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Biomedical subjects

Y Kazama

Publications and source records attributed to Y Kazama.

At least 55 records · Page 3Linked to original sources

Circulating prostacyclin and thromboxane in patients with Graves' disease.

We measured plasma levels of PGI2 as 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane A2 (TXA2) as thromboxane B2 (TXB2) in patients with Graves' disease and in normal subjects. The levels of plasma 6-keto-PGF1 alpha were significantly elevated and correlated with those of serum T4 and T3, respectively, in hyperthyroid patients with Graves' disease. Significant reduction of 6-keto-PGF1 alpha levels was observed after antithyroid drug therapy. In contrast, the levels of plasma TXB2 were significantly lower in untreated patients with Graves' disease than in normal subjects. These data suggest that an elevation of plasma 6-keto-PGF1 alpha may play some additional role in pathophysiology of Graves' disease.

6-Ketoprostaglandin F1 alpha↗

The effects of thyroxine and methimazole treatment on the synthesis of prostacyclin (PGI2) in the rat.

The effects of thyroxine (T4) and methimazole administration on plasma prostacyclin (PGI2) levels in vivo and on PGI2 release by aortic rings incubated in vitro were investigated in rats. Male rats were given single injection of T4 (200 micrograms/100 g body wt) ip every 24 h for either 3, 7 or 14 days for hyperthyroid rats. For hypothyroid rats, a group of rats were given methimazole (0.01 % in drinking water) for 14 days. PGI2 concentrations were determined in plasma and also in the medium in which aortic rings were incubated. PGI2 was measured as 6-keto-PGF1 alpha by RIA. Plasma PGI2 levels in T4-treated groups were found to be significantly higher than those of control animals. Aortic rings obtained from rats given single injection of T4 for 7 and 14 days showed significant increases in release of PGI2 into the incubation medium. In contrast, rats given methimazole for 14 days showed a significant decrease in the production of PGI2 by aortic rings without any significant changes in plasma levels. Direct addition of T4 into the incubation medium did not cause any significant changes in PGI2 release by aortic rings obtained from control rats. These results suggest the regulatory role of thyroid hormone in PGI2 synthesis in vivo.

6-Ketoprostaglandin F1 alpha↗

A case of Cushing's syndrome associated with possible adrenomedullary hyperplasia.

A 57-year-old male, who had been suffered from hypertension and diabetes mellitus for 10 years, was admitted to the hospital because of thirst, lassitude and muscle wasting. On admission, his urinary excretion of 17-OHCS and plasma cortisol levels were elevated without diurnal variations. Plasma ACTH levels were found to be very low with repeated determinations. Dexamethasone suppression test, 2 mg 4 times a day orally for 2 days, showed no changes in plasma cortisol levels and only a mild reduction in urinary 17-OHCS excretion. Estimation of urinary catecholamines showed an increase only in norepinephrine. Abdominal computerized tomography and radionuclide scanning of adrenal glands with 131I-adosterol demonstrated a well-defined adrenal mass in the left side without apparent changes in the right side. 131I-metaiodobenzylguanidine scintigraphy was negative. At surgery, his left adrenal medulla was found to be hypertrophic in addition to the cortical tumor. The left adrenal gland was also removed. After surgery, excretion of urinary catecholamines fell to nearly the normal range and he was discharged without insulin and antihypertensive drugs. Microscopically, the cortical tumor is an adenoma consisting of lipid laden cells and eosinophilic compact cells. Medullary cells were distinctly hyperplastic in appearance and many of the cells were extensively vacuolated, suggesting an active functional status. The present report describes a patient with Cushing's syndrome who showed increased urinary catecholamine excretion due to the possible coexistence of adrenal medullary hyperplasia. As far as we know, this is the first case of Cushing's syndrome with this abnormality.

Adrenal Medulla↗

Ruptured aneurysm of aortic sinus of Valsalva into right ventricle.

We report a patient with ruptured aneurysm of the aortic sinus of Valsalva into the right ventricle, whose heart murmur represented only a diastolic element without aortic regurgitation. Surgery revealed a small opening through myocardium of the ventricular septum without ventricular septal defect. During systole, the opening was constricted and presumably closed with myocardial contraction, and left-to-right shunt might have occurred only in diastole. This might lead to only a diastolic murmur.

Adult↗

Estimation of thyroxine and triiodothyronine distribution and of the conversion rate of thyroxine to triiodothyronine in man.

Studies on peripheral metabolism of simultaneously administered 125-I-labeled L-thyroxine ([125-I]T4) and 131-I labeled L-trilodothyronine ([131-I]T3) were performed in five normal subjects, in four patients with untreated hypothyroidism, and in 3 hypothyroid patients made euthyroid by the administration of T4. The fractional turnover rate (lambda 03) of thyroid hormones irreversibly leaving the site of degradation and the volumes of pool 1 (serum V1) of pool (interstitial fluid, V2), and of pool 3 (all tissues, V3)were obtained by using a three-compartment analysis. In addition to the turnover studies, the ratios for the in vivo T4 to T3 conversion were determined by paper chromatographic study in sera obtained 4, 7, and 10 daysafter the injection. The rate (K12) of the extrathyroidal conversion of T4 to T3 was also estimated by the compartment analysis. The T3 distribution volume (V3) of pool 3, in which T3 is utilized and degraded, was about 60% of totaldistribution volume (V=V1+V2+V3) in normal subjects, whereas only about 25% of the extrathyroidal T4 pool was in the intracellular compartment, indicating that T3 is predominantly an intracellular hormone..

Adult↗

[Werner's syndrome].

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17-Hydroxycorticosteroids↗