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Biomedical subjects

P Rodbro

Publications and source records attributed to P Rodbro.

At least 19 recordsLinked to original sources

The effect of different vitamin D treatments on serum vitamin D levels in early postmenopausal women.

The effects of vitamin D3 and 1,25 (OH)2D3 or l alpha-OHD3 on vitamin D metabolism were studied in a 12 month placebo controlled clinical study. 29 healthy women in their early menopause were randomized for treatment with either vitamin D3 (2000 IU/day, or 1,25(OH)2D3/l alpha-OHD3(0.25 micrograms/day), or placebo for 12 months. All participants were given a calcium supplement of 0.5 g/day throughout the study. Serum and urinary calcium increased in both vitamin D groups, whereas the posttreatment values in the placebo group were exactly the same as before treatment. Changes in the vitamin D metabolites only occurred in the vitamin D3 group, where 24,25(OH)2D and 25OHD3 were significantly increased, whereas the serum concentration of 1,25(OH)2D was unchanged. In the 1,25(OH)2D3/l alpha-OHD3 group no change in the serum vitamin D was found. The present data indicate that 1,25(OH)2D is subject to a tight feedback regulation; that 1,25(OH)2D is not the only vitamin D metabolite responsible for calcium absorption from the gut, and that 1,25(OH)2D given in physiological doses does not alter the metabolism of the other vitamin D metabolites.

Calcitriol↗

Minor influence of parathyroid hormone on fractional tubular reabsorption of phosphate in chronic renal failure.

In untreated patients with chronic renal failure and glomerular filtration rates (GFR) between 10 and 25 ml/min the decrease in fractional tubular reabsorption of phosphate was correlated to the degree of secondary hyperparathyroidism. This correlation was not found in patients with GFR below 10 ml/min. During treatment with 1alpha-hydroxycholecalciferol for 11 weeks: a) serum parathyroid hormone concentration decreased in all patients on average 60%, and was normal in 5 patients after treatment b) fractional tubular reabsorption of phosphate decreased significantly (on average 0.21) c) glomerular filtration rate decreased significantly (on average 27.5%). Since the reduction (or normalization) of serum parathyroid hormone concentration did not increase the fractional tubular reabsorption of phosphate, other (GFR-related) factors than parathyroid hormone play the major role for renal handling of phosphate in chronic renal failure when GFR is below 25 ml/min.

Biological Transport↗

Bone composition and parathyroid function in chronic renal failure.

The development of bone abnormalities has been studied in 24 patients with severe chronic renal failure. The glomerular filtration rate (GFR) was between 5 and 25 ml/min. The mean values of plasma calcium, degree of bone mineralization (P/Hypro) and bone mineral content (BMC) were subnormal, whereas the mean values of plasma phosphorus and serum parathyroid hormone (PTH) were elevated. Analysis of the data revealed that the various parameters became increasingly pathological with decreasing renal function. Serum PTH correlated inversely with both GFR and plasma calcium. The decrease in bone P/Hypro with decreasing renal function could be explained by an inverse correlation to serum PTH. Plasma alkaline phosphatase correlated inversely to both bone P/Hypro and BMC. The present study on individual patients with varying degrees of renal insufficiency shows that the development of secondary hyperparathyroidism correlates with a reduction in the degree of bone P/Hypro and suggests that significant bone changes appear when the GFR falls below 15 ml/min.

Adult↗

Bone changes during prednisone treatment.

To evaluate changes inbone composition during treatment with corticosteroids, the bone mineral content (BMC, measured by photon absorptiometry) and the degree of bone mineralization (measured as the bone phosphorus/hydroxyproline ratio) were determined in 18 patients during prednisone treatment for haematological and connective tissue diseases. The prednisone dose ranged from 12 to 51 mg/day (mean 27). The BMC decreased significantly (mean 2.5%) during the studied 12 weeks of treatment, but the change did not correlate significantly to the prednisone dose. The degree of bone mineralization remained unchanged, indicating equal losses of mineral and of collagen in bone during prednisone treatment. The changes correspond to a rapidly developing oesteoporotic state.

