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91.
In this paper we demonstrate that the sequence encoded by exon 28 (EX28) of human tropoelastin gene is able to give amyloid-like fibrils. CD (circular dichroism) in solution and solid-state FTIR (Fourier transform infrared spectroscopy) spectroscopies have shown the presence of beta-sheet conformation. At the supramolecular level the fibers formed by EX28 peptide were investigated by AFM (atomic force microscopy) and ESEM (environmental scanning electron microscopy). A very big left-handed helix, 100 mum long, is visible together with aggregates of different sizes, some of them being constituted by helically interwoven fibers. Furthermore, an additional AFM image of EX28 is shown where the ultrastructure found is somewhat reminiscent of a more or less retiform film. These findings should be useful for designing proper elastin-inspired biomaterials. 相似文献
92.
Okudan N Nurullahoğlu-Atalık KE Revan S Belviranlı M Balcı ŞS Gökbel H Pepe H 《Acta physiologica Hungarica》2012,99(1):40-50
In this study, the effect of long-term supplementation of coenzyme Q10 (CoQ10) on the responses of swim-trained rat aorta was investigated. Twenty-four adult male Wistar rats were divided into four groups: untrained, trained, untrained+CoQ10, and trained+CoQ10 group. In the trained groups rats swam for 60 min/day, five days/week for six weeks. The CoQ10 supplements were administered by intraperitoneal injection at a daily dose of 10 mg·kg-1 of body weight five days/week for six weeks. Swimming of the rats was performed in a container containing tap water. Rats were sacrificed and thoracic aortas were removed for ex vivo analysis after the last swimming session. The aortas were cut into rings 2.5 mm in length. Concentration-response curves for phenylephrine (PHE, 10-9-3×10-4 M) and potassium chloride (KCl, 5-100 mM) were isometrically recorded. The sensitivity and maximal responses to PHE and KCl of aortic rings obtained from trained rats were lower than those of untrained rats. CoQ10 supplementation decreased the responses to both vasoconstrictors in untrained and especially in trained groups. Although neither CoQ10 nor training did affect malondialdehyde (MDA) and protein carbonyl (PC) levels, creatine kinase (CK) activity decreased and superoxide dismutase (SOD) activity increased only with exercise training. Glutathione (GSH) levels increased in CoQ10 supplemented-untrained rats. In conclusion, our results suggest that CoQ10 supplementation may have beneficial effects during exercise. 相似文献
93.
Combining predictors for classification using the area under the receiver operating characteristic curve 总被引:1,自引:0,他引:1
No single biomarker for cancer is considered adequately sensitive and specific for cancer screening. It is expected that the results of multiple markers will need to be combined in order to yield adequately accurate classification. Typically, the objective function that is optimized for combining markers is the likelihood function. In this article, we consider an alternative objective function-the area under the empirical receiver operating characteristic curve (AUC). We note that it yields consistent estimates of parameters in a generalized linear model for the risk score but does not require specifying the link function. Like logistic regression, it yields consistent estimation with case-control or cohort data. Simulation studies suggest that AUC-based classification scores have performance comparable with logistic likelihood-based scores when the logistic regression model holds. Analysis of data from a proteomics biomarker study shows that performance can be far superior to logistic regression derived scores when the logistic regression model does not hold. Model fitting by maximizing the AUC rather than the likelihood should be considered when the goal is to derive a marker combination score for classification or prediction. 相似文献
94.
D. Tintar V. Samouillan J. Dandurand C. Lacabanne A. Pepe B. Bochicchio Antonio M. Tamburro 《Biopolymers》2009,91(11):943-952
Calorimetric studies were performed on exon 6 in powdered form and in solution [water and 2,2,2‐trifluoroethanol (TFE), a structure‐inducing solvent or cosolvent]. Dynamic dielectric spectroscopy (DDS) analyses were realized in water and 20% TFE. The major role of solvent–peptide organization is evidenced with these techniques. Calorimetric measurements reveal the structural water organization around the polypeptide as well as the presence of hydrophobic interactions in TFE solution. Dielectric measurements showed for exon 6/water a decrease of relaxations times of bulk solvent implying a faster dynamics with a slight increase of the activation entropy, suggesting that exon 6 probably creates disorder within the solvent. For TFE/water mixtures, an influence of exon 6 on its environment was seen with a relaxation associated with the exon 6/solvent interactions reinforced by storage of 72 h. Finally, exon 6/solvent interactions were clearly observed with additionof TFE. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 943–952, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com 相似文献
95.
