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Biomedical subjects

Y Ichikawa

Publications and source records attributed to Y Ichikawa.

At least 703 records · Page 39Linked to original sources
PubMed1985

Binding capacity of sex-hormone-binding globulin and free testosterone determination in evaluation of hirsute women.

To investigate the relation between free testosterone (T) and binding capacity of sex-hormone-binding globulin (SHBG-BC) and a degree of hirsutism, 34 women were classified into 3 groups according to the criteria of Ferriman and Gallway on the degree of the hirsutism; 11 patients with a total score of 1 to 3 (group 1), 8 patients with a total score of 4 to 10 (group 2), and 15 patients with a total score of 11 or more (group 3). Total plasma T, SHBG-BC, and free plasma T were measured in each group, and they were compared with those of controls. In groups 1 and 2, mean levels of total T were slightly higher than in controls but the differences were not significant. Total T levels were extremely elevated in group 3. Mean level of SHBG-BC in group 1 was slightly lower than in controls but was not statistically significant. SHBG-BC was drastically reduced in groups 2 and 3. The percent free T levels and free T concentrations were significantly higher than those of controls in groups 2 and 3, but not in group 1. The results suggested that decreased SHBG-BC and increased free T might be the cause of hirsutism in women with normal total T levels.

Amenorrhea↗
PubMed1985

[Changes in % free testosterone and sex-hormone binding globulin during danazol administration].

To clarify the androgen balance on the administration of danazol a study was conducted on the levels of % free testosterone (% free T) and sex-hormone-binding globulin (SHBG) during the therapy and the binding properties of danazol to SHBG and androgen receptor. It was found that danazol displaced testosterone (T) from SHBG and R1881 from androgen receptor, in vitro. During treatment with danazol, levels of % free T were increased about three fold, but in contrast the SHBG concentration were significantly decreased. Similar changes in % free T were observed by computer simulation. These data suggest that the androgenic effects of danazol were the results of increased free T levels by the T-displacing ability of danazol from SHBG. The concentration of SHBG might be reduced as a consequence of increased levels of free T. On the other hand, danazol binding to androgen receptor might partially inhibit the action of excess amounts of free T, because the androgenization during therapy was too weak to compare the levels of free T.

Computers↗
PubMed1984

Modification of a lysine residue of adrenodoxin reductase, essential for complex formation with adrenodoxin.

The NADPH-cytochrome c reductase activity of NADPH-adrenodoxin reductase from NADPH to cytochrome c via adrenodoxin was inhibited by pyridoxal 5'-phosphate and other reagents that modified the lysine residues. However, the NADPH-ferricyanide reductase activity was not affected. Loss of the cytochrome c reductase activity could be prevented by adrenodoxin, but not by NADP+. One lysine residue of the adrenodoxin reductase could be protected from the modification with pyridoxal 5'-phosphate by complex formation with adrenodoxin. Loss of the NADPH-cytochrome c reductase activity was not due to the conformational change of the modified adrenodoxin reductase, judging from circular dichroism spectrometric studies.

Adrenal Cortex↗
PubMed1984

The influence of strenuous muscle stimulation on the menarche.

Nowadays, the average age at which menarche begins is lowering by three to four years every century, that is, four months every decade, according to both Japanese, and European and American annual changes of the average age. It emerged that the menarche shows a tendency to occur later in female gymnasts, because of the influence of strenuous muscle stimulation, and the fact that a higher level of technic is required in gymnastic games each year. These conclusions have been drawn from replies submitted to a questionnaire distributed among a relatively small number of gymnasts who participated in the competitions including the Inter High School Championship and the World Cup Championship. For example, at the age of 14, the percentage of women who had menstruated is almost 100% among women in general, but only 24% among World Cup Championship gymnasts, the average age at menarche of the latter being later than that of the former by as many as 3 years. At the age of 16, the percentage of women who had menstruated is 100% among women in general, but on the other hand, it is only 60% among World Cup Championship gymnasts, in other words, only a low percentage of women, of the latter group, had menstruated. Finally in our study, we established that the age at menarche of gymnasts is three or five years later than that of women in general. From our study, we concluded that the excessive burden imposed on muscles might cause an abnormal menstrual cycle, and the influence on menstruation would be considerable.

