Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of GB virus C/hepatitis G virus (GBV-C/HGV) in adult and pediatric liver disease is unclear. We detected serum GBV-C/HGV RNA by reverse transcriptase polymerase chain reaction in 1 (3%) of 38 cholestatic infants, in 4 (4%) of 95 children without liver disease, and in none of 30 children with autoimmune hepatitis. One cholestatic infant had antibodies, presumably maternal, to GBV-C/HGV. Sequence analysis of a nonstructural 3 region fragment suggested that mother-to-infant transmission was the route of infection for the cholestatic infant. The four infected children without liver disease had normal liver function test results and lacked risk factors for bloodborne infections. Thus, the detection of GBV-C/HGV RNA among children with and without liver disease suggests that chronic GBV-C/ HGV infections may be established early in life, possibly by mother-to-infant transmission. This may explain in part the high prevalence of serum GBV-C/HGV RNA and antibodies in healthy adults.
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PMID:A high prevalence of serum GB virus C/hepatitis G virus RNA in children with and without liver disease. 1019 74

The concept of chronic hepatitis induced by alcohol (AL-CH) has not been widely accepted, because AL-CH may be due to non-A-E hepatitis virus in heavy drinkers. Recently, hepatitis G virus (HGV) was identified as a positive-strand RNA virus related to members of the Flaviviridae family. In this study, we determined serum HGV in patients with AL-CH and analyzed the clinicopathological changes after abstinence to evaluate whether AL-CH is caused by alcohol or not. Serum samples were obtained from 16 patients with AL-CH who had neither hepatitis B nor C virus. The diagnosis was confirmed histologically. In eight patients, liver biopsy was performed twice, within 3 days and 4 to 8 weeks after abstinence. The NS3 region of the HGV genome was detected using an reverse transcriptase-polymerase chain reaction method. Serum levels of AST, ALT and gamma-glutamyltranspeptidase were measured once a week sequentially after admission. Serum HGV-RNA was detected in only one patient with AL-CH (6.3%). In all patients, including one patient with HGV, serum levels of AST, ALT and gamma-glutamyltranspeptidase clearly decreased to normal levels after abstinence. Inflammatory activity in the periportal area of patients with actively drinking decreased or disappeared after abstinence for 4 to 8 weeks. These results suggest that HGV may not play an important role for development of AL-CH, and that AL-CH may be caused by alcohol itself, although a more larger number of patients with AL-CH are needed to obtain definitive conclusions.
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PMID:Clinicopathological study of chronic hepatitis induced by alcohol with or without hepatitis G virus. 1023 75

Although the hepatitis G virus is unlikely to be a primary hepatotropic virus, its replication sites remain unclear. Using highly strand-specific Tth-based reverse transcriptase PCR we searched for the presence of the viral RNA negative strand in various autopsy tissues in two patients who died of end-stage liver disease. In addition, amplified viral sequences were compared in the 5' untranslated and the putative capsid regions by the single-strand conformation polymorphism (SSCP). Negative strand HGV RNA was detected in bone marrow and spleen from both patients and in lymph node tissue from one. All amplified sequences from a given patient were identical when compared by SSCP and direct sequencing. This lack of difference in the composition of quasispecies recovered from various tissues suggests the presence of a single, common viral compartment in the infected host.
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PMID:Analysis of hepatitis G virus/GB virus C quasispecies and replication sites in human subjects. 1032 81

Excluding acute hepatic failure caused by drugs, the etiology of fulminant hepatitis (FH) remains unknown in many patients. There are conflicting data about a possible pathogenic role for the hepatitis G virus (HGV) in patients with cryptogenic fulminant hepatitis (non-A-E FH). We investigated the presence of circulating HGV in 36 patients with well-documented non-A-E fulminant and 5 patients with subfulminant hepatitis from 3 geographic locations in the United States. Serum HGV RNA was determined by reverse transcriptase-polymerase chain reaction using primers from the NS5 region of the HGV genome. HGV RNA was also measured before and after liver transplantation in 5 patients and at different time points in 7 patients. Serum samples were recoded and reanalyzed for HGV RNA using different primer sets to assess the validity of the HGV RNA assay. HGV was present in serum of 14 of the 36 patients (38.8%) with non-A-E fulminant hepatitis. Twenty percent of patients from the Northeast, 11% of the patients from the Southeast, and 50% from the Mid-Atlantic regions of the United States had circulating HGV RNA. The use of therapeutic blood products was significantly associated with the presence of serum HGV RNA (P <.02). Retesting for HGV RNA with different primers was positive in all but 1 case. HGV RNA is not causally related to non-A-E fulminant hepatitis. The finding of HGV RNA in serum from these patients is likely related to the administration of blood product transfusion after the onset of fulminant hepatitis.
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PMID:The significance of hepatitis G virus in serum of patients with sporadic fulminant and subfulminant hepatitis of unknown etiology. 1043 34

