Scintillation proximity assay for calcitriol in serum without high pressure liquid chromatography

Wildermuth, Susanne; Dittrich, Karin; Schmidt‐Gayk, H.; Zahn, Ingrid; O’Riordan, J. L. H.

doi:10.1016/0009-8981(93)90006-p

Cited by 14 publications

(8 citation statements)

References 54 publications

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“…Serum intact PTH was determined by immunoluminometric assay (reference range, 11‐54 pg/ml; Chiron Diagnostics Magic Lite, Cergy Pontoise, France). 1,25‐dihydroxyvitamin D [1,25(OH) 2 D] was measured using an in‐house radioimmunoassay (reference range, 32‐80 ng/liter) as previously described (35) …”

Section: Methodsmentioning

confidence: 99%

“…[1,25(OH) 2 D] was measured using an in-house radioimmunoassay (reference range, 32-80 ng/liter) as previously described. (35) A solid-phase, two site immunoradiometric assay (Tandem-R Ostase; Hybritech, San Diego, CA, USA) was used to determine serum bone-specific alkaline phosphatase (BSAP). (36) Intra-and interassay CVs ranged between 3.7% to 6.7% and 7.0% and 8.1%, respectively.…”

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confidence: 99%

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Supplementation With Oral Vitamin D3 and Calcium During Winter Prevents Seasonal Bone Loss: A Randomized Controlled Open-Label Prospective Trial

Meier

Woitge

Witte

et al. 2004

Journal of Bone and Mineral Research

178

103

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Bone metabolism follows a seasonal pattern with high bone turnover and bone loss during the winter. In a randomized, open-label 2-year sequential follow-up study of 55 healthy adults, we found that supplementation with oral vitamin D 3 and calcium during winter abolished seasonal changes in calciotropic hormones and markers of bone turnover and led to an increase in BMD. Supplementation with oral vitamin D 3 and calcium during the winter months seems to counteract the effects of seasonal changes in vitamin D and thus may be beneficial as a primary prevention strategy for age-related bone loss.Introduction: Bone metabolism follows a seasonal pattern characterized by high bone turnover and bone loss during winter. We investigated whether wintertime supplementation with oral vitamin D 3 and calcium had beneficial effects on the circannual changes in bone turnover and bone mass. Materials and Methods:This prospective study comprised an initial observation period of 12 months ("year 1"), followed by an intervention during parts of year 2. Fifty-five healthy subjects living in southwestern Germany (latitude, 49.5°N) were randomized into two groups: 30 subjects were assigned to the treatment group and received oral cholecalciferol (500 IU/day) and calcium (500 mg/day) during the winter months of year 2 (October-April), while 25 subjects assigned to the control group obtained no supplements. Primary endpoints were changes in calciotropic hormones [serum 25(OH)D, 1,25(OH) 2 D, and parathyroid hormone], markers of bone formation (serum bone-specific alkaline phosphatase) and of bone resorption (urinary pyridinoline and deoxypyridinoline), and changes in lumbar spine and femoral neck BMD. Results: Forty-three subjects completed the study. During year 1, calciotropic hormones, markers of bone turnover, and BMD varied by season in both groups. During the winter months of year 1, bone turnover was significantly accelerated, and lumbar spine and femoral BMD declined by 0.3-0.9%. In year 2, seasonal changes in calciotropic hormones and markers of bone turnover were either reversed or abolished in the intervention group while unchanged in the control cohort. In the subjects receiving oral vitamin D 3 and calcium, lumbar and femoral BMD increased significantly (lumbar spine: ϩ0.8%, p ϭ 0.04 versus year 1; femoral neck: ϩ0.1%, p ϭ 0.05 versus year 1), whereas controls continued to lose bone (intervention group versus control group: lumbar spine, p ϭ 0.03; femoral neck, p ϭ 0.05). Conclusions: Supplementation with oral vitamin D 3 and calcium during winter prevents seasonal changes in bone turnover and bone loss in healthy adults. It seems conceivable that annually recurring cycles of low vitamin D and mild secondary hyperparathyroidism during the winter months contributes, at least in part and over many years, to age-related bone loss. Supplementation with low-dose oral vitamin D 3 and calcium during winter may be an efficient and inexpensive strategy for the primary prevention of bone loss in northern latitudes.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Supplementation With Oral Vitamin D3 and Calcium During Winter Prevents Seasonal Bone Loss: A Randomized Controlled Open-Label Prospective Trial

