988 resultados para Crick, Francis H. C
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Chronic hepatitis C virus (HCV) infection exists in a large proportion of patients undergoing renal transplantation. Nowadays it is not considered to be an absolute contraindication to transplantation; however, it is associated with an increased risk for the patient and accounts for a shorter half-life of the renal allograft. We present three transplant recipients who displayed serious hepatic dysfunction after renal transplantation due to an HCV infection. In two of these cases, the liver biopsies established the diagnosis of FCH. In the third case, the liver biopsy was compatible with the early stages of FCH. All patients were started on peg-interferon alfa 2-b and ribavirin with subsequent normalization of hepatic function and early complete viral responses.
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It is generally agreed that the hepatitis C virus (HCV) can be efficiently transmitted parenterally, although data on viral transmission by sexual or non-sexual intrafamilial contact are conflicting. Since data collection began in 1989, the first study dealt with the risk of sexual transmission among multiple sex partners. Other investigations followed, emphasizing that risk increases in specific groups such as patients co-infected with HIV and HBV, sex workers, homosexuals, illicit drug users and patients attended at sexually transmittable disease clinics. The question arises as to what might be the risk for monogamous heterosexuals in the general population, in which one of the partners has HCV? The literature provides overall rates that vary from zero to 27%; however, most studies affirm that the chances of sexual transmission are low or almost null, with rates for this mode fluctuating from zero to 3%. Intrafamilial transmission is strongly considered but inconclusive, since when mentioning transmission between sex partners within the same household, specific situations also should be considered, such as the sharing of personal hygiene items, like razorblades, toothbrushes, nail clippers and manicure pliers, which are important risk factors in HCV transmission. In this review, we discuss the hypotheses of sexual and/or intrafamilial transmission.
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BACKGROUND: The pathogenesis of chronic hepatitis C is still a matter of debate. CD4+ and CD8+ T lymphocytes (TL) are typically observed within the portal and periportal spaces of affected livers, but their functional role in hepatitis C progression has not been fully elucidated. METHODS: CD4+ and CD8+ TL were quantified by immunohistochemistry in portal and periportal spaces of 39 liver biopsies from patients with chronic hepatitis C. They were associated to demographic data, histological parameters, laboratory findings of patients and hepatitis C genotypes. RESULTS: There was high numbers of CD4+ and CD8+ TL from which the density of CD4+ T was higher than CD8+ TL in portal and periportal spaces. CD4+ and CD8+ TL were directly correlated to intensity of interface hepatitis. CD8+ TL correlated to serum enzyme levels. CONCLUSION: The high numbers of CD4+ and CD8+ TL in portal and periportal spaces and their correlation to interface hepatitis suggest that hepatitis C evolution depends on the action of intrahepatic T lymphocytes, lending support to the notion of an immune-mediated mechanism in the pathogenesis of chronic hepatitis C.
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A Mitomicina C está entre uma variedade de agentes quimioterapêuticos intravesicais actualmente disponÃveis para o tratamento do carcinoma superficial da bexiga. Cerca de9% destes doentes desenvolve reacções adversas cutâneas, geralmente dermites de contacto, localizadas nas mãos, pés, genitais, ou erupções mais disseminadas. Descrevem-se 6 casos de dermite de contacto alérgica à Mitomicina C, observados entre Junho/2004 e Março/2005,emcinco doentes do sexo masculino e umdo sexo feminino, com uma idade média de 70 anos.
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In this study, the behaviour of two structural adhesives modified with thermally expandable particles (TEPs) was investigated as a preliminary study for further investigations on the potential of TEPs in adhesive joints. Tensile bulk tests were performed to get the tensile properties of the adhesives and TEPs-modified adhesives. In order to determine the expansion temperature of the particles while encapsulated in these particular adhesive systems, the variation of the volume of adhesive samples modified with different TEPs concentration as a function of temperature was measured. Further, the possibility of any chemical interactions between TEPs and adhesives matrix in the TEPs-modified specimens was verified by a Fourier transform infrared spectroscopy analysis. Finally, the fracture surfaces of the unmodified and TEPs-modified specimens, as well as the dispersion and the morphology of the particles, were examined by a scanning electron microscopy analysis. It was found that the stiffness of the TEPs-modified adhesives is not affected by incorporation of TEPs in the adhesives matrix, while the tensile yield strength decreased by increasing the wt% TEPs content. In applications of such particular materials (TEPs-modified adhesives), the temperature should be controlled to stay between 90°C and 120°C in order to obtain the highest expansion ratio. At a lower temperature, not all the particles will expand, and above, the TEPs will deteriorate and as a result the TEPs-modified adhesives will deteriorate.
