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Biomedical subjects

B Nemery

Publications and source records attributed to B Nemery.

138 records · Page 8Linked to original sources
PubMed1981

Significance of small airway tests in middle-aged smokers.

In 54 asymptomatic lifelong nonsmokers and 105 current smokers, all steelworkers 45 to 55 yr of age, we measured several lung function indexes in order to assess the significance of small airway tests, slope of phase III of the N2 single-breath washout (delta N2), and bolus closing volume and closing capacity (CC/TLC). Smokers had all mean indexes significantly different from nonsmokers, with CC/TLC and delta N2 being the most frequently impaired tests. Smokers with small airway disease (abnormal CC/TLC or delta N2) but normal forced expiratory volume in one second (FEV1) vital capacity had a significantly lower FEV1/height3 (p less than 0.001) than subjects without small airway disease. The latter had indexes similar to nonsmokers. Our data suggested that smokers with small airway disease experience a more rapid decline in their FEV1 and thus are more susceptible to long-term smoking than smokers without small airway disease. The later appear to be resistant to tobacco-induced chronic airflow obstruction.

Aging↗
PubMed1981

[Study of lung symptomatology and lung function in steelworkers].

We have examined 272 steelworkers, aged 45 to 55 years, by means of the ECSC-questionnaire and the following lung function tests: vital capacity (VC) and forced expiratory volume in one second (FEV1), residual volume (RV) and total lung capacity (TLC); maximal expiratory flow rates (Vmax, Vmax 50, Vmax 75); specific airways conductance (SGaw); slope of the N2 alveolar plateau after oxygen inhalation (delta N2) and the bolus closing volume (CV). The influence of smoking on respiratory symptoms and lung function was confirmed. In order to assess the influence of occupational pollution a sample of 163 workers was classified according to smoking habits and workplace (either LD-steelplant and continuous casting department, or sheet rolling mill). In the nonsmokers group we found that the workers from the steelplant and continuous casting department (n = 12) had a significantly lower SGaw value (delta = 0.065 cm H2O-1 . s-1, p less than 0.01) and a significantly higher CV value (delta = 4.5% VC, p less than 0.05) than the workers from the sheet rolling mill (n = 11). Differences in FEV1/VC, Vmax 50 and Vmax 75 were not significant, but were also consistent with a slight airflow obstruction in the steelplant workers. In the smokers (n = 99) and exsmokers (n = 41) groups no differences existed between both working categories. Our results suggest that nonsmoking workers from the steelplant and the continuous casting department have undergone moderate, but detectable effects from industrial pollution. These effects are probably masked by those of tobacco in smokers and exsmokers.

Air Pollutants, Occupational↗
PubMedDate not supplied

A germ-free status does not protect from the lethal effects of acute lung damage caused by O,S,S,-trimethyl phosphorodithioate.

To investigate whether a normal resident microbiological flora of conventional rats influences the lethality of chemical-induced lung damage, the pneumotoxin O,S,S-trimethyl phosphorodithioate (OSSMe, 75 or 100 mg/kg, s.c.) was administered to age-matched conventional and germ-free male F344 rats. Microbiological and serological examinations confirmed the germ-free state of the germ-free rats and showed that no specific lung pathogens were present in the conventional rats. As in conventional rats, clinical symptoms and death of OSSMe-treated germ-free rats resulted from respiratory failure. The germ-free rats were not more resistant, but rather more susceptible to OSSMe than conventional rats. Increases in lung weight and histological examination of lung tissue 3 days after dosing with OSSMe (75 mg/kg, s.c.) showed no differences between germ-free and conventional rats. Despite alterations in their nasopharyngeal flora, death in the conventional rats was probably not caused by bacterial superinfection. The higher susceptibility of germ-free rats to OSSMe can be partly attributed to pharmacokinetic differences, since plasma levels of OSSMe decreased more slowly in germ-free than in conventional rats. It is concluded that germ-free rats are not protected from the lethal consequences of acute chemical-induced lung damage.

Animals↗
PubMedDate not supplied

Generalization of acquired somatic symptoms in response to odors: a pavlovian perspective on multiple chemical sensitivity.

