Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Adolescent female mice were inoculated intraperitoneally with coxsackievirus B3 Nancy strain, sacrificed 3 and 5 days later and the livers harvested. A protocol for direct reverse transcriptase in situ PCR (RT-ISPCR) detection of enteroviral RNA in paraffin-embedded liver tissues was developed. The optimal conditions for the assay were determined. The best results were obtained when the tissue was fixed in formalin, prior to being embedded in paraffin, then cut in 5 micron thick sections, and mounted onto silanized slides. After deparaffination the slides were incubated in 1 microgram/m1 Proteinase K for 10 min and cDNA synthesis was carried out. For successful RT-ISPCR 40-50 cycles of amplification were necessary. The optimal concentrations of dNTP, primers and Taq Polymerase for RT-ISPCR were determined by serial dilution assays. Primers were selected from highly conserved sequences in the 5' non-coding region (5'NTR). To detect the viral RNA in the liver, digoxigenin-dUTP was incorporated during amplification, subsequently bound with an antidigoxigenin antibody conjugated to alkaline phosphatase (AP), followed by colorimetric detection with nitroblue tetrazolium salt (NBT) and 5-brom-4chloro-3indolyl-phosphate (BCIP). The result was a blue precipitate in the cytoplasm of hepatocytes from infected mice. Fibroblasts, endothelial cells, lymphocytes and the nuclei of hepatocytes were negative. Thus, RT-ISPCR is a specific method for the detection of enterovirus RNA in the hepatocytes of infected mice, and can be of use for the determination of EV liver disease in man.
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PMID:Direct in situ transcriptase polymerase chain reaction for the detection of Enterovirus genome in liver tissues. 912 62

The genomes of both bacteria and eukaryotic organisms are known to encode selenoproteins, using the UGA codon for seleno-cysteine (SeC), and a complex cotranslational mechanism for SeC incorporation into polypeptide chains, involving RNA stem-loop structures. These common features and similar codon usage strongly suggest that this is an ancient evolutionary development. However, the possibility that some viruses might also encode selenoproteins remained unexplored until recently. Based on an analysis of the genomic structure of the human immunodeficiency virus HIV-1, we demonstrated that several regions overlapping known HIV genes have the potential to encode selenoproteins (Taylor et al. [31], J. Med. Chem. 37, 2637-2654 [1994]). This is provocative in the light of overwhelming evidence of a role for oxidative stress in AIDS pathogenesis, and the fact that a number of viral diseases have been linked to selenium (Se) deficiency, either in humans or by in vitro and animal studies. These include HIV-AIDS, hepatitis B linked to liver disease and cancer, Coxsackie virus B3, Keshan disease, and the mouse mammary tumor virus (MMTV), against which Se is a potent chemoprotective agent. There are also established biochemical mechanisms whereby extreme Se deficiency can induce a proclotting or hemorrhagic effect, suggesting that hemorrhagic fever viruses should also be examined for potential virally encoded selenoproteins. In addition to the RNA stem-loop structures required for SeC insertion at UGA codons, genomic structural features that may be required for selenoprotein synthesis can also include ribosomal frameshift sites and RNA pseudoknots if the potential selenoprotein module overlaps with another gene, which may prove to be the rule rather than the exception in viruses. One such pseudoknot that we predicted in HIV-1 has now been verified experimentally; a similar structure can be demonstrated in precisely the same location in the reverse transcriptase coding region of hepatitis B virus. Significant new findings reported here include the existence of highly distinctive glutathione peroxidase (GSH-Px)-related sequences in Coxsackie B viruses, new theoretical data related to a previously proposed potential selenoprotein gene overlapping the HIV protease coding region, and further evidence in support of a novel frameshift site in the HIV nef gene associated with a well-conserved UGA codon in the 1-reading frame.
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PMID:Genomic structures of viral agents in relation to the biosynthesis of selenoproteins. 915 12

