Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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

We measured the interrelationships between ventricular muscle myosin mass, myosin ATPase activity and collagen in cats with varying degrees of hypertrophy from left ventricular (LV) pressure-overload produced by either aortic banding or renal hypertension. In order to compare two models of LV pressure-overload with different time courses of progression, the results were analyzed as a function of LV mass or LV weight/body weight (LV/BW) ratio. Myosin was quantitated by SDS-polyacrylamide gel electrophoresis and hydroxyproline was measured as an index of collagen. Myosin concentration was positively correlated with increasing LV mass in control cats. However, in pressure-overloaded LV, myosin concentration was elevated and nearly constant for LV less than 9.0 g, but decreased in LV greater than 9.0 g. Myosin concentration in pressure-overloaded LV was greatest before a significant increase in LV/BW ratio. Hydroxyproline concentration was inversely related to myosin concentration in both LV pressure-overload models and increased with the severity of hypertrophy. Actomyosin ATPase activity in pressure-overloaded LV, was not significantly different from control over a wide range of LV/BW ratios. However, absolute myosin ATP hydrolysis in pressure-overloaded LV, increased by as much as 40%, relative to control, due primarily to increased myosin. The changing spectrum and interrelationships of myosin and collagen were independent of the mechanism of pressure-overload, but were correlated with the severity of hypertrophy.
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PMID:Myocardial changes during the progression of left ventricular pressure-overload by renal hypertension or aortic constriction: myosin, myosin ATPase and collagen. 295 26

The effects of aldosterone on transepithelial sodium transport (measured by the short-circuit current (SCC) and on Na+-K+-adenosine triphosphatase (ATPase) biogenesis have been studied in A6 kidney cells grown on collagen-coated filters in two different media. In medium A, base-line SCCA was close to zero but transmural electrical resistance (RA) was high. Aldosterone (100 nM, t24h) drastically increased SCCA and RA, but only after a 4-h latent period. In medium B, base-line SCCB and RB were significantly higher than in medium A. Aldosterone significantly enhanced SCCB and to a lesser extent RB after a much shorter latent period (approximately 45 min) than in medium A. In medium A, aldosterone elicited a fourfold increase in the relative rate of synthesis of alpha- and beta-subunits of Na+-K+-ATPase. A twofold increase was already observed within the observed latent period. This time course suggests that de novo synthesis of sodium pumps might be one of the critical factors underlying the increase in sodium transport in this growth medium. In medium B, aldosterone elicited a two- to fourfold increase in the relative rate of synthesis of the alpha- and beta-subunits of Na+-K+-ATPase that paralleled SCCB. Thus de novo synthesis of Na+-K+-ATPase is clearly not a prerequisite for the early mineralocorticoid response (t90 min - t180 min), but still could be part of the late mineralocorticoid response (t3 h - t24 h). In both media, the immunochemical cellular pool of Na+-K+-ATPase was apparently not modulated by aldosterone for up to 48 h of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Aldosterone regulation of Na+ transport and Na+-K+-ATPase in A6 cells: role of growth conditions. 303 69

Ouabain, a digitalis glycoside and an inhibitor of the Mg2+-dependent Na+-K+ ATPase, was used to probe the role of intracellular Na+ levels in the regulation of platelet reactivity. Platelets preincubated with 10 to 150 microM ouabain exhibited a potentiated aggregation response to collagen (14.4 to 180 micrograms/mL), ADP (4 to 12 microM) and thrombin (0.03 to 0.10 unit/mL). Ouabain markedly decreased the time interval between addition of collagen and the onset of shape change. At submaximal concentrations of collagen, thrombin and ADP, preincubation with ouabain increased the rate and amplitude of the aggregation response. Irreversible aggregation was achieved in ouabain-treated platelets by using concentrations of ADP which induced only reversible aggregation in the absence of ouabain. In addition, chelation of extracellular calcium with EGTA or EDTA (2 mM) failed to block reactivity to collagen, ADP or thrombin in ouabain-treated platelets. These results suggest that ouabain induces a "preactivation state" in platelets, perhaps via modulation of intracellular Na+ levels.
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PMID:Ouabain affects platelet reactivity as measured in vitro. 311 Oct 4