OBJECTIVE: Somatic symptoms that occur in response to odors can be acquired in a pavlovian conditioning paradigm. The present study investigated 1) whether learned symptoms can generalize to new odors, 2) whether the generalization gradient is linked to the affective or irritant quality of the new odors, and 3) whether the delay between acquisition and testing modulates generalization. METHODS: Conditional odor stimuli (CS) were (diluted) ammonia and niaouli. One odor was mixed with 7.4% CO2-enriched air (unconditional stimulus) during 2-minute breathing trials (CS+ trial), and the other odor was presented with air (CS- trial). Three CS+ and three CS- trials were conducted in a semirandomized order (acquisition phase). The test phase involved one CS+-only (CS+ without CO2) and one CS- test trial, followed by three trials using new odors (butyric acid, acetic acid, and citric aroma). Half of the subjects (N = 28) were tested immediately, and the other half were tested after 1 week. Ventilatory responses were measured during and somatic symptoms were measured after each trial. RESULTS: Participants had more symptoms in response to CS+-only exposures, but only when ammonia was used as the CS+. Also, generalization occurred: More symptoms were reported in response to butyric and acetic acid than to citric aroma and only in participants who had been conditioned. Both the selective conditioning and the generalization effect were mediated by negative affectivity of the participants. The delay between the acquisition and test phases had no effect. CONCLUSIONS: Symptoms that occur in response to odorous substances can be learned and generalize to new substances, especially in persons with high negative affectivity. The findings further support the plausibility of a pavlovian perspective of multiple chemical sensitivity.

Adolescent↗
PubMedDate not supplied

Air pollution and thrombosis: an experimental approach.

Air pollution is associated with cardiovascular mortality. Inhaled ultrafine particles translocate into the blood. Amine-polystyrene ultrafine particles significantly enhance experimental thrombus formation in a damaged hamster vessel and shorten the closure time in the Platelet Function Analyser. Diesel exhaust particles are thrombogenic within one hour of intratracheal instillation and shorten the closure time ex vivo. These experimental observations provide a plausible biological explanation for the epidemiologically established link between air pollution and acute myocardial infarction.

Air Pollutants↗
PubMedDate not supplied

Decrease in gamma-glutamyltransferase activity in rat type II cells exposed in vitro to hyperoxia: effects of the 21-aminosteroid U-74389G.

Although the effect of hyperoxia on antioxidant enzymes is well known, the effect of subtoxic levels of hyperoxia on gamma-glutamyltransferase (gamma-GT), involved in the degradation and uptake of extracellular GSH for intracellular GSH synthesis, is unknown. The aim of the study was to investigate (1) the effects of in vitro hyperoxia on gamma-GT activity of type II cells and (2) the effects of the lazaroid U-74389G and N-acetylcysteine (NAC) on the hyperoxia-induced changes in gamma-GT and antioxidant enzyme activities. At 48 h after isolation, rat type II cells were exposed for 2 days to air, 60% O2 or 85% O2 with or without 30 microM U-74389G or 100 microM NAC. After the exposure, the cells were harvested and assayed for superoxide dismutase (SOD), glutathione peroxidase (GPx), gamma-GT activity, and GSH levels. In another series of experiments 85% O2-exposed cells, with or without U-74389G, were used for Northern blotting of gamma-GT mRNA. Exposure to 60% O2 decreased gamma-GT and GSH by -47 and -34%, respectively, while SOD and GPx activities remained unchanged. After 85% O2-exposure gamma-GT decreased by -55%, SOD and GPx increased by +55 and +87%, respectively, while GSH decreased by -35%. NAC treatment decreased gamma-GT activity by -42% in the air-exposed cells. After 60% O2, U-74389G led to significantly higher gamma-GT (+117%) and GSH (+26%) while NAC only led to higher GSH (+28%) compared to the oxygen-exposed cells not treated with NAC or U-74389G. After 85% O2 U-74389G increased gamma-GT, SOD, and GSH by +72, +58, and +68%, respectively, while NAC only increased SOD (+49%) and GSH (+26%) compared to the oxygen-exposed cells not treated with NAC or U-74389G. The 85% O2 exposure, with or without U-74389G, had no effect on gamma-GT mRNA levels. The results show that hyperoxia decreases rat type II cell gamma-GT activity in vitro. This effect was not related to an altered regulation at mRNA level and it was not associated with the hyperoxia-induced decrease in intracellular GSH, since restoration of the GSH levels by NAC did not restore gamma-GT activity. The lazaroid U-74389G with vitamin E-like properties effectively prevented the decrease in gamma-GT and GSH, so that direct inactivation of the membrane-bound gamma-GT by hyperoxia is the most likely mechanism.

Acetylcysteine↗