Effects of heat stress on nitrogen dioxide toxicity in monkeys.
Coate-WB; Schoenfisch-WH; Busey-WM; Badger-DW
Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Contract 099-72-0095, 1974 Jan; :1-26
In order to assess the effects of hot environments on nitrogen-dioxide (10102440) toxicity, groups of 10 male cynomolgus monkeys were exposed continuously for 90 days to 5 and 10ppm of nitrogen-dioxide at 72 and 88 degrees effective temperature. Air control groups were maintained at the respective effective temperatures. Hematological studies included CBC, methemoglobin, plasma volume, and red cell survival. Serum chemistry, blood gases, chest X-rays, and body weights were monitored. Pulmonary function tests were conducted. The results indicated that nitrogen-dioxide at 10ppm impaired distribution of ventilation of the lungs, increased respiratory rate, and decreased tidal volume. The addition of heat stress to this level of nitrogen-dioxide exposure did not further impair distribution of ventilation but it decreased dynamic compliance of the lungs whereas nitrogen-dioxide alone did not. The combination of 10ppm of nitrogen-dioxide and heat stress resulted in a mean loss in body weight over the 90 day exposure whereas all other groups gained weight. No effects on airway resistance were obtained. General observation indicated that the animals were extremely hypoactive in the chambers at 88 degrees of effective temperature with and without nitrogen-dioxide. No synergistic effects of heat stress were found at 5ppm of nitrogen-dioxide. Nitrogen-dioxide related microscopic alterations were seen in the respiratory bronchioles, alveolar ducts and adjacent interalveolar septa. No microscopic morphological effect of heat stress was seen in the lungs from either the nitrogen-dioxide exposed or control monkeys.
NIOSH-Contract; NIOSH-Author; Contract-099-72-0095; Nitrogen-oxides; Toxic-gases; Heat-stress; Environment; Respiratory-functions; Respiratory-system-disorders; Blood-chemistry; Histopathology; Interactions
Final Contract Report
National Institute for Occupational Safety and Health
Hazleton Laboratories, Inc., Vienna, Virginia