Spatiotemporal variations in microcystin concentrations and in the proportions of microcystin-producing cells in several Microcystis aeruginosa populations.

With the aim of explaining the variations in microcystin (MC) concentrations during cyanobacterial blooms, we studied several Microcystis aeruginosa populations blooming in different freshwater ecosystems located in the same geographical area. As assessed by real-time PCR, it appeared that the potentially MC-producing cells (mcyB(+)) were predominant (70 to 100%) in all of these M. aeruginosa populations, with the exception of one population in which non-MC-producing cells always dominated. Apart from the population in the Grangent Reservoir, we found that the proportions of potentially MC-producing and non-MC-producing cells varied little over time, which was consistent with the fact that according to a previous study of the same populations, the intergenic transcribed spacer (ITS) genotype composition did not change (38). In the Grangent Reservoir, the MC-RR variant was the dominant microcystin variant throughout the bloom season, despite changes in the ITS composition and in the proportions of mcyB(+) cells. Finally, the variations in total MC concentrations (0.3 to 15 microg liter(-1)) and in the MC cellular quotas (0.01 to 3.4 pg cell(-1)) were high both between and within sites, and no correlation was found between the MC concentrations and the proportion of mcyB(+) cells. All of these findings demonstrate that very different results can be found for the proportions of potentially MC-producing and non-MC-producing cells and MC concentrations, even in M. aeruginosa populations living in more or less connected ecosystems, demonstrating the importance of the effect of very local environmental conditions on these parameters and also the difficulty of predicting the potential toxicity of Microcystis blooms.

Hepatitis B virus infection on a tropical island: sociodemographic and geographic risk factors in Guadeloupe.

A seroepidemiologic study on a cross-sectional sample of blood donors was carried out in Guadeloupe, a French West Indies island, to estimate the prevalence of hepatitis B virus (HBV) markers, and to investigate the influence of age, socioeconomic, and geographic factors on prior HBV infection. Blood specimens and sociodemographic data were collected in 1989 from 2,339 blood donors residing on the island. A total of 73 (3.1%) of 2,339 were found to be HBV surface antigen carriers, and 518 (22.1%) were positive for antibody to HBV core antigen. Among them, 61 were positive for both markers and consequently 530 persons (22.7%) were considered to have evidence of prior HBV infection. Multivariate logistic regression analyses identified age and low socioprofessional status as being related to HBV infection, as in many endemic areas. In addition, some major geographic risk factors were highlighted, reflecting a strongly hyperendemic situation in specific areas and the potential influence of horizontal transmission or unknown environmental factors on these particular populations.

[Smoking and social class in France 1974-1991]. / Tabagisme et classe sociale en France de 1974 à 1991.

We examined trends in cigarette smoking behaviour in France from 1974 to 1991 separately for men and women as well as according to social class indicators. Overall, cigarette smoking prevalence has declined among men but has increased among women over the 18-year period which was taken into consideration. Analysis by social class groupings shows, among men, that the decrease is greater among higher level executives, professionals and academics and occurred as early as 1983. Among women, there is only a slight and recent downward trend limited to those of higher socio-economic status. These findings are similar to those of other southern European countries, such as Italy or Spain, but are not as yet comparable to what has been observed over the last twenty years in northern Europe, the United Kingdom or the United States of America.

Smoking habits in French adolescents.

A survey on adolescent smoking habits was carried out among 2,587 girls and boys, mostly aged between 11 and 16 and belonging to 16 schools representative of the 'département' of Rhône in France, in order to evaluate present smoking behaviour as well as estimate the influence of parents, friends and sociodemographic factors in acquiring or maintaining the habit. Students were surveyed in schools using a self-administered, anonymous questionnaire. Analysis was carried out using both the univariate and logistic methods, aiming at a precise quantification and description of the smoking habit, as well as an identification of predictors of smoking, separately for girls and boys, and also for triers only, occasional and regular smokers. Smoking regularly increases with age and from the age of 14 becomes slightly more prevalent among girls than boys. The influence of peer smoking (group of friends and best friend) seems stronger than parental smoking, although determinants of smoking differ moderately for girls and boys.

Brain cancer mortality among French farmers: the vineyard pesticide hypothesis.

In this study, the authors assessed the contribution of vineyard pesticides to brain cancer mortality among agricultural workers. A pesticide exposure index (PEI) in vineyards was calculated for 89 French geographical units (départements). The authors estimated standardized mortality ratios among male farmers and farm laborers aged 35-74 y for the years 1984-1986. Poisson regression models, which were fitted to the ecological data, included random effects. Mortality from brain cancer among farmers was significantly higher than mortality for the overall population (standardized mortality ratio = 1.25, p < .001). Univariate analysis revealed a significant link with pesticide exposure in vineyards (relative risk = 1.10; 95% confidence interval = 1.03, 1.18), as did multivariate analysis (relative risk = 1.11; 95% confidence interval = 1.03, 1.19). These results corraborate the evidence that pesticides in vineyards contribute to mortality from brain cancer among farmers.

Case-control study of leukaemia among young people near La Hague nuclear reprocessing plant: the environmental hypothesis revisited.

