding to MR, whereas gestodene, similar to progesterone, showed marked affinity to this receptor. In addition to receptor binding studies, transactivation assays were carried out to investigate the effects of gestodene on AR-, GR- and MR-mediated induction of transcription. In contrast to progesterone, which showed antiandrogenic activity, gestodene and 3-keto-desogestrel both exhibited androgenic activity. Furthermore, all three progestins exhibited weak GR-mediated antagonistic activity. In contrast to progesterone, which showed almost no glucocorticoid activity, gestodene and 3-keto-desogestrel showed weak glucocorticoid action. In addition, gestodene inhibited the aldosterone-induced reporter gene transcription, similar to progesterone, whereas unlike progesterone, gestodene did not induce reporter gene transcription. 3-Keto-desogestrel showed neither antimineralocorticoid nor mineralocorticoid action.

  17. Binding Studies of a Spin-Labelled Oxidized Coenzyme to Bovine-Liver Glutamate Dehydrogenase

    NARCIS (Netherlands)

    Zantema, Alt; Trommer, Wolfgang E.; Wenzel, Herbert; Robillard, George T.

    1977-01-01

    NAD+ with a nitroxide piperidine ring linked to the NH2 group of the adenine possesses full coenzymatic activity with glutamate dehydrogenase. Electron spin resonance spectra in the presence of glutamate dehydrogenase show mixtures of free and strongly immobilized spin-label. Binding studies in

  18. Quantum confined Stark effect in Gaussian quantum wells: A tight-binding study

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Morales, A.; Martínez-Orozco, J. C.; Rodríguez-Vargas, I. [Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac. (Mexico)

    2014-05-15

    The main characteristics of the quantum confined Stark effect (QCSE) are studied theoretically in quantum wells of Gaussian profile. The semi-empirical tight-binding model and the Green function formalism are applied in the numerical calculations. A comparison of the QCSE in quantum wells with different kinds of confining potential is presented.

  19. A model for the study of electrostatic binding between a pair of ...

    African Journals Online (AJOL)

    A model for the study of electrostatic binding between a pair of molecules at large distances. A Umar, G Hussin. Abstract. No Abstract. Nigerian Journal of Chemical Research Vol 5 2000: 1-9. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  20. Protein binding studies with radiolabeled compounds containing radiochemical impurities. Equilibrium dialysis versus dialysis rate determination

    DEFF Research Database (Denmark)

    Honoré, B

    1987-01-01

    The influence of radiochemical impurities in dialysis experiments with high-affinity ligands is investigated. Albumin binding of labeled decanoate (97% pure) is studied by two dialysis techniques. It is shown that equilibrium dialysis is very sensitive to the presence of impurities resulting...

  1. Studies on two calcium-binding proteins from squid optic lobe

    International Nuclear Information System (INIS)

    Sheldon, A.

    1988-01-01

    Investigations focused on the physicochemical and functional properties of squid calcium-binding protein (SCaBP) and squid calmodulin (SCaM). The physiochemical studies included characterization of Ca 2+ - and Mg 2+ -binding properties, and the effects of metal ion-binding on protein conformation. These studies were performed using various ionic conditions, including those physiological for the squid. Ca 2+ -binding by SCaBP, SCaM, and bovine brain calmodulin (BCaM) (for comparison) was measured by equilibrium dialysis. All three proteins bound 4 Ca 2+ per mol protein under each set of ionic conditions. Under conditions physiological for the squid, both the squid proteins bound Ca 2+ over a similar range of free Ca 2+ concentrations. Ca 2+ - and Mg 2+ -induced changes in the conformation of the proteins were studied by polyacrylamide gel electrophoresis, fluphenazine-Sepharose affinity chromatography, and ultraviolet absorption difference spectroscopy. The functional studies focused on the identification of squid optic lobe proteins which interacted with SCaBP and SCaM in a Ca 2+ - dependent manner. These proteins were identified by SCaBP- and SCaM-Sepharose affinity chromatography, an immunoblotting technique using a polyclonal anti-SCaBP antibody, and a 125 I-calmodulin overlay procedure

  2. In-depth study of DNA binding of Cys2His2 finger domains in testis zinc-finger protein.

    Directory of Open Access Journals (Sweden)

    Chun-Chi Chou

    Full Text Available Previously, we identified that both fingers 1 and 2 in the three Cys2His2 zinc-finger domains (TZD of testis zinc-finger protein specifically bind to its cognate DNA; however, finger 3 is non-sequence-specific. To gain insights into the interaction mechanism, here we further investigated the DNA-binding characteristics of TZD bound to non-specific DNAs and its finger segments bound to cognate DNA. TZD in non-specific DNA binding showed smaller chemical shift perturbations, as expected. However, the direction of shift perturbation, change of DNA imino-proton NMR signal, and dynamics on the 15N backbone atom significantly differed between specific and non-specific binding. Using these unique characteristics, we confirmed that the three single-finger segments (TZD1, TZD2 and TZD3 and the two-finger segment (TZD23 non-specifically bind to the cognate DNA. In comparison, the other two-finger segment (TZD12 binding to the cognate DNA features simultaneous non-specific and semi-specific binding, both slowly exchanged in terms of NMR timescale. The process of TZD binding to the cognate DNA is likely stepwise: initially TZD non-specifically binds to DNA, then fingers 1 and 2 insert cooperatively into the major groove of DNA by semi-specific binding, and finally finger 3 non-specifically binds to DNA, which promotes the specific binding on fingers 1 and 2 and stabilizes the formation of a specific TZD-DNA complex.

  3. Study of some physical aspects previous to design of an exponential experiment; Estudio de algunos aspectos fisicos previos al diseno de una experiencia exponencial

    Energy Technology Data Exchange (ETDEWEB)

    Caro, R.; Francisco, J. L. de

    1961-07-01

    This report presents the theoretical study of some physical aspects previous to the design of an exponential facility. The are: Fast and slow flux distribution in the multiplicative medium and in the thermal column, slowing down in the thermal column, geometrical distribution and minimum needed intensity of sources access channels and perturbations produced by possible variations in its position and intensity. (Author) 4 refs.

  4. Quantifying the influence of previously burned areas on suppression effectiveness and avoided exposure: A case study of the Las Conchas Fire

    Science.gov (United States)

    Matthew P. Thompson; Patrick Freeborn; Jon D. Rieck; Dave Calkin; Julie W. Gilbertson-Day; Mark A. Cochrane; Michael S. Hand

    2016-01-01

    We present a case study of the Las Conchas Fire (2011) to explore the role of previously burned areas (wildfires and prescribed fires) on suppression effectiveness and avoided exposure. Methodological innovations include characterisation of the joint dynamics of fire growth and suppression activities, development of a fire line effectiveness framework, and...

  5. Perturbation of lipids and glucose metabolism associated with previous 2,4-D exposure: a cross-sectional study of NHANES III data, 1988-1994

    Science.gov (United States)

    Background Results from previous population studies showed that mortality rates from acute myocardial infarction and type-2 diabetes during the 1980s and 1990s in rural, agricultural counties of Minnesota, Montana, North and South Dakota, were higher in counties with a higher le...

  6. Studies on folate binding and a radioassay for serum and whole-blood folate using goat milk as binding agent

    International Nuclear Information System (INIS)

    Piyasena, R.D.; Weerasekera, D.A.; Hettiaratchi, N.; Wikramanayake, T.W.

    1978-01-01

    Preparations of cow, goat, buffalo and human milk in addition to pig plasma were tested for folate binding properties. Of these, only pig plasma and goat milk showed sufficient binding to enable them to be used as binding agents in a radioassay for serum and whole-blood folate. The binding of folate by cow milk preparations in particular was found to be very poor. Goat milk was preferred to pig plasma as a binder for folate radioassay for reasons of convenience, economy and greater stability, and because pteroylglutamic acid (PGA) can be used both as tracer and standard. Where pig plasma is used with the inclusion of folate-free serum in the standard tubes, differences were observed between the standard and serum blanks which themselves varied from sample to sample. By contrast, with goat milk, all blank readings were normally 3% or less. Five out of eight samples of goat milk were seen to contain 'releasing factor' necessary to liberate folate from endogenous binder (FABP). Where present, the factor was found to be stable for at least three months when the partially purified milk was stored freeze dried at 4 0 C. Goat milk binder was found unable to distinguish between PGA and methyltetrahydrofolic acid (MTFA) at pH9.3. This enabled PGA rather than the more unstable MTFA to be used as tracer and standard. The assay employs a one-step incubation procedure at room temperature. It is sensitive to about 0.1 ng of PGA and is reproducible to less than 5% variation. The mean % recovery of inactive added folate was 101+-4%. (author)

  7. Structural and binding studies of a C-type galactose-binding lectin from Bothrops jararacussu snake venom.

    Science.gov (United States)

    Sartim, Marco A; Pinheiro, Matheus P; de Pádua, Ricardo A P; Sampaio, Suely V; Nonato, M Cristina

    2017-02-01

    BJcuL is a snake venom galactoside-binding lectin (SVgalL) isolated from Bothrops jararacussu and is involved in a wide variety of biological activities including triggering of pro-inflammatory response, disruption of microbial biofilm structure and induction of apoptosis. In the present work, we determined the crystallographic structure of BJcuL, the first holo structure of a SVgalL, and introduced the fluorescence-based thermal stability assay (Thermofluor) as a tool for screening and characterization of the binding mechanism of SVgalL ligands. BJcuL structure revealed the existence of a porous and flexible decameric arrangement composed of disulfide-linked dimers related by a five-fold symmetry. Each monomer contains the canonical carbohydrate recognition domain, a calcium ion required for BJcuL lectinic activity and a sodium ion required for protein stabilization. BJcuL thermostability was found to be induced by calcium ion and galactoside sugars which exhibit hyperbolic saturation profiles dependent on ligand concentration. Serendipitously, the gentamicin group of aminoglycoside antibiotics (gAGAs) was also identified as BJcuL ligands. On contrast, gAGAs exhibited a sigmoidal saturation profile compatible with a cooperative mechanism of binding. Thermofluor, hemagglutination inhibition assay and molecular docking strategies were used to identify a distinct binding site in BJcuL localized at the dimeric interface near the fully conserved intermolecular Cys86-Cys86 disulfide bond. The hybrid approach used in the present work provided novel insights into structural behavior and functional diversification of SVgaLs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Bovine Chymosin: A Computational Study of Recognition and Binding of Bovine κ-Casein

    DEFF Research Database (Denmark)

    Palmer, David S.; Christensen, Anders Uhrenholt; Sørensen, Jesper

    2010-01-01

    Bovine chymosin is an aspartic protease that selectively cleaves the milk protein κ-casein. The enzyme is widely used to promote milk clotting in cheese manufacturing. We have developed models of residues 97-112 of bovine κ-casein complexed with bovine chymosin, using ligand docking, conformation......) is found to be important for stabilizing the binding pose. The catalytic site (including the catalytic water molecule) is stable in the starting conformation of the previously proposed general acid/base catalytic mechanism for 18 ns of molecular dynamics simulations......Bovine chymosin is an aspartic protease that selectively cleaves the milk protein κ-casein. The enzyme is widely used to promote milk clotting in cheese manufacturing. We have developed models of residues 97-112 of bovine κ-casein complexed with bovine chymosin, using ligand docking, conformational...... search algorithms, and molecular dynamics simulations. In agreement with limited experimental evidence, the model suggests that the substrate binds in an extended conformation with charged residues on either side of the scissile bond playing an important role in stabilizing the binding pose. Lys111...

  9. Studies on the digitalis binding site in Na, K-ATPase

    International Nuclear Information System (INIS)

    Ahmed, K.; McParland, R.; Becker, R.; From, A.; Schimerlik, M.; Fullerton, D.S.

    1986-01-01

    Na, K-ATPase is believed to be the receptor for digitalis glycosides. The authors have previously documented that C17 side group of the cardenolide molecule is crucial to α subunit receptor binding. They have attempted to identify the structure of this binding site by labelling the enzyme with a 3 H-labelled photoactive probe localized in the C17 side group of the genin molecule. 3 H-α-subunit was purified and subjected to tryptic digestion. The digest was fractionated by gel filtration on Sephadex G-100. Fractions containing 3 H-labelled peptide were pooled and rechromatographed. The central peak fractions of 3 H-peptide were pooled, analyzed by SDS-PAGE, and subjected to amino acid sequence analysis. The tryptic peptide containing the 3 H-probe showed considerable sequence heterogeneity. Comparison of the sequence data with the published cDNA-based α-subunit sequence revealed that this peptide material was indeed a mixture of two tryptic peptides of nearly identical size containing the sequences from residue 68 through residue 146, and residues 263 through 342. The latter peptide contains the sequence ... glu tyr thr try leu glu ... speculated by Shull et al. as a possible ouabain binding site

  10. Photoelectron Spectroscopy and Theoretical Studies of Anion-pi Interactions: Binding Strength and Anion Specificity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian; Zhou, Bin; Sun, Zhenrong; Wang, Xue B.

    2015-01-01

    Proposed in theory and confirmed to exist, anion–π interactions have been recognized as new and important non-covalent binding forces. Despite extensive theoretical studies, numerous crystal structural identifications, and a plethora of solution phase investigations, intrinsic anion–π interaction strengths that are free from complications of condensed phases’ environments, have not been directly measured in the gas phase. Herein we present a joint photoelectron spectroscopic and theoretical study on this subject, in which tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic was used as a charge-neutral molecular host to probe its interactions with a series of anions with distinctly different shapes and charge states (spherical halides Cl⁻, Br⁻, I⁻, linear thiocyanate SCN⁻, trigonal planar nitrate NO₃⁻, pyramidic iodate IO₃⁻, and tetrahedral sulfate SO₄²⁻). The binding energies of the resultant gaseous 1:1 complexes (1•Cl⁻,1•Br⁻, 1•I⁻, 1•SCN⁻, 1•NO₃⁻, 1•IO₃⁻ and 1•SO₄²⁻) were directly measured experimentally, exhibiting substantial non-covalent interactions with pronounced anion specific effects. The binding strengths of Cl⁻, NO₃⁻, IO₃⁻ with 1 are found to be strongest among all singly charged anions, amounting to ca. 30 kcal/mol, but only about 40% of that between 1 and SO₄²⁻. Quantum chemical calculations reveal that all anions reside in the center of the cavity of 1 with anion–π binding motif in the complexes’ optimized structures, where 1 is seen to be able to self-regulate its cavity structure to accommodate anions of different geometries and three-dimensional shapes. Electron density surface and natural bond orbital charge distribution analysis further support anion–π binding formation. The calculated binding energies of the anions and 1 nicely reproduce the experimentally estimated electron binding energy increase. This work

  11. Spectroscopy and molecular docking studies on the binding of propyl gallate to human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guo-fei; Wang, Yu; Xi, Lei; Liu, Jin; Wang, Hao; Du, Lin-fang, E-mail: dulinfang@scu.edu.cn

    2015-03-15

    The interaction of propyl gallate (PG) with human serum albumin (HSA) was investigated by fluorescence, far-UV CD and FT-IR spectroscopic methods as well as molecular docking. Fluorescence emission spectra demonstrated that the HSA fluorescence was quenched by PG through static quenching and energy transfer with the binding constants in the order of 10{sup 5} L mol{sup −1}. The thermodynamic parameters (ΔH=−29.64 KJ mol{sup −1}, ΔS=2.7 J mol{sup −1} K{sup −1}) indicated that both hydrophobic force and hydrogen bond interactions played a leading role in the formation of PG–HSA complex. The results also showed the existence of a single binding site, which was located in subdomain IIA (site I) as revealed by molecular docking and competitive binding experiments. Molecular docking studies further showed the participation of several amino acids in PG–HSA complexation, which stabilized by H-bonding systems. The synchronous fluorescence spectra showed that the binding of drug caused the environment of tryptophan residues became more polar. FT-IR and CD spectroscopic further showed that drug complexation altered protein conformation by a major reduction of α-helix inducing a partial protein destabilization. - Highlights: • The interaction between propyl gallate and HSA has been investigated. • HSA fluorescence is quenched by propyl gallate through static quenching mechanism. • Both hydrophobic force and hydrogen bond play major role in the binding process. • Site I of the HSA is found to be the main binding site for propyl gallate. • The structure of HSA has been changed upon the interaction with propyl gallate.

  12. Escherichia coli Single-Stranded DNA-Binding Protein: NanoESI-MS Studies of Salt-Modulated Subunit Exchange and DNA Binding Transactions

    Science.gov (United States)

    Mason, Claire E.; Jergic, Slobodan; Lo, Allen T. Y.; Wang, Yao; Dixon, Nicholas E.; Beck, Jennifer L.

    2013-02-01

    Single-stranded DNA-binding proteins (SSBs) are ubiquitous oligomeric proteins that bind with very high affinity to single-stranded DNA and have a variety of essential roles in DNA metabolism. Nanoelectrospray ionization mass spectrometry (nanoESI-MS) was used to monitor subunit exchange in full-length and truncated forms of the homotetrameric SSB from Escherichia coli. Subunit exchange in the native protein was found to occur slowly over a period of hours, but was significantly more rapid in a truncated variant of SSB from which the eight C-terminal residues were deleted. This effect is proposed to result from C-terminus mediated stabilization of the SSB tetramer, in which the C-termini interact with the DNA-binding cores of adjacent subunits. NanoESI-MS was also used to examine DNA binding to the SSB tetramer. Binding of single-stranded oligonucleotides [one molecule of (dT)70, one molecule of (dT)35, or two molecules of (dT)35] was found to prevent SSB subunit exchange. Transfer of SSB tetramers between discrete oligonucleotides was also observed and is consistent with predictions from solution-phase studies, suggesting that SSB-DNA complexes can be reliably analyzed by ESI mass spectrometry.

  13. Cytochrome P450 2C9 Type II Binding Studies on Quinoline-4-carboxamide Analogs

    Science.gov (United States)

    Peng, Chi-Chi; Cape, Jonathan L.; Rushmore, Tom; Crouch, Gregory J.; Jones, Jeffrey P.

    2009-01-01

    CYP2C9 is a significant P450 protein responsible for drug metabolism. With the increased use of heterocyclic compounds in drug design, a rapid and efficient pre-drug screening of these potential type II binding compounds is essential to avoid adverse drug reactions. To understand binding modes, we use quinoline-4-carboxamide analogs to study the factors that determine the structure-activity relationships. The results of this study suggest that the more accessible pyridine with the nitrogen para to the linkage can coordinate directly with the ferric heme iron, but this is not seen for the meta or ortho isomers. The π-cation interaction of the naphthalene moiety and Arg 108 residue may also assist in stabilizing substrate binding within the active-site cavity. The type II substrate binding affinity is determined by the combination of steric, electrostatic, and hydrophobicity factors; meanwhile, it is enhanced by the strength of lone pair electrons coordination with the heme iron. PMID:19053752

  14. DNA-binding, DNA cleavage and cytotoxicity studies of two anthraquinone derivatives.

    Science.gov (United States)

    Gholivand, M B; Kashanian, S; Peyman, H

    2012-02-15

    The interaction of native calf thymus DNA (CT-DNA) with two anthraquinones including quinizarin (1,4-dihydroxy anthraquinone) and danthron (1,8-dihydroxy anthraquinone) in a mixture of 0.04M Brittone-Robinson buffer and 50% of ethanol were studied at physiological pH by spectrofluorometric and cyclic voltammetry techniques. The former technique was used to calculate the binding constants of anthraquinones-DNA complexes at different temperatures. Thermodynamic study indicated that the reactions of both anthraquinone-DNA systems are predominantly entropically driven. Furthermore, the binding mechanisms on the reaction of the two anthraquinones with DNA and the effect of ionic strength on the fluorescence property of the system have also been investigated. The results of the experiments indicated that the binding modes of quinizarin and danthron with DNA were evaluated to be groove binding. Moreover, the cytotoxic activity of both compounds against human chronic myelogenous leukemia K562 cell line and DNA cleavage were investigated. The results indicated that these compounds slightly cleavage pUC18 plasmid DNA and showed minor antitumor activity against K562 (human chronic myeloid leukemia) cell line. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Autolytic Activity and Plasma Binding Study of Aap, a Novel Minor Autolysin of Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    Ramina Mahboobi

    2016-04-01

    Full Text Available Pneumococcal autolysins are enzymes involved in cell wall turnover and cellular division physiologically. They have been found to be involved in the pneumococcus pathogenesis. The aim of this study was to identify the autolytic activity of Spr1754 as a novel protein of Streptococcus pneumoniae. Moreover, the binding of the recombinant protein to plasma proteins was also determined. The spr1754 gene was amplified by PCR and cloned into the pET21a(+ prokaryotic expression vector. The constructed pET21a(+/spr1754 recombinant plasmid was transformed into E. coli Origami (DE3 and induced using IPTG. The recombinant protein of Spr1754 was purified by Ni-NTA affinity chromatography and confirmed by SDS-PAGE and Western blot analysis using anti-His tag monoclonal antibody. Autolytic activity and the ability of the recombinant protein in binding to plasma proteins were performed using zymogram analysis and western blot, respectively. The spr1754 with expected size was cloned and overexpressed in Escherichia coli Origami (DE3, successfully. After purification of the Spr1754 recombinant protein, the autolytic activity was observed by zymography. Of the four plasma proteins used in this study, binding of lactoferrin to Spr1754 recombinant protein was shown. The Spr1754 recombinant protein has a bifunctional activity, i.e., as being autolysin and lactoferrin binding and designated as Aap (autolytic/ adhesion/ pneumococcus. Nevertheless, characterization of the Aap needs to be followed using gene inactivation and cell wall localization.

  16. A cross-sectional study of tuberculosis drug resistance among previously treated patients in a tertiary hospital in Accra, Ghana: public health implications of standardized regimens.

    Science.gov (United States)

    Forson, Audrey; Kwara, Awewura; Kudzawu, Samuel; Omari, Michael; Otu, Jacob; Gehre, Florian; de Jong, Bouke; Antonio, Martin

    2018-04-02

    Mycobacterium tuberculosis drug resistance is a major challenge to the use of standardized regimens for tuberculosis (TB) therapy, especially among previously treated patients. We aimed to investigate the frequency and pattern of drug resistance among previously treated patients with smear-positive pulmonary tuberculosis at the Korle-Bu Teaching Hospital Chest Clinic, Accra. This was a cross-sectional survey of mycobacterial isolates from previously treated patients referred to the Chest Clinic Laboratory between October 2010 and October 2013. The Bactec MGIT 960 system for mycobactrerial culture and drug sensitivity testing (DST) was used for sputum culture of AFB smear-positive patients with relapse, treatment failure, failure of smear conversion, or default. Descriptive statistics were used to summarize patient characteristics, and frequency and patterns of drug resistance. A total of 112 isolates were studied out of 155 from previously treated patients. Twenty contaminated (12.9%) and 23 non-viable isolates (14.8%) were excluded. Of the 112 studied isolates, 53 (47.3%) were pan-sensitive to all first-line drugs tested Any resistance (mono and poly resistance) to isoniazid was found in 44 isolates (39.3%) and any resistance to streptomycin in 43 (38.4%). Thirty-one (27.7%) were MDR-TB. Eleven (35.5%) out of 31 MDR-TB isolates were pre-XDR. MDR-TB isolates were more likely than non-MDR isolates to have streptomycin and ethambutol resistance. The main findings of this study were the high prevalence of MDR-TB and streptomycin resistance among previously treated TB patients, as well as a high prevalence of pre-XDR-TB among the MDR-TB patients, which suggest that first-line and second-line DST is essential to aid the design of effective regimens for these groups of patients in Ghana.

  17. Acute S-ketamine application does not alter cerebral [18F]altanserin binding: a pilot PET study in humans

    International Nuclear Information System (INIS)

    Matusch, A.; Rota Kops, E.; Winz, O.H.; Elmenhorst, D.; Herzog, H.; Hurlemann, R.; Zilles, K.; Bauer, A.

    2007-01-01

    Modeling short-term psychotic states with subanaesthetic doses of ketamine provides substantial experimental evidence in support of the glutamate hypothesis of schizophrenia. Ketamine exerts its pharmacological effects both directly via interactions with glutamate receptors and indirectly by stimulating presynaptic release of endogenous serotonin (5-HT). The aim of this feasibility study was to examine whether acute ketamine-induced 5-HT release interferes with the binding of the 5-HT 2A receptor (5-HT 2A R) radioligand [ 18 F]altanserin and positron emission tomography (PET). Two subjects treated with ketamine and one subject treated with placebo underwent [ 18 F]altanserin PET at distribution equilibrium conditions. Robust physiological, psychopathological and cognitive effects were present at ketamine plasma concentrations exceeding 100 μg/l during >70 min. Notwithstanding, we observed stable radioligand binding (changes ±95 % CI of -1.0 ± 1.6 % and +4.1 ± 1.8 % versus -1.2 ± 2.6 %) in large cortical regions presenting high basal uptake of both, [ 18 F]altanserin and ketamine. Marginal decreases of 4 % of radioligand binding were observed in the frontal lobe, and 8 % in a posteriorly specified frontomesial subregion. This finding is not compatible with a specific radioligand displacement from 5-HT2 AR which should occur proportionally throughout the whole brain. Instead, the spatial pattern of these minor reductions was congruent with ketamine-induced increases in cerebral blood flow observed in a previous study using [ 15 O]butanol PET. This may caused by accelerated clearance of unspecifically bound [ 18 F]altanserin from cerebral tissue with increased perfusion. In conclusion, this study suggests that [ 18 F]altanserin PET is not sensitive to acute neurotransmitter fluctuations under ketamine. Advantageously, the stability of [ 18 F]altanserin PET towards acute influences is a prerequisite for its future use to detect sub-acute and chronic effects of

  18. Cultured bovine brain capillary endothelial cells (BBCEC) - a blood-brain barrier model for studying the binding and internalization of insulin and insulin-like growth factor 1

    International Nuclear Information System (INIS)

    Keller, B.T.; Borchardt, R.T.

    1987-01-01

    Cultured bovine brain capillary endothelial cells (BBCEC) have previously been reported by their laboratory as a working model for studying nutrient and drug transport and metabolism at the blood-brain barrier. In the present study, they have utilized this culture system to investigate the binding and internalization of [ 125 I]-labelled insulin (INS) and insulin-like growth factor 1(IGF-1) by BBCEC. After 2 hrs at 23 0 C, the specific binding of INS and IGF-1 was 1.6% and 13.6%, respectively. At 37 0 C, the maximum specific binding was 0.9% for INS and 5.8% for IGF-1. Using an acid-wash technique to assess peptide internalization, it was observed that, at 37 0 C, approximately 60% of the bound INS rapidly became resistant to acid treatment, a value which was constant over 2 hr. With IGF-1, a similar proportion of the bound material, 62%, became resistant by 30 min, but subsequently decreased to 45% by 2 hr. Scatchard analysis of competitive binding studies indicated the presence of two binding sites for each protein, having K/sub d/'s of 0.82 nM and 19.2 nM for INS and 0.39 nM and 3.66 nM for IGF-1. Little change in the amount of INS binding was observed over a four-day interval as the cultures became a confluent monolayer. The present report of binding and internalization of these proteins suggests that the BBCEC may utilize a receptor-mediated process to internalize and/or transport (transcytosis) INS and IGF-1 from the circulation

  19. Combining modelling and mutagenesis studies of synaptic vesicle protein 2A to identify a series of residues involved in racetam binding.

    Science.gov (United States)

    Shi, Jiye; Anderson, Dina; Lynch, Berkley A; Castaigne, Jean-Gabriel; Foerch, Patrik; Lebon, Florence

    2011-10-01

    LEV (levetiracetam), an antiepileptic drug which possesses a unique profile in animal models of seizure and epilepsy, has as its unique binding site in brain, SV2A (synaptic vesicle protein 2A). Previous studies have used a chimaeric and site-specific mutagenesis approach to identify three residues in the putative tenth transmembrane helix of SV2A that, when mutated, alter binding of LEV and related racetam derivatives to SV2A. In the present paper, we report a combined modelling and mutagenesis study that successfully identifies another 11 residues in SV2A that appear to be involved in ligand binding. Sequence analysis and modelling of SV2A suggested residues equivalent to critical functional residues of other MFS (major facilitator superfamily) transporters. Alanine scanning of these and other SV2A residues resulted in the identification of residues affecting racetam binding, including Ile273 which differentiated between racetam analogues, when mutated to alanine. Integrating mutagenesis results with docking analysis led to the construction of a mutant in which six SV2A residues were replaced with corresponding SV2B residues. This mutant showed racetam ligand-binding affinity intermediate to the affinities observed for SV2A and SV2B.

  20. Synthesis, characterization, DNA binding and cleavage studies of mixed-ligand copper (II complexes

    Directory of Open Access Journals (Sweden)

    M. Sunita

    2017-05-01

    Full Text Available New two copper complexes of type [Cu(Bzimpy(LH2O]SO4 (where L = 2,2′ bipyridine (bpy, and ethylene diamine (en, Bzimpy = 2,6-bis(benzimidazole-2ylpyridine have been synthesized and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. Based on elemental and spectral studies six coordinated geometries were assigned to the two complexes. DNA-binding properties of these metal complexes were investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation methods. Experimental studies suggest that the complexes bind to DNA through intercalation. These complexes also promote the cleavage of plasmid pBR322, in the presence of H2O2.

  1. 4-Aminoquinoline-pyrimidine hybrids: synthesis, antimalarial activity, heme binding and docking studies.

    Science.gov (United States)

    Kumar, Deepak; Khan, Shabana I; Tekwani, Babu L; Ponnan, Prija; Rawat, Diwan S

    2015-01-07

    A series of novel 4-aminoquinoline-pyrimidine hybrids has been synthesized and evaluated for their antimalarial activity. Several compounds showed promising in vitro antimalarial activity against both CQ-sensitive and CQ-resistant strains with high selectivity index. All the compounds were found to be non-toxic to the mammalian cell lines. Selected compound 7g exhibited significant suppression of parasitemia in the in vivo assay. The heme binding studies were conducted to determine the mode of action of these hybrid molecules. These compounds form a stable 1:1 complex with hematin suggesting that heme may be one of the possible targets of these hybrids. The interaction of these conjugate hybrids was also investigated by the molecular docking studies in the binding site of PfDHFR. The pharmacokinetic property analysis of best active compounds was also studied using ADMET prediction. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  2. Molecular shape and binding force of Mycoplasma mobile's leg protein Gli349 revealed by an AFM study

    International Nuclear Information System (INIS)

    Lesoil, Charles; Nonaka, Takahiro; Sekiguchi, Hiroshi; Osada, Toshiya; Miyata, Makoto; Afrin, Rehana; Ikai, Atsushi

    2010-01-01

    Recent studies of the gliding bacteria Mycoplasma mobile have identified a family of proteins called the Gli family which was considered to be involved in this novel and yet fairly unknown motility system. The 349 kDa protein called Gli349 was successfully isolated and purified from the bacteria, and electron microscopy imaging and antibody experiments led to the hypothesis that it acts as the 'leg' of M. mobile, responsible for attachment to the substrate as well as for gliding motility. However, more precise evidence of the molecular shape and function of this protein was required to asses this theory any further. In this study, an atomic force microscope (AFM) was used both as an imaging and a force measurement device to provide new information about Gli349 and its role in gliding motility. AFM images of the protein were obtained revealing a complex structure with both rigid and flexible parts, consistent with previous electron micrographs of the protein. Single-molecular force spectroscopy experiments were also performed, revealing that Gli349 is able to specifically bind to sialyllactose molecules and withstand unbinding forces around 70 pN. These findings strongly support the idea that Gli349 is the 'leg' protein of M. mobile, responsible for binding and also most probably force generation during gliding motility.

  3. The impact of smoking and previous periodontal disease on peri-implant microbiota and health: a retrospective study up to 7-year follow-up.

    Science.gov (United States)

    Quaranta, Alessandro; Assenza, Bartolomeo; D'Isidoro, Orlando; Profili, Fabia; Polimeni, Antonella; Vozza, Iole

    2015-01-01

    To evaluate the impact of smoking and previous periodontal disease on peri-implant microbiota and health in medium to long-term maintained patients. A retrospective evaluation of partial edentulous patients restored with dental implants and enrolled in a regular supportive therapy was performed. Inclusion criteria were: medium to long-term periodontal and implant maintenance (at least 5 years), a minimum of 2 implants placed in each patient, absence of systemic diseases that may affect osseointegration. 30 implants in 15 patients were included in the study. Subjects were divided in smokers or non-smokers and between patients previously affected by periodontal disease and periodontally healthy. Peri-implant and periodontal parameters were assessed (PD,BoP, mPI). Microbiological samples were collected around implant and an adjacent tooth. Real- Time Polymerase Chain Reaction (RT-PCR) analysis was performed. In all the three groups no differences in bacterial counts between dental and implant sites were observed. Non smoker, healthy patients: healthy clinical parameters, significant counts of spirochetes in isolated patients. Non smokers with previous periodontal disease: occasional positive BoP values, significant high counts of pathogenic bacteria. Smokers with previous periodontal disease: clinical signs of inflammation including deep pockets and slight bone resorption, significant counts of pathogenic bacteria. Over a follow-up of 5 to 7 years, it is possible to state that the absence of smoking habit and previous periodontal disease positively influences the peri-implant microbiological and clinical conditions in partial edentulous patients restored with dental implants and enrolled in a strict regular supportive therapy.

  4. Characterisation of peptide microarrays for studying antibody-antigen binding using surface plasmon resonance imagery.

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    Claude Nogues

    Full Text Available BACKGROUND: Non-specific binding to biosensor surfaces is a major obstacle to quantitative analysis of selective retention of analytes at immobilized target molecules. Although a range of chemical antifouling monolayers has been developed to address this problem, many macromolecular interactions still remain refractory to analysis due to the prevalent high degree of non-specific binding. We describe how we use the dynamic process of the formation of self assembling monolayers and optimise physical and chemical properties thus reducing considerably non-specific binding and allowing analysis of specific binding of analytes to immobilized target molecules. METHODOLOGY/PRINCIPAL FINDINGS: We illustrate this approach by the production of specific protein arrays for the analysis of interactions between the 65kDa isoform of human glutamate decarboxylase (GAD65 and a human monoclonal antibody. Our data illustrate that we have effectively eliminated non-specific interactions with the surface containing the immobilised GAD65 molecules. The findings have several implications. First, this approach obviates the dubious process of background subtraction and gives access to more accurate kinetic and equilibrium values that are no longer contaminated by multiphase non-specific binding. Second, an enhanced signal to noise ratio increases not only the sensitivity but also confidence in the use of SPR to generate kinetic constants that may then be inserted into van't Hoff type analyses to provide comparative DeltaG, DeltaS and DeltaH values, making this an efficient, rapid and competitive alternative to ITC measurements used in drug and macromolecular-interaction mechanistic studies. Third, the accuracy of the measurements allows the application of more intricate interaction models than simple Langmuir monophasic binding. CONCLUSIONS: The detection and measurement of antibody binding by the type 1 diabetes autoantigen GAD65 represents an example of an antibody

  5. Binding studies of the antitumoral radiopharmaceutical 125I-Crotoxin to Ehrlich ascites tumor cells

    International Nuclear Information System (INIS)

    Silveira, Marina B.; Santos, Raquel G. dos; Dias, Consuelo L. Fortes; Cassali, Geovanni D.

    2009-01-01

    The development of tools for functional diagnostic imaging is mainly based on radiopharmaceuticals that specifically target membrane receptors. Crotoxin (Crtx), a polypeptide isolated from Crotalus durissus terrificus venom, has been shown to have an antitumoral activity and is a promising bioactive tracer for tumor detection. More specific radiopharmaceuticals are being studied to complement the techniques applied in the conventional medicine against breast cancer, the most frequent cause of death from malignant disease in women. Crtx's effect has been shown to be related with the overexpression of epidermal growth factor receptor (EGFR), present in high levels in 30 to 60% of breast tumor cells. Our objective was to evaluate Crtx as a tracer for cancer diagnosis, investigating its properties as an EGFR-targeting agent. Ehrlich ascites tumor cells (EAT cells) were used due to its origin and similar characteristics to breast tumor cells, specially the presence of EGFR. Crtx was labeled with 125I and binding experiments were performed. To evaluate the specific binding in vitro of Crtx, competition binding assay was carried out in the presence of increasing concentrations of non-labelled crotoxin and epidermal growth factor (EGF). Specific binding of 125I-Crtx to EAT cells was determined and the binding was considered saturable, with approximately 70% of specificity, high affinity (Kd = 19.7 nM) and IC50 = 1.6 x 10-11 M. Our results indicate that Crtx's interaction with EAT cells is partially related with EGFR and increases the biotechnological potential of Crtx as a template for radiopharmaceutical design for cancer diagnosis. (author)

  6. Binding studies of the antitumoral radiopharmaceutical 125I-Crotoxin to Ehrlich ascites tumor cells

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Marina B.; Santos, Raquel G. dos [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Dias, Consuelo L. Fortes [Fundacao Ezequiel Dias (FUNED), Belo Horizonte, MG (Brazil)], e-mail: consuelo@pq.cnpq.br; Cassali, Geovanni D. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Lab. de Patologia Comparada], e-mail: cassalig@icb.ufmg.br

    2009-07-01

    The development of tools for functional diagnostic imaging is mainly based on radiopharmaceuticals that specifically target membrane receptors. Crotoxin (Crtx), a polypeptide isolated from Crotalus durissus terrificus venom, has been shown to have an antitumoral activity and is a promising bioactive tracer for tumor detection. More specific radiopharmaceuticals are being studied to complement the techniques applied in the conventional medicine against breast cancer, the most frequent cause of death from malignant disease in women. Crtx's effect has been shown to be related with the overexpression of epidermal growth factor receptor (EGFR), present in high levels in 30 to 60% of breast tumor cells. Our objective was to evaluate Crtx as a tracer for cancer diagnosis, investigating its properties as an EGFR-targeting agent. Ehrlich ascites tumor cells (EAT cells) were used due to its origin and similar characteristics to breast tumor cells, specially the presence of EGFR. Crtx was labeled with 125I and binding experiments were performed. To evaluate the specific binding in vitro of Crtx, competition binding assay was carried out in the presence of increasing concentrations of non-labelled crotoxin and epidermal growth factor (EGF). Specific binding of 125I-Crtx to EAT cells was determined and the binding was considered saturable, with approximately 70% of specificity, high affinity (Kd = 19.7 nM) and IC50 = 1.6 x 10-11 M. Our results indicate that Crtx's interaction with EAT cells is partially related with EGFR and increases the biotechnological potential of Crtx as a template for radiopharmaceutical design for cancer diagnosis. (author)

  7. A comparative study of recombinant and native frutalin binding to human prostate tissues

    Directory of Open Access Journals (Sweden)

    Domingues Lucília

    2009-09-01

    Full Text Available Abstract Background Numerous studies indicate that cancer cells present an aberrant glycosylation pattern that can be detected by lectin histochemistry. Lectins have shown the ability to recognise these modifications in several carcinomas, namely in the prostate carcinoma, one of the most lethal diseases in man. Thus, the aim of this work was to investigate if the α-D-galactose-binding plant lectin frutalin is able to detect such changes in the referred carcinoma. Frutalin was obtained from different sources namely, its natural source (plant origin and a recombinant source (Pichia expression system. Finally, the results obtained with the two lectins were compared and their potential use as prostate tumour biomarkers was discussed. Results The binding of recombinant and native frutalin to specific glycoconjugates expressed in human prostate tissues was assessed by using an immuhistochemical technique. A total of 20 cases of prostate carcinoma and 25 cases of benign prostate hyperplasia were studied. Lectins bound directly to the tissues and anti-frutalin polyclonal antibody was used as the bridge to react with the complex biotinilated anti-rabbit IgG plus streptavidin-conjugated peroxidase. DAB was used as visual indicator to specifically localise the binding of the lectins to the tissues. Both lectins bound to the cells cytoplasm of the prostate carcinoma glands. The binding intensity of native frutalin was stronger in the neoplasic cells than in hyperplasic cells; however no significant statistical correlation could be found (P = 0.051. On the other hand, recombinant frutalin bound exclusively to the neoplasic cells and a significant positive statistical correlation was obtained (P Conclusion Native and recombinant frutalin yielded different binding responses in the prostate tissues due to their differences in carbohydrate-binding affinities. Also, this study shows that both lectins may be used as histochemical biomarkers for the prostate

  8. Synthesis, characterization, DNA-binding and cleavage studies of polypyridyl copper(II) complexes

    Science.gov (United States)

    Gubendran, Ammavasi; Rajesh, Jegathalaprathaban; Anitha, Kandasamy; Athappan, Periyakaruppan

    2014-10-01

    Six new mixed-ligand copper(II) complexes were synthesized namely [Cu(phen)2OAc]ClO4ṡH2O(1), [Cu(bpy)2OAc]ClO4ṡH2O(2), [Cu(o-ampacac)(phen)]ClO4(3), [Cu(o-ampbzac)(phen)]ClO4(4), [Cu(o-ampacac)(bpy)]ClO4(5), and [Cu(o-ampbzac)(bpy)]ClO4(6) (phen = 1,10-phenanthroline, bpy = 2, 2‧-bipyridine, o-ampacac = (Z)-4-(2-hydroxylamino)pent-3-ene-2-one,o-ampbzac = (Z)-4-(2-hydroxylamino)-4-phenylbut-3-ene-2-one)and characterized by UV-Vis, IR, EPR and cyclic voltammetry. Ligands were characterized by NMR spectra. Single crystal X-ray studies of the complex 1 shows Cu(II) ions are located in a highly distorted octahedral environment. Absorption spectral studies reveal that the complexes 1-6 exhibit hypochromicity during the interaction with DNA and binding constant values derived from spectral and electrochemical studies indicate that complexes 1, 2 and 3 bind strongly with DNA possibly by an intercalative mode. Electrochemical studies reveal that the complexes 1-4 prefer to bind with DNA in Cu(I) rather than Cu(II) form. The shift in the formal potentials E1/2 and CD spectral studies suggest groove or electrostatic binding mode for the complexes 4-6. Complex 1 can cleave supercoiled (SC) pUC18 DNA efficiently into nicked form II under photolytic conditions and into an open circular form (form II) and linear form (form III) in the presence of H2O2 at pH 8.0 and 37 °C, while the complex 2 does not cleave DNA under similar conditions.

  9. Mortality and cardiovascular risk associated with different insulin secretagogues compared with metformin in type 2 diabetes, with or without a previous myocardial infarction: a nationwide study

    DEFF Research Database (Denmark)

    Schramm, Tina Ken; Gislason, Gunnar Hilmar; Vaag, Allan

    2011-01-01

    Aims The impact of insulin secretagogues (ISs) on long-term major clinical outcomes in type 2 diabetes remains unclear. We examined mortality and cardiovascular risk associated with all available ISs compared with metformin in a nationwide study. Methods and results All Danish residents >20 years......, initiating single-agent ISs or metformin between 1997 and 2006 were followed for up to 9 years (median 3.3 years) by individual-level linkage of nationwide registers. All-cause mortality, cardiovascular mortality, and the composite of myocardial infarction (MI), stroke, and cardiovascular mortality...... associated with individual ISs were investigated in patients with or without previous MI by multivariable Cox proportional-hazard analyses including propensity analyses. A total of 107 806 subjects were included, of whom 9607 had previous MI. Compared with metformin, glimepiride (hazard ratios and 95...

  10. Interaction of Zn(II)bleomycin-A2 and Zn(II)peplomycin with a DNA hairpin containing the 5'-GT-3' binding site in comparison with the 5'-GC-3' binding site studied by NMR spectroscopy.

    Science.gov (United States)

    Follett, Shelby E; Ingersoll, Azure D; Murray, Sally A; Reilly, Teresa M; Lehmann, Teresa E

    2017-10-01

    Bleomycins are a group of glycopeptide antibiotics synthesized by Streptomyces verticillus that are widely used for the treatment of various neoplastic diseases. These antibiotics have the ability to chelate a metal center, mainly Fe(II), and cause site-specific DNA cleavage. Bleomycins are differentiated by their C-terminal regions. Although this antibiotic family is a successful course of treatment for some types of cancers, it is known to cause pulmonary fibrosis. Previous studies have identified that bleomycin-related pulmonary toxicity is linked to the C-terminal region of these drugs. This region has been shown to closely interact with DNA. We examined the binding of Zn(II)peplomycin and Zn(II)bleomycin-A 2 to a DNA hairpin of sequence 5'-CCAGTATTTTTACTGG-3', containing the binding site 5'-GT-3', and compared the results with those obtained from our studies of the same MBLMs bound to a DNA hairpin containing the binding site 5'-GC-3'. We provide evidence that the DNA base sequence has a strong impact in the final structure of the drug-target complex.

  11. β-lactoglobulin's conformational requirements for ligand binding at the calyx and the dimer interphase: a flexible docking study.

    Directory of Open Access Journals (Sweden)

    Lenin Domínguez-Ramírez

    Full Text Available β-lactoglobulin (BLG is an abundant milk protein relevant for industry and biotechnology, due significantly to its ability to bind a wide range of polar and apolar ligands. While hydrophobic ligand sites are known, sites for hydrophilic ligands such as the prevalent milk sugar, lactose, remain undetermined. Through the use of molecular docking we first, analyzed the known fatty acid binding sites in order to dissect their atomistic determinants and second, predicted the interaction sites for lactose with monomeric and dimeric BLG. We validated our approach against BLG structures co-crystallized with ligands and report a computational setup with a reduced number of flexible residues that is able to reproduce experimental results with high precision. Blind dockings with and without flexible side chains on BLG showed that: i 13 experimentally-determined ligands fit the calyx requiring minimal movement of up to 7 residues out of the 23 that constitute this binding site. ii Lactose does not bind the calyx despite conformational flexibility, but binds the dimer interface and an alternate Site C. iii Results point to a probable lactolation site in the BLG dimer interface, at K141, consistent with previous biochemical findings. In contrast, no accessible lysines are found near Site C. iv lactose forms hydrogen bonds with residues from both monomers stabilizing the dimer through a claw-like structure. Overall, these results improve our understanding of BLG's binding sites, importantly narrowing down the calyx residues that control ligand binding. Moreover, our results emphasize the importance of the dimer interface as an insufficiently explored, biologically relevant binding site of particular importance for hydrophilic ligands. Furthermore our analyses suggest that BLG is a robust scaffold for multiple ligand-binding, suitable for protein design, and advance our molecular understanding of its ligand sites to a point that allows manipulation to control

  12. Synthesis, characterization, anti-microbial, DNA binding and cleavage studies of Schiff base metal complexes

    Directory of Open Access Journals (Sweden)

    Poomalai Jayaseelan

    2016-09-01

    Full Text Available A novel Schiff base ligand has been prepared by the condensation between butanedione monoxime with 3,3′-diaminobenzidine. The ligand and metal complexes have been characterized by elemental analysis, UV, IR, 1H NMR, conductivity measurements, EPR and magnetic studies. The molar conductance studies of Cu(II, Ni(II, Co(II and Mn(II complexes showed non-electrolyte in nature. The ligand acts as dibasic with two N4-tetradentate sites and can coordinate with two metal ions to form binuclear complexes. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine nitrogen and oxyimino nitrogen atoms. The binuclear metal complexes exhibit octahedral arrangements. DNA binding properties of copper(II metal complex have been investigated by electronic absorption spectroscopy. Results suggest that the copper(II complex bind to DNA via an intercalation binding mode. The nucleolytic cleavage activities of the ligand and their complexes were assayed on CT-DNA using gel electrophoresis in the presence and absence of H2O2. The ligand showed increased nuclease activity when administered as copper complex and copper(II complex behave as efficient chemical nucleases with hydrogen peroxide activation. The anti-microbial activities and thermal studies have also been studied. In anti-microbial activity all complexes showed good anti-microbial activity higher than ligand against gram positive, gram negative bacteria and fungi.

  13. Insight of the Iron Binding and Transport in Dke1 - A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Hrvoje Brkić

    2015-12-01

    Full Text Available Acetylacetone dioxygenase from Acinetobacter johnsonii (Dke1 is a non-heme Fe2+ dependent enzyme which catalyzes the oxidative degradation of β-dicarbonyl compounds. It is a homotetramer with four active sites, each containing single metal ion. Since the active site is buried, knowledge on transport of the metal ion and reactants (products is essential for understanding the enzyme mechanism. The goal of this study was to assess the influence of several point mutations on the enzyme activity. The point mutations of hydrophilic amino acid residues (Tyr70, Arg80 and Glu98 that were shown to be important for metal binding and reactants stabilization were of the particular interest. Computational study enabled us to determine the preferred metal ion binding sites as well, as the pathways it utilizes to enter the enzyme active site. Besides, influence of the point mutations on the hydrogen bond network within enzyme was determined.

  14. Validation of tautomeric and protomeric binding modes by free energy calculations. A case study for the structure based optimization of d-amino acid oxidase inhibitors

    Science.gov (United States)

    Orgován, Zoltán; Ferenczy, György G.; Steinbrecher, Thomas; Szilágyi, Bence; Bajusz, Dávid; Keserű, György M.

    2018-02-01

    Optimization of fragment size d-amino acid oxidase (DAAO) inhibitors was investigated using a combination of computational and experimental methods. Retrospective free energy perturbation (FEP) calculations were performed for benzo[d]isoxazole derivatives, a series of known inhibitors with two potential binding modes derived from X-ray structures of other DAAO inhibitors. The good agreement between experimental and computed binding free energies in only one of the hypothesized binding modes strongly support this bioactive conformation. Then, a series of 1-H-indazol-3-ol derivatives formerly not described as DAAO inhibitors was investigated. Binding geometries could be reliably identified by structural similarity to benzo[d]isoxazole and other well characterized series and FEP calculations were performed for several tautomers of the deprotonated and protonated compounds since all these forms are potentially present owing to the experimental pKa values of representative compounds in the series. Deprotonated compounds are proposed to be the most important bound species owing to the significantly better agreement between their calculated and measured affinities compared to the protonated forms. FEP calculations were also used for the prediction of the affinities of compounds not previously tested as DAAO inhibitors and for a comparative structure-activity relationship study of the benzo[d]isoxazole and indazole series. Selected indazole derivatives were synthesized and their measured binding affinity towards DAAO was in good agreement with FEP predictions.

