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)

Osteomalacia is characterized by large osteoid seams and a preserved volume of bone trabeculae. The mineralization of newly formed bone requires adequate concentrations of calcium and phosphate: the Ca.P product has been regarded as a useful, empirical diagnostic test of osteomalacia. It decreases in patients with osteomalacia mainly because they have very low plasma phosphate levels. At present total body bone mineral and total body bone density can be directly measured by whole body absorptiometry, which indicates the lowest total mineral content of the skeleton which can increase quickly after adequate treatment. The main symptoms of osteomalacia are: bone pain; muscular weakness (commonly as pelvic girdle myopathy); Looser-Milkman pseudofractures or more often a pattern of generalized demineralization at X-ray. The main biochemical parameters in osteomalacia include: defective calcium absorption with hypocalcemia and hypocalciuria; defective intestinal phosphate absorption with hypophosphatemia; there is often increased renal phosphate clearance due to hypocalcemia and secondary hyperparathyroidism; elevated alkaline phosphatase and osteocalcin levels; high bone turnover confirmed by kinetic studies carried out with radiocalcium or 99mTc-MDP. An etiological classification of the osteomalacias includes: 1) nutritional osteomalacia: a) inadequate exposure to sunlight and/or insufficient vitamin D intake; b) defective intestinal absorption of vitamin D because of malabsorption syndromes (e.g. jejuno-ileal bypass for obesity).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The osteomalacias. 166 41

We used quantitative assays to measure the activity of the bone, liver, and intestinal forms of alkaline phosphatase in plasma in 75 patients with endstage chronic renal failure undergoing hemodialysis. The results were correlated with radiological and other biochemical indices of bone disease and with biochemical indices of liver disease. The total activity of alkaline phosphatase in plasma increased in 28 patients. In 10 of these patients, nine of whom had increased activity of gamma-glutamyltransferase in plasma, the increase in total activity of alkaline phosphatase was from the liver isoenzyme alone (nine patients) or from the liver and bone isoenzymes together (one patient). Intestinal alkaline phosphatase in plasma, although greater than 23 U/L in eight patients, was solely responsible for the increase in total alkaline phosphatase in one patient (who had normal gamma-glutamyltransferase). Bone alkaline phosphatase in plasma was increased in 25 patients, seven of whom had normal total alkaline phosphatase, and was closely correlated (r = 0.78) with osteocalcin concentration in plasma, which was increased in a much greater proportion of patients (99%). Both total and bone alkaline phosphatase were correlated with parathyrin in plasma (r = 0.46 and 0.50, respectively) and with osteocalcin (r = 0.60 and 0.78, respectively). Osteocalcin and bone alkaline phosphatase, but not parathyrin, decreased with age, implying that the skeletal response to parathyrin may be age dependent. In patients with increased total alkaline phosphatase undergoing hemodialysis, the concurrent measurement of gamma-glutamyltransferase may help identify whether the enzyme increase originates from the liver or bone, but this approach wrongly identified the source of the increase in three of 28 patients. Therefore, we recommend a separate measurement of the bone isoenzyme of alkaline phosphatase.
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PMID:Multiple forms of alkaline phosphatase in plasma of hemodialysis patients. 204 42

A newly established human osteosarcoma cell line, HS-Os-1, from an osteoblastic tumor arising in the left humerus of an 11-year-old girl was morphologically characterized in vitro and in vivo. HS-Os-1 cells in a monolayer have been maintained for more than 2 years since the initial cultivation, and were round or polygonal in shape with marked pleomorphism. Their cytoplasm was strongly positive for specific markers of osteoblasts, such as alkaline phosphatase and osteocalcin. Tumors induced in nude mice by HS-Os-1 cell inoculation at passage 12 or 23 revealed typical histological features of osteoblastic osteosarcoma, similar to those observed in the original tumor, producing prominent osteoid matrix with calcification. Ultrastructurally, HS-Os-1 cells in vitro and tumor cells in vivo showed similar well-developed, markedly dilated rough endoplasmic reticulum, polysomes and microfilaments in their cytoplasm. Additionally, many collagen fibers associated with deposition of electron-dense material were detected in the stroma featuring osteoid matrix. Thus, the HS-Os-1 cell line was shown to exhibit its osteoblastic nature in vitro and in vivo, and therefore might become an extremely useful tool for various pathomorphological investigations on human osteosarcomas.
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PMID:Morphological characterization of a newly established human osteosarcoma cell line, HS-Os-1, revealing its distinct osteoblastic nature. 167 69

