Changes in hepatocyte dehydrogenase activity in different zones of liver acini during the revascularization of ischemic extremities

After ischemia (3, 6, 9 and 12 h) of the hind extremities in dogs with a subsequent revascularization for 2 h, enzymatic activity of hepatocytes changes. After ischemia for 3 h the enzymatic activity increases. Restoration of the blood flow at later stages of the experiment results in a progressive decrease of dehydrogenase and diaphorase activities. To a greater extend the changes of the enzymatic activity are observed in perivenular hepatocytes (in the 3d zone of the hepatic acinus).     

Functional and morphological changes in the kidneys in acute embologenic arterial occlusion of the extremities

The results of biochemical, radioisotope and morphological investigations of dog kidneys in experimental acute occlusion of hind limb arteries during ischemia and in postischemic periods are reviewed. Morphological and functional changes in the kidneys occur in ischemia. Blood flow recovery in the extremities aggravates these changes leading in 12-hour ischemia to acute renal failure.     

Quantitative histophotometric study of liver dehydrogenase activity during temporary ischemia of the extremities

This prospective study depicts quantitative histophotometric characteristics of the changes in the histoenzymologic spectrum of the liver in the course of temporary ischemia of the extremities with subsequent revascularization. The increase in the activities of dehydrogenases under study in the course of a 3-hour ischemia, and the decrease of these parameters in 6- and 12-hour ischemia was discovered, that was determined as a compensatory response followed by the period of compensation exhaustion and the development of the period of complete exhaustion. The data of the study of drug correction of the postischemia syndrome confirmed the rationality of the efforts that were made. A special program developed for computer processing of histological data allows rapid adaptation of the methods for different histophotometric examinations with the use of TV analyzer of the picture, this creating wider possibilities as compared to the known analogs.     

Quantitative changes in liver dehydrogenase activity during temporary ischemia of the extremities and in the postischemic period

Experimental temporary occlusion of the dog hind limbs was produced. Histoenzymological changes in the liver induced by the temporary ischemia of the limbs and by ischemia with a 2-hour revascularization were subjected to comparative histophotometric examination. The data obtained indicate an appreciable rise in the enzymatic activity of hepatocytes at the early stages of experiments and increasing reduction in metabolic processes at the later stages. A substantial decrease was noted in the activity of the liver enzymes under study, with that decrease being especially pronounced at the later times in experiments with limb revascularization, which is accounted for by a far greater release to the bloodstream of metabolic products from the ischemized limbs.     

Electron microscopic-cytochemical heterogeneity of succinate dehydrogenase activity in rat cardiomyocytes

The ultrastructural localization of succinate dehydrogenase in white rat heart myocytes is studied and heterogeneity of reaction products in separate mitochondria and their groups is described. The enzyme activity is cardiomyocyte electron density dependent. This dependence, in all probability, is the result of different structural and functional states of cells and their organelles, that is revealed by electron microscopy as different electron density of these. It is found that middle electron density cells have the maximum enzyme activity. The mechanisms of enzyme activity dependence of cell electron density are discussed.     

Changes in the 17 beta-hydroxysteroid dehydrogenase activity of mouse blastocysts during delayed implantation

The rate of estrone (E1)----estradiol-17 beta (E2) or E2----E1 conversion catalyzed by 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity was determined for each mouse embryo in modified F-10 medium containing 0.95 microM 3H-E1 or 3H-E2. During delayed implantation, the E1----E2 conversion rate was decreased (p less than 0.005) from 5.69 +/- 0.34 fmol/h/blastocyst on Day 5 to 3.50 +/- 0.46 fmol/h/blastocyst on Day 9, whereas E2----E1 was increased (p less than 0.005) from 7.44 +/- 1.08 to 18.60 +/- 2.04 fmol/h/blastocyst. After estrogen injection, the Day 9 implanting blastocyst showed an increase (p less than 0.005) in E1----E2 conversion to 9.05 +/- 0.64 fmol/h/blastocyst but a slight, insignificant decrease in E2----E1 conversion to 14.2 +/- 1.82 fmol/h/blastocyst. A similar trend was also observed in Day 5 implanting blastocysts when compared to Day 5 delayed blastocysts. Thus, 17 beta-HSD activity in delayed blastocysts favors E2----E1 over E1----E2 conversion in a ratio of 5:1. After estrogen induction of implantation, the E1----E2 conversion rate is stimulated and the ratio of E2----E1 to E1----E2 rate is decreased to 1.5:1. The results suggest that 17 beta-HSD activity may be involved in blastocyst implantation.     