  15. The Role of Endogenous D2 Receptor Levels in Morphine Addiction: A Correlative Study of Morphine Place Conditioning and In Vivo [3H]-Raclopride Binding

    Energy Technology Data Exchange (ETDEWEB)

    Khan, N.; Gatley, S.

    2004-01-01

    Dopamine is a neurotransmitter that has a wide array of effects on an individual’s mental state. It is vital in the regulation of motor skills and in generating the effects of substance abuse. This study examined the dopamine D2 receptors found in the striatum of the brain. The impetus for investigating this receptor lies in the perception that it plays an influential role in drug addiction. It has been conjectured on the basis of human PET studies that possession of low levels of D2 receptors will heighten an individual’s susceptibility to drug addiction. However, an alternative explanation of low D2 receptor levels in drug dependent individuals is that these levels are a consequence of drug abuse. To understand this phenomenon, the present study employed the paradigm of conditioned place preference (CPP). In CPP, individuals of an out-bred mouse strain are observed to spend time in environments where they had previously been exposed to a drug that is abused by humans. The drug chosen for our studies was morphine because it has been previously shown to generate a robust place preference in mice and is a prototypic abused drug in humans. D2 receptor levels were quantified using an in vivo binding study involving [3H]raclopride, a radioactive compound that binds to D2 receptors. The results showed a significant place preference for morphine following the conditioning procedure. Additionally, data from the binding analysis agreed with previous studies that the striatum contains high levels of D2 receptors. However, there was no consistent relationship between the extent of morphine CPP and D2 receptor levels as revealed by [3H]-RAC binding. This finding does not support the hypothesis that low levels of D2 receptors predispose a mouse to easy morphine conditioning. Further experiments are required to determine the ability to generalize our findings to other species and other drugs of abuse.

  16. Functional studies of ssDNA binding ability of MarR family protein TcaR from Staphylococcus epidermidis.

    Directory of Open Access Journals (Sweden)

    Yu-Ming Chang

    Full Text Available The negative transcription regulator of the ica locus, TcaR, regulates proteins involved in the biosynthesis of poly-N-acetylglucosamine (PNAG. Absence of TcaR increases PNAG production and promotes biofilm formation in Staphylococci. Previously, the 3D structure of TcaR in its apo form and its complex structure with several antibiotics have been analyzed. However, the detailed mechanism of multiple antibiotic resistance regulator (MarR family proteins such as TcaR is unclear and only restricted on the binding ability of double-strand DNA (dsDNA. Here we show by electrophoretic mobility shift assay (EMSA, electron microscopy (EM, circular dichroism (CD, and Biacore analysis that TcaR can interact strongly with single-stranded DNA (ssDNA, thereby identifying a new role in MarR family proteins. Moreover, we show that TcaR preferentially binds 33-mer ssDNA over double-stranded DNA and inhibits viral ssDNA replication. In contrast, such ssDNA binding properties were not observed for other MarR family protein and TetR family protein, suggesting that the results from our studies are not an artifact due to simple charge interactions between TcaR and ssDNA. Overall, these results suggest a novel role for TcaR in regulation of DNA replication. We anticipate that the results of this work will extend our understanding of MarR family protein and broaden the development of new therapeutic strategies for Staphylococci.

  17. Binding studies of costunolide and dehydrocostuslactone with HSA by spectroscopy and atomic force microscopy

    International Nuclear Information System (INIS)

    Gao Wenhua; Li Nana; Chen Gaopan; Xu Yanping; Chen Yaowen; Hu Shunlin; Hu Zhide

    2011-01-01

    Human serum albumin (HSA), a major plasma protein and plasma-derived therapeutic, interacts with a wide variety of drugs and native plasma metabolites. In this study the interactions of costunolide (CE) and dehydrocostuslactone (DE) with HSA were investigated by molecule modeling, atomic force microscopy (AFM), and different optical techniques. In the mechanism discussion, it was proved that fluorescence quenching of HSA by both of the drugs is a result of the formation of drug-HSA complexes. Binding parameters for the reactions were determined according to the Stern-Volmer equation and static quenching. The results of thermodynamic parameters ΔG 0 , ΔH 0 , and ΔS 0 at different temperatures indicated that hydrogen bonding interactions play a major role in the drug-HSA associations process. The binding properties were further studied by quantitative analysis of CD, FTIR, and Raman spectra. Furthermore, AFM results showed that the dimension of HSA molecules became more swollen after binding with the drugs. - Highlights: → Interactions of costunolide and dehydrocostuslactone with HSA have been investigated for the first time. → Raman spectra were used to analyze the drug-HSA interactions. → Atomic force microscopy has been used to study the topography change of HSA by addition of the drugs. → These results are important for the drugs containing costunolide and dehydrocostuslactone distribution and metabolism.

  18. Design, synthesis and DNA-binding study of some novel morpholine linked thiazolidinone derivatives

    Science.gov (United States)

    War, Javeed Ahmad; Srivastava, Santosh Kumar; Srivastava, Savitri Devi

    2017-02-01

    The emergence of multiple drug resistance amongst bacterial strains resulted in many clinical drugs to be ineffective. Being vulnerable to bacterial infections any lack in the development of new antimicrobial drugs could pose a serious threat to public health. Here we report design and synthesis of a novel class of morpholine linked thiazolidinone hybrid molecules. The compounds were characterized by FT-IR, NMR and HRMS techniques. Susceptibility tests showed that most of the synthesized molecules were highly active against multiple bacterial strains. Compound 3f displayed MIC values which were better than the standard drug for most of the tested strains. DNA being a well defined target for many antimicrobial drugs was probed as possible target for these synthetic molecules. DNA-binding study of 3f with sm-DNA was probed through UV-vis absorption, fluorescence quenching, gel electrophoresis and molecular docking techniques. The studies revealed that compound 3f has strong affinity towards DNA and binds at the minor groove. The docking studies revealed that the compound 3f shows preferential binding towards A/T residues.

  19. The RNA binding site of S8 ribosomal protein of Escherichia coli: Selex and hydroxyl radical probing studies.

    Science.gov (United States)

    Moine, H; Cachia, C; Westhof, E; Ehresmann, B; Ehresmann, C

    1997-03-01

    The RNA binding site of ribosomal protein S8 of Escherichia coli is confined to a small region within the stem of a hairpin in 16S rRNA (nt 588-605/633-651), and thus represents a model system for understanding RNA/protein interaction rules. The S8 binding site on 16S rRNA was suspected to contain noncanonical features difficult to prove with classical genetical or biochemical means. We performed in vitro iterative selection of RNA aptamers that bind S8. For the different aptamers, the interactions with the protein were probed with hydroxyl radicals. Aptamers that were recognized according to the same structural rules as wild-type RNA, but with variations not found in nature, were identified. These aptamers revealed features in the S8 binding site that had been concealed during previous characterizations by the high base conservation throughout evolution. Our data demonstrate that the core structure of the S8 binding site is composed of three interdependent bases (nt 597/641/643), with an essential intervening adenine nucleotide (position 642). The other elements important for the binding site are a base pair (598/640) above the three interdependent bases and a bulged base at position 595, the identity of which is not important. Possible implications on the geometry of the S8 binding site are discussed with the help of a three-dimensional model.

  20. Risk for high depressive symptoms in diagnosed and previously undetected diabetes: 5-year follow-up results of the Heinz Nixdorf Recall study.

    Directory of Open Access Journals (Sweden)

    Andrea Icks

    Full Text Available OBJECTIVE: The objective of this study was to determine the risk for the development of high depressive symptoms in study participants with diagnosed and previously undetected diabetes mellitus compared to those without diabetes in a prospective population-based cohort study in Germany. METHODS: We estimated the 5-year cumulative incidence of high depressive symptoms in participants without high depressive symptoms at baseline (n = 3,633, 51.4% men, mean age (SD 59.1 (7.6 years, 7.0% diagnosed diabetes, 5.3% previously undetected diabetes from the population-based Heinz Nixdorf Recall study. Diabetes was assessed by self-report, medication, and blood glucose. High depressive symptoms were assessed using CES-D. We calculated odds ratios and their corresponding 95% confidence interval, using multiple logistic regression analyses. RESULT: Cumulative 5-year incidences (95% CI of high depressive symptoms in participants with diagnosed, undetected, and without diabetes were 7.1 (4.2-10.9, 4.1 (1.8-8.0, and 6.5 (5.6-7.4, respectively. The age-sex-adjusted OR for developing high depressive symptoms was 1.22 (0.74-2.03 in participants with diagnosed compared to those without diabetes, and 1.00 (0.59-1.68 after adjustment for BMI, physical activity, education, stroke, and myocardial infarction. The age-sex adjusted OR for developing high depressive symptoms in participants with previously undetected diabetes compared to those without diabetes was 0.72; 0.35-1.48; and fully adjusted 0.62; 0.30-1.30. CONCLUSION: We found no significant associations, maybe due to low power. However, our results are in line with a recent meta-analysis suggesting that risk of developing high depressive symptoms in patients with diagnosed diabetes may be moderately higher than in those without diabetes, and that comorbidity may explain in part this association. In participants with previously undetected diabetes, this first longitudinal study indicates that the risk is not

  1. Interaction of D-LSD with binding sites in brain: a study in vivo and in vitro

    International Nuclear Information System (INIS)

    Ebersole, B.L.J.

    1985-01-01

    The localization of [ 3 H]-d-lysergic acid diethylamide ([ 3 H]LSD) binding sites in the mouse brain was compared in vivo and in vitro. Radioautography of brain sections incubated with [ 3 H]LSD in vitro revealed substantial specific [ 3 H]LSD binding in cortical layers III-IV and areas CA1 and dentate gyrus in hippocampus. In contrast, in brain sections from animals that received [ 3 H]LSD in vivo, binding in hippocampus was scant and diffuse, although the pattern of labeling in cortex was similar to that seen in vitro. The low specific binding in hippocampus relative to cortex was confirmed by homogenate filtration studies of brain areas from mice that received injections of [ 3 H]LSD. Time-course studies established that peak specific binding at ten minutes was the same in cortex and hippocampus. At all times, binding in hippocampus was about one-third of that in cortex; in contrast, the concentration of free [ 3 H]LSD did not vary between regions. This finding was unexpected, because binding studies in vitro in membrane preparations indicated that the density and affinity of [ 3 H]LSD binding sites were similar in both brain regions. Saturation binding studies in vivo showed that the lower amount of [ 3 H]LSD binding in hippocampus was attributable to a lower density of sites labeled by [ 3 H]LSD. The pharmacological identify of [ 3 H]LSD binding sites in vivo may be relevant to the hallucinogenic properties of LSD and of other related hallucinogens

  2. A histochemical study of the microglial cells in the brain of Salamandra salamandra by lectin binding.

    Science.gov (United States)

    Franceschini, V; Ciani, F

    1992-01-01

    Seven biotinylated lectins were utilized as histochemical markers for the study of microglial cells in the brain of Salamandra salamandra. It has been demonstrated that SBA, BSA-I, BSA-I-B4 and RCA120 label the microglial cells and, on the basis of the binding selectivity of the single lectins for specific carbohydrates, it was found that alpha-galactosyl residues are present in high density on the microglial membrane of S. salamandra. The reaction was localized not only to the ramified microglial cells, but also to other round cells without extensions, interpreted as ameboid microglial cells. The results show that lectin binding is a reliable molecular probe for identifying microglial cells in urodels.

  3. Synthesis of 4,4-ditritio-(+)-nicotine: comparative binding and distribution studies with natural enantiomer

    Energy Technology Data Exchange (ETDEWEB)

    Vincek, W.C.; Martin, B.R.; Aceto, M.D.; Tripathi, H.L.; May, E.L.; Harris, L.S.

    1981-11-01

    The preparation of 4,4-ditritio-(+)-nicotine (Vb) (specific activity 10.3 Ci/mmole)from (+)-nicotine (Ib) via (-) 4,4-dibromocotinine (IIIb) is described. Although Ib is 10-30 times less potent than (-)-nicotine (Ia) in the CNS, its binding affinity for the crude mitochondrial or nuclear fraction of whole rat brain is only three times less than that of Ia. However, distribution studies showed that the maximum brain levels of (-)-(3H) nicotine are nearly twice those of (+)-(3H)-nicotine following administration of a 2-micrograms/kg dose. Binding affinity and disposition of the stereoisomers account for a portion of the pharmacological stereospecificity of nicotine.

  4. EO-199, a specific antagonist of antiarrhythmic drugs: Assessment by binding experiments and in vivo studies

    Energy Technology Data Exchange (ETDEWEB)

    Oppenheimer, E.; Harel, G.; Lipinsky, D.; Sarne, Y. (Tel-Aviv Univ. (Israel))

    1991-01-01

    EO-199, a demethylated analog of the novel class I antiarrhythmic drug EO-122 was found to antagonize the antiarrhythmic activity of EO-122 and that of procainamide (Class I{sub A}). EO-199 did not block significantly the activity of a class I{sub B} antiarrhythmic agent, lidocaine. EO-199 also displaced the specific binding of ({sup 3}H)EO-122 to rate heart membranes similarly to procainamide whereas lidocaine did not. The correlation between binding experiments and pharmacological effects points to a possible subclassification of these drugs; the two chemical analogs EO-199 and EO-122, as well as procainamide (I{sub A}) but not lidocaine (I{sub B}), compete at the same site or the same state of the sodium channel. The availability of a specific antagonist might be useful for studying the mechanism of action of antiarrhythmic drugs as well as an antidote in cases of antiarrhythmics overdose intoxication.

  5. Study on the binding mode of zinc(II) protoporphyrin and ctDNA in water

    Science.gov (United States)

    Tong, Ai-jun; Tong, Chun-yuan; Yang, Qing-yi

    2003-11-01

    Spectroscopic property of a commercially available luminescent reagent Zinc(II) protoporphyrin (ZnPP) was studied. Dissociation constants of the two protons on the peripheral groups of porphyrin ring of ZnPP were determined as p Ka1=6.31, p Ka2=9.37. Binding evidence of ZnPP with ctDNA was found by the phosphorescence intensity change on a filter paper around pH 6.5-9.3 with the association constant being 9.1×10 3 dm 3/mol. A novel binding mode for ZnPP and calf thymus DNA (ctDNA) suggested that the monomer ZnPP which has no axial coordination, slips into the groove of DNA and interacts with the bases of polynucleotide by zinc coordination and hydrogen bonding between H atom on carboxyl group of ZnPP and O atom on the bases.

  6. Synthesis of 4,4-ditritio-(+)-nicotine: comparative binding and distribution studies with natural enantiomer

    International Nuclear Information System (INIS)

    Vincek, W.C.; Martin, B.R.; Aceto, M.D.; Tripathi, H.L.; May, E.L.; Harris, L.S.

    1981-01-01

    The preparation of 4,4-ditritio-(+)-nicotine (Vb) (specific activity 10.3 Ci/mmole)from (+)-nicotine (Ib) via (-) 4,4-dibromocotinine (IIIb) is described. Although Ib is 10-30 times less potent than (-)-nicotine (Ia) in the CNS, its binding affinity for the crude mitochondrial or nuclear fraction of whole rat brain is only three times less than that of Ia. However, distribution studies showed that the maximum brain levels of (-)-[3H] nicotine are nearly twice those of (+)-[3H]-nicotine following administration of a 2-micrograms/kg dose. Binding affinity and disposition of the stereoisomers account for a portion of the pharmacological stereospecificity of nicotine

  7. Comparison of time until elective intestinal resection regarding previous anti-tumor necrosis factor exposure: a Brazilian study on patients with Crohn's disease

    Directory of Open Access Journals (Sweden)

    Paulo Gustavo Kotze

    2018-01-01

    Full Text Available Background/Aims: The use of anti-tumor necrosis factor (anti-TNF agents seems to reduce surgical rates and delay surgical procedures in prospective trials and population-based studies in the management of Crohn's disease (CD. This study aimed to identify whether preoperative anti-TNF agents influence the time from diagnosis to surgery. Methods: An observational retrospective cohort study was conducted on patients with CD submitted to intestinal resections due to complications or medical therapy failure in a period of 7 years. The patients were allocated into 2 groups according to their previous exposure to anti-TNF agents in the preoperative period. Epidemiological aspects regarding age at diagnosis, smoking, perianal disease, and preoperative conventional therapy were considered. A Kaplan-Meier survival analysis was used to outline possible differences between the groups regarding the time to surgery. Results: A total of 123 patients were included (71 and 52 with and without previous exposure to biologics, respectively. The overall time to surgery was 108±6.9 months (maximum, 276 months. The survival estimation revealed no difference in the mean time to intestinal resection between the groups (99.78±10.62 months in the patients without and 114.01±9.07 months in those with previous anti-TNF use (log-rank P=0.35. There was no significant difference in the time to surgery regarding perianal CD (P=0.49, smoking (P=0.63, preoperative azathioprine (P=0.073 and steroid use (P=0.58. Conclusions: The time from diagnosis to surgery was not influenced by the preoperative use of anti-TNF therapy in this cohort of patients.

  8. GPR17: Molecular modeling and dynamics studies of the 3-D structure and purinergic ligand binding features in comparison with P2Y receptors

    Directory of Open Access Journals (Sweden)

    Ranghino Graziella

    2008-06-01

    Full Text Available Abstract Background GPR17 is a G-protein-coupled receptor located at intermediate phylogenetic position between two distinct receptor families: the P2Y and CysLT receptors for extracellular nucleotides and cysteinyl-LTs, respectively. We previously showed that GPR17 can indeed respond to both classes of endogenous ligands and to synthetic compounds active at the above receptor families, thus representing the first fully characterized non-peptide "hybrid" GPCR. In a rat brain focal ischemia model, the selective in vivo knock down of GPR17 by anti-sense technology or P2Y/CysLT antagonists reduced progression of ischemic damage, thus highlighting GPR17 as a novel therapeutic target for stroke. Elucidation of the structure of GPR17 and of ligand binding mechanisms are the necessary steps to obtain selective and potent drugs for this new potential target. On this basis, a 3-D molecular model of GPR17 embedded in a solvated phospholipid bilayer and refined by molecular dynamics simulations has been the first aim of this study. To explore the binding mode of the "purinergic" component of the receptor, the endogenous agonist UDP and two P2Y receptor antagonists demonstrated to be active on GPR17 (MRS2179 and cangrelor were then modeled on the receptor. Results Molecular dynamics simulations suggest that GPR17 nucleotide binding pocket is similar to that described for the other P2Y receptors, although only one of the three basic residues that have been typically involved in ligand recognition is conserved (Arg255. The binding pocket is enclosed between the helical bundle and covered at the top by EL2. Driving interactions are H-bonds and salt bridges between the 6.55 and 6.52 residues and the phosphate moieties of the ligands. An "accessory" binding site in a region formed by the EL2, EL3 and the Nt was also found. Conclusion Nucleotide binding to GPR17 occurs on the same receptor regions identified for already known P2Y receptors. Agonist

  9. Studies of the binding mode of TXNHCH2COOH with calf thymus DNA by spectroscopic methods

    Science.gov (United States)

    Ataci, Nese; Arsu, Nergis

    2016-12-01

    In this study, a thioxanthone derivative named 2-(9-oxo-9H-thioxanthen-2ylamino) acetic acid (TX-NHCH2COOH) was used to investigate small molecule and DNA binding interactions. Absorption and fluorescence emission spectroscopy were used and melting studies were used to explain the binding mode of TXNHCH2COOH-DNA. Intrinsic binding constant Kb TXNHCH2COOH was found 6 × 105 M- 1from UV-Vis absorption spectroscopy. Fluorescence emmision intensity increased by adding ct-DNA to the TXNHCH2COOH and KI quenching experiments resulted with low Ksv value. Additionally, 3.7 °C increase for Tm was observed. The observed quenching of EB and ct-DNA complex and increase viscosity values of ct-DNA by addition of TXNHCH2COOH was determined. All those results indicate that TXNHCH2COOH can intercalate into DNA base pairs. Fluorescence microscopy helped to display imaging of the TXNHCH2COOH-DNA solution.

  10. Theoretical study of the binding nature of glassy carbon with nickel(II) phthalocyanine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cortez, Luis [Laboratorio de Quimica Teorica, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile); Berrios, Cristhian [Laboratorio de Electrocatalisis, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile); Yanez, Mauricio [Laboratorio de Recursos Renovables, Centro de Biotecnologia, Universidad de Concepcion, Casilla-160 C, Concepcion (Chile); Cardenas-Jiron, Gloria I., E-mail: gloria.cardenas@usach.cl [Laboratorio de Quimica Teorica, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile)

    2009-11-26

    A theoretical study at the semiempirical RHF/PM3(tm) level (tm: transition metal) of the binding nature between a glassy carbon (GC) cluster and a nickel(II) complex (nickel(II) phthalocyanine NiPc, nickel(II) tetrasulphophthalocyanine NiTSPc) was performed. Three types of interactions for GC...NiPc (NiTSPc) were studied: (a) through an oxo (O) bridge, (b) through an hydroxo (OH) bridge, and (c) non-bridge. One layer (NiPc, NiTSPc) and two layers (NiPc...NiPc) of complex were considered. The binding energy calculated showed that in both cases NiPc and NiTSPc, the oxo structures are more stable than the hydroxo ones, and than the non-bridge systems. Charge analysis (NAO) predicted that GC gained more electrons in an oxo structure than in the analogues hydroxo. The theoretical results showed an agreement with the experimental data available, an oxo binding between GC and a nickel complex (NiPc, NiTSPc) in aqueous alkaline solutions is formed.

  11. DNA binding and cleavage studies of copper(II) complexes with 2'-deoxyadenosine modified histidine moiety.

    Science.gov (United States)

    Borowska, Justyna; Sierant, Malgorzata; Sochacka, Elzbieta; Sanna, Daniele; Lodyga-Chruscinska, Elzbieta

    2015-09-01

    This work is focused on the study of DNA binding and cleavage properties of 2'-deoxyadenosines modified with ester/amide of histidine (his(6)dA ester, his(6)dA amide) and their copper(II) complexes. To determine the coordination mode of the complex species potentiometric and spectroscopic (UV-visible, CD, EPR) studies have been performed. The analysis of electronic absorption and fluorescence spectra has been used to find the nature of the interactions between the compounds and calf thymus DNA (CT-DNA). There is significant influence of the -NH2 and -OCH3 groups on binding of the ligands or the complexes to DNA. Only amide derivative and its complex reveal intercalative ability. In the case of his(6)dA ester and Cu(II)-his(6)dA ester the main interactions can be groove binding. DNA cleavage activities of the compounds have been examined by gel electrophoresis. The copper complexes have promoted the cleavage of plasmid DNA, but none of the ligands exhibited any chemical nuclease activity. The application of different scavengers of reactive oxygen species provided a conclusion that DNA cleavage caused by copper complexes might occur via hydrolytic pathway.

  12. Theoretical study of the binding nature of glassy carbon with nickel(II) phthalocyanine complexes

    International Nuclear Information System (INIS)

    Cortez, Luis; Berrios, Cristhian; Yanez, Mauricio; Cardenas-Jiron, Gloria I.

    2009-01-01

    A theoretical study at the semiempirical RHF/PM3(tm) level (tm: transition metal) of the binding nature between a glassy carbon (GC) cluster and a nickel(II) complex (nickel(II) phthalocyanine NiPc, nickel(II) tetrasulphophthalocyanine NiTSPc) was performed. Three types of interactions for GC...NiPc (NiTSPc) were studied: (a) through an oxo (O) bridge, (b) through an hydroxo (OH) bridge, and (c) non-bridge. One layer (NiPc, NiTSPc) and two layers (NiPc...NiPc) of complex were considered. The binding energy calculated showed that in both cases NiPc and NiTSPc, the oxo structures are more stable than the hydroxo ones, and than the non-bridge systems. Charge analysis (NAO) predicted that GC gained more electrons in an oxo structure than in the analogues hydroxo. The theoretical results showed an agreement with the experimental data available, an oxo binding between GC and a nickel complex (NiPc, NiTSPc) in aqueous alkaline solutions is formed.

  13. Binding of carbendazim to bovine serum albumin: Insights from experimental and molecular modeling studies

    Science.gov (United States)

    Li, Jinhua; Zhang, Yulei; Hu, Lin; Kong, Yaling; Jin, Changqing; Xi, Zengzhe

    2017-07-01

    Carbendazim (CBZ) is a widely used benzimidazole fungicide in agriculture to control a wide range of fruit and vegetable pathogens, which may lead to potential health hazards. To evaluate the potential toxicity of CBZ, the binding mechanism of bovine serum albumin (BSA) with CBZ was investigated by the fluorescence quenching technology, UV absorbance spectra, circular dichroism (CD), and molecular modeling. The fluorescence titration and UV absorbance spectra revealed that the fluorescence quenching mechanism of BSA by CBZ was a combined quenching process. In addition, the studies of CD spectra suggested that the binding of CBZ to BSA changed the secondary structure of protein. Furthermore, the thermodynamic functions of enthalpy change (ΔH0) and entropy change (ΔS0) for the reaction were calculated to be 24.87 kJ mol-1 and 162.95 J mol-1 K-1 according to Van't Hoff equation. These data suggested that hydrophobic interaction play a major role in the binding of CBZ to BSA, which was in good agreement with the result of molecular modeling study.

  14. Synthesis, structure, DNA/BSA binding and antibacterial studies of NNO tridentate Schiff base metal complexes

    Science.gov (United States)

    Sakthi, Marimuthu; Ramu, Andy

    2017-12-01

    A new salicylaldehyde derived 2,4-diiodo-6-((2-phenylaminoethylimino)methyl)phenol Schiff base(L) and its transition metal complexes of the type MLCl where, M = Cu(II), Ni(II), Co(II), Mn(II) and Zn(II) have been synthesized. The coordination mode of Schiff base holding NNO donor atoms with metal ions was well investigated by elemental analysis, ESI-mass as well as IR, UV-vis, CV and NMR spectral studies. The binding efficiency and mode of these complexes with biological macromolecules viz., herring sperm DNA (HS- DNA) and bovine serum albumin (BSA) have been explored through various spectroscopic techniques. The characteristic changes in absorption, emission and, circular dichroism spectra of the complexes with DNA indicate the noticeable interaction between them. From the all spectral information complexes could interact with DNA via non-intercalation mode of binding. The hyperchromisim in absorption band and hypochromisim in emission intensity of BSA with different complex concentrations shown significant information, and the binding affinity value has been predicted from Stern-Volmer plots. Further, all the complexes could cleave the circular plasmid pUC19 DNA efficiently by using an activator H2O2. The ligand and all metal(II) complexes showed good antibacterial activities. The molecular docking studies of the complexes with DNA were performed in order to make a comparison and conclusion with spectral technic results.

  15. Natural alkaloid Luotonin A and its affixed acceptor molecules: Serum albumin binding studies.

    Science.gov (United States)

    Kesavan, Mookkandi Palsamy; Kumar, Gujuluva Gangatharan Vinoth; Anitha, Kandasamy; Ravi, Lokesh; Raja, Jeyaraj Dhaveethu; Rajagopal, Gurusamy; Rajesh, Jegathalaprathaban

    2017-08-01

    Effective interaction of natural alkaloid Luotonin A (L) and its affixed acceptor molecules 1 and 2 with donor molecule as Bovine serum albumin (BSA) at various pH (4.0, 7.4 and 10.0) medium have been demonstrated using various conventional spectroscopic techniques. These analyses provide some valuable features on the interaction between BSA and acceptor molecules (L, 1 and 2). From the absorption and fluorescence spectral titration studies, the formation of ground-state complexes between the acceptor molecules (L, 1 and 2) and the BSA have been confirmed. The results of the afore titrations analysis reveal that, the strong binding of receptor 1 with BSA (K app 5.68×10 4 M -1 ; K SV 1.86×10 6 Lmol -1 ; K a 6.42×10 5 Lmol -1 ; K ass 8.09×10 6 M -1 ; ΔG -33.35kJ/mol) at physiological pH medium (7.4) than other receptor molecules 2 and L. The Förster resonance energy transfer (FRET) efficiency between the tryptophan (Trp) residues of BSA and acceptor molecules L, 1 and 2 during the interaction, are 28.85, 85.24 and 53.25 % respectively. The superior binding efficacy of acceptor 1 at physiological pH condition has been further confirmed by FT-IR and Raman spectral analysis methods. Moreover, theoretical docking studies of acceptors L, 1 and 2 towards HSA have been demonstrated to differentiate their binding behaviours. It reveals that, acceptor 1 has the strongest binding ability with HSA through two hydrogen bonding and the Atomic contact energy (ACE) value of -483.96kcal/mol. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Isothermal titration calorimetric and computational studies on the binding of chitooligosaccharides to pumpkin (Cucurbita maxima) phloem exudate lectin.

    Science.gov (United States)

    Narahari, Akkaladevi; Singla, Hitesh; Nareddy, Pavan Kumar; Bulusu, Gopalakrishnan; Surolia, Avadhesha; Swamy, Musti J

    2011-04-14

    The interaction of chitooligosaccharides [(GlcNAc)(2-6)] with pumpkin phloem exudate lectin (PPL) was investigated by isothermal titration calorimetry and computational methods. The dimeric PPL binds to (GlcNAc)(3-5) with binding constants of 1.26-1.53 × 10(5) M(-1) at 25 °C, whereas chitobiose exhibits approximately 66-fold lower affinity. Interestingly, chitohexaose shows nearly 40-fold higher affinity than chitopentaose with a binding constant of 6.16 × 10(6) M(-1). The binding stoichiometry decreases with an increase in the oligosaccharide size from 2.26 for chitobiose to 1.08 for chitohexaose. The binding reaction was essentially enthalpy driven with negative entropic contribution, suggesting that hydrogen bonds and van der Waals' interactions are the main factors that stabilize PPL-saccharide association. The three-dimensional structure of PPL was predicted by homology modeling, and binding of chitooligosaccharides was investigated by molecular docking and molecular dynamics simulations, which showed that the protein binding pocket can accommodate up to three GlcNAc residues, whereas additional residues in chitotetraose and chitopentaose did not exhibit any interactions with the binding pocket. Docking studies with chitohexaose indicated that the two triose units of the molecule could interact with different protein binding sites, suggesting formation of higher order complexes by the higher oligomers of GlcNAc by their simultaneous interaction with two protein molecules.

  17. Food intake during the previous 24 h as a percentage of usual intake: a marker of hypoxia in infants with bronchiolitis: an observational, prospective, multicenter study

    Directory of Open Access Journals (Sweden)

    Corrard François

    2013-01-01

    Full Text Available Abstract Background Hypoxia associated with bronchiolitis is not always easy to assess on clinical grounds alone. The aim of this study was to determine the value of food intake during the previous 24 hours (bottle and spoon feeding, as a percentage of usual intake (24h FI, as a marker of hypoxia, and to compare its diagnostic value with that of usual clinical signs. Methods In this observational, prospective, multicenter study, 18 community pediatricians, enrolled 171 infants, aged from 0 to 6 months, with bronchiolitis (rhinorrhea + dyspnea + cough + expiratory sounds. Infants with risk factors (history of prematurity, chronic heart or lung disorders, breast-fed infants, and infants having previously been treated for bronchial disorders were excluded. The 24h FI, subcostal, intercostal, supracostal retractions, nasal flaring, respiratory rate, pauses, cyanosis, rectal temperature and respiratory syncytial virus test results were noted. The highest stable value of transcutaneous oxygen saturation (SpO2 was recorded. Hypoxia was noted if SpO2 was below 95% and verified. Results 24h FI ≥ 50% was associated with a 96% likelihood of SpO2 ≥ 95% [95% CI, 91–99]. In univariate analysis, 24h FI  Conclusion In practice, the measure of 24 h FI may be useful in identifying hypoxia and deserves further study.

  18. Stability, protein binding and clearance studies of [99mTc]DTPA. Evaluation of a commercially available dry-kit

    DEFF Research Database (Denmark)

    Rehling, M

    1988-01-01

    the quality of a commercial [99mTc]DTPA preparation (C.I.S., France) with reference to stability, protein binding and accuracy of the determined plasma clearance values as a measure of GFR. The stability of the preparations was studied by thin-layer chromatography, the in vitro protein binding by Sephadex...

  19. Spectroscopic studies on the binding interaction of phenothiazinium dyes toluidine blue O, azure A and azure B to DNA

    Science.gov (United States)

    Paul, Puja; Suresh Kumar, Gopinatha

    2013-04-01

    In this study a detailed characterization of the binding aspects of three phenothiazinium dyes, toluidine blue O (TBO), azure A and azure B with herring testes DNA is presented employing spectroscopic techniques. The absorbance and fluorescence properties of these dyes have been remarkably modified upon binding with DNA and the interaction is manifested through noncooperative binding as revealed form non-linear Scatchard plots with negative slopes at all binding ratios. The binding clearly revealed the high preference of TBO to DNA followed by the other two dyes azure A and azure B. The affinity of TBO was higher by about two times than that of the azures. From the series of studies using absorption, steady-state emission, the effect of ferrocyanide ion-induced steady-state fluorescence quenching, fluorescence polarization anisotropy, circular dichroism, the mode of binding of these dyes to the DNA double helix has been substantiated to be principally intercalative in nature. The stoichiometry of the association of these dyes to DNA was determined by the continuous variation analysis of Job from fluorescence data. The conformational aspects of the interaction was delineated from circular dichroism studies wherein higher perturbation was observed with TBO. Hydrodynamic study using viscosity measurements of linear rod like DNA confirmed that the binding was intercalative and strongest for TBO and weaker for azure A and azure B. The utility of the present work lies in exploring the potential binding applicability of these dyes to DNA for their development as effective therapeutic agents.

  20. Reference tissue modeling with parameter coupling: application to a study of SERT binding in HIV

    Energy Technology Data Exchange (ETDEWEB)

    Endres, Christopher J; Pomper, Martin G [Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21231 (United States); Hammoud, Dima A, E-mail: endres@jhmi.edu [Radiology and Imaging Sciences, National Institutes of Health/Clinical Center, Bethesda, MD (United States)

    2011-04-21

    When applicable, it is generally preferred to evaluate positron emission tomography (PET) studies using a reference tissue-based approach as that avoids the need for invasive arterial blood sampling. However, most reference tissue methods have been shown to have a bias that is dependent on the level of tracer binding, and the variability of parameter estimates may be substantially affected by noise level. In a study of serotonin transporter (SERT) binding in HIV dementia, it was determined that applying parameter coupling to the simplified reference tissue model (SRTM) reduced the variability of parameter estimates and yielded the strongest between-group significant differences in SERT binding. The use of parameter coupling makes the application of SRTM more consistent with conventional blood input models and reduces the total number of fitted parameters, thus should yield more robust parameter estimates. Here, we provide a detailed evaluation of the application of parameter constraint and parameter coupling to [{sup 11}C]DASB PET studies. Five quantitative methods, including three methods that constrain the reference tissue clearance (k{sup r}{sub 2}) to a common value across regions were applied to the clinical and simulated data to compare measurement of the tracer binding potential (BP{sub ND}). Compared with standard SRTM, either coupling of k{sup r}{sub 2} across regions or constraining k{sup r}{sub 2} to a first-pass estimate improved the sensitivity of SRTM to measuring a significant difference in BP{sub ND} between patients and controls. Parameter coupling was particularly effective in reducing the variance of parameter estimates, which was less than 50% of the variance obtained with standard SRTM. A linear approach was also improved when constraining k{sup r}{sub 2} to a first-pass estimate, although the SRTM-based methods yielded stronger significant differences when applied to the clinical study. This work shows that parameter coupling reduces the

  1. Accuracy of preoperative real-time dynamic transvaginal ultrasound sliding sign in prediction of pelvic adhesions in women with previous abdominopelvic surgery: prospective, multicenter, double-blind study.

    Science.gov (United States)

    Ayachi, A; Bouchahda, R; Derouich, S; Mkaouer, L; Kehila, M; Abouda, H; Channoufi, B; Bouyahia, M; Braham, M; Zhioua, F; Bouchahda, H; Mourali, M

    2018-02-01

    To investigate the role of the transvaginal sonographic (TVS) sliding sign in predicting pelvic adhesions in women with previous abdominopelvic surgery. This was a multicenter, prospective, interventional, double-blind study of patients with a history of abdominopelvic surgery who were undergoing laparoscopy or laparotomy during the 6-month period from March to August 2016 in one of three academic obstetrics and gynecology departments. Prior to surgery, patients were examined by TVS to assess the vesicouterine pouch, uterus, ovaries and pouch of Douglas, using the TVS pelvic sliding sign. Ultrasound findings and medical and surgical data were recorded. We assessed the accuracy of the preoperative TVS sliding sign in the prediction of pelvic adhesions overall and in each compartment separately. During the study period, complete TVS sliding sign and laparoscopic or laparotomic data were available for 107 women. Their mean age was 44.0 (95% CI, 41.6-46.4; range, 20-79) years. Their mean parity was 2.0 (95% CI, 1.7-2.3; range, 0-9) and the mean number of previous abdominal surgical procedures per patient was 1.3 (95% CI, 1.2-1.5; range, 1-4). Adhesions were noted in 27/107 (25.2%) patients. The TVS sliding sign had a sensitivity of 96.3% and specificity of 92.6% in predicting pelvic adhesions. There was a significant relationship between adhesions in each compartment and the TVS sliding sign (P sign is an effective means to detect preoperatively pelvic adhesions in patients with previous abdominopelvic surgery. Use of such a non-invasive and well-tolerated technique could help in the planning of laparoscopy or laparotomy and counseling of these patients. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

  2. (/sup 3/H)nitrobenzylthioinosine binding as a probe for the study of adenosine uptake sites in brain

    Energy Technology Data Exchange (ETDEWEB)

    Marangos, P.J.; Patel, J.; Clark-Rosenberg, R.; Martino, A.M.

    1982-07-01

    The binding of the potent adenosine uptake inhibitor (/sup 3/H)nitrobenzylthioinosine ((/sup 3/H)NBI) to brain membrane fractions was investigated. Reversible, saturable, specific, high-affinity binding was demonstrated in both rat and human brain. The KD in both was 0.15 nM with Bmax values of 140-200 fmol/mg protein. Linear Scatchard plots were routinely obtained, indicating a homogeneous population of binding sites in brain. The highest density of binding sites was found in the caudate and hypothalamus in both species. The binding site was heat labile and trypsin sensitive. Binding was also decreased by incubation of the membranes in 0.05% Triton X-100 and by treatment with dithiothreitol and iodoacetamide. Of the numerous salt and metal ions tested, only copper and zinc had significant effects on (/sup 3/H)NBI binding. The inhibitory potencies of copper and zinc were IC50 . 160 microM and 6 mM, respectively. Subcellular distribution studies revealed a high percentage of the (/sup 3/H)NBI binding sites on synaptosomes, indicating that these sites were present in the synaptic region. A study of the tissue distribution of the (/sup 3/H)NBI sites revealed very high densities of binding in erythrocyte, lung, and testis, with much lower binding densities in brain, kidney, liver, muscle, and heart. The binding affinity in the former group was approximately 1.5 nM, whereas that in the latter group was 0.15 nM, suggesting two types of binding sites. The pharmacologic profile of (/sup 3/H)NBI binding was consistent with its function as the adenosine transport site, distinct from the adenosine receptor, since thiopurines were very potent inhibitors of binding whereas adenosine receptor ligands, such as cyclohexyladenosine and 2-chloroadenosine, were three to four orders of magnitude less potent. (/sup 3/H)NBI binding in brain should provide a useful probe for the study of adenosine transport in the brain.

  3. The contribution of previous lameness events and body condition score to the occurrence of lameness in dairy herds: A study of 2 herds.

    Science.gov (United States)

    Randall, L V; Green, M J; Green, L E; Chagunda, M G G; Mason, C; Archer, S C; Huxley, J N

    2018-02-01

    It has been demonstrated that low body condition and previous occurrence of lameness increase the risk of future lameness in dairy cows. To date the population attributable fraction (PAF), which provides an estimate of the contribution that a risk factor makes toward the total number of disease events in a population, has not been explored for lameness using longitudinal data with repeated measures. Estimation of PAF helps to identify control measures that could lead to the largest improvements on-farm. The aim of this study was to use longitudinal data to evaluate the proportion of lameness that could be avoided in 2 separate herds (2 populations) through (1) reduced recurrence of previous lameness events, (2) and moving body condition score (BCS) into more optimal ranges. Data were obtained from 2 UK dairy herds: herd A, a 200-cow herd with 8 yr of data from a total of 724 cows where lameness events were based on weekly locomotion scores (LS; 1 to 5 scale), and herd B, a 600-cow herd with data recorded over 44 mo from a total of 1,040 cows where treatment of clinical cases was used to identify lameness events. The PAF for categories of BCS were estimated using a closed equation appropriate for multiple exposure categories. Simulation models were used to explore theoretical scenarios to reflect changes in BCS and recurrence of previous lameness events in each herd. For herd A, 21.5% of the total risk periods (cow-weeks) contained a lameness event (LS 3, 4, or 5), 96% of which were repeat events and 19% were recorded with BCS events were based on 2 consecutive weeks of LS 4 or 5, 4% of risk periods were recorded as lame, of which 89.5% were repeat events. For herd B, 16.3% of the total risk periods (consecutive 30 d) contained a lameness event (72.6% were repeat events) and 20% were recorded with BCS ≤2 (0 to 120 d previously). The median PAF for all previous lameness was between 79 and 83% in the 2 herds. Between 9 and 21% of lameness events could be attributed

  4. Study on dopamine D{sub 2} binding capacity in vascular parkinsonism

    Energy Technology Data Exchange (ETDEWEB)

    Terashi, Hiroo; Nagata, Ken; Hirata, Yutaka; Hatazawa, Jun [Research Inst. for Brain and Blood Vessels, Akita (Japan); Utsumi, Hiroya [Tokyo Medical Coll. (Japan)

    2001-10-01

    To investigate whether the striatal dopamine receptor function is involved in the development of vascular parkinsonism (VP), a positron emission tomography (PET) study was conducted on 9 patients with VP by using [{sup 11}C] N-methylspiperone as the tracer. The rate of binding availability in the striatal dopamine D{sub 2} receptor (k{sub 3}) was determined semiquantitatively, and the values were compared to the predicted normal values based on the results from 7 normal volunteers. Of 9 patients with VP, the normalized D{sub 2} receptor binding [%k{sub 3}] was more than 90% in 5 patients, 89 to 87% in 3, and 75% in one. These values showed no evident correlation with the Hoehn and Yahr stage. The laterality of the striatal %k{sub 3} did not correspond to that of the parkinsonism. Thus, the striatal dopamine D{sub 2} receptor binding was not severely impaired and did not correlate with the neurological status in patients with VP. This may indicate that striatal dopamine D{sub 2} receptor function is not primarily associated with the development of the parkinsonism in VP. (author)

  5. Binding induced conformational changes of proteins correlate with their intrinsic fluctuations: a case study of antibodies

    Directory of Open Access Journals (Sweden)

    Keskin Ozlem

    2007-05-01

    Full Text Available Abstract Background How antibodies recognize and bind to antigens can not be totally explained by rigid shape and electrostatic complimentarity models. Alternatively, pre-existing equilibrium hypothesis states that the native state of an antibody is not defined by a single rigid conformation but instead with an ensemble of similar conformations that co-exist at equilibrium. Antigens bind to one of the preferred conformations making this conformation more abundant shifting the equilibrium. Results Here, two antibodies, a germline antibody of 36–65 Fab and a monoclonal antibody, SPE7 are studied in detail to elucidate the mechanism of antibody-antigen recognition and to understand how a single antibody recognizes different antigens. An elastic network model, Anisotropic Network Model (ANM is used in the calculations. Pre-existing equilibrium is not restricted to apply to antibodies. Intrinsic fluctuations of eight proteins, from different classes of proteins, such as enzymes, binding and transport proteins are investigated to test the suitability of the method. The intrinsic fluctuations are compared with the experimentally observed ligand induced conformational changes of these proteins. The results show that the intrinsic fluctuations obtained by theoretical methods correlate with structural changes observed when a ligand is bound to the protein. The decomposition of the total fluctuations serves to identify the different individual modes of motion, ranging from the most cooperative ones involving the overall structure, to the most localized ones. Conclusion Results suggest that the pre-equilibrium concept holds for antibodies and the promiscuity of antibodies can also be explained this hypothesis: a limited number of conformational states driven by intrinsic motions of an antibody might be adequate to bind to different antigens.

  6. Resonance Raman study on indoleamine 2,3-dioxygenase: Control of reactivity by substrate-binding

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, Sachiko; Hara, Masayuki [Graduate School of Life Science and Picobiology Institute, University of Hyogo, Koto 3-2-1, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan); Sugimoto, Hiroshi; Shiro, Yoshitsugu [Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Koto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Ogura, Takashi, E-mail: ogura@sci.u-hyogo.ac.jp [Graduate School of Life Science and Picobiology Institute, University of Hyogo, Koto 3-2-1, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan)

    2013-06-20

    Highlights: • Indoleamine 2,3-dioygenase has been studied by resonance Raman spectroscopy. • Trp-binding to the enzyme induces high frequency shift of the Fe–His stretching mode. • Increased imidazolate character of histidine promotes the O–O bond cleavage step. • A fine-tuning of the reactivity of the O–O bond cleavage reaction is identified. • The results are consistent with the sequential oxygen-atom-transfer mechanism. - Abstract: Resonance Raman spectra of ligand-bound complexes including the 4-phenylimidazole complex and of free and L-Trp-bound forms of indoleamine 2, 3-dioxygenase in the ferric state were examined. Effects on the vinyl and propionate substituent groups of the heme were detected in a ligand-dependent fashion. The effects of phenyl group of 4-phenylimidazole on the vinyl and propionate Raman bands were evident when compared with the case of imidazole ligand. Substrate binding to the ferrous protein caused an upshift of the iron–histidine stretching mode by 3 cm{sup −1}, indicating an increase in negativity of the imidazole ring, which favors the O–O bond cleavage. The substrate binding event is likely to be communicated from the heme distal side to the iron–histidine bond through heme substituent groups and the hydrogen-bond network which includes water molecules, as identified in an X-ray structure of a 4-phenylimidazole complex. The results provide evidence for fine-tuning of the reactivity of O–O bond cleavage by the oxygenated heme upon binding of L-Trp.

  7. Binding of several anti-tumor drugs to bovine serum albumin: Fluorescence study

    Energy Technology Data Exchange (ETDEWEB)

    Bi Shuyun [College of Chemistry, Changchun Normal University, Changchun 130032 (China)], E-mail: sy_bi@sina.com; Sun Yantao [College of Chemistry, Jilin University, Changchun 130023 (China); College of Chemistry, Jilin Normal University, Siping 136000 (China); Qiao Chunyu; Zhang Hanqi [College of Chemistry, Jilin University, Changchun 130023 (China); Liu Chunming [College of Chemistry, Changchun Normal University, Changchun 130032 (China)

    2009-05-15

    The interactions of mitomycin C (MMC), fluorouracil (FU), mercaptopurine (MP) and doxorubicin hydrochloride (DXR) with bovine serum albumin (BSA) were studied by spectroscopic method. Quenching of fluorescence of serum albumin by these drugs was found to be a static quenching process. The binding constants (K{sub A}) were 9.66x10{sup 3}, 2.08x10{sup 3}, 8.20x10{sup 2} and 7.50x10{sup 3} L mol{sup -1} for MMC-, FU-, MP- and DXR-BSA, respectively, at pH 7.4 Britton-Robinson buffer at 28 deg. C. The thermodynamic functions such as enthalpy change ({delta}H), entropy change ({delta}S) and Gibbs free-energy change ({delta}G) for the reactions were also calculated according to the thermodynamic equations. The main forces in the interactions of these drugs with BSA were evaluated. It was found that the interactions of MMC and FU with BSA were exothermic processes and those of MP and DXR with BSA were endothermic. In addition, the binding sites on BSA for the four drugs were probed by the changes of binding properties of these drugs with BSA in the presence of two important site markers such as ibuprofen and indomethacin. Based on the Foester theory of non-radiation energy transfer, the binding distances between the drugs and tryptophane were calculated and they were 3.00, 1.14, 2.85, and 2.79 nm for MMC, FU, MP and DXR, respectively.

  8. A pilot study of a metronomic chemotherapy regimen with weekly low-dose docetaxel for previously treated non-small cell lung cancer

    Directory of Open Access Journals (Sweden)

    Yokoi T

    2012-05-01

    Full Text Available Takashi Yokoi, Takeshi Tamaki, Toshiki Shimizu, Shosaku NomuraFirst Department of Internal Medicine, Kansai Medical University, Moriguchi City, Osaka, JapanBackground: Low-dose metronomic (LDM chemotherapy is a novel approach that involves frequent administration of a low dose of chemotherapeutic agent without a long interval.Purpose: The aim of this clinical pilot study was to evaluate the toxicity and efficacy of LDM chemotherapy with weekly low-dose docetaxel for previously treated non-small cell lung cancer (NSCLC.Patients and methods: The enrolled patients received 15 mg/m2 of docetaxel intravenously on a weekly basis without any interval.Results: Twenty-seven patients were enrolled in the study; 20 were men, and seven were women. The median age was 62 years (range: 32–75. Eleven patients were stage IIIB, and 16 were stage IV. The Eastern Cooperative Oncology Group performance status was 0 or 1. There was no severe hematological adverse effect; importantly, there was no neutropenia or thrombocytopenia. The objective response rate was 7.4% and the disease control rate was 51.9%. The median survival time was 16.4 months (95% CI: 5.7–36.4.Conclusion: Our preliminary results indicate that our metronomic regimen was well tolerated and active in patients with previously treated NSCLC. Thus, further investigation of this LDM regimen is warranted.Keywords: optimal biological dose, metronomic chemotherapy, docetaxel

  9. Outcome of secondary high-grade glioma in children previously treated for a malignant condition: A study of the Canadian Pediatric Brain Tumour Consortium

    International Nuclear Information System (INIS)

    Carret, Anne-Sophie; Tabori, Uri; Crooks, Bruce; Hukin, Juliette; Odame, Isaac; Johnston, Donna L.; Keene, Daniel L.; Freeman, Carolyn; Bouffet, Eric

    2006-01-01

    Background and purpose: Reports of secondary high-grade glioma (HGG) in survivors of childhood cancer are scarce. The aim of this study was to review the pattern of diagnosis, the treatment, and outcome of secondary pediatric HGG. Patients and methods: We performed a multi-center retrospective study among the 17 paediatric institutions participating in the Canadian Pediatric Brain Tumour Consortium (CPBTC). Results: We report on 18 patients (14 males, 4 females) treated in childhood for a primary cancer, who subsequently developed a HGG as a second malignancy. All patients had previously received radiation therapy +/- chemotherapy for either acute lymphoblastic leukaemia (n = 9) or solid tumour (n = 9). All HGG occurred within the previous radiation fields. At the last follow-up, 17 patients have died and the median survival time is 9.75 months. Conclusion: Although aggressive treatment seems to provide sustained remissions in some patients, the optimal management is still to be defined. Further documentation of such cases is necessary in order to better understand the pathogenesis, the natural history and the prevention of these tumours

  10. Does using testicular sperm retrieval rather than ejaculated spermatozoa improve reproductive outcomes in couples with previous ART failure and poor ovarian response? A case-controlled study.