Osteocalcin (OC) is a bone-specific protein whose blood concentration is a specific and sensitive marker of bone turnover. In adults undergoing continuous ambulatory peritoneal dialysis (CAPD), mean serum osteocalcin levels (S-OC) are lower than in similar patients on hemodialysis. We therefore measured the serum (S) and dialysate (D) levels of OC, estimated the peritoneal clearance (Cp) and mass transfer (MT) of OC and evaluated the relationship between S-OC levels and other serum biochemical parameters of bone metabolisms. Fourteen adult patients on CAPD were studied with a mean age of 46.3 +/- 13 years and a mean dialytic age on CAPD of 17.4 +/- 9.6 months. OC concentrations in (S) and (D) were 60.8 +/- 55.5 micrograms/l (normal range: 4.3-12.4 micrograms/l) and 6.9 +/- 6.2 micrograms/l, respectively. The Cp of OC was 1.08 +/- 0.3 ml/min and the MT of OC over 4-h dialysis exchange periods was 14.5 +/- 12.3 micrograms when using a dialysis solution containing 2.27% glucose. S-OC was significantly correlated with serum levels of alkaline phosphatase (r = 0.80), intact PTH (r = 0.82) and the MT of OC (r = 0.94). No significant correlations were found with serum levels of total calcium, phosphate, creatinine, total protein and dialytic age. These results suggest that the OC level in serum is influenced by both bone turnover and peritoneal clearance. Therefore, altered serum levels of OC should be interpreted always together with the peritoneal mass transfer of OC. Taking this into account, OC and intact PTH may be of value as markers of increased bone turnover secondary to renal osteodystrophy in CAPD.
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PMID:Clearance of osteocalcin in adults with end-stage renal disease undergoing CAPD. 168 Apr 31

In order to investigate the mechanism by which the inorganic content of the bone is reduced in chronic alcoholism, the authors assayed osteocalcin in 60 chronic alcoholics. The level was significantly lower than in control subjects. There was no significant difference between levels in cirrhotics and in non-cirrhotic alcoholics. There was a negative correlation between osteocalcin and gamma GT levels. There was no correlation between osteocalcin and blood calcium, blood phosphorus, ALAT, ASAT, alkaline phosphatase, 5'-nucleotidase, albumin or bilirubin levels, or with the prothrombin time. These results suggest a direct impact of alcohol on the osteoblast.
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PMID:[Osteocalcin in chronic alcoholism]. 168 99

To evaluate the age-related changes in the bone remodeling rate, the vitamin D status, and parathyroid function of healthy Chinese women, we selected two serum markers of bone turnover, osteocalcin and alkaline phosphatase (ALP). These markers as well as vitamin D metabolites and parathyrin (parathyroid hormone, PTH) were tested in healthy Chinese female volunteers aged 18 to 80 years residing in the Taipei urban area. The results showed no significant change with aging in the 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D) and immunoreactive c-terminal PTH (i-cPTH) serum levels. However, there was a trend towards lower 25(OH)D levels at the two extremes of age. The serum levels of 1,25(OH)2D and i-cPTH were comparable with reports of other countries. The serum 25(OH)D levels of our subjects were in general lower than those reported in U.S. white women, but similar to those of European women. The serum osteocalcin levels showed a triphasic change: high in early adulthood, decreasing during the 4th decade of life and then increasing continuously until age 70. After age 70, a decreasing trend was again seen. The serum ALP levels showed a continuous increase from the 3rd to the 8th decade of life. All of the subjects had their bone mineral density (BMD) measured. Linear or polynominal regression analysis as well as multiple regression analysis failed to show a significant correlation between the serum parameters and the BMD measurements at various sites.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Age-related changes in vitamin D metabolites, osteocalcin, alkaline phosphatase and parathyrin in normal Chinese women in Taipei. 168 46

