(DOWNLOAD) "Synthetic Viral Particles Promise to be Valuable in the Standardization of Molecular Diagnostic Assays for Hepatitis C Virus (Editorial)" by Clinical Chemistry ~ Book PDF Kindle ePub Free
eBook details
- Title: Synthetic Viral Particles Promise to be Valuable in the Standardization of Molecular Diagnostic Assays for Hepatitis C Virus (Editorial)
- Author : Clinical Chemistry
- Release Date : January 01, 1999
- Genre: Chemistry,Books,Science & Nature,
- Pages : * pages
- Size : 185 KB
Description
Hepatitis C virus (HCV) is a primarily parenterally transmitted pathogen first discovered in the late 1980s. Infection with HCV is common throughout the world, and disease attributable to this virus is a major public health issue in both developed and developing countries. In the United States alone, ~4 million individuals are infected with HCV, with an estimated 30 000 new infections occurring annually (1). Of those infected by this virus, between 70% and 90% develop chronic HCV infection (compared with only 10-20% of those infected with hepatitis B virus), and 20-30% of chronically infected patients progress to liver disease (liver failure, cirrhosis, and/or hepatocellular carcinoma) within 20-30 years (2). Given these statistics and the lack of an effective vaccine, it is not surprising that the morbidity and mortality attributable to HCV are considerable and on the increase. HCV is responsible for 8000-10 000 deaths per year in the United States, a figure that some experts postulate will triple in the next 10-20 years, and chronic HCV infection is the single most common etiology of hepatic injury in patients undergoing liver transplantation (1). The discovery of HCV in 1989 represents one of the most important accomplishments of molecular biotechnology. An infectious agent that had never been seen or cultured was discovered by cloning fragments of its genome from clinical material; the entire genetic and biochemical composition of the virus was then reconstructed in vitro (3). HCV is a member of the Flaviviridae family of viruses and possesses a single-stranded RNA genome of some 9.5 kb. The RNA sequence contains a single open reading frame and encodes a viral precursor protein of ~3000 amino acids that undergoes posttranslational processing to form six proteins. The HCV genome also contains two untranslated regions, one of 351 nucleotides at the 5' end and a smaller region of just 35 nucleotides at the 3' end. Enzyme immunoassay and immunoblot techniques for detecting anti-HCV antibodies were developed soon after the virus was discovered, and current iterations of these assays enable past exposure to HCV to be determined with a high degree of accuracy. In the United States, universal use of antibody assays to screen blood donors for HCV has been responsible for an 85-90% decrease in the incidence of transfusion-associated hepatitis during the past decade (1). It is perhaps fitting, given the manner in which HCV was discovered, that differentiating active HCV infection from past, resolved infection currently can be achieved only by using molecular assays to detect the presence of viral RNA in peripheral blood. More conventional microbiological approaches for detecting infection, such as culture or antigen detection, have been difficult to develop for HCV and currently play no role in diagnosis. Several molecular techniques, most prominently PCR and branched-chain DNA hybridization, have been used to enable either qualitative or quantitative detection of HCV RNA in serum or plasma (4). In addition, tests have been developed to determine the particular genotype of the HCV population infecting an individual patient. Because therapeutic response rate is influenced by HCV genotype (5), determination of HCV genotype may have prognostic and therapeutic value. Although debate continues among those responsible for the care of HCV-infected individuals regarding optimal use of molecular tests, molecular diagnosis and monitoring of HCV infection are clearly destined to become the standard of care in the relatively near future.
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