    Science.gov (United States)

    Gilman, A R; Younes, G; Tannus, S; Son, W Y; Chan, P; Buckett, W

    2018-01-01

    The objective of this study was to assess whether testicular-retrieved spermatozoa improve reproductive outcomes compared to fresh ejaculate in women with poor ovarian response and a history of previous ART failure. The study was performed as a retrospective case-control study at a university-based reproductive center in Montreal, Quebec, Canada. Eighteen poor-responder patients were matched 3 : 1 with 54 controls. Poor responders were defined as those with ≤3 oocytes retrieved at oocyte pickup. Cases were identified as poor responders, and only those with previous IVF failure(s) as an indication for testicular-retrieved spermatozoa were included. Controls were age and cycle attempt number matched. All patients were included only once. From January 1, 2009 to December 31, 2015, all patients and controls underwent an IVF cycle using ICSI with either testicular spermatozoa or ejaculated spermatozoa, respectively. Outcomes included live birth rate, pregnancy rate, miscarriage rate, oocyte number, and embryo transfer (ET) day. The results showed live birth rates, pregnancy rates, and miscarriage rates were similar. There were fewer day 2 ETs (8.5% vs. 48.6%, p = 0.01) and more day 5 blastocyst transfers (25.0% vs. 5.4%, p = 0.05) in the testicular sperm retrieval group compared to controls and thus an overall suggestion of better embryo quality in the testicular sperm group. Overall, however, the use of testicular sperm retrieval appears to add little. Women with poor ovarian response typically have a poor prognosis with respect to live birth rates, and this is further supported in this study. The suggestion of better embryo quality in the testicular-retrieved sperm group would need to be further assessed in a larger multicentered study. © 2017 American Society of Andrology and European Academy of Andrology.

  11. Binding thermodynamics of Diclofenac and Naproxen with human and bovine serum albumins: A calorimetric and spectroscopic study

    International Nuclear Information System (INIS)

    Bou-Abdallah, Fadi; Sprague, Samuel E.; Smith, Britannia M.; Giffune, Thomas R.

    2016-01-01

    Highlights: • The binding affinity of Diclofenac and Naproxen to BSA and HSA is on the order of 10 4 –10 6 M −1 . • Two Diclofenac molecules bind per BSA or HSA but only 0.75 and 3 Naproxen molecules bind to BSA and HSA, respectively. • Drugs binding to BSA is only enthalpically favored and both enthalpically and entropically favored for HSA. • Fluorescence quenching data suggest dynamic collisions and the formation of ground-state protein-drug complexes. • DSC data show multiple sequential unfolding events and strong drug stabilization effects. - Abstract: Serum albumins are ubiquitous proteins able to bind a variety of exogenous and endogenous ligands including hydrophobic pharmaceuticals. Most drugs bind to two very active binding regions located within sub-domains IIA and IIIA of the protein, also known as Sudlow’s sites. The drug binding mode of serum albumin provides important pharmacological information and influences drug solubility, efficacy, biological distribution, and excretion. Here, the binding thermodynamics of Diclofenac and Naproxen, two non-steroidal anti-inflammatory drugs (NSAIDs) to bovine and human serum albumins (BSA and HSA, respectively) were studied by isothermal titration calorimetry (ITC), fluorescence spectroscopy and differential scanning calorimetry (DSC). The ITC data show that the binding affinity (K) of Diclofenac to BSA and HSA is on the order of 10 4 M −1 with a binding stoichiometry (n) of 2 drug molecules per protein. Naproxen binding to the two proteins exhibits a different profile with K and n values on the order of 10 6 M −1 and 0.75 for BSA, and 10 5 M −1 and 3 for HSA, respectively. The binding of the two drugs to HSA is found to be both enthalpically and entropically favored suggesting the formation of hydrogen bonds and van der Waals hydrophobic effects. Binding of the two drugs to BSA is only enthalpically favored with an unfavorable entropy term. Significant enthalpy–entropy compensation

  12. ``In silico'' study of the binding of two novel antagonists to the nociceptin receptor

    Science.gov (United States)

    Della Longa, Stefano; Arcovito, Alessandro

    2018-02-01

    Antagonists of the nociceptin receptor (NOP) are raising interest for their possible clinical use as antidepressant drugs. Recently, the structure of NOP in complex with some piperidine-based antagonists has been revealed by X-ray crystallography. In this study, a multi-flexible docking (MF-docking) procedure, i.e. docking to multiple receptor conformations extracted by preliminary molecular dynamics trajectories, together with hybrid quantum mechanics/molecular mechanics (QM/MM) simulations have been carried out to provide the binding mode of two novel NOP antagonists, one of them selective (BTRX-246040, formerly named LY-2940094) and one non selective (AT-076), i.e. able to inactivate NOP as well as the classical µ- k- and δ-opioid receptors (MOP KOP and DOP). According to our results, the pivotal role of residue D1303,32 (upper indexes are Ballesteros-Weinstein notations) is analogous to that enlighten by the already known X-ray structures of opioid receptors: binding of the molecules are predicted to require a slight readjustment of the hydrophobic pocket (residues Y1313,33, M1343,36, I2195,43, Q2806,52 and V2836,55) in the orthosteric site of NOP, accommodating either the pyridine-pyrazole (BTRX-246040) or the isoquinoline (AT-076) moiety of the ligand, in turn allowing the protonated piperidine nitrogen to maximize interaction (salt-bridge) with residue D1303,32 of the NOP, and the aromatic head to be sandwiched in optimal π-stacking between Y1313,33 and M1343,36. The QM/MM optimization after the MF-docking procedure has provided the more likely conformations for the binding to the NOP receptor of BTRX-246040 and AT-076, based on different pharmacophores and exhibiting different selectivity profiles. While the high selectivity for NOP of BTRX-246040 can be explained by interactions with NOP specific residues, the lack of selectivity of AT-076 could be associated to its ability to penetrate into the deep hydrophobic pocket of NOP, while retaining a

  13. Studies on the binding of growth hormone to rabbit liver membranes

    International Nuclear Information System (INIS)

    Hughes, J.P.

    1979-01-01

    The specific binding of rat (r) and rabbit (rb) [ 125 I]iodo-growth hormone (GH) was studied in liver membrane preparations isolated from male, virgin female, late pregnant and midlactating rabbits. Overall, these studies suggest that heterologous radioreceptor assays which use rabbit liver membranes do not provide valid estimates of the potencies of various GH preparations. Furthermore, many assays which measure forms of GH from the same species as the purified standard do not constitute homologous assays since the different forms are not bound in a manner similar to the standard. This latter point is interesting since it suggests that the various forms of rGH may initiate different biological actions

  14. Vitamin D deficiency in medical patients at a central hospital in Malawi: a comparison with TB patients from a previous study.

    Directory of Open Access Journals (Sweden)

    Yamikani Mastala

    Full Text Available OBJECTIVES: To determine the prevalence of vitamin D deficiency (VDD in adult medical, non-tuberculous (non-TB patients. To investigate associations with VDD. To compare the results with a similar study in TB patients at the same hospital. DESIGN: Cross-sectional sample. SETTING: Central hospital in Malawi. PARTICIPANTS: Adult non-TB patients (n = 157, inpatients and outpatients. OUTCOME MEASURES: The primary outcome was the prevalence of VDD. Potentially causal associations sought included nutritional status, in/outpatient status, HIV status, anti-retroviral therapy (ART and, by comparison with a previous study, a diagnosis of tuberculosis (TB. RESULTS: Hypovitaminosis D (≤75 nmol/L occurred in 47.8% (75/157 of patients, 16.6% (26/157 of whom had VDD (≤50 nmol/L. None had severe VDD (≤25 nmol/L. VDD was found in 22.8% (23/101 of in-patients and 5.4% (3/56 of out-patients. In univariable analysis in-patient status, ART use and low dietary vitamin D were significant predictors of VDD. VDD was less prevalent than in previously studied TB patients in the same hospital (68/161 = 42%. In multivariate analysis of the combined data set from both studies, having TB (OR 3.61, 95%CI 2.02-6.43 and being an in-patient (OR 2.70, 95%CI 1.46-5.01 were significant independent predictors of VDD. CONCLUSIONS: About half of adult medical patients without TB have suboptimal vitamin D status, which is more common in in-patients. VDD is much more common in TB patients than non-TB patients, even when other variables are controlled for, suggesting that vitamin D deficiency is associated with TB.

  15. Reduced live-birth rates after IVF/ICSI in women with previous unilateral oophorectomy: results of a multicentre cohort study.

    Science.gov (United States)

    Lind, Tekla; Holte, Jan; Olofsson, Jan I; Hadziosmanovic, Nermin; Gudmundsson, Johannes; Nedstrand, Elizabeth; Lood, Mikael; Berglund, Lars; Rodriguez-Wallberg, Kenny

    2018-02-01

    Is there a reduced live-birth rate (LBR) after IVF/ICSI treatment in women with a previous unilateral oophorectomy (UO)? A significantly reduced LBR after IVF/ICSI was found in women with previous UO when compared with women with intact ovaries in this large multicentre cohort, both crudely and after adjustment for age, BMI, fertility centre and calendar period and regardless of whether the analysis was based on transfer of embryos in the fresh cycle only or on cumulative results including transfers using frozen-thawed embryos. Similar pregnancy rates after IVF/ICSI have been previously reported in case-control studies and small cohort studies of women with previous UO versus women without ovarian surgery. In all previous studies multiple embryos were transferred. No study has previously evaluated LBR in a large cohort of women with a history of UO. This research was a multicentre cohort study, including five reproductive medicine centres in Sweden: Carl von Linné Clinic (A), Karolinska University Hospital (B), Uppsala University Hospital (C), Linköping University Hospital (D) and Örebro University Hospital (E). The women underwent IVF/ICSI between January 1999 and November 2015. Single embryo transfer (SET) was performed in approximately 70% of all treatments, without any significant difference between UO exposed women versus controls (68% versus 71%), respectively (P = 0.32), and a maximum of two embryos were transferred in the remaining cases. The dataset included all consecutive treatments and fresh and frozen-thawed cycles. The exposed cohort included 154 women with UO who underwent 301 IVF/ICSI cycles and the unexposed control cohort consisted of 22 693 women who underwent 41 545 IVF/ICSI cycles. Overall, at the five centres (A-E), the exposed cohort underwent 151, 34, 35, 41 and 40 treatments, respectively, and they were compared with controls of the same centre (18 484, 8371, 5575, 4670 and 4445, respectively). The primary outcome was LBR, which was

  16. Everolimus Plus Exemestane in Advanced Breast Cancer: Safety Results of the BALLET Study on Patients Previously Treated Without and with Chemotherapy in the Metastatic Setting.

    Science.gov (United States)

    Generali, Daniele; Montemurro, Filippo; Bordonaro, Roberto; Mafodda, Antonino; Romito, Sante; Michelotti, Andrea; Piovano, Pierluigi; Ionta, Maria Teresa; Bighin, Claudia; Sartori, Donata; Frassoldati, Antonio; Cazzaniga, Marina Elena; Riccardi, Ferdinando; Testore, Franco; Vici, Patrizia; Barone, Carlo Antonio; Schirone, Alessio; Piacentini, Federico; Nolè, Franco; Molino, Annamaria; Latini, Luciano; Simoncini, Edda Lucia; Roila, Fausto; Cognetti, Francesco; Nuzzo, Francesco; Foglietta, Jennifer; Minisini, Alessandro Marco; Goffredo, Francesca; Portera, Giuseppe; Ascione, Gilda; Mariani, Gabriella

    2017-06-01

    The BALLET study was an open-label, multicenter, expanded access study designed to allow treatment with everolimus plus exemestane in postmenopausal women with hormone receptor-positive metastatic breast cancer progressed following prior endocrine therapy. A post hoc analysis to evaluate if previous chemotherapy in the metastatic setting affects the safety profile of the combination regimen of everolimus and exemestane was conducted on the Italian subset, as it represented the major part of the patients enrolled (54%). One thousand one hundred and fifty-one Italian patients were included in the present post hoc analysis, which focused on two sets of patients: patients who never received chemotherapy in the metastatic setting (36.1%) and patients who received at least one chemotherapy treatment in the metastatic setting (63.9%). One thousand one hundred and sixteen patients (97.0%) prematurely discontinued the study drug, and the main reasons reported were disease progression (39.1%), local reimbursement of everolimus (31.1%), and adverse events (AEs) (16.1%). The median duration of study treatment exposure was 139.5 days for exemestane and 135.0 days for everolimus. At least one AE was experienced by 92.5% of patients. The incidence of everolimus-related AEs was higher (83.9%) when compared with those that occurred with exemestane (29.1%), and the most commonly reported everolimus-related AE was stomatitis (51.3%). However, no significant difference in terms of safety related to the combination occurred between patients without and with chemotherapy in the metastatic setting. Real-life data of the Italian patients BALLET-related cohort were an adequate setting to state that previous chemotherapy did not affect the safety profile of the combination regimen of everolimus and exemestane. With the advent of new targeted agents for advanced or metastatic breast cancer, multiple lines of therapy may be possible, and components of the combined regimens can overlap from

  17. Study on the bindings of dichlorprop and diquat dibromide herbicides to human serum albumin by spectroscopic methods

    Energy Technology Data Exchange (ETDEWEB)

    Tunç, Sibel, E-mail: stunc@akdeniz.edu.tr; Duman, Osman, E-mail: osmanduman@akdeniz.edu.tr; Soylu, İnanç; Kancı Bozoğlan, Bahar

    2014-05-01

    Highlights: • The affinity of DCP to HSA is higher than DQ. • DCP and DQ have quenched the fluorescence emission spectrum of HSA by static quenching mechanism. • Electrostatic interactions are very important in HSA-DCP and HSA-DQ complexes. • Binding constants, numbers of binding sites and thermodynamic parameters have been calculated. • The binding of DQ changes the conformation of protein, on the contrary to DCP. - Abstract: The interactions of dichlorprop (DCP) and diquat dibromide (DQ) herbicides with human serum albumin (HSA) protein were studied by UV absorption, fluorescence, synchronous fluorescence and circular dichroism (CD) spectroscopy. Both DCP and DQ quenched the fluorescence emission spectrum of HSA through the static quenching mechanism. The Stern–Volmer quenching constant, binding constant, the number of binding sites and thermodynamic parameters were determined at 288 K, 298 K, 310 K and 318 K. In HSA-DCP and HSA-DQ systems, an increase in temperature led to a decrease in the Stern–Volmer quenching constant and binding constant. One binding site was obtained for DCP and DQ on HSA. It was found that DCP can bind to HSA with higher affinity than DQ. Negative ΔH and positive ΔS values were obtained for the binding processes between protein and herbicide molecules. This result displayed that electrostatic interactions play a major role in the formation of HSA-DCP and HSA-DQ complexes. The binding processes were exothermic reactions and spontaneous. In addition, synchronous fluorescence and CD spectra of HSA revealed that the binding of DCP to HSA did not cause a significant conformational change in protein, but the interaction of DQ with HSA led to an alteration in the protein structure.

  18. Higher frequency of hamstring injuries in elite track and field athletes who had a previous injury to the ankle - a 17 years observational cohort study.

    Science.gov (United States)

    Malliaropoulos, Nikolaos; Bikos, Georgios; Meke, Maria; Vasileios, Korakakis; Valle, Xavier; Lohrer, Heinz; Maffulli, Nicola; Padhiar, Nat

    2018-01-01

    Inversion injury to the ankle and hamstring injuries are common problems in most sports. It is not known whether these injuries constitute a predisposing factor or a precursor of injury or re-injury of these anatomical locations. Therefore, we wished to test the hypothesis that a previous inversion ankle injury exerted a significant effect on the chance of an athlete suffering from a subsequent ipsilateral hamstring injury and vice versa. In an observational cohort study over 17 years (1998-2015), 367 elite track and field athletes, were grouped according to their first traumatic isolated ankle or hamstring injury. Fifty athletes experienced both injuries. The Mann-Whitney U and Chi-square tests ( p  < 0.05) were performed to test possible associations of ankle and hamstring injury with age, gender, athletics discipline, grade, and type of antecedent injury. Athletes with a preceding ankle injury had a statistically significantly higher chance of experiencing a subsequent hamstring injury compared with athletes who had experienced a hamstring injury as their first traumatic event (x 2  = 4.245, p  = 0.039). The proportion of both ankle and hamstring injury events was not statistically different between female (18%) and male (11%) athletes. Age and grade of injury did not influence the proportion of ankle and/or hamstring injury events. There is a statistically significantly higher frequency of hamstring injuries in elite track and field athletes having experienced a previous ankle ligament injury.

  19. Phenanthrene binding by humic acid–protein complexes as studied by passive dosing technique

    International Nuclear Information System (INIS)

    Zhao, Jian; Wang, Zhenyu; Ghosh, Saikat; Xing, Baoshan

    2014-01-01

    This work investigated the binding behavior of phenanthrene by humic acids (HA-2 and HA-5), proteins (bovine serum albumin (BSA)), lysozyme and pepsin), and their complexes using a passive dosing technique. All sorption isotherms were fitted well with Freundlich model and the binding capability followed an order of HA-5 > HA-2 > BSA > pepsin > lysozyme. In NaCl solution, phenanthrene binding to HA-BSA complexes was much higher than the sum of binding to individual HA and BSA, while there was no enhancement for HA-pepsin. Positively charged lysozyme slightly lowered phenanthrene binding on both HAs due to strong aggregation of HA-lysozyme complexes, leading to reduction in the number of binding sites. The binding enhancement by HA-BSA was observed under all tested ion species and ionic strengths. This enhancement can be explained by unfolding of protein, reduction of aggregate size and formation of HA-BSA complexes with favorable conformations for binding phenanthrene. Highlights: • Phenanthrene binding capability followed an order: HA-5>HA-2>BSA>pepsin>lysozyme. • Phenanthrene binding to HA-BSA was enhanced relative to individual HA and BSA. • Binding enhancement to HA-BSA was observed under all tested solution conditions. • The enhancement is related to BSA unfolding, size reduction and HA-BSA complexation. -- Phenanthrene binding to HA-BSA complexes is much higher than the sum to individual HA and BSA while there was no binding enhancement to HA-pepsin or HA-lysozyme

  20. A longitudinal study of relationships between previous academic achievement, emotional intelligence and personality traits with psychological health of medical students during stressful periods.

    Science.gov (United States)

    Yusoff, Muhamad Saiful Bahri; Esa, Ab Rahman; Mat Pa, Mohamad Najib; Mey, See Ching; Aziz, Rosniza Abdul; Abdul Rahim, Ahmad Fuad

    2013-01-01

    There is considerable evidence that emotional intelligence, previous academic achievement (i.e. cumulative grade point average (GPA)) and personality are associated with success in various occupational settings. This study evaluated the relationships of these variables with psychological health of first year medical students during stressful periods. A 1-year prospective study was done with students accepted into the School of Medical Sciences, Universiti Sains Malaysia. Information on emotional intelligence, GPA and personality traits were obtained prior to admission. The validated Universiti Sains Malaysia Emotional Quotient Inventory and Universiti Sains Malaysia Personality Inventory were used to measure emotional intelligence and personality traits, respectively. Stress, anxiety and depression were measured by the 21-item Depression Anxiety Stress Scale during the end-of-course (time 1) and final (time 2) examinations. At the less stressful period (time 1), stress level was associated with agreeableness and the final GPA, anxiety level was associated with emotional control and emotional conscientiousness and depression level was associated with the final GPA and extraversion. At the more stressful period (time 2), neuroticism associated with stress level, anxiety level was associated with neuroticism and emotional expression, and depression level was associated with neuroticism. This study found that neuroticism was the strongest associated factor of psychological health of medical students during their most stressful testing period. Various personality traits, emotional intelligence and previous academic performance were associated factors of psychological health during a less stressful period. These data suggest that early identification of medical students who are vulnerable to the stressful environment of medical schools might help them maintain psychological well-being during medical training.

  1. A COMPARATIVE STUDY OF PERINATAL OUTCOME IN WOMEN WITH RECURRENT PREECLAMPSIA TO WOMEN WITH PRE-ECLAMPSIA WHO WERE NORMOTENSIVE DURING THEIR PREVIOUS PREGNANCIES

    Directory of Open Access Journals (Sweden)

    Beena Guhan

    2016-08-01

    Full Text Available BACKGROUND AND OBJECTIVE Pre-eclampsia is a systemic syndrome that occurs in 3-5% of the pregnant women and is the leading cause of maternal/neonatal morbidity and mortality. We designed a study to compare perinatal outcome in women with recurrent preeclampsia to women with women with pre-eclampsia who were normotensive during their previous pregnancies. MATERIALS AND METHODS This study was conducted in Dept. of Obstetrics and Gynaecology, Institute of Maternal and Child Health, Government Medical College, Kozhikode for a period of 1 year from March 2013 to February 2014. We conducted this study in multiparous women who developed pre-eclampsia in index pregnancy (n=110. Among these, women who had pre-eclampsia in previous pregnancies (n=55 were compared to those who remained normotensive during their prior pregnancies (n=55. Maternal and foetal variables were compared. Multivariate logistic analyses were performed to examine the impact of pre-eclampsia on foetal outcome, preterm delivery, IUGR, still births adjusted for confounding variables. RESULTS No statistical significant difference was observed between the 2 groups in terms of age, gravida, parity. Women who experienced recurrent pre-eclampsia were at elevated risk for early onset of pre-eclampsia, deranged laboratory investigations (Hepatic and Renal parameters, Coagulation Profile, higher chances of maternal complications, foetal mortality and morbidity (Statistically significant P <0.05. Foetal loss was higher in women with recurrent pre-eclampsia (14.5% than in women with pre-eclampsia who had normotensive pregnancy history (1.8%. CONCLUSION Women with recurrent pre-eclampsia had a higher rate of perinatal loss compared to women with pre-eclampsia who were normotensive in their prior pregnancies.

  2. Tight binding simulation study on zigzag single-walled carbon nanotubes

    Science.gov (United States)

    Sharma, Deepa; Jaggi, Neena; Gupta, Vishu

    2018-01-01

    Tight binding simulation studies using the density functional tight binding (DFTB) model have been performed on various zigzag single-walled carbon-nanotubes (SWCNTs) to investigate their electronic properties using DFTB module of the Material Studio Software version 7.0. Various combinations of different eigen-solvers and charge mixing schemes available in the DFTB Module have been tried to chalk out the electronic structure. The analytically deduced values of the bandgap of (9, 0) SWCNT were compared with the experimentally determined value reported in the literature. On comparison, it was found that the tight binding approximations tend to drastically underestimate the bandgap values. However, the combination of Anderson charge mixing method with standard eigensolver when implemented using the smart algorithm was found to produce fairly close results. These optimized model parameters were then used to determine the band structures of various zigzag SWCNTs. (9, 0) Single-walled Nanotube which is extensively being used for sensing NH3, CH4 and NO2 has been picked up as a reference material since its experimental bandgap value has been reported in the literature. It has been found to exhibit a finite energy bandgap in contrast to its expected metallic nature. The study is of utmost significance as it not only probes and validates the simulation route for predicting suitable properties of nanomaterials but also throws light on the comparative efficacy of the different approximation and rationalization quantum mechanical techniques used in simulation studies. Such simulation studies if used intelligently prove to be immensely useful to the material scientists as they not only save time and effort but also pave the way to new experiments by making valuable predictions.

  3. The screening and functional study of proteins binding with the BmNPV polyhedrin promoter.

    Science.gov (United States)

    Yu, Wei; Li, Jia; Wang, Meihui; Quan, Yanping; Chen, Jian; Nie, Zuoming; Lv, Zhengbing; Zhang, Yaozhou

    2012-05-06

    The polyhedrin gene promoter has an essential role in regulating foreign gene expression in baculovirus expression vector systems (BEVS); however, the high-level transcription mechanism is still unknown. One-hybrid screening in yeast is a powerful way of identifying rapidly heterologous transcription factors that can interact with the polyhedrin promoter DNA sequence. In the current study, total RNA was extracted from the fat bodies of fifth-instar silkworm larvae that had been infected with Bombyx mori nuclear polyhedrosis virus (BmNPV) for 5 days; complementary DNA (cDNA) was then generated using reverse-transcription (RT)-PCR to construct a silkworm gene expression library. Key polyhedrin promoter bait sequences were synthesized to generate a bait yeast strain, which was used to screen the one-hybrid cDNA library. In total, 12 positive yeast colonies were obtained from the SD/-Leu/AbA plates; sequencing analysis showed that they belong to two different protein cDNA colonies. Positive colonies underwent bioinformatics analysis, which revealed one colony to be ribosomal proteins [B. mori ribosomal protein SA (BmRPSA)] and the other to be NPV DNA-binding proteins (DBP). To further verify the regulatory function of these two protein groups, transient expression vectors (pSK-IE-dbp and pSK-IE-BmRPSA) were constructed. The recombinant plasmids were then transfected into cultured B. mori N (BmN) cells, which had been infected with a recombinant bacmid containing the gene encoding luciferase (luc). The results showed that overexpression of either dbp or BmRPSA upregulated the polh promoter-driven transcription of luc in BmN cells. In addition, dbp or BmRPSA RNA interference (RNAi) resulted in the downregulation of luciferase reporter expression in BmN cells, demonstrating that DBP and BmRPSA are important for luc transcription. EMSA results further confirmed that DBP could directly bind to the conserved single-stranded polh promoter region in intro. However, EMSA

  4. The screening and functional study of proteins binding with the BmNPV polyhedrin promoter

    Directory of Open Access Journals (Sweden)

    Yu Wei

    2012-05-01

    Full Text Available Abstract Background The polyhedrin gene promoter has an essential role in regulating foreign gene expression in baculovirus expression vector systems (BEVS; however, the high-level transcription mechanism is still unknown. One-hybrid screening in yeast is a powerful way of identifying rapidly heterologous transcription factors that can interact with the polyhedrin promoter DNA sequence. In the current study, total RNA was extracted from the fat bodies of fifth-instar silkworm larvae that had been infected with Bombyx mori nuclear polyhedrosis virus (BmNPV for 5 days; complementary DNA (cDNA was then generated using reverse-transcription (RT-PCR to construct a silkworm gene expression library. Key polyhedrin promoter bait sequences were synthesized to generate a bait yeast strain, which was used to screen the one-hybrid cDNA library. Results In total, 12 positive yeast colonies were obtained from the SD/-Leu/AbA plates; sequencing analysis showed that they belong to two different protein cDNA colonies. Positive colonies underwent bioinformatics analysis, which revealed one colony to be ribosomal proteins [B. mori ribosomal protein SA (BmRPSA] and the other to be NPV DNA-binding proteins (DBP. To further verify the regulatory function of these two protein groups, transient expression vectors (pSK-IE-dbp and pSK-IE-BmRPSA were constructed. The recombinant plasmids were then transfected into cultured B. mori N (BmN cells, which had been infected with a recombinant bacmid containing the gene encoding luciferase (luc. The results showed that overexpression of either dbp or BmRPSA upregulated the polh promoter-driven transcription of luc in BmN cells. In addition, dbp or BmRPSA RNA interference (RNAi resulted in the downregulation of luciferase reporter expression in BmN cells, demonstrating that DBP and BmRPSA are important for luc transcription. EMSA results further confirmed that DBP could directly bind to the conserved single-stranded polh

  5. The mode of inhibitor binding to peptidyl-tRNA hydrolase: binding studies and structure determination of unbound and bound peptidyl-tRNA hydrolase from Acinetobacter baumannii.

    Science.gov (United States)

    Kaushik, Sanket; Singh, Nagendra; Yamini, Shavait; Singh, Avinash; Sinha, Mau; Arora, Ashish; Kaur, Punit; Sharma, Sujata; Singh, Tej P

    2013-01-01

    The incidences of infections caused by an aerobic Gram-negative bacterium, Acinetobacter baumannii are very common in hospital environments. It usually causes soft tissue infections including urinary tract infections and pneumonia. It is difficult to treat due to acquired resistance to available antibiotics is well known. In order to design specific inhibitors against one of the important enzymes, peptidyl-tRNA hydrolase from Acinetobacter baumannii, we have determined its three-dimensional structure. Peptidyl-tRNA hydrolase (AbPth) is involved in recycling of peptidyl-tRNAs which are produced in the cell as a result of premature termination of translation process. We have also determined the structures of two complexes of AbPth with cytidine and uridine. AbPth was cloned, expressed and crystallized in unbound and in two bound states with cytidine and uridine. The binding studies carried out using fluorescence spectroscopic and surface plasmon resonance techniques revealed that both cytidine and uridine bound to AbPth at nanomolar concentrations. The structure determinations of the complexes revealed that both ligands were located in the active site cleft of AbPth. The introduction of ligands to AbPth caused a significant widening of the entrance gate to the active site region and in the process of binding, it expelled several water molecules from the active site. As a result of interactions with protein atoms, the ligands caused conformational changes in several residues to attain the induced tight fittings. Such a binding capability of this protein makes it a versatile molecule for hydrolysis of peptidyl-tRNAs having variable peptide sequences. These are the first studies that revealed the mode of inhibitor binding in Peptidyl-tRNA hydrolases which will facilitate the structure based ligand design.

  6. The mode of inhibitor binding to peptidyl-tRNA hydrolase: binding studies and structure determination of unbound and bound peptidyl-tRNA hydrolase from Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Sanket Kaushik

    Full Text Available The incidences of infections caused by an aerobic Gram-negative bacterium, Acinetobacter baumannii are very common in hospital environments. It usually causes soft tissue infections including urinary tract infections and pneumonia. It is difficult to treat due to acquired resistance to available antibiotics is well known. In order to design specific inhibitors against one of the important enzymes, peptidyl-tRNA hydrolase from Acinetobacter baumannii, we have determined its three-dimensional structure. Peptidyl-tRNA hydrolase (AbPth is involved in recycling of peptidyl-tRNAs which are produced in the cell as a result of premature termination of translation process. We have also determined the structures of two complexes of AbPth with cytidine and uridine. AbPth was cloned, expressed and crystallized in unbound and in two bound states with cytidine and uridine. The binding studies carried out using fluorescence spectroscopic and surface plasmon resonance techniques revealed that both cytidine and uridine bound to AbPth at nanomolar concentrations. The structure determinations of the complexes revealed that both ligands were located in the active site cleft of AbPth. The introduction of ligands to AbPth caused a significant widening of the entrance gate to the active site region and in the process of binding, it expelled several water molecules from the active site. As a result of interactions with protein atoms, the ligands caused conformational changes in several residues to attain the induced tight fittings. Such a binding capability of this protein makes it a versatile molecule for hydrolysis of peptidyl-tRNAs having variable peptide sequences. These are the first studies that revealed the mode of inhibitor binding in Peptidyl-tRNA hydrolases which will facilitate the structure based ligand design.

  7. Prevalence of high-risk human papillomavirus and cervical intraepithelial neoplasias in a previously unscreened population--a pooled analysis from three studies.

    Science.gov (United States)

    Basu, Partha; Mittal, Srabani; Bhaumik, Suchismita; Mandal, Shyam Sunder; Samaddar, Anusree; Ray, Chinmayi; Siddiqi, Maqsood; Biswas, Jaydip; Sankaranarayanan, Rengaswamy

    2013-04-01

    Population prevalence of human papillomavirus (HPV) and cervical intraepithelial neoplasias (CIN) is an important indicator to judge the disease burden in the community, to monitor the performance of cervical cancer screening program and to assess the impact of HPV vaccination program. India being a country without any cervical cancer screening program has no published data on the population prevalence of CIN and only a few large community-based studies to report the high-risk HPV prevalence. The objective of our study was to study HPV and CIN prevalence in a previously unscreened population. We pooled together the results of three research studies originally designed to assess the performance of visual inspection after acetic acid application and Hybrid Capture 2 (HC 2). Nearly 60% of the screened women had colposcopy irrespective of their screening test results. The diagnosis and grading of cervical neoplasias were based on histology. The age standardized prevalence of HPV by HC 2 test was 6.0%. Age-adjusted prevalence of CIN1 and CIN2 was 2.3% and 0.5%, respectively. The age-adjusted prevalence of CIN3 was 0.4% and that of invasive cancer was 0.2%. The prevalence of high-risk HPV was relatively low in the population we studied, which is reflected in the low prevalence of high-grade CIN. The prevalence of CIN3 remained constant across age groups due to absence of screening. Copyright © 2012 UICC.

  8. Phase II study of a 3-day schedule with topotecan and cisplatin in patients with previously untreated small cell lung cancer and extensive disease

    DEFF Research Database (Denmark)

    Sorensen, M.; Lassen, Ulrik Niels; Jensen, Peter Buhl

    2008-01-01

    and cisplatin are needed. The aim of this phase II study was to establish the response rate and response duration in chemo-naive patients with SCLC receiving a 3-day topotecan and cisplatin schedule. METHODS: Simons optimal two-stage design was used. Patients with previously untreated extensive disease SCLC......INTRODUCTION: Treatment with a topoisomerase I inhibitor in combination with a platinum results in superior or equal survival compared with etoposide-based treatment in extensive disease small cell lung cancer (SCLC). Five-day topotecan is inconvenient and therefore shorter schedules of topotecan......, adequate organ functions and performance status less than 3 were eligible. Topotecan (2.0 mg/m, intravenously) was administered on days 1 to 3 with cisplatin (50 mg/m, intravenously) on day 3 every 3 weeks for a total of six cycles. RESULTS: Forty-three patients received 219 cycles of chemotherapy. Median...

  9. EXPERIMENTAL CHALLENGE STUDY OF FV3-LIKE RANAVIRUS INFECTION IN PREVIOUSLY FV3-LIKE RANAVIRUS INFECTED EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) TO ASSESS INFECTION AND SURVIVAL.

    Science.gov (United States)

    Hausmann, Jennifer C; Wack, Allison N; Allender, Matthew C; Cranfield, Mike R; Murphy, Kevin J; Barrett, Kevin; Romero, Jennell L; Wellehan, James F X; Blum, Stella A; Zink, M Christine; Bronson, Ellen

    2015-12-01

    The Maryland Zoo in Baltimore experienced an outbreak of Frog virus-3 (FV3)-like ranavirus during the summer of 2011, during which 14 of 27 (52%) of its captive eastern box turtles (Terrapene carolina carolina) survived. To assess survival, immunity, and viral shedding, an experimental challenge study was performed in which the surviving, previously infected turtles were reinfected with the outbreak strain of FV3-like ranavirus. Seven turtles were inoculated with virus intramuscularly and four control turtles received saline intramuscularly. The turtles were monitored for 8 wk with blood and oral swabs collected for quantitative polymerase chain reaction (qPCR). During that time, one of seven (14%) inoculated turtles and none of the controls (0%) died; there was no significant difference in survival. Clinical signs of the inoculated turtles, except for the turtle that died, were mild compared to the original outbreak. Quantitative PCR for FV3-like ranavirus on blood and oral swabs was positive for all inoculated turtles and negative for all controls. The turtle that died had intracytoplasmic inclusion bodies in multiple organs. Three inoculated and two control turtles were euthanized at the end of the study. No inclusion bodies were present in any of the organs. Quantitative PCR detected FV3-like ranavirus in the spleen of a control turtle, which suggested persistence of the virus. The surviving five turtles were qPCR-negative for FV3-like ranavirus from blood and oral swabs after brumation. Quantitative PCR for Terrapene herpesvirus 1 found no association between ranavirus infection and herpesvirus loads. In conclusion, previously infected eastern box turtles can be reinfected with the same strain of FV3-like ranavirus and show mild to no clinical signs but can shed the virus from the oral cavity.

  10. Studies of cellulose binding by cellobiose dehydrogenase and a comparison with cellobiohydrolase 1.

    OpenAIRE

    Henriksson, G; Salumets, A; Divne, C; Pettersson, G

    1997-01-01

    The binding isotherm to cellulose of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium has been compared with that of cellobiohydrolase 1 (CBH 1) from Trichoderma reesei. CDH binds more strongly but more sparsely to cellulose than does CBH 1. In a classical Scatchard analysis, a better fit to a one-site binding model was obtained for CDH than for CBH 1. The binding of both enzymes decreased in the presence of ethylene glycol, increased in the presence of ammonium sulphate and wa...

  11. Sequential memory: Binding dynamics

    Science.gov (United States)

    Afraimovich, Valentin; Gong, Xue; Rabinovich, Mikhail

    2015-10-01

    Temporal order memories are critical for everyday animal and human functioning. Experiments and our own experience show that the binding or association of various features of an event together and the maintaining of multimodality events in sequential order are the key components of any sequential memories—episodic, semantic, working, etc. We study a robustness of binding sequential dynamics based on our previously introduced model in the form of generalized Lotka-Volterra equations. In the phase space of the model, there exists a multi-dimensional binding heteroclinic network consisting of saddle equilibrium points and heteroclinic trajectories joining them. We prove here the robustness of the binding sequential dynamics, i.e., the feasibility phenomenon for coupled heteroclinic networks: for each collection of successive heteroclinic trajectories inside the unified networks, there is an open set of initial points such that the trajectory going through each of them follows the prescribed collection staying in a small neighborhood of it. We show also that the symbolic complexity function of the system restricted to this neighborhood is a polynomial of degree L - 1, where L is the number of modalities.

  12. Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

    International Nuclear Information System (INIS)

    Arnold, John

    2015-01-01

    The uranyl cation (UO 2 2+ ) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

  13. Structural Studies of Nicotinic Acetylcholine Receptors: Using Acetylcholine-Binding Protein as a Structural Surrogate.

    Science.gov (United States)

    Shahsavar, Azadeh; Gajhede, Michael; Kastrup, Jette S; Balle, Thomas

    2016-06-01

    Nicotinic acetylcholine receptors (nAChRs) are members of the pentameric ligand-gated ion channel superfamily that play important roles in the control of neurotransmitter release in the central and peripheral nervous system. These receptors are important therapeutic targets for the development of drugs against a number of mental health disorders and for marketed smoking cessation aids. Unfortunately, drug discovery has been hampered by difficulties in obtaining sufficiently selective compounds. Together with functional complexity of the receptors, this has made it difficult to obtain drugs with sufficiently high-target to off-target affinity ratios. The recent and ongoing progress in structural studies holds promise to help understand structure-function relationships of nAChR drugs at the atomic level. This will undoubtedly lead to the design of more efficient drugs with fewer side effects. As a high-resolution structure of a nAChR is yet to be determined, structural studies are to a large extent based on acetylcholine-binding proteins (AChBPs) that despite low overall sequence identity display a high degree of conservation of overall structure and amino acids at the ligand-binding site. Further, AChBPs reproduce relative binding affinities of ligands at nAChRs. Over the past decade, AChBPs have been used extensively as models for nAChRs and have aided the understanding of drug receptor interactions at nAChRs significantly. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  14. Selectivity in ligand binding to uranyl compounds: A synthetic, structural, thermodynamic and computational study

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, John [Univ. of California, Berkeley, CA (United States)

    2015-01-21

    The uranyl cation (UO₂²⁺) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. It is anticipated that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials. The focus of this study is to synthesize uranyl complexes incorporating amidinate and guanidinate ligands. Both synthetic and computational methods are used to investigate novel equatorial ligand coordination and how this affects the basicity of the oxo ligands. Such an understanding will later apply to designing ligands incorporating functionalities that can bind uranyl both equatorially and axially for highly selective sequestration. Efficient and durable chromatography supports for lanthanide separation will be generated by (1) identifying robust peptoid-based ligands capable of binding different lanthanides with variable affinities, and (2) developing practical synthetic methods for the attachment of these ligands to Dowex ion exchange resins.

  15. Women's decision-making processes and the influences on their mode of birth following a previous caesarean section in Taiwan: a qualitative study.

    Science.gov (United States)

    Chen, Shu-Wen; Hutchinson, Alison M; Nagle, Cate; Bucknall, Tracey K

    2018-01-17

    Vaginal birth after caesarean (VBAC) is an alternative option for women who have had a previous caesarean section (CS); however, uptake is limited because of concern about the risks of uterine rupture. The aim of this study was to explore women's decision-making processes and the influences on their mode of birth following a previous CS. A qualitative approach was used. The research comprised three stages. Stage I consisted of naturalistic observation at 33-34 weeks' gestation. Stage II involved interviews with pregnant women at 35-37 weeks' gestation. Stage III consisted of interviews with the same women who were interviewed postnatally, 1 month after birth. The research was conducted in a private medical centre in northern Taiwan. Using a purposive sampling, 21 women and 9 obstetricians were recruited. Data collection involved in-depth interviews, observation and field notes. Constant comparative analysis was employed for data analysis. Ensuring the safety of mother and baby was the focus of women's decisions. Women's decisions-making influences included previous birth experience, concern about the risks of vaginal birth, evaluation of mode of birth, current pregnancy situation, information resources and health insurance. In communicating with obstetricians, some women complied with obstetricians' recommendations for repeat caesarean section (RCS) without being informed of alternatives. Others used four step decision-making processes that included searching for information, listening to obstetricians' professional judgement, evaluating alternatives, and making a decision regarding mode of birth. After birth, women reflected on their decisions in three aspects: reflection on birth choices; reflection on factors influencing decisions; and reflection on outcomes of decisions. The health and wellbeing of mother and baby were the major concerns for women. In response to the decision-making influences, women's interactions with obstetricians regarding birth choices

  16. Molecular dynamics study of zinc binding to cysteines in a peptide mimic of the alcohol dehydrogenase structural zinc site.

    Science.gov (United States)

    Brandt, Erik G; Hellgren, Mikko; Brinck, Tore; Bergman, Tomas; Edholm, Olle

    2009-02-14

    The binding of zinc (Zn) ions to proteins is important for many cellular events. The theoretical and computational description of this binding (as well as that of other transition metals) is a challenging task. In this paper the binding of the Zn ion to four cysteine residues in the structural site of horse liver alcohol dehydrogenase (HLADH) is studied using a synthetic peptide mimic of this site. The study includes experimental measurements of binding constants, classical free energy calculations from molecular dynamics (MD) simulations and quantum mechanical (QM) electron structure calculations. The classical MD results account for interactions at the molecular level and reproduce the absolute binding energy and the hydration free energy of the Zn ion with an accuracy of about 10%. This is insufficient to obtain correct free energy differences. QM correction terms were calculated from density functional theory (DFT) on small clusters of atoms to include electronic polarisation of the closest waters and covalent contributions to the Zn-S coordination bond. This results in reasonably good agreement with the experimentally measured binding constants and Zn ion hydration free energies in agreement with published experimental values. The study also includes the replacement of one cysteine residue to an alanine. Simulations as well as experiments showed only a small effect of this upon the binding free energy. A detailed analysis indicate that the sulfur is replaced by three water molecules, thereby changing the coordination number of Zn from four (as in the original peptide) to six (as in water).

  17. Effect of treatment of a previous ectopic pregnancy on in vitro fertilization-intracytoplasmic sperm injection outcomes: a retrospective cohort study.

    Science.gov (United States)

    Xu, Zhen; Yan, Lei; Liu, Wen; Xu, Xinxin; Li, Miao; Ding, Lingling; Ma, Jinlong; Chen, Zi-Jiang

    2015-12-01

    To evaluate the influence of previous ectopic pregnancies (EP) and different EP treatment methods on in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) outcomes. Retrospective cohort study. University-based reproductive medicine center. Women undergoing 51,268 fresh cycles of IVF-ICSI. In women who had had an EP before the IVF treatment and women who were diagnosed with fallopian disease without an EP (control group), division into three treatment subgroups: subgroup 1, conservative treatment; subgroup 2, salpingostomy; and subgroup 3 salpingectomy. Estimates of IVF-ICSI outcome and ovarian function based on number of antral follicles and rates of implantation, EP, clinical pregnancy, and delivery. For the experimental group and the control group, there were no statistically significant differences in the rates of implantation, clinical pregnancy, or delivery. However, the risk of recurrent EP was statistically significantly higher in the experimental group compared with the control group. There were no statistically significant differences in IVF-ICSI outcomes between the three treatment subgroups in terms of the basic antral follicle number or the dominant antral follicle numbers (>1.0 cm) after surgical treatment of EP. Our results suggest that women with a prior history of EP have a higher recurrence risk of EP after IVF in comparison with women with no history of EP. Previous EP has no effect on the main IVF-ICSI outcomes. For the treatment of EP, salpingostomy and salpingectomy do not statistically significantly affect ovarian function. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  18. Direct binding of ethanol to bovine serum albumin: a fluorescent and 13C NMR multiplet relaxation study.

    Science.gov (United States)

    Avdulov, N A; Chochina, S V; Daragan, V A; Schroeder, F; Mayo, K H; Wood, W G

    1996-01-09

    Molecular mechanisms of ethanol interaction with proteins are not well-understood. In the present study, direct interaction of ethanol with hydrophobic binding sites on fatty acid free bovine serum albumin (BSA) was determined using the fluorescent probe 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS), cis-parinaric acid, and 13C NMR. The affinity of ethanol for BSA (Kd) was (5.21 +/- 0.31) x 10(-2) mol. Ethanol (25-200 mmol) competitively inhibited 1,8-ANS binding to BSA in a concentration-dependent manner with a Ki (concentration of ethanol that decreased 1,8-ANS binding by 50%) of 658 mmol. Preincubation of BSA with ethanol significantly decreased cis-parinaric acid binding to BSA, indicating interaction of ethanol with hydrophobic fatty acid-binding site(s) on BSA. Furthermore, ethanol was found to act on three of the five fatty acid-binding sites on BSA. These data indicated selectivity in the interaction of ethanol with hydrophobic sites on BSA. 13C NMR multiplet relaxation was used to characterize the interaction of ethanol with binding sites on BSA. Detailed analysis of [13C]ethanol relaxation data obtained in the presence of increasing BSA concentrations (25-200 mg/mL) led to the conclusion that the ethanol methyl group, as opposed to its hydroxyl group, binds in a hydrophobic pocket(s) on the protein. Ethanol-induced changes in activity of certain proteins may result from direct binding of ethanol to specific hydrophobic binding sites and/or displacement of endogenous ligands from those sites.

  19. Two consecutive phase II studies of oxaliplatin (L-OHP) for treatment of patients with advanced colorectal carcinoma who were resistant to previous treatment with fluoropyrimidines.

    Science.gov (United States)

    Machover, D; Diaz-Rubio, E; de Gramont, A; Schilf, A; Gastiaburu, J J; Brienza, S; Itzhaki, M; Metzger, G; N'Daw, D; Vignoud, J; Abad, A; Francois, E; Gamelin, E; Marty, M; Sastre, J; Seitz, J F; Ychou, M

    1996-01-01

    Oxaliplatin (L-OHP) is a platinum complex that possesses activity against human and murine cells in vitro and in vivo, including colorectal carcinoma-derived cell lines, and cells that have been selected for resistance to cisplatin. We report two consecutive phase II trials of L-OHP for treatment of patients with advanced colorectal carcinoma. Fifty-eight patients were entered in study I, and 51 patients in study II. All of the patients had tumor progression when they were treated, prior to their enrollment, with a fluoropyrimidine-containing regimen. In both trials treatment consisted of L-OHP, 130 mg/m2, by i.v. infusion for two hours; the treatment was repeated every 21 days. Response to therapy: Study I: Fifty-five patients were assessed for response. The response rate was 11% (95% CI, 0.03-0.19). Study II: All 51 patients were assessed for response. The response rate was 10% (95% CI, 0.017-0.18). The overall response rate for the 106 evaluated patients was 10% (95% CI, 0.046-0.16). Times to disease progression in responders were 4, 4, 4.5+, 5, 5, 6, 6, 6, 6+, 9, and 13 months. The dose-limiting toxic effect was sensory peripheral neuropathy. The incidence of severe peripheral neuropathy grades was: Study I: grade 3, 23% of patients, and grade 4, 8% of patients. Severe neuropathy had a favorable course in all of the patients who had long-term neurologic follow-up. Diarrhea and myeloid impairment were minor. L-OHP produced modest, but definite antitumor activity in patients with advanced colorectal carcinoma who were previously resistant to chemotherapy including fluoropyrimidines. Toxicity is within acceptable limits of tolerance at the dose and schedule of oxaliplatin used in this trial.

