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891.
Oliveira AV Gaspar AR Francisco SC Quintela DA 《International journal of biometeorology》2012,56(2):319-332
The present experimental work is dedicated to the analysis of the effect of walking on the thermal insulation of the air layer
(I
a
) and on the convective heat transfer coefficients (h
conv
) of the human body. Beyond the standing static posture, three step rates were considered: 20, 30 and 45 steps/min. This corresponds
to walking speeds of approximately 0.23, 0.34 and 0.51 m/s, respectively. The experiments took place in a climate chamber
with an articulated thermal manikin with 16 independent parts. The indoor environment was controlled through the inner wall
temperatures since the objective of the tests was restricted to the influence of the walking movements under calm conditions.
Five set points were selected: 10, 15, 20, 25 and 30°C, and the operative temperature within the test chamber varied between
11.9 and 29.6°C. The highest and lowest I
a
values obtained were equal to 0.87 and 0.71 clo, respectively, and the reduction in insulation due to walking ranged between
9.8 and 11.5%. The convective coefficients (h
conv
) for the whole body and for the different body segments were also determined for each step rate. In the case of the whole
body, for the standing static reference posture, the mean value of h
conv
was equal to 3.3 W/m2°C and a correlation [Nu = Nu(Gr)] for natural convection is also presented in good agreement with previous results. For the other postures, the values of
h
conv
were equal to 3.7, 3.9 and 4.2 W/m2°C, respectively for 20, 30 and 45 steps/min. 相似文献
892.
Leite CE Teixeira Ada C Cruz FF Concatto SC Amaral JH Bonan CD Campos MM Morrone FB Battastini AM 《Analytical biochemistry》2012,421(2):534-540
Zebrafish are currently used at various stages of the drug discovery process and can be a useful and cost-effective alternative to some mammalian models. Nitric oxide (NO) plays an important role in physiology of zebrafish. The availability of appropriate analytical techniques to quantify the NO is crucial for studying its role in physiological and pathological conditions. This work aimed at establishing a high-performance liquid chromatography method for determination of NO levels in zebrafish larvae. Attempts were also made to assess the normal levels of NO at the first days postfertilization and the possible changes under pathological conditions. The method validation was quantitatively evaluated in terms of sensitivity, specificity, precision, accuracy, linearity, and recovery. NO levels from zebrafish larvae at the first days postfertilization and larvae challenged to N(G)-nitro-L-arginine methyl ester, sodium nitroprusside, Escherichia coli lipopolysaccharide, and copper sulfate were analyzed. The samples were derivatized with 2,3-diaminonaphthalene, and fluorescence detection was used for the indirect determination of NO. The method showed a good performance for all validation parameters evaluated and was efficient to monitor changes in NO concentration under physiological and pathophysiological conditions. This method might represent a powerful tool to be applied in NO studies with zebrafish larvae. 相似文献
893.
Ano Bom AP Rangel LP Costa DC de Oliveira GA Sanches D Braga CA Gava LM Ramos CH Cepeda AO Stumbo AC De Moura Gallo CV Cordeiro Y Silva JL 《The Journal of biological chemistry》2012,287(33):28152-28162
Over 50% of all human cancers lose p53 function. To evaluate the role of aggregation in cancer, we asked whether wild-type (WT) p53 and the hot-spot mutant R248Q could aggregate as amyloids under physiological conditions and whether the mutant could seed aggregation of the wild-type form. The central domains (p53C) of both constructs aggregated into a mixture of oligomers and fibrils. R248Q had a greater tendency to aggregate than WT p53. Full-length p53 aggregated into amyloid-like species that bound thioflavin T. The amyloid nature of the aggregates was demonstrated using x-ray diffraction, electron microscopy, FTIR, dynamic light scattering, cell viabilility assay, and anti-amyloid immunoassay. The x-ray diffraction pattern of the fibrillar aggregates was consistent with the typical conformation of cross β-sheet amyloid fibers with reflexions of 4.7 Å and 10 Å. A seed of R248Q p53C amyloid oligomers and fibrils accelerated the aggregation of WT p53C, a behavior typical of a prion. The R248Q mutant co-localized with amyloid-like species in a breast cancer sample, which further supported its prion-like effect. A tumor cell line containing mutant p53 also revealed massive aggregation of p53 in the nucleus. We conclude that aggregation of p53 into a mixture of oligomers and fibrils sequestrates the native protein into an inactive conformation that is typical of a prionoid. This prion-like behavior of oncogenic p53 mutants provides an explanation for the negative dominance effect and may serve as a potential target for cancer therapy. 相似文献
894.
Bonjardim LR Cunha ES Guimarães AG Santana MF Oliveira MG Serafini MR Araújo AA Antoniolli AR Cavalcanti SC Santos MR Quintans-Júnior LJ 《Zeitschrift für Naturforschung. C, Journal of biosciences》2012,67(1-2):15-21
We attempted to identify the antinociceptive and anti-inflammatory actions of the monoterpene p-cymene. Firstly, behavioural screening was carried out to verify the influence of p-cymene [25, 50, and 100 mg/kg intraperitoneal (i.p.)] on the central nervous system (CNS) activity. The antinociceptive activity of p-cymene was evaluated by the acetic acid-induced writhing response, formalin, and hot-plate test, respectively. The leukocyte migration induced by injection of carrageenan was used to assess the anti-inflammatory activity. p-Cymene showed depressant activity on CNS after 4 h of treatment and also a possible action on the autonomous nervous system (ANS), mainly at the dose of 100 mg/kg (i.p.). It was found that p-cymene (50 and 100 mg/kg, i.p.) significantly (p < 0.05) reduced the writhing responses induced by acetic acid. p-Cymene also decreased the licking time in the first and second phase, respectively, of the formalin test. The results of the hot-plate test showed that all doses of p-cymene increased significantly the latency time of the response to the thermal stimulus in both licking and jumping parameters. In addition, there was a significantly (p < 0.05) decreased leukocyte migration at all doses of p-cymene. The experimental data demonstrate that p-cymene possesses antinociceptive and anti-inflammatory activities. 相似文献
895.
