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M Lippmann

Publications and source records attributed to M Lippmann.

At least 73 records · Page 4Linked to original sources
PubMed1989

Progress, prospects, and research needs on the health effects of acid aerosols.

Research on human exposure to acidic aerosols and the health effects of such exposures has substantially strengthened the hypothesis that such aerosols are a causal factor for excesses in human mortality and morbidity that have been previously associated with crude exposure indices such as British Smoke, total suspended particulate matter, and sulfur dioxide. Research reported at this symposium also showed that combined exposures to acid aerosols and other ubiquitous air pollutants such as O3, NO2, HNO3, and SO2 produce greater effects in both humans and animals than exposures to each agent separately. The responses reported ranged from physiological functions to lung structure. Furthermore, some of the effects were cumulative with increasing duration of daily exposure and number of repetitive exposures. Critical areas for further research include better definition of the critical temporal parameters affecting exposure and response, effects of mixed pollutant exposures, and pathogenetic mechanisms for acid aerosol-induced chronic lung damage.

Acid Rain↗
PubMed1989

Background on health effects of acid aerosols.

This introduction to the 1987 NIEHS-EPA Symposium on the Health Effects of Acid Aerosols reviews the state of our knowledge on this topic as of the close of the 1984 NIEHS Conference on the Health Effects of Acid Precipitation (Environmental Health Perspectives, Volume 63) and the results of some key studies completed since that time. These studies, together with the results of the studies presented in the papers that follow, provide a substantial increment in our knowledge of the health effects of acid aerosols.

Acid Rain↗
PubMed1989

Reexamination of London, England, mortality in relation to exposure to acidic aerosols during 1963-1972 winters.

Air pollution epidemiology since the 1950s has been able to demonstrate that increases in daily mortality in London, England, were associated with elevated concentrations of index air pollutants, i.e., British Smoke (BS) and sulfur dioxide (SO2). In this work, we reanalyze that portion of the 1958-1972 winter mortality-pollution record for which daily direct acid aerosol measurements were made at a central site in London (St. Bartholomew's Medical College). The purposes of these exploratory analyses are to examine the dataset for indications of a relationship between acid aerosol pollution and human mortality and to compare any noted associations with those for other pollution variables. It is found that the log of acid aerosol concentrations is more strongly associated with raw total mortality in bivariate analyses than is BS or SO2, despite the fact that acid data are available from only one central site (versus seven disperse sites for BS and SO2). The logarithmic nature of the exposure side of the H2SO4-mortality relationship implies a saturation model of pollution effects, possibly due to multiday pollution harvesting influences on a susceptible subpopulation. Moreover, mortality-pollution cross-correlation analyses indicate that mortality effects usually follow pollution in time, supporting a causal relationship between the two. The apparent advantage of H2SO4 over BS in predicting total raw mortality is consistent with the hypothesis that it is the portion of particulate mass of greater health significance and may also allow the development of London mortality results which are more easily transferable to other environments than is the case for existing BS results.

Acid Rain↗
PubMed1989

Effective strategies for population studies of acute air pollution health effects.

A series of field studies involving repetitive functional measurements in relatively small populations of healthy children and adults engaged in normal outdoor activities has shown that significant decrements in respiratory function are associated with exposures to ozone (O3) at concentrations below the national ambient air quality standard. The ability to detect such effects can be attributed, at least in part, to the study design criteria used, which emphasized maximization of signal-to-noise ratios. Locations were selected to ensure relatively high exposures to relatively uniformly distributed secondary pollutants, with minimal exposure to local sources of primary pollutants. Populations were selected that would be engaged in active recreation out of doors. Populations of healthy persons were used to minimize variability in baseline function. We found that the magnitude of the O3-associated decrements in respiratory function was dependent on the variability in sensitivity to O3 among the population, the minute ventilation during outdoor activity, and the duration of the outdoor exposure. We also concluded that the O3-associated responses were potentiated by the presence of other air pollutants.

Adult↗
PubMed1988

Boerhaave's syndrome. Computed tomographic findings and diagnostic considerations.

Boerhaave's syndrome, or spontaneous rupture of the esophagus, may present with atypical chest pain mimicking an acute thoracic aortic dissection. We describe such a case and discuss the utility of a thoracic computed tomographic scan in arriving at a prompt diagnosis. The importance of early diagnosis is reviewed with particular attention to these roentgenographic findings.

Aortic Dissection↗
PubMed1988

Asbestos exposure indices.

