Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Early atherosclerotic lesions in human aortas less than five hours postmortem were studied by light microscopy (20 cases) and electron microscopy (10 cases), to determine the morphological and cytochemical character of calcium deposition in the lesions. Routine and multiple special stains by light microscopy demonstrated atherosclerotic (intimal) calcium to be deposited as fine grains, ring-shaped droplets or small needle-shaped crystals, and medial calcium as fine grains or ring-shaped droplets. The calcium deposits were frequently associated with the PAS-positive basal lamina surrounding smooth muscle cells. In the intimal lesions the calcium deposits were often associated with fine granular lipid, while this association was much less frequent in the media. Calcium in atherosclerotic intima was generally not closely associated with elastic fibers but in the media was often deposited along or near elastic fibers. By electron microscopy the atherosclerotic lesions were composed of many smooth muscle cells (with or without lipid droplets), newly formed elastic fibers, amorphous ground substance, a few collagen fibrils and many membrane-limited matrix vesicle-like structures, 100-700 nm diameter. Many similar vesicles were present between the elastic laminae of the media. With the potassium pyroantimonate technique for demonstrating calcium, reaction products were most concentrated within these matrix vesicles but were also present in mitochondria of smooth muscle cells, within extracellular mitochondria-like structures, in pericellular basal lamina-like material and loosely dispersed in the interstitial ground substance. All elastic fibers were negative for calcium by this technique. The membrane of the matrix vesicle-like structures were cytochemically positive for alkaline phosphatase and adenosine triphosphatase. These studies suggest that calcification in human atherosclerosis and media is related to smooth muscle cell degeneration and that the major initial loci for calcium deposition are matrix vesicles from degraded cells, comparable to osteogenic calcification of cartilage.
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PMID:Calcification in atherosclerosis. I. Human studies. 294 18

Isolation of non-esterified [14C]cholesterol bound to albumin from rat serum, 8 days after i.p. injection of [14C]cholesterol, was achieved by affinity chromatography, using Cibacron blue F3GA bound to Sepharose 4B and by Sephadex G-150 column chromatography. Both methods permit isolation of large quantities of cholesterol-loaded albumin, free of globulins and lipoproteins. The isolated albumin-cholesterol fraction was estimated to be 4.6 mg/100 ml serum, which represents approx. the 24% of the non-esterified cholesterol present in the rat serum. Albumin-cholesterol, cholesterol glucoside, cholesterol hemisuccinate and hydroxylated derivatives of cholesterol produced a biphasic curve of changes in synaptosomal plasma membranes (SPM)-bound (Na+ + K+)-stimulated ATPase activity. Low concentrations of the ligand progressively increased the enzyme activity, while increasing the ligand concentration above that which maximally stimulated the enzyme activity, produced a progressive inhibition. Lipoproteins did not have any effect on the enzyme activity. The fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene-labeled SPM, increased in albumin-cholesterol derivatives-treated SPM, which is consistent with a general decrease in membrane bilayer fluidity. The results provide evidence that the 'albumin-cholesterol' fraction of the serum may directly affect the cell membrane-bound enzyme activity.
Atherosclerosis 1986 Jul
PMID:Evidence for the existence of non-esterified cholesterol carried by albumin in rat serum. 301 57

The interest evoked by the Broad Breasted White Turkey (BBWT) as an animal model for studying the cardiovascular damages produced by hypertension and catecholamines is mainly due to the fact that hypertension is spontaneous and tissue and circulating catecholamines, especially norepinephrine, are extremely high. In this paper we focused our attention on three characteristic pathophysiological features displayed by these animals which are strictly related, as well as in humans, to the elevated blood pressure values and to catecholamine action. We also described the possibility of modifying the development of some of these lesions with pharmacological interventions liable to antagonize the peripheral effects of norepinephrine and epinephrine. The dissecting aneurysm of the aorta accounts for 5-10% of sudden deaths in this animal strain. It can be prevented by lowering blood pressure, especially with beta-blockers, and facilitated by MAO-inhibitors. The degree of cardiac hypertrophy is remarkably high and unexpectedly characterized by the synthesis of a "fast" V1-like isomyosin with high Ca++ activated ATPase activity, oxygen consumption and speed of muscle shortening. Neither the reduction of the degree of cardiac hypertrophy, nor treatment with labetalol alone were able to modify this peculiar pattern. In spite of having very high levels of high-density-lipoproteins, which are known to be protective against atherosclerosis, this animal develops a severe atheromatous disease especially in the abdominal aorta, where the cellular growth has also been proven to be in vitro more pronounced than in the thoracic tract. Treatment with beta-blockers reduced the severity and extent of the lesion even in absence of a significant reduction in blood pressure.
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PMID:Catecholamine-induced cardiovascular disease in the spontaneously hypertensive and atherosclerotic turkey. 304 59

