Incidence of HBV variants with a mutation at nt551 among hepatitis B patients in Nanjing and its neighbourhood.

Aim: To investigate the epidemiology of hepatitis B virus (HBV) strains with a mutation at nt551 in surface gene among hepatitis B patients in Nanjing and its neighbourhood.

Methods: By using mutation-specific polymerase chain reaction (msPCR) established by our laboratory for amplifying HBV DNAs with a mutation at nt551, 117 serum samples taken from hepatitis B patients were detected.

Results: The results showed that 112 samples were positive for nt551A, 4 samples were positive for nt551G.

Induction of SARS-nucleoprotein-specific immune response by use of DNA vaccine.

Induction of effective cytotoxic T lymphocyte (CTL) and/or a specific antibody against conserved viral proteins may be essential to the development of a safe and effective severe acute respiratory syndrome coronavirus (SARS-Cov) vaccine. DNA vaccination represents a new strategy for induction of humoral and cellular immune response. To determine the ability of SARS-Cov nucleoprotein (N protein) to induce antiviral immunity, in this report, we established a stable C2C12 line expressing SARS-Cov N protein, which was used as a target for specific CTL assay.

[A mutation specific polymerase chain reaction for detecting hepatitis B virus genome with A-to-C mutation at nt585].

Objective: To investigate the prevalence of hepatitis B virus (HBV) nt585 A-to-C mutants in China.

Methods: A mutation specific polymerase chain reaction (msPCR) was established for amplifying HBV DNAs with A-to-C mutation at nt585. Two sets of primer pairs with same sequences except for one base at 3' terminus were designed and synthesized according to 48 of the known HBV genome sequences and the popular HBV subtypes, adr and adw, in China.

A mutation specific polymerase chain reaction for detecting hepatitis B virus genome mutations at nt551.

Aim: The hepatitis B surface antigen (HBsAg) is considered to be one of the best markers for the diagnosis of acute and chronic HBV infection. But in some patients, this antigen cannot be detected by routine serological assays despite the presence of virus. One of the most important explanations for the lack of detectable HBsAg is that mutations which occur within the "a" determinant of HBV S gene can alter expression of HBsAg and lead to changes of antigenicity and immunogenicity of HBsAg accordingly.

A novel hepatitis B virus mutant with A-to-G at nt551 in the surface antigen gene.

Aim: Hepatitis B surface antigen (HBsAg) mutant of hepatitis B virus (HBV) is one of the important factors that result in immune escape and cause failure of immunization. In this study we reported and characterized a novel HBV mutant with A-to-G at nt551 and intended to provide theoretical data for prevention of HBV infection in China.

Methods: A methodology comprising polymerase chain reaction (PCR) amplifying, M13 bacteriophage cloning and nucleotide sequencing was used to analyze the sera of the pediatric patient who was hepatitis B (HB) immune failure.

An improved, inexpensive method for the large-scale purification of human nerve growth factor.

Human nerve growth factor (hNGF) was purified to near homogeneity on a large scale from human term placenta with an improved and inexpensive method. The purification procedure included tissue homogenization, ultrafiltration and single CM-cellulose column chromatography. The purified hNGF was a 14.

Expression in Escherichia coli and purification of human thrombopoietin.

Human thrombopoietin (TPO) has been successfully overexpressed in Escherichia coli, with an expression level of about 12% of total cellular protein. The full-length TPO gene was subcloned into the prokaryotic expression vector pKK233-2 under the control of the inducible tac promoter. The recombinant protein was produced mainly in the form of inclusion body.

In vitro development of suramin-resistant clones of Trypanosoma evansi.

By exposure to gradually increasing concentrations of suramin in modified Baltz's cell free culture system, suramin-resistant clones of Trypanosoma evansi, JGcl-160, JX-lcl-160 and ZJcl-140, were derived from suramin-sensitive clones JGcl, JX-lcl and ZJcl, respectively, over a period of 550 days. In vitro tests showed that the IC50 values of JGcl-160, JX-lcl-160 and ZJcl-140 were 358.5, 412.