Eva Maria Feny? Alan Heath Stefania Dispinseri Harvey Holmes Paolo Lusso Susan Zolla-Pazner Helen Donners Leo Heyndrickx Jose Alcami Vera Bongertz Christian Jassoy Mauro Malnati David Montefiori Christiane Moog Lynn Morris Saladin Osmanov Victoria Polonis Quentin Sattentau Hanneke Schuitemaker Ruengpung Sutthent Terri Wrin Gabriella Scarlatti 《PloS one》2009,4(2)
Background
Neutralizing antibody assessments play a central role in human immunodeficiency virus type-1 (HIV-1) vaccine development but it is unclear which assay, or combination of assays, will provide reliable measures of correlates of protection. To address this, an international collaboration (NeutNet) involving 18 independent participants was organized to compare different assays.Methods
Each laboratory evaluated four neutralizing reagents (TriMab, 447-52D, 4E10, sCD4) at a given range of concentrations against a panel of 11 viruses representing a wide range of genetic subtypes and phenotypes. A total of 16 different assays were compared. The assays utilized either uncloned virus produced in peripheral blood mononuclear cells (PBMCs) (virus infectivity assays, VI assays), or their Env-pseudotyped (gp160) derivatives produced in 293T cells (PSV assays) from molecular clones or uncloned virus. Target cells included PBMC and genetically-engineered cell lines in either a single- or multiple-cycle infection format. Infection was quantified by using a range of assay read-outs that included extracellular or intracellular p24 antigen detection, RNA quantification and luciferase and beta-galactosidase reporter gene expression.Findings
PSV assays were generally more sensitive than VI assays, but there were important differences according to the virus and inhibitor used. For example, for TriMab, the mean IC50 was always lower in PSV than in VI assays. However, with 4E10 or sCD4 some viruses were neutralized with a lower IC50 in VI assays than in the PSV assays. Inter-laboratory concordance was slightly better for PSV than for VI assays with some viruses, but for other viruses agreement between laboratories was limited and depended on both the virus and the neutralizing reagent.Conclusions
The NeutNet project demonstrated clear differences in assay sensitivity that were dependent on both the neutralizing reagent and the virus. No single assay was capable of detecting the entire spectrum of neutralizing activities. Since it is not known which in vitro assay correlates with in vivo protection, a range of neutralization assays is recommended for vaccine evaluation. 相似文献96.
The classification accuracy of a continuous marker is typically evaluated with the receiver operating characteristic (ROC) curve. In this paper, we study an alternative conceptual framework, the "percentile value." In this framework, the controls only provide a reference distribution to standardize the marker. The analysis proceeds by analyzing the standardized marker in cases. The approach is shown to be equivalent to ROC analysis. Advantages are that it provides a framework familiar to a broad spectrum of biostatisticians and it opens up avenues for new statistical techniques in biomarker evaluation. We develop several new procedures based on this framework for comparing biomarkers and biomarker performance in different populations. We develop methods that adjust such comparisons for covariates. The methods are illustrated on data from 2 cancer biomarker studies. 相似文献
97.
98.
Expression of estrogen receptors alpha and beta in the fetal baboon testis and epididymis 总被引:3,自引:0,他引:3
Albrecht ED Billiar RB Aberdeen GW Babischkin JS Pepe GJ 《Biology of reproduction》2004,70(4):1106-1113
99.
In multiple sulfatase deficiency (MSD), a human inherited disorder, the activities of all sulfatases are impaired due to a defect in posttranslational modification. Here we report the identification, by functional complementation using microcell-mediated chromosome transfer, of a gene that is mutated in MSD and is able to rescue the enzymatic deficiency in patients' cell lines. Functional conservation of this gene was observed among distantly related species, suggesting a critical biological role. Coexpression of SUMF1 with sulfatases results in a strikingly synergistic increase of enzymatic activity, indicating that SUMF1 is both an essential and a limiting factor for sulfatases. These data have profound implications on the feasibility of enzyme replacement therapy for eight distinct inborn errors of metabolism. 相似文献
100.