172 research outputs found
Detection of latent tuberculosis in immunosuppressed patients with autoimmune diseases: performance of a Mycobacterium tuberculosis antigen-specific interferon gamma assay
No full textOBJECTIVE: To analyse the performance of a new M. tuberculosis-specific interferon gamma (IFNgamma) assay in patients with chronic inflammatory diseases who receive immunosuppressive drugs, including tumour necrosis factor alpha (TNFalpha) inhibitors. METHODS: Cellular immune responses to the M. tuberculosis-specific antigens ESAT-6, CFP-10, TB7.7 were prospectively studied in 142 consecutive patients treated for inflammatory rheumatic conditions. Results were compared with tuberculin skin tests (TSTs). Association of both tests with risk factors for latent M. tuberculosis infection (LTBI) and BCG vaccination were determined and the influence of TNFalpha inhibitors, corticosteroids, and disease modifying antirheumatic drugs (DMARDs) on antigen-specific and mitogen-induced IFNgamma secretion was analysed. RESULTS: 126/142 (89%) patients received immunosuppressive therapy. The IFNgamma assay was more closely associated with the presence of risk factors (odds ratio (OR) = 23.8 (95% CI 5.14 to 110) vs OR = 2.77 (1.22 to 6.27), respectively; p = 0.009), but less associated with BCG vaccination than the TST (OR = 0.47 (95% CI 0.15 to 1.47) vs OR = 2.44 (0.74 to (8.01), respectively; p = 0.025). Agreement between the IFNgamma assay and TST results was low (kappa = 0.17; 95% CI 0.02 to 0.32). The odds for a positive IFNgamma assay strongly increased with increasing prognostic relevance of LTBI risk factors. Neither corticosteroids nor conventional DMARDs significantly affected IFNgamma responses, but the odds for a positive IFNgamma assay were decreased in patients treated with TNFalpha inhibitors (OR = 0.21 (95% CI 0.07 to 0.63), respectively; p = 0.006). CONCLUSIONS: These results demonstrate that the performance of the M. tuberculosis antigen-specific IFNgamma ELISA is better than the classic TST for detection of LTBI in patients receiving immunosuppressive therapy for treatment of systemic autoimmune disorders
Biphenyl substituted lysine derivatives as recognition elements for the matrix metalloproteinases MMP-2 and MMP-9
No full textMatrix metalloproteinases (MMPs) are an important factor in cancer progression and metastasis, especially gelatinases MMP-2 and MMP-9. A simple methodology for their detection and monitoring is highly desirable. Molecular probes have been very widely and successfully applied to study the activity of MMPs in cellular processes in vitro. We thus synthesized a small compound library of MMP-2 and MMP-9 binding probes based on drug molecules and endowed with free amine groups for the functionalization of transducer surfaces. In this study, we combined experimental results obtained by a kinetic fluorogenic peptide substrate cleavage assay with molecular modeling studies in order to assess the ability of the probe to bind to their target enzymes. The synthesized biphenyl substituted lysine derivatives showed IC50-values in the low nanomolar concentration range against MMP-2 (ligands 3a-d: 3 nM to 8 μM, ligands 4a-d: 45 nM to 350 μM) and low micromolar range against MMP-9 (ligands 3a-d: 350 nM to 60 μM, ligands 4a-d: 5 μM to 600 μM), with a selectivity up to more than 160-fold for MMP-2. The experimental results correlated well with molecular modelling with FleXAID and X-score functions. We showed that in our compound series, the side chain remained far away from the S1′ cavity and the ligand for all the docked minima. Ligands 4a-d with their free amine group on the side chain may thus be bound to transducer surfaces for the fabrication of sensors, while retaining their activity against their target enzymes
Natural variations at position 93 of the invariant Va24-Ja18 alpha chain of human iNKT cell TCRs strongly impact on CD1d binding
No full textHuman invariant natural killer T (NKT) cell TCRs bind to CD1d via an "invariant" Vá24-Já18 chain (iNKTá) paired to semi-invariant V?11 chains (iNKTâ). Single-amino acid variations at position 93 (p93) of iNKTá, immediately upstream of the “invariant” CDR3á region, have been reported in a substantial proportion of human iNKT cell clones (4-30%). Although p93, a serine in most human iNKT cell TCRs, makes no contact with CD1d, it could affect CD1d-binding by altering the conformation of the crucial CDR3á loop. By generating recombinant refolded iNKT cell TCRs, we show that natural single-nucleotide variations in iNKTá, translating to serine, threonine, asparagine or isoleucine at p93, exert a powerful effect on CD1d binding, with up to 28-fold differences in affinity between these variants. This effect was observed with CD1d loaded with either the artificial á-galactosylceramide antigens KRN7000 or OCH, or the endogenous glycolipid â-galactosylceramide, and its importance for autoreactive recognition of endogenous lipids was demonstrated by the binding of variant iNKT cell TCR tetramers to cell-surface expressed CD1d. The serine-containing variant showed the strongest CD1d-binding, offering an explanation for its predominance in vivo. Complementary molecular dynamics modeling studies were consistent with an impact of p93 on the conformation of the CDR3á loo