  20. Structural and functional studies of conserved nucleotide-binding protein LptB in lipopolysaccharide transport

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhongshan [Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, NR4 7TJ (United Kingdom); College of Life Sciences, Sichuan University, Chengdu 610065 (China); Biomedical Sciences Research Complex, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST (United Kingdom); Xiang, Quanju [College of Life Sciences, Sichuan University, Chengdu 610065 (China); Biomedical Sciences Research Complex, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST (United Kingdom); Department of Microbiology, College of Resource and Environment Science, Sichuan Agriculture University, Yaan 625000 (China); Zhu, Xiaofeng [College of Life Sciences, Sichuan University, Chengdu 610065 (China); Dong, Haohao [Biomedical Sciences Research Complex, School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST (United Kingdom); He, Chuan [School of Electronics and Information, Wuhan Technical College of Communications, No. 6 Huangjiahu West Road, Hongshan District, Wuhan, Hubei 430065 (China); Wang, Haiyan; Zhang, Yizheng [College of Life Sciences, Sichuan University, Chengdu 610065 (China); Wang, Wenjian, E-mail: Wenjian166@gmail.com [Laboratory of Department of Surgery, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, Guangdong 510080 (China); Dong, Changjiang, E-mail: C.Dong@uea.ac.uk [Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, NR4 7TJ (United Kingdom)

    2014-09-26

    Highlights: • Determination of the structure of the wild-type LptB in complex with ATP and Mg{sup 2+}. • Demonstrated that ATP binding residues are essential for LptB’s ATPase activity and LPS transport. • Dimerization is required for the LptB’s function and LPS transport. • Revealed relationship between activity of the LptB and the vitality of E. coli cells. - Abstract: Lipopolysaccharide (LPS) is the main component of the outer membrane of Gram-negative bacteria, which plays an essential role in protecting the bacteria from harsh conditions and antibiotics. LPS molecules are transported from the inner membrane to the outer membrane by seven LPS transport proteins. LptB is vital in hydrolyzing ATP to provide energy for LPS transport, however this mechanism is not very clear. Here we report wild-type LptB crystal structure in complex with ATP and Mg{sup 2+}, which reveals that its structure is conserved with other nucleotide-binding proteins (NBD). Structural, functional and electron microscopic studies demonstrated that the ATP binding residues, including K42 and T43, are crucial for LptB’s ATPase activity, LPS transport and the vitality of Escherichia coli cells with the exceptions of H195A and Q85A; the H195A mutation does not lower its ATPase activity but impairs LPS transport, and Q85A does not alter ATPase activity but causes cell death. Our data also suggest that two protomers of LptB have to work together for ATP hydrolysis and LPS transport. These results have significant impacts in understanding the LPS transport mechanism and developing new antibiotics.

  1. Lysine-functionalized nanodiamonds: synthesis, physiochemical characterization, and nucleic acid binding studies

    Science.gov (United States)

    Kaur, Randeep; Chitanda, Jackson M; Michel, Deborah; Maley, Jason; Borondics, Ferenc; Yang, Peng; Verrall, Ronald E; Badea, Ildiko

    2012-01-01

    Purpose: Detonation nanodiamonds (NDs) are carbon-based nanomaterials that, because of their size (4–5 nm), stable inert core, alterable surface chemistry, fluorescence, and biocompatibility, are emerging as bioimaging agents and promising tools for the delivery of biochemical molecules into cellular systems. However, diamond particles possess a strong propensity to aggregate in liquid formulation media, restricting their applicability in biomedical sciences. Here, the authors describe the covalent functionalization of NDs with lysine in an attempt to develop nanoparticles able to act as suitable nonviral vectors for transferring genetic materials across cellular membranes. Methods: NDs were oxidized and functionalized by binding lysine moieties attached to a three-carbon-length linker (1,3-diaminopropane) to their surfaces through amide bonds. Raman and Fourier transform infrared spectroscopy, zeta potential measurement, dynamic light scattering, atomic force microscopic imaging, and thermogravimetric analysis were used to characterize the lysine-functionalized NDs. Finally, the ability of the functionalized diamonds to bind plasmid DNA and small interfering RNA was investigated by gel electrophoresis assay and through size and zeta potential measurements. Results: NDs were successfully functionalized with the lysine linker, producing surface loading of 1.7 mmol g−1 of ND. These modified NDs formed highly stable aqueous dispersions with a zeta potential of 49 mV and particle size of approximately 20 nm. The functionalized NDs were found to be able to bind plasmid DNA and small interfering RNA by forming nanosized “diamoplexes”. Conclusion: The lysine-substituted ND particles generated in this study exhibit stable aqueous formulations and show potential for use as carriers for genetic materials. PMID:22904623

  2. Lysine-functionalized nanodiamonds: synthesis, physiochemical characterization, and nucleic acid binding studies.

    Science.gov (United States)

    Kaur, Randeep; Chitanda, Jackson M; Michel, Deborah; Maley, Jason; Borondics, Ferenc; Yang, Peng; Verrall, Ronald E; Badea, Ildiko

    2012-01-01

    Detonation nanodiamonds (NDs) are carbon-based nanomaterials that, because of their size (4-5 nm), stable inert core, alterable surface chemistry, fluorescence, and biocompatibility, are emerging as bioimaging agents and promising tools for the delivery of biochemical molecules into cellular systems. However, diamond particles possess a strong propensity to aggregate in liquid formulation media, restricting their applicability in biomedical sciences. Here, the authors describe the covalent functionalization of NDs with lysine in an attempt to develop nanoparticles able to act as suitable nonviral vectors for transferring genetic materials across cellular membranes. NDs were oxidized and functionalized by binding lysine moieties attached to a three-carbon-length linker (1,3-diaminopropane) to their surfaces through amide bonds. Raman and Fourier transform infrared spectroscopy, zeta potential measurement, dynamic light scattering, atomic force microscopic imaging, and thermogravimetric analysis were used to characterize the lysine-functionalized NDs. Finally, the ability of the functionalized diamonds to bind plasmid DNA and small interfering RNA was investigated by gel electrophoresis assay and through size and zeta potential measurements. NDs were successfully functionalized with the lysine linker, producing surface loading of 1.7 mmol g(-1) of ND. These modified NDs formed highly stable aqueous dispersions with a zeta potential of 49 mV and particle size of approximately 20 nm. The functionalized NDs were found to be able to bind plasmid DNA and small interfering RNA by forming nanosized "diamoplexes". The lysine-substituted ND particles generated in this study exhibit stable aqueous formulations and show potential for use as carriers for genetic materials.

  3. Structural and functional studies of conserved nucleotide-binding protein LptB in lipopolysaccharide transport

    International Nuclear Information System (INIS)

    Wang, Zhongshan; Xiang, Quanju; Zhu, Xiaofeng; Dong, Haohao; He, Chuan; Wang, Haiyan; Zhang, Yizheng; Wang, Wenjian; Dong, Changjiang

    2014-01-01

    Highlights: • Determination of the structure of the wild-type LptB in complex with ATP and Mg 2+ . • Demonstrated that ATP binding residues are essential for LptB’s ATPase activity and LPS transport. • Dimerization is required for the LptB’s function and LPS transport. • Revealed relationship between activity of the LptB and the vitality of E. coli cells. - Abstract: Lipopolysaccharide (LPS) is the main component of the outer membrane of Gram-negative bacteria, which plays an essential role in protecting the bacteria from harsh conditions and antibiotics. LPS molecules are transported from the inner membrane to the outer membrane by seven LPS transport proteins. LptB is vital in hydrolyzing ATP to provide energy for LPS transport, however this mechanism is not very clear. Here we report wild-type LptB crystal structure in complex with ATP and Mg 2+ , which reveals that its structure is conserved with other nucleotide-binding proteins (NBD). Structural, functional and electron microscopic studies demonstrated that the ATP binding residues, including K42 and T43, are crucial for LptB’s ATPase activity, LPS transport and the vitality of Escherichia coli cells with the exceptions of H195A and Q85A; the H195A mutation does not lower its ATPase activity but impairs LPS transport, and Q85A does not alter ATPase activity but causes cell death. Our data also suggest that two protomers of LptB have to work together for ATP hydrolysis and LPS transport. These results have significant impacts in understanding the LPS transport mechanism and developing new antibiotics

  4. Binding of Cimetidine to Balb/C Mouse Liver Catalase; Kinetics and Conformational Studies.

    Science.gov (United States)

    Jahangirvand, Mahboubeh; Minai-Tehrani, Dariush; Yazdi, Fatemeh; Minai-Tehrani, Arash; Razmi, Nematollah

    2016-01-01

    Catalase is responsible for converting hydrogen peroxide (H2O2) into water and oxygen in cells. This enzyme has high affinity for hydrogen peroxide and can protect the cells from oxidative stress damage. Catalase is a tetramer protein and each monomer contains a heme group. Cimetidine is a histamine H2 receptor blocker which inhibits acid release from stomach and is used for gasterointestinal diseases. In this research, effect of cimetidine on the activity of liver catalase was studied and the kinetic parameters of this enzyme and its conformational changes were investigated. Cell free extract of mouse liver was used for the catalase assay. The activity of the catalase was detected in the absence and presence of cimetidine by monitoring hydrogen peroxide reduction absorbance at 240 nm. The purified enzyme was used for conformational studies by Fluorescence spectrophotometry. The data showed that cimetidine could inhibit the enzyme in a non-competitive manner. Ki and IC50 values of the drug were determined to be about 0.75 and 0.85 uM, respectively. The Arrhenius plot showed that activation energy was 6.68 and 4.77 kJ/mol in the presence and absence of the drug, respectively. Fluorescence spectrophotometry revealed that the binding of cimetidine to the purified enzyme induced hyperchromicity and red shift which determined the conformational change on the enzyme. Cimetidine could non-competitively inhibit the liver catalase with high affinity. Binding of cimetidine to the enzyme induced conformational alteration in the enzyme.

  5. Binding of the neuroleptic drug, gabapentin, to bovine serum albumin: Insights from experimental and computational studies

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Fahimeh, E-mail: fahimehjalali@yahoo.com [Department of Chemistry, Razi University, 67346 Kermanshah (Iran, Islamic Republic of); Dorraji, Parisa S. [Department of Chemistry, Razi University, 67346 Kermanshah (Iran, Islamic Republic of); Mahdiuni, Hamid [Department of Biology, Razi University, 67346 Kermanshah (Iran, Islamic Republic of)

    2014-04-15

    The interaction between antiepileptic drug, gabapentin (GP), and bovin serum albumin (BSA) was studied by spectroscopic and computational methods. The native fluorescence of BSA was quenched by GP. Stern–Volmer quenching constant was calculated at different temperatures which suggested a static mechanism. The association constant (K{sub a}) was calculated from fluorescence quenching studies, which increased with temperature rising. GP competed well with warfarine for hydrophobic subdomain IIA (Sudlow's site I) on the protein. Enthalpy and entropy changes during the interaction of GP with BSA were obtained using van't Hoff plot, which showed an entropy-driven process and involvement of hydrophobic forces (ΔH>0 and ΔS>0). Synchronous fluorescence measurements of BSA solution in the presence of GP showed a considerable blue shift when Δλ=15 nm, therefore, GP interacts with tyrosine-rich sites on BSA. Optimized docked model of BSA–GP mixture confirmed the experimental results. -- Highlights: • Interaction of gabapentin and bovine serum albumin (BSA) is investigated by spectroscopic techniques. • Gabapentin can quench the fluorescence of BSA through a static quenching procedure. • The binding of gabapentin to BSA is driven mainly by hydrophobic interactions. • Subdomain IIA (Sudlow's site I) of BSA is found to be the main binding site for gabapentin. • Molecular docking modeling confirmed the experimental results.

  6. The priming effect of previous natural pandemic H1N1 infection on the immunogenicity to subsequent 2010-2011 influenza vaccination in children: a prospective cohort study.

    Science.gov (United States)

    Kang, Eun Kyeong; Eun, Byung Wook; Kim, Nam Hee; Lim, Jung Sub; Lee, Jun Ah; Kim, Dong Ho

    2016-08-22

    The effect of previous natural pandemic H1N1 (H1N1 pdm09) influenza infection on the immunogenicity to subsequent inactivated influenza vaccination in children has not been well studied. We aimed to evaluate the effect of H1N1 pdm09 natural infection and vaccination on the immunogenicity to subsequent 2010-2011 seasonal inactivated influenza vaccination in children. From October 2010 to May 2011, we conducted an open-label, multi-center study in children aged 6 months -18 years in Korea. We measured antibody titers with a hemagglutination-inhibition (HI) assay at baseline, 1 month, and 6 months after vaccination with trivalent split or subunit vaccines containing H1N1 pdm, A/H3N2, and B. The subjects were classified into 4 groups depending on the presence of laboratory-confirmed H1N1 pdm09 infection and/or vaccination in the 2009-2010 season; Group I: vaccination (-)/infection(-), Group II: vaccination (-)/infection(+), Group III: vaccination (+)/infection(-), Group IV: vaccination (+)/infection(+). Among the subjects in group I, 47 subjects who had a baseline titer >1:10 were considered to have an asymptomatic infection. They were included into the final group II (n = 80). We defined the new group II as the infection-primed (IP) group and group III as the vaccine-primed (VP) group. Seroconversion rate (57.5 % vs 35.9 %, p = 0.001), seroprotection rate at 6 months after vaccination (70.8 % vs 61.8 %, p = 0.032), and GMT at 1 month after vaccination (129.9 vs 66.5, p = 0.002) were significantly higher in the IP group than in the VP group. In the 9-18 year-old group, seroconversion rate and immunogenicity at 1 and 6 months were significantly higher in the IP group than in the VP group. However in the 1-7 year-old age group, there was no significant difference between the two groups. Previous H1N1 pdm09 infection appears to have positive effects on immunogenicity of subsequent inactivated influenza vaccines against H1N1 pdm09 in older

  7. Homology Modeling Study of Bovine μ-Calpain Inhibitor-Binding Domains

    Directory of Open Access Journals (Sweden)

    Han-Ha Chai

    2014-05-01

    Full Text Available The activated mammalian CAPN-structures, the CAPN/CAST complex in particular, have become an invaluable target model using the structure-based virtual screening of drug candidates from the discovery phase to development for over-activated CAPN linked to several diseases, such as post-ischemic injury and cataract formation. The effect of Ca2+-binding to the enzyme is thought to include activation, as well as the dissociation, aggregation, and autolysis of small regular subunits. Unfortunately, the Ca2+-activated enzyme tends to aggregate when provided as a divalent ion at the high-concentration required for the protease crystallization. This is also makes it very difficult to crystallize the whole-length enzyme itself, as well as the enzyme-inhibitor complex. Several parameters that influence CAPN activity have been investigated to determine its roles in Ca2+-modulation, autoproteolysis, phosphorylation, and intracellular distribution and inhibition by its endogenous inhibitor CAST. CAST binds and inhibits CAPN via its CAPN-inhibitor domains (four repeating domains 1–4; CAST1–4 when CAPN is activated by Ca2+-binding. An important key to understanding CAPN1 inhibition by CAST is to determine how CAST interacts at the molecular level with CAPN1 to inhibit its protease activity. In this study, a 3D structure model of a CAPN1 bound bovine CAST4 complex was built by comparative modeling based on the only known template structure of a rat CAPN2/CAST4 complex. The complex model suggests certain residues of bovine CAST4, notably, the TIPPKYQ motif sequence, and the structural elements of these residues, which are important for CAPN1 inhibition. In particular, as CAST4 docks near the flexible active site of CAPN1, conformational changes at the interaction site after binding could be directly related to CAST4 inhibitory activity. These functional interfaces can serve as a guide to the site-mutagenesis in research on bovine CAPN1 structure

  8. Application of Sperm Selection Using Hyaluronic Acid Binding in Intracytoplasmic Sperm Injection Cycles: A Sibling Oocyte Study

    Science.gov (United States)

    Choe, Seung Ah; Tae, Jin Chul; Shin, Mi Young; Kim, Hyun Jung; Kim, Chung Hyon; Lee, Joong Yeup; Hwang, Doyeong; Kim, Ki Chul; Suh, Chang Suk

    2012-01-01

    The purpose of this study was to investigate whether sperm selection by hyaluronic acid (HA) binding could improve fertilization rate and embryo quality in intracytoplasmic sperm injection (ICSI) cycles. Two hundred nineteen oocytes obtained from eighteen women were injected with either HA-bound (n = 107) or conventionally selected spermatozoa (n = 112) in a randomized way. All of the participants were infertile couples who had normal sperm parameters but low fertilization rate in previous in vitro fertilization (IVF) cycle (n = 5) or experienced multiple IVF failures (n = 13). Lower fertilization (75.7% vs 83.0%) and cleavage rate on day 2 (72.9% vs 83.0%) was observed in oocytes injected with HA-bound spermatozoa than the conventional group, but the difference was not significant. Significantly lower cleavage rate was observed on day 3 in HA group (56.0% vs 69.6%, P = 0.038). Blastocyst formation rate and the number of transferred embryos were similar in both groups. In multiple IVF failure patients, significantly reduced fertilization rate (71.8% vs 85.3%, P = 0.046) and cleavage rate on day 2 (70.4% vs 85.3%, P = 0.029) and day 3 (53.5% vs 77.3%, P = 0.002) were noticed in HA group. Five women achieved pregnancy continuing more than 12 weeks after transfer (27.8%). Success of ICSI was not related with the number of embryos fertilized by HA-bound spermatozoa. Application of ICSI by sperm selection using HA binding is not helpful in couples with repeated poor fertilization or implantation despite normal sperm parameters. PMID:23255860

  9. A prospective flexible-dose study of paliperidone palmitate in nonacute but symptomatic patients with schizophrenia previously unsuccessfully treated with oral antipsychotic agents.

    Science.gov (United States)

    Schreiner, Andreas; Bergmans, Paul; Cherubin, Pierre; Keim, Sofia; Rancans, Elmars; Bez, Yasin; Parellada, Eduard; Carpiniello, Bernardo; Vidailhet, Pierre; Hargarter, Ludger

    2014-10-01

    The goal of this study was to explore the tolerability, safety, and treatment response of flexible doses of once-monthly paliperidone palmitate (PP) in the subset of nonacute but symptomatic adult patients with schizophrenia previously unsuccessfully treated with oral antipsychotic agents in the PALMFlexS (Paliperidone Palmitate Flexible Dosing in Schizophrenia) study. This was an interventional, single-arm, international, multicenter, unblinded, 6-month study performed in patients with schizophrenia. Patients were categorized according to reasons for switching. In patients switching because of lack of efficacy or for other reasons, primary efficacy outcomes were the proportion achieving treatment response (defined as ≥20% improvement in Positive and Negative Syndrome Scale [PANSS] total score from baseline to last-observation-carried-forward end point) and maintained efficacy (defined as noninferiority in the change in PANSS total score at end point versus baseline [Schuirmann's test]), respectively. A total of 593 patients (intention-to-treat population) were enrolled: 63.1% were male; their mean (SD) age was 38.4 (11.8) years; and 78.6% had paranoid schizophrenia. The main reasons for transition to PP were patient's wish (n = 259 [43.7%]), lack of efficacy (n = 144 [24.3%]), lack of compliance (n = 138 [23.3%]), and lack of tolerability (n = 52 [8.8%]) with the previous oral antipsychotic medication. The recommended PP initiation regimen (150 milligram equivalents [mg eq] day 1 and 100 mg eq day 8) was administered in 93.9% of patients. Mean PANSS total score decreased from 71.5 (14.6) at baseline to 59.7 (18.1) at end point (mean change, -11.7 [15.9]; 95% CI, -13.0 to -10.5; P < 0.0001). Sixty-four percent of patients showed an improvement of ≥20% in PANSS total score, and the percentage of patients rated mildly ill or less in Clinical Global Impression-Severity increased from 31.8% to 63.2%. Mean personal and social performance total score (SD) increased

  10. Safety and tolerability of frovatriptan in the acute treatment of migraine and prevention of menstrual migraine: Results of a new analysis of data from five previously published studies.

    Science.gov (United States)

    MacGregor, E Anne; Pawsey, Stephen P; Campbell, John C; Hu, Xiaojun

    2010-04-01

    Triptans are a recommended first-line treatment for moderate to severe migraine. Using clinical trial data, we evaluated the safety and tolerability of frovatriptan as acute treatment (AT) and as short-term preventive (STP) therapy for menstrual migraine (MM). Data from 2 Phase III AT trials (AT1: randomized, placebo controlled, 1 attack; AT2: 12-months, noncomparative, open label) and 3 Phase IIIb STP trials in MM (MMP1 and MMP2: randomized, placebo controlled, double blind, 3 perimenstrual periods; MMP3: open label, noncomparative, 12 perimenstrual periods) were analyzed. In AT1, patients treated each attack with frovatriptan 2.5 mg, sumatriptan 100 mg, or placebo. In AT2, they used frovatriptan 2.5 mg. In MMP1 and MMP2, women administered frovatriptan 2.5 mg for 6 days during the perimenstrual period, taking a loading dose of 2 or 4 tablets on day 1, followed by once-daily or BID frovatriptan 2.5 mg, respectively; in MMP3, they used BID frovatriptan 2.5 mg. In AT1, which was previously published in part, group differences in adverse events (AEs) were analyzed using the Fisher exact test, and response rates were compared using logistic regression. Post hoc analyses of sustained pain-free status with no AEs (SNAE) and sustained pain response with no AEs (SPRNAE) were performed using a 2-sample test for equality of proportions without continuity correction. For AT2 and the STP studies, data were summarized using descriptive statistics. Results of individual safety analyses for the STP studies were previously reported; the present report includes new results from a pooled analysis of MMP1 and MMP2 and a new analysis of MMP3 in which AEs were coded using Medical Dictionary for Regulatory Activities version 8.0. AT1 included 1206 patients in the safety group; AT2 included 496. In the STP studies, safety data were collected for 1487 women. In AT1 and AT2, 85.6% and 88.3%, respectively, of enrolled patients were women. Overall, AEs were generally mild to moderate (AT

  11. 14N NMR Spectroscopy Study of Binding Interaction between Sodium Azide and Hydrated Fullerene

    Directory of Open Access Journals (Sweden)

    Tamar Chachibaia

    2017-04-01

    Full Text Available Our study is the first attempt to study the interaction between NaN3 and hydrated fullerenes C60 by means of a non-chemical reaction-based approach. The aim is to study deviations of signals obtained by 14N NMR spectroscopy to detect the binding interaction between sodium azide and hydrated fullerene. We considered 14N NMR spectroscopy as one of the most suitable methods for the characterization of azides to show resonance signals corresponding to the three non-equivalent nitrogen atoms. The results demonstrate that there are changes in the chemical shift positions and line-broadening, which are related to the different molar ratios of NaN3:C60 in the samples.

  12. 2D spectroscopy study of water-soluble chlorophyll-binding protein from Lepidium virginicum.

    Science.gov (United States)

    Alster, Jan; Lokstein, Heiko; Dostál, Jakub; Uchida, Akira; Zigmantas, Donatas

    2014-04-03

    Water-soluble chlorophyll-binding proteins (WSCPs) are interesting model systems for the study of pigment-pigment and pigment-protein interactions. While class IIa WSCP has been extensively studied by spectroscopic and theoretical methods, a comprehensive spectroscopic study of class IIb WSCP was lacking so far despite the fact that its structure was determined by X-ray crystallography. In this paper, results of two-dimensional electronic spectroscopy applied to the class IIb WSCP from Lepidium virginicum are presented. Global analysis of 2D data allowed determination of energy levels and excitation energy transfer pathways in the system. Some additional pathways, not present in class IIa WSCP, were observed. The data were interpreted in terms of a model comprising two interacting chlorophyll dimers. In addition, oscillatory signals were observed and identified as coherent beatings of vibrational origin.

  13. In vitro evaluation of oestrogenic/androgenic activity of the serum organochlorine pesticide mixtures previously described in a breast cancer case–control study

    International Nuclear Information System (INIS)

    Rivero, Javier; Luzardo, Octavio P.; Henríquez-Hernández, Luis A.; Machín, Rubén P.; Pestano, José; Zumbado, Manuel; Boada, Luis D.; Camacho, María; Valerón, Pilar F.

    2015-01-01

    Some organochlorine pesticides (OCs) have been individually linked to breast cancer (BC) because they exert oestrogenic effects on mammary cells. However, humans are environmentally exposed to more or less complex mixtures of these organochlorines, and the biological effects of these mixtures must be elucidated. In this work we evaluated the in vitro effects exerted on human BC cells by the OC mixtures that were most frequently detected in two groups of women who participated in a BC case–control study developed in Spain: healthy women and women diagnosed with BC. The cytotoxicity, oestrogenicity, and androgenicity of the most prevalent OC mixtures found in healthy women (H-mixture) and in BC patients (BC-mixture) were tested at concentrations that resembled those found in the serum of the evaluated women. Our results showed that both OC mixtures presented a similar oestrogenic activity and effect on cell viability, but BC-mixture showed an additional anti-androgenic effect. These results indicate that although the proliferative effect exerted by these mixtures on human breast cells seems to depend mainly on their oestrogenic action, the BC-mixture might additionally induce cell proliferation due to its anti-androgenic activity, therefore increasing the carcinogenic potential of this mixture. The findings of this study demonstrate that subtle variations in the composition of a mixture may induce relevant changes in its biological action. - Highlights: • E-screen and A-screen of two mixtures of organochlorine pesticides (OCP) • Assay concentrations based on a previous breast cancer case–control study • Only non-cytotoxic concentrations assayed • Both OCP mixtures induce proliferation mediated by oestrogen receptor. • OCP mixture of breast cancer patients exhibits additional androgenic activity.

  14. In vitro evaluation of oestrogenic/androgenic activity of the serum organochlorine pesticide mixtures previously described in a breast cancer case–control study

    Energy Technology Data Exchange (ETDEWEB)

    Rivero, Javier; Luzardo, Octavio P., E-mail: octavio.perez@ulpgc.es; Henríquez-Hernández, Luis A.; Machín, Rubén P.; Pestano, José; Zumbado, Manuel; Boada, Luis D.; Camacho, María; Valerón, Pilar F.

    2015-12-15

    Some organochlorine pesticides (OCs) have been individually linked to breast cancer (BC) because they exert oestrogenic effects on mammary cells. However, humans are environmentally exposed to more or less complex mixtures of these organochlorines, and the biological effects of these mixtures must be elucidated. In this work we evaluated the in vitro effects exerted on human BC cells by the OC mixtures that were most frequently detected in two groups of women who participated in a BC case–control study developed in Spain: healthy women and women diagnosed with BC. The cytotoxicity, oestrogenicity, and androgenicity of the most prevalent OC mixtures found in healthy women (H-mixture) and in BC patients (BC-mixture) were tested at concentrations that resembled those found in the serum of the evaluated women. Our results showed that both OC mixtures presented a similar oestrogenic activity and effect on cell viability, but BC-mixture showed an additional anti-androgenic effect. These results indicate that although the proliferative effect exerted by these mixtures on human breast cells seems to depend mainly on their oestrogenic action, the BC-mixture might additionally induce cell proliferation due to its anti-androgenic activity, therefore increasing the carcinogenic potential of this mixture. The findings of this study demonstrate that subtle variations in the composition of a mixture may induce relevant changes in its biological action. - Highlights: • E-screen and A-screen of two mixtures of organochlorine pesticides (OCP) • Assay concentrations based on a previous breast cancer case–control study • Only non-cytotoxic concentrations assayed • Both OCP mixtures induce proliferation mediated by oestrogen receptor. • OCP mixture of breast cancer patients exhibits additional androgenic activity.

  15. Binding activity of patterned concanavalin A studied by atomic force microscopy

    International Nuclear Information System (INIS)

    Lebed, Kateryna; Pyka-Fosciak, Grazyna; Raczkowska, Joanna; Lekka, Malgorzata; Styczen, Jan

    2005-01-01

    The mode of protein immobilization plays a crucial role in the preparation of protein microarrays used for a wide spectrum of applications in analytical biochemistry. The microcontact printing technique was used to form a protein pattern using concanavalin A (Con A) since Con A belongs to a group of proteins widely used in analytical assays due to their selectivity as regards different kinds of carbohydrates. Atomic force microscopy was used to image surface topography, delivering information about the quality of the protein pattern. The force spectroscopy mode was used to verify the functional activity of deposited proteins via determination of the forces of interaction between Con A and carboxypeptidase Y bearing carbohydrate structure recognized by Con A. The calculated binding force between Con A and CaY was 105 ± 2 pN and it was compared with that measured for Con A deposited directly from the protein solution. The similarity of the value obtained for the interaction force was independent of the mode of protein deposition, thereby verifying that the microcontact printing technique did not influence the carbohydrate binding activity of Con A. The correlation between the surface topography of patterned samples and adhesion maps obtained showed the possible use of AFM for studying the chemical properties of different regions of the micropatterns produced

  16. Studies on the binding of fulvic acid with transferrin by spectroscopic analysis

    Science.gov (United States)

    Zhang, Xiu-feng; Yang, Guang; Dong, Yu; Zhao, Yan-qin; Sun, Xiao-ran; Chen, Lei; Chen, Hong-bo

    2015-02-01

    Transferrin has shown potential in the delivery of anticancer drugs into primarily proliferating cancer cells that over-express transferrin receptors. Fulvic acid has a wide range of biological and pharmacological activities which caused widespread concerns, the interaction of fulvic acid with human serum transferrin (Tf) has great significance for gaining a deeper insight about anticancer activities of fulvic acid. In this study, the mechanism of interaction between fulvic acid and Tf, has been investigated by using fluorescence quenching, thermodynamics, synchronous fluorescence and circular dichroism (CD) under physiological condition. Our results have shown that fulvic acid binds to Tf and form a new complex, and the calculated apparent association constants are 5.04 × 108 M-1, 5.48 × 107 M-1, 7.38 × 106 M-1 from the fluorescence quenching at 288 K, 298 K, and 310 K. The thermodynamic parameters indicate that hydrogen bonding and weak van der Waals are involved in the interaction between fulvic acid and Tf. The binding of fulvic acid to Tf causes the α-helix structure content of the protein to reduce, and resulting that peptide chains of Tf become more stretched. Our results have indicated a mechanism of the interaction between fulvic acid and Tf, which may provide information for possible design of methods to deliver drug molecules via transferrin to target tissues and cells effectively.

  17. Studies on binding interactions between clenbuterol hydrochloride and two serum albumins by multispectroscopic approaches in vitro.

    Science.gov (United States)

    Wang, Qin; Zhang, Shengrui

    2014-08-01

    In this study, binding properties of clenbuterol hydrochloride (CL) with human serum albumin (HSA) and bovine serum albumin (BSA) were examined using constant protein concentrations and various CL contents under physiological conditions. The binding parameters were confirmed using fluorescence quenching spectroscopy at various temperatures. The experimental results confirmed that the quenching mechanisms of CL and HSA/BSA were both static quenching processes. The thermodynamic parameters, namely, enthalpy change (ΔH) and entropy change (ΔS), were calculated according to the van't Hoff equation, which suggested that the electrostatic interactions were the predominant intermolecular forces in stabilizing the CL-HSA complex, and hydrogen bonds and van der Waals force were the predominant intermolecular forces in stabilizing the CL-BSA complex. Furthermore, the conformational changes of HSA/BSA in the presence of CL were determined using the data obtained from three-dimensional fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy and circular dichroism spectroscopy. Copyright © 2013 John Wiley & Sons, Ltd.

  18. Analysis of sequencing data for probing RNA secondary structures and protein-RNA binding in studying posttranscriptional regulations.

    Science.gov (United States)

    Hu, Xihao; Wu, Yang; Lu, Zhi John; Yip, Kevin Y

    2016-11-01

    High-throughput sequencing has been used to study posttranscriptional regulations, where the identification of protein-RNA binding is a major and fast-developing sub-area, which is in turn benefited by the sequencing methods for whole-transcriptome probing of RNA secondary structures. In the study of RNA secondary structures using high-throughput sequencing, bases are modified or cleaved according to their structural features, which alter the resulting composition of sequencing reads. In the study of protein-RNA binding, methods have been proposed to immuno-precipitate (IP) protein-bound RNA transcripts in vitro or in vivo By sequencing these transcripts, the protein-RNA interactions and the binding locations can be identified. For both types of data, read counts are affected by a combination of confounding factors, including expression levels of transcripts, sequence biases, mapping errors and the probing or IP efficiency of the experimental protocols. Careful processing of the sequencing data and proper extraction of important features are fundamentally important to a successful analysis. Here we review and compare different experimental methods for probing RNA secondary structures and binding sites of RNA-binding proteins (RBPs), and the computational methods proposed for analyzing the corresponding sequencing data. We suggest how these two types of data should be integrated to study the structural properties of RBP binding sites as a systematic way to better understand posttranscriptional regulations. © The Author 2015. Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  19. Immunogenicity and safety of tetravalent dengue vaccine in 2-11 year-olds previously vaccinated against yellow fever: randomized, controlled, phase II study in Piura, Peru.

    Science.gov (United States)

    Lanata, Claudio F; Andrade, Teresa; Gil, Ana I; Terrones, Cynthia; Valladolid, Omar; Zambrano, Betzana; Saville, Melanie; Crevat, Denis

    2012-09-07

    In a randomized, placebo-controlled, monocenter, observer blinded study conducted in an area where dengue is endemic, we assessed the safety and immunogenicity of a recombinant, live, attenuated, tetravalent dengue vaccine candidate (CYD-TDV) in 2-11 year-olds with varying levels of pre-existing yellow-fever immunity due to vaccination 1-7 years previously. 199 children received 3 injections of CYD-TDV (months 0, 6 and 12) and 99 received placebo (months 0 and 6) or pneumococcal polysaccharide vaccine (month 12). One month after the third dengue vaccination, serotype specific neutralizing antibody GMTs were in the range of 178-190 (1/dil) (versus 16.7-38.1 in the control group), a 10-20 fold-increase from baseline, and 94% of vaccines were seropositive to all four serotypes (versus 39% in the control group). There were no vaccine-related SAEs. The observed reactogenicity profile was consistent with phase I studies, with severity grade 1-2 injection site pain, headache, malaise and fever most frequently reported and no increase after subsequent vaccinations. Virologically confirmed dengue cases were seen after completion of the 3 doses: 1 in the CYD-TDV group (N=199), and 3 in the control group (N=99). A 3-dose regimen of CYD-TDV had a good safety profile in 2-11 year olds with a history of YF vaccination and elicited robust antibody responses that were balanced against the four serotypes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. A real life study of Helicobacter pylori eradication with bismuth quadruple therapy in naïve and previously treated patients

    Directory of Open Access Journals (Sweden)

    Blas José Gómez-Rodríguez

    Full Text Available Objective: To evaluate the efficacy and safety of a quadruple regimen (BMTO of the "3-in-1 capsule" (containing bismuth subcitrate potassium, metronidazole and tetracycline plus omeprazole in naïve and previously treated patients diagnosed with Helicobacter pylori (H. pylori infection in the clinical setting in Seville (Spain. Methods: This is a prospective study carried out on consecutive patients with a confirmed H. pylori infection and upper gastrointestinal symptoms. After providing their informed consent, the patients were treated for ten days with a 3-in-1 capsule containing bismuth subcitrate potassium (140 mg, metronidazole (125 mg and tetracycline (125 mg: Pylera®, three capsules four times daily, plus omeprazole (20 or 40 mg twice daily. Eradication of infection was determined by a negative urea breath test at least 28 days after the end of treatment. Results: A total of 58 consecutive patients were enrolled into this study, two of whom withdrew early due to vomiting on days three and five, respectively. In this cohort, 17 patients (29.3% had a prior history of medication to treat H. pylori. In the intent-to-treat population, eradication was achieved in 97.6% (40/41 and 82.4% (14/17 of cases in patients treated with BMTO as a first-line or rescue therapy, respectively. At least one adverse event was reported by 28 (48% patients, mostly mild effects (86%. Conclusion: A ten day treatment with BMTO is an effective and safe strategy to combat confirmed H. pylori infection in patients.

  1. A phase II study of VP-16-ifosfamide-cisplatin combination chemotherapy plus early concurrent thoracic irradiation for previously untreated limited small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Woo, In Sook; Park, Young Suk; Kwon, Sung Hee [Hallym Univ., Seoul (Korea, Republic of). Coll. of Medicine] [and others

    2000-12-01

    At present the addition of thoracic irradiation to combination chemotherapy is a standard treatment for limited staged small cell ling cancer. However, there is still controversy about the optimum timing of chest irradiation. We conducted a phase II study of etoposide (VP-16)-ifosfamide-cisplatin (VIP) combination chemotherapy plus early concurrent thoracic irradiation for the patients with previously untreated limited small cell lung cancer in order to assess if the treatment modality could improve the response rate and the toxicity. Forty-four patients with limited small cell lung cancer were treated with etoposide-ifosfamide-cisplatin and concurrent thoracic irradiation. Combination chemotherapy consisted of etoposide 100 mg/m{sup 2} (on day 1-3), ifosfamide 1000 mg/m{sup 2} (on days 1 and 2) and cisplatin 100 mg/m{sup 2} (on day 1). Concurrent thoracic irradiation consisted of a total of 4000 cGy over 4 weeks starting on the first day of the first chemotherapy. All patients who showed a complete response were given prophylactic cranial irradiation for 2.5 weeks. Forty-four of the 49 patients who entered the study from May 1994 to August 1998 were evaluable. The median age was 59 years and 40 patients had a performance status of 0 or 1. The median survival time was 22.5 months. Twenty-eight patients (62%) showed a complete response and 16 (38%) a partial response. Twenty-four patients (54%) developed grade 3 or 4 neutropenia; there was a 9% RTOG score 3 or 4 esophagitis. VIP combination chemotherapy and early concurrent thoracic irradiation for patients with limited stage small cell lung cancer revealed excellent antitumor response with tolerable toxicity. (author)

  2. Studies of cellulose binding by cellobiose dehydrogenase and a comparison with cellobiohydrolase 1.

    Science.gov (United States)

    Henriksson, G; Salumets, A; Divne, C; Pettersson, G

    1997-01-01

    The binding isotherm to cellulose of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium has been compared with that of cellobiohydrolase 1 (CBH 1) from Trichoderma reesei. CDH binds more strongly but more sparsely to cellulose than does CBH 1. In a classical Scatchard analysis, a better fit to a one-site binding model was obtained for CDH than for CBH 1. The binding of both enzymes decreased in the presence of ethylene glycol, increased in the presence of ammonium sulphate and was unaffected by sodium chloride. Attempts to localize the cellulose-binding site on CDH have also been made by exposing enzymically digested CDH to cellulose and isolating the cellulose-bound peptides. The results suggest that the cellulose-binding site is located internally in the amino acid sequence of CDH. PMID:9210407

  3. Marine natural products acting on the acetylcholine-binding protein and nicotinic receptors: from computer modeling to binding studies and electrophysiology.

    Science.gov (United States)

    Kudryavtsev, Denis; Makarieva, Tatyana; Utkina, Natalia; Santalova, Elena; Kryukova, Elena; Methfessel, Christoph; Tsetlin, Victor; Stonik, Valentin; Kasheverov, Igor

    2014-03-28

    For a small library of natural products from marine sponges and ascidians, in silico docking to the Lymnaea stagnalis acetylcholine-binding protein (AChBP), a model for the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), was carried out and the possibility of complex formation was revealed. It was further experimentally confirmed via competition with radioiodinated α-bungarotoxin ([¹²⁵I]-αBgt) for binding to AChBP of the majority of analyzed compounds. Alkaloids pibocin, varacin and makaluvamines С and G had relatively high affinities (K(i) 0.5-1.3 μM). With the muscle-type nAChR from Torpedo californica ray and human neuronal α7 nAChR, heterologously expressed in the GH4C1 cell line, no competition with [¹²⁵I]-αBgt was detected in four compounds, while the rest showed an inhibition. Makaluvamines (K(i) ~ 1.5 μM) were the most active compounds, but only makaluvamine G and crambescidine 359 revealed a weak selectivity towards muscle-type nAChR. Rhizochalin, aglycone of rhizochalin, pibocin, makaluvamine G, monanchocidin, crambescidine 359 and aaptamine showed inhibitory activities in electrophysiology experiments on the mouse muscle and human α7 nAChRs, expressed in Xenopus laevis oocytes. Thus, our results confirm the utility of the modeling studies on AChBPs in a search for natural compounds with cholinergic activity and demonstrate the presence of the latter in the analyzed marine biological sources.

  4. Marine Natural Products Acting on the Acetylcholine-Binding Protein and Nicotinic Receptors: From Computer Modeling to Binding Studies and Electrophysiology

    Directory of Open Access Journals (Sweden)

    Denis Kudryavtsev

    2014-03-01

    Full Text Available For a small library of natural products from marine sponges and ascidians, in silico docking to the Lymnaea stagnalis acetylcholine-binding protein (AChBP, a model for the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs, was carried out and the possibility of complex formation was revealed. It was further experimentally confirmed via competition with radioiodinated α-bungarotoxin ([125I]-αBgt for binding to AChBP of the majority of analyzed compounds. Alkaloids pibocin, varacin and makaluvamines С and G had relatively high affinities (Ki 0.5–1.3 μM. With the muscle-type nAChR from Torpedo californica ray and human neuronal α7 nAChR, heterologously expressed in the GH4C1 cell line, no competition with [125I]-αBgt was detected in four compounds, while the rest showed an inhibition. Makaluvamines (Ki ~ 1.5 μM were the most active compounds, but only makaluvamine G and crambescidine 359 revealed a weak selectivity towards muscle-type nAChR. Rhizochalin, aglycone of rhizochalin, pibocin, makaluvamine G, monanchocidin, crambescidine 359 and aaptamine showed inhibitory activities in electrophysiology experiments on the mouse muscle and human α7 nAChRs, expressed in Xenopus laevis oocytes. Thus, our results confirm the utility of the modeling studies on AChBPs in a search for natural compounds with cholinergic activity and demonstrate the presence of the latter in the analyzed marine biological sources.

  5. Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis

    DEFF Research Database (Denmark)

    Bro, S; Rasmussen, R A; Handberg, J

    1998-01-01

    The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main...... calcium concentration of 1.25 mmol/L and a fixed alfacalcidol dose for at least 2 months. All had previously tolerated therapy with calcium carbonate. Of the 19 patients included, 10 completed both treatment arms. After 12 weeks of therapy, the mean (+/-SEM) plasma ionized calcium level was significantly...... lower in the ketoglutarate arm compared with the calcium carbonate arm (4.8+/-0.1 mg/dL v 5.2+/-0.1 mg/dL; P = 0.004), whereas the mean plasma phosphate (4.5+/-0.3 mg/dL v 5.1+/-0.1 mg/dL) and PTH levels (266+/-125 pg/mL v 301+/-148 pg/mL) did not differ significantly between the two treatment arms...

  6. Phase I/II study of gefitinib (Iressa(®)) and vorinostat (IVORI) in previously treated patients with advanced non-small cell lung cancer.

    Science.gov (United States)

    Han, Ji-Youn; Lee, Soo Hyun; Lee, Geon Kook; Yun, Tak; Lee, Young Joo; Hwang, Kum Hui; Kim, Jin Young; Kim, Heung Tae

    2015-03-01

    Vorinostat has been shown to overcome resistance to gefitinib. We performed a phase I/II study combining gefitinib with vorinostat in previously treated non-small cell lung cancer (NSCLC). A 3 + 3 dose-escalation design was used to determine maximum tolerated dose (MTD) and recommended phase II dose (RP2D). Three dose levels were tested: 250 mg/day gefitinib on days 1-28 and 200, 300 or 400 mg/day vorinostat on days 1-7, and 15-21 out of every 28 days. The primary endpoint was median progression-free survival (PFS). Fifty-two patients were enrolled and treated (43 in phase II). The median age was 59 years, 28 patients were male, 44 had adenocarcinoma, 29 had never smoked, and 36 had undergone one prior treatment. Twenty-two patients exhibited sensitive EGFR mutations. Planned dose escalation was completed without reaching the MTD. The RP2D was 250 mg gefitinib and 400 mg vorinostat. In 43 assessable patients in phase II, the median PFS was 3.2 months; the overall survival (OS) was 19.0 months. There were 16 partial responses and six cases of stable disease. In EGFR-mutant NSCLC, response rate was 77 %, median PFS was 9.1 months, and median OS was 24.1 months. The most common adverse events were anorexia and diarrhea. Treatment with 250 mg gefitinib daily with biweekly 400 mg/day vorinostat was feasible and well tolerated. In an unselected patient population, this combination dose did not improve PFS. However, this combination showed a potential for improving efficacy of gefitinib in EGFR-mutant NSCLC (NCT01027676).

  7. Binding between bixin and whey protein at pH 7.4 studied by spectroscopy and isothermal titration calorimetry.

    Science.gov (United States)

    Zhang, Yue; Zhong, Qixin

    2012-02-22

    Bixin is the major coloring component of annatto used in manufacturing colored cheeses, but its presence in liquid whey causes undesirable quality of the recovered whey protein ingredients. The objective of this work was to study molecular binding between bixin and three major whey proteins (β-lactoglobulin, α-lactalbumin, and bovine serum albumin) at pH 7.4 using UV-vis absorption spectroscopy, fluorescence spectroscopy, isothermal titration calorimetry, and circular dichroism. These complementary techniques illustrated that the binding is a spontaneous complexation process mainly driven by hydrophobic interactions. The complexation is favored at a lower temperature and a higher ionic strength. At a lower temperature, the binding is entropy-driven, while it changes to an enthalpy-driven process at higher temperatures. The binding also increases the percentage of unordered secondary structures of proteins. Findings from this work can be used to develop whey protein recovery processes for minimizing residual annatto content in whey protein ingredients.

  8. Spectroscopic studies on the binding interaction of phenothiazinium dyes, azure A and azure B to double stranded RNA polynucleotides

    Science.gov (United States)

    Khan, Asma Yasmeen; Suresh Kumar, Gopinatha

    2016-01-01

    This manuscript presents spectroscopic characterization of the interaction of two phenothiazinium dyes, azure A and azure B with double stranded (ds) ribonucleic acids, poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C). Absorbance and fluorescence studies revealed that these dyes bind to the RNAs with binding affinities of the order 106 M-1 to poly(A).poly(U), and 105 M-1 to poly(C).poly(G) and poly(I).poly(C), respectively. Fluorescence quenching and viscosity data gave conclusive evidence for the intercalation of the dyes to these RNA duplexes. Circular dichroism results suggested that the conformation of the RNAs was perturbed on interaction and the dyes acquired strong induced optical activity on binding. Azure B bound to all the three RNAs stronger than azure A and the binding affinity varied as poly(A).poly(U) > poly(C).poly(G) > poly(I).poly(C) for both dyes.

  9. Effect of donepezil in patients with Alzheimer's disease previously untreated or treated with memantine or nootropic agents in Germany: an observational study.

    Science.gov (United States)

    Klinger, Tatjana; Ibach, Bernd; Schoenknecht, Peter; Kamleiter, Martin; Silver, Gabrielle; Schroeder, Johannes; Mielke, Ruediger

    2005-05-01

    This open-label, prospective, observational, Post-Marketing Surveillance (PMS) study assessed the efficacy and safety of donepezil in patients who had been switched from therapies currently used in Germany to treat Alzheimer's disease (AD), such as memantine and nootropics, due to insufficient efficacy or poor tolerability. A treatment-naive population was included as a comparator. Patients with AD were treated with donepezil and observed for a period of approximately 3 months. A cognitive assessment was made using the Mini-Mental State Examination (MMSE). Quality of life (QoL) was assessed by the investigators who answered the question 'How did therapy with donepezil influence the QoL of the patient and/or his family over the observation period?' and was graded using three ratings: improved/unchanged/worsened. Adverse events (AEs) were also monitored. A total of 913 patients entered the study (mean +/- SD MMSE score 18.03 +/- 5.34). Efficacy assessments were analyzed for three groups: an overall group of patients who had received any form of prior AD drug therapy (N+ group; n = 709); a subgroup of patients from the N+ group who had received prior memantine therapy only (M+ group; n = 111) and patients who were drug treatment naive (N- group; n = 204). In the evaluable population donepezil improved MMSE scores by 2.21 +/- 3.47 points on average, with similar improvements observed in all three groups. QoL was judged to be improved in at least 70% of patients, again with similar results obtained for all three groups. Donepezil was well tolerated, with 85 of 913 (9.3%) patients reporting AEs. The most common AEs were those typically seen with cholinergic therapies (i.e., diarrhoea, vomiting and nausea). In this observational PMS study, donepezil was shown to be efficacious and well tolerated in patients who were being insufficiently treated with memantine or nootropic therapy. The magnitude of response was similar to that observed in patients who were previously

  10. Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis.

    Science.gov (United States)

    Bhakhoa, Hanusha; Rhyman, Lydia; Lee, Edmond P F; Ramasami, Ponnadurai; Dyke, John M

    2016-03-18

    Can cyclen (1,4,7,10-tetraazacyclododecane) bind alkali metal azides? This question is addressed by studying the geometric and electronic structures of the alkali metal azide-cyclen [M(cyclen)N3] complexes using density functional theory (DFT). The effects of adding a second cyclen ring to form the sandwich alkali metal azide-cyclen [M(cyclen)2N3] complexes are also investigated. N3(-) is found to bind to a M(+) (cyclen) template to give both end-on and side-on structures. In the end-on structures, the terminal nitrogen atom of the azide group (N1) bonds to the metal as well as to a hydrogen atom of the cyclen ring through a hydrogen bond in an end-on configuration to the cyclen ring. In the side-on structures, the N3 unit is bonded (in a side-on configuration to the cyclen ring) to the metal through the terminal nitrogen atom of the azide group (N1), and through the other terminal nitrogen atom (N3) of the azide group by a hydrogen bond to a hydrogen atom of the cyclen ring. For all the alkali metals, the N3-side-on structure is lowest in energy. Addition of a second cyclen unit to [M(cyclen)N3] to form the sandwich compounds [M(cyclen)2N3] causes the bond strength between the metal and the N3 unit to decrease. It is hoped that this computational study will be a precursor to the synthesis and experimental study of these new macrocyclic compounds; structural parameters and infrared spectra were computed, which will assist future experimental work. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Binding of Cu(II) ions to peptides studied by fluorescence spectroscopy and isothermal titration calorimetry

    Science.gov (United States)

    Makowska, Joanna; Żamojć, Krzysztof; Wyrzykowski, Dariusz; Uber, Dorota; Wierzbicka, Małgorzata; Wiczk, Wiesław; Chmurzyński, Lech

    2016-01-01

    Steady-state and time-resolved fluorescence quenching measurements supported by Isothermal Titration Calorimetry (ITC) were used to study the interactions of Cu2 + with four peptides. Two of them were taken from the N-terminal part of the FBP28 protein (formin binding protein) WW domain: Tyr-Lys-Thr-Ala-Asp-Gly-Lys-Thr-Tyr-NH2 (D9) and its mutant Tyr-Lys-Thr-Ala-Asn-Gly-Lys-Thr-Tyr-NH2 (D9_M) as well as two mutated peptides from the B3 domain of the immunoglobulin binding protein G derived from Streptococcus: Asp-Val-Ala-Thr-Tyr-Thr-NH2 (J1) and Glu-Val-Ala-Thr-Tyr-Thr-NH2 (J2). The measurements were carried out at 298.15 K in 20 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer solution with a pH of 6. The fluorescence of all peptides was quenched by Cu2 + ions. The stoichiometry, conditional stability constants and thermodynamic parameters for the interactions of the Cu2 + ions with D9 and D9_M were determined from the calorimetric data. The values of the conditional stability constants were additionally determined from fluorescence quenching measurements and compared with those obtained from calorimetric studies. There was a good correlation between data obtained from the two techniques. On the other hand, the studies revealed that J1 and J2 do not exhibit an affinity towards metal ions. The obtained results prove that fluorescence quenching experiments may be successfully used in order to determine stability constants of complexes with fluorescent ligands. Finally, based on the obtained results, the coordinating properties of the peptides towards the Cu2 + ions are discussed.

