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)

Although the measurement of total alkaline phosphatase activity in serum is a valid index to assess the activity of Paget's disease of bone and to monitor treatment efficacy, this marker may lack sensitivity in some cases. Among the various markers of bone formation and resorption that have been developed, serum bone specific alkaline phosphatase and procollagen I N-terminal peptide (PINP) for formation, urinary N-telopeptide (NTX) and alpha-C-telopeptide (CTX) for bone resorption have emerged as the most sensitive ones, and may be useful in the management of pagetic patients. We have recently shown that the beta-isomerization of type I collagen CTX is impaired in pagetic bone matrix characterized by the existence of woven bone, as compared to normal lamellar bone matrix. This abnormality results in a preferential urinary excretion of nonisomerized (alpha-CTX) over beta-isomerized (beta-CTX) that can be measured with specific immunoassays. Patients with active Paget's disease of bone are characterized by an abnormally high alpha/beta-CTX ratio which goes down to the normal range after bisphosphonate therapy, probably reflecting the lamellar structure of newly formed bone matrix in pagetic skeletal sites after treatment.
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PMID:Biochemical markers of bone turnover in Paget's disease of bone. 1051 Feb 16

Quantitative ultrasound (QUS) of bone and new markers of bone remodeling have been poorly investigated in mild primary hyperparathyroidism (PHPT). In this study 26 patients (20 females and 6 males) were evaluated. BUA and SOS were measured by QUS at the heel. Markers of bone remodeling assessed were bone alkaline phosphatase (BAP), osteocalcin (OC), procollagen type I N- and C-terminal propeptides (PINP et PICP), and procollagen type I C-terminal telopeptide in blood and urine (ICTP and CTX). Bone mineral density (BMD) was measured at the lumbar spine (LS), femoral neck (FN), and Ward's triangle (WT). The control group comprised 35 sex- and age-matched subjects. The statistically significant variables between the two groups were (P < 0.05) BUA, BMD(LS), BMD(FN), BMD(WT), BAP, and OC. Corresponding z-scores were -0.55 +/- 0.75, -0.66 +/- 0.77, -0.66 +/- 0.71, -0.67 +/- 0.52, 1.87 +/- 3.87, and 1.93 +/- 3.53, respectively. Although PICP and PINP levels were higher in PHPT patients as compared with controls, the difference was not significant. Several markers of bone turnover were moderately correlated with both QUS (r = -0.39 to -0.55) and BMD (r = -0.48 to 0.63). In conclusion QUS seems to be a relevant tool in the assessment of bone status for patients with mild PHPT.
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PMID:Bone ultrasonometry and turnover markers in primary hyperparathyroidism. 1060 38

We studied 41 normal pregnant women and their neonates in order to compare bone metabolism between them. We examined more specific bone formation markers (intact osteocalcin, bone-specific alkaline phosphatase) and a recently developed and more sensitive bone resorption marker (C-telopeptide of type I collagen; CTX) than previously available in maternal and umbilical cord venous blood taken at delivery. The concentrations of all markers of bone turnover, including CTX, in cord serum were significantly higher than those in maternal serum. There was no significant correlation between maternal and cord serum levels for any marker. These results indicate that fetal bone turnover is markedly enhanced compared with maternal bone turnover and is independent of maternal bone metabolism in late pregnancy.
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PMID:Comparison of bone metabolic markers between maternal and cord blood. 1064 Aug 88

