L’électrostimulation surimposée à la contraction musculaire volontaire présente-t-elle un intérêt physiologique chez les sujets âgés ?

OBJECTIVE

To analyze the physiological effects of electrical stimulation with voluntary muscle contraction exercise in postmenopausal women.

MATERIALS AND METHODS

Thirty-two females aged 62 to 75 years were randomly assigned to three groups to perform four activity sessions for six weeks: group ME (N =11) climbed up and down stairs, group ES (N =11) practised electrostimulation, and group ME + ES (N = 10) undertook both activities. Physiological adaptations of body composition (lean and fat masses and bone mineral density), muscular strength (isometric and dynamic), vertical jump and posturokinetic activities (balance and gait) were analysed.

RESULTS

For the three groups, the isometric strength at angle 100 degrees (average increase right and left legs, ME: 19 N.m; ES: 4.5 N.m; ME + ES: 11.5 N.m), the dynamic strength at speed 60 degrees.s(-1) (average increase right and left leg, ME: 15 N.m; ES: 14 N.m; ME+ES: 18.5 N.m) and the vertical jump (ME: 23 mm; ES: 16 mm; ME + ES: 34 mm) increased contrary in the body composition and posturokinetic activities. Nevertheless, the group ME + ES adapted differently on some parameters of bone mineral density (P < 0.05) and dynamic strength (P < 0.01) in relation to the groups ES and ME.

CONCLUSION

Electrostimulation with voluntary muscle contraction exercise could induce different physiologic adaptations compared with electrostimulation or voluntary muscle contraction exercise alone.

Neuromuscular effects of three training methods in ageing women

AIM

The present study aimed to compare the effects of 3 strength development methods on muscular mass and muscular strength in healthy ageing women.

METHODS

Thirty-two healthy women, 62 to 75 years old were randomised into 3 groups. The 3 groups performed 4 sessions a week of strength development for 6 weeks. The 1(st) group (SC) climbed up and down 300 stairs per session. The 2(nd) group (ES) followed an electrostimulation programme on the quadriceps muscles. The 3(rd) group (SC+ES) combined stair climbing with electrostimulation. Before and after the 3 programmes, the muscular mass of the leg was assessed using a biphotonic absorptiometry machine. Isometric (angle 20 degrees and 100 degrees ) and isokinetic (60 degrees /s and 240 degrees /s) knee extension torque was measured using an isokinetic dynamometer.

RESULTS

None of the programmes changed the muscular mass. All 3 groups increased isometric (angle 20 degrees, p<0.001; angle 100 degrees, p<0.003) and isokinetic (60 degrees /s, p<0.0001; 240 degrees /s, p<0.0001) knee extension torque. None of the programmes appeared more efficient than the others for muscular mass or muscular strength.

CONCLUSION

Six weeks of activity (SC, ES or SC+ES) improved the isometric and dynamic muscular strength in ageing healthy women. However, this period was too short to change the muscular mass. None of the activities presented a real advantage over the others in ageing women.

Symptoms and serum precipitins in workers exposed to dry sausage mould: consequences of exposure to sausage mould

OBJECTIVE

Hypersensitivity pneumonitis due to dry sausage mould has been reported in workers who brush off the excess mould which coats dry sausage. Prevalence of symptoms and sensitization to mould among these pork-butchery workers is unknown. The aim of the study was to assess the clinical, radiographic, functional, and immunological features in exposed and non-exposed workers in semi-industrial pork butcheries.

PATIENTS AND METHODS

Symptoms, and serum precipitins against mould extracts, were studied in workers in semi-industrial pork butcheries. Of 600 workers asked to participate, 123 (20.5%) were included. Fifty-nine workers, exposed to dry (raw) sausage mould and Penicillium nalgiovense were compared with 64 non-exposed subjects, for symptoms, chest X-rays, spirometry and CO-transfer measurements. Precipitating antibodies were detected by immunoelectrophoresis and electrosyneresis.

RESULTS

Sneezing, cough, dyspnoea, nasal obstruction, headache, and discomfort were significantly more frequent in the exposed group at work and after work than in the control group (P < 0.05). The prevalence of precipitating antibodies for sausage mould was higher in the exposed group (37%) than in the non-exposed group (9%) (P < 0.01). The mean number of precipitating lines measured by electrosyneresis was higher in exposed workers than in non-exposed workers for mould extract (1.09 vs 0.28, P < 0.05) and for Penicillium nalgiovense (1.77 vs 0.33, P < 0.05). No specific X-ray opacity or lung function impairment was found in either group.

CONCLUSIONS

Clinical symptoms and sensitization to Penicillium nalgiovense are frequent among workers exposed to mould during brushing in dry sausage plants.

High-resolution computed tomography abnormalities in ex-insulators annually exposed to asbestos dust

BACKGROUND

characterize To the effects of high asbestos exposure during annual periods of insulation.

METHOD

170 ex-workers underwent clinical examination, spirometry, standard chest X-rays and high-resolution computed tomography (HRCT). Asbestos exposure was retrospectively assessed for latency, duration, and intensity.

