Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hepatitis C virus (HCV) is a small enveloped RNA virus belonging to the family flaviviridae and genus hepacivirus. The HCV RNA genome is 9,600 nucleotides in length and encodes a single polyprotein that is post-translationally cleaved into 10 polypeptides including t3 structural (C, E1, and E2) and multiple nonstructural proteins ([NS] NS2 to NS5). The NS proteins include enzymes necessary for protein processing (proteases) and viral replication (RNA polymerase). The virus replicates at a high rate in the liver and has marked sequence heterogeneity. There are 6 genotypes and more than 90 subtypes of HCV, the most common in the United States being 1a and 1b (approximately 75%), 2a and 2b (approximately 15%), and 3 (approximately 7%). Acute hepatitis C is marked by appearance of HCV RNA in serum within 1 to 2 weeks of exposure followed by serum alanine aminotransferase (ALT) elevations, and then symptoms and jaundice. Antibody to HCV (anti-HCV) tends to arise late. In acute resolving hepatitis, HCV RNA is cleared and serum ALT levels fall to normal. However, 55% to 85% of patients do not clear virus, but develop chronic hepatitis C. Chronic hepatitis C is often asymptomatic, but is usually associated with persistent or fluctuating elevations in ALT levels. The chronic sequelae of hepatitis C include progressive hepatic fibrosis, cirrhosis, and hepatocellular carcinoma. Extra-hepatic manifestations include sicca syndrome, cryoglobulinemia, glomerulonephritis, and porphyria cutanea tarda. Knowledge of the course and outcome of hepatitis C is important in developing approaches to management and therapy.
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PMID:Course and outcome of hepatitis C. 1240 73

Essential mixed cryoglobulinemia (type II) has turned out to be secondary to hepatitis C virus (HCV) infection in the large majority of patients. Interferon might be anticipated to be effective only in HCV-associated cryoglobulinemias. We found that interferon was highly effective in an HCV-positive patient with true essential type II mixed cryoglobulinemia. The patient presented with symptomatic cryoglobulinemic vasculitis without underlying immunologic, infectious, or neoplastic diseases. Tests for HCV viremia, a reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay, and anti-HCV antibodies (third-generation assays) were positive before therapy. The patient had severe cryoglobulinemic vasculitis with purpura, peripheral neuropathy, and membranous proliferative glomerulonephritis. The cryocrit before therapy was 6 percent in the patient. Recombinant interferon alfa-2a (Roferon-A, Hoffmann-LaRoche, Basel, Switzerland) was administered at a dose of 3 million units per day for three months and 3 million units every other day for the subsequent nine months, a protocol adopted for HCV-associated cryoglobulinemia. The patient had a complete clinical response, with the disappearance of serum cryoglobulins and all signs of cutaneous vasculitis and with the normalization of kidney-function results and urinary values in the patient with nephropathy. The patient has remained in complete remission for more than one year since the withdrawal of therapy. True essential mixed cryoglobulinemia with HCV infection complicated with glomerulonephritis represents a therapeutic challenge.
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PMID:Hepatitis C virus-associated type II mixed cryoglobulinemia vasculitis complicated with membranous proliferative glomerulonephritis. 1921 13