963 resultados para Hepatitis, Viral
Resumo:
Hepatic viscerotomy of paraffin-preserved old specimens, collected in the period from 1934 to 1967, were analyzed by immunohistochemical assays to detect hepatitis B, hepatitis D, dengue and yellow fever virus antigens. The material belongs to the Yellow Fever Collection, Department of Pathology, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil and the cases were diagnosed at that time according to clinical aspects and histopathological findings reporting viral hepatitis, yellow fever, focal necrosis and hepatic atrophy. From the 79 specimens, 69 were collected at the Labrea Region and the other 10 in different other localities in the Amazon Region. The five micra thick histological slices were analyzed for the presence of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) by immunoperoxidase technique. An immunofluorescence assay was applied to the detection of hepatitis D, yellow fever and dengue virus antigens. Nine (11.4%) histological samples were HBsAg reactive and 5 (6.3%) were HBcAg reactive. The oldest reactive sample was from 1934. Viral antigens related to the other pathologies were not detected in this study. Our results confirm that the methodology described may be used to elucidate the aetiology of hepatitis diseases even after a long time of conservation of the specimens.
Resumo:
L'objectiu va ser avaluar la persistència de resposta viral sostinguda als 5 anys de seguiment en pacients amb hepatitis crònica per virus C tractats amb interferó pegilat i ribavirina. Des d'agost de 2001 fins a maig de 2004, es van incloure tots els pacients del nostre centre tractats amb interferó pegilat i ribavirina que van assolir resposta viral sostinguda. Es van recollir dades demogràfiques, histològiques, bioquímics i virològiques durant el tractament i als 5 anys d'haver obtingut la resposta viral sostinguda. Només un dels pacients va presentar recurrència virològica (taxa de recurrència viral a llarg termini molt baixa).
Resumo:
Hepatitis D virus (HDV) is a subviral agent which depends on the envelope proteins (HBsAg) of hepatitis B virus (HBV). Therefore, hepatitis D is observed only in patients infected with HBV. Chronic hepatitis D is the least frequent albeit most severe form of chronic viral hepatitis. A resurgence of chronic hepatitis D has been observed in Northern and Central Europe, mainly due to immigration of patients from regions with high prevalence. Every HBsAg-positive patient should be screened for concurrent HDV infection. Standard treatment consists of pegylated interferon-alpha for at least one year. Sustained virological response rates are approximately 20%. Liver transplantation should be considered in patients with advanced cirrhosis or limited hepatocellular carcinoma. Preventive measures for hepatitis D are the same as for hepatitis B.
Resumo:
Outbreaks of gastroenteritis have occurred among consumers of raw or undercooked shellfish harvested from faecally polluted waters. A multiplex reverse transcription-polymerase chain reaction (RT-PCR) was applied for the simultaneous detection of hepatitis A virus (HAV), poliovirus (PV) and simian rotavirus (RV-SA11) and compared with specific primers for each genome sequence. Three amplified DNA products representing HAV (192 bp), PV (394 bp) and RV (278 bp) were identified when positive controls were used. However, when tested on experimentally contaminated raw oysters, this method was not able to detect the three viruses simultaneously. This is probably due to the low concentration of viral RNAs present in oyster extract which were partially lost during the extracts preparation.
Resumo:
BACKGROUND: A growing number of patients with chronic hepatitis B is being treated for extended periods with nucleoside and/or nucleotide analogs. In this context, antiviral resistance represents an increasingly common and complex issue. METHODS: Mutations in the hepatitis B virus (HBV) reverse transcriptase (rt) gene and viral genotypes were determined by direct sequencing of PCR products and alignment with reference sequences deposited in GenBank. RESULTS: Plasma samples from 60 patients with chronic hepatitis B were analyzed since March 2009. The predominant mutation pattern identified in patients with virological breakthrough was rtM204V/I ± different compensatory mutations, conferring resistance to L-nucleosides (lamivudine, telbivudine, emtricitabine) and predisposing to entecavir resistance (n = 18). Complex mutation patterns with a potential for multidrug resistance were identified in 2 patients. Selection of a fully entecavir resistant strain was observed in a patient exposed to lamivudine alone. Novel mutations were identified in 1 patient. Wild-type HBV was identified in 9 patients with suspected virological breakthrough, raising concerns about treatment adherence. No preexisting resistance mutations were identified in treatment-naïve patients (n = 13). Viral genome amplification and sequencing failed in 16 patients, of which only 2 had a documented HBV DNA > 1000 IU/ml. HBV genotypes were D in 28, A in 6, B in 4, C in 3 and E in 3 patients. Results will be updated in August 2010 and therapeutic implications discussed. CONCLUSIONS: With expanding treatment options and a growing number of patients exposed to nucleoside and/or nucleotide analogs, sequence-based HBV antiviral resistance testing is expected to become a cornerstone in the management of chronic hepatitis B.