Fragments derived from degradation of type I collagen C-telopeptide (CTX) can be nonisomerized (alpha) or beta-isomerized (beta) depending on the age of bone; i.e., mainly the alpha form is derived from new bone and the beta form from old bone. We have studied 41 female patients with anorexia nervosa (AN), aged 18.5 +/- 2.2 years (range 16-24 years), and with an evolution time between 1.5 and 11 years, and 31 healthy control females (C), with a mean age of 19 +/- 2.3 years (range 16-24 years). The AN patients showed a significant decrease in bone mass, with a mean Z-score of bone mineral density (BMD) of -3.2 +/- 0.8 (range -0.9 to -5.4). The aim of our study was to determine the levels of urinary alpha- and beta-CTX markers of bone resorption, the alpha/beta ratio (alpha/beta), and the level of bone alkaline phosphatase (bAP), a biochemical marker of bone formation, in order to relate them to the degree of osteopenia and the status of bone remodeling. Statistical analysis was by the Mann-Whitney test. The degree of osteopenia correlated with bAP levels (p = 0.0027) but not with the other parameters. Patients with AN were divided into three groups according to their levels of bAP: high (H), normal (N) or low (L). We found that BMD was significantly lower, and alpha- and beta-CTX were significantly higher, in groups H and N than in group L. Bone AP correlated significantly with alpha-CTX (p = 0.0042) and alpha/beta (0.0095) in the controls, but not with beta-CTX, while in AN patients bAP correlated with beta-CTX (p = 0.0000) and with alpha-CTX (p = 0.022) but not with the alpha/beta ratio. The ratio CTX/bAP (resorption/formation) was similar in AN patients and controls. It is concluded that: (1) patients with AN have a high degree of osteopenia which correlated with bAP levels; (2) urinary CTX fragments found in AN patients seem to come mainly from old bone (beta-CTX), while CTX found in healthy adolescent control females come from new bone (alpha-CTX). For this reason, alpha-CTX is more suitable than beta-CTX for measuring bone resorption in controls and beta-CTX is more suitable in patients with AN; (3) the resorption/formation ratio (CTX/bAP) was similar in AN patients and controls. From points (2) and (3) it is possible to suggest that, although bAP reflects bone formation in control females, this marker does not reflect effective bone mineralization in AN patients, a similar feature to that of patients with osteomalacia.
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PMID:Urinary alpha and beta C-telopeptides of collagen I: clinical implications in bone remodeling in patients with anorexia nervosa. 1066 49

Although increased bone formation is a prominent feature of patients with osteosclerotic metastases from prostate cancer, there is also some evidence for increased bone resorption. The aim of this study was to compare the clinical utility of new bone resorption markers to that of bone formation in patients with bone metastases from prostate cancer before and after bisphosphonate treatment. Thirty-nine patients with prostate cancer and bone metastasis, nine patients with prostate cancer without bone metastases, nine patients with benign prostatic hyperplasia and 355 healthy age-matched men were included. Urinary non-isomerized (alpha CTX) and beta isomerized (beta CTX) type I collagen C-telopeptides (CTX) and a new assay for serum CTX were used to assess bone resorption. Bone formation was determined by serum osteocalcin, serum total (T-ALP) and bone (BAP) alkaline phosphatase and serum type I collagen C-terminal propeptide (PICP). Fourteen patients with bone metastases were also evaluated 15 days after a single injection of the bisphosphonate pamidronate (120 mg). Levels of all bone formation and bone resorption markers were significantly (P < 0.006-0.0001) higher in patients with prostate cancer and bone metastasis than in patients with benign prostatic hyperplasia, patients with prostate cancer without bone metastases and healthy controls. In patients with bone metastases the median was increased by 67% for serum osteocalcin, 128% for T-ALP, 138% for BAP, 79% for PICP, 220% for urinary alpha CTX, 149% for urinary beta CTX and 214% for serum CTX. After bisphosphonate treatment all three resorption markers significantly decreased by an average of 65% (P = 0.001), 71% (P = 0.0010) and 61% (P = 0.0015) for urinary alpha CTX, urinary beta CTX and serum CTX, respectively, whereas no significant change was observed for any bone formation markers. Patients with prostate cancer and bone metastases exhibit a marked increase in bone resorption, which decreases within a few days of treatment with pamidronate. These findings suggest that these new resorption markers may be useful for the management of these patients.
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PMID:Markers of bone turnover for the management of patients with bone metastases from prostate cancer. 1073 59

Hormone replacement therapy (HRT) induces a rapid decrease in biochemical markers of bone turnover that correlate with a subsequent increase in bone mineral density (BMD). To determine the utility of bone markers in the management of postmenopausal women receiving HRT, we analyzed the relationship between changes in four markers (serum osteocalcin and bone alkaline phosphatase [BAP], serum and urinary C-telopeptide of type I collagen [CTX]) and changes in spine BMD in 569 women treated for 2 years with different doses of a matrix transdermal 17beta-estradiol patch in two placebo-controlled trials. Using a logistic regression model, we found that both the percent change from baseline and the actual value of resorption markers at 3 and 6 months of treatment were predictive of BMD response at 2 years. Comparable results were obtained with formation markers at 6 months only. We determined the sensitivity, probably of positive BMD response, and corresponding cutoff value of markers at 3 and 6 months with a specificity set at a level of 0.90, so that <10% of women classified with markers as responders, i.e., as having a subsequent increase in BMD at 2 years >/=2.26%, would be false positive. All markers provided a high probability of positive BMD response ranging from 0.82 to 0.91, with a sensitivity higher for resorption than for formation markers, and sometimes improved in a model combining the percent change and the actual value of marker under HRT. For example, a decrease in serum CTX >/= 33% at 3 months of HRT provided a 68% sensitivity and 87% probability of positive BMD response at 2 years for a 90% specificity. At 6 months, a decrease in urinary CTX >/= 53% provided a 68% sensitivity and 91% probability of a positive BMD response for a 90% specificity. Half of false-negative cases at 3 months will be correctly identified by a subsequent urinary CTX measurement at 6 months. We conclude that the short-term change in bone markers reflects long-term changes of BMD in postmenopausal women treated with HRT. Our data suggest that bone turnover markers can be used to monitor the BMD response to HRT at the individual level. Whether such monitoring could improve long-term compliance to HRT should be tested prospectively.
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PMID:Monitoring individual response to hormone replacement therapy with bone markers. 1083 24