Hepatitis C virus (HCV) has been recognized as the cause of thrombocytopenia occurring in patients with chronic hepatitis C, possibly through autoimmune mechanisms. A patient is described with B cell chronic lymphocytic leukaemia, presenting with a marked leuko-thrombocytopenia and an associated mild haemolysis secondary to HCV infection, in the absence of clinical and biochemical signs of hepatitis. Anti-HCV antibodies were detected in the serum both by ELISA and RIBA but not 2 months before the onset of cytopenia. The presence of HCV RNA was documented both in the peripheral blood mononuclear cells and in the bone marrow by reverse transcriptase polymerase chain reaction of the 5' untranslated region of the viral genome. Of interest, HCV RNA was also found in the serum, showing that viraemia was associated with the presence of circulating anti-HCV antibodies. HCV genotyping, performed by PCR amplification of the core region, revealed the presence of an unclassifiable genotype. The hypothetical mechanisms leading to HCV-induced cytopenia in this patient are briefly discussed. Treatment with corticosteroids was effective in controlling blood cell counts, without increasing viraemia and deterioration of liver disease. HCV infection should be considered in the differential diagnosis of possible causes of cytopenia, mainly in immunosuppressed patients, even in absence of clinical and biochemical signs of hepatitis.
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PMID:Hepatitis C virus-induced leuko-thrombocytopenia and haemolysis. 933 31

Chronic hepatitis C infection (CH-C) accounts for a significant number of patients undergoing orthotopic liver transplantation (OLT). Recently, hepatitis C virus (HCV) genotype-dependent differences in disease outcome and therapeutic responses have been suggested. The objectives of our study were to determine (1) the recurrence of HCV infection after OLT; (2) distribution of HCV genotypes in patients with CH-C who required liver transplantation compared with those who did not; and (3) the 1-year transplantation outcome in patients infected with different hepatitis C genotypes. RNA was extracted from sera of 20 patients who underwent OLT for end-stage liver disease secondary to CH-C (group I) and 52 patients with CH-C who did not require OLT (group II). For viral RNA detection, reverse transcriptase and polymerase chain reaction (RT/PCR) of 5'UT region was performed on all OLT patients both before and after OLT. For genotyping, RT-PCR of the NS 5 region was performed, followed by automated sequencing of the amplification products. Nineteen OLT patients had viral RNA detected by PCR both before and after OLT. One patient had no RNA detected before OLT but became viremic after OLT. The prevalence of HCV genotype 1b was significantly higher in group I patients compared with group II (53% v 23% respectively, P = .01). Examination of outcome at 1 year after OLT showed that 9 of 10 patients with HCV genotype 1b had histological evidence of hepatitis compared with 4 of 9 patients with other genotypes (non-1b) (P = .06). However, the number of patients who had one or more episodes of rejection, underwent retransplantation, or died at 1 year after OLT were similar. Recurrence of HCV infection after OLT was shown in all studied patients. Hepatitis C genotype 1b is more prevalent in our patients who underwent transplantation compared with a group with chronic hepatitis C who did not require transplantation (P = .01). Patients infected with HCV genotype 1b may have a higher risk of histological hepatitis after transplantation.
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PMID:Hepatitis C genotypes in liver transplant recipients: distribution and 1-year follow-up. 934 11

The Fas receptor (APO-1/CD95) is expressed on hepatocytes and is thought to be important in triggering apoptosis after ligation by the Fas ligand carried on cytotoxic T cells. Recent evidence has shown that several splice variants of Fas exist, the major one of which (FasTMDel) may produce a soluble protein which can modulate apoptosis by interacting with ligand. There are no data on the expression of splice variants of Fas in liver disease. RNA was extracted from needle biopsies from 13 patients with hepatitis C virus (HCV) infection and six normal liver samples. By reverse transcriptase polymerase chain reaction (RT-PCR) FasTMDel expression was demonstrated at the mRNA level, in both normal and HCV-infected liver. Quantitative PCR demonstrated an increase in Fas transcript relative to FasTMDel in HCV infection. This difference is due to an induction of Fas, with FasTMDel remaining at constant levels in the two groups. If translated into protein, liver cells may express more Fas and thus be susceptible to apoptosis inducible by ligand-bearing cytotoxic T cells. These findings suggest that mechanisms exist to regulate the differential splicing of Fas and FasTMDel dependent on the cell's environment. The degree of alteration in the levels of Fas relative to FasTMDel occurred independently of the ALT levels and histological grading of the HCV-infected cases. However, an association was noted between increasing Fas:FasTMDel ratio and log viral load in the liver, measured by competitive PCR.
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PMID:Alteration in mRNA levels of Fas splice variants in hepatitis C-infected liver. 942 85

