Concentration of 25-hydroxyvitamin D in serum of infants under the intermittent high-dose vitamin D3 prophylactic treatment.

The concentration of 25-hydroxyvitamin D was measured in serum of 90 healthy and 123 sick infants. The mean concentration of 25-OH-D in the group of healthy infants given intermittent prophylactic doses of vitamin D3 was 44.0 microgram/l and was nearly three times higher than the average concentration in healthy adults not given any vitamin D substitution. In the 123 clinically treated infants the average 25-OH-D concentration was 86.2 microgram/l, and 59.4% of infants had values over 40 microgram/l. In the subgroup of infants admitted to the hospital because of diarrhea, lower values were found than the average ones of clinically-treated infants. Two children with clinical rickets had very low 25-OH-D concentrations. The 25-OH-D half life in serum of infants varied from 19 to 27 days and single dose--300,000 IU (7.5 mg) of vitamin D3 was found to assure a sufficient 25-OH-D concentration in serum for as many as 190 days. It is concluded that high intermittent oral doses of vitamin D3 give an effective protection against rickets but at the cost of several times higher 25-OH-D concentration in serum and at the risk of hypervitaminosis D in some healthy infants.

25-hydroxyvitamin D in patients with essential hypertension.

Plasma 25-OH-D levels of normotensive and hypertensive subjects living in a highly industrial and in a nonindustrial area, were estimated. Significantly higher values were found in normotensive subjects than in hypertensive patients. Severity of arterial hypertension was not related to plasma 25-OH-D. Both groups of subjects (normotensive and hypertensive) living in the industrial area with high air pollution had lower 25-OH-D concentrations than those living in the nonindustrial region. Data presented in this paper suggest that antihypertensive treatment by pharmacologic agents exerts a depressive effect on plasma 25-OH-D level.

[Osteopathy and serum parathormone and 25-hydroxycholecalciferol levels in patients on long-term haemodialysis (author's transl)]. / Osteopathie, Parathormon- und 25-Hydroxycholekalziferol-Konzentrationen im Serum bei chronisch dialysierten Patienten.

Skeletal radiological changes were analyzed in 22 patients treated by chronic haemodialysis. Furthermore, the serum parathormone and 25-hydroxycholecalciferol concentrations were determined. X-ray evidence of renal osteopathy was found in 13 patients (59%). Extraskeletal calcification, subperiostal erosions and cystoids were the predominant lesions. Serum iPTH concentrations were increased in 21 out of 22 haemodialyzed patients. The serum 25-hydroxycholecalciferol concentration was normal. The results of this study seem to indicate that other factors apart from secondary hyperparathyroidism have a share in the development of renal osteopathy in patients on chronic haemodialysis.

Effects of 1alpha-hydroxyvitamin D3 on serum calcium and immunoreactive parathyroid hormone in patients with chronic renal insufficiency.

Six patients with chronic renal failure on regular dialysis treatment were given low doses (0.5--1.0 microgram/day) of 1alpha-hydroxyvitamin D3, monitoring the serum calcium, inorganic phosphate, immunoreactive parathyroid hormone concentration (IPTH) and alkaline phosphatase activity. The serum calcium rose in all patients after 7 days' treatment, in some subjects to hypercalcemic range; this effect persisted 6--14 days after withdrawal of 1alpha-hydroxyvitamin D3. The elevated serum IPTH rose in the first days of treatment, but later decreased to normal values. It is suggested that active vitamin D metabolites are necessary for normal response of parathyroid glands to variation in serum calcium. Low-dose 1alpha-hydroxyvitamin D3 treatment appears to be a promising method of correcting hypocalcemia and secondary hyperparathyroidism in chronic renal failure. Careful control of serum calcium is necessary, as hypercalcemia may occur even after minute doses of 1alpha-hydroxyvitamin D3.

[Pathophysiology and clinical aspects of parathyroid hormone]. / Zur Pathophysiologie und Klinik des Parathormons

In this paper the contemporary knowledge about structure, metabolism, secretion, level in blood plasma and diagnostic significance of the parathyroid hormone (PTH) is summarized. The difficulties connected with PTH estimations in human plasma are especially emphasized.

[The behavior of the parathyroid hormone secretion in hemodialyzed patients with chronic kidney failure]. / Das Verhalten der Parathormonsekretion bei hämodialysierten Patienten mit chronischer Niereninsuffizienz

In 15 patients with chronic renal insufficiency the influence of the haemodialysis on the level of the blood serum of immune-reactive parathormone (iPTH). In the therapy of dialysis a wash with high calcium content (= 8 mg/100 ml) was used. After a single haemodialysis a decrease of the iPTH-level was observed. After a dialysis therapy lasting several months the values of the iPTH-concentration in 7 of 8 examined patients were significantly lower than before this therapy. The results cited prove that by means of a wash with high calcium content the increased PTH-secretion may be diminished in patients with chronic renal insufficiency.

[Parathyroid hormone and 25-hydroxycholecalciferol concentrations in the serum of patients with kidney transplantations and their radiological correlation]. / Parathormon- und 25-Hydroxycholekalziferol-Konzentrationen im Serum nierentransplantierter Patienten und ihr röntgenologisches Korrelat.

