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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)
Plasma 25-hydroxycholecalciferol (25-H.C.C.) has been measured in 67 consective cases of fracture of the proximal femur. The values found in these patients were not different from values found in these patients were not different from those in control groups at the same time of the year. Plasma 25-H.C.C. was not correlated to plasma calcium or phosphorus, the Ca times P product, or the
alkaline phosphatase
. X-rays showed Looser zones in only 1 patient, in whom the lowest plasma 25-H.C.C. was found. Osteomalacia is not uncommon among elderly people in Denmark, but it is more likely to depend on a decline in the renal efficiency to convert 25-H.C.C. to 1,
25-dihydroxycholecalciferol
than a low dietary intake of vitamin D.
...
PMID:25-Hydroxycholecaliferol and fractures of the proximal. 5 May 9
An oral dose of 0.5 microgram of 1,
25-dihydroxycholecalciferol
(1,25-[OH]2D3) and 4 g of calcium carbonate was given daily to two dialysed patients and three undialysed patients in chronic renal failure with renal osteodystrophy. Treatment was given for 4-16 months. Intestinal calcium absorption became normal in all five patients. Plasma
alkaline phosphatase
, hydroxyproline, and immunoreactive parathyroid hormone were considerably reduced in all of the patients and in four of them these values were restored to normal. Bone histology was improved in all patients after treatment with 1,25-(OH)2D3. As well as a dramatic improvement in bone mineralisation, there was remodeling of trabecular architecture and a decrease in fibrosis in patients with initial parathyroid overactivity.
...
PMID:Long-term effects of small doses of 1,25-dihydroxycholecalciferol in renal osteodystrophy. 7 68
The pattern of response of the intestinal enzymes Ca2+-activated adenosine triphosphatase and
alkaline phosphatase
in the chick to 1,
25-dihydroxycholecalciferol
is consistent with a role for the former but not the latter enzyme in the vitamin D-dependent absorption of calcium.
...
PMID:Differentiation of the changes in alkaline phosphatase from calcium ion-activated adenosine triphosphatase activities associated with increased calcium absorption in chick intestine. 15 34
Briefly reviewed herein are some of the contemporary findings on the metabolism of vitamin D, and the biochemical and physiological effects of this steroid in the animal. Certainly the most accepted major action of vitamin D is to enhance the intestinal absorption of calcium. Historically, there is also considerable evidence that the vitamin D is required for the resorption of calcium from bone, thereby aiding in maintaining normal serum calcium levels. Increasing evidence is becoming available that vitamin D does have a direct effect at the kidney level, and that the absorption and metabolism of the phosphate ion is also significantly affected by this steroid. As a consequence of vitamin D administration to the rachitic animal, some molecular changes in the intestine have been identified and these include the induction of the vitamin D dependent calcium binding protein, an increase in intestinal levels of
alkaline phosphatase
and calcium ATPase, and a stimulation of the adenylate cyclase system. A hallmark of recent efforts is a further understanding of the metabolism of vitamin D and the formation of its most active form, 1,
25-dihydroxycholecalciferol
. All of this knowledge will prove valuable in the rational treatment of certain abnormalities of calcium and bone metabolism for which examples are already available.
...
PMID:Metabolism, function and clinical aspects of vitamin D. 16 68
Calcium and folic acid absorption were studied in 28 adult male epileptics on chronic anticonvulsant therapy. In 16 patients on diphenylhydantoin alone, calcium absorption was abnormal in 9. In 12 patients on both diphenylhydantoin and phenobarbital, calcium absorption was abnormal in 3 patients. Folic acid (3H-PGA) absorption was normal in all but one patient, while serum folate (less than 6.4 ng/ml) was reduced in all patients. Hypocalcemia (less than 8.5 mg/100 ml) occurred in only 2 patients, while serum
alkaline phosphatase
was elevated in 7 patients. These findings support the proposal that rickets and osteomalacia reported in patients on chronic anticonvulsant therapy results from reduced calcium absorption. The effect of these drugs appears to be the acceleration of the metabolism of vitamin D and an increase in the excretion of polar metabolites. This may result in reduced levels of 25-hydroxycholecalciferol and 1,
25-dihydroxycholecalciferol
which are necessary for normal absorption of calcium. Since calcium absorption may be impaired secondary to a relative vitamin D deficiency, a supplemental increase in vitamin D intake by patients on anticonvulsant drugs is recommended.
...
PMID:Calcium and folic acid absorption in patients taking anticonvulsant drugs. 17 36
The actions of 1,
25-dihydroxycholecalciferol
[1,25-(OH)2D3] and parathormone, both effective bone-resorptive agents in vivo and in vitro, were tested on CT (osteoclast-like) and PT (osteoblast-like) bone cells maintained in culture. Both agents stimulated acid phosphatase activity and hyaluronate synthesis in the CT cells and decreased
alkaline phosphatase
, citrate decarboxylation, and collagen synthesis in the PT cells. Calcitonin inhibited the changes induced in the CT but not in the PT cells. The activity of 1,25-(OH)2D3 differed from that of parathormone in one key respect: it did not increase cellular cyclic adenosine monophosphate, whereas parathormone did. Prior incubation of the bone cells with 1,25-(OH)2D3 for 6 to 24 hours made the cells refractory to the effect of parathormone on cyclic adenosine monophosphate formation. These data suggest that 1,25-(OH)2D3 and parathormone induce bone resorption by affecting the same cell types (osteoblasts and osteoclasts) although at different cellular sites.
