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I Edes

Publications and source records attributed to I Edes.

42 records · Page 3Linked to original sources
PubMed1983

Enzyme activity changes in rat heart after chronic alcohol ingestion.

The effect of a chronic intake of dietary alcohol upon myocardial enzymes was studied in rats. Alcohol, comprising more than 40% of the dietary calorie content, was administered to rats for 6 or 12 weeks. To assess the metabolic changes in the myocardium, the following enzymes were measured: lactate dehydrogenase (LDH), malate dehydrogenase (MDH), aldolase (ALD), isocitrate dehydrogenase (ICDH), creatine kinase (CK) and glutamate-pyruvate transaminase (GPT). The activity of CK was decreased (4.79 +/- 0.99 U X mg-1 protein) after 6 weeks on alcohol and was significantly different from that of the controls (5.98 +/- 1.44 U X mg-1 protein). After 12 weeks the CK activity of alcoholic rats had recovered to 5.99 +/- 1.08 U X mg protein-1 and approached the value found in the normal myocardium. A pronounced decrease was found in the activity of MDH: 8.26 +/- 0.69 U X mg protein-1 in the controls, and 6.78 +/- 1.07 U X mg protein-1 and 5.79 +/- 0.85 U X mg protein-1 in the alcoholic rats after 6 and 12 weeks, respectively. The LDH activity decreased to a lesser extent, but significantly: 2.45 +/- 0.18 U X mg protein-1 in the controls, and 2.11 +/- 0.07 U X mg protein-1 and 2.06 +/- 0.29 U X mg protein-1 after 6 and 12 weeks on test. Only slight, not significant, changes were observed for the other enzymes investigated (ICDH, ALD, GPT).(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine Transaminase↗
PubMed1980

Changes in the aerobic and anaerobic metabolism of skeletal muscle subjected to plaster cast immobilization.

The effect of immobilization for different periods (7, 14, 28 and 42 days) on the aerobic and anaerobic metabolism of rabbit muscles with different functions was studied by measuring the total activity of LDH and MDH as well as the distribution of their isoenzymes. The results showed that on plaster casting the characteristic aerobic metabolism of m. soleus declined with a concomitant increase in glycolytic processes. In m. gastrocnemius the anaerobic metabolism of the muscle was relatively decreased on immobilization, but glycolysis remained the prevailing energy yielding process. On immobilization the metabolism of m. soleus and that of m. gastrocnemius approached each other. This may indicate a certain dedifferentiation of the muscle tissue.

Aerobiosis↗
PubMedDate not supplied

Characterization of cytoplasmic and membrane-associated phosphatidylinositol 4,5-biphosphate phospholipase C activities in guinea pig ventricles.

The phosphoinositide-specific phospholipase C (PLC) activity present in the soluble and sarcolemmal enriched membrane fraction from guinea pig hearts was characterized using phosphatidyl [3H]inositol 4,5-biphosphate (PIP2) or phosphatidyl [3H]inositol 4-monophosphate (PIP) as substrates. The PLC activities (cytosolic and membrane associated) were specific for polyphosphoinositides (PIP2 and PIP) since no other phospholipids were hydrolyzed at pH 7.0 under various ionic conditions. Both enzymic activities were Ca2(+)-dependent (half maximal activities were achieved around pCa 5.0). The pH, detergent (deoxycholate), divalent (Ca2+ and Mg2+), and monovalent (Na+ and K+) cation dependencies were very similar between the cytosolic and membrane-associated enzyme activities, using either PIP2 or PIP as substrate. Hydrolysis of the polyphosphoinositides was inhibited in the presence of phosphatidylethanolamine, phosphatidylserine, or phosphatidylcholine. Under optimal conditions (pH 7.0, 1 mM Ca2+, 2.5 mM Mg2+, 100 mM Na+ and 0.07% deoxycholate) the specific activities of the cytosolic and membrane-associated enzymes were 19.9 +/- 0.9 and 10.1 +/- 0.9 nmol/min/mg protein, respectively, using PIP2 as substrate. Under the same conditions these activities were 18.1 +/- 1.0 and 8.0 +/- 0.8 nmol/min/mg protein for the cytosolic and membrane fractions, respectively, using PIP as substrate. Based on the similarity of the characteristics of these two PLC enzyme activities, it is suggested that the cytosolic and membrane-associated enzyme forms may be closely related.

Animals↗
PubMedDate not supplied

Alcohol-induced congestive cardiomyopathy in adult turkeys: effects on myocardial antioxidant defence systems.

The effects of chronic intake of dietary alcohol upon left ventricular function, activities of myocardial antioxidant enzymes, reduced glutathione (GSH) content and lipoperoxidation (measured as the formation of diene conjugates and lipid-soluble fluorescence) were studied in adult domestic Nicholas turkeys. The non-invasive evaluation of left ventricular function by echocardiography revealed an impaired contractile function (the calculated fractional shortening values were 31.1 +/- 4.1% in the alcoholic group and 38.8 +/- 4.4% in the controls) and dilatation of the heart in the alcoholic birds. The changes in the non-invasive parameters of the left ventricle indicate that the adult Nicholas turkey developed congestive cardiomyopathy secondary to the ingestion of ethanol. In the hearts of normal adult turkeys, high GSH content (2.39 +/- 0.25 mumol/g wet weight) and superoxide dismutase activity were found, as compared to other animals, indicating the relatively higher development of antioxidant defence systems. Compared to the controls, significant increases were noted for all the antioxidant enzymes investigated (superoxide dismutase, catalase and glutathione peroxidase) and a moderately significant decrease in the GSH content was found in the left ventricle of alcoholic birds. The changes in GSH concentration and antioxidant enzyme activities might indirectly indicate some involvement of free radicals in the pathogenesis of ethanol-induced myocardial lesion. However, the levels of in vivo lipoperoxidation in the alcoholic birds did not significantly vary from those of control turkeys. Based on these findings, it appears that the reactive oxygen radicals may play a less important role in the pathogenesis of alcohol-induced cardiomyopathy in turkeys--probably due to the higher development of myocardial antioxidant defence systems.

Alcoholism↗
PubMedDate not supplied

Regulation of cardiac sarcoplasmic reticulum function by phospholamban.

Calcium fluxes across the sarcoplasmic reticulum membrane are regulated by phosphorylation of a 27,000-dalton membrane-bound protein termed phospholamban. Phospholamban is phosphorylated by three different protein kinases (cAMP-dependent, Ca2+.CAM-dependent and Ca2+.phospholipid dependent) at apparently distinct sites. Phosphorylation by each of the protein kinases increases the rates of active calcium transport by sarcoplasmic reticulum vesicles. The stimulatory effects of protein kinases on the calcium pump may be reversed by an endogenous protein phosphatase activity. The phosphoprotein phosphatase can dephosphorylate both the cAMP-dependent and the Ca2+.CAM-dependent sites of phospholamban. Phosphorylation of phospholamban also occurs in situ, in perfused beating hearts, during the peak of the inotropic response to beta-adrenergic stimulation. Reversal of the stimulatory effects is associated with dephosphorylation of phospholamban. Thus, in vivo and in vitro studies suggest that phospholamban is a regulator for the calcium pump in cardiac sarcoplasmic reticulum. The degree of phospholamban phosphorylation determined by the interaction of specific protein kinases and phosphatases may represent an important control for sarcoplasmic reticulum function and, thus, for the contraction-relaxation cycle in the myocardium. In this review, we summarize recent evidence on physical and structural properties of phospholamban, the proposed structural molecular models for this protein, and the significance of its regulatory role both in vitro and in situ.

Adenosine Triphosphatases↗