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Query: EC:3.1.3.1 (
alkaline phosphatase
)
47,916
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The localization of
3-hydroxy-3-methylglutaryl coenzyme A reductase
(HMG-CoA reductase, E.C. 1.1.1.34) in the villous and crypt cells of the small intestine was accomplished after separating these cells from the mucosal layer by sequential dissociation in a "dual-buffer" system. Consistent separation was demonstrated by using the marker enzymes
alkaline phosphatase
, specific to the villous cell, and thymidine kinase, specific to the crypt cell. Cells obtained were 95-100% viable, and no relative difference in lability was observed, as evidenced by the equal distribution of acid phosphatase. This method of cell separation was an improvement over the "scraping" technique which damaged cells severely and produced villous preparations that contained little or no reductase activity. The HMG-CoA reductase specific activity in whole cell homogenates of the ileal villi was 0.47 and of the crypts was 0.27 nmol/min per mg of protein, considerably higher values than have been reported earlier. Also in comparison to the crypts, the villi incorporated 1.5-fold more [(14)C]-acetate into sterols, a ratio similar to that describing the distribution of HMG-CoA reductase in the two cell populations. These results unequivocally establish that the villi have higher HMG-CoA reductase activity than the crypts and confirm an earlier report from this laboratory that the villi are a major site of sterol synthesis. The sterol bio-synthetic capacity of the small intestine was highest in the ileum and decreased towards the jejunum. The HMG-CoA reductase specific activity of the ileum averaged 0.30 and that of the jejunum 0.10 nmol/min per mg of protein; however, the cholesterol content of the ileum was slightly lower than the jejunum. These results are discussed to suggest the possibility that the sterol content of the ileum may largely be due to in situ synthesis.
...
PMID:3-Hydroxy-3-methylglutaryl coenzyme A reductase in isolated villous and crypt cells of the rat ileum. 92 17
The 3-years efficacy and safety of the
3-hydroxy-3-methylglutaryl coenzyme A reductase
inhibitor simvastatin (S) (previously called synvinolin or MK-733) has been studied in single and combined therapy with cholestyramine (C) in 48 hypercholesterolaemic patients. Plasma lipids, lipoproteins and apolipoproteins A-I and B, and blood safety tests (haematology, liver function, creatine phosphokinase (CPK), creatinine, blood glucose and thyroid function) were determined regularly throughout the study. Extensive ophthalmological examinations with particular focus on the lens were done before initiation of therapy and at every 6 months during drug treatment. Maximal reductions of mean plasma total cholesterol concentration (34% with S; 47% with S + C) and low-density lipoprotein (LDL)-cholesterol concentration (42% with S; 56% with S + C) were achieved after 4 weeks on full-dose therapy. During continued treatment, years 1 through 3, the reduction of mean plasma total cholesterol was 26-29% with S alone, and 31-41% with S + C. Significant reductions of plasma triglycerides (15-27%) and very low density lipoprotein (VLDL) triglycerides (10-27%) were achieved in the group treated with S as single therapy. In this group there was also a significant increase (10-14%) of high-density lipoprotein (HDL)-cholesterol. In liver aspartate (AST) and alanine (ALT) aminotransferases, as well as
alkaline phosphatase
(
ALP
), minor and variable, but usually transient, increases were seen. Repeated ophthalmological examinations did not demonstrate any drug-related side effects. It is concluded that simvastatin is a safe and efficient cholesterol-lowering drug for long-term therapy, both as a single drug and in combination with cholestyramine.
...
PMID:Long-term efficacy and safety of simvastatin alone and in combination therapy in treatment of hypercholesterolaemia. 178 13
The efficacy and safety of 20 mg simvastatin (a
3-hydroxy-3-methylglutaryl coenzyme A reductase
inhibitor) and of 16 g cholestyramine daily in the treatment of 34 hypercholesterolaemic patients have been compared after dietary treatment and stratified randomization. The effect of combined treatment with the two drugs was studied in 5 patients with severe hypercholesterolaemia. After 6 weeks of treatment the simvastatin group showed a significantly greater (p less than 0.05) decrease in the mean total plasma cholesterol concentration from 7.88 to 5.48 mmol/l than in the cholestyramine group in whom there was a fall from 7.82 to 6.73 mmol/l. Simvastatin decreased the mean plasma LDL cholesterol concentration from 6.07 to 3.76 mml/l and cholestyramine decreased it from 6.16 to 4.46 mmol/l. Simvastatin also reduced the mean plasma total triglycerides by 24%, VLDL triglycerides by 20% and VLDL cholesterol by 36%, while cholestyramine led to increases in these parameters by 64%, 85% and 63%, respectively. Mean plasma HDL cholesterol concentration and the subfractions HDL2 and HDL3 cholesterol were significantly increased by simvastatin. Simvastatin and cholestyramine reduced the mean plasma apolipoprotein B concentration by 28% and 13%, respectively. The mean plasma apolipoprotein A-I concentration was significantly higher only on simvastatin treatment. Simvastatin did not cause any subjective or objective side effects, while cholestyramine caused gastrointestinal problems in 31% of patients. Small increases in serum alanine aminotransferase (S-ALT) activity were seen with both drugs. Cholestyramine significantly raised the serum
alkaline phosphatase
(S-ALP) although to a level still within the normal range. It is concluded that 20 mg simvastatin was more effective than 16 g cholestyramine in the treatment of hypercholesterolaemia.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Comparative effects of simvastatin and cholestyramine in treatment of patients with hypercholesterolaemia. 250 17
Alkaline phosphatase (
EC 3.1.3.1
) activity in bovine aortic endothelial cells in culture was stimulated in a synergistic manner by 10(-6) M retinol and by 10(-7) M dexamethasone. An early exposure to retinol was required for maximum stimulation and could be reproduced by the addition, during growth, of 2 micrograms/ml compactin. The induced enzyme activity in cell lysates prepared from cells treated with retinol and dexamethasone had a Vmax that was 50-fold that of the controls. The stimulatory effect of retinol could be partially reversed by the addition of sonic dispersions made from cholesterol and phosphatidylcholine. The incorporation of [14C]acetate into saponifiable and non-saponifiable cellular lipids was inhibited by 10(-6) M retinol but the activities of
3-hydroxy-3-methylglutaryl coenzyme A reductase
(EC 1.1.1.34) and 3-hydroxy-3-methylglutaryl coenzyme A synthase (EC 4.1.3.5) remained unaffected. The results suggest that retinol might inhibit lipid biosynthesis through an alternate mechanism.
