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Evidence has been accumulated that some phytoestrogens act as protective factors against development of cancer and also cardiovascular diseases. These are phytoestrogens of isoflavone and lignane series, found especially in soy. Beneficial effect of these compounds may be explained by a complexity of their actions at various levels: they interact with estrogen receptors, some of them are inhibitors of the key enzymes responsible in the final effect for cell growth and proliferation, and, due to their chemical nature they are scavengers of free radicals. In the presented work the authors, in collaboration with Finnish partners from the University of Helsinki, developed original immunoassays for determination of main phytoestrogens of isoflavone series--daidzein, genistein, formononoetin, biochanin A, their metabolite equal and lignane enterolactone. The methods are sensitive enough for follow-up of actual levels of phytoestrogens in serum. By using these methods, the levels of phytoestrogens in Czech population have been established. The group of patients suffering from osteoporosis has been investigated, too. Significantly lower levels of isoflavonoids in comparison with sex- and age-matched healthy subject have been found in the patients. The methods have also enabled us to follow up the dynamics of these compounds in the organism, as well as to determine their content in food and its sources. The original detection and quantification of four above mentioned isoflavonoids in beer is an example.

In a group of 47 women and 54 men with chronic renal failure included in a regular haemodialyzation programme the mineral content of bone was assessed using the method of radiation absorption of the radioisotope americium (241Am) on a Bone mineral detector of Gambro Co. The bone mineral content was reduced in men and women by 22%, as compared with healthy subjects of the same age and sex. The reduction was more marked in patients dialyzed for longer periods and when there were lamoratory signs of activity of the process.

In a group of 60 patients dialyzed for more than three years laboratory signs of aluminum accumulation were found in 30%. Serum Al values correlated with the increment in the desferal test. Orally administered aluminium hydroxide is a significant source of Al accumulation, as has been demonstrated by the decline of the blood aluminium level after its discontinuation and a negative desferal test in patients to whom it was not prescribed. The passage of Al across the dialyzation membrane depends on the difference between the ultrafiltrable ratio of the blood value and the Al concentration in the dialyzate. Therefore even a concentration of 10 micrograms/l Al in the dilyzate, so far recommended as "safe", can lead to a rise of the Al blood level during haemodialysis and to Al accumulation in tissues. Effective removal of Al from the organism is possible only during haemodialysis after previous administration of Desferal. Unless an adequate substitute of aluminium hydroxide will be available and a completely aluminium free dialyzate, Al accumulation can be prevented by preventive administration of Desferal.

The authors discuss the question of whether the growing blood concentration of beta-2-microglobulin in the course of haemodialysis is due to the bioincompatibility of the cuprophane membrane or to changes in serum osmolality. x531p4cuprophane dialyzer was used for 20 acts of haemodialysis, a regenerated one for 12, a new one for 10 sequence ultrafiltrations. The serum concentration of beta-2-microglobulin was measured prior to and after haemodialysis, and so was serum osmolality. The changes in beta-2-microglobulin concentration during haemodialysis were compared with serum osmolality changes. The levels of beta-2-microglobulin rose during haemodialysis using a new as well as a regenerated dialyzer but remained unaltered during sequence ultrafiltration. They increased in the presence of serum hypoosmolality, remained unchanged in normal osmolality, and decreased in hyperosmolality. The results show that the cuprophane membrane is not the source of increased beta-2-microglobulin, but that serum hypoosmolality developing during haemodialysis is the factor responsible.