Because cigarette smoking is a definite risk for the development of cardiovascular disease and nicotine induced vasoconstriction may be a possible pathogenetic factor the haemodynamic effects of smoking cigarettes with high or low nicotine content were compared with those induced by chewing nicotine gum in a placebo controlled, crossover study in six healthy volunteers. The three stimuli induced similar increases in heart rate (about 20%) and systolic blood pressure (about 7%) and a decrease in digital blood flow. Although the mean haemodynamic changes parallelled the mean plasma nicotine concentration increases, no correlation was found between them when the individual values were considered. It is concluded that the nicotine induced haemodynamic changes probably occur as a result of the (local) release of vasoactive mediators such as adrenaline or noradrenaline after a threshold plasma nicotine concentration has been reached. Such a threshold may explain the large interindividual variability in susceptibility to smoking induced cardiovascular diseases. blood with a possible decrease of the oxygen supply to the endothelial cell.' In the present study, we compared the haemodynamic response of young healthy smokers to three different nicotine stimuli: a cigarette with high or low nicotine content and a nicotine chewing gum. These three stimuli were compared with a placebo in a crossover study,8 and the induced haemodynamic changes were correlated with increases in the plasma nicotine concentration. Subjects and methods STUDY PROTOCOLSix healthy male smokers (mean(SD) age 30(2.8) years; mean(SD) cigarette consumption 8.2 (1.1) pack year, where 1 pack year corresponds to smoking 1 pack of 20 cigarettes per day during one year) were enrolled in a crossover, placebo controlled study. The trial was carried out according to the Declaration of Helsinki and was approved by the human ethical committee of our institution. The study consisted of 154

The analysis of glucose EQA results collected over a 12-year period showed that professional laboratories obtained better performances than medical offices, and that a general improvement in yearly performance was observed for both types of laboratories.

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Presented here are the results of an external quality control survey organized by the Swiss Center for Quality Control (CSCQ) to evaluate the performance of direct antigen tests (DATs) widely used in Swiss medical practices and laboratories for the diagnosis of group A streptococcal pharyngitis. Twice yearly over a 4-year period, just over 100 participants were requested to analyze positive, weakly positive and negative samples provided to them by the CSCQ with their routinely used DATs and to send the results to the CSCQ. For 1,620 samples distributed, the CSCQ received 1,484 (91.6%) results obtained with 17 different DATs. The specificity of all DATs for negative samples was >91%. For samples containing abundant group A streptococcal antigen, sensitivities ranged from 59.1% to 95.5%; however, for samples containing low levels of antigen, the sensitivity was much lower for all DATs, ranging from 8.7% to 69.8%. Therefore, negative DAT results should be verified with well-performed cultures in order to assure the optimal care of patients with pharyngitis.

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