Clinical Profile, Genotype and Management Updates of Hepatitis B Virus

Abstract

Hepatitis B virus (HBV) is a well known agent of acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Around 400 million people worldwide carrier of HBV of which more than 250 million reside in Asia, and 1-2 million people have died from it. It has a partially double-stranded DNA, having 3.2-kb genome size and replicate via reverse transcription of RNA intermediate. In the natural history or during the antiviral therapy of chronic HBV infection, seroconversion from HBeAg to anti-HBeAg is usually accompanied by a decrease in viral replication and remission of liver disease. Based on genomic sequence data HBV is classified into eight genotypes A-H and four major serotypes ayw, ayr, adw and adr on the basis of complete genome and S gene sequence analysis. Genotypes and serotypes are useful tools in understanding the epidemiology of HBV infection. HBV genotypes have distinct geographical distributions. The HBV variants appear during HBeAg seroconversion and they bring mutations in the precore region (PC) that prevent HBeAg synthesis. Another common HBeAg variant is the basal core promoter mutant (BCP) characterized by point mutation in the promoter of both HBeAg mRNA and core protein mRNA. The most frequent core promoter mutation is the double A1762T and G1764A nucleotide exchange, which results in a substantial decrease in HBeAg expression but enhanced viral genome replication. The approved antiviral drugs such as Interferon, lamivudine, adefovir dipivoxil, entecavir and telbivudine for purpose of treating chronic HBV infection is to prevent or stop the progression of liver injury by suppressing viral replication or eliminating infection. Sustained losses of viral markers of active viral replication (HBeAg and HBV DNA) are the standard end point of the therapies.

Comparison of adefovir dipivoxil and pegylated interferon alpha-2a treatment in chronic hepatitis B patients

“…Adefovir, is a prodrug of ADV. Adefovir is a acyclic nucleotide analogue of adenosine diphosphate [7]. Adefovir is phosporylated to its active metabolite adenosine diphosphate by cellular kinases.…”

Production and characterization of166Ho polylactic acid microspheres

“…There are various approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion; and suchlike approach is utilizing microspheres as carriers for drugs. 6,7 A promising local radionuclide therapy employs radioactive microspheres. Two 90 Y microspheres products are currently commercially available in clinical use: glass-based TheraSpheres and resin-based microspheres.…”

“…Two 90 Y microspheres products are currently commercially available in clinical use: glass-based TheraSpheres and resin-based microspheres. [5][6][7][8][9] The selection criteria for radionuclide therapy using radioactive microspheres have to include the physical and chemical characteristics of radionuclides and microspheres. The ideal properties for radiolabeled microspheres or particles for radionuclide therapy include high mechanical stability to resist breakdown; high chemical stability to resist elution of radioactive label, macrophage removal, or radiolysis; uniform size; unit density to prevent settling or streaming; relative ease of labeling and radionuclide label with high-energy beta particle; low photofraction; and intermediate (days) half-life.…”

“…The ideal properties for radiolabeled microspheres or particles for radionuclide therapy include high mechanical stability to resist breakdown; high chemical stability to resist elution of radioactive label, macrophage removal, or radiolysis; uniform size; unit density to prevent settling or streaming; relative ease of labeling and radionuclide label with high-energy beta particle; low photofraction; and intermediate (days) half-life. 3,[7][8][9] Early studies used angular fragments that were made by crushing the bulk material and sieving the particles to grade in the desired diameter. 9 The first plastic microspheres were labeled with 90 Y and showed an unpredictable and catastrophic leaching of yttrium, which brought them into question.…”

“…8,11 Polylactic acid has been recently chosen as a matrix of microparticles, incorporating either (before their preparation) the neutronactivatable 165 Ho complexes or metallic rhenium-185 to rhenium-187 or being labeled (after their preparation) by the radioactive yttrium-90 or a rhenium-188 salt for intra-arterial therapy. [7][8][9][10][11][12] In addition to microspheres, the type of radionuclide plays a significant role in the success of the therapeutic strategy. Yttrium-90, rhenium-188, and holmium-166 radioisotopes have unique characteristics, which make them potentially suitable for the radionuclide therapy.…”