A comparison of internists in solo and fee-for-service group practice in the San Francisco Bay area.
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California↗
Biomedical subjects
R M Bailey
Publications and source records attributed to R M Bailey.
Controlled exposure to a mixture of SO2, NO2, and particulate air pollutants: effects on human pulmonary function and respiratory symptoms.
Exposure of 20 volunteers to sodium chloride (NaCl) aerosol or to a mixture containing NaCl plus irritant particles (zinc ammonium sulfate) and irritant gases (nitrogen dioxide and sulfur dioxide) produced no significant decrements in pulmonary function. There was a slight tendency for respiratory symptoms to be greater during the exposure to the mixture than during exposure to the NaCl aerosol alone; the differences were not statistically significant. The pollutant concentrations studied approximated worst-case ambient levels observed in the Los Angeles basin.
Adolescent↗
Effects of 0.2 ppm nitrogen dioxide on pulmonary function and response to bronchoprovocation in asthmatics.
To study the respiratory effects of nitrogen dioxide (NO2) at ambient concentrations, we exposed 31 asthmatic volunteers to purified air (control) and to 0.2 ppm NO2 for 2-h periods with light intermittent exercise. Bronchial reactivity (loss of forced expiratory performance in response to graded doses of methacholine chloride aerosol) was determined postexposure, using a newly developed apparatus that allowed accurate quantitation of methacholine dose. Forced expiratory performance, total respiratory resistance, and symptoms were also recorded immediately pre- and postexposure (prior to methacholine challenges). No significant direct effect of NO2 exposure on forced expiratory function or total respiratory resistance was observed. Symptoms showed a small significant (p less than 0.05) excess in purified air relative to NO2 exposures. Individual responses to methacholine varied greatly. About two-thirds of the subjects showed greater response after NO2 than after purified air, but the mean excess response was small. Mean changes attained significance in some but not all applicable statistical tests. Thus we cannot conclude unequivocally that NO2 exposure increased bronchial reactivity in this group, although there was some tendency in that direction.
Adolescent↗