896.
LV Faro JM de Almeida CC Cirne-Santos VA Giongo LR Castello-Branco Ide B Oliveira JE Barbosa AC Cunha VF Ferreira MC de Souza IC Paixão MC de Souza 《Bioorganic & medicinal chemistry letters》2012,22(15):5055-5058
The emergence of a multidrug-resistant HIV-1 strain and the toxicity of anti-HIV-1 compounds approved for clinical use are the most significant problems facing antiretroviral therapies. Therefore, it is crucial to find new agents to overcome these issues. In this study, we synthesized a series of new oxoquinoline acyclonucleoside phosphonate analogues (ethyl 1-[(diisopropoxyphosphoryl)methyl]-4-oxo-1,4-dihydroquinoline-3-carboxylates 3a-3k), which contained different substituents at the C6 or C7 positions of the oxoquinoline nucleus and an N1-bonded phosphonate group. We subsequently investigated these compounds' in vitro inhibitory effects against HIV-1-infected peripheral blood mononuclear cells (PBMCs). The most active compounds were the fluoro-substituted derivatives 3f and 3g, which presented excellent EC(50) values of 0.4±0.2 μM (3f) and 0.2±0.005 μM (3g) and selectivity index values (SI) of 6240 and 14675, respectively. 相似文献
897.
Ferreira SM Domingos GP Ferreira Ddos S Rocha TG Serakides R de Faria Rezende CM Cardoso VN Fernandes SO Oliveira MC 《Bioorganic & medicinal chemistry letters》2012,22(14):4605-4608
Osteomyelitis is an infectious disease located in the bone or bone marrow. Long-circulating and pH-sensitive liposomes containing a technetium-99m-labeled antibiotic, ceftizoxime, (SpHL-(99m)Tc-CF) were developed to identify osteomyelitis foci. Biodistribution studies and scintigraphic images of bone infection or non infection-bearing rats that had been treated with these liposomes were performed. A high accumulation in infectious foci and high values in the target-non target ratio could be observed. These results indicate the potential of SpHL-(99m)Tc-CF as a potential agent for the diagnosis of bone infections. 相似文献
898.
899.
de Castro Côrtes LM de Souza Pereira MC de Oliveira FO Corte-Real S da Silva FS Pereira BA de Fátima Madeira M de Moraes MT Brazil RP Alves CR 《Parasitology》2012,139(2):200-207
Leishmaniasis is a vector-borne disease and an important public health issue. Glycosaminoglycan ligands in Leishmania parasites are potential targets for new strategies to control this disease. We report the subcellular distribution of heparin-binding proteins (HBPs) in Leishmania (Viannia) braziliensis and specific biochemical characteristics of L. (V.) braziliensis HBPs. Promastigotes were fractionated, and flagella and membrane samples were applied to HiTrap Heparin affinity chromatography columns. Heparin-bound fractions from flagella and membrane samples were designated HBP Ff and HBP Mf, respectively. Fraction HBP Ff presented a higher concentration of HBPs relative to HBP Mf, and SDS-PAGE analyses showed 2 major protein bands in both fractions (65 and 55 kDa). The 65 kDa band showed gelatinolytic activity and was sensitive to inhibition by 1,10-phenanthroline. The localization of HBPs on the promastigote surfaces was confirmed using surface plasmon resonance (SPR) biosensor analysis by binding the parasites to a heparin-coated sensor chip; that was inhibited in a dose-dependent manner by pre-incubating the parasites with variable concentrations of heparin, thus indicating distinct heparin-binding capacities for the two fractions. In conclusion, protein fractions isolated from either the flagella or membranes of L. (V.) braziliensis promastigotes have characteristics of metallo-proteinases and are able to bind to glycosaminoglycans. 相似文献
900.
Filgueira FP Lobato NS DosSantos RA Oliveira MA Akamine EH Tostes RC Fortes ZB Carvalho MH 《Life sciences》2012,90(17-18):689-694
AimsInflammation may have an important role in the beginning and in the progress of cardiovascular diseases. Testosterone exerts important effects on vascular function, which is altered in arterial hypertension. Thus, the aim of this study was to evaluate the influence of endogenous testosterone on leukocyte behavior in post-capillary venules of the mesenteric bed of spontaneously hypertensive rats (SHR).Main methods18 week-old intact SHR, castrated SHR and normotensive rats (intact Wistar) were used. Blood pressure was measured by tail plethysmography and serum testosterone levels by ELISA. Leukocyte rolling, adhesion and migration were evaluated in vivo in situ by intravital microscopy.Key findingsCastration significantly reduced blood pressure and reversed the increased leukocyte rolling and adhesion observed in SHRs. Leukocyte counts and other hemodynamic parameters did not differ among groups. SHRs displayed increased protein expression of P-selectin and ICAM-1 in mesenteric venules when compared to intact Wistar. Castration of SHRs restored the protein expression of the cell adhesion molecules.SignificanceThe findings of the present study demonstrate the critical role of endogenous testosterone mediating the effects of hypertension increasing leukocyte–endothelial cell interaction. Increased expression of cell adhesion molecules contribute to the effects of endogenous testosterone promoting increased leukocyte rolling and adhesion in SHRs. 相似文献