[Vitamin D and the immune system].

The authors draw attention to the contemporary broad concept of the vitamin D endocrine system comprising in addition to the gut, bones and kidneys, some other tissues and cells incl. cells of the immune system. They give an account of findings on receptors for the active hormonal metabolite of vitamin D, 1,25-dihydroxycalciferol [1,25(OH)2D], in the cells of the immune system and summarized contemporary ideas on the mechanism of action of 1,25(OH)2D in these cells.

[Method for the determination of ionized calcium in clinical practice].

The authors give an account of their experience with the problem of assessment of ionized calcium (Ca2+) in clinical work. To assess Ca2+ they use an ICA 2 analyzer of Radiometer Co. Copenhagen which makes it possible to assess concurrently the Ca2+ concentration at a given pH (Ca2+/act.

Effect of 1,25-dihydroxycholecalciferol on fracture healing and on general posttraumatic skeletal response in rats.

The authors investigated the effect of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) on the local healing process following an artificial fracture of the rat tibia and on the general posttraumatic response of the skeleton to local trauma. The results showed a significant increase in dry weight of fractured tibias as compared with contralateral intact bones which was due to the newly formed callus. 1,25(OH)2D3 significantly increased the weights of tibias which can be explained by its stimulatory effect on callus formation.

[The role of aluminum-induced inhibition of the intestinal absorption of calcium in the pathogenesis of aluminum osteopathy].

The aim of the study was to investigate the effect of aluminium on duodenal calcium absorption, the impairment of which can represent a pathogenic factor in the development of aluminium bone lesions. The authors investigated in the chick the effect of Al(OH)3 administered orally and of AlCl3 administered subcutaneously on the duodenal absorption of 47Ca, on serum concentration of calcium, phosphorous, aluminium and 1,25-dihydroxycholecalciferol and on bone morphology. Oral administration of Al(OH)3 for 8, 15, and 22 days was without any significant change.