We report an analytical reversed-phase liquid-chromatographic procedure for quantifying nicotine and cotinine in urine, taking into account the presence of interfering caffeine frequently encountered in such specimens. These analytes are extracted from the alkalinized urine with chloroform. After evaporation of the chloroform, the residue is dissolved in methanol and injected into a chromatographic C18 column. Extraction recoveries averaged 80% to 97%. Chromatographic conditions were investigated to obviate caffeine interference. The proposed eluent mobile phase is a polar mixture of water, acetonitrile, methanol, and a pH 4 acetoacetate buffer (65/2/29/4 by vol) adjusted to pH 4.30 +/- 0.02 with triethylamine. High resolution and linearity were obtained for each analyte up to a concentration of 200 mg/L. The minimum detectable amount of each compound was 20 ng per injection, corresponding to 10 micrograms per liter of urine. Correlation with results of gas-liquid chromatography was excellent (r = 0.99). This simple, rapid procedure allows routine screening of tobacco exposure with acceptable precision: within- and between-run coefficients of variation were less than 2% and less than 5%, respectively.

Helicobacter pylori (H. pylori) infection is one of the most common chronic bacterial infections in the world. For the purpose of eradicating H. pylori, quadruple therapies are widely prescribed in patients infected with H. pylori. According to the Maastricht V Consensus Conference, in regions where the rate of resistance of H. pylori to CLR and MTZ is high such as Viet Nam, bismuth quadruple therapy is the first choice. However, bismuth also causes many side efects. The aim of this study was to assess the effectiveness of quadruple therapies on H. pylori infection at Gia Dinh people’s hospital. Seventy-one patients aged 18 years old and older diagnosed with H. pylori infection at the Gastroenterology Unit of Gia Dinh People’s hospital were enrolled in this descriptive cross–sectional study. The efficacy and frequency of side effects of bismuth and non-bismuth quadruple therapies for H. pylori eradication were evaluated and the total rate of H. pylori eradication with both therapies was reported to be 70.4%. The success rate of bismuth quadruple therapy was 80.0%, significantly higher than that of non bismuth quadruple therapy (47.6%). Additionally, the frequency of side effects encountered by bismuth quadruple therapy was insignificantly higher than non-bismuth quadruple therapy (p > 0.05). In conclusion, the effectiveness of treatment with bismuth quadruple therapy was higher than that with non-bismuth quadruple therapy.

Hepatitis B surface Antigen (HBsAg) and hepatitis C antibody (anti-HCV) assays have been performed in most laboratories using a variety of analytical methods with different reagents for Hepatitis B virus (HBV) and Hepatitis C virus (HCV) screening [1][2] . The purpose of this study was to develop an EQA program for dual HBsAg and anti-HCV serological testing to ensure the accuracy and reliability of serological assays. A serum panel of 12 samples containing three negative, three positives for each virus and three positives for both of HBsAg and anti-HCV. These panels were distributed to 102 laboratories in the South of Vietnam. They were required to report their results and any problems encountered on EQA panel. The results show that performance of HBsAg and anti-HCV tests is not only different in terms of method used but also in the types of biological products. Rapid tests (RTs) to detect HBsAg and anti-HCV were most commonly used to screen for HBV and HCV in laboratories. The coincidence rates of RTs for HBsAg and anti-HCV serological assays were 88.24% and 89.86% respectively, while electrochemiluminescence (ECLs) and chemiluminescent immunoassays (CLIAs), Enzymelinked immunosorbent assay (ELISA) showed the best performance for both HBsAg and anti-HCV testing. The most challenging was failed to detect weak positive samples. In conclusion, the differences in test results within and between groups of HBsAg and anti-HCV assay methods indicated a need to improve test conditions at laboratories in Viet Nam.

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