Richard Ehrlich

Chronic toxicity of nitrogen dioxide. I. Effect on resistance to bacterial pneumonia

Continuous (24 hr/day) exposure to 0.5 ppm nitrogen dioxide (NO2) for three months or longer significantly increased the susceptibility of mice to airborne Klebsiella pneumoniae as demonstrated by enhanced mortality. Intermittent exposure to 0.5 ppm NO2 for 6 or 18 hr/day for six months also resulted in a significantly increased mortality. After 12 months’ exposure to NO2, mice in the three experimental groups

Chronic Exposure to Nitrogen Dioxide

Squirrel monkeys continuously exposed to 1 ppm of nitrogen dioxide (NO2) for 493 days were challenged five times with monkey-adapted influenza A/PR/8/34 virus. All monkeys exposed to NO2 produced serum neutralization antibody within 21 days after virus infection, whereas only one control monkey exposed to filtered air showed comparable response. The differences observed in hemagglutination-inhibition antibody titers, body temperatures, respiratory functions, body weights, and hematological values between the experimental and control monkeys were not significant. Histopathologic examination of lung tissues indicated slight emphysema and thickened bronchial and bronchiolar epithelium only in monkeys exposed to NO2 and challenged with the influenza virus. Transmission election microscopic examination did not disclose any ultrastructural changes that could be attributed to the experimental exposures.

Chronic toxicity of NO2 in squirrel monkeys. 3. Effect on resistance to bacterial and viral infection.

Monkeys were exposed to 10 ppm NO/sub 2/ for 1 month and 5 ppm for 2 months prior to challenge with Klebsiella pneumoniae or influenza virus. Minute respiratory volumes of monkeys exposed to 10 ppm were elevated after 2 weeks and remained high throughout exposure (increase in tidal volume and rate). Challenge reduced minute volume of exposed monkeys but increased volume of control monkeys. With 5 ppm exposure, tidal volume gradually decreased, but respiratory rate increased to maintain minute volume. Subsequent exposure to K. pneumonaie produced death in 25 to 28% of NO/sub 2/-exposed monkeys. Bacterial clearance also was reduced. With viral infection, 6/6 in 10 ppm group died; 1/3 in 5 ppm group died. No controls died in either case.

Effect of Nitrogen Dioxide on Resistance of Squirrel Monkeys to Klebsiella pneumoniae Infection

Monkeys were exposed to single 2-hr insults of 10, 15, 35, and 50 ppm NO/sub 2/. At lower concentrations tidal volume decreased but returned to normal in 1 to 2 days. Two higher exposures increased respiratory rate and decreased tidal volume, effects which lasted 2 to 3 days. 50 ppm NO/sub 2/ plus bacterial challenge produced mortality. Lower concentrations of NO/sub 2/ reduced or eliminated lung bacterial clearance.

A tracer method for the determination of microgram quantities of protein.

Abstract A technique is described which utilizes radioactive tungsten for the determination of protein concentrations in the range of 1–10 μg/ml. It has been noted that Ag + , Sr ++ , Y +++ , and the tantalate anion are all bound to protein to some extent, while Tl + is not bound. A suggestion is made that the numerous radioactive ionic species now available might well be applied to further studies of ion binding by proteins.

Chronic Toxicity of NO2 in Squirrel Monkeys

Monkeys were exposed to 10 ppm NO/sub 2/ for 1 month and 5 ppm for 2 months prior to challenge with Klebsiella pneumoniae or influenza virus. Minute respiratory volumes of monkeys exposed to 10 ppm were elevated after 2 weeks and remained high throughout exposure (increase in tidal volume and rate). Challenge reduced minute volume of exposed monkeys but increased volume of control monkeys. With 5 ppm exposure, tidal volume gradually decreased, but respiratory rate increased to maintain minute volume. Subsequent exposure to K. pneumonaie produced death in 25 to 28% of NO/sub 2/-exposed monkeys. Bacterial clearance also was reduced. With viral infection, 6/6 in 10 ppm group died; 1/3 in 5 ppm group died. No controls died in either case.

Application of membrane filters.

Publisher Summary This chapter illustrates membrane filtration that has been evaluated by numerous investigators in the field of public health. It is used in analysis of water for determining the presence of coliform and various pathogenic organisms. Membrane filtration is used for isolation of specific microorganisms, such as E. coli, S. typhosa, M . tuberculosis, B . suis, Bacillus anthracis, and various yeasts and pollens. In the dairy industry, membrane filters are used in bacteriological analysis of milk, sterilization of liquid additives, routine checks of water supplies, and examination of containers and pipes. In medical or clinical procedures, membrane filters are utilized for analysis of sputum, spinal fluid, and urine. The sputum, urine, or spinal fluid must be treated prior to the filtration. In aerobiology, membrane filtration can be used for collection and analysis of pollen and bacteria. While membrane filter retention of organisms directly collected from air did not present any special difficulties, the maintenance of the viability of the organisms can be a problem.