Mobility function after total hip replacement surgery recovery prediction of statistical analysis methods
No full textMatulis G. Mobility function after total hip replacement surgery recovery prediction of statistical analysis methods, master thesis / research adviser: Ph. D. L. Pauliukėnas; Lithuanian University of Health Scien-ces, Faculty of Medicine, Department of Physics, Mathematics and Biophysics. - Kaunas, 2017 - 49 s. The aim: to find basic statistical analysis of prognostic factors that best describes the mobility function recovery after hip replacement surgery. Research objectives: 1. For the purposes of statistical analysis techniques to identify predictors of attributes that best describes the function: 1.1 postural change and maintenance; 1.2 the seizure of items, storage and maintenance; 1.3 turn and move; 1.4 the movement in transportation. 2. For the purposes of statistical analysis methods provide assessment identified mobility features. 3. The results are compared with the control group. Research methods: physical examination, evaluation of certain criteria, questionnaire, statistical data analysis. The questionnaire evaluated for hip mobility, making certain movements. Systematic study material using the statistical software package. The participants: Patients (men and women) from 38 m. up to 87 m. Results: A questionnaire was developed based on the scientific literature. The survey questionnaire prepared by integrating the International Functioning, Disability and Health classification of the questionnaire scales, choosing “I can move freely”, “have difficulty”, “can not move”. The questionnaire we applied in practice. The completed questionnaire by email after 3 weeks was recovered and investigators performed the data analysis. Conclusions: 1.1. The application of statistical methods for the analysis found that postural change and retention of the best predictors of daily operational features. 1.2. It was found that the seizure of items, storage and retention of the best predictors of daily activities characterizing features. 1.3. It was found that the turn and movement of the best predictors of daily activities characterizing features. 1.4. It was found that the movement of transport using the best predictors of daily activities characterizing features. 2. The analysis identified three possible values that describe recovery and provides mobility assessment: “I can move freely”, “have difficulty” and “can not move”. 3. The results confirmed the expediency of the questionnaire
Arizona vs. New Mexico Aggies
No full textLes Westfall jumps for the opening tip with Mike Chaco, Matt Matulis, and Haven Batty looking on
Innate-like control of human iNKT cell autoreactivity via the hypervariable CDR3beta loop
No full textInvariant Natural Killer T cells (iNKT) are a versatile lymphocyte subset with important roles in both host defense and immunological tolerance. They express a highly conserved TCR which mediates recognition of the non-polymorphic, lipid-binding molecule CD1d. The structure of human iNKT TCRs is unique in that only one of the six complementarity determining region (CDR) loops, CDR3beta, is hypervariable. The role of this loop for iNKT biology has been controversial, and it is unresolved whether it contributes to iNKT TCR:CD1d binding or antigen selectivity. On the one hand, the CDR3beta loop is dispensable for iNKT TCR binding to CD1d molecules presenting the xenobiotic alpha-galactosylceramide ligand KRN7000, which elicits a strong functional response from mouse and human iNKT cells. However, a role for CDR3beta in the recognition of CD1d molecules presenting less potent ligands, such as self-lipids, is suggested by the clonal distribution of iNKT autoreactivity. We demonstrate that the human iNKT repertoire comprises subsets of greatly differing TCR affinity to CD1d, and that these differences relate to their autoreactive functions. These functionally different iNKT subsets segregate in their ability to bind CD1d-tetramers loaded with the partial agonist alpha-linked glycolipid antigen OCH and structurally different endogenous beta-glycosylceramides. Using surface plasmon resonance with recombinant iNKT TCRs and different ligand-CD1d complexes, we demonstrate that the CDR3beta sequence strongly impacts on the iNKT TCR affinity to CD1d, independent of the loaded CD1d ligand. Collectively our data reveal a crucial role for CDR3beta for the function of human iNKT cells by tuning the overall affinity of the iNKT TCR to CD1d. This mechanism is relatively independent of the bound CD1d ligand and thus forms the basis of an inherent, CDR3beta dependent functional hierarchy of human iNKT cells