The effect on the cardiac sarcoplasmic reticulum of an atherogenic (1% cholesterol) diet fed during the neonatal vs the juvenile period of life was studied in Yorkshire swine. Male piglets were randomly assigned at birth to 1 of 4 groups: group I (control), group II (lactation feeding), group III (juvenile period feeding) and group IV (lactation and juvenile feeding). All animals were killed at 55 weeks of age and cardiac sarcoplasmic reticulum (SR) isolated for assay of calcium uptake, Ca2+-Mg2+ ATPase activity, and lipid analysis by thin-layer chromatography and gas chromatography. The amount of cholesterol/mg SR protein and the cholesterol/phospholipid ratio were higher in the animals fed during lactation (groups II and IV) and lower in those fed only during the juvenile period (group III). Phospholipid fatty acid patterns as measured by gas chromatography were unaltered in any group. Calcium uptake was markedly diminished in all experimental conditions: group II 47%, group III 65% and group IV 96%. Compared to the observed changes in calcium transport, the ATP hydrolytic activity was relatively less affected. Only in group IV a significant decrease (41%) was seen. Groups II and III show no change in ATP hydrolytic activity. The decrease in calcium uptake and altered cholesterol/phospholipid ratio without effect on ATP hydrolytic activity is consistent with an uncoupling of calcium transport related to the atherogenic diet in early life.
Atherosclerosis 1985 Apr
PMID:Cardiac sarcoplasmic reticulum. Effects of an atherogenic diet during the neonatal and juvenile period. 315 93

For comparison with our previous study on early calcification in human atherosclerosis, the aortas of rabbits and chickens with experimentally induced atherosclerosis were studied by gross examination, light microscopy and electron microscopy, including various cytochemical techniques. Nine male New Zealand white rabbits and nine male white leghorn chickens were fed an atherogenic diet of chow with 8% peanut oil and 2% cholesterol for one, two or three months. Six rabbits and six chickens, fed normal chow for one, two or three months, served as controls. The normal diet chickens were found to have lipid-negative spontaneous fibrous plaques in the abdominal aorta, which following atherogenic diet developed lipid deposition and increasing calcium deposition. The normal diet rabbits had no aortic lesions, but following an atherogenic diet developed highly lipid-positive foam cell intimal lesions which subsequently developed increasing amounts of smooth muscle cells and calcium. Ultrastructurally, the aortic plaques in normal diet chickens were composed of smooth muscle cells, collagen, elastic fibers, ground substance and a few small extracellular matrix vesicles bounded by a trilaminar membrane. In the atherogenic diet chickens, these vesicles increased in number as did their staining for calcium by the pyroantimonate technique. The membranes of vesicles were cytochemically positive for alkaline phosphatase and adenosine triphosphatase. Similar matrix vesicles were present in the interstitium of the media. In both intima and media, the vesicles appeared to be largely derived from degenerating smooth muscle cells. The aortas of atherogenic diet rabbits were similar to the chickens except for many more lipid-laden foam cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Calcification in atherosclerosis. II. Animal studies. 378 82

The biochemical and functional changes associated with ligation (40 min) of the left circumflex coronary artery and subsequent reperfusion (60 min) in the rabbit made diabetic with alloxan were studied and compared with those of control animals. Measurement of haemodynamic parameters revealed that both left ventricular pressure and mean arterial pressure were significantly (P less than 0.05) decreased after ligation and reperfusion in the diabetic animals compared with controls. Analysis of subcellular organelle enzyme markers from the ischaemic tissue revealed that sarcolemmal Na+,K+-ATPase, mitochondrial ATPase and sarcoplasmic reticulum ATPase activities were decreased after ligation to the same extent in the diabetic and control animals. However, upon reperfusion, the recovery of mitochondrial ATPase activity was significantly (P less than 0.05) less in the diabetic animals than in the controls. Ion measurements revealed a significant (P less than 0.05) depletion of Mg in diabetic hearts before ligation, and this was augmented during reperfusion. In contrast, a significantly (P less than 0.05) higher calcium accumulation was observed upon reperfusion in the hearts of diabetic animals. Similarly, both tissue ATP levels and the ability of the mitochondria to generate ATP were depressed to a greater degree in the diabetic animals. Our results indicate, therefore, a greater susceptibility of the diabetic myocardium to ischaemic/reperfusion injury which in the clinical situation would exacerbate the problems associated with atherosclerosis and possibly contribute to the high mortality from cardiovascular complications in diabetic patients.
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PMID:Coronary artery ligation and reperfusion in rabbits made diabetic with alloxan. 381 32