Resumo:
The liver tissue of a rhesus macaque inoculated with hepatitis C virus (HCV) has been analyzed for the presence of HCV RNA using the technique of in situ hybridization, both at light and electron microscopy levels. The animal was inoculated by the intrasplenic route using a HCV infected autogenic hepatocyte transplant. The serum sample used to infect the hepatocyte cells was characterized by polymerase chain reaction technique and shown to be positive for HCV RNA, genotype 3 with 10(7) RNA copies/ml. In situ hybridization was performed using a complementary negative strand probe made with the specific primer. We were able to detect and localize viral RNA in altered membranes of the rough endoplasmic reticulum of infected liver cells, showing evidence of virus replication in vivo.
Functional Characterization of a n NTPase Activity of the Hepatitis C Virus Nonstructural Protein 4B
Resumo:
Background: Nonstructural p rotein 4 B (NS4B) i s the m asterorganizer of hepatitis C virus (HCV) replication complexformation. It is a multispanning membrane protein that has beenreported to p ossess NTPase activity. This enzymatic functionhas been poorly studied so far and its role in the HCV life cycleis u nknown. T he present w ork-in-progress a ims at validatingand functionally c haracterizing this a ctivity a nd its r ole in t heviral life cycle.Methods: B ioinformatic analyses were performed to i dentifykey residues for site-directed mutagenesis, both in t he contextof s ubgenomic r eplicons a s well as recombinant v iruses.Mutants were investigated with respect to R NA replication andinfectious particle p roduction. In p arallel, expression andpurification of recombinant wild-type and mutant NS4B proteinsare being pursued to characterize enzymatic activity in vitro.Results: B ioinformatic a nalyses revealed t hat p redictedNTPase features are conserved only in H CV NS4B b ut n ot i nNS4B from other Flaviviridae f amily m embers. A laninesubstitutions were designed to target predicted key Walker A, Band C motifs. These substitutions affected RNA replication andinfectious virus production to v arying degrees. Optimization ofrecombinant protein production is i n progress both in b acterialas well as mammalian expression systems.Conclusions: These studies should yield new insights into thefunctions of this hitherto poorly characterized viral nonstructuralprotein and may reveal novel targets for antiviral intervention inthe future.
Resumo:
Background: Infection with the hepatitis C virus (HCV) i s associatedwith hepatic iron accumulation. We performed a comprehensive analysisof serum ferritin levels and of their genetic determinants in thepathogenesis and treatment of patients with chronic hepatitis C enrolledin the Swiss Hepatitis C Cohort Study (SCCS).Methods: Serum ferritin levels at baseline o f therapy with p egylatedinterferon-α ( PEG-IFN-α) and ribavirin or b efore liver biopsy werecorrelated with clinical features of c hronic HCV infection, includingnecroinflammatory activity (N=970), fibrosis (N=980), steatosis (N=886)and response to treatment (N=876). The association b etween highferritin levels (> median) and the endpoints w as assessed b y logisticregression. In addition, a candidate gene analysis as well as a genomewideassociation study (GWAS) of serum ferritin levels were performed.Results: S erum ferritin > sex-specific median was one of the strongestpre-treatment predictors of failure to achieve SVR (P<0.0001, OR=0.46,95% CI=0.34-0.60). This association remained highly significant in amultivariate analysis (P=0.0001, OR=0.32, 95% CI=0.18-0.57), with anodds ratio c omparable to that of IL28B g enotype, and persisted afteradjustment for duration of infection. Additional independent predictors ofnonresponse were viral load, HCV genotype, presence of diabetes, andliver fibrosis stage. Higher serum ferritin levels were also independentlyassociated with severe liver fibrosis (P<0.0001, OR=2.67, 95% CI=1.66-4.28) a nd steatosis (P=0.0034, OR=2.34, 95% CI=1.33-4.12), but n otwith necroinflammatory a ctivity (P=0.3). No significant g eneticdeterminants of serum ferritin levels were identified.Conclusions: Elevated serum ferritin levels are associated withadvanced liver fibrosis, hepatic steatosis, and poor r esponse to IFN-α-based therapy in c hronic hepatitis C, i ndependently from IL28Bgenotype.
