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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The direct effect of aluminum on mineralization was examined using an osteoblastlike cell line, MC3T3-E1. The mineralization process was quantitated by measuring 45Ca accumulation into the cell and matrix layer of MC3T3-E1 cells in culture. The accumulation of 45Ca into the cell and matrix layer increased dramatically after 13 days of culture without a parallel change in the DNA content of these cells. Because nodular clusters of cells appear around the same period in which a massive mineralization occurs, the marked increase in 45Ca accumulation after the 13th day of culture appears to represent deposition of 45Ca into the extracellular matrix. Thus, this culture system offers a useful model for making a quantitative estimation of osteoblast-mediated mineralization in vitro. When aluminum was added to this system, the accumulation of 45Ca into the cell matrix layer was inhibited in a dose-dependent manner: 10(-6) M aluminum reduced 45Ca accumulation to 40.8 +/- 2.7% of that in nontreated cells without affecting alkaline phosphatase activity or the DNA content of these cells. Because the concentration of aluminum used in this study is well within the range of serum aluminum levels seen in chronic dialysis patients, the direct effects of aluminum on osteoblast-mediated mineralization shown in the present study may underlie the development of so-called aluminum-induced "osteomalacia" in certain dialysis patients.
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PMID:Inhibition of in vitro mineralization by aluminum in a clonal osteoblastlike cell line, MC3T3-E1. 310 22

Cholestasis is a common complication of total parenteral nutrition (TPN) in infants. A contributing factor to the hepatic dysfunction may be a contaminant of the TPN solution, such as aluminum, that accumulates in liver and may act as a hepatotoxin. To study the hepatic effects of aluminum, growing piglets were given daily intravenous injections of aluminum, 1.5 mg/kg, for 50 days; pair-fed controls were given heparinized saline. At sacrifice, liver and serum were obtained. Liver was analyzed for histopathology and for aluminum content and localization. The hepatocyte lysosomes of the experimental group showed aluminum peaks by x-ray microanalysis, whereas the control group did not. No differences in ultrastructure were noted between the two groups when examined by electron microscopy. Mean serum total bile acid levels (27.8 +/- 15.9 SD vs 6.3 +/- 1.5 mumol/liter, p less than 0.05), mean alkaline phosphatase (309 +/- 108 vs 180 +/- 27 IU/liter, p = NS), and mean hepatic copper content (24.8 +/- 4.5 vs 14.4 +/- micrograms/g dry weight, p less than 0.01), were elevated in the aluminum-loaded piglets, indicating that cholestasis may have been produced. Also, a small but significant reduction in serum levels of 25 hydroxy-vitamin D was found in the aluminum-loaded piglets, suggesting that vitamin D hydroxylation may be impaired. Inasmuch as lysosomal contents are excreted into the bile, aluminum accumulation in lysosomes may alter lysosomal function and possibly affect bile flow or content.
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PMID:Hepatic abnormalities associated with aluminum loading in piglets. 311 Apr 47

The efficacy and safety of calcium carbonate as a phosphate binder was evaluated in 20 patients on chronic hemodialysis who had previously received aluminum hydroxide. During the control period the patients were on aluminum hydroxide and calcitriol therapy and had plasma phosphorus levels less than 6 mg/dL (4.95 +/- 0.8 mg/dL). Aluminum hydroxide was then discontinued and no phosphate binder was prescribed for 1 month. Every patient developed hyperphosphatemia so that calcium carbonate treatment was begun and calcitriol dose was adjusted in relation to plasma calcium changes. After 24 months of calcium carbonate therapy, plasma phosphorus was 4.85 +/- 0.7 mg/dL, using a daily dose of calcium carbonate of 2.57 +/- 1.3 g (range, 1 to 6 g). The daily dose per patient of calcitriol was not different from that prescribed during the control period, but in five patients calcitriol was permanently withdrawn for hypercalcemia. At the end of the study plasma calcium, magnesium, bicarbonate, alkaline phosphatase, and parathyroid hormone values were unchanged in comparison with the control period, whereas a significant reduction in plasma aluminum and plasma aluminum increase induced by deferoxamine infusion was observed. The frequency of hypercalcemic and hyperphosphatemic episodes during the last 12 months of calcium carbonate therapy (6.2% and 16.6%, respectively) was not different from that observed during the 12 months on aluminum hydroxide therapy preceding the control period (4.5% and 14.7%, respectively). It was concluded that calcium carbonate is effective in the control of hyperphosphatemia and secondary hyperparathyroidism in patients on chronic hemodialysis and that the incidence of hypercalcemia is low when the daily dosage is less than 6 g.
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PMID:Efficacy and safety of long-term treatment with calcium carbonate as a phosphate binder. 314 60

