Clinical implications of estimation of intact parathyroid hormone (PTH) versus total immunoreactive PTH in normal subjects and hyperparathyroid patients.

We describe a clinical study comparing the value of measurements of intact human PTH [hPTH(1-84)] and total PTH immunoreactivity [hPTH-(1-84) plus fragments]. A two-step immunochemical method was used to separate plasma hPTH-(1-84) from all circulating PTH fragments. The first step involved extraction and concentration of plasma PTH using solid phase antiamino-terminal PTH antibodies.

Absence of effect of 24,25-dihydroxyvitamin D3 in primary hyperparathyroidism.

Nineteen patients with primary hyperparathyroidism were treated with 25 micrograms 24,25-dihydroxyvitamin D3 or placebo daily for 3 months according to double-blind cross-over protocol. Serum immunoreactive PTH, total and ionized calcium, urinary calcium excretion, tubular reabsorption of phosphate/glomerular filtrate, and urinary hydroxyproline excretion did not change significantly. Serum 24,25-dihydroxyvitamin D3 levels increased significantly from 1.

Bone metabolism in rheumatoid arthritis compared with postmenopausal osteoporosis.

Calcium and bone metabolism in 29 rheumatoid arthritis (RA) patients were compared with those in 27 postmenopausal osteoporotic patients. Signs of vitamin D deficiency were found in 20 RA patients, including 12 who took recommended amounts of vitamin D in their diets and were exposed to sufficient sunlight, and in none of the osteoporotic patients. There were no signs of malabsorption.

[Vitamin D deficiency and hip fracture].

Vitamin D deficiency is common in the elderly, especially in patients with hip fracture. Elderly people infrequently stay outside in the sunshine, and nutrition is deficient in vitamin D. In addition, the hydroxylation of vitamin D into active metabolites decreases with age.

Vitamin D status in urinary calcium stone formation.

Serum vitamin D metabolites were measured in 160 normocalcemic urinary calcium stone formers and in 217 control subjects. No difference in concentrations of 25-hydroxy-vitamin D (25[OH]D), 24,25-dihydroxyvitamin D (24,25[OH]2D), and 1,25-dihydroxyvitamin D (1,25[OH]2D) was found between stone formers and control subjects. Values for 25(OH)D and 24,25(OH)2D were higher in hypercalciuric stone formers than in normocalciuric stone formers independent of seasonal fluctuation.

Bone mineral content of transilial biopsies in patients with hip fracture.

In a survey of 125 patients with hip fracture vitamin D deficiency was frequently observed, but overt osteomalacia was not found in the bone biopsies (Lips et al., 1982). In order to detect a possible hypomineralization in these vitamin D-deficient patients, we measured the bone mineral content in 64 transilial biopsies, embedded in methylmethacrylate for histomorphometric evaluation.

The effect of trauma on serum concentrations of vitamin D metabolites in patients with hip fracture.

In a previous study we observed lower serum concentrations of 25(OH)D, 24,25(OH)2D, and 1,25(OH)2D in patients with hip fracture than in aged control subjects. In order to evaluate the effect of trauma on vitamin D metabolite levels, we measured serum concentrations of vitamin D binding protein (DBP) in 118 patients with hip fracture and 71 aged control subjects. Serum DBP was lower in the patients than in the controls (mean +/- SD 315 +/- 60 vs 371 +/- 44 mg/l, P less than 0.

Radiologic morphometry in patients with femoral neck fractures and elderly control subjects. Comparison with histomorphometric parameters.

Radiologic morphometry was performed in 125 patients with femoral neck fractures and 74 elderly control subjects to evaluate simple parameters for screening of the population at risk. Reproducibility of metacarpal cortical thickness was high when measured in six metacarpals. Values of this parameter were similar in patients and control subjects.

An international comparison of vitamin D metabolite measurements.

An international 19-laboratory survey was organized to compare assays for 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D in plasma. Each participant received two ethanolic standard solutions of each metabolite and eight plasma samples. Each laboratory used its usual procedures.

Measurement of vitamin D metabolites in anephric subjects.

Circulating concentrations of 1,25-dihydroxyvitamin D, 24,25-dihydroxyvitamin D and 25-hydroxyvitamin D were measured in 21 anephric subjects. 13 subjects had no therapy with vitamin D, dihydrotachysterol or 1 alpha-hydroxyvitamin D3. In 7 subjects of this group 1,25-dihydroxyvitamin D was undetectable (less than 5 pmol/l).

Hyperparathyroidism following irradiation of benign diseases of the head and neck.

In a series of 73 consecutive patients with hyperparathyroidism (HPT) eight patients gave a history of irradiation of head and neck because of benign diseases. The average interval between irradiation and definite diagnosis was 34 years. Intermittent hypercalcaemia was found in three patients.

Seasonal variation in serum concentrations of parathyroid hormone in elderly people.

In 124 patients with femoral neck fracture and 74 aged control subjects a seasonal variation was observed in the serum concentrations of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and PTH. The serum PTH concentrations were maximal in winter, when the vitamin D metabolites were lowest, suggesting a secondary phenomenon.

Simultaneous determination of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D in plasma or serum.

We describe a simultaneous assay for the principal vitamin D metabolites: 25-hydroxyvitamin D, 24-25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D. Special attention has been paid to simplification of the extensive extraction and purification procedures used in previously described simultaneous assays. All three metabolites were isolated with a single extraction step, followed by only one gradient liquid-chromatographic procedure.

Mean wall thickness of trabecular bone packets in the human iliac crest: changes with age.

The mean wall thickness (MWT) of packets of trabecular bone was measured in undecalcified iliac crest bone samples of 36 normal subjects (14 female and 22 male) under polarized light. The mean wall thickness was 49.7 +/- 8.