  12. Experimental and molecular docking studies on DNA binding interaction of adefovir dipivoxil: Advances toward treatment of hepatitis B virus infections

    Science.gov (United States)

    Shahabadi, Nahid; Falsafi, Monireh

    The toxic interaction of adefovir dipivoxil with calf thymus DNA (CT-DNA) was investigated in vitro under simulated physiological conditions by multi-spectroscopic techniques and molecular modeling study. The fluorescence spectroscopy and UV absorption spectroscopy indicated drug interacted with CT-DNA in a groove binding mode. The binding constant of UV-visible and the number of binding sites were 3.33 ± 0.2 × 104 L mol-1and 0.99, respectively. The fluorimetric studies showed that the reaction between the drug and CT-DNA is exothermic (ΔH = 34.4 kJ mol-1; ΔS = 184.32 J mol-1 K-1). Circular dichroism spectroscopy (CD) was employed to measure the conformational change of CT-DNA in the presence of adefovir dipivoxil, which verified the groove binding mode. Furthermore, the drug induces detectable changes in its viscosity. The molecular modeling results illustrated that adefovir strongly binds to groove of DNA by relative binding energy of docked structure -16.83 kJ mol-1. This combination of multiple spectroscopic techniques and molecular modeling methods can be widely used in the investigation on the toxic interaction of small molecular pollutants and drugs with bio macromolecules, which contributes to clarify the molecular mechanism of toxicity or side effect in vivo.

  13. Effects of Local Protein Environment on the Binding of Diatomic Molecules to Heme in Myoglobins. DFT and Dispersion-Corrected DFT Studies

    Science.gov (United States)

    Liao, Meng-Sheng; Huang, Ming-Ju; Watts, John D.

    2013-01-01

    The heme-AB binding energies (AB = CO, O2) in a wild-type myoglobin (Mb) and two mutants (H64L, V68N) of Mb have been investigated in detail with both DFT and dispersioncorrected DFT methods, where H64L and V68N represent two different, opposite situations. Several dispersion correction approaches were tested in the calculations. The effects of the local protein environment were accounted for by including the five nearest surrounding residues in the calculated systems. The specific role of histidine-64 in the distal pocket was examined in more detail in this study than in other studies in the literature. Although the present calculated results do not change the previous conclusion that the hydrogen bonding by the distal histidine-64 residue plays a major role in the O2/CO discrimination by Mb, more details about the interaction between the protein environment and the bound ligand have been revealed in this study by comparing the binding energies of AB to a porphyrin and the various myoglobins. The changes in the experimental binding energies from one system to another are well reproduced by the calculations. Without constraints on the residues in geometry optimization, the dispersion correction is necessary, since it improves the calculated structures and energetic results significantly. PMID:23661270

  14. Thermodynamic Studies of Cu(I) and Other d10 Metal Ions Binding to Proteins in the Copper Homeostasis Pathway and the Organomercurial Detoxification Pathway

    Science.gov (United States)

    Stevenson, Michael James

    Copper(I) is the predominant oxidation state of this essential metal in living cells due to reducing intracellular conditions. Because of deleterious copper-mediated Fenton chemistry, intracellular copper trafficking pathways involve strict regulation by metallochaperone proteins. Previous studies of the 68-residue metallochaperone, HAH1, have shown that it coordinates Cu(I) with two cysteines for transport from Ctr1 in the cell membrane to ATPases in the Golgi network. Using isothermal titration calorimetry (ITC), and methods to suppress oxidation and disproportionation of Cu(I), the thermodynamics of Cu(I), as well as other metal ions, binding to HAH1 have been accurately quantified. During the course of this study, the Cu(I) binding thermodynamics with the stabilizing ligand hexamethyltrien were determined in order to accurately quantify the Cu(I) binding thermodynamics with proteins, and revealed an unexpected Cu(I) coordination chemistry with this ligand. In addition, HAH1 binding the Cu(I) analogue Ag(I), the abundant cellular metal ion Zn(II), and the thiophilic toxic metal ion Hg(II), have been quantified. The binding thermodynamics of these metal ions were also determined in the presence of glutathione to more accurately model physiological conditions. HAH1 has a high affinity for Cu(I), which is both enthalpically and entropically favorable. It has a substantially lower affinity for Zn(II), which is entropically favored, suggesting that Zn(II) is not able to compete with Cu(I) for HAH1 in vivo. However, HAH1 has an exceptionally high affinity for Hg(II), with its larger thiophilicity, and it will displace Cu(I). Mercury(II) and particularly organomercurial compounds are very toxic, yet proteins from the bacterial mer operon provide resistance to this toxicity. In particular, the organomercurial lyase MerB, whose only known structural homologue is a putative copper metallochaperone, is responsible for cleavage of the carbon-mercury bond of MeHg(II) and

  15. Binding and Irradition Study of the Porphyrin-Protein Complex TSPP-HSA

    Science.gov (United States)

    Palos-Chavez, Jorge

    2013-04-01

    Porphyrins are a class of organic molecules that have found numerous applications in biological physics, such as, for example, photodynamic therapy in the treatment of malignant tumors and serving as fluorescent tags for proteins. In this study, we focus on the porphyryn TSPP and its role as a photoactive ligand to the protein HSA (Human Serum Albumin), capable of mediating conformational changes to the structure of HSA via irradiation. The effect of irradiation on the conformation and binding behavior of HSA in buffer solution at physiological pH will be deduced from a combination of spectroscopy tools including absorption, fluorescence, circular dichroism, and fluorescence lifetime decay spectroscopy. Additionally, computational modeling will be employed to complement experimental data. This work was supported through the grant TWD MARC GM07717.

  16. Binding site of ribosomal proteins on prokaryotic 5S ribonucleic acids: a study with ribonucleases

    DEFF Research Database (Denmark)

    Douthwaite, S; Christensen, A; Garrett, R A

    1982-01-01

    ., & Garrett, R. A. (1981) Biochemistry 20, 7301--7307], reveal an extensive interaction site for protein L18 and a more localized one for L25. Generally comparable results, with a few important differences, were obtained in a study of the binding sites of the two E. coli proteins on Bacillus...... stearothermophilus 5S RNA. Several protein-induced changes in the RNA structures were identified; some are possibly allosteric in nature. The two prokaryotic 5S RNAs were also incubated with total 50S subunit proteins from E. coli and B. stearothermophilus ribosomes. Homologous and heterologous reconstitution...... experiments were performed for both RNAs. The effects of the bound proteins on the ribonuclease digestion of the RNAs could generally be correlated with the results obtained with the E. coli proteins L18 and L25, although there was evidence for an additional protein-induced conformational change in the B...

  17. A longitudinal study of serum cobalamins and its binding proteins in lactating women

    DEFF Research Database (Denmark)

    Mørkbak, A L; Ramlau-Hansen, C H; Møller, U K

    2006-01-01

    OBJECTIVE: To examine longitudinal changes in serum cobalamins, transcobalamin (TC) and haptocorrin (HC) during lactation and to investigate the influence of vitamin B12 supplementation on these parameters. DESIGN: A 9-month follow-up study. SUBJECTS AND METHODS: Lactating mothers (N=89) including...... 23 supplemented with vitamin B12 (1-18 microg/daily), 41 partly supplemented and 25 not supplemented. Blood samples collected 3 weeks (baseline) and 4 and 9 months post-partum were analysed for cobalamins, TC and HC. Both the total concentration and the cobalamin-saturated form (holo) of TC and HC...... were analysed. RESULTS: No significant differences were observed in serum cobalamins or its binding proteins related to supplementation with vitamin B12 or the duration of lactation. Serum cobalamins remained unchanged from 3 weeks to 9 months post-partum. Total TC (holoTC) (median+/-s.e. pmol...

  18. Single protein omission reconstitution studies of tetracycline binding to the 30S subunit of Escherichia coli ribosomes

    International Nuclear Information System (INIS)

    Buck, M.; Cooperman, B.S.

    1990-01-01

    In previous work the authors showed that on photolysis of Escherichia coli ribosomes in the presence of [ 3 H]tetracycline (TC) the major protein labeled is S7, and they presented strong evidence that such labeling takes place from a high-affinity site related to the inhibitory action of TC. In this work they use single protein omission reconstitution (SPORE) experiments to identify those proteins that are important for high-affinity TC binding to the 30S subunit, as measured by both cosedimentation and filter binding assays. With respect to both sedimentation coefficients and relative Phe-tRNA Phe binding, the properties of the SPORE particles they obtain parallel very closely those measured earlier, with the exception of the SPORE particle lacking S13. A total of five proteins, S3, S7, S8, S14, and S19, are shown to be important for TC binding, with the largest effects seen on omission of proteins S7 and S14. Determination of the protein compositions of the corresponding SPORE particles demonstrates that the observed effects are, for the most part, directly attributable to the omission of the given protein rather than reflecting an indirect effect of omitting one protein on the uptake of another. A large body of evidence supports the notion that four of these proteins, S3, S7, S14, and S19, are included, along with 16S rRNA bases 920-1,396, in one of the major domains of the 30S subunit. The results support the conclusion that the structure of this domain is important for the binding of TC and that, within this domain, TC binds directly to S7

  19. Lysine-functionalized nanodiamonds: synthesis, physiochemical characterization, and nucleic acid binding studies

    Directory of Open Access Journals (Sweden)

    Kaur R

    2012-07-01

    . These modified NDs formed highly stable aqueous dispersions with a zeta potential of 49 mV and particle size of approximately 20 nm. The functionalized NDs were found to be able to bind plasmid DNA and small interfering RNA by forming nanosized "diamoplexes".Conclusion: The lysine-substituted ND particles generated in this study exhibit stable aqueous formulations and show potential for use as carriers for genetic materials.Keywords: disaggregation, spectroscopy, dispersion, electrophoresis, size, zeta potential

  20. Phase I study of cisplatin, hyperthermia, and lapatinib in patients with recurrent carcinoma of the uterine cervix in a previously irradiated area

    NARCIS (Netherlands)

    E.V. Meerten (Esther Van); M. Franckena (Martine); E.A.C. Wiemer (Erik); L.V. Doorn (Lena Van); J. Kraan (Jaco); A.M. Westermann (Anneke); S. Sleijfer (Stefan)

    2015-01-01

    textabstractBackground. Patients with recurrent cervical cancer in a previously irradiated area might benefit from cisplatin combined with hyperthermia. Lapatinib inhibits the intracellular tyrosine kinase domain of the epidermal growth factor receptor (EGFR) and HER2. Overexpression of EGFR and

  1. Phase I study of cisplatin, hyperthermia, and lapatinib in patients with recurrent carcinoma of the uterine cervix in a previously irradiated area

    NARCIS (Netherlands)

    van Meerten, Esther; Franckena, Martine; Wiemer, Erik; van Doorn, Lena; Kraan, Jaco; Westermann, Anneke; Sleijfer, Stefan

    2015-01-01

    Patients with recurrent cervical cancer in a previously irradiated area might benefit from cisplatin combined with hyperthermia. Lapatinib inhibits the intracellular tyrosine kinase domain of the epidermal growth factor receptor (EGFR) and HER2. Overexpression of EGFR and HER2 is frequently seen in

  2. Synthesis, DNA-binding and photocleavage studies of Ru(II ...

    Indian Academy of Sciences (India)

    Administrator

    ligands to evaluate and understand the factors that determine the DNA-binding mode are necessary. Thus it is ... further understanding the DNA-binding and effi- ciency of DNA recognized and cleaved by Ru(II) complexes .... Titration experiments were performed by using a fixed Ru(II) complex concentration, The complex-.

  3. A Comparison Study for DNA Motif Modeling on Protein Binding Microarray

    KAUST Repository

    Wong, Ka-Chun

    2015-06-11

    Transcription Factor Binding Sites (TFBSs) are relatively short (5-15 bp) and degenerate. Identifying them is a computationally challenging task. In particular, Protein Binding Microarray (PBM) is a high-throughput platform that can measure the DNA binding preference of a protein in a comprehensive and unbiased manner; for instance, a typical PBM experiment can measure binding signal intensities of a protein to all possible DNA k-mers (k=810). Since proteins can often bind to DNA with different binding intensities, one of the major challenges is to build motif models which can fully capture the quantitative binding affinity data. To learn DNA motif models from the non-convex objective function landscape, several optimization methods are compared and applied to the PBM motif model building problem. In particular, representative methods from different optimization paradigms have been chosen for modeling performance comparison on hundreds of PBM datasets. The results suggest that the multimodal optimization methods are very effective for capturing the binding preference information from PBM data. In particular, we observe a general performance improvement using di-nucleotide modeling over mono-nucleotide modeling. In addition, the models learned by the best-performing method are applied to two independent applications: PBM probe rotation testing and ChIP-Seq peak sequence prediction, demonstrating its biological applicability.

  4. Spectroscopic and molecular docking studies of binding interaction of gefitinib, lapatinib and sunitinib with bovine serum albumin (BSA).

    Science.gov (United States)

    Shen, Guo-Feng; Liu, Ting-Ting; Wang, Qi; Jiang, Min; Shi, Jie-Hua

    2015-12-01

    The binding interactions of three kinds of tyrosine kinase inhibitors (TKIs), such as gefitinib, lapatinib and sunitinib, with bovine serum albumin (BSA) were studied using ultraviolet spectrophotometry, fluorescence spectroscopy, circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and molecular docking methods. The experimental results showed that the intrinsic fluorescence quenching of BSA induced by the three TKIs resulted from the formation of stable TKIs-BSA complexes through the binding interaction of TKIs with BSA. The stoichiometry of three stable TKIs-BSA complexes was 1:1 and the binding constants (Kb) of the three TKIs-BSA complexes were in the order of 10(4)M(-1) at 310 K, indicating that there was a strong binding interaction of the three TKIs with BSA. Based on the analysis of the signs and magnitudes of the free energy change (ΔG(0)), enthalpic change (ΔH(0)) and entropic change (ΔS(0)) in the binding process, it can be deduced that the binding process of the three TKIs with BSA was spontaneous and enthalpy-driven process, and the main interaction forces between the three TKIs and BSA were van der Waals force and hydrogen bonding interaction. Moreover, from the results of CD, FT-IR and molecular docking, it can be concluded that there was a significant difference between the three TKIs in the binding site on BSA, lapatinib was located on site II (m) of BSA while gefitinib and sunitinib were bound on site I of BSA, and there were some changes in the BSA conformation when binding three TKIs to BSA but BSA still retains its secondary structure α-helicity. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Clinical evaluation of recombinant factor VIII preparation (Kogenate) in previously treated patients with hemophilia A: descriptive meta-analysis of post-marketing study data.

    Science.gov (United States)

    Yoshioka, A; Fukutake, K; Takamatsu, J; Shirahata, A

    2006-08-01

    The safety and efficacy of Kogenate, a recombinant factor VIII (rFVIII) preparation for the treatment of bleeding episodes, were studied in a 123-patient meta-analysis population of previously treated patients (PTPs), including 15 enrolled in the registration Phase III trial (PTP-I group), 93 from the post-marketing special investigation (PTP-II group), and 15 from short-term special investigations in surgery or tooth extraction (SI group). These patients (82 severe, 31 moderate, 9 mild, and 1 unknown), aged 11 months to 72 years, were enrolled in 28 centers in Japan. Blood samples taken at the baseline and at 3, 6, 9, 12, 18, and 24 months after the introduction of Kogenate were evaluated for FVIII inhibitor antibodies, antibodies formed against trace proteins derived from the rFVIII production process, and for general changes in laboratory test results. Mean exposure to Kogenate was 1103 days in PTP-I, 86 days in PTP-II, 27 days in patients in surgery, and 2 days in patients with tooth extraction. Assessment of FVIII inhibitor activity was conducted in 115 of the 123 patients by means of the Bethesda assay. Twelve patients were found to have a low titer of FVIII inhibitor (0.5-3.0 BU/mL) prior to any administration of Kogenate, and 103 were inhibitor-negative at the baseline. Among this latter group, 3 patients (2.9%) tested inhibitor-positive, with titers ranging from 1.2 to 2.1 BU/mL, with 4 patients below 1.0 BU/mL. One patient in the 11 PTPs investigated (PTP-I) developed antibodies against baby hamster kidney protein and mouse immunoglobulin G, but these findings were transient and asymptomatic. Hemostasis was achieved (markedly effective or effective) in 3666 of the 3855 bleeding episodes (95.1%) observed in 108 patients. Only 1 infusion was necessary in 3790 (98.3%) of these episodes. These data indicate that Kogenate is safe and very effective for the treatment of bleeding in PTPs with hemophilia A.

  6. Synthesis, DNA binding, photo-induced DNA cleavage, cytotoxicity studies of a family of heavy rare earth complexes.

    Science.gov (United States)

    Chen, Gong-Jun; Wang, Zhi-Gang; Qiao, Xin; Xu, Jing-Yuan; Tian, Jin-Lei; Yan, Shi-Ping

    2013-10-01

    As a continuing investigation of our previous studies about the influence of the different rare earth metal ions on the bioactivity, a family of heavy rare earth metal complexes, [RE(acac)3(dpq)] (RE=Tb (1), Dy (2), Ho (3), Er (4), Tm (5), Yb (6), Lu (7)) and [RE(acac)3(dppz)]·CH3OH (RE=Tb (8), Dy (9), Ho (10), Er (11), Tm (12), Yb (13), Lu (14) viz. acetylacetonate (acac), dipyrido[3,2-d:20,30-f]quinoxaline (dpq), dipyrido[3,2-a:20,30-c] phenazine (dppz)), has been synthesized and their biological activities were also investigated. On the irradiation with UV-A light of 365nm or ambient light, all complexes exhibit efficient DNA cleavage activity via the mechanistic pathway involving the formation of singlet oxygen and hydroxyl radical as the reactive species. In addition, the in vitro cytotoxicity of these complexes on HeLa cells has been examined by MTT assay, which indicate that these compounds have the potential to act as effective anticancer drugs. The results of the above biological experiments also reveal that the choice of different rare earth metal ions has little influence on the DNA binding, DNA cleavage and cytotoxicity. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Multispectroscopic studies of paeoniflorin binding to calf thymus DNA in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guowen, E-mail: gwzhang@ncu.edu.cn [State Key Laboratory of Food Science and Technology, Nanchang University, No. 235, Nanjing East Road, Nanchang, Jiangxi 330047 (China); Fu, Peng; Pan, Junhui [State Key Laboratory of Food Science and Technology, Nanchang University, No. 235, Nanjing East Road, Nanchang, Jiangxi 330047 (China)

    2013-02-15

    The mechanism of paeoniflorin binding to calf thymus DNA in physiological buffer (pH 7.4) was investigated by multispectroscopic methods including UV-vis absorption, fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy, coupled with viscosity measurements and DNA melting techniques. The results suggested that paeoniflorin molecules could bind to DNA via groove binding mode as evidenced by no significant change in iodide quenching effect, increase in single-stranded DNA (ssDNA) quenching effect, and almost unchanged relative viscosity and melting temperature of DNA. The observed changes in CD signals revealed that DNA remains in the B-conformation. Further, the displacement experiments with Hoechst 33258 probe and the results of FT-IR spectra indicated that paeoniflorin mainly binds in the region of rich A-T base pairs of DNA. The thermodynamic parameters, enthalpy change ({Delta}H Degree-Sign ) and entropy change ({Delta}S Degree-Sign ) were calculated to be -30.09{+-}0.18 kJ mol{sup -1} and -14.07{+-}0.61 J mol{sup -1} K{sup -1} by the van't Hoff equation, suggesting that hydrogen bond and van der Waals forces play a predominant role in the binding of paeoniflorin to DNA. - Highlights: Black-Right-Pointing-Pointer The binding mode of paeoniflorin to calf thymus DNA is the minor groove binding. Black-Right-Pointing-Pointer Paeoniflorin mainly binds in the region of rich A-T base pairs of DNA. Black-Right-Pointing-Pointer The binding does not alter the native B-conformation of DNA. Black-Right-Pointing-Pointer The binding is driven mainly by hydrogen bonds and van der Waals forces.

  8. Analysis of drug-protein binding using on-line immunoextraction and high-performance affinity microcolumns: Studies with normal and glycated human serum albumin.

    Science.gov (United States)

    Matsuda, Ryan; Jobe, Donald; Beyersdorf, Jared; Hage, David S

    2015-10-16

    A method combining on-line immunoextraction microcolumns with high-performance affinity chromatography (HPAC) was developed and tested for use in examining drug-protein interactions with normal or modified proteins. Normal human serum albumin (HSA) and glycated HSA were used as model proteins for this work. High-performance immunoextraction microcolumns with sizes of 1.0-2.0 cm × 2.1mm i.d. and containing anti-HSA polyclonal antibodies were developed and tested for their ability to bind normal HSA or glycated HSA. These microcolumns were able to extract up to 82-93% for either type of protein at 0.05-0.10 mL/min and had a binding capacity of 0.34-0.42 nmol HSA for a 1.0 cm × 2.1mm i.d. microcolumn. The immunoextraction microcolumns and their adsorbed proteins were tested for use in various approaches for drug binding studies. Frontal analysis was used with the adsorbed HSA/glycated HSA to measure the overall affinities of these proteins for the drugs warfarin and gliclazide, giving comparable values to those obtained previously using similar protein preparations that had been covalently immobilized within HPAC columns. Zonal elution competition studies with gliclazide were next performed to examine the specific interactions of this drug at Sudlow sites I and II of the adsorbed proteins. These results were also comparable to those noted in prior work with covalently immobilized samples of normal HSA or glycated HSA. These experiments indicated that drug-protein binding studies can be carried out by using on-line immunoextraction microcolumns with HPAC. The same method could be used in the future with clinical samples and other drugs or proteins of interest in pharmaceutical studies or biomedical research. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate

    Science.gov (United States)

    Iqbal, Muhammad; Ali, Saqib; Tahir, Muhammad Nawaz; Muhammad, Niaz; Shah, Naseer Ali; Sohail, Manzar; Pandarinathan, Vedapriya

    2015-08-01

    A new binuclear O-bridged Cu(II) complex with 4-chlorophenyl acetate and 2,2‧-bipyridine has been synthesized and characterized using FT-IR, powder and single crystal XRD and electrochemical solution studies. The results revealed that the two penta-coordinated Cu(II) centers are linked by two carboxylate ligands in end-on bonding fashion. The coordination geometry is slightly distorted square pyramidal (SP) with bridging oxygen atoms occupying the apical position and other ligands lying in the equatorial plane. The striking difference in Cu-O bond distance of the bridging oxygen atom in the complex may be responsible for the SP geometry of Cu(II) ion. The complex gave rise to metal centered irreversible electro-activity where one electron Cu(II)/Cu(III) oxidation process and a single step two electron Cu(II)/Cu(0) reduction process was observed. The redox processes were found predominantly adsorption controlled. The values of diffusion coefficient and heterogeneous rate constant for oxidation process were 6.98 × 10-7 cm2 s-1 and 4.60 × 10-5 cm s-1 while the corresponding values for reduction were 5.30 × 10-8 cm2 s-1 and 5.41 × 10-6 cm s-1, respectively. The formal potential and charge transfer coefficient were also calculated. The DNA-binding ability was explored through cyclic voltammetry and UV-Visible spectroscopy. Diminution in the value of Do for oxidation indicated the binding of the complex with DNA corresponding to Kb = 8.58 × 104 M-1. UV-Visible spectroscopy yielded ε = 49 L mol-1 cm-1 and Kb = 2.96 × 104 M-1. The data of both techniques support each other. The self-induced redox activation of the complex, as indicated by cyclic voltammetry heralds its potential applications in redox catalysis and anticancer activity.

  10. Effects of epilepsy and selected antiepileptic drugs on risk of myocardial infarction, stroke, and death in patients with or without previous stroke: a nationwide cohort study

    DEFF Research Database (Denmark)

    Olesen, J. B.; Abildstrom, S. Z.; Erdal, Jesper

    2011-01-01

    Purpose Patients with epilepsy have increased morbidity and mortality. We evaluated the risk of myocardial infarction (MI), stroke, and death associated with epilepsy and examined if this risk was modified by treatment with antiepileptic drugs (AEDs). Methods A cohort consisting of the Danish...... population was followed from January 1997 to December 2006. The risk of MI, stroke, cardiovascular death, and all-cause death associated with epilepsy was estimated by multivariable Cox proportional hazard models stratified for occurrence of previous stroke. AED use was determined at baseline, and risks...... associated with exposure to individual AEDs were examined in patients with epilepsy. Results In patients without previous stroke, AED-treated epilepsy was associated with an increased risk of MI (hazard ratio [HR], 1.09; 95%CI, 1.00-1.19), stroke (HR, 2.22; 95%CI, 2.09-2.36), cardiovascular death (HR, 1...

  11. New insights from molecular dynamic simulation studies of the multiple binding modes of a ligand with G-quadruplex DNA

    Science.gov (United States)

    Hou, Jin-Qiang; Chen, Shuo-Bin; Tan, Jia-Heng; Luo, Hai-Bin; Li, Ding; Gu, Lian-Quan; Huang, Zhi-Shu

    2012-12-01

    G-quadruplexes are higher-order DNA and RNA structures formed from guanine-rich sequences. These structures have recently emerged as a new class of potential molecular targets for anticancer drugs. An understanding of the three-dimensional interactions between small molecular ligands and their G-quadruplex targets in solution is crucial for rational drug design and the effective optimization of G-quadruplex ligands. Thus far, rational ligand design has been focused mainly on the G-quartet platform. It should be noted that small molecules can also bind to loop nucleotides, as observed in crystallography studies. Hence, it would be interesting to elucidate the mechanism underlying how ligands in distinct binding modes influence the flexibility of G-quadruplex. In the present study, based on a crystal structure analysis, the models of a tetra-substituted naphthalene diimide ligand bound to a telomeric G-quadruplex with different modes were built and simulated with a molecular dynamics simulation method. Based on a series of computational analyses, the structures, dynamics, and interactions of ligand-quadruplex complexes were studied. Our results suggest that the binding of the ligand to the loop is viable in aqueous solutions but dependent on the particular arrangement of the loop. The binding of the ligand to the loop enhances the flexibility of the G-quadruplex, while the binding of the ligand simultaneously to both the quartet and the loop diminishes its flexibility. These results add to our understanding of the effect of a ligand with different binding modes on G-quadruplex flexibility. Such an understanding will aid in the rational design of more selective and effective G-quadruplex binding ligands.

  12. A pilot study of the combination of cyclosporin A and interferon alfacon-1 for the treatment of hepatitis C in previous nonresponder patients.

    Science.gov (United States)

    Cotler, Scott J; Morrissey, Mary J; Wiley, Thelma E; Layden, Thomas J; Jensen, Donald M

    2003-04-01

    To evaluate the safety and efficacy of the combination of interferon and cyclosporine for the treatment of hepatitis C in previous nonresponder patients. Preliminary data indicated that adding the immunosuppressive agent cyclosporin A to interferon might improve response rates in patients with hepatitis C. Ten previous virologic nonresponders with genotype 1 infection were included. Treatment consisted of interferon alfacon-1, 15 microg/d, and cyclosporine, 100 mg twice daily, for 4 weeks. The dose of interferon alfacon-1 was then decreased to 15 microg three times weekly, and cyclosporine was reduced to 50 mg twice daily. Therapy was continued for 48 weeks unless viremia persisted at week 24. Three of 10 subjects had an on-treatment virologic response, although one had a breakthrough with recurrent viremia during treatment and two relapsed after therapy was completed. On treatment responders had significantly higher trough cyclosporine levels at week 4 compared with nonresponders (P = 0.025). Serum creatinine levels remained stable, and no patient developed diabetes. Triglyceride levels increased during treatment. Cyclosporine was dose reduced in two patients for hypertension. Selected patients with hepatitis C tolerated therapy, including cyclosporine without severe or irreversible toxicity. Despite an association between higher cyclosporine levels and on-treatment response, the combination of cyclosporine and interferon was ineffective in producing a sustained response in previous nonresponder patients.

  13. Radiolabelling of phoneutria nigriventer spider toxin (Tx1): a tool to study its binding site

    International Nuclear Information System (INIS)

    Santos, Raquel Gouvea dos; Diniz, Carlos Roberto; Nascimento, Marta Cordeiro; Lima, Maria Elena de

    1996-01-01

    The neurotoxin Tx1, isolated from the venom of the South American spider Phoneutria nigriventer produces tail elevation and spastic paralysis of posterior limbs after intracerebral ventricular injection in mice. Tx1 also produces ileum contraction in bioassay. We have investigated the binding of radioiodinated-Tx1 ( 125 I-Tx1) on the preparation of myenteric plexus-longitudinal muscle membrane from guinea pig ileum (MPLM) as a tool to characterize the interaction of this neurotoxin with its site. The neurotoxin Tx1 was radioiodinated with Na 125 I by the lactoperoxidase method. 125 I-Tx1 specifically binds to a single class of noninteracting binding sites of high affinity (Kd= 3.5 x 10 -10 M) and low capacity (1.2 pmol/mg protein). The specific binding increased in parallel with the protein concentration. In competition experiments the ligands of ionic channels used (sodium, potassium and calcium) did not affect the binding of 125 I-Tx1 to MPLM neither did the cholinergic ligands (hemicholinium-3, hexamethonium, d-tubocurarine and atropine). Another neurotoxin (Tx2-6, one of the isoforms of Tx2 pool) decreased toxin with MPLM and showed that toxin has a specific and saturable binding site in guinea pig ileum and this binding site appears to be related to the Tx2 site. (author)

  14. A microcalorimetry and binding study on interaction of dodecyl trimethylammonium bromide with wigeon hemoglobin

    International Nuclear Information System (INIS)

    Bordbar, A.K.; Moosavi-Movahedi, A.A.; Amini, M.K.

    2003-01-01

    The thermodynamic parameters for the binding of dodecyl trimethylammonium bromide (DTAB) with wigeon hemoglobin (Hb) in aqueous solution at various pH and 27 deg. C have been measured by equilibrium dialysis and titration microcalorimetry techniques. The Scatchard plots represent unusual features at neutral and alkaline pH and specific binding at acidic pH. This leads us to analyze the binding data by fitting the data to the Hill equation for multiclasses of binding sites. The best fit was obtained with the equation for one class at acidic pH and two classes at neutral and alkaline pH. The thermodynamic analysis of the binding process shows that the strength of binding at neutral pH is more than these at other pH values. This can be related to the more accessible hydrophobic surface area of wigeon hemoglobin at this pH. The endothermic enthalpy data which was measured by microcalorimetry confirms the binding data analysis and represents the more regular and stable structure of wigeon hemoglobin at neutral pH

  15. Detection of secondary binding sites in proteins using fragment screening.

    Science.gov (United States)

    Ludlow, R Frederick; Verdonk, Marcel L; Saini, Harpreet K; Tickle, Ian J; Jhoti, Harren

    2015-12-29

    Proteins need to be tightly regulated as they control biological processes in most normal cellular functions. The precise mechanisms of regulation are rarely completely understood but can involve binding of endogenous ligands and/or partner proteins at specific locations on a protein that can modulate function. Often, these additional secondary binding sites appear separate to the primary binding site, which, for example for an enzyme, may bind a substrate. In previous work, we have uncovered several examples in which secondary binding sites were discovered on proteins using fragment screening approaches. In each case, we were able to establish that the newly identified secondary binding site was biologically relevant as it was able to modulate function by the binding of a small molecule. In this study, we investigate how often secondary binding sites are located on proteins by analyzing 24 protein targets for which we have performed a fragment screen using X-ray crystallography. Our analysis shows that, surprisingly, the majority of proteins contain secondary binding sites based on their ability to bind fragments. Furthermore, sequence analysis of these previously unknown sites indicate high conservation, which suggests that they may have a biological function, perhaps via an allosteric mechanism. Comparing the physicochemical properties of the secondary sites with known primary ligand binding sites also shows broad similarities indicating that many of the secondary sites may be druggable in nature with small molecules that could provide new opportunities to modulate potential therapeutic targets.

  16. Mobility of TOAC spin-labelled peptides binding to the Src SH3 domain studied by paramagnetic NMR

    International Nuclear Information System (INIS)

    Lindfors, Hanna E.; Koning, Peter E. de; Wouter Drijfhout, Jan; Venezia, Brigida; Ubbink, Marcellus

    2008-01-01

    Paramagnetic relaxation enhancement provides a tool for studying the dynamics as well as the structure of macromolecular complexes. The application of side-chain coupled spin-labels is limited by the mobility of the free radical. The cyclic, rigid amino acid spin-label TOAC (2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid), which can be incorporated straightforwardly by peptide synthesis, provides an attractive alternative. In this study, TOAC was incorporated into a peptide derived from focal adhesion kinase (FAK), and the interaction of the peptide with the Src homology 3 (SH3) domain of Src kinase was studied, using paramagnetic NMR. Placing TOAC within the binding motif of the peptide has a considerable effect on the peptide-protein binding, lowering the affinity substantially. When the TOAC is positioned just outside the binding motif, the binding constant remains nearly unaffected. Although the SH3 domain binds weakly and transiently to proline-rich peptides from FAK, the interaction is not very dynamic and the relative position of the spin-label to the protein is well-defined. It is concluded that TOAC can be used to generate reliable paramagnetic NMR restraints

  17. Mobility of TOAC spin-labelled peptides binding to the Src SH3 domain studied by paramagnetic NMR

    Energy Technology Data Exchange (ETDEWEB)

    Lindfors, Hanna E. [Leiden University, Leiden Institute of Chemistry, Gorlaeus Laboratories (Netherlands); Koning, Peter E. de; Wouter Drijfhout, Jan [Leiden University Medical Centre, Department of Immunohematology and Blood Transfusion (Netherlands); Venezia, Brigida; Ubbink, Marcellus [Leiden University, Leiden Institute of Chemistry, Gorlaeus Laboratories (Netherlands)], E-mail: m.ubbink@chem.leidenuniv.nl

    2008-07-15

    Paramagnetic relaxation enhancement provides a tool for studying the dynamics as well as the structure of macromolecular complexes. The application of side-chain coupled spin-labels is limited by the mobility of the free radical. The cyclic, rigid amino acid spin-label TOAC (2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid), which can be incorporated straightforwardly by peptide synthesis, provides an attractive alternative. In this study, TOAC was incorporated into a peptide derived from focal adhesion kinase (FAK), and the interaction of the peptide with the Src homology 3 (SH3) domain of Src kinase was studied, using paramagnetic NMR. Placing TOAC within the binding motif of the peptide has a considerable effect on the peptide-protein binding, lowering the affinity substantially. When the TOAC is positioned just outside the binding motif, the binding constant remains nearly unaffected. Although the SH3 domain binds weakly and transiently to proline-rich peptides from FAK, the interaction is not very dynamic and the relative position of the spin-label to the protein is well-defined. It is concluded that TOAC can be used to generate reliable paramagnetic NMR restraints.

  18. In vitro DNA binding studies of the sweetening agent saccharin and its copper(II) and zinc(II) complexes.

    Science.gov (United States)

    Icsel, Ceyda; Yilmaz, Veysel T

    2014-01-05

    The interactions of fish sperm DNA (FS-DNA) with the sodium salt of sweetener saccharin (sacH) and its copper and zinc complexes, namely [M(sac)2(H2O)4]·2H2O (M=Cu(II) or Zn(II)) were studied by using UV-Vis titration, fluorometric competition, thermal denaturation, viscosity and gel electrophoresis measurements. The intrinsic binding constants (Kb) obtained from absorption titrations were estimated to be 2.86 (±0.06)×10(4)M(-1) for Na(sac), 6.67 (±0.12)×10(4)M(-1) for Cu-sac and 4.01 (±0.08)×10(4)M(-1) for Zn-sac. The Cu-sac complex binds to FS-DNA via intercalation with a KA value of 50.12 (±0.22)×10(4)M(-1) as evidenced by competitive binding studies with ethidium bromide. Moreover, competition experiments with Hoechst 33258 are indicative of a groove binding mode of Na(sac) and Zn-sac with binding constants of 3.13 (±0.16)×10(4)M(-1) and 5.25 (±0.22)×10(4)M(-1), respectively. The spectroscopic measurements indicate a moderate DNA binding affinity of Na(sac) and its metal complexes. The suggested binding modes are further confirmed by the thermal denaturation and viscosity measurements. In addition, Cu-sac and Zn-sac show weak ability to damage to pBR322 supercoiled plasmid DNA. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. DNA binding, DNA cleavage and cytotoxicity studies of a new water soluble copper(II) complex: the effect of ligand shape on the mode of binding.

    Science.gov (United States)

    Kashanian, Soheila; Khodaei, Mohammad Mehdi; Roshanfekr, Hamideh; Shahabadi, Nahid; Mansouri, Ghobad

    2012-02-01

    The interaction of native calf thymus DNA (CT-DNA) with [Cu(ph(2)phen)(phen-dione)Cl]Cl was studied at physiological pH by spectrophotometric, spectrofluorometric, circular dichroism, and viscometric techniques. Considerable hypochromicity and red shift are observed in the UV absorption band of the Cu complex. Binding constants (K(b)) of DNA with the complex were calculated at different temperatures. Thermodynamic parameters, enthalpy and entropy changes were calculated according to Van't Hoff equation, which indicated that reaction is predominantly enthalpically driven. All these results indicate that Cu(II) complex interacts with CT-DNA via intercalative mode. Also, this new complex induced cleavage in pUC18 plasmid DNA as indicated in gel electrophoresis and showed excellent antitumor activity against K562 (human chronic myeloid leukemia) and human T lymphocyte carcinoma-Jurkat cell lines. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Evidence for ProTα-TLR4/MD-2 binding: molecular dynamics and gravimetric assay studies.

    Science.gov (United States)

    Omotuyi, Olaposi; Matsunaga, Hayato; Ueda, Hiroshi

    2015-01-01

    During preconditioning, lipopolysaccharide (LPS) selectively activates TLR4/MD-2/Toll/IL-1 receptor-domain-containing adaptor inducing IFN-β (TRIF) pathway instead of pro-inflammatory myeloid differentiation protein-88 (MyD88)/MyD88-adaptor-like protein (MAL) pathway. Extracellular prothymosin alpha (ProTα) is also known to selectively activate the TLR4/MD2/TRIF-IRF3 pathway in certain diseased conditions. In the current study, biophysical evidence for ProTα/TLR4/MD-2 complex formation and its interaction dynamics have been studied. Gravimetric assay was used to investigate ProTα/TLR4/MD-2 complex formation while molecular dynamics (MD) simulation was used to study its interaction dynamics. Through electrostatic interaction, full-length ProTα (F-ProTα) C-terminal peptide (aa 91 - 111) superficially interacts with similar TLR4/MD-2 (KD = 273.36 nm vs 16.07 μg/ml [LPS]) conformation with LPS at an overlapping three-dimensional space while F-ProTα is hinged to the TLR4 scaffold by one-amino acid shift-Mosoian domain (aa-51 - 90). Comparatively, F-ProTα better stabilizes MD-2 metastable states transition and mediates higher TLR4/MD-2 interaction than LPS. ProTα via its C-terminal peptide (aa 91 - 111) exhibits in vitro biophysical contact with TLR4/MD-2 complex conformation recognized by LPS at overlapping LPS-binding positions.

  1. Carboplatin binding to histidine

    Energy Technology Data Exchange (ETDEWEB)

    Tanley, Simon W. M. [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Diederichs, Kay [University of Konstanz, D-78457 Konstanz (Germany); Kroon-Batenburg, Loes M. J. [Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Levy, Colin [University of Manchester, 131 Princess Street, Manchester M1 7DN (United Kingdom); Schreurs, Antoine M. M. [Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

    2014-08-29

    An X-ray crystal structure showing the binding of purely carboplatin to histidine in a model protein has finally been obtained. This required extensive crystallization trials and various novel crystal structure analyses. Carboplatin is a second-generation platinum anticancer agent used for the treatment of a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine (in hen egg-white lysozyme; HEWL) showed the partial conversion of carboplatin to cisplatin owing to the high NaCl concentration used in the crystallization conditions. HEWL co-crystallizations with carboplatin in NaBr conditions have now been carried out to confirm whether carboplatin converts to the bromine form and whether this takes place in a similar way to the partial conversion of carboplatin to cisplatin observed previously in NaCl conditions. Here, it is reported that a partial chemical transformation takes place but to a transplatin form. Thus, to attempt to resolve purely carboplatin binding at histidine, this study utilized co-crystallization of HEWL with carboplatin without NaCl to eliminate the partial chemical conversion of carboplatin. Tetragonal HEWL crystals co-crystallized with carboplatin were successfully obtained in four different conditions, each at a different pH value. The structural results obtained show carboplatin bound to either one or both of the N atoms of His15 of HEWL, and this particular variation was dependent on the concentration of anions in the crystallization mixture and the elapsed time, as well as the pH used. The structural details of the bound carboplatin molecule also differed between them. Overall, the most detailed crystal structure showed the majority of the carboplatin atoms bound to the platinum centre; however, the four-carbon ring structure of the cyclobutanedicarboxylate moiety (CBDC) remained elusive. The potential impact of the results for the administration of carboplatin as an anticancer agent are described.

  2. Molecular binding of toxic phenothiazinium derivatives, azures to bovine serum albumin: A comparative spectroscopic, calorimetric, and in silico study.

    Science.gov (United States)

    Das, Somnath; Islam, Md Maidul; Jana, Gopal Chandra; Patra, Anirudha; Jha, Pradeep K; Hossain, Maidul

    2017-07-01

    In this paper, the comparative binding behavior of antimalarial drug azure A, azure B and azure C with bovine serum albumin (BSA) has been studied. The interaction has been confirmed by multispectroscopic (UV, fluorescence, Fourier transform infrared (FT-IR), and circular dichroism) and molecular docking techniques. The experimental results show that azure B has the highest BSA binding affinity followed by azure A and azure C. The experimental evidence of binding showed a static quenching mechanism in the interaction azures with BSA. The isothermal titration calorimetry result reveals that the binding was exothermic with positive entropy contribution in each case. The thermodynamic parameters ΔH, ΔG, and ΔS at 25°C were calculated, which indicates that the weak van der Waals forces and hydrogen bonding rather than the hydrophobic effect played an important role in the interaction. According to the theory of Förster nonradiative energy transfer, the distance (r) between the donor (BSA) and acceptor azures found to be azures-BSA system. Overall, experimental studies characterize the interaction dynamics and energetics of the binding of three toxic analogs towards the physiologically relevant serum albumins. We hope, the outcome of this work will be most helpful for synthesizing a new type of phenothiazinium derivatives of the better therapeutic application. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Competitive binding of (-)-epigallocatechin-3-gallate and 5-fluorouracil to human serum albumin: A fluorescence and circular dichroism study

    Science.gov (United States)

    Yuan, Lixia; Liu, Min; Liu, Guiqin; Li, Dacheng; Wang, Zhengping; Wang, Bingquan; Han, Jun; Zhang, Min

    2017-02-01

    Combination therapy with more than one therapeutic agent can improve therapeutic efficiency and decrease drug resistance. In this study, the interactions of human serum albumin (HSA) with individual or combined anticancer drugs, (-)-epigallocatechin-3-gallate (EGCG) and 5-fluorouracil (FU), were investigated by fluorescence and circular dichroism (CD) spectroscopy. The results demonstrated that the interaction of EGCG or FU with HSA is a process of static quenching and EGCG formed a more stable complex. The competitive experiments of site markers suggested that both anti-carcinogens mainly bound to site I (subdomain IIA). The interaction forces which play important roles in the binding process were discussed based on enthalpy and entropy changes. Moreover, the competition binding model for a ternary system was proposed so as to precisely calculate the binding parameters. The results demonstrated that one drug decreased the binding affinity of another drug with HSA, resulting in the increasing free drug concentration at the action sites. CD studies indicated that there was an alteration in HSA secondary structure due to the binding of EGCG and FU. It can be concluded that the combination of EGCG with FU may enhance anticancer efficacy. This finding may provide a theoretical basis for clinical treatments.

  4. Experimental and molecular modeling studies on the DNA-binding of diazacyclam-based acrocyclic copper complex.

    Science.gov (United States)

    Shahabadi, Nahid; Hakimi, Mohammad; Morovati, Teimoor; Falsafi, Monireh; Fili, Soraya Moradi

    2017-02-01

    The interaction of a new macrocyclic copper complex, [CuL(NO 3 ) 2 ] in which L is 1,3,6,10,12,15-hexaaza tricyclo[13.3.1.1 6,10 ] eicosane was investigated in vitro under simulated physiological conditions by multi-spectroscopic techniques and molecular modeling study. The fluorescence spectroscopy and UV absorption spectroscopy indicated the complex interacted with ct-DNA in a groove binding mode while the binding constant of UV-vis and the number of binding sites were 1.0±0.2×10 4 Lmol -1 and 1.01, respectively. The fluorometric studies showed that the reaction between the complex with ct-DNA is exothermic (ΔH=14.85kJmol -1 ; ΔS=109.54Jmol -1 K -1 ). Circular dichroism spectroscopy (CD) was employed to measure the conformational change of DNA in the presence of [CuL(NO 3 ) 2 ] complex. Furthermore, the complex induces detectable changes in the viscosity of DNA. The molecular modeling results illustrated that the complex strongly binds to groove of DNA. Experimental and molecular modeling results showed that Cu(II) complex bound to DNA by a groove binding mode. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. New silver(I) complex with diazafluorene based ligand: Synthesis, characterization, investigation of in vitro DNA binding and antimicrobial studies

    Science.gov (United States)

    Movahedi, Elaheh; Rezvani, Ali Reza

    2017-07-01

    A novel diazafluorene based complex with silver, [Ag(dian)2 ] NO3 , where dian is N-(4,5-diazafluoren-9-ylidene)aniline, has been prepared and characterized by elemental analysis, IR spectroscopy, 1HNMR, UV-Vis spectroscopy and cyclic voltammetry. In order to explore the relationship between the structure and biological properties, DNA binding propensity and in vitro antibacterial property have also been studied. The mode of DNA-complex interaction has been investigated by electronic absorption titration, luminescence titration, competitive binding experiment, effect of ionic strength, thermodynamic studies, viscometric evaluation, circular dichroism spectroscopy and cyclic voltammetry. The results reveal that the complex binds to CT-DNA in a moderate intercalation capability with the partial insertion of a planar dian ligand between the base stacks of double-stranded DNA with binding constant (Kb) of 2.4 × 105 M-1. The viscosities and CD spectra of the DNA provide strong evidence for the intercalation. An in vitro antibacterial efficacy of the Ag(I) complex on a series of Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) indicates that the complex exhibits a marked antibacterial activity. The minimum inhibitory concentrations of the complex indicate that it exhibits much higher antibacterial effect on standard bacterial strains of Escherichia coli and Staphylococcus aureus than those of silver nitrate, silver sulfadiazine. The bacterial inhibitions of the silver(I) complex are closely agreed to its DNA binding affinities.

  6. Binding of low molecular mass compounds to proteins studied by liquid chromatographic techniques

    Czech Academy of Sciences Publication Activity Database

    Cserháti, T.; Forgács, E.; Deyl, Zdeněk; Mikšík, Ivan; Eckhardt, Adam

    2003-01-01

    Roč. 17, č. 6 (2003), s. 353-360 ISSN 0269-3879 Institutional research plan: CEZ:AV0Z5011922 Keywords : protein binding Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.269, year: 2003

  7. Near relativistic study of binded levels in atoms. Application to alkaline atoms

    International Nuclear Information System (INIS)

    Varade, A.; Delgado-Barrio, G.; Villarreal, P.

    1985-01-01

    A model is described for the calculation of the atomic binding energies. The Pauli equation has been solved with a local potential. The results for alkaline atoms are reported here and compared with the perturbative calculation and experimental data. (author)

  8. A comparative study of the metal binding behavior of alanine based bis-thiourea isomers

    OpenAIRE

    Fakhar, Imran; Yamin, Bohari M.; Hasbullah, Siti Aishah

    2017-01-01

    Two new symmetrical bis-thiourea, 2,2?-[{(terephthaloylbis(azanediyl)bis(carbonothioyl) bis(azanediyl)}dipropanoic acid] (1A) and 3,3?-[{(terephthaloylbis(azanediyl)bis (carbonothioyl)bis(azanediyl)} dipropanoic acid] (1B) were synthesized by the reaction of terephthaloyl chloride with ?- and ?-alanine in good yields. Their binding properties were investigated with various metal cations using UV?Vis titration experiments. Both isomers exhibited effective binding with Ag+, Cu2+, Hg2+, Pb2+, Fe...

  9. 1HNMR study of methotrexate serum albumin (MTX SA) binding in rheumatoid arthritis

    Science.gov (United States)

    Sułkowska, A.; Maciążek-Jurczyk, M.; Bojko, B.; Równicka, J.; Sułkowski, W. W.