In 40 renal transplant patients the serum concentration of parathyroid hormone, 25-hydroxycholecalciferol, calcium and inorganic phosphate were estimated. The results of these biochemical studies were compared to X-ray soft tissue and bone pathologic findings. The serum immunoreactive parathyroid hormone (iPTH) was normal in 37 patients and increased in 3 cases. 19 (47.5%) renal transplant recipients showed decreased serum 25-hydroxycholecalciferol levels. In 23 out of 40 patients (57.5%) serum phosphate was lower than 3.0 mg/100 ml. X-ray soft tissue changes were observed in 28 (70%) and bone changes in 18 (45%) patients; both frequencies were higher when compared to occurrence during regular dialysis treatment. Features of hyperparathyroid osteopathy were frequently observed in renal transplant recipients. Femoral head necroses were predominant in men, whereas osteomalacia with Looser's zones were found mainly in women. The pathogenesis of X-ray bone changes in patients with renal transplants seems to be multifactorial and related to the duration of secondary hyperparathyroidism before renal transplantation as well as to phosphate depletion and 25-hydroxycholecalciferol deficiency.

Serum 25-hydroxyvitamin D in patients with chronic renal failure on long-term treatment with high doses of vitamin D2.

The present study was aimed at answering the following two questions: (1) What is the effect of high dose vitamin D treatment on the serum level of 25-hydroxyvitamin D (25-OH-D) in patients with chronic renal failure (CRF)? (2) Is there any effect of urinary protein loss on the serum 25-OH-D levels during treatment with pharmacological doses of vitamin D? 42 patients with CRF were studied. They were treated conservatively by a low protein diet and received 15 mg of vitamin D2 once a week. Long-term administration of vitamin D caused a significant (5- to 7-fold) increase of plasma 25-OH-D level irrespective of the degree of proteinuria. This increase was noted only during the first 5 months of vitamin D2 treatment. Surprisingly only in some patients moderate hypercalcemia (> 2.75 mmol/l) was found. From the results obtained it is concluded that (1) patients with CRF differ from normal subjects in handling of high doses of vitamin D and (2) high dosage treatment with vitamin D may prevent hypocalcemia in patients with CRF in spite of high proteinuria.

Studies of vitamin D deficiency in man.

Highly sensitive assays have been developed that enable 25-hydroxycholecalciferol (25-hydroxyvitamin D3) and 25-hydroxyergocalciferol (25-hydroxyvitamin D2) to be measured in the same serum sample. With these assays it has been shown that endogenously produced cholecalciferol (vitamin D3) is important in man; the findings further emphasize the role of vitamin D metabolites as hormones rather than vitamins in the traditional sense. Dietary sources of vitamin D appear to be inadequate and vitamin D deficiency has been shown to the cause of rickets and osteomalacia in Asian immigrants to Britain. This condition may be readily treated with small doses of vitamin D. In addition, sub-clinical deficiency was found in the Asian community. In the elderly, also, vitamin D deficiency was established as an important cause of osteomalacia and again evidence for the existence of a sub-clinical deficiency state was found. It is therefore suggested that the present prophylactic practices should be reviewed. Secondary hyperparathyroidism (reflected by elevated concentrations of circulating immunoassayable parathyroid hormone) was shown to be the rule rather than the exception in vitamin D deficiency. Some patients, however, had failed to respond to a hypocalcaemic stimulus. In others, there were high concentrations of parathyroid hormone despite normal serum calcium concentrations. Thus the relationship between parathyroid hormone and metabolites of vitamin D may not be mediated through changes in serum calcium alone, and it is postulated that metabolites of vitamin D may directly affect the secretion of parathyroid hormone.

Prevention of vitamin-D deficiency in Asians.

Asian families living in Glasgow were studied between December, 1973, and June, 1974. One group of families served as a control; their mean serum-25-hydroxy-vitamin-D (25-hydroxy-cholecalciferol and 25-hydroxyergocalciferol) remained low, being 5-1 +/- 0-8 (S.E.M.) ng/ml at the end of the study. A second group was given 3000 units of vitamin D2 in a capsule weekly; this raised the mean concentration of 25-hydroxy-vitamin-D to 18-1 +/- 2-9 ng/ml. The variable effectiveness of this supplement was attributable to some subjects not taking the capsules regularly. The third group of families was provided with chupatty flour fortified with vitamin D(6000 units per kg). This increased mean serum-25-hydroxy-vitamin-D very uniformly to a mean value of 19-5 +/- 1-2 ng/ml. It is concluded that vitamin-D deficiency in Asian immigrants could be substantially reduced by fortification of chupatty flour with vitamin D.

Clinical and subclinical vitamin D deficiency in Bradford children.

A survey of the vitamin D status of Bradford schoolchildren was carried out in April 1973, employing conventional biochemistry, radiology, and measurement of 25-hydroxycholecalciferol levels. Biochemical evidence of rickets was present in 45% of the Asians. When re-examined in September, several children showed spontaneous biochemical resolution; nevertheless, radiological abnormalities were present in 12% of the original sample. No evidence of rickets was detected in the smaller White sample. Minor biochemical abnormalities were present in 9 of the 40 West Indian children. A study of admissions of Bradford hospitals in the 4 years 1969-1972 inclusive confirmed that clinical vitamin D deficiency was confined to Asians except for a few cases of infantile rickets in White children. The probability that one Asian child in 40 may require admission during the period from birth to adolescence emphasizes the urgent need for the introduction of prophylactic measures.