Effect of anti-inflammatory compounds on -irradiation induced radiodermatitis

The effect of several anti-inflammatory agents given <i>per os</i>, intraperitoneally, or topically to alleviate acute radiodermatitis in guinea pig skin following 3,000 or 4,000 rep β-irradiation was studied. Up to the 21st day post-irradiation, there was pronounced suppression of the acute inflammatory response observed with chloroquine diphosphate, or meclofenamic acid (Cl-583). Chloroquine diphosphate given systemically was most potent among the single drugs tested. Qualitatively, combinations of the drugs given <i>per os</i> were somewhat more effective in suppression of the second erythema and late skin reactions. Topical application of 50% DMSO or of anti-inflammatory drugs dissolved in this solvent resulted in increased inflammatory reactions. Triamcinolone acetonide appeared to be the only active compound when applied topically. The effective anti-inflammatory agents decreased the frequency but did not prevent the onset of ulcers. Ulceration was delayed by about 10 days in the drug-treated animals (as compared with its appearance by the 20th day in controls) and the ulcerated area was smaller and healed more rapidly.

Dissociation of low density lipoprotein-antibody precipitates at alkaline pH

The effect of alkaline pH on the dissociation of immunoprecipitates of low density lipoproteins (LDL) of the S(f) 0-10 class was studied by immunological and ultracentrifugal methods. The precipitates prepared at the equivalence point were dissolved and centrifuged in sodium chloride solutions of density 1.063 and pH's between 10.25 and 11.5. Analytical centrifugation of the top fraction, which floated at density 1.063, after dialysis against 0.9% sodium chloride of pH 7.4 revealed the presence of LDL and of soluble LDL-antibody complex. The amount of soluble complex was greater for the preparations obtained at lower pH than those obtained at higher pH and was undetectable at pH 11.5. The yield of immunoglobulin from the bottom fractions was maximal when the pH of the centrifugation medium was 11.0. Below pH 11.0, the greatly reduced yield of immunoglobulin was due partly to incomplete dissociation and partly to aggregation of soluble complex, while above pH 11.0 the decreased yield was possibly due to alkaline denaturation of the globulin. The immunoglobulin separated at pH 11.0 and dialyzed to pH 7.4 was reprecipitatable by LDL, and the reactivity did not seem to be appreciably influenced by the alkaline treatment.