This work shows that the concentration of ethyl glucuronide (EtG) in hair, a marker for the evaluation of the alcohol consumption, is not influenced by the presence or absence of melanin. The results confirm that, unlike many other substances, the EtG determination in hair has not to take into account the hair colour for the correct interpretation of hair testing results.

phase liquid chromatography (Hwang and others 2002), disclosed another 300 (36) mg/kg of HCN equivalents. Because the sample had been stored and shipped at room temperature in containers that were not tightly closed, it is likely that the original material contained even higher HCN levels and that much of this toxic gas had been lost from the specimen before analysis. The 2 kg or more of toxic feed ingested by each affected cow translates to at least 820 mg of HCN equivalents, approaching the reported lethal dose of 2 mg/kg bodyweight (Radostits and others 1999).The characteristic clinical signs, in conjunction with the consumption of appropriate plant material, are comparable to intoxication due to cyanogenic glycosides. As noted previously (Cran 1985, Roder 2001, Suter 2002, confirmatory HCN detection is a difficult and tedious procedure. Although toxic levels of HCN were detected in the present case, the volatility and rapid breakdown of HCN, combined with the time it normally takes for the samples to be received and analysed, may invariably lead to false-negative results. Therefore, in the search for an alternative approach, the authors took advantage of a more stable metabolite that can easily be monitored. The majority of HCN (80 per cent) is detoxified by the enzyme rhodanese in the liver, producing a thiocyanate metabolite that is excreted mainly through the kidneys with a half-life of up to three days in human beings (Gurnsey and others 1977, Erdman 2004). In the present study, the serum thiocyanate level was determined in blood samples obtained from three surviving cows 24 hours after the initial deaths. The procedure (Lundquist and others 1979) involved an ion exchange clean-up to remove interfering matrix components. After elution with sodium perchlorate, the thiocyanate concentration was determined by a quantitative colorimetric reaction in the presence of sodium hypochlorite and barbituric acid, yielding a derivative with peak absorption at a wavelength of 580 nm. The thiocyanate concentrations in the cows (145, 209 and 211 µmol/l) exceeded the reference range determined for human blood (15 to 70 µmol/l) and reached the same high concentrations as those found in severe cases of cyanide poisonings in human beings (Singh and others 1989). A healthy cow in the neighbourhood had a serum thiocyanate level of 52 µmol/l, suggesting a similar normal range in cattle to that in humans. This view was supported when, one month later, the thiocyanate serum concentration of the three cows was measured again and the values were 50 54, and 60 µmol/l. It was concluded that the conversion of HCN to thiocyanate provides a potentially useful diagnostic marker to confirm suspected exposures to cyanide or cyanogenic glycosides in

The presence of ethanol in human specimens collected during autopsies is generally considered as an indication of recent ante-mortem alcohol consumption. The interpretation of the results may however be impaired by post-mortem formation of ethanol when microorganisms capable of fermentation of glucose to ethanol are present. Since the distribution in the different fluids and tissues remains contentious to conclude on the origin of the detected ethanol, the determination of specific metabolites of ethanol such as ethyl glucuronide (EtG) may be performed to discriminate between exogenous (ante-mortem) and endogenous (post-mortem). Toxicological analysis of specimens from the autopsy of a child aged 14 months displayed a high concentration of ethanol in blood and tissues. In order to discriminate between ante-mortem alcohol administration and post-mortem formation, the presence of microorganisms capable of ethanol production was checked by fermentation tests and the liver was tested for the presence of EtG and compared with a positive control. Fermentation tests displayed in the blood of the deceased the presence of the bacterial strain Lactococcus garvieae capable of producing ethanol from glucose. The absence of EtG in the liver of the deceased compared to the high level (19.56 mug/g) detected in the positive control's liver is a further indication that the ethanol detected in the body of the deceased is of post-mortem origin.

An accurate, selective, and sensitive method for the determination of the nonnucleoside reverse transcriptase inhibitors (NNRTIs) nevirapine (nvp) and efavirenz (efv) in human plasma using gas chromatography-mass spectroscopy in selected ion monitoring mode (GC/MS-SIM) was developed. Solid-phase extraction (SPE) gave extraction yields near 100% for both nvp and efv, and calibration curves were linear over the therapeutic concentration ranges. Variation of intraday and interday precision was below 5%. Intraday and interday inaccuracies varied between 0.6% and 10.4%. The lower limits of detection using a 200-microL plasma sample were 27 ng/mL for nvp and 26 ng/mL for efv, and the lower limits of quantification were 54 ng/mL and 72 ng/mL, respectively. The method was applied to the determination of nvp and efv in plasma specimens of 73 patients in HIV stage III or IV and on antiretroviral treatment in Kigali, Rwanda.