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The recent publication of two controlled trials on boceprevir and three on telaprevir heralds a new era for hepatitis C therapy. Bocreprevir and telaprevir are protease inhibitors which act directly on the hepatitis C virus to inhibit replication and are referred to as direct acting antiviral agents (DAAâ?Ts). They are the first 2 such agents to be licensed but it is hoped that many more will soon follow. These are very important studies and represent a major advance in treatment for patients with chronic hepatitis C virus infection. To appreciate their significance it is important to be aware of some of the clinical features of hepatitis C virus infection. Firstly, hepatitis C exposure leads to chronic infection in approximately 70% of patients. Over time (years or decades) this may lead to chronic hepatitis, cirrhosis, liver failure and hepatocellular carcinoma. The speed of progression depends on a number of co-factors. Patients who are male, drink alcohol, are overweight, diabetic or co-infected with HIV have more rapid progression to cirrhosis8. In contrast young, non-drinking females progress more slowly... Many patients with hepatitis C attend drug treatment clinics. This group rarely receive anti-viral therapy but represents the bulk of the population at risk for complications of chronic hepatitis C. It has been shown that antiviral treatment in drug treatment centres, linked to methadone treatment, is very effective in ensuring compliance. As the drug treatment infrastructure already exists, widening its remit to include hepatitis C treatment should be cost effective. A recent large study from the United States confirmed that it is possible to provide effective anti-viral therapy for hepatitis C in primary care settings, provided there is appropriate back-up.
Resumo:
Since the arrival of several new antivirals and due to the growing molecular and clinical knowledge of hepatitis B virus (HBV) infection, therapy of hepatitis B has become complex. Clinical guidelines aim at streamlining medical attitudes: in this respect, the European Association for the Study of the Liver (EASL) recently issued clinical practice guidelines for the management of chronic hepatitis B. Guidelines made by international experts need however to be adapted to local health care systems. Here, we summarise the EASL guidelines with some minor modifications in order to be compatible with the particular Swiss situation, while discussing in more detail some aspects. Chronic hepatitis B is a complex disease with several phases where host and viral factors interact: the features of this continuous interplay need to be evaluated when choosing the most appropriate treatment. The EASL guidelines recommend, as first-line agents, using the most potent antivirals available with the optimal resistance profile, in order to abate HBV DNA as rapidly and as sustainably as possible. Once therapy has been started, the infection evolves and resistant viral strains may emerge. Rescue therapy needs to be started early with more potent agents lacking cross-resistance.
Resumo:
Introduction: Apoptosis plays a central role in chronic hepatitis C virus (HCV) infection. Although the activation of cell death signals has been reported, HCV infection persists in most patients suggesting a pro-survival adaptation, eventually developing hepatocellular carcinoma. This study focused on the role of mitochondria in the activation of pro- and antiapoptotic response in cells expressing HCV proteins. Materials and Methods: Human Osteosarcoma U2-OS cells inducibly expressing the HCV polyprotein; huh7.5 hepatoma cells transfected with full length HCV genome. Results: Long term induction of viral proteins in U2-OS cells induced a cyclosporine A-sensitive cytochrome c partial release from mitochondria, revealed by immunofluorescence, western blot and spectral analysis. In HCV-transfected Huh7.5 cells, release of the apoptosis inducing factor (AIF) with no apparent nuclear translocation was also observed. HCV positive cells displayed an HIF-dependent enhanced glycolysis, charachterized by up-regulation of the mitochondria-bound Hexokinase II (HKII); preliminary data on signal transduction pathway revealed the iperphosphorylation of Glycogen synthase kinase 3b(GSK3b). Conclusion: HCV causes a cell stress activating an early apoptotic response, the entity of which likely depends on the cell type. Nevertheless a wide series of cell survival mechanisms are also triggered resulting in a metabolic adaptation possibly favouring carcinogenesis. Based on our results, we propose a pro-survival mechanism linking HCV infection to inhibition of GSK-3b, stabilization of HIF1a and up-regulation of HKII, the last events causing a glycolytic shift and protecting from apoptosis.