Biochemical measurements of bone turnover are helpful in the study of the pathophysiology of skeletal metabolism and growth. However, interpretation of their results is difficult because they depend on age, pubertal stage, growth velocity, mineral accrual, hormonal regulation, nutritional status, circadian variation, day-to-day variation, method of expression of results of urinary markers, specificity for bone tissue, sensitivity and specificity of assays. Three markers of bone formation have been described including their bone specificity and age-related changes: osteocalcin, alkaline phosphatase and its skeletal isoenzyme, procollagen I extension peptides. Bone resorption markers (hydroxyproline; deoxypyridinoline; pyridinoline; peptides containing these crosslinks such as N-telopeptide to helix in urine (NTX), C-telopeptide-1 to helix in serum (ICTP) and C-telopeptide-2 in urine and serum (CTX); tartrate-resistant acid phosphatase; hydroxylysine and its glycosides) are described with special attention to methodologic issues, mainly ways of expression of their results. Changes of bone turnover during growth are described during four periods: infancy, prepubertal period, puberty and the postpubertal period. Pubertal changes of bone markers are described with special attention to gender differences and hormonal mechanisms of the growth spurt which determine differences related to the pubertal stage. Disturbances of bone turnover in four conditions are described to illustrate the impact of such diseases on growth and formation of peak bone mass: prematurity, malnutrition, growth hormone deficiency and corticosteroid-treated bronchial asthma. Available data suggest biochemical markers of bone remodeling may be useful in the clinical investigation of bone turnover in children in health and disease. However, their use in everyday clinical practice is not advised at present.
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PMID:Biochemical measurements of bone turnover in children and adolescents. 1092 17

The mechanisms leading to increased bone loss and skeletal fragility in women with postmenopausal osteoporosis are still poorly understood. Increased bone resorption, low serum estradiol and high serum sex-hormone-binding globulin (SHBG) recently have been reported as predictors of vertebral and hip fractures in elderly women. In a cohort of healthy untreated younger postmenopausal women aged 50-89 years (mean, 64 years), we compared baseline levels of bone markers and endogenous hormones in 55 women who subsequently had a fracture (20 vertebral and 35 peripheral fractures) with levels in the 380 women who did not fracture during a mean 5 years of follow-up. Women with levels in the highest quartile of four bone resorption markers including urinary-free deoxypyridinoline (D-Pyr), urinary type I collagen N-telopeptides (NTX), and urinary and serum type I collagen C-telopeptides (CTX) had about a 2-fold increased risk of fractures compared with women with levels in the three lowest quartiles with relative risk (RR) and 95% CI of 1.8 (1.0-3.4) for free D-Pyr, 1.7 (0.9-3.2) for urinary NTX, 2.3 (1.3-4.1) for urinary CTX, and 2.1 (1.2-3.8) for serum CTX. Serum levels of bone alkaline phosphatase (BAP) in the highest quartile were associated with an RR of fracture of 2.4 (1.3-4.2). Women with serum levels of estradiol and dehydroepiandrosterone (DHEA) sulfate in the lowest quartile had an RR of fracture of 2.2 (1.2-4.0) and 2.1 (1.2-3.8), respectively. Increased levels of SHBG and intact parathyroid hormone (PTH) were moderately associated with an increased risk of fracture. Similar results were obtained when the analysis was restricted to symptomatic vertebral and nonvertebral fractures. Adjustment of biochemical markers by hormone levels did not significantly alter the results. Women with both high bone resorption markers and low estradiol (or low DHEA sulfate) had a higher risk of fracture with RRs of 3.0-3.3 (p < 0.001). After adjustment for bone mineral density (BMD) of the hip, spine, radius, or total body, bone markers and hormones were still predictive of fracture risk with similar RRs. We conclude that high levels of some biochemical markers of bone turnover, low serum estradiol, low DHEA sulfate, high SHBG, and high PTH are associated with increased risk of osteoporotic fracture in postmenopausal women, independently of each other and of BMD. The mechanism by which some postmenopausal women have an increased rate of bone turnover leading to an increased risk of fracture remains to be elucidated.
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PMID:Biochemical markers of bone turnover, endogenous hormones and the risk of fractures in postmenopausal women: the OFELY study. 1093 51