...
PMID:Elevation of alkaline phosphatase by retinol in bovine endothelial cells and its possible relationship to lipid biosynthesis. 286 57
Effects of CS-514, a new competitive inhibitor of
3-hydroxy-3-methylglutaryl coenzyme A reductase
, on serum lipoprotein lipid and apolipoprotein levels were studied in 13 heterozygous patients with familial hypercholesterolemia. Treatment with 10 mg of CS-514 twice daily reduced total serum cholesterol, low-density lipoprotein (LDL), and intermediate-density lipoprotein (IDL) cholesterol levels by 25%, 33%, and 33%, respectively, and increased high-density lipoprotein (HDL) cholesterol levels by 15%. Apolipoprotein B, E, and C-II levels decreased by 24%, 20%, and 19%, and apolipoproteins A-I and A-II levels increased by 10% and 7%, respectively. One patient showed abnormally high levels of SGOT, SGPT, and serum
alkaline phosphatase
, which returned to normal levels immediately after the cessation of CS-514. No other adverse effects were observed. Thus, CS-514 reduces atherogenic lipoproteins and apolipoprotein B, and increases HDL and apolipoprotein A-I and A-II, and appears to be a useful drug for heterozygous familial hypercholesterolemia.
...
PMID:Effects of CS-514 on serum lipoprotein lipid and apolipoprotein levels in patients with familial hypercholesterolemia. 310 56
We have evaluated the hypolipidemic effects of mevinolin, a competitive inhibitor of
3-hydroxy-3-methylglutaryl coenzyme A reductase
, the rate-limiting enzyme in cholesterol biosynthesis in 13 patients with heterozygous familial hypercholesterolemia (FH). Patients were maintained on a low-cholesterol diet and received sequentially increasing doses of 5, 10, 20, and 40 mg of mevinolin twice daily for a period of 1 mo on each dose. Plasma concentrations of low density lipoprotein cholesterol decreased by 19.8% on the 5 mg twice daily dose (P less than 0.05 vs. base line), 28.4% on 10 mg of mevinolin twice daily (P less than 0.05 vs. 5 mg twice daily), 35% on 20 mg of mevinolin twice daily (P less than 0.05 vs. 10 mg twice daily), and 37.7% on 40 mg of mevinolin twice daily (not statistically different from 20 mg twice daily). Concentrations of high density lipoprotein cholesterol remained stable on all doses of mevinolin whereas plasma triglyceride levels fell significantly on the 20 mg (-30.7%) and 40 mg (-34.3%) twice daily doses of mevinolin. Mevinolin was well tolerated and all patients completed the study period. Side effects during the period of study were limited to transient insomnia and headaches in two patients, transient increases in
alkaline phosphatase
in three patients, and a modest but sustained increase in
alkaline phosphatase
in a fourth patient. These results indicate that mevinolin is an effective hypolipidemic agent in patients with heterozygous FH but that the optimal doses in these patients are greater than those previously reported in normal volunteers. If long-term safety can be satisfactorily established, mevinolin offers considerable promise in the therapy of heterozygous FH.
...