We investigated changes in the titers of positive and negative strands of hepatitis G virus (HGV) RNA and hepatitis C virus (HCV) RNA in serum and liver during and 1 to 3 years after interferon therapy in patients with chronic hepatitis C coinfected with HGV/ GBV-C. Eight (6%) of 134 patients with chronic hepatitis C treated with interferon were positive for HGV RNA and were examined retrospectively. Titers of positive and negative strands of HGV RNA and HCV RNA were determined by strand-specific reverse transcriptase-polymerase chain reaction. Before therapy, HGV RNA titers in liver were lower than those in serum (P = 0.0169), while HCV RNA titers in liver were significantly higher than those in serum (P = 0.0074). No negative strands of HGV RNA were detected in serum, liver, or peripheral blood mononuclear cells in any patients. With interferon therapy, 5 of the 8 patients lost HCV RNA from serum and liver, with sustained normal liver biochemical values and significant histological improvement. HGV RNA disappeared transiently from serum and liver at the end of therapy in 5 patients, but reappeared again after therapy in 4 of them. Two of the 8 patients naturally lost HGV RNA after completion of therapy. These findings suggest that: (1) HGV/GBV-C does not appear to replicate in liver, serum, or peripheral blood mononuclear cells, (2) detection of HGV RNA in liver and peripheral blood mononuclear cells may be a mere reflection of serum HGV RNA, and (3) the long-term clinical outcome of chronic HGV/GBV-C infection appeared to be benign.
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PMID:Long-term follow-up of hepatitis G virus/GB virus C replication in liver during and after interferon therapy in patients coinfected with hepatitis C and G viruses. 1058 92

Thirty-nine patients with chronic liver disease who were being evaluated in a U.S. military treatment facility were tested for antibody to hepatitis C virus (anti-HCV) and for hepatitis G virus (HGV) RNA by reverse transcriptase-polymerase chain reaction. Serum samples from 20 patients (51%) were positive for anti-HCV by immunoblot assay. HGV RNA was found in the sera of only two patients, both of whom were also positive for anti-HCV. HGV appears to have a limited role in causing chronic liver disease in this population of military patients, many of whom had traveled outside the United States. However, HCV infection was commonly associated with chronic hepatitis and cirrhosis, as in civilian patients.
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PMID:Chronic liver disease among U.S. military patients: the role of hepatitis C and G virus infection. 1074 Oct 77

We have analyzed the presence of hepatitis C virus (HCV) and hepatitis G virus (HGV) sequences in bone marrow and serum samples from 48 patients of a hematologic outpatient clinic. HCV RNA was detected in 18 (38%) and 15 (31%) and HGV RNA was detected in 6 (13%) and 9 (19%) of serum and bone marrow samples, respectively. In 3 patients, HGV RNA was detectable in bone marrow but not in the serum; 2 of these patients were negative for the presence of specific antibodies. Using a highly strand-specific Tth-based reverse transcriptase-polymerase chain reaction (RT-PCR), the presence of HCV RNA and HGV RNA negative strand was demonstrated in 4 and 5 bone marrow samples, respectively. Our study shows that HCV and HGV can replicate in bone marrow; in the case of HGV, analysis of serum may underestimate the true prevalence of infection. (Blood. 2000;95:3986-3989)
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PMID:Detection of active hepatitis C virus and hepatitis G virus/GB virus C replication in bone marrow in human subjects. 1084 38