    2008-11-01

    Rheumatoid arthritis (RA) is an immunologically depended disease. It is characterized by a chronic, progressive inflammatory process. Methotrexate (4-amino-10-methylfolic acid, MTX) is the modifying drug used to treat RA. The aim of the presented studies is to determine the low affinity binding site of MTX in bovine (BSA) and human (HSA) serum albumin with the use of proton nuclear magnetic resonance ( 1HNMR) spectroscopy. The analysis of 1HNMR spectra of MTX in the presence of serum albumin (SA) allows us to observe the interactions between aromatic rings of the drug and the rings of amino acids located in the hydrophobic subdomains of the protein. On the basis of the chemical shifts σ [ppm] and the relaxation times T1 [s] of drug protons the hydrophobic interaction between MTX-SA and the stoichiometric molar ratio of the complex was evaluated. This work is a part of a spectroscopic study on MTX-SA interactions [A. Sułkowska, M. Maciążek, J. Równicka, B. Bojko, D. Pentak, W.W. Sułkowski, J. Mol. Struct. 834-836 (2007) 162-169].

  10. DNA binding studies of Sunset Yellow FCF using spectroscopy, viscometry and electrochemical techniques

    Science.gov (United States)

    Asaadi, Sara; Hajian, Reza

    2017-10-01

    Color is one of the important factors in food industry. All food companies use synthetic pigments to improve the aesthetic of products. Studies on the interaction between deoxyribonucleic acid (DNA) and food dye molecules is important because DNA is responsible for some processes including replication and transcription of cells, mutations, genetic diseases, and some synthetic chemical nucleases. In this study, the molecular interaction between Sunset Yellow FCF (SY) as a common food coloring additive and calf thymus DNA (ct-DNA) has been studied using UV-Vis spectrophotometry, spectrofluorometry, Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry and viscometry techniques. The binding constant between ct-DNA and SY in phosphate buffer solution (pH 7.4) was calculated as 2.09 × 103 L mol-1. The non-electrostatic bonding constant (K0t) was almost consistent and the ratio of K0t/Kb increased by increasing the ionic strength in the range of 0.01-0.1 mol L-1 of KCl. This observation shows that, the molecular bonding of SY to ct-DNA is a combination of electrostatic and intercalation interactions. In the electrochemical studies, an oxidation peak at 0.71 V and a reduction peak at about 0.63 V was observed with the peak potential difference (ΔEp) of 0.08 V, showing a reversible process. The oxidation and reduction peaks were significantly decreased in the presence of ct-DNA and the reduction peak current shifted to negative values. In spectrofluorometric study, the fluorescence intensity of SY increased dramatically after successive addition of DNA due to the increasing of molecular surface area and decreasing of impact frequency between solvent and SY-DNA adduct. Moreover, viscometric study shows that the increasing of viscosity for SY solution in the presence of DNA is due to the intercalation mechanism with double strand DNA (ds-DNA).

  11. Treatment of advanced, recurrent, resistant to previous treatments basal and squamous cell skin carcinomas with a synergistic formulation of interferons. Open, prospective study

    Directory of Open Access Journals (Sweden)

    Lopez-Saura Pedro

    2009-07-01

    Full Text Available Abstract Background Aggressive non-melanoma skin cancer (deeply infiltrating, recurrent, and morphea form lesions are therapeutically challenging because they require considerable tissue loss and may demand radical disfiguring surgery. Interferons (IFN may provide a non-surgical approach to the management of these tumors. The aim of this work was to evaluate the effect of a formulation containing IFNs-α and -γ in synergistic proportions on patients with recurrent, advanced basal cell (BCC or squamous cell skin carcinomas (SCSC. Methods Patients with extensive, recurrent, resistant to other procedures BCC or SCSC received the IFN formulation peri- and intralesionally, three times per week for 3 weeks. They had been previously treated with surgery and/or radiotherapy or chemotherapy. Thirteen weeks after the end of treatment, the original lesion sites were examined for histological evidence of remaining tumor. Results Sixteen elder (median 70 years-old patients were included. They beared 12 BCC and 4 SCSC ranging from 1.5 to 12.5 cm in the longest dimension. At the end of treatment 47% CR (complete tumor elimination, 40% PR (>30% tumor reduction, and 13% stable disease were obtained. None of the patients relapsed during the treatment period. The median duration of the response was 38 months. Only one patient with complete response had relapsed until today. Principal adverse reactions were influenza-like symptoms well known to occur with interferon therapy, which were well tolerated. Conclusion The peri- and intralesional combination of IFNs-α and -γ was safe and showed effect for the treatment of advanced, recurrent and resistant to previous treatments of BCC and SCSC in elder patients. This is the first report of such treatment in patients with advance non-melanoma skin cancer. The encouraging result justifies further confirmatory trials. Trial registration Current Controlled Trials RPCEC00000052.

  12. Treatment of advanced, recurrent, resistant to previous treatments basal and squamous cell skin carcinomas with a synergistic formulation of interferons. Open, prospective study

    International Nuclear Information System (INIS)

    Anasagasti-Angulo, Lorenzo; Garcia-Vega, Yanelda; Barcelona-Perez, Silvia; Lopez-Saura, Pedro; Bello-Rivero, Iraldo

    2009-01-01

    Aggressive non-melanoma skin cancer (deeply infiltrating, recurrent, and morphea form lesions) are therapeutically challenging because they require considerable tissue loss and may demand radical disfiguring surgery. Interferons (IFN) may provide a non-surgical approach to the management of these tumors. The aim of this work was to evaluate the effect of a formulation containing IFNs-α and -γ in synergistic proportions on patients with recurrent, advanced basal cell (BCC) or squamous cell skin carcinomas (SCSC). Patients with extensive, recurrent, resistant to other procedures BCC or SCSC received the IFN formulation peri- and intralesionally, three times per week for 3 weeks. They had been previously treated with surgery and/or radiotherapy or chemotherapy. Thirteen weeks after the end of treatment, the original lesion sites were examined for histological evidence of remaining tumor. Sixteen elder (median 70 years-old) patients were included. They beared 12 BCC and 4 SCSC ranging from 1.5 to 12.5 cm in the longest dimension. At the end of treatment 47% CR (complete tumor elimination), 40% PR (>30% tumor reduction), and 13% stable disease were obtained. None of the patients relapsed during the treatment period. The median duration of the response was 38 months. Only one patient with complete response had relapsed until today. Principal adverse reactions were influenza-like symptoms well known to occur with interferon therapy, which were well tolerated. The peri- and intralesional combination of IFNs-α and -γ was safe and showed effect for the treatment of advanced, recurrent and resistant to previous treatments of BCC and SCSC in elder patients. This is the first report of such treatment in patients with advance non-melanoma skin cancer. The encouraging result justifies further confirmatory trials. Current Controlled Trials RPCEC00000052

  13. Binding studies of guggulsterone-E to calf thymus DNA by multi-spectroscopic, calorimetric and molecular docking studies

    Science.gov (United States)

    Ikhlas, Shoeb; Ahmad, Masood

    2018-02-01

    Guggulsterone, a sterol found in plants is used as an ayurvedic medicine for many diseases such as obesity, internal tumors, ulcers etc. E and Z are two isoforms of guggulsterone, wherein guggulsterone-E (GUGE) has also been shown to have anticancer potential. Most of the anticancer drugs target nucleic acids. Therefore, we studied the mode of interaction between ctDNA and GUGE using UV-Vis, fluorescence and CD spectroscopy, isothermal calorimetry along with molecular docking studies. Hoechst 3325, ethidium bromide and rhodamine-B displacement experiments confirms that GUGE binds in the minor groove of DNA. ITC results further suggest these interactions to be feasible and spontaneous with hydrogen bond formation and van der waals interactions. Lastly, molecular docking also suggests GUGE to be a minor groove binder interacting through a single hydrogen bond formation between OH group of GUGE and nitrogen (N3) of adenosine (A6).

  14. Stability, protein binding and clearance studies of [99mTc]DTPA. Evaluation of a commercially available dry-kit

    DEFF Research Database (Denmark)

    Rehling, M

    1988-01-01

    the quality of a commercial [99mTc]DTPA preparation (C.I.S., France) with reference to stability, protein binding and accuracy of the determined plasma clearance values as a measure of GFR. The stability of the preparations was studied by thin-layer chromatography, the in vitro protein binding by Sephadex...... filtration after incubation with human serum albumin and in vivo protein binding by filtration of human plasma. The accuracy of the plasma clearance values was investigated by comparison with the simultaneously measured plasma clearance of [51Cr]EDTA. There was no detectable free pertechnetate or hydrolysed...... reduced technetium in eight vials five and six hours after the preparation. The in vitro protein binding 10 (20), 120 and 300 min after the preparation of eight vials was 2.3% (0.8%), 0.2% and 0.1%, respectively. The in vivo protein binding in 12 patients 5, 90 and 180 min after the injection was 0.3%, 0...

  15. Binding of naringin and naringenin with hen egg white lysozyme: A spectroscopic investigation and molecular docking study

    Science.gov (United States)

    Das, Sourav; Ghosh, Pooja; Koley, Sudipta; Singha Roy, Atanu

    2018-03-01

    The interactions of naringenin (NG) and naringin (NR) with Hen Egg White Lysozyme (HEWL) in aqueous medium have been investigated using UV-vis spectroscopy, steady-state fluorescence, circular dichroism (CD), Fourier Transform infrared spectroscopy (FT-IR) and molecular docking analyses. Both NG and NR can quench the intrinsic fluorescence of HEWL via static quenching mechanism. At 300 K, the value of binding constant (Kb) of HEWL-NG complex (5.596 ± 0.063 × 104 M- 1) was found to be greater than that of HEWL-NR complex (3.404 ± 0.407 × 104 M- 1). The negative ΔG° values in cases of both the complexes specify the spontaneous binding. The binding distance between the donor (HEWL) and acceptor (NG/NR) was estimated using the Försters theory and the possibility of non-radiative energy transfer from HEWL to NG/NR was observed. The presence of metal ions (Ca2 +, Cu2 + and Fe2 +) decreased the binding affinity of NG/NR towards HEWL. Synchronous fluorescence studies indicate the change in Trp micro-environment due to the incorporation of NG/NR into HEWL. CD and FT-IR studies indicated that the α-helicity of the HEWL was slightly enhanced due to ligand binding. NG and NR inhibited the enzymatic activity of HEWL and exhibited their affinity for the active site of HEWL. Molecular docking studies revealed that both NG and NR bind in the close vicinity of Trp 62 and Trp 63 residues which is vital for the catalytic activity.

  16. Structural characterization of binding mode of smoking cessation drugs to nicotinic acetylcholine receptors through study of ligand complexes with acetylcholine-binding protein.

    Science.gov (United States)

    Rucktooa, Prakash; Haseler, Claire A; van Elk, René; Smit, August B; Gallagher, Timothy; Sixma, Titia K

    2012-07-06

    Smoking cessation is an important aim in public health worldwide as tobacco smoking causes many preventable deaths. Addiction to tobacco smoking results from the binding of nicotine to nicotinic acetylcholine receptors (nAChRs) in the brain, in particular the α4β2 receptor. One way to aid smoking cessation is by the use of nicotine replacement therapies or partial nAChR agonists like cytisine or varenicline. Here we present the co-crystal structures of cytisine and varenicline in complex with Aplysia californica acetylcholine-binding protein and use these as models to investigate binding of these ligands binding to nAChRs. This analysis of the binding properties of these two partial agonists provides insight into differences with nicotine binding to nAChRs. A mutational analysis reveals that the residues conveying subtype selectivity in nAChRs reside on the binding site complementary face and include features extending beyond the first shell of contacting residues.

  17. The location and nature of general anesthetic binding sites on the active conformation of firefly luciferase; a time resolved photolabeling study.

    Directory of Open Access Journals (Sweden)

    Sivananthaperumal Shanmugasundararaj

    Full Text Available Firefly luciferase is one of the few soluble proteins that is acted upon by a wide variety of general anesthetics and alcohols; they inhibit the ATP-driven production of light. We have used time-resolved photolabeling to locate the binding sites of alcohols during the initial light output, some 200 ms after adding ATP. The photolabel 3-azioctanol inhibited the initial light output with an IC50 of 200 µM, close to its general anesthetic potency. Photoincorporation of [(3H]3-azioctanol into luciferase was saturable but weak. It was enhanced 200 ms after adding ATP but was negligible minutes later. Sequencing of tryptic digests by HPLC-MSMS revealed a similar conformation-dependence for photoincorporation of 3-azioctanol into Glu-313, a residue that lines the bottom of a deep cleft (vestibule whose outer end binds luciferin. An aromatic diazirine analog of benzyl alcohol with broader side chain reactivity reported two sites. First, it photolabeled two residues in the vestibule, Ser-286 and Ile-288, both of which are implicated with Glu-313 in the conformation change accompanying activation. Second, it photolabeled two residues that contact luciferin, Ser-316 and Ser-349. Thus, time resolved photolabeling supports two mechanisms of action. First, an allosteric one, in which anesthetics bind in the vestibule displacing water molecules that are thought to be involved in light output. Second, a competitive one, in which anesthetics bind isosterically with luciferin. This work provides structural evidence that supports the competitive and allosteric actions previously characterized by kinetic studies.

  18. Histochemical detection of sugar residues in lizard teeth (Liolaemus gravenhorsti: a lectin-binding study

    Directory of Open Access Journals (Sweden)

    MARCELA FUENZALIDA

    2000-01-01

    Full Text Available The structural diversity of the many oligosaccharide chains of surface glycoconjugates renders them likely candidates for modulators of cell-interactions, cellular movements, differentiation, and cellular recognition. A selection of different lectins was used to investigate the appearance of cellular distribution and changes in sugar residues during tooth development in the polyphyodont lizard, Liolaemus gravenhorsti. Lectins from three groups were used: (1 N-acetylgalactosamine specificity: BS-1, PNA, RCA-120; (2 N-acetylglucosamine specificity: ECA; and (3 fucose specificity: UEA 1 and LTA.. Digital images were processed using Scion Image. Grayscale graphics in each image were obtained. The lectins used showed a strong, wide distribution of the L-fucose and N-acetylgalactosamine at the cell surface and in the cytoplasm of multinucleate odontoclast cell, while mononuclear odontoclast cells showed no binding, suggesting some roles that the residues sugar might play in the resorption of dentine or with multinucleation of odontoclast after the attachment to the dentine surface in this polyphyodont species. Further studies must be planned to determine the specific identities of these glycoconjugates,and to elucidate the roles played by these sugar residues in the complex processes related to odontogenesis in polyphyodont species.

  19. A study on antigenicity and receptor-binding ability of fragment 450-650 of the spike protein of SARS coronavirus

    International Nuclear Information System (INIS)

    Zhao Jincun; Wang Wei; Yuan Zhihong; Jia Rujing; Zhao Zhendong; Xu Xiaojun; Lv Ping; Zhang Yan; Jiang Chengyu; Gao Xiaoming

    2007-01-01

    The spike (S) protein of SARS coronavirus (SARS-CoV) is responsible for viral binding with ACE2 molecules. Its receptor-binding motif (S-RBM) is located between residues 424 and 494, which folds into 2 anti-parallel β-sheets, β5 and β6. We have previously demonstrated that fragment 450-650 of the S protein (S450-650) is predominantly recognized by convalescent sera of SARS patients. The N-terminal 60 residues (450-510) of the S450-650 fragment covers the entire β6 strand of S-RBM. In the present study, we demonstrate that patient sera predominantly recognized 2 linear epitopes outside the β6 fragment, while the mouse antisera, induced by immunization of BALB/c mice with recombinant S450-650, mainly recognized the β6 strand-containing region. Unlike patient sera, however, the mouse antisera were unable to inhibit the infectivity of S protein-expressing (SARS-CoV-S) pseudovirus. Fusion protein between green fluorescence protein (GFP) and S450-650 (S450-650-GFP) was able to stain Vero E6 cells and deletion of the β6 fragment rendered the fusion product (S511-650-GFP) unable to do so. Similarly, recombinant S450-650, but not S511-650, was able to block the infection of Vero E6 cells by the SARS-CoV-S pseudovirus. Co-precipitation experiments confirmed that S450-650 was able to specifically bind with ACE2 molecules in lysate of Vero E6 cells. However, the ability of S450-510, either alone or in fusion with GFP, to bind with ACE2 was significantly poorer compared with S450-650. Our data suggest a possibility that, although the β6 strand alone is able to bind with ACE2 with relatively high affinity, residues outside the S-RBM could also assist the receptor binding of SARS-CoV-S protein

  20. Binding and Signaling Studies Disclose a Potential Allosteric Site for Cannabidiol in Cannabinoid CB2Receptors.

    Science.gov (United States)

    Martínez-Pinilla, Eva; Varani, Katia; Reyes-Resina, Irene; Angelats, Edgar; Vincenzi, Fabrizio; Ferreiro-Vera, Carlos; Oyarzabal, Julen; Canela, Enric I; Lanciego, José L; Nadal, Xavier; Navarro, Gemma; Borea, Pier Andrea; Franco, Rafael

    2017-01-01

    The mechanism of action of cannabidiol (CBD), the main non-psychotropic component of Cannabis sativa L., is not completely understood. First assumed that the compound was acting via cannabinoid CB 2 receptors (CB 2 Rs) it is now suggested that it interacts with non-cannabinoid G-protein-coupled receptors (GPCRs); however, CBD does not bind with high affinity to the orthosteric site of any GPCR. To search for alternative explanations, we tested CBD as a potential allosteric ligand of CB 2 R. Radioligand and non-radioactive homogeneous binding, intracellular cAMP determination and ERK1/2 phosphorylation assays were undertaken in heterologous systems expressing the human version of CB 2 R. Using membrane preparations from CB 2 R-expressing HEK-293T (human embryonic kidney 293T) cells, we confirmed that CBD does not bind with high affinity to the orthosteric site of the human CB 2 R where the synthetic cannabinoid, [ 3 H]-WIN 55,212-2, binds. CBD was, however, able to produce minor but consistent reduction in the homogeneous binding assays in living cells using the fluorophore-conjugated CB 2 R-selective compound, CM-157. The effect on binding to CB 2 R-expressing living cells was different to that exerted by the orthosteric antagonist, SR144528, which decreased the maximum binding without changing the K D . CBD at nanomolar concentrations was also able to significantly reduce the effect of the selective CB 2 R agonist, JWH133, on forskolin-induced intracellular cAMP levels and on activation of the MAP kinase pathway. These results may help to understand CBD mode of action and may serve to revisit its therapeutic possibilities.

  1. Human PD-1 binds differently to its human ligands: a comprehensive modeling study.

    Science.gov (United States)

    Viricel, Clement; Ahmed, Marawan; Barakat, Khaled

    2015-04-01

    Programmed death-1 (PD-1) is a potent inhibitory receptor of T cells which binds to two different ligands, namely PD-L1 and PD-L2, and upon binding, it inhibits T cell activation, differentiation, and proliferation, leading to a state of immune tolerance. Blocking these interactions recently emerged as a 'game changer' approach in immunotherapy. Despite the significant therapeutic potential of targeting the PD-1 pathway, the interaction between human PD-1 and its two human ligands is not fully understood. Current crystal structures describe the interactions of mouse PD-1 with human PD-L1 or mouse PD-L2. However, recent mutational and nuclear magnetic resonance (NMR) analyses suggest that human PD-1 binds its human ligands differently compared to their mouse counterparts. No detailed model is currently available to consistently fit these data. The lack of these accurate structures constitutes a high barrier against rationally developing more effective and safer agents targeting these interactions. Here we describe for the first time two accurate models for human PD-1 bound to its two human ligands. Our methodology involved combining molecular dynamics (MD) simulations with protein-protein docking and binding energy analysis to predict the most probable binding conformations for PD1 to its ligands. Our results confirm the available experimental NMR and mutational data and reveal the most accurate atomistic details so far of how human PD-1 binds to human PD-Ls and why the two ligands bind with different affinities to the same receptor. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Binding and Signaling Studies Disclose a Potential Allosteric Site for Cannabidiol in Cannabinoid CB2 Receptors

    Directory of Open Access Journals (Sweden)

    Eva Martínez-Pinilla

    2017-10-01

    Full Text Available The mechanism of action of cannabidiol (CBD, the main non-psychotropic component of Cannabis sativa L., is not completely understood. First assumed that the compound was acting via cannabinoid CB2 receptors (CB2Rs it is now suggested that it interacts with non-cannabinoid G-protein-coupled receptors (GPCRs; however, CBD does not bind with high affinity to the orthosteric site of any GPCR. To search for alternative explanations, we tested CBD as a potential allosteric ligand of CB2R. Radioligand and non-radioactive homogeneous binding, intracellular cAMP determination and ERK1/2 phosphorylation assays were undertaken in heterologous systems expressing the human version of CB2R. Using membrane preparations from CB2R-expressing HEK-293T (human embryonic kidney 293T cells, we confirmed that CBD does not bind with high affinity to the orthosteric site of the human CB2R where the synthetic cannabinoid, [3H]-WIN 55,212-2, binds. CBD was, however, able to produce minor but consistent reduction in the homogeneous binding assays in living cells using the fluorophore-conjugated CB2R-selective compound, CM-157. The effect on binding to CB2R-expressing living cells was different to that exerted by the orthosteric antagonist, SR144528, which decreased the maximum binding without changing the KD. CBD at nanomolar concentrations was also able to significantly reduce the effect of the selective CB2R agonist, JWH133, on forskolin-induced intracellular cAMP levels and on activation of the MAP kinase pathway. These results may help to understand CBD mode of action and may serve to revisit its therapeutic possibilities.

  3. Molecular modeling study on the allosteric inhibition mechanism of HIV-1 integrase by LEDGF/p75 binding site inhibitors.

    Directory of Open Access Journals (Sweden)

    Weiwei Xue

    Full Text Available HIV-1 integrase (IN is essential for the integration of viral DNA into the host genome and an attractive therapeutic target for developing antiretroviral inhibitors. LEDGINs are a class of allosteric inhibitors targeting LEDGF/p75 binding site of HIV-1 IN. Yet, the detailed binding mode and allosteric inhibition mechanism of LEDGINs to HIV-1 IN is only partially understood, which hinders the structure-based design of more potent anti-HIV agents. A molecular modeling study combining molecular docking, molecular dynamics simulation, and binding free energy calculation were performed to investigate the interaction details of HIV-1 IN catalytic core domain (CCD with two recently discovered LEDGINs BI-1001 and CX14442, as well as the LEDGF/p75 protein. Simulation results demonstrated the hydrophobic domain of BI-1001 and CX14442 engages one subunit of HIV-1 IN CCD dimer through hydrophobic interactions, and the hydrophilic group forms hydrogen bonds with HIV-1 IN CCD residues from other subunit. CX14442 has a larger tert-butyl group than the methyl of BI-1001, and forms better interactions with the highly hydrophobic binding pocket of HIV-1 IN CCD dimer interface, which can explain the stronger affinity of CX14442 than BI-1001. Analysis of the binding mode of LEDGF/p75 with HIV-1 IN CCD reveals that the LEDGF/p75 integrase binding domain residues Ile365, Asp366, Phe406 and Val408 have significant contributions to the binding of the LEDGF/p75 to HIV1-IN. Remarkably, we found that binding of BI-1001 and CX14442 to HIV-1 IN CCD induced the structural rearrangements of the 140 s loop and oration displacements of the side chains of the three conserved catalytic residues Asp64, Asp116, and Glu152 located at the active site. These results we obtained will be valuable not only for understanding the allosteric inhibition mechanism of LEDGINs but also for the rational design of allosteric inhibitors of HIV-1 IN targeting LEDGF/p75 binding site.

  4. Cotton Study: Albumin Binding and its Effect on Elastase Activity in the Chronic Non-Healing Wound

    Energy Technology Data Exchange (ETDEWEB)

    Castro, N.; Goheen, S.

    2005-01-01

    Cotton, as it is used in wound dressings is composed of nearly pure cellulose. During the wound-healing process, cotton is exposed to various blood components including water, salts, cells, and blood proteins. Albumin is the most prominent protein in blood. Elastase is an enzyme secreted by white blood cells and takes an active role in tissue reconstruction. In the chronic non-healing wound, elastase is often over-expressed such that this enzyme digests tissue and growth factors, and interferes with the normal healing process. Our goal is to design a cotton wound dressing that will sequester elastase or assist in reducing elastase activity in the presence of other blood proteins such as albumin. The ability of cotton and various cotton derivatives to sequester elastase and albumin has been studied by examining the adsorption of these two proteins separately. We undertook the present work to confirm the binding of albumin to cotton and to quantify the activity of elastase in the presence of various derivatives of cotton. We previously observed a slight increase in elastase activity when exposed to cotton. We also observed a continuous accumulation of albumin on cotton using high-performance liquid chromatography methods. In the present study, we used an open-column-absorption technique coupled with a colorimetric protein assay to confirm losses of albumin to cotton. We have also confirmed increased elastase activity after exposure to cotton. The results are discussed in relation to the porosity of cotton and the use of cotton for treating chronic non-healing wounds.

  5. Docking Studies of Binding of Ethambutol to the C-Terminal Domain of the Arabinosyltransferase from Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Guillermo Salgado-Moran

    2013-01-01

    Full Text Available The binding of ethambutol to the C-terminal domain of the arabinosyltransferase from Mycobacterium tuberculosis was studied. The analysis was performed using an in silico approach in order to find out, by docking calculations and energy descriptors, the conformer of Ethambutol that forms the most stable complex with the C-terminal domain of arabinosyltransferase. The complex shows that location of the Ethambutol coincides with the cocrystallization ligand position and that amino acid residues ASH1051, ASN740, ASP1052, and ARG1055 should be critical in the binding of Ethambutol to C-terminal domain EmbC.

  6. Timing of dose relative to sexual intercourse attempt in previous sildenafil citrate users treated with tadalafil: a geographical comparison from a single arm, open-label study.

    Science.gov (United States)

    Rubio-Aurioles, Eusebio; Glina, Sidney; Abdo, Carmita H N; Hernandez-Serrano, Ruben; Rampazzo, Claudia; Sotomayor, Mariano; West, Teena M; Gallagher, Gabrielle L; Lenero, Enrique

    2009-10-01

    Previous research has demonstrated that sildenafil citrate users alter dosing-sexual attempt behavior when switched to tadalafil. The impact of geography and culture on sexual behavior with phosphodiesterase type 5 (PDE5) inhibitor treatment has not been fully investigated. To describe and compare the changes in dosing-sexual attempt behavior with sildenafil citrate vs. tadalafil treatment across four distinct geographies: Asia, Australia/New Zealand (ANZ), Central Eastern Europe/Middle East (CEE/ME), and Latin America (LA). Data from a single-arm, open-label clinical trial conducted in 21 countries from November 2002 to May 2004 were used in this analysis. Men with erectile dysfunction and a history of > or =6-week prior sildenafil citrate use continued sildenafil citrate treatment for 4 weeks then switched to tadalafil for 8 weeks. Dosing instructions were provided. Timing of dose and sexual intercourse was assessed through patient diaries for the final 4 weeks of each treatment period. A total of 2,760 men were enrolled: Asia 15.8%; ANZ 29.4%; CEE/ME 19.7%; LA 35.1%. The median time from dosing to intercourse was significantly increased during tadalafil treatment across all geographical regions; however, the magnitude of increase differed significantly by geography (P geography. However, the extent to which sexual behavior alters is not uniform across geographical regions, suggesting that dosing instructions and duration of drug effectiveness, in combination with personal and cultural preferences, may determine sexual behavior with PDE5 inhibitor use.

  7. Prognostic factors in multiple myeloma: definition of risk groups in 410 previously untreated patients: a Grupo Argentino de Tratamiento de la Leucemia Aguda study.

    Science.gov (United States)

    Corrado, C; Santarelli, M T; Pavlovsky, S; Pizzolato, M

    1989-12-01

    Four hundred ten previously untreated multiple myeloma patients entered onto two consecutive Grupo Argentino de Tratamiento de la Leucemia Aguda (GATLA) protocols were analyzed to identify significant prognostic factors influencing survival. The univariate analysis selected the following variables: performance status, renal function, percentage of bone marrow plasma cells at diagnosis, hemoglobin, and age. A multivariate analysis showed that performance status, renal function, percentage of bone marrow plasma cells, hemoglobin, and age were the best predictive variables for survival. A score was assigned to each patient according to these variables, which led to their classification in three groups: good, intermediate, and poor risk, with a probability of survival of 26% and 10% at 96 months, and 5% at 56 months, and median survival of 60, 37, and 14 months, respectively (P = .0000). In our patient population, this model proved to be superior to the Durie-Salmon staging system in defining prognostic risk groups, and separating patients with significantly different risks within each Durie-Salmon stage.

  8. Spectroscopic study of interaction between osthole and human serum albumin: Identification of possible binding site of the compound

    International Nuclear Information System (INIS)

    Bijari, Nooshin; Shokoohinia, Yalda; Ashrafi-Kooshk, Mohammad Reza; Ranjbar, Samira; Parvaneh, Shahram; Moieni-Arya, Maryam; Khodarahmi, Reza

    2013-01-01

    The studies on the interaction between human serum albumin (HSA) and drugs have been an interesting research field in life science, chemistry and clinical medicine. Osthole possesses a variety of pharmacological activities including anti-tumor, anti-inflammation, anti-seizure, anti-hyperlipidemic and anti-osteoporosis effects. The interaction of osthole with HSA and its binding site in HSA by spectroscopic methods is the subject of this work. By monitoring the intrinsic fluorescence of the single Trp 214 residue and performing site markers displacement measurements, the specific binding of osthole in the vicinity of Sudlow's site I of HSA has been clarified. The changes in the secondary structure of HSA after its complexation with ligand were studied with CD spectroscopy, which indicate that osthole induced only a slight decrease in the helix structural content of the protein. In addition, the mean distance between osthole and HSA fluorophores is estimated to be 4.96 nm using Föster's equation on the basis of the fluorescence energy transfer. Furthermore, the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues does not have obvious changes. Osthole can quench the intrinsic fluorescence of HSA by dynamic quenching, and analysis of the thermodynamic parameters of binding showed that hydrophobic interactions play an important role in the stabilizing of the complex. Increase of protein surface hydrophobicity (PSH) was also observed upon the osthole binding. -- Highlights: • Hydrophobic interactions play an important role in osthole–HSA interaction. • Sudlow's I site is possible binding site of osthole. • Osthole inhibits esterase activity of HSA. • Osthole binding induces no gross protein structural changes

  9. Spectroscopic study of interaction between osthole and human serum albumin: Identification of possible binding site of the compound

    Energy Technology Data Exchange (ETDEWEB)

    Bijari, Nooshin [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Shokoohinia, Yalda [Department of Pharmacognosy and Biotechnology, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Ashrafi-Kooshk, Mohammad Reza; Ranjbar, Samira; Parvaneh, Shahram [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Moieni-Arya, Maryam [Student Research Committee, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Khodarahmi, Reza, E-mail: rkhodarahmi@mbrc.ac.ir [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Department of Pharmacognosy and Biotechnology, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

    2013-11-15

    The studies on the interaction between human serum albumin (HSA) and drugs have been an interesting research field in life science, chemistry and clinical medicine. Osthole possesses a variety of pharmacological activities including anti-tumor, anti-inflammation, anti-seizure, anti-hyperlipidemic and anti-osteoporosis effects. The interaction of osthole with HSA and its binding site in HSA by spectroscopic methods is the subject of this work. By monitoring the intrinsic fluorescence of the single Trp{sub 214} residue and performing site markers displacement measurements, the specific binding of osthole in the vicinity of Sudlow's site I of HSA has been clarified. The changes in the secondary structure of HSA after its complexation with ligand were studied with CD spectroscopy, which indicate that osthole induced only a slight decrease in the helix structural content of the protein. In addition, the mean distance between osthole and HSA fluorophores is estimated to be 4.96 nm using Föster's equation on the basis of the fluorescence energy transfer. Furthermore, the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues does not have obvious changes. Osthole can quench the intrinsic fluorescence of HSA by dynamic quenching, and analysis of the thermodynamic parameters of binding showed that hydrophobic interactions play an important role in the stabilizing of the complex. Increase of protein surface hydrophobicity (PSH) was also observed upon the osthole binding. -- Highlights: • Hydrophobic interactions play an important role in osthole–HSA interaction. • Sudlow's I site is possible binding site of osthole. • Osthole inhibits esterase activity of HSA. • Osthole binding induces no gross protein structural changes.

  10. DNA-binding, spectroscopic and antimicrobial studies of palladium(II) complexes containing 2,2'-bipyridine and 1-phenylpiperazine

    Science.gov (United States)

    Shoukry, Azza A.; Mohamed, Mervat S.

    2012-10-01

    With the purpose of evaluating the ability of Pd(II) complex to interact with DNA molecule as the main biological target, two new complexes [Pd(bpy)(OH2)2] (1) and [Pd(Phenpip)(OH2)2] (2), where (bpy = 2,2'-bipyridine; Phenpip = 1-phenylpiperazine), have been synthesized and the binding properties of these complexes with CT-DNA were investigated. The intrinsic binding constants (Kb) calculated from UV-Vis absorption studies were 3.78 × 103 M-1 and 4.14 × 103 M-1 for complexes 1 and 2 respectively. Thermal denaturation has been systematically studied by spectrophotometric method and the calculated ΔTm was nearly 5 °C for each complex. All the results suggest an electrostatic and/or groove binding mode for the interaction between the complexes and CT-DNA. The redox behavior of the two complexes in the absence and in the presence of calf thymus DNA has been investigated by cyclic voltammetry. The cyclic voltammogram exhibits one quasi-reversible redox wave. The change in E1/2, ΔEp and Ipc/Ipa supports that the two complexes exhibit strong binding to calf thymus DNA. Further insight into the binding of complexes with CT-DNA has been made by gel electrophoresis, where the binding of complexes is confirmed through decreasing the intensity of DNA bands. The two complexes have been screened for their antimicrobial activities using the disc diffusion method against some selected Gram-positive and Gram-negative bacteria. The activity data showed that both complexes were more active against Gram-negative than Gram-positive bacteria. It may be concluded that the antimicrobial activity of the compounds is related to cell wall structure of bacteria.

  11. Recommendations for Conducting Differential Item Functioning (DIF) Analyses for Students with Disabilities Based on Previous DIF Studies. Research Report. ETS RR-11-34

    Science.gov (United States)

    Buzick, Heather; Stone, Elizabeth

    2011-01-01

    The purpose of this study is to help ensure that strategies for differential item functioning (DIF) detection for students with disabilities are appropriate and lead to meaningful results. We surveyed existing DIF studies for students with disabilities and describe them in terms of study design, statistical approach, sample characteristics, and…

  12. Interaction of phenylbutazone and colchicine in binding to serum albumin in rheumatoid therapy: 1H NMR study

    Science.gov (United States)

    Maciążek-Jurczyk, M.; Sułkowska, A.; Bojko, B.; Równicka-Zubik, J.; Sułkowski, W. W.

    2009-09-01

    The monitoring of drug concentration in blood serum is necessary in multi-drug therapy. Mechanism of drug binding with serum albumin (SA) is one of the most important factors which determine drug concentration and its transport to the destination tissues. In rheumatoid diseases drugs which can induce various adverse effects are commonly used in combination therapy. Such proceeding may result in the enhancement of those side effects due to drug interaction. Interaction of phenylbutazone and colchicine in binding to serum albumin and competition between them in gout has been studied by proton nuclear magnetic resonance ( 1H NMR) technique. The aim of the study was to determine the low affinity binding sites, the strength and kind of interaction between serum albumin and drugs used in combination therapy. The study of competition between phenylbutazone and colchicine in binding to serum albumin points to the change of their affinity to serum albumin in the ternary systems. This should be taken into account in multi-drug therapy. This work is a subsequent part of the spectroscopic study on Phe-COL-SA interactions [A. Sułkowska, et al., J. Mol. Struct. 881 (2008) 97-106].

  13. Circular Dichroism of G-Quadruplex: A Laboratory Experiment for the Study of Topology and Ligand Binding

    Science.gov (United States)

    Carvalho, Josue´; Queiroz, João A.; Cruz, Carla

    2017-01-01

    Circular dichroism (CD) has emerged as one of the standard biophysical techniques for the study of guaninequadruplex (G4) folding, cation effect, and ligand binding. The utility of this technique is based on its robustness, ease of use, and requirement of only small quantities of nucleic acid. This experiment is also extendable to the classroom…

  14. Identification of berberine as a direct thrombin inhibitor from traditional Chinese medicine through structural, functional and binding studies

    Science.gov (United States)

    Wang, Xing; Zhang, Yuxin; Yang, Ying; Wu, Xia; Fan, Hantian; Qiao, Yanjiang

    2017-03-01

    Thrombin acts as a key enzyme in the blood coagulation cascade and represents a potential drug target for the treatment of several cardiovascular diseases. The aim of this study was to identify small-molecule direct thrombin inhibitors from herbs used in traditional Chinese medicine (TCM). A pharmacophore model and molecular docking were utilized to virtually screen a library of chemicals contained in compositions of traditional Chinese herbs, and these analyses were followed by in vitro bioassay validation and binding studies. Berberine (BBR) was first confirmed as a thrombin inhibitor using an enzymatic assay. The BBR IC50 value for thrombin inhibition was 2.92 μM. Direct binding studies using surface plasmon resonance demonstrated that BBR directly interacted with thrombin with a KD value of 16.39 μM. Competitive binding assay indicated that BBR could bind to the same argartroban/thrombin interaction site. A platelet aggregation assay demonstrated that BBR had the ability to inhibit thrombin-induced platelet aggregation in washed platelets samples. This study proved that BBR is a direct thrombin inhibitor that has activity in inhibiting thrombin-induced platelet aggregation. BBR may be a potential candidate for the development of safe and effective thrombin-inhibiting drugs.

  15. Mechanistic Aspects of the Reversible Binding of SO2 on Arylplatinum Complexes: Experimental and ab Initio Studies

    NARCIS (Netherlands)

    Koten, G. van; Albrecht, M.A.; Gossage, R.A.; Frey, H.; Ehlers, A.W.; Baerends, E.J.; Merbach, A.E.

    2001-01-01

    The detailed mechanism of the reversible binding and fast exchange of SO2 on the organoplatinum(II) complex [PtI(NCN)], 1, has been studied experimentally in solution (C2F4Br2) using low-temperature NMR spectroscopy and theoretically by ab initio calculations. Direct bonding of SO2 and formation of

  16. Prospective monitoring and self-report of previous falls among older women at high risk of falls and fractures: a study of comparison and agreement

    Science.gov (United States)

    Garcia, Patrícia A.; Dias, João M. D.; Silva, Silvia L. A.; Dias, Rosângela C.

    2015-01-01

    Background: The identification of the occurrence of falls is an important step for screening and for rehabilitation processes for the elderly. The methods of monitoring these events are susceptible to recording biases, and the choice of the most accurate method remains challenging. Objectives: (i) To investigate the agreement between retrospective self-reporting and prospective monitoring of methods of recording falls, and (ii) to compare the retrospective self-reporting of falls and the prospective monitoring of falls and recurrent falls over a 12-month period among older women at high risk of falls and fractures. Method: A total of 118 community-dwelling older women with low bone density were recruited. The incidence of falls was monitored prospectively in 116 older women (2 losses) via monthly phone calls over the course of a year. At the end of this monitoring period, the older women were asked about their recall of falls in the same 12-month period. The agreement between the two methods was analyzed, and the sensitivity and specificity of self-reported previous falls in relation to the prospective monitoring were calculated. Results: There was moderate agreement between the prospective monitoring and the retrospective self-reporting of falls in classifying fallers (Kappa=0.595) and recurrent fallers (Kappa=0.589). The limits of agreement were 0.35±1.66 falls. The self-reporting of prior falls had a 67.2% sensitivity and a 94.2% specificity in classifying fallers among older women and a 50% sensitivity and a 98.9% specificity in classifying recurrent fallers. Conclusion: Self-reporting of falls over a 12-month period underestimated 32.8% of falls and 50% of recurrent falls. The findings recommend caution if one is considering replacing monthly monitoring with annual retrospective questioning. PMID:26083603

  17. Long-term clinical and economic outcomes in previously untreated paediatric patients with severe haemophilia A: A nationwide real-world study with 700 person-years.

    Science.gov (United States)

    Vepsäläinen, K; Riikonen, P; Lassila, R; Arola, M; Huttunen, P; Lähteenmäki, P; Möttönen, M; Selander, T; Martikainen, J

    2018-03-01

    For previously untreated patients (PUPs) with severe haemophilia A in Finland for the past 2 decades, the standard practice has been to start early primary prophylaxis. We evaluated the long-term clinical outcomes and costs of treatment with high-dose prophylaxis in PUPs from birth to adolescence, including immune tolerance induction (ITI). From the medical records of all PUPs born between June 1994 and May 2013 in Finland, we retrospectively extracted data on clinical outcomes and healthcare use. Using linear mixed models, we analysed longitudinal clinical outcome data. To analyse skewed cost data, including zero costs, we applied hurdle regression. All 62 patients received early regular prophylaxis; totally, they have had treatment for nearly 700 patient-years. The median age of starting home treatment was 1.1 years. The mean (SD) annual treatment costs (€ per kg) were 4391€ (3852). For ages 1-3, ITI comprised over half of the costs; in other groups, prophylactic FVIII treatment dominated. With these high costs, however, clinical outcomes were desirable; median (IQR) ABR was low at 0.19 (0.07-0.46) and so was AJBR at 0.06 (0-0.24). Thirteen (21%) patients developed a clinically significant inhibitor, 10 (16%) with a high titre. All ITIs were successful. The mean costs for ITI were 383 448€ (259 085). The expected ITI payback period was 1.81 (95% CI 0.62-12.12) years. Early high-dose prophylaxis leads to excellent long-term clinical outcomes, and early childhood ITI therapy seems to turn cost-neutral generally already in 2 years. © 2018 John Wiley & Sons Ltd.

  18. Placental complications after a previous cesarean section

    OpenAIRE

    Milošević Jelena; Lilić Vekoslav; Tasić Marija; Radović-Janošević Dragana; Stefanović Milan; Antić Vladimir

    2009-01-01

    Introduction The incidence of cesarean section has been rising in the past 50 years. With the increased number of cesarean sections, the number of pregnancies with the previous cesarean section rises as well. The aim of this study was to establish the influence of the previous cesarean section on the development of placental complications: placenta previa, placental abruption and placenta accreta, as well as to determine the influence of the number of previous cesarean sections on the complic...

  19. Comparative study of the binding of trypsin to caffeine and theophylline by spectrofluorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruiyong, E-mail: wangry@zzu.edu.cn [Department of Chemistry, Zhengzhou University, Zhengzhou 450001 (China); Kang, Xiaohui [Department of Chemistry, Zhengzhou University, Zhengzhou 450001 (China); Wang, Ruiqiang [The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052 (China); Wang, Rui; Dou, Huanjing; Wu, Jing; Song, Chuanjun [Department of Chemistry, Zhengzhou University, Zhengzhou 450001 (China); Chang, Junbiao, E-mail: changjunbiao@zzu.edu.cn [Department of Chemistry, Zhengzhou University, Zhengzhou 450001 (China)

    2013-06-15

    The interactions between trypsin and caffeine/theophylline were investigated by fluorescence spectroscopy, UV–visible absorption spectroscopy, resonance light scattering and synchronous fluorescence spectroscopy under mimic physiological conditions. The results revealed that the fluorescence quenching of trypsin by caffeine and theophylline was the result of the formed complex of caffeine–trypsin and theophylline–trypsin. The binding constants and thermodynamic parameters at three different temperatures were obtained. The hydrophobic interaction was the predominant intermolecular forces to stabilize the complex. Results showed that caffeine was the stronger quencher and bound to trypsin with higher affinity than theophylline. -- Highlights: ► The fluorescence of trypsin can be quenched by caffeine or theophylline via hydrophobic contacts. ► Caffeine binds to trypsin with higher affinity than theophylline. ► The influence of molecular structure on the binding aspects is reported.

  20. A tight binding and [Formula: see text] study of monolayer stanene.

    Science.gov (United States)

    Jiang, Liming; Marconcini, Paolo; Hossian, Md Sharafat; Qiu, Wanzhi; Evans, Robin; Macucci, Massimo; Skafidas, Efstratios

    2017-09-21

    Stanene is a single layer of tin atoms which has been discovered as an emerging material for quantum spin Hall related applications. In this paper, we present an accurate tight-binding model for single layer stanene near the Fermi level. We parameterized the onsite and hopping energies for the nearest, second nearest, and third nearest neighbor tight-binding method, both without and with spin orbital coupling. We derived the analytical solution for the [Formula: see text]and [Formula: see text] points and numerically investigated the buckling effect on the material electronic properties. In these points of the reciprocal space, we also discuss a corresponding [Formula: see text] description, obtaining the value of the [Formula: see text] parameters both analytically from the tight-binding ones, and numerically, fitting the ab-initio dispersion relations. Our models provide a foundation for large scale atomistic device transport calculations.

  1. Comparative study of the binding of trypsin to caffeine and theophylline by spectrofluorimetry

    International Nuclear Information System (INIS)

    Wang, Ruiyong; Kang, Xiaohui; Wang, Ruiqiang; Wang, Rui; Dou, Huanjing; Wu, Jing; Song, Chuanjun; Chang, Junbiao

    2013-01-01

    The interactions between trypsin and caffeine/theophylline were investigated by fluorescence spectroscopy, UV–visible absorption spectroscopy, resonance light scattering and synchronous fluorescence spectroscopy under mimic physiological conditions. The results revealed that the fluorescence quenching of trypsin by caffeine and theophylline was the result of the formed complex of caffeine–trypsin and theophylline–trypsin. The binding constants and thermodynamic parameters at three different temperatures were obtained. The hydrophobic interaction was the predominant intermolecular forces to stabilize the complex. Results showed that caffeine was the stronger quencher and bound to trypsin with higher affinity than theophylline. -- Highlights: ► The fluorescence of trypsin can be quenched by caffeine or theophylline via hydrophobic contacts. ► Caffeine binds to trypsin with higher affinity than theophylline. ► The influence of molecular structure on the binding aspects is reported

  2. Selectivity in Ligand Binding to Uranyl Compounds: A Synthetic, Structural, Thermodynamic and Computational Study

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, John [Univ. of California, Berkeley, CA (United States)

    2017-12-06

    The uranyl cation (UO22+) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. We believe that the goal of developing a practical system for uranium separation from seawater will not be attained without new insights into our existing fundamental knowledge of actinide chemistry. We posit that detailed studies of the kinetic and thermodynamic factors that influence interactions between f-elements and ligands with a range of donor atoms is essential to any major advance in this important area. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. We anticipate that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials.

  3. Docking based 3d-QSAR studies applied at the BRAF inhibitors to understand the binding mechanism

    International Nuclear Information System (INIS)

    Mahmood, U.; Haq, Z.U.

    2011-01-01

    BRAF is a great therapeutic target in a wide variety of human cancers. It is the member of Ras Activating Factor (RAF) family of serine/throenine kinase. The mutated form of the BRAF has diverted all the attention towards itself because of increase severity and elevated kinase activity. The RAF signal transduction cascade is a conserved protein pathway that is involved in cell cycle progression and apoptosis. The ERK regulates phosphorylation of different proteins either in cytosol or in nucleus but disorders in ERK signaling pathway cause mutation in BRAF. This cascade in these cells may provide selection of mutated BRAF in which valine is substituted with glutamatic acid at position 600. This mutation occurs in activation loop. A number of inhibitors reported to target different members of RAF, some of them have potential to target the BRAF as well. Major reason for failure of previously reported inhibitors was due to the highly conserved sequence and confirmation of catalytic cleft which is always a center of consideration for binding of inhibitors to suppress the kinase activity. This is the first attempt to study and understand the BARF inhibitors - protein interactions in detail by utilizing 3D-QSAR and molecular docking techniques. Most reliable techniques of 3D QSAR i.e Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) were applied for three different data sets. The data sets selected for better evaluation of BRAF inhibitors belongs to 2, 6-Disubstituted Pyrazine, Pyridoimidazolones and its derivatives. Our models would offer help to better understand the structure-activity relationships that exist for these classes of compounds and also facilitate the design of novel inhibitors with good chemical diversity. (Author)

  4. TNP-AMP Binding to the Sarcoplasmic Reticulum Ca2+-ATPase Studied by Infrared Spectroscopy

    OpenAIRE

    Liu, Man; Barth, Andreas

    2003-01-01

    Infrared spectroscopy was used to monitor the conformational change of 2′,3′-O-(2,4,6-trinitrophenyl)adenosine 5′-monophosphate (TNP-AMP) binding to the sarcoplasmic reticulum Ca2+-ATPase. TNP-AMP binding was observed in a competition experiment: TNP-AMP is initially bound to the ATPase but is then replaced by β,γ-iminoadenosine 5′-triphosphate (AMPPNP) after AMPPNP release from P3-1-(2-nitrophenyl)ethyl AMPPNP (caged AMPPNP). The resulting infrared difference spectra are compared to those of...

  5. A Comparative Study of the Previously Graduated Dentists' Knowledge versus those Recently Graduated as to Proper Prescription of Interaoral Radiography and Panoramic Views

    OpenAIRE

    Bardal R.; Rahimi R.; Ahmadi Motamayel F.

    2011-01-01

    Statement of Problems: The first step to decrease the patients' exposure to unnecessary radiography radiation is the proper prescription of radiography. . Purpose: The purpose of this study was to evaluate the knowledge of general dental practitioners as to proper prescription of intraoral radiography and panoramic views. Materials and Method: In this study, a questionnaire on the dentists' knowledge about the proper prescription of dental radiography was used. A total of eighty one general d...

  6. The change in motivating factors influencing commencement, adherence and retention to a supervised resistance training programme in previously sedentary post-menopausal women: a prospective cohort study.

