Volatile nitriles are present in cigarette smoke. We tested the hypothesis that the presence of any of four nitriles in the blood can serve as a marker of recent cigarette smoking. We determined the sensitivity and specificity of these nitriles as indicators of daily cigarette smoking in 24 smokers (Group A) and 18 non-smokers (Group B), as well as the correlation between intensity of daily smoking and the blood concentration of acetonitrile. A new head space GLC assay method was used. Of the four nitriles, only acetonitrile was present in the blood of any study subject. Acetonitrile was moderately sensitive (67%) and entirely specific (100%) for self-reported daily smoking. There was fair correlation between blood acetonitrile concentration and the average daily number of cigarettes smoked (r2=0.39; P=0.001), and the mean blood acetonitrile concentration was significantly higher (P=0.03) among subjects with higher ( > 10 cigarettes per day) current cigarette exposure (148.3 ± 18.0 ?g/l) than among smokers with low or minimal (1-10 cigarettes per day) exposure (43.3 ± 6.0 ?g/l). Thus, acetonitrile in blood appears to be highly specific and a moderately sensitive marker of cigarette smoking with a dose-effect relationship. As such, acetonitrile shows promise as a marker of current cigarette exposure.

Ce travail a pour objet de présenter une nouvelle méthode de dénombrement des Salmonella dans différents types d'eaux (de rivière, saumâtre, eaux usées brutes et épurées) basée sur l'utilisation d'un milieu d'enrichissement au sélénite additionné de Novobiocine et de Pril et sur une adaptation de la technique du N.P.P. à l'ensemencement d'échantillons de grands volumes après filtration permettant de quantifier les très faibles concentrations de Salmonella. Les vérifications des performances de cette méthode d'isolement et de quantification sont basées sur l'étude des croissances de différentes souches de Salmonella et d'autres espèces bactériennes dans le milieu d'enrichissement modifié, ainsi que sur les résultats quantitatifs et qualitatifs fournis par cette méthode lorsqu'elle est appliquée à des échantillons d'eau en provenance de l'environnement aquatique. Ces résultats montrent notamment que la méthode proposée est suffisamment sensible pour détecter 1 à 2 Salmonella dans 10 litres d'eau analysée et qu'elle ne parait pas exclure de sérotypes, du moins parmi ceux les plus fréquemment isolés en France. L'efficacité de la méthode standardisée API Z pour l'identification enzymatique du genre Salmonella a été également testée en référence aux résultats de la sérotypie.This paper presents a new method for enumerating Salmonellae in environmental waters (freshwater, brackishwater, sewage and treated waters) using the F Selenite enrichment broth modified by the addition of Novobiocin and Pril, and an adaptation of the M.P.N. method for the inoculation of large amounts of water after filtration to improve the enumeration of low concentrations of Salmonellae. The verification of the performance of this detection and enumeration method are based on the study of the growth of different Salmonellae species and of others bacterial species in the modified enrichment broth, and on the quantitative and qualitative results obtained by the application of this methodology to aquatic environmental samples. These results show on one hand, that the sensitivity of the proposed method allows to enumerate 1 to 2 Salmonellae in 10 liter samples, and on the other hand that this method to net exclude any serovar from those which are the most frequently isolated in France. The efficiency of the API Z standardized method for the Salmonellae enzymatic identification versus serological identification was also verified