The relationship of cell proliferation to the temporal expression of genes characterizing a developmental sequence associated with bone cell differentiation was examined in primary diploid cultures of fetal calvarial derived osteoblasts by the combined use of autoradiography, histochemistry, biochemistry, and mRNA assays of osteoblast cell growth and phenotypic genes. Modifications in gene expression define a developmental sequence that has 1) three principle periods--proliferation, extracellular matrix maturation, and mineralization--and 2) two restriction points to which the cells can progress but cannot pass without further signals--the first when proliferation is down-regulated and gene expression associated with extracellular matrix maturation is induced, and the second when mineralization occurs. Initially, actively proliferating cells, expressing cell cycle- and cell growth-regulated genes, produce a fibronectin/type I collagen extracellular matrix. A reciprocal and functionally coupled relationship between the decline in proliferative activity and the subsequent induction of genes associated with matrix maturation and mineralization is supported by 1) a temporal sequence of events in which there is an enhanced expression of alkaline phosphatase immediately following the proliferative period, and later, an increased expression of osteocalcin and osteopontin at the onset of mineralization; 2) increased expression of a specific subset of osteoblast phenotype markers, alkaline phosphatase and osteopontin, when proliferation is inhibited by hydroxyurea; and 3) enhanced levels of expression of the osteoblast markers as a function of ascorbic acid-induced collagen deposition, suggesting that the extracellular matrix contributes to both the shutdown of proliferation and the development of the osteoblast phenotype.
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PMID:Progressive development of the rat osteoblast phenotype in vitro: reciprocal relationships in expression of genes associated with osteoblast proliferation and differentiation during formation of the bone extracellular matrix. 169 81

Interleukin 6 (IL-6) exerts well-established effects on cells of the immune system as well as on various other cell types. It has been implicated in the control of connective tissue cells in such conditions as rheumatoid arthritis and osteoporosis. We have investigated the effects of recombinant human interleukin-6 (rhIL-6) on human osteoblastlike cells derived from explants of trabecular bone. ROS 17/2.8 cells were used as an additional osteoblastlike cell model system. We were unable to identify any effects of rhIL-6 (5-5000 pg/ml) on the proliferation, alkaline phosphatase activity. osteocalcin production, or release of cytokines or prostaglandins by either osteoblastlike cell model system. Since we have shown previously that these cells release IL-6 in culture, we used a sheep anti-human IL-6 antibody to investigate the possibility that (1) action of added exogenous IL-6 could be masking endogenous production, and (2) endogenous IL-6 may regulate the effects of osteotropic agents on the osteoblastlike cells. Presence of the antibody exerted no detectable effects on 1,25-(OH)2D3-stimulated alkaline phosphatase or on proliferation or TNF production enhanced by IL-1. Thus IL-6 does not appear to be involved in the regulation of osteoblast activity.
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PMID:Human osteoblastlike cells do not respond to interleukin-6. 170 32

Bovine capillary and microvessel pericytes were grown in monolayer in standard tissue culture medium supplemented with 10% newborn calf serum at various oxygen tensions for up to ten weeks. The pericytes synthesized alkaline phosphatase and formed colonies that mineralized. Energy dispersive X-ray spectrometry revealed the presence of calcium and phosphate, showed positive staining for collagen and glycosaminoglycan, and, most importantly, demonstrated the synthesis of osteocalcin. Cell proliferation, hydroxyproline production, and alkaline phosphatase synthesis were greatest in 3% oxygen, whereas osteocalcin production was least in 3% oxygen. These findings demonstrate that the capillary or microvessel pericyte exhibits phenotypic expressions in vitro that are similar to that of in vitro bone cells, and these expressions may be somewhat oxygen dependent. It is suggested from these findings that the capillary or microvessel pericyte may be an osteoblast precursor cell.
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PMID:The pericyte as a possible osteoblast progenitor cell. 173 27

To investigate whether bone resorption exhibits a diurnal variation in healthy premenopausal women, we measured urinary excretion of pyridinoline and deoxypyridinoline cross-links (U-Pyr/Cr and U-D-Pyr/Cr) every 3 h over a 24-h period in 12 healthy premenopausal women (mean +/- 1 SD age, 32 +/- 5 yr). To study diurnal variation, U-Pyr/Cr and U-D-Pyr/Cr are the best available markers of bone resorption for a diurnal variation study, as they are not influenced by diet. Plasma osteocalcin and serum alkaline phosphatase (markers of bone formation) were also measured. A marked diurnal rhythm was observed in U-Pyr/Cr and U-D-Pyr/Cr, with the peak between 0500-0800 h and the nadir between 1400-2300 h. The fluctuation was 2-fold over the 24-h period, with a mean fall of 25-35% between 0800-1100 h. This study demonstrates a marked diurnal variation in the new biochemical markers of bone resorption, U-Pyr/Cr and U-D-Pyr/Cr, in premenopausal women. Furthermore, this study emphasizes the importance of regulating the time of the urine sample taken for measuring urinary pyridinium cross-links for clinical investigations as well as in clinical practice.
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PMID:Marked diurnal variation in urinary excretion of pyridinium cross-links in premenopausal women. 174 Apr 79


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