Water deprivation and food restriction on toxicity of parathion and paraoxon.

Three groups of rats were injected intraperitoneally with either parathion or paraoxon: (1) rats deprived of water for 48 hr, (2) rats allowed water ad lib but restricted in food intake to equal that consumed by water-deprived rats, and (3) controls. Following injection of parathion all groups showed a progressive decrease in enzymatic hydrolysis of acetylcholine over a 2-hr period. The decrease was significantly greater in food-restricted rats. Injection with paraoxon resulted in an immediate decrease in red cell cholinesterase activity, which remained low for 1 hr, but recovered thereafter. The esterase activity of both deprived groups was significantly lower than that of controls. These experiments suggest that persons subject to nutritional deficiency and water deficit may be abnormally susceptible to the effects of anticholinesterase pesticides.

The early days of industrial hygiene--their contribution to current problems.

This Herbert E. Stokinger Lecture, directed to the post-1970 industrial hygienists, describes the concepts and contributions of the early industrial hygienists in 1) the determination of standards-TLVs; and 2) the methods of obtaining better working conditions in industry. The scientists who developed the data and proposed the TLVs clearly understood their limitations and the many variable factors in applying these in industry, hence TLVs were suggested only as guides which allowed initiative, experimentation and value judgment by industrial hygienists. Industrial hygiene administration in the 1930's and '40's was the responsibility of state and local health departments (except in two states). In contrast to OSHA's penalty system, the philosophy was to educate and assist industry to understand their health problems and to advise them how to develop safe and healthy working conditions. Special emphasis was placed on small plants. These programs were very successful in most states. Because of OSHA's inability to inspect the small plants, it is recommended that those plants with less than 100 employees be removed from OSHA's jurisdiction and placed under the supervision of special divisions of state and local health departments, financed by USPHS funds, and that the type of service to these small industries be similar to that in the 1930's.

Water deprivation and food restriction on pulmonary bacterial defenses in mice.

Mice deprived of water for 48 hr, mice allowed water but restricted in food intake to equal that consumed by the water-deprived mice, and control mice were exposed for 30 min to an aerosol of Serratia marcescens. Comparison of the number of organisms in the lungs of mice killed immediately after infection and those killed 4 hr later showed a normal reduction over the 4-hr period in the control mice. A significant increase, however, was observed in the water-deprived mice and an even greater increase in the food-restricted mice allowed water. The results did not correlate directly with the lung weight or lung water content. This reduction in bacterial defense could not be assigned solely to either water or food restriction.

Effect of water and food deprivation on hepatic microsomal metabolism of hexobarbital and aniline.

Water deprivation for 48 hr with its accompanying decrease in food intake significantly lowered the in vitro rate of hexobarbital metabolism by hepatic microsomes isolated from male rats. Pair-fed rats allowed water ad libitum had a significantly lower level of hexobarbital metabolism than those deprived of water. Rats starved for 24 hr with or without water also had levels of hexobarbital metabolism significantly lower than their controls; with those animals allowed water ad libitum, the level was significantly lower than for those deprived of water. In vivo hexobarbital "sleeping time" experiments were in general agreement with these results. The in vitro metabolism of aniline was increased in both male and female rats following 24 hr starvation and in female rats (but not males) the effect was greater when water was allowed than when deprived. The differences between hydrated and dehydrated animals were not attributable to reduction in concentration of microsomal protein or the water content of liver. It is concluded that water consumption accentuates the effect of food deprivation on hepatic microsomal metabolism.