    Science.gov (United States)

    Viljoen, Janet Erica; Christie, Candice Jo-Anne

    2015-03-12

    Understanding motivators for exercise participation in post-menopausal women may impact retention to exercise programmes and inform intervention trial designs. The purpose of this investigation was to assess self-reported motivational factors influencing adherence and retention to a 24-week progressive resistance training programme. Post-menopausal females (n = 34) were passively recruited to undertake a 24-week progressive resistance training protocol, in small-group sessions, on three non-consecutive days of the week. Attendance was recorded by the researcher. Qualitative reports were sourced from the sample for four phases of the study: pre-study (prior to week 1), recruitment (week 1), during study (weeks 2 - 24), and post-intervention (beyond week 24). Responses were categorised according to ten descriptors: specific health index improvement, education, flexibility of time, social contact, conscience (loyalty to the researcher), wellness, weight management, organisation parameters (pertaining to the study programme) and enjoyment of the exercises. Of the initial sample, 76.5% (n = 26) met the specified ≥80% attendance criterion. The primary findings were that motivation to volunteer for the study was driven by a perceived need for a structured exercise programme (50% of respondents). A commitment to the researcher was the primary motivator for continued adherence to the study for 50% of participants. Social contact with other participants was cited by 60% of the sample as the primary reason for adherence for the full duration of 24 weeks. A desire to maintain the "wellness" derived from the programme was cited by 60% as a reason for continuing an exercise routine post-study. This study identified that routine and supervision initially attract women to exercise programmes, while social cohesion of the group setting contributes to retention over time. Understanding the changing nature of motivating factors may contribute to better overall adherence

  7. Apoferritin-based nanomedicine platform for drug delivery: equilibrium binding study of daunomycin with DNA

    Energy Technology Data Exchange (ETDEWEB)

    Ma Ham, Aihui; Wu, Hong J.; Wang, Jun; Kang, Xinhuang; Zhang, Youyu; Lin, Yuehe

    2011-05-11

    Apoferritin is a nanostructured material with a uniform size and spherical structure, and it has excellent bio-compatibility. In this work, we report the use of apoferritin as a novel and biocompatible carrier for stabilizing enzymes and their activities. We used glucose oxidase (GOx) as a model enzyme. GOx was immobilized on the surface of the apoferritin through a green synthetic approach taking advantage of bioaffinity binding between streptavidin and biotin. As a result, a glucose oxidase-biotin/streptavidin/biotin-apoferritin conjugate (Apo-GOx) was prepared using streptavidin as a bridge. The synthesized Apo-GOx was characterized with transmission electron microscopy, ultraviolet, and fluorescence spectroscopy. The activity and stability of GOx on the surface of the apoferritin were studied in different environments, such as temperature, chemicals, and pH, in comparison with the biotinylated GOx (B-GOx). The results showed that the activity of GOx on the apoferritin surface was significantly enhanced. The thermal and chemical stability of the GOx on the apoferritin was also greatly improved compared to free B-GOx in a solution. It was found that the activity of the GOx on the apoferritin only lost 30% in comparison to a 70% loss of free B-GOx after a 2-hr incubation at 50oC. There was almost no decrease in activity for the GOx on the apoferritin as compared to an 80% activity decrease for free B-GOx after 30 minutes of incubation in a 5 M urea solution. The GOx immobilized apoferritin nanoparticles exhibited high sensitivity for glucose detection with a detection limit of 3 nM glucose. This work offers a novel approach for immobilizing enzymes with enhanced stability and activity, and this method may find a number of applications, such as in catalysis and bioassys/biosensors.

  8. Vanadium-binding protein in a vanadium-rich ascidian Ascidia sydneiensissamea: CW and pulsed EPR studies.

    Science.gov (United States)

    Fukui, Kôichi; Ueki, Tatsuya; Ohya, Hiroaki; Michibata, Hitoshi

    2003-05-28

    Some of the ascidians belonging to the suborder Phlebobranchia accumulate vanadium ion efficiently from seawater. Clarification of the mechanism of this surprisingly efficient metal-accumulation system is desirable. Two mutually similar vanadium-binding proteins (vanabin1 and vanabin2) have recently been isolated from a vanadium-rich ascidian Ascidia sydneiensis samea. In this study, the vanadium-binding properties of vanabin2 have been investigated by X-band CW EPR and pulsed EPR spectroscopy. CW EPR spectra of samples containing various ratios of VO2+ and vanabin2 invariably exhibited a usual mononuclear-type VO2+ EPR signal with the intensity dependent on the ratio [vanabin]/[V]. EPR titration has shown that vanabin2 can bind up to approximately 23.9 vanadium ions per one molecule, almost all of which ( approximately 84%) are in a mononuclear VO2+ state as estimated by EPR quantitation. Electron spin-echo envelope modulation (ESEEM) spectra of VO-vanabin2 exhibited reasonably intense peaks attributable to amine nitrogen. This is consistent with the fact that vanabin2 is a lysine-rich protein (14 lysines out of 91 amino acids). The present study reveals the uniqueness of vanabin2, which can bind a large number of metal ions in a mononuclear fashion in contrast to the situation for ferritin and metallothionein.

  9. Systematic Synthesis and Binding Study of HIV V3 Glycopeptides Reveal the Fine Epitopes of Several Broadly Neutralizing Antibodies.

    Science.gov (United States)

    Orwenyo, Jared; Cai, Hui; Giddens, John; Amin, Mohammed N; Toonstra, Christian; Wang, Lai-Xi

    2017-06-16

    A class of new glycan-reactive broadly neutralizing antibodies represented by PGT121, 10-1074, and PGT128 has recently been discovered that targets specific N-glycans and the peptide region around the V3 domain. However, the glycan specificity and fine epitopes of these bNAbs remain to be further defined. We report here a systematic chemoenzymatic synthesis of homogeneous V3 glycopeptides derived from the HIV-1 JR-FL strain carrying defined N-glycans at N332, N301, and N295 sites. Antibody binding studies revealed that both the nature and site of glycosylation in the context of the V3 domain were critical for high-affinity binding. It was found that antibody PGT128 exhibited specificity for high-mannose N-glycan with glycosylation site promiscuity, PGT121 showed binding specificity for glycopeptide carrying a sialylated N-glycan at N301 site, and 10-1074 was specific for glycopeptide carrying a high-mannose N-glycan at N332 site. The synthesis and binding studies permit a detailed assessment of the glycan specificity and the requirement of peptide in the context of antibody-antigen recognition. The identified glycopeptides can be used as potential templates for HIV vaccine design.

  10. Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics

    Directory of Open Access Journals (Sweden)

    Gowda Veerabasappa T

    2007-12-01

    Full Text Available Abstract Background The snake venom group IIA secreted phospholipases A2 (SVPLA2, present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL at the membrane/water interface and by highly specific direct binding to: (i presynaptic membrane-bound or intracellular receptors; (ii natural PLA2-inhibitors from snake serum; and (iii coagulation factors present in human blood. Results Using surface plasmon resonance (SPR protein-protein interaction measurements and an in vitro biological test of inhibition of prothrombinase activity, we identify a number of Viperidae venom SVPLA2s that inhibit blood coagulation through direct binding to human blood coagulation factor Xa (FXa via a non-catalytic, PL-independent mechanism. We classify the SVPLA2s in four groups, depending on the strength of their binding. Molecular electrostatic potentials calculated at the surface of 3D homology-modeling models show a correlation with inhibition of prothrombinase activity. In addition, molecular docking simulations between SVPLA2 and FXa guided by the experimental data identify the potential FXa binding site on the SVPLA2s. This site is composed of the following regions: helices A and B, the Ca2+ loop, the helix C-β-wing loop, and the C-terminal fragment. Some of the SVPLA2 binding site residues belong also to the interfacial binding site (IBS. The interface in FXa involves both, the light and heavy chains. Conclusion We have experimentally identified several strong FXa-binding SVPLA2s that disrupt the function of the coagulation cascade by interacting with FXa by the non-catalytic PL-independent mechanism. By theoretical methods we mapped the interaction sites on both, the SVPLA2s and FXa. Our findings may lead to the design of novel, non-competitive FXa inhibitors.

  11. The possibility of previous epidemiological data to serve as baseline for future national oral health surveys--a study in Vietnam.

    NARCIS (Netherlands)

    Palenstein Helderman, W.H. van; Truin, G.J.; Can, N.; Khanh, N.D.

    2001-01-01

    AIM: The purpose of this paper is to review the most recent epidemiological data (1985-2000) on dental caries and periodontal diseases in Vietnam in an attempt to obtain a 'baseline' for future national oral health surveys. METHODS: Studies on periodontal diseases and caries were included when CPITN

  12. Does hyperbaric oxygen treatment have the potential to increase salivary flow rate and reduce xerostomia in previously irradiated head and neck cancer patients? A pilot study

    DEFF Research Database (Denmark)

    Forner, Lone; Hansen, Ole Hyldegaard; von Brockdorff, Annet Schack

    2011-01-01

    Irradiated head and neck cancer survivors treated in the Hyperbaric Oxygen (HBO) Unit, Copenhagen University Hospital, spontaneously reported improvement of radiation-induced dry mouth feeling. The aim of this pilot study was to evaluate salivary flow rate and xerostomia before and after HBO...

  13. Studies on ATP-diphosphohydrolase nucleotide-binding sites by intrinsic fluorescence

    Directory of Open Access Journals (Sweden)

    A.M. Kettlun

    2000-07-01

    Full Text Available Potato apyrase, a soluble ATP-diphosphohydrolase, was purified to homogeneity from several clonal varieties of Solanum tuberosum. Depending on the source of the enzyme, differences in kinetic and physicochemical properties have been described, which cannot be explained by the amino acid residues present in the active site. In order to understand the different kinetic behavior of the Pimpernel (ATPase/ADPase = 10 and Desirée (ATPase/ADPase = 1 isoenzymes, the nucleotide-binding site of these apyrases was explored using the intrinsic fluorescence of tryptophan. The intrinsic fluorescence of the two apyrases was slightly different. The maximum emission wavelengths of the Desirée and Pimpernel enzymes were 336 and 340 nm, respectively, suggesting small differences in the microenvironment of Trp residues. The Pimpernel enzyme emitted more fluorescence than the Desirée apyrase at the same concentration although both enzymes have the same number of Trp residues. The binding of the nonhydrolyzable substrate analogs decreased the fluorescence emission of both apyrases, indicating the presence of conformational changes in the neighborhood of Trp residues. Experiments with quenchers of different polarities, such as acrylamide, Cs+ and I- indicated the existence of differences in the nucleotide-binding site, as further shown by quenching experiments in the presence of nonhydrolyzable substrate analogs. Differences in the nucleotide-binding site may explain, at least in part, the kinetic differences of the Pimpernel and Desirée isoapyrases.

  14. In-vitro binding assay study of 99mTc-flouroquinolones with E. coli ...

    African Journals Online (AJOL)

    Muhammad Abdul Qadir

    2014-10-28

    Oct 28, 2014 ... Abstract A simple methodology was developed to evaluate binding efficiency of antibiotic mem- bers of fluoroquinolones, namely ciprofloxacin, ofloxacin and enorfloxacin, complexed with 99mTc, against Escherichia coli, Salmonella and Pseudomonas aeruginosa bacterial strains. Radioactivity in the pellet ...

  15. The penicillin-binding protein 4 of Escherichia coli : primary structure, biochemical and genetic studies

    NARCIS (Netherlands)

    Mottl, Harald

    1992-01-01

    De ß-lactam antibiotica ("de penicillines") zijn zowel in medisch als ecomisch opzicht de belangrijkste groep antibiotica: De werking van deze antibiotica berust op verstoring van de synthese van de bacteriele celwand. De doeleiwitten van deze antibiotica worden penicillin-binding proteins, kortweg

  16. Modulation of [3H]-glutamate binding by serotonin in the rat hippocampus: An autoradiographic study

    International Nuclear Information System (INIS)

    Mennini, T.; Miari, A.

    1991-01-01

    Serotonin (5-HT) added in vitro increased [ 3 H]-glutamate specific binding in the rat hippocampus, reaching statistical significance in layers rich in N-Methyl-D-Aspartate sensitive glutamate receptors. This effect was explained by a significant increase in the apparent affinity of [ 3 H]-glutamate when 5-HT is added in vitro. Two days after lesion of serotonergic afferents to the hippocampus with 5,7- Dihydroxytryptamine [ 3 H]-glutamate binding was significantly decreased in the CA3 region and stratum lacunosum moleculare of the hippocampus, this reduction being reversed by in vitro addition of 10 μM 5-HT. The decrease observed is due to a significant reduction of quisqualate-insensitive (radiatum CA3) and kainate receptors (strata oriens, radiatum, pyramidal of CA3). Five days after lesion [ 3 H]-glutamate binding increased significantly in the CA3 region of the hippocampus but was not different from sham animals in the other hippocampal layers. Two weeks after lesion [ 3 H]-glutamate binding to quisqualate-insensitive receptors was increased in all the hippocampal layers, while kainate and quisqualate-sensitive receptors were not affected. These data are consistent with the possibility that 5-HT is a direct positive modulator of glutamate receptor subtypes

  17. Studies on the Binding of Lead and Zinc Ions by Modified Cellulosic ...

    African Journals Online (AJOL)

    substrate contact time, the metal ion concentration, the metal ion type and the substrate type. The amount of these ions absorbed varies with the cellulosic material and in the order Pb (II) > Zn (II). It is shown that the cellulosic materials could bind ...

  18. In-vitro binding assay study of 99m Tc-flouroquinolones with E. coli ...

    African Journals Online (AJOL)

    A simple methodology was developed to evaluate binding efficiency of antibiotic members of fluoroquinolones, namely ciprofloxacin, ofloxacin and enorfloxacin, complexed with 99mTc, against Escherichia coli, Salmonella and Pseudomonas aeruginosa bacterial strains. Radioactivity in the pellet, tips supernatant and ...

  19. Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

    Directory of Open Access Journals (Sweden)

    Artur Jabłoński

    2017-11-01

    Full Text Available Fluorescent pyrene–linker–nucleobase (nucleobase = thymine, adenine conjugates with carbonyl and hydroxy functionalities in the linker were synthesized and characterized. X-ray single-crystal structure analysis performed for the pyrene–C(OCH2CH2–thymine (2 conjugate reveals dimers of molecules 2 stabilized by hydrogen bonds between the thymine moieties. The photochemical characterization showed structure-dependent fluorescence properties of the investigated compounds. The conjugates bearing a carbonyl function represent weak emitters as compared to compounds with a hydroxy function in the linker. The self-assembly properties of pyrene nucleobases were investigated in respect to their binding to single and double strand oligonucleotides in water and in buffer solution. In respect to the complementary oligothymidine T10 template in water, compounds 3 and 5 both show a self-assembling behavior according to canonical base–base pairing. However, in buffer solution, derivative 5 was much more effective than 3 in binding to the T10 template. Furthermore the adenine derivative 5 binds to the double-stranded (dA10–T10 template with a self-assembly ratio of 112%. Such a high value of a self-assembly ratio can be rationalized by a triple-helix-like binding, intercalation, or a mixture of both. Remarkably, compound 5 also shows dual staining pattern in living HeLa cells. Confocal microscopy confirmed that 5 predominantly stains mitochondria but it also accumulates in the nucleoli of the cells.

  20. Alfalfa (Medicago sativa L.) is tolerant to higher levels of salinity than previous guidelines indicated: Implications of field and greenhouse studies

    Science.gov (United States)

    Putnam, Daniel H.; Benes, Sharon; Galdi, Giuliano; Hutmacher, Bob; Grattan, Steve

    2017-04-01

    Alfalfa (Medicago sativa L.) is the most widely grown leguminous forage crop in North America and is valued for high productivity, quality, economic value, and for dairy productivity. Alfalfa has historically been classified as moderately sensitive to saline conditions, with yield declines predicted at >2 dS/m in the saturated soil paste extract. However, greenhouse, sand tank, and field studies over the past five years have confirmed that alfalfa can be grown with limited negative effects at much higher salinity levels. A broad collection of alfalfa varieties has exhibited a range of resistance at irrigation water salinities >5 dS/m ECw in greenhouse trials, with significant variation due to variety. USDA-ARS sand tank studies indicated similar or greater tolerances closer to 8 dS/m in the soil water, in addition to confirmation of significant varietal differences. A three-year field study on clay loam soil with applications of 5-7 dS/m ECw irrigation water indicated normal yields and excellent stand survivability. A second field study in the same soil type with levels from 8-10 dS/m ECw showed yield reductions of 10-15% but economic yields were still achieved at those levels. Field and greenhouse studies were conducted with mixed salt saline sodic waters typical of the San Joaquin Valley of California. Field evaluation of variety performance was subject to greater variation due to secondary salinity-soil interactions including water infiltration and crusting problems, not only salinity per-se. Thus, adequate irrigation water availability to the crop may be as important as salinity in impacting yields under field conditions. Once established, the deep-rooted characteristics of alfalfa enable utilization of deeper subsurface moisture, even at moderate to high salinity levels, as documented by USDA lysimeter studies. Significant advantages to salinity-tolerant varieties have been observed. It will be important to consider specific management factors which may enable

  1. Flow rate and interference studies for copper binding to a silica-immobilized humin polymer matrix: column and batch experiments.

    Science.gov (United States)

    Gardea-Torresdey, Jorge L; Contreras, Carolina; de la Rosa, Guadalupe; Peralta-Videa, Jose R

    2005-01-01

    Batch and column experiments were performed to determine the Cu(II) binding capacity of silica-immobilized humin biomass. For column studies, 500 bed volumes of a 0.1 mM Cu(II) solution were passed through humin packed columns at the flow rates of 1, 1.5, 2, and 3 mL/min. The biopolymer showed an average Cu binding capacity of 12 +/- 1.5 mg/g and a Cu recovery of about 96.5 % +/- 1.5. The breakthrough points for Cu(II) alone were approximately 420, 390, 385, and 300 bed volumes for the flow rates of 1, 1.5, 2 and 3 mL/min, respectively. The interference studies demonstrated that at low concentrations, the hard cations Ca(II) and Mg(II) did not seem to represent a major interference on Cu(II) binding to the humin biopolymer. The selectivity showed by this biopolymer was Cu(II)>Ca(II)>Mg(II). On the other hand, batch experiments showed that Ca(II) + Mg(II) at 100mM each reduced the Cu(II) binding to 73 %. However, 1000 mM concentrations of Ca(II) and Mg(II), separately and in mixture, reduced the Cu(II) binding to 47 %, 44 % and 31 %, respectively. The results of this study showed that immobilized humin in a silica matrix could represent an inexpensive bio-source for Cu removal from contaminated water, even in the presence of low concentrations of the hard cations Ca(II) and Mg(II).

  2. Effect of benzalkonium chloride?free travoprost on intraocular pressure and ocular surface symptoms in patients with glaucoma previously on latanoprost: an open-label study

    OpenAIRE

    Lopes, Joao F.; Hubatsch, Douglas A.; Amaris, Patricia

    2015-01-01

    Background Prostaglandin analogs reduce intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension; however, these medications may affect the ocular surface and elicit ocular discomfort when preserved with benzalkonium chloride (BAK). Methods This was an open-label, single-arm study conducted in Latin America from February 2012 to May 2013. Patients with open-angle glaucoma or ocular hypertension who were intolerant of latanoprost 0.005?% were transitioned to recei...

  3. Competitive binding of phenylbutazone and colchicine to serum albumin in multidrug therapy: A spectroscopic study

    Science.gov (United States)

    Sułkowska, A.; Maciążek-Jurczyk, M.; Bojko, B.; Równicka, J.; Zubik-Skupień, I.; Temba, E.; Pentak, D.; Sułkowski, W. W.

    2008-06-01

    The binding sites for phenylbutazone and colchicine were identified in tertiary structure of bovine and human serum albumin with the use of spectrofluorescence analysis. It was found that phenylbutazone has two binding sites in both sera albumins (HSA and BSA), while colchicine has one binding site in BSA as well as in HSA. The comparison of the quenching effect of BSA and HSA fluorescence by phenylbutazone and colchicine allows us to identify subdomain IIA in protein as the binding site for these two drugs. In this subdomain tryptophan 214 is located. The participation of tyrosyl and tryptophanyl residues of protein was also estimated in the drug-albumin complex. The comparison of quenching of fluorescence of HSA and BSA excited at 280 nm with that at 295 nm allowed us to state that the participation of tyrosyl residues of albumin in the phenylbutazone-serum albumin interaction is significant. The analysis of quenching of fluorescence of BSA in the binary and ternary systems showed that phenylbutazone does not affect the complex formed between colchicine and BSA. Similarly, colchicine has no effect on the Phe-BSA complex. However marked differences were observed for the complex with HSA. On the basis of Ka and KQ values it was concluded that colchicine may probably cause displacement of phenylbutazone from its complex with serum albumin (SA). Static and dynamic quenching for the binary and ternary systems is also discussed. The competition of phenylbutazone and colchicine in binding to serum albumin should be taken into account in the multi-drug therapy.

  4. A multicenter phase I/II study of obatoclax mesylate administered as a 3- or 24-hour infusion in older patients with previously untreated acute myeloid leukemia.

    Directory of Open Access Journals (Sweden)

    Aaron D Schimmer

    Full Text Available An open-label phase I/II study of single-agent obatoclax determined a maximum tolerated dose (MTD and schedule, safety, and efficacy in older patients (≥ 70 yr with untreated acute myeloid leukemia (AML.Phase I evaluated the safety of obatoclax infused for 3 hours on 3 consecutive days (3 h × 3 d in 2-week cycles. Initial obatoclax dose was 30 mg/day (3 h × 3 d; n = 3. Obatoclax was increased to 45 mg/day (3 h × 3 d if ≤ 1 patient had a dose-limiting toxicity (DLT and decreased to 20 mg/day (3 h × 3 d if DLT occurred in ≥ 2 patients. In the phase II study, 12 patients were randomized to receive obatoclax at the dose identified during phase I (3 h × 3 d or 60 mg/day administered by continuous infusion over 24 hours for 3 days (24 h × 3 d to determine the morphologic complete response rate.In phase I, two of three patients receiving obatoclax 30 mg/day (3 h × 3 d experienced grade 3 neurologic DLTs (confusion, ataxia, and somnolence. Obatoclax was decreased to 20 mg/day (3 h × 3 d. In phase II, no clinically relevant safety differences were observed between the 20 mg/day (3 h × 3 d; n = 7 and 60 mg/day (24 h × 3 d; n = 5 arms. Neurologic and psychiatric adverse events were most common and were generally transient and reversible. Complete response was not achieved in any patient.Obatoclax 20 mg/day was the MTD (3 h × 3 d in older patients with AML. In the schedules tested, single-agent obatoclax was not associated with an objective response. Evaluation in additional subgroups or in combination with other chemotherapy modalities may be considered for future study.ClinicalTrials.gov NCT00684918.

  5. A multicenter phase I/II study of obatoclax mesylate administered as a 3- or 24-hour infusion in older patients with previously untreated acute myeloid leukemia.

    Science.gov (United States)

    Schimmer, Aaron D; Raza, Azra; Carter, Thomas H; Claxton, David; Erba, Harry; DeAngelo, Daniel J; Tallman, Martin S; Goard, Carolyn; Borthakur, Gautam

    2014-01-01

    An open-label phase I/II study of single-agent obatoclax determined a maximum tolerated dose (MTD) and schedule, safety, and efficacy in older patients (≥ 70 yr) with untreated acute myeloid leukemia (AML). Phase I evaluated the safety of obatoclax infused for 3 hours on 3 consecutive days (3 h × 3 d) in 2-week cycles. Initial obatoclax dose was 30 mg/day (3 h × 3 d; n = 3). Obatoclax was increased to 45 mg/day (3 h × 3 d) if ≤ 1 patient had a dose-limiting toxicity (DLT) and decreased to 20 mg/day (3 h × 3 d) if DLT occurred in ≥ 2 patients. In the phase II study, 12 patients were randomized to receive obatoclax at the dose identified during phase I (3 h × 3 d) or 60 mg/day administered by continuous infusion over 24 hours for 3 days (24 h × 3 d) to determine the morphologic complete response rate. In phase I, two of three patients receiving obatoclax 30 mg/day (3 h × 3 d) experienced grade 3 neurologic DLTs (confusion, ataxia, and somnolence). Obatoclax was decreased to 20 mg/day (3 h × 3 d). In phase II, no clinically relevant safety differences were observed between the 20 mg/day (3 h × 3 d; n = 7) and 60 mg/day (24 h × 3 d; n = 5) arms. Neurologic and psychiatric adverse events were most common and were generally transient and reversible. Complete response was not achieved in any patient. Obatoclax 20 mg/day was the MTD (3 h × 3 d) in older patients with AML. In the schedules tested, single-agent obatoclax was not associated with an objective response. Evaluation in additional subgroups or in combination with other chemotherapy modalities may be considered for future study. ClinicalTrials.gov NCT00684918.

  6. Effect of benzalkonium chloride-free travoprost on intraocular pressure and ocular surface symptoms in patients with glaucoma previously on latanoprost: an open-label study.

    Science.gov (United States)

    Lopes, Joao F; Hubatsch, Douglas A; Amaris, Patricia

    2015-11-12

    Prostaglandin analogs reduce intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension; however, these medications may affect the ocular surface and elicit ocular discomfort when preserved with benzalkonium chloride (BAK). This was an open-label, single-arm study conducted in Latin America from February 2012 to May 2013. Patients with open-angle glaucoma or ocular hypertension who were intolerant of latanoprost 0.005 % were transitioned to receive once-daily BAK-free travoprost 0.004 % containing polyquaternium-1 (Travatan® preserved with POLYQUAD® [PQ], Alcon Laboratories, Inc; Fort Worth, TX) for 12 weeks. Mean change in IOP from baseline (primary efficacy endpoint) and the percentage of patients who achieved a target IOP of ≤18 mmHg were evaluated at all on-therapy visits. Ocular hyperemia, patient preference, and self-projected adherence were assessed at week 12. Adverse events (AEs) were monitored throughout the study. All enrolled patients were included in the analysis (n = 191); the majority of patients (90.6 %, n = 173/191) completed the study. Mean (SD) patient age was 67.5 (11.3) years, and mean baseline IOP was 14.8 mmHg. Mean IOP was reduced by 0.94 mmHg at week 6 and by 1.09 mmHg at week 12 (P glaucoma or ocular hypertension who were intolerant of latanoprost. BAK-free travoprost 0.004 % is a viable alternative for patients who require switching their IOP-lowering medications because of tolerability issues. ClinicalTrials.gov identifier, NCT01510145.

  7. DNA binding, photo-induced DNA cleavage and cytotoxicity studies of lomefloxacin and its transition metal complexes

    Science.gov (United States)

    Ragheb, Mohamed A.; Eldesouki, Mohamed A.; Mohamed, Mervat S.

    2015-03-01

    This work was focused on a study of the DNA binding and cleavage properties of lomefloxacin (LMF) and its ternary transition metal complexes with glycine. The nature of the binding interactions between compounds and calf thymus DNA (CT-DNA) was studied by electronic absorption spectra, fluorescence spectra and thermal denaturation experiments. The obtained results revealed that LMF and its complexes could interact with CT-DNA via partial/moderate intercalative mode. Furthermore, the DNA cleavage activities of the compounds were investigated by gel electrophoresis. Mechanistic studies of DNA cleavage suggest that singlet oxygen (1O2) is likely to be the cleaving agent via an oxidative pathway, except for Cu(II) complex which proceeds via both oxidative and hydrolytic pathways. Antimicrobial and antitumor activities of the compounds were also studied against some kinds of bacteria, fungi and human cell lines.

  8. Tendon Length, Calf Muscle Atrophy, and Strength Deficit After Acute Achilles Tendon Rupture: Long-Term Follow-up of Patients in a Previous Study.

    Science.gov (United States)

    Heikkinen, Juuso; Lantto, Iikka; Piilonen, Juuso; Flinkkilä, Tapio; Ohtonen, Pasi; Siira, Pertti; Laine, Vesa; Niinimäki, Jaakko; Pajala, Ari; Leppilahti, Juhana

    2017-09-20

    In this prospective study, we used magnetic resonance imaging (MRI) to assess long-term Achilles tendon length, calf muscle volume, and muscle fatty degeneration after surgery for acute Achilles tendon rupture. From 1998 to 2001, 60 patients at our center underwent surgery for acute Achilles tendon rupture followed by early functional postoperative rehabilitation. Fifty-five patients were reexamined after a minimum duration of follow-up of 13 years (mean, 14 years), and 52 of them were included in the present study. Outcome measures included Achilles tendon length, calf muscle volume, and fatty degeneration measured with MRI of both the affected and the uninjured leg. The isokinetic plantar flexion strength of both calves was measured and was correlated with the structural findings. The Achilles tendon was, on average, 12 mm (95% confidence interval [CI] = 8.6 to 15.6 mm; p muscles were 63 cm (13%; p muscle atrophy. Increased Achilles tendon length is associated with smaller calf muscle volumes and persistent plantar flexion strength deficits after surgical repair of Achilles tendon rupture. Strength deficits and muscle volume deficits are partly compensated for by FHL hypertrophy, but 11% to 13% deficits in soleus and gastrocnemius muscle volumes and 12% to 18% deficits in plantar flexion strength persist even after long-term follow-up. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

  9. Outcomes following detection of low level plasma HIV RNA in HIV-infected patients previously virologically suppressed on antiretroviral therapy: a retrospective observational study.

    Science.gov (United States)

    Warren, Annabelle M; Cheng, Allen C; Watson, Kerrie; Lewin, Sharon R; Hoy, Jennifer F

    2017-06-01

    Progressively sensitive assays for plasma HIV RNA have led to increased detection of plasma HIV RNA between 20 and 200 copies/ml, known as low level viremia (LLV) when recurrent or persistent, in HIV-infected patients on antiretroviral therapy (ART). The aim of this study was to determine outcomes following initial detection of LLV in an Australian cohort. A retrospective study using the HIV Service Database (Alfred Hospital) included all patients on ART who recorded plasma HIV RNA 20-200 copies/mL following prior virological suppression (viral load (VL) HIV RNA 200 copies/mL. Factors associated with LLV included co-morbid type 2 diabetes, shorter prior virological suppression and lower nadir CD4 cell count. Clinician management of VL 20-200 copies/mL was generally conservative, with infrequent requests for genotypic analysis (3.3% cases) or change in ART (<1% cases). LLV following virological suppression is common, and occurred as an isolated viral blip in half the patients. Those patients with persistent or recurrent LLV had higher rates of type 2 diabetes, shorter prior virological suppression and lower nadir CD4 cell count.

  10. Comparison of the Binding of Reversible Inhibitors to Human Butyrylcholinesterase and Acetylcholinesterase: A Crystallographic, Kinetic and Calorimetric Study

    Directory of Open Access Journals (Sweden)

    Terrone L. Rosenberry

    2017-11-01

    Full Text Available Acetylcholinesterase (AChE and butyrylcholinesterase (BChE hydrolyze the neurotransmitter acetylcholine and, thereby, function as coregulators of cholinergic neurotransmission. Although closely related, these enzymes display very different substrate specificities that only partially overlap. This disparity is largely due to differences in the number of aromatic residues lining the active site gorge, which leads to large differences in the shape of the gorge and potentially to distinct interactions with an individual ligand. Considerable structural information is available for the binding of a wide diversity of ligands to AChE. In contrast, structural data on the binding of reversible ligands to BChE are lacking. In a recent effort, an inhibitor competition approach was used to probe the overlap of ligand binding sites in BChE. Here, we extend this study by solving the crystal structures of human BChE in complex with five reversible ligands, namely, decamethonium, thioflavin T, propidium, huprine, and ethopropazine. We compare these structures to equivalent AChE complexes when available in the protein data bank and supplement this comparison with kinetic data and observations from isothermal titration calorimetry. This new information now allows us to define the binding mode of various ligand families and will be of importance in designing specific reversible ligands of BChE that behave as inhibitors or reactivators.

  11. Study of the role of bran water binding and the steric hindrance by bran in straight dough bread making.

    Science.gov (United States)

    Hemdane, S; Langenaeken, N A; Jacobs, P J; Verspreet, J; Delcour, J A; Courtin, C M

    2018-07-01

    This study investigates the effect of the physical presence and water binding of wheat bran during bread making, and the possible mechanisms behind this effect. Regular bran, pericarp-enriched bran and synthetic bran-like particles with different water binding capacities and particle sizes were used. Incorporation of regular and pericarp-enriched bran in dough (15% dm) led to a lower oven rise than the control dough. Bread volumes decreased with 11% and 30%, respectively. Dough with synthetic bran, having a low water binding capacity, displayed a near to normal leavening and oven rise and resulted in a bread volume decrease of only 5% compared to the control. Particle size reduction of regular bran and synthetic bran to an average size of 200 µm did not affect final bread quality. Results indicate that water binding by bran affects bread quality the most, whereas steric hindrance by physical presence of bran particles is less determinative. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Studies with doxazosin on the saturable binding of 125I-LDL by liver in normocholesterolemic mice

    International Nuclear Information System (INIS)

    Nanjee, M.N.; Miller, N.E.

    1987-01-01

    Tissue culture studies have provided evidence that alpha 1-adrenergic receptor inhibition with doxazosin increases the number of low-density lipoprotein (LDL) receptors in human fibroblasts. A similar effect occurring in vivo might explain the reduction of plasma LDL concentration observed in some clinical trials of prazosin. In order to examine this question further, mice were given doxazosin 100 or 400 micrograms/kg/day by i.p. injection for 4 days, after which they were killed, blood was collected and livers were excised. Binding of 125 I-labelled human LDL to tissue homogenates, over the concentration range 30-120 micrograms LDL protein/ml, was measured at 37 degrees C in the absence and presence of excess unlabelled LDL. Woolf plots of the results for saturable binding were found to be compatible with a single class of binding site. In control animals Bmax for this receptor was 867 +/- 117 ng LDL protein/mg tissue protein, and the equilibrium dissociation constant was 32.7 +/- 6.6 micrograms LDL protein/ml (mean +/- SD, n = 5). Doxazosin treatment had no effect on either parameter of 125 I-LDL binding. A trend towards a decrease in liver triglyceride concentration with increasing doses of doxazosin was recorded, but there was no evidence for effects on liver cholesterol or serum lipid concentrations

  13. Spectroscopic studies on the binding interaction of phenothiazinium dyes, azure A and azure B to double stranded RNA polynucleotides.

    Science.gov (United States)

    Khan, Asma Yasmeen; Suresh Kumar, Gopinatha

    2016-01-05

    This manuscript presents spectroscopic characterization of the interaction of two phenothiazinium dyes, azure A and azure B with double stranded (ds) ribonucleic acids, poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C). Absorbance and fluorescence studies revealed that these dyes bind to the RNAs with binding affinities of the order 10(6)M(-1) to poly(A).poly(U), and 10(5)M(-1) to poly(C).poly(G) and poly(I).poly(C), respectively. Fluorescence quenching and viscosity data gave conclusive evidence for the intercalation of the dyes to these RNA duplexes. Circular dichroism results suggested that the conformation of the RNAs was perturbed on interaction and the dyes acquired strong induced optical activity on binding. Azure B bound to all the three RNAs stronger than azure A and the binding affinity varied as poly(A).poly(U)>poly(C).poly(G)>poly(I).poly(C) for both dyes. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. pH-tuneable binding of 2′-phospho-ADP-ribose to ketopantoate reductase: a structural and calorimetric study

    Energy Technology Data Exchange (ETDEWEB)

    Ciulli, Alessio [University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Lobley, Carina M. C. [Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Tuck, Kellie L. [University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Smith, Alison G. [Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA (United Kingdom); Blundell, Tom L. [Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Abell, Chris, E-mail: ca26@cam.ac.uk [University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2007-02-01

    A combined crystallographic, calorimetric and mutagenic study has been used to show how changes in pH give rise to two distinct binding modes of 2′-phospho-ADP-ribose to ketopantoate reductase. The crystal structure of Escherichia coli ketopantoate reductase in complex with 2′-monophosphoadenosine 5′-diphosphoribose, a fragment of NADP{sup +} that lacks the nicotinamide ring, is reported. The ligand is bound at the enzyme active site in the opposite orientation to that observed for NADP{sup +}, with the adenine ring occupying the lipophilic nicotinamide pocket. Isothermal titration calorimetry with R31A and N98A mutants of the enzyme is used to show that the unusual ‘reversed binding mode’ observed in the crystal is triggered by changes in the protonation of binding groups at low pH. This research has important implications for fragment-based approaches to drug design, namely that the crystallization conditions and the chemical modification of ligands can have unexpected effects on the binding modes.

  15. pH-tuneable binding of 2′-phospho-ADP-ribose to ketopantoate reductase: a structural and calorimetric study

    International Nuclear Information System (INIS)

    Ciulli, Alessio; Lobley, Carina M. C.; Tuck, Kellie L.; Smith, Alison G.; Blundell, Tom L.; Abell, Chris

    2007-01-01

    A combined crystallographic, calorimetric and mutagenic study has been used to show how changes in pH give rise to two distinct binding modes of 2′-phospho-ADP-ribose to ketopantoate reductase. The crystal structure of Escherichia coli ketopantoate reductase in complex with 2′-monophosphoadenosine 5′-diphosphoribose, a fragment of NADP + that lacks the nicotinamide ring, is reported. The ligand is bound at the enzyme active site in the opposite orientation to that observed for NADP + , with the adenine ring occupying the lipophilic nicotinamide pocket. Isothermal titration calorimetry with R31A and N98A mutants of the enzyme is used to show that the unusual ‘reversed binding mode’ observed in the crystal is triggered by changes in the protonation of binding groups at low pH. This research has important implications for fragment-based approaches to drug design, namely that the crystallization conditions and the chemical modification of ligands can have unexpected effects on the binding modes

  16. Vasoactive intestinal peptide binding sites and fibers in the brain of the pigeon Columba livia: An autoradiographic and immunohistochemical study

    International Nuclear Information System (INIS)

    Hof, P.R.; Dietl, M.M.; Charnay, Y.; Martin, J.L.; Bouras, C.; Palacios, J.M.; Magistretti, P.J.

    1991-01-01

    The distribution of vasoactive intestinal peptide (VIP) binding sites in the pigeon brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of VIP, which maintains the biological activity of the native peptide, was used throughout this study. The highest densities of binding sites were observed in the hyperstriatum dorsale, archistriatum, auditory field L of neostriatum, area corticoidea dorsolateralis and temporo-parieto-occipitalis, area parahippocampalis, tectum opticum, nucleus dorsomedialis anterior thalami, and in the periventricular area of the hypothalamus. Lower densities of specific binding occurred in the neostriatum, hyperstriatum ventrale and nucleus septi lateralis, dorsolateral area of the thalamus, and lateral and posteromedial hypothalamus. Very low to background levels of VIP binding were detected in the ectostriatum, paleostriatum primitivum, paleostriatum augmentatum, lobus parolfactorius, nucleus accumbens, most of the brainstem, and the cerebellum. The distribution of VIP-containing fibers and terminals was examined by indirect immunofluorescence using a polyclonal antibody against porcine VIP. Fibers and terminals were observed in the area corticoidea dorsolateralis, area parahippocampalis, hippocampus, hyperstriatum accessorium, hyperstriatum dorsale, archistriatum, tuberculum olfactorium, nuclei dorsolateralis and dorsomedialis of the thalamus, and throughout the hypothalamus and the median eminence. Long projecting fibers were visualized in the tractus septohippocampalis. In the brainstem VIP immunoreactive fibers and terminals were observed mainly in the substantia grisea centralis, fasciculus longitudinalis medialis, lemniscus lateralis, and in the area surrounding the nuclei of the 7th, 9th, and 10th cranial nerves

  17. Structural Changes of Zn(IIbleomycin Complexes When Bound to DNA Hairpins Containing the 5′-GT-3′ and 5′-GC-3′ Binding Sites, Studied through NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Shelby E. Follett

    2017-12-01

    Full Text Available We have previously investigated the diverse levels of disruption caused by Zn(IIBLMs with different C-termini to DNA hairpins containing 5′-GC-3′ and 5′-GT-3′ binding sites. The results of this investigation indicated that both the DNA-binding site and the bleomycin C-termini have an impact on the final conformation of the aforementioned hairpins in the drug-target complexes, as suggested by the different sets of intramolecular NOEs displayed by both oligonucleotides when bound to each Zn(IIBLM. The NMR signals elicited by 1H nuclei in the oligonucleotide bases and sugar moieties were also affected differently (shifted upfield or downfield in various patterns depending on the BLM C-termini and the binding site in the oligonucleotides. The overall conclusion derived from the precedent research is that the spatial conformation of target DNA segments in DNA-Zn(IIBLM complexes could be forged by interactions between drug and DNA that are guided by the DNA binding site and the BLM C-termini. The present study focuses on the structural alterations exhibited by Zn(IIbleomycin-A2, -B2, -A5 and Zn(IIpeplomycin molecules upon binding to the previously studied hairpins. Our main goal is to determine if different spatial conformations of the drugs in their DNA-bound forms are found in drug-DNA complexes that differ in the oligonucleotide binding site and BLM C-termini. Evidence that suggest that each Zn(IIbleomycin is structurally affected depending these two factors, as indicated by different sets of intramolecular NOE connectivities between drug protons and diverse patterns of shifting of their 1H-NMR signals, is provided.

  18. Biophysical characterization and functional studies on calbindin-D28K: A vitamin D-induced calcium-binding protein

    International Nuclear Information System (INIS)

    Leathers, V.L.

    1989-01-01

    Vitamin D dependent calcium binding protein, or calbindin-D, is the principal protein induced in the intestine in response to the steroid hormone 1,25(OH) 2 -vitamin D 3 . A definitive role for calbindin-D in vitamin D 3 mediated biological responses remains unclear. Biophysical and functional studies on chick intestinal calbindin-D 28K (CaBP) were initiated so that some insight might be gained into its relevance to the process of intestinal calcium transport. Calbindin-D belongs to a class of high affinity calcium binding proteins which includes calmodulin, parvalbumin and troponin C. The Ca 2+ binding stoichiometry and binding constants for calbindin-D 28K were quantitated by Quin 2 titration analysis. The protein was found to bind 5-6 Ca 2+ ions with a K D on the order of 10 -8 , in agreement with the 6 domains identified from the amino acid sequence. A slow Ca 2+ exchange rate (80 s -1 ) as assessed by 43 Ca NMR and extensive calcium dependent conformational changes in 1 H NMR spectra were also observed. Functional studies on chick intestinal CaBP were carried out by two different methods. Interactions between CaBP and intestinal cellular components were assessed via photoaffinity labeling techniques. Specific calcium dependent complexes for CaBP were identified with bovine intestinal alkaline phosphatase and brush border membrane proteins of 60 and 150 kD. CaBP was also found to co-migrate with the alkaline phosphatase activity of chick intestinal brush border membranes as evaluated by gel filtration chromatography. The second procedure for evaluating CaBP functionality has involved the quantitation of CaBP association with vesicular transport components as assessed by ELISA. CaBP, immunoreactivity was observed in purified lysosomes, microsomes and microtubules

  19. Responses to A(H1N1)pdm09 influenza vaccines in participants previously vaccinated with seasonal influenza vaccine: a randomized, observer-blind, controlled study.

    Science.gov (United States)

    Roy-Ghanta, Sumita; Van der Most, Robbert; Li, Ping; Vaughn, David W

    2014-11-01

    Prior receipt of a trivalent seasonal influenza vaccine (TIV) can affect hemagglutination inhibition (HI) antibody responses to pandemic influenza vaccines. We investigated the effect of TIV priming on humoral responses to AS03-adjuvanted and nonadjuvanted A(H1N1)pdm09 vaccines, the role of AS03 on cell-mediated immune (CMI) responses, and vaccine safety. Healthy adults (aged 19-40 years) were randomized 1:1:1:1 to receive TIV or saline followed 4 months later by 2 doses, 3 weeks apart, of adjuvanted or nonadjuvanted A(H1N1)pdm09 vaccine and followed up to study end (day 507). Pre- and postvaccination responses of HI and neutralizing antibody, CD4(+)/CD8(+) T cells, memory B cells, and plasmablasts were assessed. Ninety-nine of the 133 participants enrolled completed the study. No vaccine-related serious adverse events were recorded. In TIV-primed participants, A(H1N1)pdm09-specific antibody and CD4(+) T-cell and memory B-cell responses to the pandemic vaccine tended to be diminished. Vaccine adjuvantation led to increased responses of vaccine-homologous and -heterologous HI and neutralizing antibodies and CD4(+) T cells, homologous memory B cells, and plasmablasts. In healthy adults, prior TIV administration decreased humoral and CMI responses to A(H1N1)pdm09 vaccine. Adjuvantation of A(H1N1)pdm09 antigen helped to overcome immune interference between the influenza vaccines. No safety concerns were observed. Clinical Trials.gov identifier NCT00707967. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

  20. Responses to A(H1N1)pdm09 Influenza Vaccines in Participants Previously Vaccinated With Seasonal Influenza Vaccine: A Randomized, Observer-Blind, Controlled Study

    Science.gov (United States)

    Roy-Ghanta, Sumita; Van der Most, Robbert; Li, Ping; Vaughn, David W.

    2014-01-01

    Background. Prior receipt of a trivalent seasonal influenza vaccine (TIV) can affect hemagglutination inhibition (HI) antibody responses to pandemic influenza vaccines. We investigated the effect of TIV priming on humoral responses to AS03-adjuvanted and nonadjuvanted A(H1N1)pdm09 vaccines, the role of AS03 on cell-mediated immune (CMI) responses, and vaccine safety. Methods. Healthy adults (aged 19–40 years) were randomized 1:1:1:1 to receive TIV or saline followed 4 months later by 2 doses, 3 weeks apart, of adjuvanted or nonadjuvanted A(H1N1)pdm09 vaccine and followed up to study end (day 507). Pre- and postvaccination responses of HI and neutralizing antibody, CD4+/CD8+ T cells, memory B cells, and plasmablasts were assessed. Results. Ninety-nine of the 133 participants enrolled completed the study. No vaccine-related serious adverse events were recorded. In TIV-primed participants, A(H1N1)pdm09-specific antibody and CD4+ T-cell and memory B-cell responses to the pandemic vaccine tended to be diminished. Vaccine adjuvantation led to increased responses of vaccine-homologous and -heterologous HI and neutralizing antibodies and CD4+ T cells, homologous memory B cells, and plasmablasts. Conclusions. In healthy adults, prior TIV administration decreased humoral and CMI responses to A(H1N1)pdm09 vaccine. Adjuvantation of A(H1N1)pdm09 antigen helped to overcome immune interference between the influenza vaccines. No safety concerns were observed. Registration. Clinical Trials.gov identifier NCT00707967. PMID:24864125

  1. Molecular modelling studies of substrate binding to the lipase from Rhizomucor miehei

    Science.gov (United States)

    Yagnik, Asutosh T.; Littlechild, Jennifer A.; Turner, Nicholas J.

    1997-05-01

    Lipase enzymes have found increasingly widespread use, especially in biotransformation reactions in organic synthesis. Due to their efficiency and high enantioselectivity, they can be employed in a variety of reactions to carry out asymmetric hydrolyses, esterifications and transesterifications. However, the reasons for their stereospecificity have not been fully correlated with the enzyme structure. Employing molecular modelling techniques and existing experimental data, a transesterification reaction using Rhizomucor miehei lipase was studied. The results indicate that the major controlling factor for this reaction is hydrophobic in nature, providing support for previous literature hypotheses. In addition, computational experiments suggest that the origin of enantioselectivity is the formation of essential hydrogen bonds in and around the catalytic triad of active site residues. Only one enantiomer of the substrate is able to form these hydrogen bonds during the formation of the first tetrahedral transition state.

  2. [Coming-out, support from family of origin and relationship adjustment of lesbian mothers whose children were born in a previous heterosexual relationship: an exploratory study].

    Science.gov (United States)

    Vyncke, Johanna D; Julien, Danielle

    2005-01-01

    Lesbian couples differ from heterosexual couples in that they must develop their relationship within an environment that is generally unsympathetic to homosexuality, a fact that could accentuate the importance of family support. Furthermore, the disclosure of their sexual orientation by lesbian couples could also affect the support given by family members. The present study examines the effect of coming-out and family support on the relationship adjustment of lesbian mothers whose children were born within a heterosexual context. It was expected that family support would mediate the relationship between coming-out and relationship adjustment. Fifty-five lesbian mothers currently in a relationship answered questions about their perception of family support, on their coming-out behaviour and their relationship adjustment. Results revealed a positive relationship between coming-out and family support, and between family support and relationship adjustment, however no association was found between coming-out and relationship adjustment. The mediation model was therefore not confirmed. Finally, the authors discuss the implications of these results.

  3. Resonance energy transfer study on the proximity relationship between the GTP binding site and the rifampicin binding site of Escherichia coli RNA polymerase

    International Nuclear Information System (INIS)

    Kumar, K.P.; Chatterji, D.

    1990-01-01

    Terbium(III) upon complexation with guanosine 5'-triphosphate showed remarkable enhancement of fluorescence emission at 488 and 545 nm when excited at 295 nm. Analysis of the binding data yielded a value for the mean K d between Tb(III) and GTP of 0.2 μM, with three binding sites for TB(III) on GTP. 31 P and 1 H NMR measurements revealed that Tb(III) mainly binds the phosphate moiety of GTP. Fluorescence titration of the emission signals of the TbGTP complex with varying concentrations of Escherichia coli RNA polymerase resulted in a K d values of 4 μM between the TbGTP and the enzyme. It was observed that TbGTP can be incorporated in the place of GTP during E. coli RNA polymerase catalyzed abortive synthesis of dinucleotide tetraphosphate at T7A2 promoter. Both the substrate TbGTP and the inhibitor of the initiation of transcription rifampicin bind to the β-subunit of E. coli RNA polymerase. This allows the measurement of the fluorescence excited-state energy transfer from the donor TbGTP-RNA polymerase to the acceptor rifampicin. Both emission bands of Tb(III) overlap with the rifampicin absorption, and the distances at 50% efficiency of energy transfer were calculated to be 28 and 24 angstrom for the 488- and 545-nm emission bands, respectively. The distance between the substrate binding site and the rifampicin binding site on the β-subunit of E. coli RNA polymerase was measured to be around 30 angstrom. This suggest that the nature of inhibition of transcription by rifampicin is essentially noncompetitive with the substrate

  4. Ethanol intake and 3H-serotonin uptake II: A study in alcoholic patients using platelets 3H-paroxetine binding

    International Nuclear Information System (INIS)

    Daoust, M.; Boucly, P.; Ernouf, D.; Breton, P.; Lhuintre, J.P.

