Articular-epiphyseal cartilage from the femur of New Zealand rabbits was subjected to histochemistry for determination of the presence of metabolic enzymes along its zonal stratification. Glycolytic enzymes were strongly reactive in all of the zones. Krebs cycle enzymes, enzymes of the hexose monophosphate shunt and the respiratory chain enzymes showed a progressive increase in reactivity from the tangential zone through the top half of the epiphyseal zone. Indicators of lipid metabolism were fairly high in all regions of the cartilage.

The cytoplasmic granules of the blood neutrophil leukocyte of the teleost, Ictalurus punctatus, have been shown to exhibit peroxidase activity at the light and electron microscopic levels when exposed to the 3,3′-diaminobenzidine tetrahydrochloride peroxidase procedure. Erythrocytes also show activity. The addition of cyanide to the incubation medium has no apparent effect on peroxidase reactivity in neutrophils, but inhibits pseudoperoxidase reactivity in erythrocytes. The presence of peroxidase-positive granules in the neutrophil serve as a marker for identification of this cell and strongly indicate antibacterial and phagocytic functions for the neutrophil.

Using histochemical techniques, the reactivities of selected enzymes and other metabolic components were examined in the myocardium, coronary arteries, and coronary arterioles of normal, two-week-sympathectomized, and sham-operated canine hearts. There were no differences in the histochemistry of coronary arteries in any of the hearts, but important differences were noted in the myocardium and especially in the arterioles. The reactivities of the enzyme glucose-6-phosphate dehydrogenase and the nucleic acids were increased in arterioles of the sympathectomized heart, possibly indicating an increased protein synthesis. The reactivities of succinate dehydrogenase, NAD-isocitrate dehydrogenase, and cytochrome oxidase were reduced in myocardium and arterioles of sympathectomized hearts as well as in arterioles of sham-operated hearts; the changes were greater in the sympathectomized arterioles where there was also observed an increase in reactivity of lactate dehydrogenase. These findings suggest a depression in aerobic metabolic capacity and, in the case of the sympathectomized arteriole, imply a possible shift in adaptation from aerobic to anaerobic metabolism.

A histochemical study of the metabolism of rat renal arteries and arterioles. Rat renal arteries and arterioles were examined histochemically to determine their metabolic profiles. Succinate, malate and NAD-isocitrate dehydrogenase, cytochrome oxidase and ubiquinone were assessed to determine aerobic metabolism. Glucose-6-phosphate dehydrogenase and DPN diaphorase were evaluated to determine hexose-monophosphate-shunt activity. Anaerobic metabolism was evaluated via lactate dehydrogenase, and the substrate, glycogen. Gomori's lipase, beta-hydroxybutyrate dehydrogenase and amounts of neutral fat and free fatty acids were assessed as indicators of lipid utilization. Myosin ATPase activity was evaluated as an index of ATP utilization for contraction. Deoxyribonucleic and ribonucleic acids were appraised as indicators of protein synthesis. In general, the oxidative enzymes and myosin ATPase demonstrate considerable activity in renal arteries and arterioles which suggests aerobic metabolism and ATP usage. Renal arteries and arterioles also appear capable of anaerobic metabolism as indicated by strong lactate dehydrogenase reactivity and by the presence of slight to moderate quantities of glycogen, while high levels of glucose-6-phosphate dehydrogenase and moderate amounts of deoxyribonucleic acid suggest a potential for beta-hydroxybutyrate dehydrogenase, minimal lipase activity, and the absence of fatty acids with substantial amounts of neutral fat, indicate limited lipid catabolism.

Female rhesus monkeys (Macaca mulatta) received fractionated doses of orthovoltage irradiation to the submandibular and sublingual glands. Changes in the glands varied from serous cell degranulation and degeneration in the submandibular glands to acinar cell necrosis and fibrosis in the sublingual glands. Acute inflammation was absent in all irradiated glands. In all glands, the microvasculature appeared normal.