To control hyperphosphataemia without hyperaluminaemia, A1(OH)3, which was given in addition to high doses of oral calcium, was replaced by Mg(OH)2 for 6 months in 20 haemodialysed patients and for 20 months in 12. The treatment during the control period was 110 +/- 91 mmol/day of oral calcium element given as CaCO3 and/or Calcium Sorbisterit and 1.05 +/- 1.47 g/day of A1(OH)3. Haemodialysis treatment was 4 h, thrice weekly. To prevent hypermagnesaemia, dialysate magnesium was decreased from 0.75 mmol/l to 0.375 mmol/l. After a control period of 3 months, Mg(OH)2 was given at a mean dose of 2.6 +/- 2 g/day and oral calcium supplements were decreased to 76 mmol/day. Two subsequent bone histomorphometry studies were performed at 8 month intervals in four patients and at 20 month intervals in seven patients. The results show a good control of plasma calcium (mean +/- SD: 2.43 +/- 0.1 mumol/l); phosphate (1.76 +/- 0.4 to 1.66 +/- 0.3 mmol/l); aluminum (1.3 +/- 0.1 mumol/l to 0.6 +/- 0.1 mumol/l); alkaline phosphatase (135 +/- 65 to 125 +/- 40 IU); and PTH fragments (PTH C terminal decreased from 260 +/- 214 to 185 +/- 182 pg/ml, PTH medium from 4185 +/- 5113 to 2270 +/- 4880 pg/ml). Plasma magnesium increased from 0.96 +/- 0.2 to 1.54 +/- 0.2 mmol/l. Bone histomorphometry shows no change in mineralisation, and a borderline decrease of resorption parameters. The main side-effects are (1) diarrhoea, which was well controlled by transient treatment with karaya gum, and (2) an increased need for potassium binders.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Magnesium hydroxide as a complementary aluminium-free phosphate binder to moderate doses of oral calcium in uraemic patients on chronic haemodialysis: lack of deleterious effect on bone mineralisation. 314 23

A new culture system was developed to clarify the biocompatibility of implant materials with bone tissue using the MC3T3-E1 osteogenic cell line. The cells were inoculated onto specimens such as aluminium oxide, titanium, dental casting silver-palladium alloy (PD), and a plastic coverslip. To study the effects of these materials on cell growth, differentiation, and calcification, DNA and protein content, alkaline phosphatase activity, and calcium content, respectively, were determined. The results from biochemical analysis suggest titanium and aluminum oxide to have adequate biocompatibility, while PD has an irritant effect on cell metabolism. It is clear that an objective view of the differentiation and calcification processes of osteogenic cells can be understood through such analysis. From the results of this study, our culture system appears suitable for evaluating the biocompatibility of implant materials with bone tissue.
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PMID:Development of a new system for evaluating the biocompatibility of implant materials using an osteogenic cell line (MC3T3-E1). 316 81

Calcium citrate was evaluated as a dietary phosphate binder in 81 patients with end-stage renal disease. These patients were grouped as follows: Group 1, 43 patients who were treated with calcium citrate; and Group 2 (the control group), 38 patients who were treated with aluminum-containing compounds. Blood chemistries were measured monthly and medications adjusted to maintain the following levels: serum calcium, greater than 9 mg/dl; serum phosphorus, less than 5.5 mg/dl; and total CO2 content, greater than 22 mmol/liter. At the end of the treatment period, the following serum values were obtained in Groups 1 and 2, respectively: calcium, 9.6 +/- 1.2 mg/dl (mean +/- SD) versus 8.9 +/- 0.8 mg/dl (P less than 0.001); phosphorus 5.5 +/- 1.9 mg/dl versus 7.0 +/- 2.3 mg/dl (P less than 0.005); and calcium-phosphate product, 52 +/- 18 versus 61 +/- 21 (P less than 0.05). Differences in alkaline phosphatase, total CO2 content, and C-terminal parathyroid hormone (C-PTH) values were not statistically significant between the two groups. Fifteen patients in Group 1 were then switched to aluminum-containing compounds and chemistries were compared one month later. During calcium citrate therapy, serum calcium was significantly higher, while C-PTH and serum alkaline phosphatase were significantly reduced. No difference was noted in serum phosphorous and total CO2 content. A questionnaire completed by 17 patients in Group 1 documented excellent patient tolerance to calcium citrate. Hypercalcemia (greater than 10.5 mg/dl) was the only significant complication, but only one patient became symptomatic. We conclude that, as a phosphate binder, calcium citrate is at least as effective as aluminum-containing compounds.
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PMID:Calcium citrate, a nonaluminum-containing phosphate-binding agent for treatment of CRF. 328 Aug 55

