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hepatitis b virus genotyping

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

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hepatitis b virus genotyping

Postby masrooralam » Mon Jul 11, 2005 6:51 am

hello all.
i m a new member in thsi forum.
i m workig on HBV genotyping but i want to know how to develop HBV GENOTYPES SPEICIFIC PRIMERS. :
kindly guide me in thsi regard.
may u enjoy life.
bye
masrooralam
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Genotype

Postby ginny » Wed Jul 13, 2005 8:56 pm

On the basis of phylogenetic analysis of nucleotide sequences, multiple genotypes and subtypes of hepatitis C virus (HCV) have been identified. Characterization of these genetic groups is likely to facilitate and contribute to the development of an effective vaccine against infection with HCV. Differences among HCV genotypes in geographic distributions have provided investigators with an epidemiologic marker that can be used to trace the source of HCV infection in a given population. HCV genotype 1 may represent a more aggressive strain and one that is less likely to respond to interferon treatment than HCV genotype 2 or 3. However, these observations require confirmation before HCV genotyping can be used in clinical settings.
I would like to become a pediactirc doctor. I also want to get into med-school. I attend UCLA.
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Re: Genotype

Postby masrooralam » Thu Jul 14, 2005 7:34 am

i m working on HBV genotyping not the HCV genotyping dear.also mention how to getbthe orimer sequences
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Ok I think I got your answer ??

Postby ginny » Mon Jul 18, 2005 11:18 pm

Is this what you were looking for??
Specific genotypes of hepatitis B virus (HBV) are increasingly recognized for their clinical significance and association with particular viral mutations. Although many HBV genotyping methods exist, there has been no standardized or commercially available method for direct molecular typing of the HBV genome. A newly available line probe assay (INNO-LiPA HBV Genotyping assay; Innogenetics N.V., Ghent, Belgium) that allows the identification of HBV genotypes A to G was assessed by comparison with pre-S1/pre-S2 sequence analysis of the isolates in 188 serum specimens. All seven genotypes were detected by the line probe assay (LiPA), and complete concordance between LiPA and sequence analysis was observed for 152 specimens (81%). LiPA was able to detect 19 mixed genotype infections not detected by amplicon sequencing, which for the most part were confirmed by cloning and sequencing of the pre-S1/pre-S2 amplicon. Four specimens had discrepant results between the two methods, and five specimens had indeterminate results by LiPA. The HBV DNA in four specimens was unable to be amplified by the nested INNO-LiPA HBV DR amplification primers; however, the HBV DNA in six specimens unable to be genotyped by sequencing was clearly genotyped by LiPA. The INNO-LiPA HBV Genotyping assay appears to be useful for the rapid genotyping of HBV, particularly for the sensitive detection of mixed genotype infections.

It is estimated that more than 350 million individuals worldwide are chronically infected with hepatitis B virus (HBV), of which approximately 20 to 30% risk death from HBV-related liver failure or hepatocellular carcinoma (7, 18). In the past several years, the clinical significance of different HBV genotypes has become increasingly recognized in patients with both acute and chronic HBV infections. For example, genotype C has been more closely associated with a poor prognosis and a more aggressive clinical phenotype (8, 26), while genotype B has been associated with earlier HBeAg seroconversion (2), possibly leading to a lower prevalence of HBV-related cirrhosis. Core promoter and lamivudine resistance mutations were found to be more common in genotypes C and A, while precore stop mutations have been observed more frequently in genotypes B and D (6, 9, 30, 34, 35). Therefore, knowledge of the genotype infecting a patient may assist a physician in making clinical and therapeutic decisions.

Although many HBV genotyping methods exist, there has been no standardized or commercially available method for direct molecular typing of the HBV genome. There are seven genotypes of HBV, based on nucleotide differences of 8% or greater along the entire length of the HBV genome or 4% or greater within the small S gene (HBsAg) (23). Recently, an assay based on the line probe assay (LiPA; INNO-LiPA HBV Genotyping assay, Innogenetics N.V., Ghent, Belgium) was released for research purposes. This method is based on the reverse hybridization principle, such that biotinylated amplicons hybridize to specific oligonucleotide probes that are immobilized as parallel lines on membrane-based strips. The amplified region analyzed overlaps the sequence encoding the major hydrophilic region of HBsAg, which is often investigated as a reliable measure of HBV genetic comparison (11, 19). The present study evaluated the INNO-LiPA HBV Genotyping assay by testing 188 serum specimens positive for HBV DNA that had been genotyped by sequencing and phylogenetic analysis of the pre-S1/pre-S2 region of the HBV genome.

Please e-mail and let know if I helped you this time lol ginny_sonic20032002@yahoo.com
I would like to become a pediactirc doctor. I also want to get into med-school. I attend UCLA.
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