Paul R. Patek

Effect of Angiotensin on Juxtaglomerular Cells and Vessels of the Kidney

Angiotensin II, given subcutaneously in pressor doses to rats three times a day, causes a prompt increase in the size and granulation of the juxtaglomerular cells. After one week of angiotensin injections, there is some loss of granules from these cells. Concurrently, degenerative changes develop in the intrarenal arteries. These changes may result from vasoconstriction in the vessels proximal to the afferent arterioles. Epinephrine given in an amount similar in pressor effect to angiotensin II did not produce these changes. Vascular lesions were not seen in the heart, lung, brain, aorta, liver, and spleen of animals given angiotensin over the two-week injection period. This study provides additional evidence that the vessels of the kidney are uniquely sensitive to angiotensin.

Lymphatic Vessels of the Dental Pulp in Dogs

Lymphatic vessels of the pulp were traced in the teeth of dogs. At the coronal surface the lymph capillaries originated as blind beginnings in the pulp proper near the zone of Weil, whereas they are found adjacent to the odontoblastic layer on the lateral surfaces. These capillaries emptied into collecting lymph vessels that coursed apically to exit through the apical foramens to finally drain into the alveolar lymphatic vessel.

Inhibition of coronary atherosclerosis in the x-irradiated, cholesterol-fed rat by chondroitin sulfate A.

Summary Lipid-containing atherosclerotic coronary lesions were produced in rats exposed to a single dose of 600 r total body x-irradiation and subsequently fed a cholesterol-containing diet. Non-irradiated rats fed a similar diet did not develop such lesions nor did x-irradiated rats fed a cholesterol-free diet. The incidence and extent of lipid deposition in the coronary arteries of x-irradiated, cholesterol-fed rats was significantly reduced by the oral administration of chondroitin sul-fate A at a 0.4% level in the diet. Exposure to total body x-irradiation significantly reduced the increment in liver cholesterol and liver total lipid and to a lesser extent plasma cholesterol levels induced by cholesterol feeding in the rat. No significant differences in plasma and liver cholesterol and liver cholesterol and liver total lipid levels were observed between x-irradiated, cholesterol-fed rats administered chondroitin sulfate A and x-irradiated, cholesterol-fed rats not administered this supplement.

Introduction of the Living Human Body in Freshman Gross Anatomy

Assuming that the objective of medical education is to equip the future physician with the ability to care effectively for patients, freshman gross anatomy in medical school is to be thought of as a basic discipline that will give the student an understanding of normal structure in the living human being. Although he studies and dissects cadavers in such a course, we are not attempting to make him an anatomist but, instead, we are asking him to rransfer what he learns on the cadaver to the living body. Yet, the student is usually not provided with the opportunity to apply directly to the living person what he learns in anatomy at the times he leanis it. He should be able to palpate skin, lymph nodes, muscles, tendons, bones and bony prominences, vessels, and other structures in the living human as he studies the internal anatomy and suvctural relationships in the cadaver. Whenever possible, he should see these structures studied in the cadaver move and funcdon. In this manner a solid learning bridge between anatomical knowledge and his further pursuits in physical diagnosis and clinical medicine is formed. Physical diagnosis will be more readily learned if the student has been orientated not only to the cadaver anatomy of the areas to be examined on physical examination, but also to normal living anatomy. He can then more fruitfully spend his time on such phenomena as auscultation, percussion, and pathological manifestations.

Production of Arterial Lesions by a Humoral Factor in Parabiotic Rats

The experimental production of arteriosclerosis and atherosclerosis by RES blocking agents such as colloidal carbon and thorium dioxide has implicated the RES as a factor in the etiology of these diseases. Holtzman strain male rats each received a single intravenous injection of colloidal carbon (5 mg/100 g animal body wt). Three days later the injected animals were united by parabiosis to non-injected animals of the same sex, weight and genetic strain. Carbon granules were found in the RES of injected rats, but few or no granules were found in Kupffer cells of their non-injected parabiotic partners. Coronary arteries of both injected and non-injected animals showed thickening and fragmentation of the internal elastic membrane after two months. After four to six months the lesions included degenerative changes of muscle cells just external to the internal elastic membrane and thickening of the intima. Hyperplasia of the thyroid was found in both parabionts. Addition of 1% cholesterol-5% fat to the diet caused deposition of lipid in endothelial cells and intimal macrophages of the damaged arteries of both parabionts. Distribution of lipid within the hepatic parenchymal cells was also altered in the experimental animals but not in controls. It is suggested that uptake of particulate matter by cells of the RES causes them to release a substance capable of producing arterial lesions.