Changes in the dehydrogenase and GABA transaminase activity in the cerebral cortex during corazol kindling

The experiments on (CBA X C57BL/6)F1 mice have shown that regular corazol injections in subliminal doses stimulated seizure susceptibility (pharmacological kindling). Cytophotometric assay of the activity of oxidative metabolism enzymes (glutamate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, alpha-oxoglutarate dehydrogenase, lactate dehydrogenase) and GABA-transaminase in the sensorimotor cortex of kindled mice in post-convulsive period, and 24 hours or 30 days after corazol injections were discontinued, has revealed some specific alterations of the enzymes under study, that suggest the existence of two phases of energy metabolism disturbances. The first phase (24 hours after corazol injections were discontinued) is characterized by intensified succinic acid oxidation, while the second phase (30 days after the last injection) is characterized by anaerobic glycolysis in neuronal and glial cells. Inhibition of GABA-transaminase activity was particularly marked in postconvulsive period. From a molecular point of view these data may be considered as enzyme disturbances during stimulation of seizure susceptability or seizure activity and as a compensation component ensuring anticonvulsive mechanisms and reparative processes (antagonistic principle of molecular mechanism regulation) during activation of antiepileptic system.     

Changes in ultrastructure and actomyosin complex of cardiomyocytes in experimental hypergravitation

There were studied the cardiomyocyte ultrastructure, contractile function, actomyosin complex composition and property of the rat ventricular myocardium after repeated gravitational overloading and following rest. In the hypergravitation period cardiomyocyte changes carry destructive character or are regenerative processes manifestation. They are comparable with myocardial contractile function state and with displacements in molecular structure of myofibrillar apparatus. At rest conditions the liquidation of cardiomyocytes destructive changes falls behind the normalization of contractile and regulatory cells of physico-chemical characteristics. The possible reasons of this phenomenon are discussed.     

Changes in NADPH-diaphorase activity in the rat dorsal horn following an acute experimental myositis

Previous neurophysiological experiments have shown that in rats with an acute myositis of the gastrocnemius-soleus muscle, dorsal horn neurones exhibit an increase in responsiveness to peripheral stimulation and in background activity. The present study investigated the possible correlation between changes in NADPH-diaphorase activity and neurophysiological alterations. In the animals used for the electrophysiological experiments the diaphorase activity in sections of the lumbar spinal cord was determined with the NADPH-nitroblue tetrazolium reaction. The main finding was a massive reduction in the number of diaphorase-positive cells in the superficial dorsal horn in animals with a myositis. The staining intensity in the remaining neurones was unchanged. The results are interpreted as indicating that the myositis in addition to the surgical operations represents a supramaximal input to the dorsal horn causing neurotoxic effects in diaphorase- positive neurones.     

Glutamate dehydrogenase activity in the pancreatic tissue in acute experimental pancreatitis and under the action of sodium thiosulphate

It has been established that the development of acute pancreatitis is accompanied by the reduced activity of glutamate dehydrogenase in the mitochondrial fraction of pancreas, pronounced in the focus of tissue necrosis and less expressed in the reactive inflammation focus. Besides this in the pancreas redistribution of enzyme, activity in the subcellular organelles takes place and enzyme activity emerges in the cytosol and further--in the blood and peritoneum liquid. Sodium thiosulfate has a marked correlation effect.