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are known to be associated with hepatocellular carcinoma (HCC). In this study, we investigated the prevalence of the newly described hepatitis G virus (HGV) in patients with HCC. The sera of 85 patients (66 male, 19 female, 61 +/- 11 years) with HCC were studied for the presence of HGV RNA by reverse transcriptase-polymerase chain reaction. Seventeen (20%) of 85 patients with HCC, 10 (16%) of 61 patients with chronic hepatitis B without HCC and 14 (20%) of 68 patients with chronic hepatitis C without HCC were infected with HGV, a significantly higher proportion when compared with two (2%) of 85 healthy controls (P < 0.01). When grouped according to the underlying cause of liver disease, HCC patients with HBV infection (33%), HCV infection (21%), alcoholic liver disease (17%), or cryptogenic cirrhosis (15%) had similar serum levels of HGV RNA. Four of the 17 (24%) HGV-positive patients with HCC were coinfected with HBV and six (35%) with HCV; thus, 59% of HGV-positive patients with HCC were coinfected with other hepatotropic viruses. Seven (41%) HGV-positive patients were infected with HGV only. Patients with HGV infection were more likely to have a history of blood transfusion than patients without HGV infection (P = 0.024). Hence, the prevalence of HGV is significantly higher in patients with HCC in comparison with the healthy population.
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PMID:Prevalence of hepatitis G virus in patients with hepatocellular carcinoma. 943 Mar 61

Increasing evidence suggests that the hepatitis C virus (HCV) might be involved in the pathogenesis of B cell non-Hodgkin's lymphomas (NHL). Since several HCV genotypes are currently identifiable and might be involved in the pathogenesis of different diseases (with different severity and responsiveness to therapy), the aim of our study was to assess the prevalence of viral genotypes in a group of patients with HCV-related NHL. Among 470 consecutive patients, 42 HCV Ab-positive cases were identified. HCV RNA could be detected by reverse transcriptase-polymerase chain reaction and genotyping performed in 31 of these cases. As compared to our control group (211 healthy blood donors and patients with chronic liver disease), a striking high prevalence of genotype 2ac was detected among B cell NHL (48.4 vs 9.0%), with a relative risk of infection of 5.37 (P < 0.0001). No major differences were observed in the distribution of NHL histotypes and in the clinical features among patients with genotype 1b (the other most frequent genotype) or 2ac, a part from a trend towards a higher percentage of liver disease and a lower likelihood of response to interferon for patients with genotype 1b. The same high prevalence of genotype 2ac has been recently reported in patients with mixed cryoglobulinemia (MC), monoclonal gammopathies, B cell NHL complicating MC and autoimmune hepatitis. All these data taken together suggest that genotype 2ac might be involved in the pathogenesis of lymphoproliferative and autoimmune disorders.
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PMID:The genotype of the hepatitis C virus in patients with HCV-related B cell non-Hodgkin's lymphoma. 944 35

The aim of this study was to determine the prevalence of infection with the newly described hepatitis G virus (HGV) in a liver transplant cohort, and to establish the frequency and nature of hepatitis in those with and without HGV infection. A reverse transcriptase-polymerase chain reaction technique was employed to determine viraemia in the patients, and liver biopsies taken at different times after transplantation were assessed histologically. Hepatitis G virus RNA was detected in 47% of the liver transplant recipients investigated. Those positive for HGV had received significantly more blood or blood products than the HGV-negative patients. The frequency of abnormal liver function tests was similar in HGV-positive and HGV-negative recipients. Bile duct epithelial cell damage was more frequently seen in those with HGV viraemia. This study indicates that almost half of the liver transplant recipients in Northern England are positive for HGV, and that infection is associated with exposure to blood and blood products. It appears that, in the immunosuppressed patient, HGV does not cause clinically significant liver disease, at least up to 2 years after transplantation. If HGV infection is associated with hepatitis outside this clinical setting, it is likely that the liver damage is immunopathologically mediated rather than as a result of direct viral cytotoxicity.
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PMID:Hepatitis G virus does not cause significant liver disease after liver transplantation. 949 15