    1991-01-01

    The kinetic parameters of 3 H-paroxetine binding and 3 H-serotonin uptake were studied in platelets of alcoholic patients. There was no difference between alcoholic and non alcoholic subjects in 3 H-paroxetine binding. When binding and 3 H-serotonin uptake were studied, in the same plasma of the same subjects, the Vmax of serotonin uptake was increased in alcoholics. The data confirm the involvement of serotonin uptake system in alcohol dependance and suggest that serotonin uptake and paroxetine binding sites may be regulated independently in this pathology

  5. Spectroscopic profiling and computational study of the binding of tschimgine: A natural monoterpene derivative, with calf thymus DNA

    Science.gov (United States)

    Khajeh, Masoumeh Ashrafi; Dehghan, Gholamreza; Dastmalchi, Siavoush; Shaghaghi, Masoomeh; Iranshahi, Mehrdad

    2018-03-01

    DNA is a major target for a number of anticancer substances. Interaction studies between small molecules and DNA are essential for rational drug designing to influence main biological processes and also introducing new probes for the assay of DNA. Tschimgine (TMG) is a monoterpene derivative with anticancer properties. In the present study we tried to elucidate the interaction of TMG with calf thymus DNA (CT-DNA) using different spectroscopic methods. UV-visible absorption spectrophotometry, fluorescence and circular dichroism (CD) spectroscopies as well as molecular docking study revealed formation of complex between TMG and CT-DNA. Binding constant (Kb) between TMG and DNA was 2.27 × 104 M- 1, that is comparable to groove binding agents. The fluorescence spectroscopic data revealed that the quenching mechanism of fluorescence of TMG by CT-DNA is static quenching. Thermodynamic parameters (ΔH analysis, viscosity measurements and molecular docking.

  6. RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study

    International Nuclear Information System (INIS)

    Weber, Damien C; Miralbell, Raymond; Wang, Hui; Cozzi, Luca; Dipasquale, Giovanna; Khan, Haleem G; Ratib, Osman; Rouzaud, Michel; Vees, Hansjoerg; Zaidi, Habib

    2009-01-01

    A study was performed comparing volumetric modulated arcs (RA) and intensity modulation (with photons, IMRT, or protons, IMPT) radiation therapy (RT) for patients with recurrent prostate cancer after RT. Plans for RA, IMRT and IMPT were optimized for 7 patients. Prescribed dose was 56 Gy in 14 fractions. The recurrent gross tumor volume (GTV) was defined on 18 F-fluorocholine PET/CT scans. Plans aimed to cover at least 95% of the planning target volume with a dose > 50.4 Gy. A maximum dose (D Max ) of 61.6 Gy was allowed to 5% of the GTV. For the urethra, D Max was constrained to 37 Gy. Rectal D Median was < 17 Gy. Results were analyzed using Dose-Volume Histogram and conformity index (CI 90 ) parameters. Tumor coverage (GTV and PTV) was improved with RA (V 95% 92.6 ± 7.9 and 83.7 ± 3.3%), when compared to IMRT (V 95% 88.6 ± 10.8 and 77.2 ± 2.2%). The corresponding values for IMPT were intermediate for the GTV (V 95% 88.9 ± 10.5%) and better for the PTV (V 95% 85.6 ± 5.0%). The percentages of rectal and urethral volumes receiving intermediate doses (35 Gy) were significantly decreased with RA (5.1 ± 3.0 and 38.0 ± 25.3%) and IMPT (3.9 ± 2.7 and 25.1 ± 21.1%), when compared to IMRT (9.8 ± 5.3 and 60.7 ± 41.7%). CI 90 was 1.3 ± 0.1 for photons and 1.6 ± 0.2 for protons. Integral Dose was 1.1 ± 0.5 Gy*cm 3 *10 5 for IMPT and about a factor three higher for all photon's techniques. RA and IMPT showed improvements in conformal avoidance relative to fixed beam IMRT for 7 patients with recurrent prostate cancer. IMPT showed further sparing of organs at risk

  7. Calf thymus DNA-binding ability study of anthocyanins from purple sweet potatoes ( Ipomoea batatas L.).

    Science.gov (United States)

    Wang, Dan; Wang, Xirui; Zhang, Chao; Ma, Yue; Zhao, Xiaoyan

    2011-07-13

    A total of 10 anthocyanin compounds were identified from five purple sweet potato ( Ipomoea batatas L.) varieties, Qunzi, Zishu038, Ji18, Jingshu6, and Ziluolan, by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to assess their calf thymus DNA-binding ability in vitro. The interaction between anthocyanins and calf thymus DNA in Tris-HCl buffer solution (pH 6.9) was evaluated by fluorescence spectroscopy. Using ethidium bromide (EB) as a fluorescence probe, fluorescence quenching of the emission peak was seen in the DNA-EB system when anthocyanins were added, indicating that the anthocyanins bound with DNA. The acylated groups influenced the ability of the interaction with DNA. Anthocyanins from purple sweet potato with more acylated groups in sorphorose have a stronger binding ability with DNA.

  8. Binding of caffeine, theophylline, and theobromine with human serum albumin: A spectroscopic study

    Science.gov (United States)

    Zhang, Hong-Mei; Chen, Ting-Ting; Zhou, Qiu-Hua; Wang, Yan-Qing

    2009-12-01

    The interaction between three purine alkaloids (caffeine, theophylline, and theobromine) and human serum albumin (HSA) was investigated using UV/vis absorption, circular dichroism (CD), fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques. The results revealed that three alkaloids caused the fluorescence quenching of HSA by the formation of alkaloid-HSA complex. The binding site number n and apparent binding constant KA, corresponding thermodynamic parameters the free energy change (Δ G), enthalpy change (Δ H), and entropy change (Δ S) at different temperatures were calculated. The hydrophobic interaction plays a major role in stabilizing the complex. The distance r between donor (HSA) and acceptor (alkaloids) was obtained according to fluorescence resonance energy transfer. The effect of alkaloids on the conformation of HSA was analyzed using circular dichroism (CD), UV/vis absorption, synchronous fluorescence and three-dimensional fluorescence spectra techniques.

  9. The binding of cytochrome c to neuroglobin: A docking and surface plasmon resonance study

    DEFF Research Database (Denmark)

    Bønding, Signe Helbo; Henty, K.; Dingley, A.J.

    2008-01-01

    is associated with a small unfavourable enthalpy change (1.9 kcal mol-1) and a moderately large, favourable entropy change (14.8 cal mol-1 deg-1). The sensitivity of the binding constant to the presence of salt suggests that the complex formation involves electrostatic interactions.......It has recently been proposed that the role of neuroglobin in the protection of neurons from ischaemia induced cell death requires the formation of a transient complex with cytochrome c. No such complex has yet been isolated. Here, we present the results of soft docking calculations, which indicate...... one major binding site for cytochrome c to neuroglobin. The results yield a plausible structure for the most likely complex structure in which the hemes of each protein are in close contact. NMR analysis identifies the formation of a weak complex in which the heme group of cytochrome c is involved...

  10. Toward understanding macrocycle specificity of iron on the dioxygen-binding ability: a theoretical study.

    Science.gov (United States)

    Sun, Yong; Chen, Kexian; Jia, Lu; Li, Haoran

    2011-08-14

    In an effort to examine the interaction between dioxygen and iron-macrocyclic complexes, and to understand how this interaction was affected by those different macrocyclic ligands, dioxygen binding with iron-porphyrin, iron-phthalocyanine, iron-dibenzotetraaza[14]annulene, and iron-salen complexes is investigated by means of quantum chemical calculations utilizing Density Functional Theory (DFT). Based on the analysis of factors influencing the corresponding dioxygen binding process, it showed that different macrocyclic ligands possess different O-O bond distances, and different electronic configurations for the bound O(2) and non-aromatic macrocyclic ligands favor dioxygen activation. Furthermore, the smaller the energy gap between the HOMO of iron-macrocyclic complexes and the LUMO of dioxygen, the more active the bound O(2) becomes, with a longer O-O bond distance and a shorter Fe-O bond length.

  11. A coupled channel study on a binding mechanism of positronic alkali atoms

    International Nuclear Information System (INIS)

    Kubota, Yoshihiro; Kino, Yasushi

    2008-01-01

    In order to investigate the binding mechanism of weakly bound states of positronic alkali atoms, we calculate the energies and wavefunctions using the Gaussian expansion method (GEM) where a positronium (Ps)-alkali ion channel and a positron-alkali atom channel are explicitly introduced. The energies of the bound states are updated using a model potential that reproduces well the observed energy levels of alkali atoms. The binding mechanism of the positronic alkali atom is analyzed by the wavefunctions obtained. The structure of the positronic alkali atom has been regarded as a Ps cluster orbiting the alkali ion, which is described by the Ps-alkali ion channel. We point out that the fraction having the positron-alkali atom configuration is small but plays an indispensable role for the weakly bound system

  12. Electron microscopic and physico-chemical studies of DNA complexes with synthetic oligopeptides: binding specificity and DNA compact structures.

    Science.gov (United States)

    Vengerov, Y Y; Semenov, T E; Surovaya, A N; Sidorova NYu; Streltsov, S A; Khorlin, A A; Zhuze, A L; Gursky, G V

    1988-10-01

    Binding to DNA of two synthetic peptides, Val-Thr-Thr-Val-Val-NH-NH-Dns and Thr-Val-Thr-Lys-Val-Gly-Thr-Lsy-Val-Gly-Thr-Val-Val-NH-NH-Dns (where Dns is a residue of 5-dimethylaminonaphthalene-1-sulfonic acid), has been studied by circular dichroism, electron microscopy and fluorescence methods. It has been found that these two peptides can self-associate in aqueous solution as follows from the fact that concentration-dependent changes are observed in the UV absorbance and fluorescence spectra. The two peptides can bind to DNA both in self-associated and monomeric forms. The pentapeptide in the beta-associated form binds more strongly to poly(dG).poly(dC) than to poly[d(A-C)].poly[d(G-T)] and poly(dA).poly(dT) whereas the tridecapeptide exhibits an opposite order of preferences binding more strongly to poly[d(A-C)].poly[d(G-T)] and poly(dA).poly(dT) than to poly(dG).poly(dC). Binding is a cooperative process which is accompanied by the DNA compaction at peptide/DNA base pair ratios greater than 1. At the initial stage of the compaction process, the coalescence of DNA segments covered by bound peptide molecules leads to the formation of DNA loops stabilized by the interaction between peptide molecules bound to different DNA segments. Further increase in the peptide/DNA ratio leads to the formation of rod-like structures each consisting of two or more double-stranded DNA segments. The final stage of the compaction process involves folding of fibrillar macromolecular complexes into a globular structure containing only one DNA molecule.

  13. High level theoretical study of binding and of the potential energy surface in benzene-hydride system

    Energy Technology Data Exchange (ETDEWEB)

    Coletti, Cecilia, E-mail: ccoletti@unich.it [Dipartimento di Scienze del Farmaco, Universita ' G. d' Annunzio' Chieti-Pescara, Via dei Vestini 31, 66100 Chieti (Italy); Re, Nazzareno [Dipartimento di Scienze del Farmaco, Universita ' G. d' Annunzio' Chieti-Pescara, Via dei Vestini 31, 66100 Chieti (Italy)

    2012-04-04

    Graphical abstract: In-plane minimum geometries for benzene-H{sup -} non-covalent adducts: linear adduct (left) with the hydride ion hydrogen bonded to one aromatic hydrogen; bifurcated adduct (right), with the hydride ion hydrogen bonded to two adjacent aromatic hydrogens. Highlights: Black-Right-Pointing-Pointer Theoretical study on covalent and non-covalent binding in benzene-hydride. Black-Right-Pointing-Pointer Two non-covalent stable adducts were characterized in the in-plane geometry. Black-Right-Pointing-Pointer Significant sections of the potential energy surface were determined. Black-Right-Pointing-Pointer Formation of a very stable C{sub 6}H{sub 7}{sup -} anion upon covalent binding to carbon. - Abstract: High level ab initio calculations were performed on the interaction of the hydride anion with benzene, a system of potential interest for modelling the interactions occurring in hydrogen rich planetary atmospheres. We investigated both non-covalent and covalent binding, exploring the complete basis set limit using highly correlated MP2 and CCSD(T) levels of theory. Two non-covalent minima on the potential energy surface have been characterized, and found to correspond to moderately strong hydrogen bonding interactions. To gain further insight on the nature of binding, the total interaction energy was decomposed into its physically meaningful components and selected sections of the potential energy surface were calculated. Moreover, we found that H{sup -} can easily covalently bind to one of the carbon atoms of benzene to form a stable C{sub 6}H{sub 7}{sup -} anion, a global minimum on the potential energy surface, characterized by a puckered geometry, with a carbon atom bending out of the benzene plane. A slightly less stable planar C{sub 6}H{sub 7}{sup -} structure was also identified, corresponding to the transition state for the flipping motion of the puckered species.

  14. Spectroscopic investigations of the B12-binding subunit of glutamate mutase: refined solution structure of the complex with the B12-nucleotide, dynamics and binding studies with two corrinoid cofactors

    International Nuclear Information System (INIS)

    Eichmueller, C.

    2002-06-01

    Glutamate mutase is an enzyme isolated from Clostridium tetanomorphum and Clostridium cochlearum. It catalyses the reversible rearrangement of (2S)-glutamate to (2S,3S)-3-methylaspartate. Coenzyme B12 is required as cofactor for an active enzyme, as the first step of the catalytic cycle is the homolytic cleavage of the cobalt-carbon bond. The rearrangement itself follows a radical mechanism. The holoenzyme is an alpha2beta2 heterotetramer containing two identical catalytic and two B12 binding domains, as well as two coenzyme B12 molecules. The smaller B12 binding domain from Clostridium tetanomorphum, MutS, is known to bind coenzyme B12 in its unusual 'base-off' form. A conserved histidine residue coordinates to the cobalt atom instead of the normally coordinated dimethlybenzimidole in free coenzyme B12. In the present work a refined solution structure of the B12 binding subunit from Clostridium tetanomorphum (MutS) in complex with the detached nucleotide loop of coenzyme B12 has been determined using nuclear magnetic resonance. The found topology is almost identical to the crystal structure of glutamate mutase from C.cochlearum [Reitzer et al., 1999], in contrast to the solution structures obtained for apo-MutS [Hoffmann et al., 2001; Tollinger et al., 1998] and apo-GlmS [Hoffmann et al., 1999]. In these two structures a helix at one side of the B12 nucleotide loop binding pocket is mostly unstructured and shows motions on a microsecond to millisecond timescale. The previously found stabilization of this helix upon B12-nucleotide binding [Tollinger et al., 2001] was confirmed using 13C and 15N labeled MutS. Some differences are found in the structure of the binding pocket and the bound nucleotide loop compared to the crystal structure. This indicates that additional conformational changes occur upon binding of the corrin ring of coenzyme B12. NMR-relaxation measurements performed on apo-MutS showed interesting slow molecular motions not only in the mainly

  15. Spectroscopic study of drug-binding characteristics of unmodified and pNPA-based acetylated human serum albumin: Does esterase activity affect microenvironment of drug binding sites on the protein?

    International Nuclear Information System (INIS)

    Moradi, Nastaran; Ashrafi-Kooshk, Mohammad Reza; Ghobadi, Sirous; Shahlaei, Mohsen; Khodarahmi, Reza

    2015-01-01

    Human serum albumin (HSA) is the most prominent extracellular protein in blood plasma. There are several binding sites on the protein which provide accommodation for structurally-unrelated endogenous and exogenous ligands and a wide variety of drugs. “Esterase-like” activity (hydrolysis of p-nitrophenyl esters) by the protein has been also reported. In the current study, we set out to investigate the interaction of indomethacin and ibuprofen with the unmodified and modified HSA (pNPA-modified HSA) using various spectroscopic techniques. Fluorescence data showed that 1:1 binding of drug to HSA is associated with quenching of the protein intrinsic fluorescence. Decrease of protein surface hydrophobicity (PSH), alteration in drug binding affinity and change of the protein stability, after esterase-like activity and permanent acetylation of HSA, were also documented. Analysis of the quenching and thermodynamic parameters indicated that forces involved in drug–HSA interactions change upon the protein modification. - Highlights: • Binding propensity of indomethacin extremely decreased upon the protein acetylation. • There is no ibuprofen binding after protein acetylation. • Protein stability changes upon drug binding as well as protein acetylation. • Drug pharmacokinetics may be influenced under co-administration of HSA-modifier drugs

  16. Spectroscopic study of drug-binding characteristics of unmodified and pNPA-based acetylated human serum albumin: Does esterase activity affect microenvironment of drug binding sites on the protein?

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Nastaran [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Faculty of Pharmaceutical Sciences, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Ashrafi-Kooshk, Mohammad Reza [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Ghobadi, Sirous [Department of Biology, Faculty of Sciences, Razi University, Kermanshah (Iran, Islamic Republic of); Shahlaei, Mohsen [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Faculty of Pharmaceutical Sciences, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Khodarahmi, Reza, E-mail: rkhodarahmi@mbrc.ac.ir [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Faculty of Pharmaceutical Sciences, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

    2015-04-15

    Human serum albumin (HSA) is the most prominent extracellular protein in blood plasma. There are several binding sites on the protein which provide accommodation for structurally-unrelated endogenous and exogenous ligands and a wide variety of drugs. “Esterase-like” activity (hydrolysis of p-nitrophenyl esters) by the protein has been also reported. In the current study, we set out to investigate the interaction of indomethacin and ibuprofen with the unmodified and modified HSA (pNPA-modified HSA) using various spectroscopic techniques. Fluorescence data showed that 1:1 binding of drug to HSA is associated with quenching of the protein intrinsic fluorescence. Decrease of protein surface hydrophobicity (PSH), alteration in drug binding affinity and change of the protein stability, after esterase-like activity and permanent acetylation of HSA, were also documented. Analysis of the quenching and thermodynamic parameters indicated that forces involved in drug–HSA interactions change upon the protein modification. - Highlights: • Binding propensity of indomethacin extremely decreased upon the protein acetylation. • There is no ibuprofen binding after protein acetylation. • Protein stability changes upon drug binding as well as protein acetylation. • Drug pharmacokinetics may be influenced under co-administration of HSA-modifier drugs.

  17. Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain

    DEFF Research Database (Denmark)

    Smith, Donald F; Dyve, Suzan; Minuzzi, Luciano

    2006-01-01

    Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain......Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain...

  18. Review of previous geophysical and geological studies

    Digital Repository Service at National Institute of Oceanography (India)

    Levchenko, O.V.; Neprochnov, Y.P.; Rao, D.G.; Subrahmanyam, C.; Murthy, K.S.R.

    stream_size 5 stream_content_type text/plain stream_name Mem_Geol_Soc_India_39_5.pdf.txt stream_source_info Mem_Geol_Soc_India_39_5.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  19. Synthesis, antimalarial activity, heme binding and docking studies of N-substituted 4-aminoquinoline-pyrimidine molecular hybrids.

    Science.gov (United States)

    Maurya, Shiv Shyam; Khan, Shabana I; Bahuguna, Aparna; Kumar, Deepak; Rawat, Diwan S

    2017-03-31

    A series of novel N-substituted 4-aminoquinoline-pyrimidine hybrids have been synthesized via simple and economic route and evaluated for their antimalarial activity. Most compounds showed potent antimalarial activity against both CQ-sensitive and CQ-resistant strains with high selectivity index. All the compounds were found to be non-toxic to the mammalian cell lines. The most active compound 7b was analysed for heme binding activity using UV-spectrophotometer. Compound was found to interact with heme and a complex formation between compound and heme in a 1:1 stoichiometry ratio was determined using job plots. The interaction of these hybrids was also investigated by the molecular docking studies in the binding site of wild type Pf-DHFR-TS and quadruple mutant Pf-DHFR-TS. The pharmacokinetic property analysis of best active compounds was also studied by ADMET prediction. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Experimental strategies for studying G protein-coupled receptor homo- and heteromerization with radioligand binding and signal transduction methods.

    Science.gov (United States)

    Maggio, Roberto; Rocchi, Cristina; Scarselli, Marco

    2013-01-01

    Before the molecular biology era, functional experiments on isolated organs and radioligand binding and biochemical experiments on animal tissues were widely used to characterize G protein-coupled receptors (GPCRs). The introduction of recombinant cell lines expressing a single GPCR type has been a big step forward for studying both drug-receptor interactions and signal transduction. Before the introduction of the concept of receptor oligomerization, all data generated were attributed to the interaction of drugs with receptor monomers. Now, considerable data must be reinterpreted in light of receptor homo- and heteromerization. In this chapter, we will review some of the methods used to study radioligand binding and signal transduction modifications induced by GPCR homo- and heteromerization. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Study on insulin receptor binding characteristics of insulin-IUdR

    International Nuclear Information System (INIS)

    Ou Xiaohong; Kuang Anren; Liang Zhenglu; Peng Xian; Zhong Yuguo

    2002-01-01

    Objective: It has been reported that several kinds of tumors express increased insulin receptors and the molecule of insulin can be internalized in cells and enter the nuclei through the mediation of the insulin receptor. The authors investigated the receptor binding characteristics of insulin-IUdR for the possibility of using insulin as carriers for carcinoma targeted therapy by receptor mediation. Methods: IUdR (idoxuridine) was covalently linked to insulin using the bifunctional reagent succinic acid. The insulin-IUdR conjugate was purified by polyacrylamide agarose gel electrophoresis. The human hepatocellular carcinoma specimens confirmed histologically were obtained from patients at surgery and immediately frozen under -80 degree C. Cell membrane fractions were isolated by sucrose density gradient centrifugation. Competitive displacement of 125 I-insulin with insulin and insulin-IUdR binding to the insulin receptor were carried out. Values of IC 50 and KI were calculated to observe the characteristics of insulin-IUdR binding to the insulin receptor. Results: Insulin-IUdR competed as effectively as insulin with 125 I-insulin for binding to insulin receptors. The values of IC 50 1 and IC 50 2 for insulin-IUdR were (11.50 +- 2.83) nmol/L and (19.35 +- 5.11) nmol/L, respectively; the values of KI1 and KI2 for insulin-IUdR were (11.26 +- 2.65) nmol/L and (19.30 +- 5.02) nmol/L, respectively, while values of IC 50 1 and IC 50 2 for insulin were (5.01 +- 1.24) nmol/L and (17.75 +- 4.86) nmol/L, respectively. The values of KI1 and KI2 for insulin were (4.85 +- 1.12) nmol/L and (17.69 +- 4.81) nmol/L, respectively. Conclusions: Insulin-IUdR could bind with the insulin receptor with high affinity. The result shows that there is a possibility of using insulin as carriers for carcinoma targeted therapy through receptor mediation

  2. Interaction between Plectranthus barbatus herbal tea components and acetylcholinesterase: binding and activity studies.

    Science.gov (United States)

    Falé, Pedro L V; Ascensão, Lia; Serralheiro, M Luisa; Haris, Parvez I

    2012-11-01

    Plectranthus barbatus water extracts, have been used as herbal teas, for the treatment of various diseases. In a previous study it was demonstrated that antioxidant and anti-acetylcholinesterase active extract constituents and their metabolites were found in the plasma of rats after P. barbatus tea intraperitoneal administration. Consequently, a decrease in brain acetylcholinesterase activity occurred. The aim of the present research is to elucidate how P. barbatus extract components interact with acetylcholinesterase. The estimated thermodynamic parameters suggest that the main intermolecular interaction is hydrophobic association, although hydrogen bonds between flavonoids and the active gorge of the acetylcholinesterase molecule seem to occur and have a great impact on acetylcholinesterase inhibition. The hydroxyl positions in flavonoids seem to be of utmost importance for enzyme inhibition, as they interact with specific amino acid residues in the active gorge. FTIR analysis showed that the plant extract components do not interfere with the secondary structure of the enzyme, but decreases the rate of hydrogen-deuterium exchange, possibly by decreasing solvent accessibility in the acetylcholinesterase active gorge. The spectroscopic data complements docking studies of acetylcholinesterase inhibition by plant phenolic compounds, clarifying the dominant interactions between enzyme and inhibitor and the most important structural features of the inhibitor molecules.

  3. Accumulation of explosives in hair--Part 3: Binding site study.

    Science.gov (United States)

    Oxley, Jimmie C; Smith, James L; Kirschenbaum, Louis J; Marimiganti, Suvarna; Efremenko, Irena; Zach, Raya; Zeiri, Yehuda

    2012-05-01

    This study extends previous work on the sorption of explosives to the hair matrix. Specifically, we have studied the interaction of 2,4,6-trinitrotoluene (TNT) and triacetone triperoxide (TATP) as a function of chemical pretreatment with acetonitrile, neutral and alkaline hydrogen peroxide, methanolic KOH and potassium permanganate, and the morphological changes that accompany these treatments. While differences in vapor pressure can account for quantitative differences between TNT and TATP sorption, both are markedly affected by the chemical rinses. Examination of the hair surface shows different degrees of smoothening following rinsing, suggesting that the attachment to hair is largely a surface phenomenon involving the 18-methyleicosanoic acid lipid layer. Density functional theory calculations were employed to explore possible nucleation sites of TATP microcrystals on the hair. We conclude that some of the sites on melanin granular surfaces may support nucleation of TATP microcrystals. Moreover, the calculations support the experimental finding that dark hair adsorbs explosives better than light hair. © 2012 American Academy of Forensic Sciences.

  4. Synthesis, biological investigation, calf thymus DNA binding and docking studies of the sulfonyl hydrazides and their derivatives

    Science.gov (United States)

    Murtaza, Shahzad; Shamim, Saima; Kousar, Naghmana; Tahir, Muhammad Nawaz; Sirajuddin, Muhammad; Rana, Usman Ali

    2016-03-01

    The present study describes the syntheses and biological investigations of sulfonyl hydrazides and their novel derivatives. The detailed investigations involved the characterization of the newly synthesized compounds using FTIR, NMR, mass spectrometry and by single crystal X-Ray diffraction (XRD) analysis techniques. The binding tendencies of these compounds with CT-DNA (calf thymus DNA) have been explored by electronic absorption (UV) spectroscopy and viscosity measurement. The binding constant (K) and Gibb's free energy (ΔG) values were also calculated accordingly. In addition, we also investigated the biological activities such as antioxidant, antibacterial, enzyme inhibition and DNA interactions. The antioxidant activity was assayed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, while antibacterial activity was investigated against four bacterial strains (viz. Escherichia coli, Crynibacteria bovius, Staphylococcus auras and Bacillus antherasis) by employing the common disc diffusion method. Enzyme inhibition activity of the synthesized compounds was examined against butyrylcholinestrase. The results of enzyme inhibition activity and the DNA binding interaction studies were also collected through molecular docking program using computational analysis. Our study reveals that the newly synthesized compounds possess moderate to good biological activities.

  5. Spectrofluorometric and thermal gravimetric study on binding interaction of thiabendazole with hemoglobin on epoxy-functionalized magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Maltas, Esra, E-mail: maltasesra@gmail.com; Ozmen, Mustafa

    2015-09-01

    The interaction of thiabendazole (Tbz) with hemoglobin (Hb) on epoxy-functionalized iron oxide nanoparticles was presented in this study. The binding capacity of Tbz was determined by measuring at an excitation wavelength of 299 nm using fluorescence spectroscopy. The thermodynamic parameters of the Hb–Tbz interaction were calculated from Stern–Volmer and van't Hoff equations. The values of enthalpy change, ∆H, and entropy change, ∆S, were found to be 0.20 kJ mol{sup −1} and 0.70 J mol{sup −1} K{sup −1}, respectively, which indicates that the hydrophilic interaction plays a main role in the binding process. The interaction ability was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Also, the thermal behavior of the Hb–Tbz interaction on functionalized iron oxide nanoparticles was studied by using the thermogravimetric analysis (TGA) technique in the temperature range of 25–950 °C, and then the kinetic parameters for the thermal decomposition were determined using the Horowitz–Metzger method. - Highlights: • Hb was immobilized by covalent attachment on GPTS–SPIONs. • Interaction of Tbz with Hb–GPTS–SPIONs was studied. • Thermodynamic parameters for interaction were calculated. • Hydrophilic interaction plays a main role in the binding process.

  6. Impact of binding study advice on study behavior- and pre-university education qualification factors in a problem-based psychology bachelor

    NARCIS (Netherlands)

    de Koning, B.B.; Loyens, S.M.M; Smeets, G.; Rikers, R.M.J.P.; Van der Molen, H.T.

    2014-01-01

    In the Netherlands, university programs increasingly use the binding study advice (BSA) to select students after the first year. Students with insufficient progress after the first year and who therefore do not conform to pre-defined BSA norms have to quit their program. This study investigated

  7. Impact of Binding Study Advice on Study Behavior and Pre-University Education Qualification Factors in a Problem-Based Psychology Bachelor Program

    Science.gov (United States)

    de Koning, Björn B.; Loyens, Sofie M. M.; Rikers, Remy M. J. P.; Smeets, Guus; van der Molen, Henk T.

    2014-01-01

    In the Netherlands, university programs increasingly use the binding study advice (BSA) to select students after the first year. Students with insufficient progress after the first year and who therefore do not conform to pre-defined BSA norms have to quit their program. This study investigated whether the introduction of the BSA is associated…

  8. Structural and functional studies of Escherichia coli aggregative adherence fimbriae (AAF/V) reveal a deficiency in extracellular matrix binding.

    Science.gov (United States)

    Jønsson, Rie; Liu, Bing; Struve, Carsten; Yang, Yi; Jørgensen, René; Xu, Yingqi; Jenssen, Håvard; Krogfelt, Karen A; Matthews, Steve

    2017-03-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging cause of acute and persistent diarrhea worldwide. The pathogenesis of different EAEC stains is complicated, however, the early essential step begins with attachment of EAEC to intestinal mucosa via aggregative adherence fimbriae (AAFs). Currently, five different variants have been identified, which all share a degree of similarity in the gene organization of their operons and sequences. Here, we report the solution structure of Agg5A from the AAF/V variant. While preserving the major structural features shared by all AAF members, only Agg5A possesses an inserted helix at the beginning of the donor strand, which together with altered surface electrostatics, renders the protein unable to interact with fibronectin. Hence, here we characterize the first AAF variant with a binding mode that varies from previously described AAFs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Proton and metal ion binding to natural organic polyelectrolytes-I. Studies with synthetic model compounds

    Science.gov (United States)

    Marinsky, J.A.; Reddy, M.M.

    1984-01-01

    A unified physico-chemical model, based on a modified Henderson-Hasselbalch equation, for the analysis of ion complexation reactions involving charged polymeric systems is presented and verified. In this model pH = pKa+p(??Ka) + log(??/1 - ??) where Ka is the intrinsic acid dissociation constant of the ionizable functional groups on the polymer, ??Ka is the deviation of the intrinsic constant due to electrostatic interaction between the hydrogen ion and the polyanion, and alpha (??) is the polyacid degree of ionization. Using this approach pKa values for repeating acidic units of polyacrylic (PAA) and polymethacrylic (PMA) acids were found to be 4.25 ?? 0.03 and 4.8 ?? 0.1, respectively. The polyion electrostatic deviation term derived from the potentiometric titration data (i.e. p(??Ka)) is used to calculate metal ion concentration at the complexation site on the surface of the polyanion. Intrinsic cobalt-polycarboxylate binding constants (7.5 for PAA and 5.6 for PMA), obtained using this procedure, are consistent with the range of published binding constants for cobalt-monomer carboxylate complexes. In two phase systems incorporation of a Donnan membrane potential term allows determination of the intrinsic pKa of a cross-linked PMA gel, pKa = 4.83, in excellent agreement with the value obtained for the linear polyelectrolyte and the monomer. Similarly, the intrinsic stability constant for cobalt ion binding to a PMA-gel (??CoPMA+ = 11) was found to be in agreement with the linear polyelectrolyte analogue and the published data for cobalt-carboxylate monodentate complexes. ?? 1984.

  10. Fast kinetic studies on the allosteric interactions between acetylcholine receptor and local anesthetic binding sites.

    Science.gov (United States)

    Heidmann, T; Changeux, J P

    1979-02-15

    Preincubation of receptor-rich membrane fragments from Torpedo marmorata with tertiary amine local anesthetics and several toxins such as histrionicotoxin, crotoxin and cerulotoxin, modifies the amplitude and time course of the relaxation processes monitored upon rapid mixing of the membrane fragments with the fluorescent agonist, Dns-C6-Cho. In particular, the amplitude of the rapid relaxation process, which is proportional to the fraction of acetylcholine receptor sites in a high-affinity state, increases; accordingly, the rate constant of the 'slow' and 'intermediate' relaxation processes also increases up to ten times (except with histrionicotoxin) whereas in a higher range of local anesthetic concentrations the rate constant of the 'rapid' relaxation process decreases. The data are accounted for by a two-state model of the acetylcholine regulator, assuming distinct binding sites for cholinergic agonists and local anesthetics and allosteric interactions between these two classes of sites; local anesthetics stabilize the regulator in a high-affinity state for agonists even in the absence of agonist, and modify the rate constants for th interconversions between the low-affinity and high-affinity states. The model accounts for the 'slow' fluorescence increase monitored upon addition of local anesthetics to a suspension of receptor-rich membranes supplemented with trace amounts of Dns-C6-Cho. The effect of local anesthetics on the apparent rate constant of the 'rapid' relaxation process can be accounted for on the basis of an additional low-affinity binding of local anesthetics to the acetylcholine receptor site. Finally the increase of the apparent rate constant of the 'intermediate' relaxation process can be simply accounted for by assuming the existence of a third state, corresponding to the 'active' state, to which local anesthetics bind and block ionic transport.

  11. A population-based study of morbidity and mortality in mannose-binding lectin deficiency

    DEFF Research Database (Denmark)

    Dahl, Morten; Tybjaerg-Hansen, Anne; Schnohr, Peter

    2004-01-01

    Reduced levels of wild-type mannose-binding lectin (MBL) may increase susceptibility for infection, other common diseases, and death. We investigated associations between MBL deficiency and risk of infection, other common diseases, and death during 24, 24, and 8 yr of follow-up, respectively. We...... genotyped 9,245 individuals from the adult Danish population for three MBL deficiency alleles, B, C, and D, as opposed to the normal noncarrier A allele. Hospitalization incidence per 10,000 person. yr was 644 in noncarriers compared with 631 in heterozygotes (log-rank: P = 0.39) and 658 in deficiency...

  12. Differential scanning calorimetry study on the binding of nucleic acids to dimyristoylphosphatidylcholine-sphingosine liposomes.

    Science.gov (United States)

    Kõiv, A; Mustonen, P; Kinnunen, P K

    1994-03-31

    Binding of DNA and RNA to sphingosine-containing dimyristoylphosphatidylcholine (DMPC) liposomes was characterized by differential scanning calorimetry. The thermal phase behaviour of neat DMPC liposomes was unaffected by the presence of the nucleic acids. However, significant alterations in the melting profiles of the DMPC/sphingosine composite membranes were produced by DNA and RNA, thus revealing their binding to the liposomes. For example, for 79:21 (molar ratio) DMPC/sphingosine liposomes a single endotherm at 29.1 degrees C with an enthalpy of 6.3 kcal/mol lipid was observed. In the presence of DNA at the nucleotide/sphingosine ratio of 0.6 this endotherm separated into three distinct peaks at 28.0, 31.4 and 35.1 degrees C, together with an approximately 22% reduction in the total enthalpy. Further increase in DNA concentration up to 1.5 nucleotides per sphingosine led to complete loss of the original heat absorption peak of the DMPC/sphingosine liposomes, while an endotherm at 34.3 degrees C with delta H of 2.7 kcal/mol developed. By visual inspection, rapid and extensive aggregation of the liposomes due to DNA was evident. Evidence for DNA-induced phase separation was also provided by compression isotherms of sphingosine containing DMPC monolayers recorded over an aqueous buffer both in the presence and absence of DNA. The effects of RNA on the thermal phase behaviour of the composite liposomes were qualitatively similar to those described above for DNA. Notably, the presence of eggPA abolished the nucleic acid induced heat capacity changes for DMPC/sphingosine liposomes probably because of neutralization of the positive charge of sphingosine. The binding of DNA to DMPC/sphingosine liposomes occurred both below and above the lipid phase transition temperature, as shown by fluorescence resonance energy transfer utilizing adriamycin-labelled DNA as a quencher and membrane incorporated pyrene-labelled phospholipid as a donor. However, the apparent binding to

  13. Study of binding properties of lanthanum to wheat roots by INAA

    International Nuclear Information System (INIS)

    Zhang, Z.Y.; Li, F.L.; Xiao, H.Q.; Chai, Z.F.; Xu, L.; Liu, N.

    2004-01-01

    Chemical behavior of lanthanum in root tips excized from wheat seedlings growing at both promotional and inhibitory levels of LaCl 3 in culture solutions was investigated by a sequential leaching procedure combined with instrumental neutron activation analysis. The results indicate that most of La exists in non-exchangeable species and the binding of La 3+ to the root tips is extremely stable. The root tips during growing at the inhibitory level of LaCl 3 absorb much more La than those at the promotional level. However, the La proportion in each fraction is similar for both groups. (author)

  14. Albumin-induced circular dichroism in Congo red: Applications for studies of amyloid-like fibril aggregates and binding sites.

    Science.gov (United States)

    de Vasconcelos, Débora Naliati; Ximenes, Valdecir Farias

    2015-01-01

    Congo red (CR), one of the most commonly used dyes for the identification of amyloid fibril aggregates, is also a ligand of native bovine serum albumin (BSA). Induced circular dichroism (ICD) is a phenomenon observed when a chiral compound induces chirality in an achiral one. Here, we study the spectral properties and analytical applications of ICD in Congo red provoked by its interaction with BSA. The complex BSA:CR displays a strong ICD spectrum with a positive band at 412 nm and two negative bands at 356 and 490 nm. The use of site I and site II albumin ligands as warfarin and ibuprofen, respectively, provoked different alterations in the Congo red ICD spectrum. The BSA binding sites were modified by oxidation and the ICD signal was sensitive to this alteration. The thermal treatment of the BSA:CR complex (30-90 °C) was monitored by ICD at 490 nm and showed a sigmoidal pattern typical of phase transition in proteins. The altered ICD spectrum is consistent with the formation of amyloid-like fibril aggregates in BSA, which was confirmed by thioflavin T and Rayleigh scattering assays. In conclusion, the ICD provoked by the binding of Congo red to albumin may represent a new spectroscopic technique for studying alterations in the structure of albumin regarding its binding sites and the formation of amyloid aggregates. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Molecular mechanism of allosteric modulation at GPCRs: insight from a binding kinetics study at the human A1 adenosine receptor.

    Science.gov (United States)

    Guo, Dong; Venhorst, Suzanne N; Massink, Arnault; van Veldhoven, Jacobus P D; Vauquelin, Georges; IJzerman, Adriaan P; Heitman, Laura H

    2014-12-01

    Many GPCRs can be allosterically modulated by small-molecule ligands. This modulation is best understood in terms of the kinetics of the ligand-receptor interaction. However, many current kinetic assays require at least the (radio)labelling of the orthosteric ligand, which is impractical for studying a range of ligands. Here, we describe the application of a so-called competition association assay at the adenosine A1 receptor for this purpose. We used a competition association assay to examine the binding kinetics of several unlabelled orthosteric agonists of the A1 receptor in the absence or presence of two allosteric modulators. We also tested three bitopic ligands, in which an orthosteric and an allosteric pharmacophore were covalently linked with different spacer lengths. The relevance of the competition association assay for the binding kinetics of the bitopic ligands was also explored by analysing simulated data. The binding kinetics of an unlabelled orthosteric ligand were affected by the addition of an allosteric modulator and such effects were probe- and concentration-dependent. Covalently linking the orthosteric and allosteric pharmacophores into one bitopic molecule had a substantial effect on the overall on- or off-rate. The competition association assay is a useful tool for exploring the allosteric modulation of the human adenosine A1 receptor. This assay may have general applicability to study allosteric modulation at other GPCRs as well. © 2014 The British Pharmacological Society.

  16. In vitro study on binding interaction of quinapril with bovine serum albumin (BSA) using multi-spectroscopic and molecular docking methods.

    Science.gov (United States)

    Shi, Jie-Hua; Pan, Dong-Qi; Jiang, Min; Liu, Ting-Ting; Wang, Qi

    2017-08-01

    The binding interaction between quinapril (QNPL) and bovine serum albumin (BSA) in vitro has been investigated using UV absorption spectroscopy, steady-state fluorescence spectroscopic, synchronous fluorescence spectroscopy, 3D fluorescence spectroscopy, Fourier transform infrared spectroscopy, circular dichroism, and molecular docking methods for obtaining the binding information of QNPL with BSA. The experimental results confirm that the quenching mechanism of the intrinsic fluorescence of BSA induced by QNPL is static quenching based on the decrease in the quenching constants of BSA in the presence of QNPL with the increase in temperature and the quenching rates of BSA larger than 10 10  L mol -1  s -1 , indicating forming QNPL-BSA complex through the intermolecular binding interaction. The binding constant for the QNPL-BSA complex is in the order of 10 5  M -1 , indicating there is stronger binding interaction of QNPL with BSA. The analysis of thermodynamic parameters together with molecular docking study reveal that the main binding forces in the binding process of QNPL with BSA are van der Waal's forces and hydrogen bonding interaction. And, the binding interaction of BSA with QNPL is an enthalpy-driven process. Based on Förster resonance energy transfer, the binding distance between QNPL and BSA is calculated to be 2.76 nm. The results of the competitive binding experiments and molecular docking confirm that QNPL binds to sub-domain IIA (site I) of BSA. It is confirmed there is a slight change in the conformation of BSA after binding QNPL, but BSA still retains its secondary structure α-helicity.

  17. Preoperative screening: value of previous tests.

    Science.gov (United States)

    Macpherson, D S; Snow, R; Lofgren, R P

    1990-12-15

    To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.

  18. Feature- and Face-Exchange illusions: New insights and applications for the study of the binding problem

    Directory of Open Access Journals (Sweden)

    Arthur Gilman Shapiro

    2014-10-01

    Full Text Available The binding problem is a longstanding issue in vision science: i.e., how are humans able to maintain a relatively stable representation of objects and features even though the visual system processes many aspects of the world separately and in parallel? We previously investigated this issue with a variant of the bounce-pass paradigm, which consists of two rectangular bars moving in opposite directions; if the bars are identical and never overlap, the motion could equally be interpreted as bouncing or passing. Although bars of different colors should be seen as passing each other (since the colors provide more information about the bars’ paths, we found Feature Exchange: observers reported the paradoxical perception that the bars appear to bounce off of each other and exchange colors. Here we extend our previous findings with three demonstrations. Peripheral Feature-Exchange consists of two colored bars that physically bounce (they continually meet in the middle of the monitor and return to the sides. When viewed in the periphery, the bars appear to stream past each other even though this percept relies on the exchange of features and contradicts the information provided by the color of the bars. In Face-Exchange two different faces physically pass each other. When fixating centrally, observers typically report the perception of bouncing faces that swap features, indicating that the Feature Exchange effect can occur even with complex objects. In Face-Go-Round, one face repeatedly moves from left to right on the top of the monitor, and the other from right to left at the bottom of the monitor. Observers typically perceive the faces moving in a circle--a percept that contradicts information provided by the identity of the faces. We suggest that Feature Exchange and the paradigms used to elicit it can be useful for the investigation of the binding problem as well as other contemporary issues of interest to vision science.

  19. The Binding Effect of Proteins on Medications and Its Impact on Electrochemical Sensing: Antipsychotic Clozapine as a Case Study

    Directory of Open Access Journals (Sweden)

    George E. Banis

    2017-08-01

    Full Text Available Clozapine (CLZ, a dibenzodiazepine, is demonstrated as the optimal antipsychotic for patients suffering from treatment-resistant schizophrenia. Like many other drugs, understanding the concentration of CLZ in a patient’s blood is critical for managing the patients’ symptoms, side effects, and overall treatment efficacy. To that end, various electrochemical techniques have been adapted due to their capabilities in concentration-dependent sensing. An open question associated with electrochemical CLZ monitoring is whether drug–protein complexes (i.e., CLZ bound to native blood proteins, such as serum albumin (SA or alpha-1 acid-glycoprotein (AAG contribute to electrochemical redox signals. Here, we investigate CLZ-sensing performance using fundamental electrochemical methods with respect to the impact of protein binding. Specifically, we test the activity of bound and free fractions of a mixture of CLZ and either bovine SA or human AAG. Results suggest that bound complexes do not significantly contribute to the electrochemical signal for mixtures of CLZ with AAG or SA. Moreover, the fraction of CLZ bound to protein is relatively constant at 31% (AAG and 73% (SA in isolation with varying concentrations of CLZ. Thus, electrochemical sensing can enable direct monitoring of only the unbound CLZ, previously only accessible via equilibrium dialysis. The methods utilized in this work offer potential as a blueprint in developing electrochemical sensors for application to other redox-active medications with high protein binding more generally. This demonstrates that electrochemical sensing can be a new tool in accessing information not easily available previously, useful toward optimizing treatment regimens.

  20. Substituting random forest for multiple linear regression improves binding affinity prediction of scoring functions: Cyscore as a case study.

    Science.gov (United States)

    Li, Hongjian; Leung, Kwong-Sak; Wong, Man-Hon; Ballester, Pedro J

    2014-08-27

    State-of-the-art protein-ligand docking methods are generally limited by the traditionally low accuracy of their scoring functions, which are used to predict binding affinity and thus vital for discriminating between active and inactive compounds. Despite intensive research over the years, classical scoring functions have reached a plateau in their predictive performance. These assume a predetermined additive functional form for some sophisticated numerical features, and use standard multivariate linear regression (MLR) on experimental data to derive the coefficients. In this study we show that such a simple functional form is detrimental for the prediction performance of a scoring function, and replacing linear regression by machine learning techniques like random forest (RF) can improve prediction performance. We investigate the conditions of applying RF under various contexts and find that given sufficient training samples RF manages to comprehensively capture the non-linearity between structural features and measured binding affinities. Incorporating more structural features and training with more samples can both boost RF performance. In addition, we analyze the importance of structural features to binding affinity prediction using the RF variable importance tool. Lastly, we use Cyscore, a top performing empirical scoring function, as a baseline for comparison study. Machine-learning scoring functions are fundamentally different from classical scoring functions because the former circumvents the fixed functional form relating structural features with binding affinities. RF, but not MLR, can effectively exploit more structural features and more training samples, leading to higher prediction performance. The future availability of more X-ray crystal structures will further widen the performance gap between RF-based and MLR-based scoring functions. This further stresses the importance of substituting RF for MLR in scoring function development.

  1. Characterization of the β-lactam binding site of penicillin acylase of Escherichia coli by structural and site-directed mutagenesis studies

    NARCIS (Netherlands)

    Alkema, Wynand B.L.; Hensgens, Charles M.H.; Kroezinga, Els H.; de Vries, Erik; Floris, René; Laan, Jan-Metske van der; Dijkstra, Bauke W.; Janssen, Dick B.

    2000-01-01

    The binding of penicillin to penicillin acylase was studied by X-ray crystallography. The structure of the enzyme–substrate complex was determined after soaking crystals of an inactive βN241A penicillin acylase mutant with penicillin G. Binding of the substrate induces a conformational change, in

  2. Characterization of the beta-lactam binding site of penicillin acylase of Escherichia coli by structural and site-directed mutagenesis studies

    NARCIS (Netherlands)

    Alkema, WBL; Hensgens, CMH; Kroezinga, EH; de Vries, E; Floris, R; van der Laan, JM; Dijkstra, BW; Janssen, DB

    2000-01-01

    The binding of penicillin to penicillin acylase was studied by X-ray crystallography, The structure of the enzyme-substrate complex was determined after soaking crystals of an inactive beta N241A penicillin acylase mutant with penicillin G, Binding of the substrate induces a conformational change,

  3. 2'-C-Methyl analogues of selective adenosine receptor agonists: synthesis and binding studies.

    Science.gov (United States)

    Franchetti, P; Cappellacci, L; Marchetti, S; Trincavelli, L; Martini, C; Mazzoni, M R; Lucacchini, A; Grifantini, M

    1998-05-07

    2'-C-Methyl analogues of selective adenosine receptor agonists such as (R)-PIA, CPA, CCPA, NECA, and IB-MECA were synthesized in order to further investigate the subdomain that binds the ribose moiety. Binding affinities of these new compounds at A1 and A2A receptors in bovine brain membranes and at A3 in rat testis membranes were determined and compared. It was found that the 2'-C-methyl modification resulted in a decrease of the affinity, particularly at A2A and A3 receptors. When such modification was combined with N6-substitutions with groups which induce high potency and selectivity at A1 receptors, the high affinity was retained and the selectivity was increased. Thus, 2-chloro-2'-C-methyl-N6-cyclopentyladenosine (2'-Me-CCPA), which displayed a Ki value of 1.8 nM at A1 receptors, was selective for A1 vs A2A and A3 receptors by 2166- and 2777-fold, respectively, resulting in one of the most potent and A1-selective agonists so far known. In functional assay, this compound inhibited forskolin-stimulated adenylyl cyclase activity with an IC50 value of 13.1 nM, acting as a full agonist.

  4. Exploring the binding site of the human muscarinic M3 receptor: Homology modeling and docking study

    Science.gov (United States)

    Ostopovici, Liliana; Mracec, Maria; Mracec, Mircea; Borota, Ana

    The human muscarinic M3 receptor (hM3) and its interactions with selective agonists and antagonists were investigated by means of combined homology and docking approach. Also, two pharmacophoric models for the hM3 agonist and antagonist binding sites were proposed. The three-dimensional (3D) structure of hM3 receptor was modeled based on the high-resolution X-ray structure of bovine rhodopsin from the Protein Data Bank (PDB). To validate the reli