Abstract

      Background and objective: Hepatitis B virus (HBV) is a DNA virus with high tendency toward hepatic tissue. There are currently about 3 million HBV-infected people and 350 to 400 million chronic carriers of this virus in the world. X protein plays a role in the over-expression of oncogenes, carcinogenicity of liver cells and overlaps with the basal core promoter of the virus. Mutations at specific nucleotides of this region increase viral replication and liver disease progression. The aim of this study was to investigate the frequency of mutations at nucleotides 1762, 1764 and 1766 of HBV X gene in patients with chronic hepatitis B and hepatitis B-related cirrhosis.

      Methods: In this study, 102 patients including 68 chronic hepatitis patients and 34 patients with hepatitis B-related cirrhosis were enrolled. After DNA extraction, HBV X gene was amplified and sequenced using Semi Nested-PCR. Obtained gene sequences were compared with the standard sequence of HBV virus X gene available in the gene bank (Okamoto AB033559). Then, the mutations in the gene X of HBV were identified.

      Results: Comparison of the standard sequence with sequences obtained from patients showed the presence of A1762T / G1764A mutation in 12 chronic (17.64%) and 13 cirrhotic (38.23%) patients. Also, C1766G / G1764T mutations were found in 8.23% of chronic patients and 17.64% of cirrhotic patients.

      Conclusion: A1762T / G1764A mutations in the overlapping region of the basal core promoter with gene X C-terminal may lead to liver disease progression from chronic hepatitis to cirrhosis, by changing the amino acid sequence of the X protein.

ABSTRACT

       Background and Objective: Prostate specific antigen (PSA) is considered as one of the most reliable biomarkers of cancer and other known prostate diseases. In the present study, solid phase sandwich immunoradiometric assay was used to measure the amount of PSA. In this type of measurement, a pair of anti-PSA antibodies on the solid phase and labeled with Iodine-125, participate in forming a complex with two different epitopes of PSA.

       Methods: Variables such as irradiation level, modification of polymer surfaces by alcohol washing, different concentrations and volumes of antibody, incubation temperature and drying conditions that influence the direct coating process were optimized. Finally, the stability, accuracy and precision of the laboratory kit were evaluated by comparison with a foreign kit.

      Results: According to the obtained results, preliminary preparations such as irradiation, tube washing and specific temperature conditions are not required during the coating process. Drying by lyophilization method does not affect the quality of coating. Antibody concentration of 2.5 μg/ml and coating volume of 800 μl were determined as the optimum conditions for coating, which had good stability within a year. Alignment of results obtained from the domestic and foreign kits for accuracy of 30 samples from patients was confirmed by T-test (sig 2-tailed= 0.993 and 95% confidence interval). The short-term and long-term precision for three control ranges (low, medium, high) were less than 0.25 and 0.33 of allowable total error (TEa = 10%), respectively.

       Conclusion: The produced domestic kit has acceptable precision according to the CLIA criteria.

       Keywords: Biological testing, Radioimmunometric assay, monoclonal antibody, prostate specific antigen, prostate disease.