The development of policies to prevent nosocomial transmission of hepatitis C virus (HCV) infection in hemodialysis units is critically dependent on the understanding of the relationship between tests for anti-HCV, HCV RNA, and HCV genotype and the patients' clinical characteristics. We tested sera from all patients on the renal transplant waiting list at the New England Organ Bank between November 1986 and June 1990 for anti-HCV by a third-generation enzyme-linked immunosorbent assay (ELISA3) and a third-generation recombinant immunoblot assay (RIBA3). All ELISA3-positive sera were tested for HCV RNA by reverse transcriptase "nested" polymerase chain reaction, and the genotype was characterized by restriction fragment length polymorphism. Sera were available in 1,544 of 3,243 (48%) patients on the waiting list, of whom 287 (19%) tested positive for anti-HCV by ELISA3. Two hundred eighty-six randomly selected, anti-HCV-negative patients served as controls. Compared with anti-HCV-negative controls, anti-HCV-positive patients had a longer duration since initiation of renal replacement therapy, higher number of previous kidney transplants and blood transfusions, higher proportion of patients with anti-HBc, history of liver disease, history of non-A, non-B hepatitis, and elevated serum alanine aminotransferase, and lower serum albumin concentrations. Of the 287 anti-HCV-positive sera, 261 (91%) were reactive by RIBA3, 21 (7%) were indeterminate, and five (2%) were nonreactive. HCV RNA was detected in 224 of 275 (81%) ELISA3-positive patients, in whom additional sera were available. There were no significant differences in clinical or laboratory characteristics between ELISA3-positive patients with and without HCV RNA. Genotypes 1a, 1b, 2a, 2b, 3a, and 4 were present in 53%, 23%, 8%, 10%, 4%, and 2% of patients, respectively. Infection with one, two, or three different HCV genotypes was present in 92%, 7%, and 1%, respectively. There was no significant association between the type or number of HCV genotypes and RIBA3 reactivity. There were no major differences in clinical or laboratory characteristics between genotypes or between single and mixed infection. In summary, this study provides detailed information regarding the relationship between tests for anti-HCV, HCV RNA, and HCV genotypes and the clinical and laboratory characteristics of a large, well-characterized cohort of patients referred for renal transplant.
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PMID:Serologic and virologic profiles of hepatitis C infection in renal transplant candidates. New England Organ Bank Hepatitis C Study Group. 963 34

Hepatitis G virus (HGV) is a flavivirus that can cause acute hepatitis and persistent infection but its role in chronic liver disease or primary liver cancer is unproven. In this study we have examined the prevalence of HGV RNA in the serum of patients with hepatitis C virus (HCV) infection and in patients with cryptogenic chronic liver disease, including non-alcoholic steatohepatitis (NASH), and in patients with HCV-related hepatocellular carcinoma (HCC) and HCC arising in patients with cryptogenic liver disease. One-hundred and thirty patients who were positive for antibody to HCV (anti-HCV), 54 patients with cryptogenic chronic liver disease (including 17 patients with NASH) and 46 patients with hepatitis C-related (n = 27) or cryptogenic liver disease-related HCC (n = 19) were studied. HGV RNA was detected using nested reverse transcriptase-polymerase chain reaction (RT-PCR) and was found in 16.1% of patients with HCV infection. HGV RNA was not detected in any patient with cryptogenic liver disease. In patients with HCC, 7/34 samples were positive for HGV RNA and six out of seven HGV-positive subjects also had HCV infection. Only one patient with HCC in cryptogenic liver disease was positive for HGV RNA. Hence, cryptogenic liver disease in the UK is not caused by HGV/GBVc infection. It seems unlikely that HGV plays a significant role in hepatocarcinogenesis.
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PMID:Hepatitis G infection: role in cryptogenic chronic liver disease and primary liver cell cancer in the UK. Trent Hepatitis C virus Study Group. 965 69


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