...
PMID:1,25-dihydroxycholecalciferol and parathormone: effects on isolated osteoclast-like and osteoblast-like cells. 19 43
We conducted a 7-month randomized, single, double, single-blind comparison of calcitriol (1,25(OH)2D3) with vitamin D3 in 22 hemodialysis patients to study the effects on the biochemical abnormalities associated with osteodystrophy.
Calcitriol
was given for 3 mo. All patients had initial prestudy calcium values less than or equal to 9.5 mg/100 ml, and phosphate values less than or equal to 4.5 mg/100 ml. Data were analyzed using the Normalized Trend Index (NTI).
Calcitriol
induced a rise in calcium (8.7 to 10.25 mg/100 ml) (p less than 0.001) and a fall in
alkaline phosphatase
(p less than 0.005), while D3 had no appreciable effect. The mean dose of calcitriol during treatment was 0.579 microgram/day while that for D3 was 706 IU/day. The effect on serum phosphate concentration was variable. Hypercalcemia as high as 13.2 mg/100 ml occurred in 2 of 13 patients on 1,25(OH)2D3, but in every instance promptly returned to normal with dose reduction. No other adverse effects were noted with therapy. We conclude that calcitriol reverses the biochemical abnormalities of osteodystrophy. Since its effects are rapidly reversed with discontinuation, the drug is probably safe as well as effective.
...
PMID:Calcitriol in dialysis patients. 20 82
Calcium and vitamin D metabolism were evaluated in 5 adult epileptic patients before and during treatment with phenytoin. Significant decreases occurred in serum concentrations of calcium, albumin, and 25-hydroxy-cholecalciferol. The decreases in serum calcium paralleled those in serum albumin. Significant increases occurred in serum
alkaline phosphatase
and 1 alpha,
25-dihydroxycholecalciferol
, in urinary hydroxyproline, and in the fractional gastrointestinal absorption of calcium. Urinary cyclic adenosine monophosphate and serum parathyroid hormone did not change. The results suggest that the bone disease resulting from phenytoin therapy may be associated with a deficiency of 25-hydroxycholecalciferol and not of 1 alpha,
25-dihydroxycholecalciferol
, and that reduced gastrointestinal absorption of calcium or changes in parathyroid function may not be necessary for the development of bone disease.
...
PMID:Effect of phenytoin on bone and vitamin D metabolism. 22 Sep 3
Six long-term hemodialysis patients with progressive skeletal deterioration during long-term pharmacologic vitamin D2 therapy were treated for six to 12 months with oral 1,
25-dihydroxycholecalciferol
(1,25-(OH)2D3) to determine its therapeutic effectiveness in vitamin D2-unresponsive osteodystrophy. On bone biopsy, three of the patients had severe osteomalacia and three showed predominant osteitis fibrosa. Previous therapies, including phosphate binders and dialysis schedules, were maintained. The three patients with osteomalacia and the two with osteitis fibrosa showed clinical deterioration. There was no significant change in serum calcium, phosphate,
alkaline phosphatase
, bone densitometry, immunoreactive parathyroid hormone levels or bone histology. Roentgenograms showed multiple new fractures of ribs and femoral necks in the patients with osteomalacia and increased bone resorption in two of three patients with osteitis fibrosa. 1,25-(OH)2D3 dosage had to be decreased in all patients because of hypercalcemia with a mean tolerated dose of 0.22 microgram/day. In these patients, 1,25-(OH)2D3 was not effective therapy for progressive osteodystrophy unresponsive to pharmacologic vitamin D2.
...
PMID:Experience with 1,25-dihydroxycholecalciferol therapy in undergoing hemodialysis patients with progressive vitamin D2-treated osteodystrophy. 38 92
Fractional intestinal 47Ca calcium absorption (alpha) in 12 epileptic outpatients receiving chronic high-dose anticonvulsant therapy was reduced (p less than 0.05) compared to 12 matched normal controls. Six of the epileptics were treated orally with 0.5 microgram of 1,
25-dihydroxycholecalciferol
(1,25-DHCC) per day and six with 10 microgram of 25-hydroxycholecalciferol (25-HCC) per day for 10 days. The alpha was determined before and after treatment and compared with the effect of 0.5 microgram of 1,25-DHCC per day given for 10 days to 6 controls. An increase of the same order in alpha was found in all groups (p less than 0.05). No changes were observed in the serum levels of calcium, phosphorus,
alkaline phosphatase
or iPTH during treatment. Urinary calcium excretion was low in the epileptic patients and rose during treatment. The investigation demonstrates that the sensitivity of the intestine to 1,25-DHCC is normal in epileptic patients on anticonvulsant therapy and that 1,25-DHCC and 25-HCC in the given doses had an equal effect on the reduced intestinal calcium absorption.
...
PMID:Fractional intestinal calcium absorption in epileptics on anticonvulsant therapy. Short-term effect of 1,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol. 44 80
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