Bone loss before and around the time of menopause is not well characterized by longitudinal studies. We measured bone mineral density at various skeletal sites--total body, femoral neck, trochanter, anteroposterior (AP) and lateral spine, and forearm--with dual-energy X-ray absorptiometry in a large prospective cohort of 272 untreated pre- and perimenopausal women aged 31-59 years, at 1 year intervals for 3 years. Sex steroids and the following markers of bone remodeling were measured: serum osteocalcin (OC), procollagen I carboxyterminal extension peptide, bone alkaline phosphatase (BAP) and urinary crosslinks (CTX and NTX). Seventy-six women were classified as perimenopausal and 196 as premenopausal. Over the 3 years, premenopausal women had no significant bone loss at any site and a small but significant increase in bone mineral density at the trochanter, total hip, AP spine and radius. Perimenopausal women significantly lost bone from cancellous and cortical sites, i.e., the femoral neck, trochanter and lumbar spine. In perimenopausal women with increased follicle stimulating hormone, the rate of bone loss at the femoral neck correlated negatively with OC and BAP. In perimenopausal women, serum estradiol levels decreased during the 3 years of follow-up and bone loss from the trochanter and the AP spine was correlated with serum estradiol after 3 years. In conclusion, among premenopausal women there is no bone loss. In contrast, there is a rapid and diffuse bone loss in perimenopausal women, related to decreased estrogen secretion. Bone markers may be useful to identify these women losing bone.
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PMID:Longitudinal study of bone loss in pre- and perimenopausal women: evidence for bone loss in perimenopausal women. 1098 64

Evidence for the role of estrogen in male bone metabolism has been confirmed by studies on a man with a genetic defect in the estrogen receptor as well as men with aromatase defects. All exhibited tall stature, delayed epiphysial closure, decreased bone density and increased bone turnover. Estrogen is likely to affect bone turnover in men throughout life; therefore, we hypothesized that older men would show decreased bone resorption in response to estrogen therapy. To test our hypothesis, fourteen community-dwelling men with osteopenia of the femoral neck were treated for 9 weeks with micronized estradiol, 1 mg/d, a dose which is effective in postmenopausal women. Each subject served as his own control. Markers of bone resorption, N-terminal collagen crosslinks (NTX) and C-terminal collagen crosslinks (CTX) and markers of bone formation, osteocalcin (OC) and bone specific alkaline phosphatase (BSAP) were measured every 3 weeks during a 9-week treatment period and 9 weeks post-treatment. Sex hormones, gonadotrophins and calciotropic hormones were measured at baseline, 9 weeks on treatment and 9 weeks post- treatment. After 9 weeks of treatment, estradiol and estrone levels increased significantly by greater than 6-fold and 15-fold, respectively. SHBG levels increased significantly by 17%. Testosterone and free testosterone levels decreased significantly by 27% and 34%, respectively. Markers of bone resorption showed wide variation at baseline and while on treatment. There was no correlation between changes in bone markers and changes in estrogen levels. During treatment, 11 patients showed a decrease of NTX or CTX, but three showed an increase. These three and one other subject had high initial levels of FSH and LH, suggesting some degree of primary gonadal failure, which decreased during estrogen therapy. Thus, the change in NTX (and CTX) after 9 weeks of E2 treatment was correlated with initial FSH (r= -.66, p= .01) and LH (r= -.73, p= .003) values. In addition, the largest decrease in free testosterone at 9 weeks was correlated with the higher values for NTX, CTX and BAP (r=-0.66, -0.68, -0.70 respectively; p< or =.01 for each of the markers). Treatment was generally well tolerated. Side effects of treatment were minimal, and included breast tenderness and decreased libido which reversed after treatment. We conclude that it is feasible to give low dose estrogen to healthy older men, but that the effects on bone turnover are not consistent. Changes in central feedback and in endogenous sex hormone production may alter the response of bone turnover to exogenous estrogen in this population.
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PMID:The effect of short-term treatment with micronized estradiol on bone turnover and gonadotrophins in older men. 1101 3


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