Meier

Woitge

Witte

et al. 2004

Journal of Bone and Mineral Research

178

103

View full text Add to dashboard Cite

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“…Therefore, the levels of 25‐hydroxyvitamin D 2 detected by the assay are insignificant and contribute less than 1% to the total circulating vitamin D pool. 1,25(OH) 2 D 3 was measured by in‐house radioimmunoassay as described previously (26) …”

Section: Methodsmentioning

confidence: 99%

Circannual Rhythms and Interactions of Vitamin D Metabolites, Parathyroid Hormone, and Biochemical Markers of Skeletal Homeostasis: A Prospective Study

Woitge

Knothe

Witte

et al. 2000

Journal of Bone and Mineral Research

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101

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“…The calcitriol concentration was measured by radioimmunoassay [10], the intraassay variability at concentrations of 30-70 ng/l being 8%. Total 25-hydroxycholecalciferol was measured by nonchromatographic assay as described recently [II].…”

Section: Methodsmentioning

confidence: 99%

Comparison of Intermittent and Continuous Oral Administration of Calcitriol in Dialysis Patients: A Randomized Prospective Trial

Herrmann¹,

Ritz²,

Schmidt‐Gayk³

et al. 1994

Nephron

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Intermittent bolus administration of calcitriol – i.e., 1,25-dihydroxycholecalcife-rol or 1,25-(OH)₂D₃ – is highly efficacious in dialysis patients. In experimental studies, intermittent administration of calcitriol is superior to continuous administration in suppressing preproparathyroid hormone (PTH) mRNA and circulating PTH concentrations. In a randomized, prospective, open multicenter trial 45 dialysis patients with elevated 1,84-iPTH ( > 20 pmol/l, normal 1-6 pmol/l) levels were randomly allocated to daily administration of 0.75 μg calcitriol (continuous) or twice weekly administration (intermittent); the two protocols provided an identical total weekly doses of 5.25 μg calcitriol. Patients were dialyzed with a dialysate Ca concentration of 1.75 mmol/l and had oral CaCO₃ or Ca acetate. 1,84-iPTH (immunoradiometric assay) and serum Ca and Pi levels were measured weekly. At the beginning of the study, the median 1,84-iPTH value was 37 pmol/l (range 20-115) in the intermittent versus 36 pmol/l (range 21-72) in the continuous calcitriol group. After 2 weeks, the median 1,84-iPTH level was 18.5 pmol/l (range 1.4-106) versus 18 pmol/l (range 1.2-48). After 12 weeks, 11 of 21 of the patients in the intermittent and 18 of 24 patients in the continuous group had reached the treatment goal, i.e., 1,84-iPTH < 10 pmol/l without hypercalcemia or hyperphosphatemia. There were seven episodes of hypercalcemia ( > 2.7 mmol/l) in the intermittent versus two in the continuous group; the mean peak Ca level was 2.8 mmol/l (range 2.76-3.0) versus 2.9 mmol/l (range 2.74-3.06). There were 21 versus 17 episodes, respectively, of hyperphosphatemia ( > 2.2 mmol/l).

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Scintillation proximity assay for calcitriol in serum without high pressure liquid chromatography

Cited by 14 publications

References 54 publications

Supplementation With Oral Vitamin D3 and Calcium During Winter Prevents Seasonal Bone Loss: A Randomized Controlled Open-Label Prospective Trial

Supplementation With Oral Vitamin D3 and Calcium During Winter Prevents Seasonal Bone Loss: A Randomized Controlled Open-Label Prospective Trial

Circannual Rhythms and Interactions of Vitamin D Metabolites, Parathyroid Hormone, and Biochemical Markers of Skeletal Homeostasis: A Prospective Study

Comparison of Intermittent and Continuous Oral Administration of Calcitriol in Dialysis Patients: A Randomized Prospective Trial

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