Study of the products secreted by pancreatic ductal cells and analysis of the mechanisms involved in the discharge of these products have been limited by a lack of in vitro models available to experimentally approach this problem. To this aim, this investigation has been designed to determine if a human pancreatic carcinoma cell line of ductal origin (PANC-1) has maintained some of the differentiated characteristics of normal mammalian pancreatic ductal epithelium. Morphological and immunocytochemical studies indicated that, similar to isolated rat pancreatic ducts, the PANC-1 cell line contained (a) intermediate filaments of the epithelial class, (b) a basolateral plasma membrane localization of Na+, K+-ATPase, (c) complete tight junctions based on freeze-fracture analysis, (d) a cuboidal morphology when grown on Type I collagen-coated nitrocellulose filters or isolated amnion basement membrane, and (e) normal ductal epithelial ultrastructural features. Biochemical analysis indicated that, also similar to isolated rat and human pancreatic ducts, the PANC-1 cell line contained (a) gamma-glutamyltranspeptidase, (b) carbonic anhydrase, and (c) Na+, K+-ATPase based on [3H]ouabain binding assays. Comparative studies with other transformed lines indicated that PANC-1 cells have similarities to ductal lines such as MDCK cells but are markedly different from mesenchymally derived lines such as L cells. In addition, as with isolated rat and human ducts, PANC-1 cells synthesize and secrete sulfated proteins with a MW range of approximately 180K to 1 million daltons, with the predominant species being 660K daltons as indicated by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis. These results indicate that the PANC-1 cell line has maintained at least some of the differentiated characteristics of normal pancreatic ductal epithelial cells and may be a useful system for study of ductal secretory products as well as the mechanisms involved in the discharge of these products.
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PMID:Morphological and biochemical characterization of a human pancreatic ductal cell line (PANC-1). 314 17

The ability to induce alcoholic cardiomyopathy has been tested in a variety of animal species. Myocardial alterations consistent with subclinical heart disease have been produced in many of these studies through a direct effect of ethanol or its metabolites upon the heart or a neurohumoral mechanism. In the rat most studies have, however, failed to finding diminished contractility in the basal state. In long-term animals the acute left ventricular responses to isoproterenol and calcium as well as pacing were reduced. Long-term studies in mongrel dogs fed 36 per cent of calories as ethanol produced an early decrease in left ventricular diastolic compliance related to interstitial collagen accumulation. Diminished contractility developed by four years. In addition to the morphologic evidence of distorted sarcoplasmic reticulum, in vitro experiments suggest important acute effects. Each mole of ethanol is bound tightly to each mole of protein comprising the Ca-ATPase pump, which is inhibited. Impaired uptake and binding of calcium by the sarcoplasmic reticulum has been observed in chronic alcohol models at one to two day intervals following the last exposure to ethanol. In addition, the flux of calcium ion does not appear normal in terms of access to contractile protein, where the calcium regulated inhibition of the troponin interaction with myosin is impaired. Experimental studies in a canine model of alcoholism revealed that the ventricular fibrillation threshold was moderately reduced in the basal state after 18 months and was diminished further after acute exposure.
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PMID:Experimental models for studying the effects of ethanol on the myocardium. 331 64

The etiology of keratoconus is still unknown. This project was designed to study, in a group of keratoconic patients and a control group, the following: clinical, endocrinological, immunological, psychological, and ophthalmological factors. We found mean serum magnesium deficiency and type A behavior to be significantly more common in keratoconic patients than in a control group of patients. In addition changes in gluco-mineral corticoids, changes in glucose metabolism, edema of allergic origin, and genetic factors may collaborate in the development of keratoconus. All these factors could affect the osmotic mechanism of the cornea: Na-K and/or Ca ATPase, the collagen structure by alteration of the adenylate cyclase activity, and other mechanisms. This study suggests an association between keratoconus, magnesium depletion, and type A behavior, which together constitute a new clinical syndrome and confirm an association between keratoconus and atopy.
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PMID:Keratoconus, magnesium deficiency, type A behavior, and allergy. 341 70

