Search PubMed⌕ Search

Biomedical subjects

M Lippmann

Publications and source records attributed to M Lippmann.

221 records · Page 13Linked to original sources
PubMedDate not supplied

Effect of chronic inhalation of sulfuric acid mist upon mucociliary clearance from the lungs of donkeys.

The effect of chronic inhalation exposures to sulfuric acid mist upon mucociliary clearance from the lungs was studied, using the donkey as an analogue for man. Four animals were exposed 1 hr/day, 5 days/week, for 6 months. The mean mass concentration of acid mist was 102 microgram/m3 for two animals, and 106 microgram/m3 for the other two. The mass median aerodynamic diameter was approximately 0.5 micrometer. Clearance was monitored by serial, external in vivo measurements of the retention of an insoluble, radioactively tagged ferric oxide aerosol which was inhaled following exposure to the acid mist. Bronchial clearance became erratic within the first week of exposure; rates were significantly different, usually slower than control on many test days, although the degree of response varied among the four animals. Two animals exhibited a sustained impairment of clearance towards the end of the 6-month exposure period and continued to have erratic clearance during a 3-month follow-up period. No changes in the regional deposition of the ferric oxide occurred during the course of the study in any of the animals. It is proposed that alterations in bronchial mucociliary clearance may be an early, if not the first, physiologic effect resulting from the inhalation of sulfuric acid mist, and this may be a factor in the pathogenesis of chronic bronchitis in populations exposed to the sulfur oxide-particulate-complex in the ambient air, which often includes sulfuric acid.

Aerosols↗
PubMedDate not supplied

Health effects of tropospheric ozone: review of recent research findings and their implications to ambient air quality standards.

The U.S. Environmental Protection Agency (EPA) Administrator proposed (on August 3, 1992) to retain the current National Ambient Air Quality Standard (NAAQS) for ozone (O3) on the basis of data assembled in a draft Criteria Document (1986) and its Addendum (1988) which, together with a draft Staff Paper (1988), received public comment and review comments by the EPA's Clean Air Scientific Advisory Committee (CASAC). This paper summarizes and discusses research findings presented since 1988 which, based on the author's experience as a Chairman of CASAC, are most relevant to the promulgation of a primary (health based) NAAQS for O3. These newer findings include substantial evidence from controlled chamber exposure studies and field studies in natural settings that the current NAAQS contains no margin of safety against short-term effects that the EPA has considered to be adverse. They also include evidence from epidemiologic studies that current ambient exposures are associated with reduced baseline lung function, exacerbation of asthma and premature mortality, as well as evidence from chronic animal exposure studies at concentrations within current ambient peak levels that indicate progressive and persistent lung function and structural abnormalities. The current NAAQS, if retained, may therefore also be inadequate to protect the public from effects resulting from chronic exposure to O3.

Adult↗
PubMedDate not supplied

Sulfate concentrations as an indicator of ambient particulate matter air pollution for health risk evaluations.

Retrospective population studies that have compared regression coefficients for mortality and morbidity for sulfate (SO4(2-), fine particles (PM2.5; aerodynamic diameter < 2.5 microns), thoracic particles (PM10; aerodynamic diameter < 10 microns), and total suspended particulates (TSP; undefined and variable upper cut-size) generally have found SO4(2-) concentrations to be correlated with effects as well as or better than PM2.5. In addition, both SO4(2-) and PM2.5 have yielded somewhat stronger associations with adverse health effects than PM10, and much stronger associations than TSP. Sulfate has advantages over PM2.5 for retrospective epidemiology, at least in the United States, because considerably more data on sulfate have been collected in recent decades, and there is a broader epidemiological database in the literature for comparison to other studies. While SO4(2-), per se, is an unlikely causal factor for mortality or morbidity, it often is correlated closely with variations in the strong acid component of ambient particulate matter (H+) and PM2.5 concentrations (especially in summer), which are more likely causal factors. A detailed analysis of the SO4(2-) epidemiological database is presented in this paper. In addition, drawing on our substantial archives of SO4(2-) and H+ data, we show that SO4(2-) and H+ correlate, both spatially and over time, in the eastern United States. We demonstrate the utility of SO4(2-) as a useful surrogate for ambient PM2.5 and H+ in epidemiological studies and as an index of PM exposure in ambient air quality guidelines and standards.

Aerosols↗
PubMedDate not supplied

Peak flow rate changes in O3 exposed children: spirometry vs miniWright flow meters.

We compared "miniWright" peak flow (mWPF) readings with spirometric peak expiratory flow rates (PEFR) in 91 children, aged 8-15, exposed to ambient air at a summer camp in northwestern New Jersey. mWPF measurements immediately preceded spirometry, and mWPF-PEFR differences were regressed on spirometric PEFR by child. The ratio (mWPF-PEFR)/PEFR (mean +/- SE) was -0.027 +/- 0.028 (n = 91) (NS). When subdivided into PEFR ranges, the ratios were: -0.089 +/- 0.060 (n = 17) for 2-<4 Liters/second (Lps) (p = 0.04), -0.019 +/- 0.038 (n = 50) for 4-<6 Lps (NS); and -0.000 +/- 0.044 (n = 24) for 6-<8 Lps (NS). The mWPF values were also regressed on the average ozone (O3) concentration in the previous hour, by child. The mWPF response for O3 was -6.63 +/- 0.76 mL/sec/ppb, compared to -6.78 +/- 0.73 mL/sec/ppb O3 for PEFR. Thus: 1) mWPF, with an overall underestimation of approximately 2%, is a useful surrogate for spirometric values of PEFR (although, for the smallest children studied, it underestimated peak flows by approximately 9%), and 2) the portable miniWright peak flow meter is a convenient and effective tool for characterizing changes in PEFR associated with exposures to ambient O3.

Adolescent↗