OBJECTIVE: To investigate the association between childhood leukaemia and established risk factors or other factors related to La Hague nuclear waste reprocessing plant. DESIGN: Case-control study. SETTING: Area within a 35 km radius of La Hague, Normandy, France. SUBJECTS: Twenty seven cases of leukaemia diagnosed during the period 1978-93 in people aged under 25 years and 192 controls matched for sex, age, place of birth, and residence at time of diagnosis. MAIN OUTCOME MEASURES: Antenatal and postnatal exposure to x rays and viral infections, occupational exposure of parents (particularly ionising radiation), living conditions, lifestyle of parents and children. RESULTS: Increased trends were found for use of local beaches by mothers and children (P < or = 0.01); relative risks 2.87 (95% confidence intervals 1.05 to 8.72) and 4.49 (1.52 to 15.23) when categories were aggregated in two levels (more or less than once a month). Consumption of local fish and shellfish also showed an increased trend (P 0.01); relative risk 2.66 (0.91 to 9.51) when categories were grouped in two levels (more or less than once a week). A relative risk of 1.18 a year (1.03 to 1.42) was observed for length of residence in a granite-built house or in a granitic area. No association was shown with occupational radiation exposure in parents. CONCLUSIONS: There is some convincing evidence in childhood leukaemia of a causal role for environmental radiation exposure from recreational activities on beaches. New methods for identifying the environmental pathways, focusing on marine ecosystems, are warranted.

[Neuropsychic effects of cimetidine and ranitidine. Apropos of 1 case]. / Effets neuropsychiques de la cimétidine et de la ranitidine. A propos d'un cas.

The incidence of neuropsychiatric complications is very low in patients receiving conventional doses of cimetidine or ranitidine. In this case report, the same patient presented with psychiatric symptoms successively following treatment with both histamine H2-receptor antagonists, suggesting the involvement of histamine-mediated CNS modulation.

[Current development of smoking in young people in France]. / Evolution récente du tabagisme des jeunes en France.

Two sets of data, collected independently, have been analysed to study the recent evolution of tobacco smoking in France among young people. For the first time a trend towards a reduction of this habit has been observed.

Incidence of leukaemia in young people around the La Hague nuclear waste reprocessing plant: a sensitivity analysis.

The objectives are to investigate the incidence of childhood leukaemia in young people around the French nuclear waste reprocessing plant (La Hague, Normandy) for the period 1978-1992, and to check the sensitivity of the results to the choice of disease clustering tests and reference rates. The performance of three statistical procedures are compared: a conventional approach; a Poisson maximum test, and an extraction mapping technique. On the whole, the results are in general agreement and demonstrate the apparent existence of a distinct cluster of childhood leukaemia, contiguous and south-east of the La Hague nuclear facility.

A case-control study of gastric cancer and nutritional factors in Marseille, France.

A case-control study was conducted in Marseille (France) to investigate the relationship between usual diet and risk of gastric cancer. Patients with histologically confirmed gastric adenocarcinoma were identified in 8 major centres for gastric surgery. Controls were selected in specialized medical centres from patients undergoing functional reeducation for injuries or trauma, according to the age and sex distributions of the cases. The study involved 92 cases and 128 controls who were interviewed with a dietary history questionnaire on their usual diet during the year preceding first symptoms for cases, or preceding interview for controls. Odds ratios for specific foods were calculated after adjustment for age, sex, occupation and energy intake. A reduced risk was observed for consumption of raw vegetables (OR2: 0.55; OR3: 0.41 for the second and third tertiles, respectively), fresh fruit (OR2: 0.63; OR3: 0.50), vegetable oil (OR2: 0.60; OR3: 0.52), pasta and rice (OR2: 1.06; OR3: 0.50) whereas consumption of cakes and pastries (OR2: 1.02; OR3: 2.96), sugar and confectionery (OR2: 0.96; OR3: 1.68) was associated with an increased risk. An increased risk was found for intake of saturated fat (OR2: 1.49; OR3: 1.67), simple sugars (OR2: 1.18; OR3: 1.78) and calcium (OR2: 1.84; OR3: 2.57). A decreased risk was observed with intake of fiber (OR2: 0.49; OR3: 0.59), fibre from vegetables and fruit (OR2: 0.83; OR3: 0.53) and iron (OR2: 0.70; OR3: 0.41).

Nitrosamine, nitrate and nitrite in relation to gastric cancer: a case-control study in Marseille, France.

A case-control study on gastric cancer and diet was conducted in Marseille (France). Ninety-two patients with histologically confirmed adenocarcinoma and 128 controls undergoing functional reeducation for injuries or trauma were interviewed by a trained dietician using a dietary history questionnaire on their usual diet during the year preceding the first symptoms for cases, or preceding interview for controls. Intake of nitrite, nitrate and pre-formed N-nitrosodimethylamine (NDMA) from food was estimated using a food composition table compiled ad hoc. Odds ratios (ORs) were calculated after adjustment for age, sex, occupation and calorie intake. The results indicated that high intake of NDMA was associated with increased risk for gastric cancer. The ORs for the second and third tertile of NDMA intake were: OR2 = 4.13 (95% CI = 0.93 18.27) and OR3 = 7.00 (95% CI = 1.85 to 26.46). Intake of nitrate and nitrite was not associated with increased risk of stomach cancer. Consumption of vegetables was protective in general and independent of their estimated nitrate content.