PubMed · 11629758
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O Menner. 1987. [Not Available].. https://pubmed.ncbi.nlm.nih.gov/11629758/
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Opiate use in vivo and in vitro reduces the ability of human peripheral lymphocytes to repair DNA damage caused by both the physical and chemical mutagens that produce single-strand adducts. This decrease in repair leads to increased genetic damage to the individual cell as measured by cytogenetic damage, including sister chromatid exchanges and formation of micronuclei. The expected consequences of this increase in damage can also be established by increases in host cell mutation rate and rate of apoptosis. The effect of this increase in genetic damage can be expected to have significant consequences for HIV-1 or simian immunodeficiency virus infecting those lymphocytes. For example, DNA damaging agents have long been known to induce lentiviral growth and propagation, and this has been found to be true for HIV-1 following ultraviolet light treatment of lymphocytes. However, to date, no one has fully explored the consequences of increased host mutation rate on HIV growth and maintenance. Recent reports have demonstrated the role of viral mutation in such key physiologic processes as resistance to highly active antiretroviral therapy (HAART). Beyond the effects of random mutations in the viral genome, specific mutations in the HIV-1 transcriptase and protease lead to increased accumulation of mutant viruses and the gradual failure of HAART. It therefore remains to be tested whether changes in host cell mutation rate will also predict changes in susceptibility to drug therapy. This also leads to questions about whether the higher rate of viral mutation in HIV-infected drug addicts might be the basis for higher rates of neuroAIDS in this population. It would be attractive to speculate that the increase in the heterogeneity of the virus in addicts produces mutants with a greater capacity to attack neuronal tissue and a high affinity to replicate there.
The aim of this study was to evaluate the performance of a technique for the simultaneous testing of opiates, cocaine and metabolites in hair by interlaboratory comparison. Sixteen forensic and clinical laboratories with different degrees of experience in hair analysis participated voluntarily in the study (no selection criteria were applied). The suggested analytical procedure, the one routinely used in our laboratory, consisted of incubation in HCl 0.1N (45 degrees C, overnight), solid phase extraction (with Bond Elut Certify) cartridges), derivatisation (trimethylsilyl (TMS) derivatives) and GC-MS analysis. Three different mixtures of finely cut (1 mm or less) hair were prepared using drug-users' and drug-free hair: one 'negative' sample (<0.1 ng/mg for morphine, 6-acetylmorphine (6AM), cocaine and benzoylecgonine (BE)), one 'low concentration' sample (between 0.5 and 2 ng/mg) and one 'high concentration' sample (>3 ng/mg). Accuracy and precision (CV% lower than 5.1, 9.9, 5.2, 3.8, 7.3 and 8.3% for morphine, 6AM, codeine, cocaine, BE, and methylecgonine (ME), respectively; range 0.5-5 ng/mg) of the method and homogeneity of the mixtures were evaluated in our laboratory by intraday (CV% lower than 12% for all analytes) and interday analyses (CV% lower than 17% for all analytes except 6AM, 25%). Participants in the study were grouped into: (1) laboratories (n = 6) obtaining the best qualitative and quantitative values, corresponding to those with long experience in hair analysis; (2) laboratories (n = 5) with no reported false positive and/or false negatives; (3) laboratories (n = 5) with one or more reported false positives/false negatives. The results obtained by the labs of the first group were used as reference values. The scatter of data was similar to those obtained in other published studies.
Volatility and thermal stability are necessary physical-chemical properties for analysing a substance by gas chromatography. A derivatization step is required before gas chromatography of benzoylecgonine (the main metabolite of cocaine). In the literature, reactions such as silylation, perfluoroalkylation or alkylation are the most frequently used to derivatize benzoylecgonine. However, they allow the formation of products sensitive to moisture or require a purification step. So, a procedure to derivatize benzoylecgonine with diazomethane before gas chromatographic analysis was evaluated. A study was performed to evaluate the efficiency of conversion of benzoylecgonine in cocaine, the necessary time for reaction and the stability of ethereal solution of diazomethane. The reaction was shown to be very fast in mild conditions and there was no need for a further purification step. When benzoylecgonine was extracted from urine by solid-phase extraction and derivatized with diazomethane, concentrations as low as 25 ng/ml could be detected using GC-MS in the full scan mode.