Aged↗

Bone mineralization and bone mineral content in primary hyperparathyroidism.

The degree of bone mineralization and the bone mineral content (BMC) was evaluated in 6 patients with primary hyperparathyroidism. The degree of bone mineralization was estimated as the phosphorus/hydroxyproline ratio (P/Hypro) in bone biopsies; BMC was estimated by photon absorptiometry on both forearms. The mena values of both parameters were significantly lower than normal (P less than 0.001 for P/Hypro; P less than 0.02 for BMC). As no significant correlation was found between P/Hypro and BMC in hyperparathyroidism, the findings of low values of P/Hypro and of BMC in patients with elevated serum calcium point to primary hyperparathyroidism.

Adult↗

Delimitation of plasma creatinine concentration values for assessment of relative renal function in adult patients.

Plasma creatinine concentrations and glomerular filtration rates (GFR) were determined simultaneously in 200 females and 180 males of various ages (20-79 years) covering all degrees of relative renal function: normal (greater than 75%); moderately impaired (75-52%); considerably impaired (51-28%); and severely impaired (greater than 28%). The percentages express GFR relative to corresponding age--and sex-dependent normal means. This relative parameter evaluates whether--and to what extent--the combined function of the two kidneys is affected by nephro-urological disorders. For practical purposes plasma creatinine was found to be independent of age in all function groups for both sexes. The data were used to delimit plasma creatinine concentrations for the assessment of relative renal function. For females the limits of plasma creatinine (mumol per litre) were: "normal" (less than 115); "moderately elevated" (115-150); "considerably elevated" (151-250); and "profoundly elevated" (greater than 250). The corresponding figures for males were: less than 128; 128-170; 171-270; and greater than 270.

Adult↗

Controlled trial of 1apha-hydroxycholecalciferol in chronic renal failure.

24 patients with chronic renal failure (glomerular filtration-rate (G.F.R.) 5-25 ml/min) participated in a double-blind placebo-controlled trial of the effects of 1 alpha-hydroxycholecalciferol (1alpha-H.C.C.) 1 mug daily for eleven weeks. This treatment induced significant increases in the intestinal absorption of calcium and in plasma-calcium which reached normal levels within two weeks. It also induced a significant reduction of the raised serum levels of parathyroid hormone. No significant changes were induced in plasma-phosphorus, plasma-alkaline-phosphatase, or in the degree of bone mineralisation as measured by the phosphorus/hydroxyproline ratio in bone. The bone mineral content in the forearm measured by photon absorptiometry decreased to the same extent in the 1alpha-H.C.C. groups and in the placebo group. The fall in G.F.R. over eleven weeks was 2-5 times greater in the 1alpha-H.C.C. group than in the placebo group, but this difference was not significant. It is concluded that 1alpha-H.C.C. treatment in chronic renal failure does not affect the progressive loss of calcium from bone despite normalisation of plasma-calcium.

Adult↗

A comparison of two methods for estimating bone loss.

The presence or absence of osteopenia, as judged by routine X-ray examination of the lumbar spine supplemented by X-ray evaluation of calcaneus, has been investigated in 73 female subjects who also had photon absorptiometry done on calcaneus and antebrachiúm. Comparison of the two methods reveals that there is no close relationship between the results. Photon absorptiometry for evaluating bone mineral content has proven its precision and accuracy, while conventional X-ray film evaluation of bone mineral seems to lack a proper foundation.

Absorptiometry, Photon↗

Unchanged total body calcium in normal human pregnancy.

The total body calcium--estimated from bone mineral content in the distal part of the forearm measured by use of photon absorptiometry--was determined during pregnancy in 13 women. The results indicate that total body calcium is constant during pregnancy.

Adult↗

Skeletal status in patients with chronic renal disease.

The bone mineral content (BMC) was measured in 17 patients with chronic renal failure. The patients as a group had a mean BMC of 89% compared with 127 normal subjects. The investigation failed to disclose any significant correlation between BMC and the stage of renal diseases.

Adult↗