The functions of epithelia that line small airways in mammalian lungs are unknown. To gain insight into the role of small-airway epithelia in lung liquid balance, Clara cells were isolated from excised rabbit lungs by enzymatic digestion, enriched by centrifugal elutriation and density centrifugation, and further purified by differential adherence to collagen matrices. The resulting cell population was composed of 85% Clara cells, 3% ciliated cells, and less than 1% macrophages. The remainder of the cells were not definitively identified. The transepithelial potential difference peaked on day 3 in culture. Preparations studied in Ussing flux chambers exhibited a potential difference of 8 mV (apical bath negative), a resistance of 500 ohm X cm2, and an equivalent short-circuit current (ISCeq) of 16 microA/cm2. Inhibition of the Na+/K+-ATPase by ouabain abolished ISCeq. Exposure of the apical surface to amiloride or replacement of Na+ in the apical bathing solution with an impermeant cation (N-methyl-D-glucamine) decreased ISCeq by 66% and 93%, respectively. Neither amiloride in the basolateral bathing solution, nor bumetanide, nor isoproterenol significantly altered basal ISCeq. These findings indicate that Clara cells in culture form polarized monolayers, Clara cells transport Na+ from the apical to the basolateral bathing solution, and the small airways of the rabbit may function in liquid absorption.
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PMID:Ion transport by rabbit nonciliated bronchiolar epithelial cells (Clara cells) in culture. 347 66

Age peculiarities of common structure of the microcirculatory pathways, specific volumes and amount of microvessels, zonal parameters of pericapillary microcirculation of metabolites, glycosamine glycans and glycoproteins contents, phosphatase and ATPase activity, collagen and elastic fibers of the microcirculatory bed vessels have been studied in 190 unchanged uteri, beginning from 36-week-old fetuses up to 35 years of age. The microcirculatory bed of myometrium during the period of postnatal ontogenesis investigated possesses a polymer-homonomous structural organization; its base make myoangiomas, including the terminal arteriole with precapillaries and collecting venule, that run from it. Similar structure of the myometrium microcirculatory pathways is already observed in fetuses of late antenatal period. In endometrium formed glanduloangionomas are revealed in the prepubertal age. Increase in glycosamine glycans contents is stated in the microvessel walls and in the uterine stroma during the process of its development. Compensatory-adaptive changes in the uterine microcirculatory bed are described during the newborn period up to the puberty. Functionally mature structures of the microcirculatory pathways in the submucosal and vascular layers of myometrium, endometrium and in the cervix uteri are found to be formed earlier than in other areas of the organ.
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PMID:[Development of the uterine microcirculatory bed in postnatal ontogeny]. 367 8

The present investigation was undertaken to clarify the in vitro effect of zinc on bone metabolism in tissue culture. Calvaria were removed from weanling rats (3-week-old males) and cultured for periods up to 96 hr in Dulbecco's Modified Eagle Medium (high glucose, 4500 mg/dl) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained 10(-7) to 10(-3) M zinc sulfate. All cultures were incubated at 37 degrees in 5% CO2/95% air. Zinc uptake by bone was increased significantly in cultures with concentrations of zinc greater than 10(-6) M. Bone calcium content was increased significantly by the presence of 10(-4) M zinc. This increase was blocked by the presence of 10(-6) M cycloheximide. Bone alkaline phosphatase activity was elevated in the presence of zinc (10(-6) to 10(-3) M), but the effect was inhibited by 10(-7) M cycloheximide or 10(-8) M actinomycin D. Zinc (10(-4) M) also significantly increased ATPase activity in the bone, whereas it did not alter significantly by pyrophosphatase, acid phosphatase and beta-N-acetylglucosaminidase activities. Furthermore, bone collagen content was raised by 10(-6) to 10(-4) M zinc. This elevation was prevented by 10(-7) cycloheximide or 10(-8) M actinomycin D. Bone DNA content and [3H]thymidine incorporation by the bone were not altered significantly by 10(-4) M zinc. These findings indicate that the zinc had a direct stimulatory effect on bone mineralization in vitro, and that bone protein synthesis was a necessary component of this response. Zinc may stimulate bone formation in tissue culture.
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PMID:Stimulatory effect of zinc on bone formation in tissue culture. 368 32


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