Harry Sobel

The collagen and hexosamine content of the skin of normal and experimentally treated rats

Abstract The collagen and hexosamine contents of the skin of growing rats were determined. Regression equations were derived upon the basis that there is a linear relationship between the logarithm of body weight and logarithm collagen, logarithm body weight and logarithm hexosamine, logarithm body area and logarithm collagen, and logarithm body area and logarithm hexosamine. The collagen content of the skin increases much more rapidly than the increase in weight. The hexosamine content increases with weight more nearly in a proportional manner so that the ratio of hexosamine to collagen falls as the weight increases. Several pilot experiments were carried out to determine the effects of a variety of factors upon the production of hexosamine and collagen in skin.

Collagen and hexosamine content of femurs of rats.

Summary The collagen and hexosamine contents of the femurs of growing rats were determined. Regression equations were derived upon the basis that there is a linear relationship between the logarithm of body weight and of femur length and the logarithm of the quantity of collagen and hexosamine. Rate of collagen deposition decreases somewhat as the animal grows. Rate of deposition of hexosamine-containing material, decreases markedly so that the ratio of hexosamine to collagen decreases with growth.

Effect of cortisone on connective tissues of the rat.

Summary The effect of cortisone administration upon the hexosamine-collagen ratio (H/C) of several tissues was investigated. The H/C of skin, sternum, trachea, lung, aorta and vena cava was significantly reduced when a 20% loss in weight was induced by cortisone. When injections were discontinued and the original weight was regained, H/C of sternum and vena cava returned to starting level. This was nearly true of lung and aorta. Skin lagged behind considerably in this respect. Multiple biopsies were taken from skin following cortisone administration and withdrawal. When depression of H/C was greatest, recovery lagged the most. The findings are pertinent to the question of the general nature of cortisone effect upon connective tissue and the reversibility of this effect.

Spontaneous and Stress-Induced Myocardial Infarction in Aged Atherosclerotic Dogs

Male, mongrel dogs, six to eight years of age, were placed on an atherogenic regimen which included I131 administration and/or thiouracil with cholesterol feeding and, in some cases, the addition of 10 per cent lard to the diet. As is usually observed in such experiments, the degree of hypercholesterolemia and atheromatosis varied greatly. However, in nine out of ten dogs with blood cholesterol levels of 1,800 mg. per cent or above for over 16 weeks, myocardial infarction appeared (a) spontaneously, (b) after pitressin administration, and (c) after exposure to a stresser. Myocardial infarction has been noticed only rarely previously. Reasons are given for the belief that the advanced age of the animals which were used here played a role in the genesis of infarction.

Hexosamine-Collagen Ratio of Skin Biopsies in Patients Receiving Systemic Corticosteroids.

Summary Dermal punch biopsies were obtained from 41 subjects prior to and following 2 weeks of daily medication with prednisone, methyl prednisilone or triamcinalone. The hexosamine-collagen ratio (H/C) was determined. In 32 subjects decrease in H/C values of 5% or greater were observed. The mean change in H/C in 35 patients following corticoid treatment was −12.9% ±1.5%. Analysis of skin punches for hexosamine and collagen was carried out by George Bonorris.

Effect of Co++, Ni++, and Zn++ on Corticoid Excretion by the Guinea Pig.∗

Summary Several divalent ions were administered intraperitoneally to guinea pigs, at a dose of 4 μM 100 g body weight. Urinary corticoid excretion was doubled by Co++, Ni++ and Zn++, Fe++, Cu++, Hg++, and Pb++, produced little or no effect upon corticoid excretion.

Pigmy marmoset as an experimental animal.

The pigmy marmoset has been maintained under laboratory conditions for approximately � years. A synthetic diet has been prepared, which includes milk, eggs, and lard, which may cause fourfold increase in serum cholesterol levels. This species is proposed as an experimental subject for the study of aging and age-associated diseases.

Effect of Cortisone on Survival of Morphine Treated Guinea Pigs under Decompression Hypoxia.

Summary Mortality of 37% was induced in guinea pigs under decompression to a simulated altitude of 25.000 feet for 6 hours. Morphine sulfate increased mortality to 50%. and 75% if administered at dose of 2.5 mg or 5 mg 100 g body weight respectively. Prior treatment with cortisone for 3 days reduced mortality to 22% and 29% respectively. Multiple injections with ACTH reduced mortality to 19%.

ACTH releasing factor active in the guinea pig.

Summary Lysine vasopressin was obtained from commercial pitressin powder by electrophoretic separation. The ACTH releasing activity in the guinea pig and the pressor activity in the cat were compared following various chemical manipulations. Following mild acid and alkaline hydrolysis, iodination, and incubation with placental extract both activities are altered to the same extent. It was concluded that lysine vasopressin causes ACTH release in the guinea pig. This is consistent with the concept that it may be a hypothalamic mediator in this species.

The rates of growth of protein fractions of the heart and kidney of the rat.

Abstract The procedure for fractionating the proteins of a single rat heart has been modified for the kidney. The quantity of each protein fraction of the heart and kidney has been studied for female rats of the Addis-Slonaker strain, ranging in age from 4 weeks to 1 year. Regressions were derived correlating the quantity of protein of each fraction with the weight of the rat. The growth rate of each fraction was calculated. It was observed that there were wide individual differences. For example α-myosin and β-myosin in the heart grow at a greater rate than other protein fractions. It is suggested that the rate of growth of a particular protein fraction may be dependent upon the demands placed upon it.