Jeffress G. Palmer

Distribution and Clearance of Circulating Endotoxin.

To elucidate the mechanisms of endotoxin action the distribution and clearance of injected endotoxin were studied in New Zealand white rabbits; some animals were rendered tolerant through successive (5 days) doses of endotoxin (E. coli lipopolysaccharide) and the remainder were nontolerant. Blood and plasma clearance of small doses of chromium-labeled endotoxin was more rapid in tolerant than in nontolerant rabbits. In both groups clearance was nearly complete within 10 minutes after injection. Circulating endotoxin was distributed between plasma and platelets in both non- and tolerant animals. A minimal amount of endotoxin was found in leukocytes by this was believed the result of contaminating platelets.

A method for the study of the incorporation of inorganic radiophosphorus into leukocyte deoxyribonucleic acid

Abstract A modification of the Schmidt-Thannhauser procedure for isolating DNA coupled with a new method for DNA digestion and an adaptation of the Berenblum and Chain method for phosphorus determination have been shown to be suitable for use in studying the incorporation of inorganic P 32 into leukocyte DNA. With these techniques tracer doses as small as 2 μc/kg are permitted. Peak tagging of rabbit leukocytes was found to occur on the fourth day following injection. Disappearance of the label through the tenth day was virtually exponential.

Effect of Phosphate Loading on Leukocyte Labelling with Inorganic P32.

Summary The effect of an intravenous load of non-isotopic inorganic phosphate following P32 on plasma clearance and on leukocyte labelling has been studied. Such a load produces immediate dilution of plasma phosphate activity, decreases rate of clearance of plasma radioactivity during the period of loading, diminishes the level of labelling of circulating leukocyte acid soluble and DNA phosphorus, and prevents development of a peak in DNA-P specific activity. The findings suggest that marrow labelling during the first 2 hours after P32 injection is responsible for development of the peak in DNA-P specific activity found in peripheral blood leukocytes.