S-(+)-Methamphetamine is frequently found as the only isomer in urine specimens from methamphetamine abuseres. Enantiomerically pure S-(+)-methamphetamine can be synthesized from ephedrine or pseudoephedrine via chloroephedrine intermediates. These intermediates are unstable and capable of cyclizing to form cis- and trans-1,2-dimethyl-3-phenyl aziridine. Studies were done to determine if these intermediates could be detected when using a common gas chromatographic-mass spectrometric analytical method (derivatization with heptafluorobutyric anhydride, HFBA) for toxicological screening of methamphetamine. Analysis of (+)- or (-)-chloroephedrine after extraction into hexane and derivatization with HFBA indicated that both pseudoephedrine and ephedrine were the major compounds detected. Direct derivatization of a hexane solution of cis-1,2-dimethyl-3-phenyl aziridine yielded only the derivatives of ephedrine and pseudoephedrine, indicating that the aziridine intermediate is responsible for the formation of the ephedrine or pseudoephedrine. These studies indicate that the aziridine intermediates would not be detected in methamphetamine samples following HFBA derivatization.

Some structural analogues of amphetamine are now important drugs of abuse in Thailand. The utility of the Roche Abuscreen ONLINE reagent amphetamine immunoassay test kit to detect these analogues was studied. The test showed high cross-reactivity to 3,4-methylenedioxyamphetamine (MDA), but low cross-reactivity to its parent drugs, 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA), as well as to methamphetamine and ethylamphetamine. Also observed in this study was a methamphetamine detection sensitivity enhancement effect of amphetamine, which is the active metabolite of methamphetamine. Correlation between the measured concentration values and the actual amount of these two drugs in the sample was, however, low. Thus, the test can be used to detect methamphetamine only when amphetamine is also present in the sample resulting from either co-administration or metabolism of methamphetamine.

ABSTRACT:In this study, drinking water from various sources in Bangkok and two other provinces in Thailand was collected, and its physical properties and mineral content were determined. Water from canals and dug wells contained diverse components making it turbid and coloured. Artesian water from the same province as canal and dug well water had similar mineral content, indicating that pollutants could spread thoroughly. The amount of iron detected in tap water varied from house to house, depending on its plumbing system since it came from corroded aged metal pipelines. The purity and mineral content of some bottled purified and mineral water were identical to that of the tap water. Furthermore, there was phosphate contamination in bottled water, probably from the bottle washing powder. Both local and imported bottled mineral water contained lower amounts of calcium and magnesium than expected, thus they might not be an effective mineral supplement. The high sodium content of sports drinks could make them harmful to health. The perception that bottled water is healthier than tap water should be reconsidered.

BackgroundSince measured low density lipoprotein-cholesterol (LDL-C) has been available in clinical laboratories, there have been concern about the disagreement between measured and calculated LDL-C and the factors causing their disagreement.Material/MethodsSerum lipid concentrations were collected from 1,339 medical records of patients admitted to hospital between 2013 and 2015. They were grouped by their total cholesterol (TC), triglycerides (TG), and high-density lipoprotein-cholesterol (HDL-C) concentrations and the agreement between measured and calculated LDL-C was statistically analyzed.ResultsA strong relationship was found between measured and calculated LDL-C. Significantly disagreements between measured and calculated LDL-C were found in all groups in 2013 and 2014 when lipids were analyzed by Cobas C501. Disagreements found in groups of low TG and low HDL-C concentrations in 2015 were when lipids were analyzed by Abbott Architect ci8200. In groups of calculated LDL-C <1.81 mmol/L, around 80% had the measured LDL-C >1.81 mmol/L. Among various atherogenic indices, non-HDL-C showed the strongest relationship with LDL-C, while TC to HDL-C ratio showed the strongest agreement with the LDL-C.ConclusionsThe disagreement between measured and calculated LDL-C in a clinical laboratory seemed to depend on the analytical system used, and was probably associated with individual laboratory variations.

BackgroundThis study aimed to evaluate how the tests for blood glucose (BG) and diabetic complications have been utilized in a hospital in Thailand.Material/MethodsPatient medical records having the results of BG, HbA1c, and/or urine microalbumin presented and the records of DM patients having the results of serum lipids, serum LDL-C, and/or serum creatinine presented were selected. The data of diagnosis, ordered tests, and testing results in these records were extracted for evaluation.ResultsThis study recruited 1066 patients diagnosed with DM and 3081 patients diagnosed with other diseases. Point-of-care testing (POCT) for BG was repeatedly used in 371 non-DM cases; most of its results were normal. The results of BG and HbA1c were often used together. There was a good relationship between them, and these test results indicated poor glycemic control in 58% of DM cases. In non-DM cases, the test results agreed, indicating normoglycemia in 17.32%, pre-diabetes in 20.47%, and diabetes in 21.78%. To prevent diabetic nephropathy, serum creatinine was frequently used, whereas urine microalbumin, the recommended test, was underutilized. The result of LDL-C from both direct measurement and calculation were used; however, based on the same guidelines, the results of measured LDL-C indicated risk of cardiovascular diseases in a higher percentage of DM cases than did the results of calculated LDL-C.ConclusionsThe use of POCT for BG in hospitalized patients may be inappropriate. The utilization of urine microalbumin should be promoted to effectively prevent diabetic nephropathy.