J. Maxwell Little

Dietary protein level and experimental aortic atherosclerosis.

White Carneau pigeons were fed diets containing three levels of protein (compensated for by changes in the dextrin level); all other dietary constituents, including cholesterol, were at the same level, and these diets were fed for nine months, when the birds were killed and necropsied. Group A, which was fed the lowest level of dietary protein (10%), which is considerably less than that in Pigeon Chow Checkers, showed a high mortality rate (50%) and the survivors showed a significant loss in body weight. The birds in the other two groups, B and C (20 and 40% protein respectively) showed no significant changes in body weight during the experiment. When the mean serum uric acid values for the last four blood sampling periods, at two months intervals, in the last seven months of the experiment were compared with the values for A, only Group C showed a significant increase. There was no significant difference in serum total cholesterol concentrations, when compared in the same way. There were no significant changes in either the aorta atherosclerosis indices or the mean aorta cholesterol concentrations, determined after necropsy. If one compares the serum total cholesterol concentration for the groups of pigeons, of the blood samples drawn the day before they were killed, there were significant increases observed for Groups B and C. This work does not support the suggestion previously made that the dietary protein cholesterol interact in determining the concentration of aorta cholesterol and the atherosclerosis index in this breed of pigeon.

Diuretic Activity of Three Primary Fractions of Total Nondialyzable Solids From Human Urine.

Summary The total nondialyzable solids of normal human urine have been partially fractionated by ultrafiltration yielding an ultrafilterable fraction (UFO) and a residue, fraction RO. The latter has been fractionated further by extraction with barbital-sodium barbital buffer, pH 8.6, yielding a soluble fraction RSI and an insoluble residue fraction Rl. A significant increase in rate of urine flow in dogs was obtained by intravenous administration of fraction RSl in a dose range of 0.5–10 μg/kg. On a weight basis fraction RSl is much more potent than acetazolamide or chlorothiazide, under the conditions of the assay. Fraction UFO did not result in an increase in urine flow when given in a dose range of 0.5–2 μg/kg. Fraction Rl could not be assayed in the dog because of toxicity, but when administered as a suspension intraperitoneally in doses of 20–25 μg/100 g to the rat it resulted in appreciable increases in rate of urine flow and electrolyte excretion.

Vasodilator Effects of a Substance Present in Normal Human Urine in Comparison with the Effect of Methacholine and Sodium Nitrite A Statistical Analysis of Reliability of the Method of Assay

This paper presents a method for bioassay of vasotropic substances. Data on the accuracy of the method are presented in terms of the response to repeated injections of methacholine. Some of the factors affecting the response to methacholine are analyzed. The peripheral vasodilator effect of a nondialyzable substance present in human urine is demonstrated and the effectiveness of this substance is related to that of methacholine.

Paradoxical result obtained with the Hickey-Hare test for diabetes insipidus: With a note on the regulation of chloride excretion

Abstract In a patient with polyuria the results obtained with the Hickey-Hare test were consistent with a normally functioning hypothalamic-hypophyseal mechanism as far as the urine excretion rate was concerned but were not consistent with normal function with respect to the changes in the chloride U/P ratio. The patient responded in a similar manner to the injection of pitressin. Some factors influencing the excretion of chloride and the relationship of the posterior pituitary gland to chloride regulation are discussed.

Perirenal Hemorrhage in Ureter Ligated Dogs Receiving Phthalyl-sulfathiazole

Summary The ureters were ligated in 6 dogs, and phthalylsulfathiazole was administered orally in doses of 0.5 to 0.75 g/kg/day for 3-6 days pre-operatively and postoperatively until death. Two of these animals showed at autopsy an increased vascularity of the fascial sheath covering the perirenal fat, 5 animals showed perirenal sheath hemorrhage, and 3 animals had fresh free blood in the abdominal cavity. The ureters were ligated in 6 control dogs, and they received no phthalylsulfathiazole. Four of these animals showed at autopsy an increased vascularity of the perirenal sheath. None of the animals showed perirenal hemorrhage. It was found that both ureter ligation and phthalylsulfathiazole administration are necessary for production of the perirenal lesions. It appears that the perirenal hemorrhage is due to vascular changes since no abnormalities in prothrombin time, bleeding, clotting, and clot retraction time, red blood cell counts or platelet counts were demonstrated. The average total blood sulfathiazole concentration at the time of death in the test animals was 2.9 mg %.