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Biomedical subjects

T Hisada

Publications and source records attributed to T Hisada.

At least 73 records · Page 4Linked to original sources
PubMed1976

[Metabolism of synthetic corticosteroid esters in man (author's transl)].

Metabolism of water-soluble synthetic corticosteroid esters, hydrocortisone hemisuccinate (H-H); hydrocortisone phosphate (HP), prednisolone hemisuccinate (P-H), prednisolone phosphate (P-P), dexamethasone phosphate (D-P) and dexamethasone sulfate (D-S) was studied by i.v. administration of steroids in a dose of 100 mg to 6 healthy volunteers and consequtive urine collections over 24 hrs. Uniary metabolites were separated into free, glucuronide, sulfate and "unhydrolyzed" fractions and measured by means of Porter-Silber (P-S) reaction and isonicotinic acid (INH) reaction. In H-H, H-P and D-S, glucuronide conjugates constituted the largest fraction of P-S positive metabolites in 24 hr-urine. In contrast, P-H, P-P and D-P were excreted mainly as free metabolites. Small but variable portions were found as sulfate and "unhydrolized" conjugates. Time course study revealed that, in H-H, H-P and D-S, the free/glucuronide ratio of P-S positive metabolites decreased progressively or remained low throughout the collection periods, whereas in P-H, P-P and D-P the ratio increased markedly in the 4--12 hr period. For all steroids, the INH/P-S ratio was found to be high in the free fraction and low in the glucuronide fraction; the tendency was especially marked in P-H, P-P and d-p. INH-positive metabolites were also predominant in the sulfate and "unhydrolyzed" fractions. The results indicate that the metabolism of synthetic corticosteroids, in general, is characterized by diminised rate of ring A reduction followed by glucuronide conjugation and compensatory increase in free metabolites, the bulk of which consists of ring A intact, C-20 reduced metabolites. 6-Hydroxylated metabolites may also be increased. Conjugation with sulfuric acid occurs but to a small extent. The consistent presence of "unhydrolyzed" metabolites suggests that portions of esters can be excreted unsplitted. It is also noted that the structure of steroid moieties and type of esters were important factors determining the quantitative and qualitative difference in their metabolic fates.

Dexamethasone↗
PubMed1976

Growth hormone and cortisol responses to psychological stress: comparison of normal and neurotic subjects.

The mirror drawing test (MDT) was performed to induce acute psychological stress in 9 normal controls and 10 neurotic subjects. Plasma growth hormone (GH) and cortisol were determined serially before, during, and after the test. In controls the MDT caused no significant change in plasma GH level, while in neurotics plasma GH increased progressively following the test. The increase of cortisol also tended to be greater in neurotics as a group, but there was considerable overlap in individual responses. The maximum increments of GH in neurotics correlated inversely with those of cortisol. The results indicate: 1) effective psychological coping mechanisms operate in normal man to keep the hormonal response minimum. 2) GH response is a more adequate indicator than cortisol response to psychological stress in neurotics. 3) GH and cortisol may have different psychological correlates in neurotics.

Adult↗
PubMed1976

[The adhesion of culture cells to some polymers (in vitro)].

Mouse L fibroblasts were grown on such plastic coated coverslips as polyvinyl acetate, cellulose, polymethylmethacrylate, polystyrene and polyvinyl alcohol in in vitro condition, in order to investigate cell contact to various polymeric substrata. Rates of cell multiplication in the presence of the plastics were obtained at the beginning of the experiments, the 2nd day, the 4th day and the 7th day of incubation. Morphological observation in the presence of the plastics were made for 14 hours. Rates of cell multiplication showed no change between most of the experimental groups, i.e., polyvinyl acetate, cellulose, polymethylmethacrylate and polystyrene and control, except polyvinyl alcohol. The cells were deterred from growing with polyvinyl acetate and completely deteriorated on the 4th day of incubation and thereafter. Morphological examination of the adhesion of culture cells to the polymers was made with an arbitrary classification of cell shapes such as round, bipole, spindle or star, depending upon the forms which the cells showed on the substrata under a light microscope, State of adhesion of the cells is considered to be increased in the ascending order of the four classification, polyvinyl acetate was the best in terms of cell adhesion, followed by cellulose, polymethylmethacrylate and polystyrene. The cells did not develop into the advanced state of adhesion in the presence of polyvinyl alcohol. As plastics have become one of the most important biomaterials in recent years, research on biocompatibility of the material, which can be represented by ascertaining of non toxicity, non irritability or non carcinogenecity and adhesion characteristics, is needed. Information on the above would surely be useful in better use of the material and also in developing new materials.

Cell Adhesion↗