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In this report, we examine the adaptability of commercially available serological kits to detect antibodies markers for viral hepatitis in oral fluid samples. We also assessed the prevalence of hepatitis A, B, and C virus-specific antibodies, and related risk factors for these infectious diseases through sensitivity of the tests in saliva samples to evaluate if oral fluid can be an alternative tool to substitute serum in diagnosis of acute viral hepatitis and in epidemiological studies. One hundred and ten paired serum and saliva specimens from suspect patients of having acute hepatitis were collected to detect antibodies to hepatitis A (total and IgM), hepatitis B (anti-HBs, total anti-HBc and IgM anti-HBc), and hepatitis C (anti-HCV) using commercially available enzyme-linked immunossorbent assay (EIA). In relation to serum samples, oral fluid assay sensitivity and specificity were as follows: 87 and 100% for total anti-HAV, 79 and 100% for anti-HAV IgM, 6 and 95% for anti-HBs, 13 and 100% for total anti-HBc, 100 and 100% for anti-HBc IgM, and 75 and 100% for anti-HCV. The consistency observed between antibodies tests in saliva and expected risk factors for hepatitis A and C suggests that the saliva method could replace serum in epidemiological studies for hepatitis A and C.
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This study investigated the seropositivity for hepatitis B virus (HBV), the vaccination index, and the vaccine response index in dentists from Campo Grande, MS. Blood samples from 474 dentists (63.7% women and 36.3% men), with a mean age of 38.5 ± 10.5 years were analyzed by enzyme-linked immunosorbent assay to detect the serological markers: HBsAg, anti-HBs, and anti-HBc. The HBsAg positive samples were tested for anti-HBc IgM, HBeAg, and anti-HBe. A total of 51 (10.8%) dentists showed seropositivity for HBV. Three (0.6%) were HBsAg/anti-HBc/anti-HBe positive, 43 (9.1%) were anti-HBc/anti-HBs positive, and 5 (1.1%) had only anti-HBc. Viral DNA was detected by polymerase chain reaction in 9 (17.6%) out of 51 HBV seropositive samples. A vaccination index of 96.6% (458/474) was observed, although 73.1% (335/458)completed the three-dose schedule. Excluding 46 HBV seropositive individuals from 458 that reported vaccination, 412 were analyzed for vaccine response index. It was observed that 74.5% (307/412) were anti-HBs positive; this percentage increased to 79.1% when three doses were administered. The results showed a high vaccination index and a good rate of vaccine response; however, the failure in completing the three-dose schedule and the occurrence of HBV infection reinforce the need for more effective prevention strategies.
Resumo:
In this study, a total of 865 serum samples were collected between 1995 and 2002 from individuals living in Goiânia, Central Brazil, and clinically suspected of hepatitis. After exclusion of 162 samples which were positive for hepatitis B virus or hepatitis C virus, 703 samples were tested for anti-hepatitis A virus (anti-HAV) IgM antibodies by enzyme immunoassay. In addition, 588 of these samples and 22 fecal samples were analyzed by reverse transcription-nested PCR for HAV RNA detection, with positivity indices of 13.1% (77/588) and 54.5% (12/22), respectively. A similar index of viral RNA detection in anti-HAV-IgM positive or negative samples was observed in serum samples. HAV infection is a public health problem worldwide and this study underscores the extent of HAV circulation in our region.