The ability of inhaled asbestos to produce asbestosis, lung cancer, and mesothelioma in both humans and animals is well established, and asbestos exposures in the occupational and general community environment are recognized as significant hazards. However, it has not been possible to establish realistic and credible dose-response relationships, primarily because of our inability to define which constituents of the aerosols produce or initiate the pathological responses. It is generally acknowledged that the responses are associated with the fibers rather than the nonfibrous silicate mineral of the same chemical composition. Available data from experimental studies in animals exposed by injection and inhalation to fibers of defined size distributions are reviewed, alone with data from studies of fiber distributions in lungs of exposed humans in relation to the effects associated with the retained fibers. It is concluded that asbestosis is most closely related to the surface area of retained fibers, that mesothelioma is most closely associated with numbers of fibers longer than approximately 5 microns and thinner than approximately 0.1 micron, and that lung cancer is most closely associated with fibers longer than approximately 10 microns and thicker than approximately 0.15 micron. The implications of these conclusions on methods for fiber sampling and analyses are discussed.

Animals↗
PubMed1988

Development of an aerosol dispersion test to detect early changes in lung function.

The dispersion of a 0.5 micron aerosol bolus during tidal breathing differs significantly (p less than 0.0001) between a group of smokers (with approximately 20 pack-years average exposure) and a comparable group of nonsmokers. Their mean differences in standard respiratory function indexes from spirometry [forced vital capacity (FVC), forced expiratory volume in one second (FEV1), mean forced expiratory flow during the middle half of the FVC (FEF25-75)] were smaller and not statistically significant. The test is simple to perform and may be done as quickly as spirometry but without using a forced exhalation. Comparison of the coefficients of variation for the dispersion test and FEV1 indicate that the aerosol dispersion test may be useful in epidemiologic investigations either by reducing the required population size or increasing the level of confidence.

Adult↗
PubMed1988

Effects of ambient ozone on respiratory function in active, normal children.

Respiratory functions were measured on a daily basis by spirometry over a period of 4 wk at a summer camp at Fairview Lake in northwestern New Jersey. Fifty-three boys and 38 girls 8 to 15 yr of age participated in the study on at least 7 days; 37 children were in residence for 4 wk, 34 for the first 2 wk only; and 20 for the last 2 wk. There were 72 whites, 15 blacks, 3 Asians, and 1 Hispanic in the study group. Multiple regression analyses indicated that the O3 concentration in the previous hour, the cumulative daily O3 exposure during the hours between 9 A.M. and the function measurement, ambient temperature, and humidity were the most explanatory environmental variables for daily variations in function, with the 1 - h O3 concentration having the strongest influence. Linear regressions were performed for each child between O3 concentration and function, and all average slopes were significantly negative (p less than 0.05) for FVC, FEV1, PEFR, and FEF25-75 for all children, and for boys and girls separately. Comparable results were obtained in data subsets (i.e., children studied during the first or second 2 wk only, and for data sets truncated at O3 less than 80 and O3 less than 60 ppb). The average regression slopes (+/- SE) for FVC and FEV1, respectively, were -1.03 +/- 0.24 and -1.42 +/- 0.17 ml/ppb, whereas for PEFR and FEF25-75 they were -6.78 +/- 0.73 and -2.48 +/- 0.26 ml/s/ppb.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Effects of ambient ozone on respiratory function in healthy adults exercising outdoors.

The effect of exposure to ozone (O3) in ambient air on respiratory function was studied in 30 healthy adult nonsmokers engaged in a regular daily program of outdoor exercise in Tuxedo, NY during the summer of 1985. Each subject did the same exercise each day, but exercise intensity and duration varied widely between subjects, with minute ventilation ranging from 20 to 153 L and duration ranging from 15 to 55 min. Spirometry was performed immediately before and after each exercise period. O3 concentrations during exercise ranged from 21 to 124 parts per billion (ppb). All measured functional indexes showed significant (p less than 0.01) O3-associated mean decrements with FVC at -2.1 ml/ppb, FEV1 at -1.4 ml/ppb, PEFR at -9.2 ml/s/ppb, FEF25-75 at -6.0 ml/s/ppb, and FEV1/FVC at -0.038%/ppb. Mean decrements were smaller for 10 subjects with minute ventilations greater than 100 L than for 10 other subjects with minute ventilations between 60 and 100 L or for the 10 subjects with minute ventilations below 60 L. Overall, the functional decrements were similar in magnitude to those we have seen in children engaged in supervised recreational programs in summer camps. For 10 subjects with minute ventilations comparable to those used in controlled 1- and 2-h exposures to O3 in purified air in chambers (50 to 80 L), the effects were about twice as large as those reported for the chamber studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Effect of lung airway branching pattern and gas composition on particle deposition. I. Background and literature review.

This paper reviews (1) the influence of airflow and particle motion on particle deposition within human lung airways, (2) the effects of carrier gas properties on mass transport in lung airways, and (3) the differences in particle deposition patterns and efficiencies between humans and experimental animals. The primary purpose of this review of general principles and available literature is to identify critical factors affecting the dosimetry of inhaled toxicants. Special attention is paid to studies utilizing gases of varying composition, which illuminate the role of flow profiles and turbulence in gas and particle penetration, and to studies of the effects of interspecies differences in airway branching patterns on particle deposition patterns within the airways.