Structure and binding kinetics of three different human CD1d-?-galactosylceramide-specific T cell receptors
No full textInvariant human TCR V?24-J?18+/Vbeta11+ NKT cells (iNKT) are restricted by CD1d-?-glycosylceramides. We analyzed crystal structures and binding characteristics for an iNKT TCR plus two CD1d-?-GalCer-specific Vbeta11+ TCRs that use different TCR Valpha chains. The results were similar to those previously reported for MHC-peptide-specific TCRs, illustrating the versatility of the TCR platform. Docking TCR and CD1d-?-GalCer structures provided plausible insights into their interaction. The model supports a diagonal orientation of TCR on CD1d and suggests that complementarity determining region (CDR)3?, CDR3?, and CDR1? interact with ligands presented by CD1d, whereas CDR2? binds to the CD1d ?1 helix. This docking provides an explanation for the dominant usage of V?11 and V?8.2 chains by human and mouse iNKT cells, respectively, for recognition of CD1d-?-GalCer.Abbreviations used: ?-GalCer, ?-galactosylceramide; CDR, complementarity determining region; CNS, Crystallography and NMR system; DN, double negative; ds, disulfide-linked; iNKT, invariant NKT; J, junctional; PC, phosphatidylcholine; rmsd, root mean square deviation; V, variable.<br/
Discovery and validation of SIRT2 inhibitors based on tenovin-6 : use of a 1H-NMR method to assess deacetylase activity
No full textThe search for potent and selective sirtuin inhibitors continues as chemical tools of this type are of use in helping to assign the function of this interesting class of deacetylases. Here we describe SAR studies starting from the unselective sirtuin inhibitor tenovin-6. These studies identify a sub-micromolar inhibitor that has increased selectivity for SIRT2 over SIRT1 compared to tenovin-6. In addition, a H-1-NMR-based method is developed and used to validate further this class of sirtuin inhibitors. A thermal shift analysis of SIRT2 in the presence of tenovin-6, -43, a control tenovin and the known SIRT2 inhibitor AGK2 is also presented.Peer reviewe
Reproducibility and accuracy of microscale thermophoresis in the NanoTemper Monolith: a multi laboratory benchmark study (European Biophysics Journal, (2021), 50, 3-4, (411-427), 10.1007/s00249-021-01532-6)
No full textThe article “Reproducibility and accuracy of microscale thermophoresis in the NanoTemper Monolith: a multi laboratory benchmark study” written by López-Méndez, B., Baron, B., Brautigam, C. A., Jowitt, T. A., Knauer, S. H., Uebel, S., Williams, M. A., Sedivy, A., Abian, O., Abreu, C., Adamczyk, M., Bal, W., Berger, S., Buell, A. K., Carolis, C., Daviter, T., Fish, A., Garcia-Alai, M., Guenther, C., Hamacek, J., Holková, J., Houser, J., Johnson, C., Kelly, S., Leech, A., Mas, C., Matulis, D., McLaughlin, S. H., Montserret, R., Nasreddine, R., Nehmé, R., Nguyen, Q., Ortega-Alarcón, D., Perez, K., Pirc, K., Piszczek, G., Podobnik, M., Rodrigo, N., Rokov-Plavec, J., Schaefer, S., Sharpe, T., Southall, J., Staunton, D., Tavares, P., Vanek, O., Weyand, M., Wu, D. was originally published Online First without Open Access. After publication in volume 50, issue 3–4, pages 411–427 the author decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed topublishersversionpublishe
Thermal, morphological and mechanical properties of ethyl vanillin immobilized in polyvinyl alcohol by electrospinning process
No full textIn this study, polyvinyl alcohol (PVA) nanofibers with ethyl vanillin as active compound were prepared using electrospinning technique. The final products of electrospinning process were in the form of films consist of nanofibers. PVNethyl vanillin nanofibers, having fibers diameters in the range 100-1700 nm, were successfully electrospun from ethanol/water mixture of PVA and ethyl vanillin. The effects of immobilization process on ethyl vanillin thermal properties were investigated by differential scanning calorimetry (DSC). The results of DSC showed significant influence of immobilization process on thermal properties of ethyl vanillin. It was noticed that melting point of immobilized ethyl vanillin was lower (~55°C) compared to free flavor (~77°C). Our results showed that films based on PVNethyl vanillin nanofibers are mechanically stable
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