PMID:Hypocholesterolemic effects of mevinolin in patients with heterozygous familial hypercholesterolemia. 656 64
The chronic toxicity of atorvastatin (AT), an inhibitor of
3-hydroxy-3-methylglutaryl coenzyme A reductase
, was evaluated in beagle dogs. Dogs were treated with 0, 10, 40, or 120 mg/kg of AT daily. Treatment lengths were 52 wk, 52 wk followed by 12 wk without drug, or 104 wk. Decreases in cholesterol levels were dose related and stable throughout the treatment period. Increases in alanine aminotransferase, aspartate aminotransferase, and
alkaline phosphatase
were transient and dose related in severity at > or = 40 mg/kg. Two dogs administered 120 mg/kg of AT daily were sacrificed moribund during the first 9 wk of treatment. Hepatic lesions were reversible with or without continued treatment and dose related in severity and distribution. Hepatic microgranulomas and hepatocellular degeneration were seen at the 120-mg/kg dose in dogs sacrificed before 53 wk. Before 53 wk, hepatocellular lipofuscin deposits were increased in dogs given > or = 40 mg/kg of AT daily but were similar to controls after 12 wk without drug and after 104 wk of continuous treatment. Bile stasis occurred in dogs given > or = 40 mg/kg of AT daily at all time points but was less severe after reversal and at week 104 compared with week 52.
...
PMID:Hepatic effects in beagle dogs administered atorvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, for 2 years. 1048 19
Animal studies, experimental models on cell lines, and epidemiological case-control studies have all suggested the possibility that
3-hydroxy-3-methylglutaryl coenzyme A reductase
inhibitors have a beneficial effect on bone metabolism. However, all epidemiological studies are not prospective in nature and based on either measurement of bone mineral density or fracture risk. They also differ in recruitment criteria, definition of statin exposure, and outcome assessment. We performed a first prospective study using specific biochemical bone markers on 17 hypercholesterolaemic non-osteoporotic subjects treated with a therapeutic dose of simvastatin 20 mg daily for 4 weeks. Our results show that serum osteocalcin concentration increased significantly (p-value < 0.05) 4 weeks after therapy, whereas other bone markers including serum bone-specific
alkaline phosphatase
activity, urine deoxypyridinoline, and urine cross-linked N-telopeptides of type I collagen did not show any significant changes. Our data support that simvastatin causes a beneficial effect on bone metabolism as reflected by an increase in serum osteocalcin concentration. This added beneficial effect of statins on bone metabolism could potentially allow statins to become the first effective anabolic agent for the treatment of osteoporosis. We urge that priority should be given to a randomised controlled study to re-evaluate this group of drugs.
...
PMID:Simvastatin increases serum osteocalcin concentration in patients treated for hypercholesterolaemia. 1154 8
A sensitive method was developed for measuring farnesyl diphosphate (FPP) accumulation in a mutant strain of Saccharomyces cerevisiae. The strain was blocked at squalene synthase (ERG9 gene) in the isoprenoid pathway and had the catalytic domain of the
3-hydroxy-3-methylglutaryl coenzyme A reductase
gene integrated into the chromosome. It required ergosterol for growth and produced E,E-farnesol. The method was based on the isolation of FPP using the anion exchanger Macro Prep High Q and conversion of FPP to E,E-farnesol with
alkaline phosphatase
. Farnesol was measured using gas chromatography-mass spectrometry. Background farnesol in the cell-free extract was also retained by the anion exchanger, but was removed with repeated washing with methanol. Both 1M NaCl and 40% (v/v) methanol were required in the elution buffer to effectively elute FPP. The preparation of cell-free extract in Bis-Tris propane/HCl, pH 7, buffer containing 0.025% (w/v) Triton X-100 and 15 mM MgCl(2) provided optimum conditions for the stabilization of FPP.
...
PMID:Detection of farnesyl diphosphate accumulation in yeast ERG9 mutants. 1275 56
Although lipid-lowering therapy with
3-hydroxy-3-methylglutaryl coenzyme A reductase
inhibitors (statins) decreases the progression of coronary artery and aortic valve calcification, the mechanism of action of these drugs to inhibit the calcification process remains unclear. In this study, we investigated the effect of statins such as cerivastatin and atorvastatin on vascular calcification by utilizing an in vitro model of inflammatory vascular calcification. Cerivastatin and atorvastatin dose-dependently inhibited in vitro calcification of human vascular smooth muscle cells (HVSMCs) induced by the following inflammatory mediators (IM): interferon-gamma, 1alpha,25-dihydroxyvitamin D3, tumor necrosis factor-alpha, and oncostatin M. These statins also depressed expression of
alkaline phosphatase
(
ALP
) in HVSMCs induced by these factors. Mevalonate and geranylgeranylpyrophosphate reversed the inhibitory effect of cerivastatin on
ALP
expression in HVSMCs, while farnesylpyrophosphate showed no effect on the
ALP
activities inhibited by this drug, suggesting that inhibition of Rho and its downstream target, Rho kinase may mediate the inhibitory effect of cerivastatin. Cerivastatin prevented RhoA activation in HVSMCs induced by the IM. A specific inhibitor of Rho kinase (Y-27632) inhibited in vitro calcification and induction of
ALP
in HVSMCs. These findings provide a possible mechanism of statins to prevent the progression of calcification in inflammatory vascular diseases such as atherosclerosis and cardiac valvular calcification.
...
PMID:Statins inhibit in vitro calcification of human vascular smooth muscle cells induced by inflammatory mediators. 1538 84
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