Currently seven viruses, A, B, C, D, E, G and transfusion transmitted virus (TTV), are recognised in the hepatitis virus alphabet. Hepatitis G virus and TTV probably do not cause liver disease in humans. Hepatitis A and E usually cause a self-limiting hepatitis followed by complete recovery but occasionally cause fulminant hepatic failure. Hepatitis B and C are major public health problems worldwide due to their sequelae of chronic hepatitis, cirrhosis and primary liver cancer. Chronic hepatitis C is a particular health issue for Western Europe already, accounting for 40% of end-stage cirrhosis and 30% of liver transplants. The contribution of hepatitis C to chronic liver disease is predicted to rise in the future. Vaccines can prevent hepatitis A and B. Interferon alpha is effective treatment in 25-30% of patients with chronic hepatitis B or C. The prospects for treating chronic hepatitis B have been improved by the introduction of reverse transcriptase inhibitors. Lamivudine is the first drug of this class to be licensed. The optimal use of these new drugs is currently being studied. The success rate for treating chronic hepatitis C can be raised to about 40% with combination therapy of interferon alpha and ribavirin. A large research effort to discover new antiviral agents against hepatitis C is already giving the prospect of more effective therapies in the next few years.
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PMID:Virus hepatitis update. 1119 85

The incidence of GBV-C/hepatitis G virus (GBV-C/HGV) infection after blood transfusion is unknown in Brazil. Many studies have so far addressed its relationship with blood transfusion, but its association with liver disease was not confirmed. A prospective study was carried out between 1996 and 1999 in Rio de Janeiro. Ninety three patients who received blood transfusion during cardiac surgery were followed for six months and blood samples were drawn before and after surgery to determine antibodies to GBV-C/hepatitis G virus (anti-HGenv) using a step sandwich immunoassay and GBV-C/HGV-RNA using reverse transcriptase polymerase chain reaction. The alanine aminotransferase (ALT) levels were serially determined as well as clinical data compiled related to hepatitis. Prior to surgery, anti-HGenv was present in 35.5% (33/93) of patients and 4.3%(4/93) were found to be viremic. Seroconversion following transfusion was observed in 9 patients and 4 additional individuals became viremic for a total incidence of 23% (13/56). Six months after blood transfusion, only 4 of those nine patients previously antibody positive still had anti-HGenv detectable in serum. No patients had clinical or laboratory evidence of acute hepatitis and no correlation was found with GBV-C/HGV infection and number of blood units transfused (p = 0.37). This study highlights the importance of using both HGV-RNA PCR and anti-HGenv to accurately estimate the magnitude of GBV-C/HGV infection. The observed high prevalence and incidence rates show that this infection is common in Brazil; however, no clinical or biochemical evidence of liver disease was demonstrated in the period of study and longer longitudinal observation is needed to define any pathogenic effect.
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PMID:The incidence of GB virus C / hepatitis G virus infection in Brazilian patients who received blood transfusion during cardiac surgery. 1117 63

The diagnosis of hepatitis C infection in the setting of liver transplantation in based on several variables, including histopathologic changes and the presence of viral RNA in the serum. It may be difficult to differentiate acute rejection from recurrent viral hepatitis in liver biopsies from patients who received liver transplants for end-stage hepatitis C infection. The purpose of this study was to analyzed the histologic features, viral load, and in situ viral detection in 37 biopsies taken from 25 people who underwent liver transplant for end-stage hepatitis C infection. Hepatitis C antigen was detected in 9 of 37 (24%) biopsies using immunohistochemistry; the detection rate increased to 19 of 37 (51%) using reverse transcriptase in situ polymerase chain reaction for viral cDNA. Hepatitis E cDNA was detected in 4 of 37 (11%) cases, hepatitis G cDNA in 3 of 37 (8%) cases and in 1 case cytomegalovirus was noted; with several cases of dual infection, 22 of 37 (59%) of tissues were positive for at least 1 virus. Histologic parameters that significantly correlated with in situ viral detection included single-cell hepatocyte necrosis (P = 0.02), bile duct damage (P = 0.03), lymphoid aggregates (P = 0.02), and cholestasis (P = 0.01). Further, a serum viral load exceeding 1,250,000 viral equivalents/ml was strongly correlated with in situ viral detection in the liver (P = 0.01). We conclude that certain histologic features and an increased viral load are highly correlated with the in situ detection of viral RNA in the liver, which is consistent with recurrent viral infection.
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PMID:Correlation of histology, viral load, and in situ viral detection in hepatic biopsies from patients with liver transplants secondary to hepatitis C infection. 1197 67


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