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Biomedical subjects

H Yoshimoto

Publications and source records attributed to H Yoshimoto.

At least 163 records · Page 9Linked to original sources
PubMed1980

Studies on the angioarchitecture of the posterior choroid in rat and role of posterior ciliary vein.

Vascular casts were made by injection of low-viscosity plastic in eight Wistar-Kyoto rats, and the posterior half of the ocular wall was observed using the semiultrathin section method. Veins which connect with the capillaries of the posterior choroid include a venous system independent of the cortex vein and running parallel to the long and short posterior ciliary arteries. The veins flow into a venous ring which is located in the region at which the arterial circle of Zinn is said to be. There was no structure in this region which could be described as an arterial circle. From the above findings, it is concluded that these venous systems are part of the posterior ciliary vein and that they play an important role as a pathway for irrigation of blood from the posterior choroid.

Anatomy↗
PubMed1979

Effect of a single dose of glucocorticoid on the diurnal variations of TSH, thyroxine, 3,5,3'-triiodothyronine, 3,3'5'-triiodothyronine and cortisol in normal men.

Plasma thyrotropin (TSH) and cortisol concentrations were suppressed immediately after an intravenous bolus dose of 8 mg betamethasone in 6 male subjects. The circadian variations of these hormones disappeared for 40 hr (TSH) and 44 hr (cortisol). Plasma thyroxine (T4), 3, 5, 3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (reverse T3) levels did not show diurnal variations before betamethasone administration. Plasma T3 levels decreased to 66% of the basal levels 20 hr after batamethasone administration, whereas plasma reverse T3 levels increased to 163% of the basal levels at 24 hr. These changes were reversed by 3 to 5 days after betamethasone. The earlier recovery of the diurnal rhythm of TSH than that of cortisol suggests that the TSH rhythm is not under the direct control of circulating cortisol.

Adult↗
PubMed1977

[Clinical evaluation on glucocorticoid administration in the neurosurgical patients (the third report)--serial plasma cortisol assay following betamethasone 8 mg intravenous injection (author's transl)].

The effect of betamethasone on plasma cortisol concentrations was studied in 6 healty adult men. Each of them was administered 8 mg of betamethasone in a single intravenous injection. Blood samples were obtained serially for 2 days before the injection of betamethasone and for a week after the injection. Plasma cortisol was measured by competitive protein binding analysis. Before the injection of betamethasone plasma cortisol levels showed the normal diurnal rhythm in all the cases. After the injection plasma cortisol levels decreased rapidly and a mean half life time was about 1.7 hours. The low levels of plasma cortisol under 2 microgram/ml were observed for 48 hours after the injection, and then the diurnal rythm of plasma cortisol reappeared, but the levels of plasma cortisol at this time were still lower than the control levels. Then plasma cortisol levles increased gradually and they returned to the control levels 5 days after the injection. Thus, it was clarified that the suppressive effect of 8 mg or betamethasone on plasma cortisol concentrations lasted at least for 48 hours. From this point of view the time interval or repetitive glucocorticoid administration for the treatment of brain edema will further be studied.

Adult↗
PubMed1977

[Endocrinological evaluation of sellar and suprasellar tumor cases (the ninth report)--on the PRL levels in the CSF (author's transl)].

Prolactin (PRL) levels in the cerebrospinal fluid (CSF) and plasma of 25 patients with sellar and suprasellar tumors, i.e. 5 of PRL secreting adenoma, 5 of GH secreting adenoma, 7 of so-called non-functioning pituitary adenoma, 5 of tuberculum sellae meningioma and 3 of craniopharyngioma, were studied in relation to the size of suprasellar extension measured by our own method on pneumoencephalograms. Plasma and CSF samples were obtained simultaneously at the time of lumbar puncture for pneumoencephalography. 1) Five patients of PRL secreting adenoma, whose plasma PRL levels ranged from 530 to 4,000 ng/ml, showed high PRL levels over 50 ng/ml in the CSF. On the contrary, 20 patients of the other tumors, whose plasma PRL levels were lower than 30 ng/ml, showed low PRL levels in th4 CSF, being below the sensitivity limit in the majority. 2) In 3 out of 5 PRL secreting adenomas, the PRL level in the CSF was higher than the plasma level and they showed a fairly large extrasellar extension. However in the remaining 2 the PRL level in the CSF was lower than a tenth of that in the plasma, and these revealed relatively small suprasellar extension. From these facts the presence of PRL at a high level in the CSF seems to be specific in the PRL secreting adenomas, and there seems to be a relationship between the CSF-plasma ratio of PRL level and the extrasellar extension in these cases.

Adenoma↗