RESULTS

Sixty-six percent of these workers were annually exposed to high concentrations of asbestos dust. Respiratory symptoms were mild. One hundred and nineteen subjects had pleural or pulmonary changes on HRCT, compatible with asbestos exposure. Localized pleural thickening was found in 113 subjects (66.5%); pulmonary nodules or lines in 35 (20.6%). The presence of pleural plaques was linked to intensity of asbestos exposure (P <.01), and length of employment (P <.05). Parenchymal lesions were related to intensity (P <.05) and duration of exposure (P <.05). Lung function of subjects with X-ray changes was not significantly altered.

CONCLUSIONS

Annual asbestos exposure led to a high prevalence of pleural plaques and to mild parenchymal anomalies.

[Cardiovascular risk factors and shift work in men living in Haute-Garonne, France]

OBJECTIVE

The goal of this study was to examine the relationship between shift work and cardiovascular risk factors in a cross sectional survey.

MATERIAL AND METHODS

2 610 men of the PRIME study, aged 50-60 years, residing in Haute-Garonne (France) and selected from health centers and various firms were screened. White-collar workers, retired and disabled men at the time of the study were excluded so the analysis was performed on a sample of 1,341 subjects. Work was categorized as day work (n = 1,161) and three types of shift work: 2 x 8 (n = 108), 3 x 8 (n = 41) and night (n = 31). A comparison of cardiovascular risk factors was performed in the different types of work.

RESULTS

Univariate analysis showed that systolic blood pressure was significantly higher among 2 x 8 workers (132.7 +/- 17.4 mmHg) than in other shift workers and day workers (126.9 +/- 15.1 mmHg). The same difference was observed for diastolic blood pressure. Plasma triglycerides were significantly higher among night workers (1.60 +/- 0.76 g/l) than among day workers (1.29 +/- 0.81 g/L). Logistic regression analysis showed that the risk of hypertension, defined as systolic (> or = 140 mmHg) and diastolic (> or = 90 mmHg) blood pressure and/or antihypertensive drug, was 2 times higher among 2 x 8 shift workers (OR: 2.14, 95% CI [1.42-3.23]) than among day workers after adjustment for BMI, alcohol and tobacco consumption and plasma triglyceride levels. The same result (OR: 1.99, 95% CI [1.28-3.12] was obtained with a different definition of hypertension (systolic > or = 160 mmHg and/or diastolic > or = 95 mmHg blood pressure and/or antihypertensive drug). Among night workers the risk of triglycerides > 2 g/L was higher (OR: 2.52, 95% CI [1.06-6.01] than among day workers. The risk of both hypertension (140/90 mmHg) and hypertriglyceridemia in comparison to day workers was (OR: 2.01, 95% CI [1.33-3.03]) and (OR: 2.44, 95% CI [1.14-5.21]) for 2 x 8 shift workers and night shift workers respectively.

CONCLUSION

The results of this study, putting into evidence a relationship between shift work, hypertension and high level of triglycerides, justify a careful screening by occupational physicians of cardiovascular risk factors among shift workers.

[Development of the occupational carcinogen legislation in the European Community]

The aim of this study is to sum up the development of European Community legislation concerning occupational carcinogens. In terms of prevention, 4 periods were studied. From 1951 to 1972, only a few texts of law were promulgated. From 1972 to 1984, after the ratification of the convention 139 of the International Labour Office, more texts were promulgated. Then, from 1985 to 1992, the protection against occupational carcinogens increased for workers, especially after the specific european directive edicted in 1990. Since 1992, most of the countries in the European Union have included this directive in their legislation. In terms of compensation for occupational cancer, a recommendation of the European Commission stated in 1962 had already proposed a list of compensable diseases. Because of the diversity of compensation means, it is difficult for the European Community to impose a common status.

Distinct signal transduction pathways for activation of rabbit alveolar macrophages in vitro by cotton bract tannin

These experiments were designed to study signal transduction pathways in alveolar macrophages stimulated by condensed tannin or zymosan. Condensed tannins, present in cotton mill dust, alter the host-defense function of alveolar macrophages and may contribute to the pathogenesis of byssinosis. We tried to determine the early steps in signal transduction mechanisms of cell activation by tannin. With the quantification of 51Cr release, we determined that tannin was cytotoxic for the cells after 30 min activation with 130 micrograms for 2 x 10(6) cells. 51Cr release was similar for control cells and zymosan- or 30 micrograms tannin-activated cells. Using the luciferine luciferase reaction, we showed that tannin markedly depleted ATP cell content. In inositol-labeled cells, tannin increased inositolphosphate release in a dose-dependent manner. In lysoPAF-labeled cells, tannin induced synthesis of phosphatidic acid and diglycerides. In the presence of ethanol, the level of tannin-induced phosphatidic acid was slightly reduced, and phosphatidylethanol was synthesized. No phosphatidylethanol was found in alveolar macrophages stimulated by zymosan in the presence of ethanol. GF 109203X, a specific inhibitor of protein kinase C decreased only tannin-induced phosphatidylethanol synthesis. In conclusion, tannin (at 30 or 130 micrograms/ml) activated an inositol phospholipase C in alveolar membranes. Phosphatidylcholine phospholipases C and D were found only at the higher concentration of tannin.