Adolescent↗
PubMed1984

Organ-specific properties of cytochromes P-450s21 (steroid 21-hydroxylases) of liver and adrenocortical microsomes.

Organ specificities of cytochrome P-450s21 (steroid 21-hydroxylase) were investigated. The substrate specificity of the liver cytochrome P-450s21 was found to be different from that of adrenocortical cytochrome P-450s21. The steroid 21-hydroxylase activity of liver microsomes decreased with treatment by sodium phenobarbital or beta-naphthoflavone and was inhibited by anti-cytochrome b5 immunoglobulin, although that of adrenocortical microsomes was not. The liver cytochrome P-450s21 was immunochemically similar to adrenocortical cytochrome P-450s21. The bovine liver and adrenocortical cytochromes P-450s21 showed immunoprecipitin lines against antibody to bovine adrenocortical cytochrome P-450s21. The molecular masses of the bovine liver and adrenocortical cytochromes P-450s21 were 60 +/- 1 and 50 +/- 1 kDa, respectively. The content of cytochrome P-450s21 and its percentage for the total microsomal cytochrome P-450 were immunochemically determined using the antibody to the bovine adrenocortical cytochrome P-450s21.

Adrenal Cortex↗
PubMed1984

J chain-positive cells in bursectomized chicks.

Using embryonic chickens treated with testosterone propionate, the effects of congenital absence of the bursa of Fabricius determined by the frequency of J chain-positive cells was examined in the spleen, thymus and bone marrow at the embryonic and newly hatched stages. J chain-positive cells in the chicks without bursa were reduced in the spleen. No differences in the numbers of the cells were detected in the thymus and bone marrow. These results imply that removal of the bursa of Fabricius cannot entirely prevent the generation of J chain-positive B cells. Furthermore, these results partly suggest the important role of the bone marrow in the proliferation of some J chain-positive cells in chicks without bursa.

Animals↗
PubMed1984

Behçet's syndrome: immune regulation, circulating immune complexes, neutrophil migration, and colchicine therapy.

Immune regulatory dysfunction, circulating immune complexes (CIC), and polymorphonuclear (PMN) cell migration were investigated in patients with Behçet's syndrome. Six patients meeting rigorous clinical criteria were evaluated. Only one patient showed evidence of immune regulatory dysfunction (increased T4/T8 ratio). Although C1q binding and Raji cell assays for CIC yielded positive results in only one of five patients, all five patients had in vivo "histamine trap test" evidence of CIC (all controls had normal results). Sera from all Behçet's syndrome patients increased migration of neutrophils to zymosan-activated serum. Colchicine therapy abolished the enhancing effect of the patient's sera on movement of PMN cells from patients and controls. An immune complex-mediated injury that is followed by an excessive accumulation of PMN cells may lead to the cutaneous lesions and other lesions in Behçet's syndrome. Further evaluation of colchicine therapy is warranted on the basis of these studies.

Adult↗
PubMed1984

The immunosuppressive mode of action of mizoribine.

Mizoribine (MIZ) suppressed the mitogen response and mixed lymphocyte reaction (MLR) significantly at doses of 100 micrograms/ml and 10 micrograms/ml in a dose-response analysis. The 50% inhibition dose (ID50) was between 10 micrograms/ml and 1.0 microgram/ml, both in the mitogen response and MLR. In a kinetic study of the MLR, the degree of suppression with MIZ at a given dosage was essentially the same as the degree of suppression observed in the dose-response analysis when MIZ was added to MLR cultures from day 0 to day 4. In addition, MLR was more susceptible to the suppressive activity of MIZ at 100 micrograms/ml when MIZ was added near the peak of lymphocyte proliferation. This experiment also showed that MLR suppression induced by MIZ at 10 micrograms/ml was reversible and MLR activity had completely recovered 6-8 hr after its removal. MIZ had no inhibitory action on MLR-derived cytotoxic cells or the effector phase of cell mediated lymphocytotoxicity. These results clearly demonstrate that MIZ suppresses lymphoproliferation, but has no effect on the recognition phase or effector phase of cytotoxic lymphocytes.

Dose-Response Relationship, Immunologic↗