Animals↗
PubMed1988

Effect of lung airway branching pattern and gas composition on particle deposition. II. Experimental studies in human and canine lungs.

The recovery of monodisperse inhaled particles from humans in vivo and from excised human and canine lungs was measured after a single breath for particles suspended in air and in mixtures of He or SF6 with O2. Comparisons were made using the unique particle sizes for which the intrinsic particle motions in air and each mixture were identical, so that differences in recovery could be associated with differences in convective flow. For the in vivo tests, only mixtures with 20% O2 were used, while for the excised lungs, mixtures with 10% O2 were also used. In humans in vivo and in excised human lungs, there was significantly greater deposition from He-O2 mixtures and less deposition from SF6-O2 mixtures, with no differences between the in vivo and the excised lung results for the 80-20 mixtures. For the canine lungs, there were no differences in deposition between air and any He or SF6 mixture. The interspecies differences are consistent with the hypothesis that particle exchange between tidal and residual lung gas is dependent on the distance into each airway that is needed to establish a stable flow profile. The more symmetrical branching of human lung airways causes the entry flow into daughter airways to be highly asymmetric, and flow profile rearrangement is greater than that in the monopodal canine lung.

Adult↗
PubMed1987

Increased outputs of lymphocytes in lymph efferent from the lymph nodes of sheep during systemic arterial hypertension induced by phenylephrine or dopamine.

Induced systemic arterial hypotension by intravenous nitroprusside administration and by acute arterial occlusion in sheep have been found to reduce lymphocyte traffic as mirrored in the output of lymphocytes into the efferent lymph of peripheral lymph nodes. In the present series of experiments in sheep with chronically cannulated efferent lymphatics of peripheral lymph nodes, induced and monitored systemic arterial hypertension with intravenous pump infusions of phenylephrine or dopamine both produced sharp increases in the output of lymphocytes into efferent lymph in all of 27 studies. The increases in lymphocyte output with dopamine were more sustained and less associated with evidence of lymphoid tissue damage than with phenylephrine. Phenylephrine infusions were attended by a high incidence of gross bleeding into the efferent lymph, of increased coagulability of efferent lymph in the absence of gross bleeding and of prolonged depression of lymphocyte outputs after the cessation of intravenous infusion.

Animals↗
PubMed1987

Angiotensin converting enzyme in bronchoalveolar lavage in ARDS.

Angiotensin converting enzyme (ACE) is present in the endothelial cells of the normal lung where it converts angiotensin I to angiotensin II and inactivates bradykinin. It has been suggested that during endothelial injury ACE is sloughed into the blood, and that if the alveolar capillary membrane is injured, also into the alveolar lining fluid. Seven patients with adult respiratory distress syndrome (ARDS), were compared to 11 normal control subjects, nine patients with sarcoidosis, and six with idiopathic pulmonary fibrosis. Total, differential cell counts and ACE determinations were performed on bronchoalveolar lavage fluid in the ARDS group. ACE was detectable in the BAL of all but one ARDS patient. It was concluded that BAL ACE is elevated in some ARDS patients, especially those with infectious causes of lung injury. Increased ACE may reflect endothelial damage or local increase in ACE production in response to sepsis.

Adult↗
PubMed1987

Criteria and standards for occupational exposures to airborne chemicals.

Prevention of occupational exposures to chemicals at levels that can cause illness or disease depends upon having exposure limits, methods for measuring exposures, and means for limiting exposures to levels within the established limits. The development and applications of exposure standards (that is, legal limits, and other guidelines used as professional practice criteria in the U.S. and Europe) are reviewed and discussed. Biological exposure indices, which can be used to supplement direct measurements of exposures, are also discussed.

Air Pollutants, Occupational↗
PubMed1986

Airborne particles, their use in the respiratory system to measure air flow, function, and clearance.

Nonhygroscopic monodisperse particles can be used to estimate airway dimensions within chosen regions of the respiratory tract. These dimensions correspond well with those measured in inflation-fixed lungs. The dispersion of a bolus of airborne particles on inhalation and exhalation is very sensitive to the dimensions of the airways through which the bolus passes, yielding indices of dispersion that provide sensitive indicators of changes in airway dimensions, eg, with smoking. The rates of clearance of particles from the lungs are determined using gamma-labelled particles whose lung retention is determined by external measurements. There are major differences between the deep lung and the ciliated airways. Changes in clearance rates are caused by disease or inhaled intoxicants such as cigarette smoke. At lower levels of irritant exposure, an acceleration of clearance rate is observed, while higher doses and longer periods of exposure produce decreased rates. It is suggested that aerosol techniques may have useful clinical applications; approaches are suggested for such applications.

Adult↗