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Hepatitis C virus (HCV) is an important factor contributing to morbidity and mortality in patients co-infected with HIV and HCV. In addition, liver biopsy is an important tool in the clinical management of these patients. Although liver biopsy is controversial, it is recommended for all patients. Data regarding the clinical and histological characteristics of these patients are scarce not only in Brazil but in Latin America as a whole. With the goal of better understanding these characteristics and the benefit of liver biopsy indications in this disease setting, data collected from 234 patients followed from 1996 to 2004 at Casa da AIDS, São Paulo, were analyzed. The following variables were extracted from the patients' medical files at the time of liver biopsy: sex, age, hepatitis C infection risk factors, hepatitis C infection duration, ALT levels, CD4+ T cell counts, history of alcohol abuse, history of antiretroviral therapy, HCV genotype, and liver histological alterations. CONCLUSIONS: 1 - Hepatitis C virus 1 and 3 were the most frequently identified genotypes and were diagnosed in 72% and 25.5% of cases respectively; 2 - Structural liver alterations were found to be mild or absent in 48.2% (113/234) of the analyzed patients; 3 - Fifty-three patients (23%) had normal ALT levels and 4 - Significant liver architectural changes (F2-F3) were evident in 22.5% of the patients with normal ALT levels.
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In order to determine the prevalence of hepatitis C virus (HCV) infection in quilombo remnant communities in Central Brazil, 1,007 subjects were interviewed in all 12 communities existing in Mato Grosso do Sul State, Central Brazil. Blood samples were collected and sera were tested for anti-HCV by enzyme-linked immunosorbent assay. Positive samples were retested for confirmation using a line immunoassay and were also subjected to HCV RNA detection. The prevalence of HCV infection was 0.2%. This finding shows a low prevalence of HCV infection in quilombo remnant communities in Central Brazil.
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Because of the scientific evidence showing that arsenic (As), cadmium (Cd), and nickel (Ni) are human genotoxic carcinogens, the European Union (EU) recently set target values for metal concentration in ambient air (As: 6 ng/m3, Cd: 5 ng/m3, Ni: 20 ng/m3). The aim of our study was to determine the concentration levels of these trace elements in Porto Metropolitan Area (PMA) in order to assess whether compliance was occurring with these new EU air quality standards. Fine (PM2.5) and inhalable (PM10) air particles were collected from October 2011 to July 2012 at two different (urban and suburban) locations in PMA. Samples were analyzed for trace elements content by inductively coupled plasma–mass spectrometry (ICP-MS). The study focused on determination of differences in trace elements concentration between the two sites, and between PM2.5 and PM10, in order to gather information regarding emission sources. Except for chromium (Cr), the concentration of all trace elements was higher at the urban site. However, results for As, Cd, Ni, and lead (Pb) were well below the EU limit/target values (As: 1.49 ± 0.71 ng/m3; Cd: 1.67 ± 0.92 ng/m3; Ni: 3.43 ± 3.23 ng/m3; Pb: 17.1 ± 10.1 ng/m3) in the worst-case scenario. Arsenic, Cd, Ni, Pb, antimony (Sb), selenium (Se), vanadium (V), and zinc (Zn) were predominantly associated to PM2.5, indicating that anthropogenic sources such as industry and road traffic are the main source of these elements. High enrichment factors (EF > 100) were obtained for As, Cd, Pb, Sb, Se, and Zn, further confirming their anthropogenic origin.
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Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores
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Context: Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer. Objective: A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation. Materials and methods: Physical, microbiological and functional stability were evaluated during 6 months storage at 20 °C and 40 °C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed. Results and discussion: Minor changes were observed in the textural and rheological properties of the formulation when stored at 20 °C for 6 months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610 ± 70 µgh−0.5) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4 h after product’s application. Conclusion: The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.
