Research report (Health Effects Institute)
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Res Rep Health Eff Inst · Jan 1999
Daily changes in oxygen saturation and pulse rate associated with particulate air pollution and barometric pressure.
Epidemiologic studies have linked fine particulate air pollution with increases in morbidity and mortality rates from cardiopulmonary complications. Although the underlying biologic mechanisms responsible for this increase remain largely unknown, potential pathways include transient declines in blood oxygenation and changes in pulse rate following exposures to particulate air pollution episodes. This study evaluated potential associations between daily measures of respirable particulate matter (PM) with pulse rate and oxygen saturation of the blood. ⋯ Exposure to particulate pollution was not significantly associated with Spo2 except in male participants 80 years of age or older. Increased daily pulse rate, as well as the odds of having a pulse rate 5 or 10 beats per minute (bpm) above normal (normal is defined as the individual's mean pulse rate throughout the study period), were significantly associated with exposure to particulate pollution on the previous 1 to 5 days. The medical or biologic relevance of these increases in pulse rate following exposure to particulate air pollution requires further study.
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Res Rep Health Eff Inst · Jun 1997
Randomized Controlled Trial Comparative Study Clinical TrialEffects of ozone on normal and potentially sensitive human subjects. Part II: Airway inflammation and responsiveness to ozone in nonsmokers and smokers.
Exposure to ozone at levels near the National Ambient Air Quality Standard causes respiratory symptoms, changes in lung function, and airway inflammation. Although ozone-induced changes in lung function have been well characterized in healthy individuals, the relationship between airway inflammation and changes in pulmonary function have not been prospectively examined. The purpose of this study was to determine whether individuals who differ in, lung function responsiveness to ozone also differ in susceptibility to airway inflammation and injury. ⋯ Furthermore, the burden of toxic oxygen species following ozone exposure was greater for smokers than for nonsmokers. Subjects were young, healthy, and able to sustain exercise; the results may not be representative of nonsmokers or smokers in general. Nevertheless, the findings indicate that measuring symptoms and spirometric changes is not sufficient to assess the potential risks associated with ozone exposure.
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Res Rep Health Eff Inst · Oct 1994
Pulmonary toxicity of inhaled diesel exhaust and carbon black in chronically exposed rats. Part I: Neoplastic and nonneoplastic lung lesions.
This study compared the pulmonary carcinogenicities and selected noncancer effects produced by chronic exposure of rats at high rates to diesel exhaust and carbon black. The comparison was intended to provide insight into the likely importance of the mutagenic organic compounds associated with the soot portion of diesel exhaust in inducing pulmonary carcinogenicity in diesel exhaust-exposed rats. The role of the organic fraction has become important in judging the usefulness of the substantial data base on carcinogenicity in rats for predicting lung cancer risk for humans, and for determining the most appropriate method of extrapolating results across species and exposure concentrations. ⋯ These exposures were conducted to examine the clearance of radiolabeled particles and the sequestration of the fluorescent microspheres in the lungs. These experiments provided information on clearance overload and particle dosimetry. The growth characteristics of lung neoplasms also were examined by transplanting neoplastic cells into athymic mice.(ABSTRACT TRUNCATED AT 400 WORDS)
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Res Rep Health Eff Inst · Jul 1994
Nitrogen dioxide and respiratory illness in children. Part III: Quality assurance in an epidemiologic study.
This report describes the quality assurance and quality control program developed for the previously reported epidemiologic study of nitrogen dioxide (NO2) and respiratory illness in children (Health Effects Institute Research Report 58, Parts I and II). The specific aims of the program were to make certain that data were sufficiently accurate, complete, verifiable, and retrievable. The quality assurance and quality control program consisted of: a written protocol, standard operating procedures, written records, a project management system, appropriate data processing, data verification, and data analysis planning, and was staffed by qualified and appropriately trained personnel. ⋯ The second focused quality assurance study evaluated the measurement error associated with the parents' use of passive diffusion samplers for NO2. Midway through the study, technicians conducted home visits to assess compliance with stated procedures, and to make independent measurements of NO2. Based on criteria for placement and use of the samplers, conditions of noncompliance were observed on about 40% of visits.(ABSTRACT TRUNCATED AT 400 WORDS)
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Res Rep Health Eff Inst · Aug 1991
Randomized Controlled Trial Clinical TrialMechanisms of nitrogen dioxide toxicity in humans.
These studies were undertaken to evaluate short-term respiratory effects and identify markers of nitrogen dioxide toxicity during exposures designed to approximate realistic conditions. With the development of bronchoalveolar lavage as a clinical investigative technique, the evaluation focused on the assessment of effects induced at the alveolar level. The exposure protocols were designed to assess the duration of nitrogen dioxide-induced effects and determine exposure-response relationships. ⋯ Following the highest dose of carbachol (10 mg/mL), the forced expiratory volume in one second decreased 7.5 +/- 1.1 percent after nitrogen dioxide exposure compared to 4.8 +/- 1.1 percent after exposure to air (p less than 0.05). No symptoms were induced in any of the groups by the carbachol exposures. Analyses of cells recovered by bronchoalveolar lavage during all three phases revealed no differences in total cell recovery, cell viability, or differential cell counts.(ABSTRACT TRUNCATED AT 400 WORDS)