Bone disease related to aluminum toxicity (aluminum-related bone disease) presents with variable clinical and biochemical findings in patients with renal failure. Bone pain and muscle weakness are common, although afflicted patients can be asymptomatic. Bone pain can be generalized or localized to the hips, back, feet, or ankles; proximal muscle weakness is common. Most cases in the United States arise from the ingestion of aluminum-containing gels by patients on long-term dialysis treatment. Patients at increased risk for developing aluminum-related bone disease include those with earlier parathyroidectomy, failed renal transplant, previous bilateral nephrectomy, and diabetes mellitus. Biochemical features that are common with aluminum-related bone disease include plasma aluminum levels greater than 100 to 150 micrograms/L, serum parathyroid hormone (PTH) levels equal to or lower than those in dialysis patients without bone disease, and normal or slightly elevated serum calcium levels. Plasma alkaline phosphatase levels are often elevated. In our experience, microcytic anemia has been uncommon. An increase in plasma aluminum levels greater than 200 micrograms/L 24 to 48 hours after the infusion of the chelating agent deferoxamine (DFO) correlates with an increased bone aluminum content, and an increment greater than 400 micrograms/L suggests marked aluminum accumulation. Radiographs are usually nonspecific. When results from indirect diagnostic procedures are equivocal, a bone biopsy is necessary. After a diagnosis of aluminum-related bone disease is established, therapy with DFO may be useful. DFO increases both the total plasma aluminum level and its ultrafilterable fraction. After an infusion of DFO, the removal of aluminum increases from 50 to 300 micrograms to 4 to 8 mg per dialysis session. Aluminum removal is similar during continuous ambulatory peritoneal dialysis after either intravenous (IV) or intraperitoneal (IP) administration of DFO. Usually, 2 to 4 g of DFO is administered once weekly, but the optimal dose and duration of therapy have not been determined. Symptoms usually improve after 4 to 12 weeks, and bone biopsies show improvement after treatment for 6 to 12 months. Further experience with DFO is needed, both to identify the optimal dosage and to clarify the risks of long-term therapy in patients with renal failure.
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PMID:Diagnosis of aluminum-related bone disease and treatment of aluminum toxicity with deferoxamine. 329 88

In order to investigate the dietary effect of calcium on aluminum-induced hypophosphatemia, five types of diet, sucrose, lactose, milk, casein and soy protein, were prepared. These diets differed with regard to Ca concentration, and carbohydrate or protein sources which were expected to modify intestinal Ca absorption. Weanling Wistar rats were fed these diets for 67 days with the addition of Al at a concentration of 2000 ppm. Nutritional constituents had little effect on Al accumulation in the duodenum and bone. Al treatments had no effects on increases of body weight. The Al treatments significantly increased duodenum alkaline phosphatase (ALPase) activity and serum phosphorus concentration in all of the dietary groups. Slight but significant decreases of bone weight were observed. There were no significant increases in serum Al concentration but bone and kidney ALPase activities were also observed. These results suggest that Al ingestion can cause hyperphosphatemia in the intact animal. Effects of Al on nutrition should be considered even if serum Al concentration does not increase.
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PMID:Increases of serum phosphorus concentration and duodenal, renal and femur alkaline phosphatase (EC 3.1.3.1) activities of normal rats fed 2000 ppm aluminum diets. 338 46

Twenty-nine patients undergoing maintenance hemodialysis were examined for dermatologic symptoms. Nineteen patients (66%) complained of pruritus, which was classified as mild (34%), moderate (24%), and severe (8%). Patients with pruritus did not differ from those without pruritus regarding serum concentrations of creatinine, urea, calcium, alkaline phosphatase or aluminum, nor was there any difference in duration of hemodialysis, age or sex. In pruritic patients serum concentrations of parathyroid hormone were significantly higher when determined with a mid-region radioimmunoassay technique (p less than 0.01) and higher, although not significantly, when the intact parathyroid hormone molecule was measured. Serum concentrations of phosphate were significantly lower in patients with pruritus (p less than 0.05).
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PMID:Pruritus in patients on maintenance hemodialysis. 341 8

Serum bone Gla-protein (S-BGP) and other serum biochemical parameters, including alkaline phosphatase (S-AP) and immunoreactive PTH (S-iPTH), were measured in 42 patients undergoing chronic hemodialysis. Each patient also had a tetracycline-labeled transiliac bone biopsy, allowing correlations between the biochemical and trabecular bone histomorphometric parameters, S-BGP was markedly increased [64.0 +/- 74.8 (+/- SD) vs. 6.2 +/- 2.2 ng/ml in normal subjects] significantly correlated with S-AP (r = 0.53) and S-iPTH (r = 0.55) levels. S-BGP was significantly higher in the 14 patients with high turnover renal osteodystrophy (HT-ROD; S-BGP, 138.5 +/- 90.8 ng/ml) than in the 28 patients with low turnover (LT-ROD; S-BGP, 26.8 +/- 14.8 ng/ml). S-BGP was significantly correlated with the cellular parameters of bone resorption and formation (r = 0.57-0.69) and with the dynamic parameters of bone formation (r = 0.62-0.82). The extent of stainable bone aluminum was significantly negatively correlated with S-BGP (r = -0.51) and serum iPTH (r = -0.33), but not with S-AP. S-BGP measurement allowed better discrimination between LT-ROD and HT-ROD groups than did S-AP measurement. However, in the patients with LT-ROD, S-BGP did not discriminate between patients with or without osteomalacia. We conclude that S-BGP is a valuable marker for evaluating bone remodeling and, more specifically, the bone formation rate at the tissue level in hemodialyzed patients.
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PMID:Serum bone Gla-protein in renal osteodystrophy: comparison with bone histomorphometry. 348 98


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