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Toxic effects of ultraviolet (UV) radiation on skin include protein and lipid oxidation, and DNA damage. The latter is known to play a major role in photocarcinogenesis and photoaging. Many plant extracts and natural compounds are emerging as photoprotective agents. Castanea sativa leaf extract is able to scavenge several reactive species that have been associated to UV-induced oxidative stress. The aim of this work was to analyze the protective effect of C. sativa extract (ECS) at different concentrations (0.001, 0.01, 0.05 and 0.1 μg/mL) against the UV mediated-DNA damage in a human keratinocyte cell line (HaCaT). For this purpose, the cytokinesis-block micronucleus assay was used. Elucidation of the protective mechanism was undertaken regarding UV absorption, influence on 1O2 mediated effects or NRF2 activation. ECS presented a concentration-dependent protective effect against UV-mediated DNA damage in HaCaT cells. The maximum protection afforded (66.4%) was achieved with the concentration of 0.1 μg/mL. This effect was found to be related to a direct antioxidant effect (involving 1O2) rather than activation of the endogenous antioxidant response coordinated by NRF2. Electrochemical studies showed that the good antioxidant capacity of the ECS can be ascribed to the presence of a pool of different phenolic antioxidants. No genotoxic or phototoxic effects were observed after incubation of HaCaT cells with ECS (up to 0.1 μg/mL). Taken together these results reinforce the putative application of this plant extract in the prevention/minimization of UV deleterious effects on skin.
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Hepatitis C virus (HCV) and human T-cell lymphotropic virus type 1 (HTLV-1) share routes of transmission and some individuals have dual infection. Although some studies point to a worse prognosis of hepatitis C virus in patients co-infected with HTLV-1, the interaction between these two infections is poorly understood. This study evaluated the influence of HTLV-1 infection on laboratory parameters in chronic HCV patients. Twelve HTLV-1/HCV-coinfected patients were compared to 23 patients infected only with HCV, in regard to demographic data, risk factors for viral acquisition, HCV genotype, presence of cirrhosis, T CD4+ and CD8+ cell counts and liver function tests. There was no difference in regard to age, gender, alcohol consumption, smoking habits, HCV genotype or presence of cirrhosis between the groups. Intravenous drug use was the most common risk factor among individuals co-infected with HTLV-1. These patients showed higher TCD8+ counts (p = 0.0159) and significantly lower median values of AST and ALT (p = 0.0437 and 0.0159, respectively). In conclusion, we have shown that HCV/HTLV-1 co-infected patients differs in laboratorial parameters involving both liver and immunological patterns. The meaning of these interactions in the natural history of these infections is a matter that deserves further studies.
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The complex interaction between hepatitis C virus infection, iron homeostasis and the response to antiviral treatment remains controversial. The aim of this study was to evaluate the influence of hepatic iron concentration (HIC) on the sustained virological response (SVR) to antiviral therapy in patients with chronic hepatitis C. A total of 50 patients who underwent pretreatment liver biopsy with assessment of HIC by graphite furnace atomic absorption spectroscopy and were subsequently submitted to antiviral treatment with interferon/peginterferon and ribavirin were included in the study. Patients with alcoholism, history of multiple blood transfusion, chronic kidney disease, hemolytic anemia and parenteral iron therapy were excluded. The iron related markers and HIC were compared between those who achieved an SVR and non-responders (NR) patients. The mean age was 45.7 years and the proportion of patients' gender was not different between SVR and NR patients. The median serum iron was 138 and 134 µg/dL (p = 0.9), the median serum ferritin was 152.5 and 179.5 ng/mL (p = 0.87) and the median HIC was 9.9 and 8.2 µmol/g dry tissue (p = 0.51), for SVR and NR patients, respectively. Thus, hepatic iron concentration, determined by a reliable quantitative method, was not a negative predictive factor of SVR in patients with chronic hepatitis C presenting mild to moderate hepatic iron accumulation.
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Hepatitis C virus (HCV) genotypes and subtypes were determined in hemodialysis patients in the Federal District, Brazil, by sequencing of the 5' noncoding (NC) and nonstructural 5B (NS5B) regions. From 761 patients, 66 anti-HCV-positive samples were tested for HCV RNA. All 51 HCV RNA-positive samples by PCR of the 5' NC region were genotyped as genotypes 1 (90.2%) and 3 (9.8%). Subtype 1a (82.3%) was the most prevalent, followed by subtypes 3a (9.8%), 1b (5.9%) and 1a/1b (2.0%). Forty-two samples could be amplified and genotyped in the NS5B region: 38 (90.5%) as genotype 1, subtypes 1a, and 8 (9.5%) as genotype 3, subtype 3a. For the 42 samples sequenced in both regions, the genotypes and subtypes determined were concordant in 100% and 95.2% of cases, respectively. Two samples presented discrepant results, with the 5' NC region not distinguishing correctly the subtypes 1a and 1b. These findings indicate that the HCV genotype 1, subtype 1a, is the most prevalent among hemodialysis patients in the Federal District, Brazil.