Biomedical subjects
Publications and source records attributed to G Offermann.
Oxalosis, a rare metabolic disorder, leads to excessive formation of oxalate and deposition of calcium oxalate crystals in the tissue. This leads to renal insufficiency with resulting secondary hyperparathyroidism and myelofibrosis. In a 27 year old female patient, extensive destruction of the maxilla, mandible and teeth was observed which has not yet been described and which led to the loss of all teeth.
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In an adult with sporadic idiopathic osteomalacia an increased phosphate clearance, hypophosphataemia, normocalcaemia, normal serum-25-hydroxycalciferol and an only slightly increased immunoreactive parathormone were found. Intestinal 47Ca absorption was clearly decreased. Radiologically and histologically there was a clear-cut defect of skeletal mineralisation. Under treatment with daily doses of 1-1.25 mg of vitamin D3 the 25-hydroxycalciferol level increased markedly, the immunoreactive parathormone decreased slightly. Serum calcium and hypophosphataemia remained unchanged and intestinal 47Ca absorption was improved. Already 4 weeks after commencing treatment pain and defective gait of the patient disappeared. Radiologically skeletal changes were improved after 7 months. However, histologically no significant bone healing had occurred. The biochemical findings of this disease correspond to those of familial hypophosphataemic (vitamin-D-resistant) rickets. The therapeutic effects of pharmacological doses of vitamin D resemble those in pseudo-vitamin-D-deficient rickets. The pathogenesis of idiopathic osteomalacia of the adult remains unclear. Vitamin D metabolism is unchanged as far as the stage of 25-hydroxycholecalciferol. It is unknown if a disorder of the renal synthesis of 1,25-dihydroxycholecalciferol or a peripheral resistance to the effects of this metabolite exists. In addition a defect of the tubular phosphate reabsorption independent of parathormone and vitamin D is assumed.
Immunoreactive parathyroid hormone (iPTH) and 25-hydroxycalciferol (25(OH)D) serum levels were determined in 32 patients with renal osteopathy, they were correlated with the results of bone biopsy and other clinical parameters. iPTH was closely related to bone histology, it did not correspond to serum calcium and alkaline phosphatase, but the correlation to serum phosphate was statistically significant. 25(OH)D levels were not related to the histological findings of osteomalacia or increased bone resorption, while a correlation between the vitamin D metabolite and serum calcium could be observed. Since iPTH and 25(OH)D levels exhibited a significant correlation, an inhibitory effect of 25(OH)D on parathyroid gland function in renal failure was discussed.
Vitamin D analogues of high biological activity are probably useful in the treatment of renal osteodystrophy. The pharmacokinetics of the synthetic compound 5,6-trans-25-hydroxycholecalciferol have been studied in healthy subjects who were of normal vitamin D status. In comparison to natural 25-hydroxy-cholecalciferol, serum levels of the analogue were lower and its half-life in blood after oral or intravenous administration was considerably shorter. In normal subjects no increase of dihydroxylated metabolites in serum was observed within seven days of an intravenous dose.
The plant Solanum malacoxylon (S.M.) is known to cause severe soft tissue calcifications in cattle and sheep and has recently become of special interest since it exerts biological actions which resemble those of vitamin D. In order to investigate whether S.M. is capable to improve the rachitic bone changes in vitamin D and phosphate deficient rats, a watery extract of 50, 100 and 200 mg S.M. was fed daily to these animals over a period of 10 days. The width of epiphyseal plates was compared after the time with those of rats treates with 0, 0.225, 0.45, and 0.9 IU of vitamin D3 daily. There was a dose related curative effect of S.M. on the epiphyseal lesions very similar to that of vitamin D3. The hypercalcemic and hyperphosphatemic effect of S.M. was identical to that of vitamin D3. The 25-hydroxy-vitamin D serum levels remained almost undetectable in the S.M. treated rats as well as in the vitamin D3 treated animals.
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