A light microscopy study on the localization of enzyme activity within atherosclerotic human intracranial arteries was performed on autopsy material obtained within 4 hours of death. The data suggests that the atherosclerotic process first goes through a proliferative phase and then a degenerative phase culminating in the formation of a plaque. In the proliferative phase, smooth muscle cell proliferation has formed a thickened intima. Tetrazolium reductase, adenosine triphosphatase (ATPase) and adenosine monophosphatase (AMPase) activities are present in these cells, while all dehydrogenases and acid phosphatase activities were weak or not present. As the degenerative phase commences, an area of necrosis, lipid and macrophage accumulation is formed on the lumen side of the elastica. This area increases in size until a plaque is formed. Unsaturated polar and nonpolar lipid, cholesterol, alpha-glycerophosphate dehydrogenase, acid phosphatase, and AMPase activities are associated with these areas and in foam cells, which are often found in the thickened intima of the proliferative phase. Tetrazolium reductase and ATPase activities decrease in the thickened intima as the area of necrosis increases in size, while dehydrogenase activity, except that for alpha-glycerophosphate, remains low or not present. Patterns of enzyme alterations for various stages of the disease process in intracranial arteries, the aorta and coronary arteries suggest a similar, if not identical, progression of the atherosclerotic process, irrespective of known differences in the prevalence of atherosclerosis.
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PMID:A histoenzymatic study of human intracranial atherosclerosis. 426 Jul 21

In order to study the influence of the cholesterol content on the calcium entry channel, the human red blood cell was used as a model system. The cholesterol to lecithin ratio (C/L ratio) of the membrane was modified experimentally by incubating the cells (15h, 25 degrees) with liposomes of defined C/L ratios. Subsequently, net 45Calcium-influx into the cell was measured by inhibiting the Ca-ejecting ATPase with vanadate. Additionally, the use of nitrendipine, a potent calcium channel inhibitor, during incubation allowed the determination of Ca-influx through the calcium channel. A positive correlation between the 45Ca++-influx and the molar C/L ratio of the membrane was found over a wide C/L range. A molar C/L ratio of 1.4 in the membrane increased calcium influx by 150 % compared to controls (molar C/L ratio = 0.8, calcium influx rate = 100 %), while a molar C/L ratio at less than 0.75 decreased calcium influx by 50 %. We conclude, that the cholesterol content of the membrane greatly influences the calcium channel and thus plays a pivotal role for the availability of calcium as a second messenger. These findings may provide a link between high plasma cholesterol and the development of atherosclerosis as well as enhanced platelet aggregability.
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PMID:The cholesterol content of the human erythrocyte influences calcium influx through the channel. 609 23

Diabetes mellitus causes congestive heart failure in humans, independent of atherosclerosis. The present study extends previous work on the reversibility, with insulin, of the alterations in myocardial function and contractile protein biochemistry observed in diabetic rats. The response of these alterations to different fixed doses of insulin was explored. Diabetic rats were given 0, 0.5, 1, 1.5, 2, or 2.5 U of insulin daily for 6 wk. Papillary muscle function, actomyosin ATPase, and myosin isoenzyme distribution showed progressive normalization with increasing insulin dose as blood glucose concentration returned to normal. Thus insulin therapy in diabetic rats on a normal diet produces continuous improvement in cardiac function and biochemistry as euglycemia is approached. This study also suggests that mild diabetes results in qualitatively identical, although quantitatively less pronounced, myocardial changes compared with those observed in severely diabetic rats.
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PMID:Diabetic cardiomyopathy in rats: mechanical and biochemical response to different insulin doses. 623 41

Structural and functional characteristics of erythrocyte membranes were studied in rabbits with experimental atherosclerosis. In animals with single lipid spots in the aorta, a significant rise of the plasma cholesterol level was associated with the increased cholesterol/phospholipid (CS/PL) ratio and diminished activity of erythrocyte membrane Na+, K+-ATPase. EPMR spin probe data point to changes in structural membrane characteristics--an increase in order parameter for fatty acid chains of lipids and expansion of the temperature interval of the transition phase in the membranes. In rabbits with total aorta injury, a further increase both in the plasma cholesterol concentration and in the CS/PL ratio as well as in structural changes in erythrocyte membranes does not lead to another decrease in the enzymatic activity. In aorta homogenates of the experimental animals, the activity of Na+, K+-ATPase correlated with that in the erythrocyte membrane. This suggests the existence of similar chemical and structural changes in aorta cell membranes. The data may provide an indirect evidence in favour of the hypothesis of the involvement of smooth muscle cells and membrane enzymatic activity alterations in atherosclerosis.
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PMID:[Structural and functional changes in erythrocyte membranes in experimental atherosclerosis]. 624 22


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