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Biomedical subjects

T Obara

Publications and source records attributed to T Obara.

At least 289 records · Page 16Linked to original sources
PubMed1978

Enzyme-linked immunoassay of somatostatin.

An enzyme-linked immunoassay for somatostatin using somatostatin-alkaline phosphatase conjugate as "labeled" antigen was developed. Minimal detectable dose at present was 40 pg per tube. Serial dilutions of rat hypothalamic extract gave a gradual change of antibody-bound alkaline phosphatase activity which was parallel to that with standard somatostatin. Precision and accuracy of the method were comparable to those in radioimmunoassay reported by others. This method will be a useful tool for the determination of somatostatin, especially in tissues.

Alkaline Phosphatase↗
PubMed1977

Medullary thyroid carcinoma and pheochromocytoma accompanied with nodular hyperplasia in multiple endocrine neoplasia type 2.

Three patients with familial multiple endocrine neoplasia type 2 underwent total adrenalectomy and subsequently near-total or total thyroidectomy. The overt pheochromocytomas were present bilaterally in two patients and unilaterally in another patient. In addition, multiple nodules measuring a few mm in diameter were demonstrated in all adrenal medullas examined. All patients exhibited bilateral medullary thyroid carcinomas which varied in size from a few minute nodules accompanied by the microscopic C-cell hyperplasia to distinct large tumors. The thyroid C-cell hyperplasia appeared to be confined to the upper and middle thirds of the lateral lobe, and micronodules of the C-cell hyperplasia enlarged to coalesce, forming one large carcinoma mass. On the other hand, nodular hyperplasia of the chromaffin cells was distributed diffusely throughout the adrenal medulla and each nodule appeared to develop individually into a large pheochromocytoma. These findings suggested that, at least in the family members at a high risk for multiple endocrine neoplasia type 2, the development of both medullary thyroid carcinoma and pheochromocytoma was always preceded by a multicentric nodular hyperplasia. On the basis of the pathogenesis of these tumors, the most rational surgical approach was presented.

Adrenal Gland Neoplasms↗
PubMed1977

Failure of growth hormone-suppressing agents to affect TSH-releasing hormone- and LH-releasing hormone-induced growth hormone release in acromegaly.

In patients with acromegaly whose basal plasma GH levels were suppressed with 9 mg/day of dexamethasone for 2 days, TRH-(6 cases) and LHRH-(1 case) induced GH release were unaffected when the responses were compared to the basal levels. Phentolamine infusion, 70 mg in 150 min, or hyperglycemia induced by iv infusion of 700 ml of 50% glucose solution also did not suppress TRH-induced GH release in 2 acromegalic patients whose basal GH levels were lowered with these agents alone. These results seem to indicate that dexamethasone does not affect TRH- or LHRH-induced GH release per se, but affects the basal state which determines the absolute level of response. They also support the concept that TRH and LHRH act directly on pituitary tumor cells to release GH in acromegaly.

Acromegaly↗
PubMed1976

Suppression of plasma growth hormone levels with glucose infusion in patients with acromegaly.

Intravenous glucose infusion which increased blood glucose levels over 27-8 mmo1/1 suppressed plasma GH levels by 41-74% in five acromegalic patients with basal concentrations of less than 20 mu/1, but not in six patients with basal levels over 80 mu/1. Oral 100 g glucose loading had little suppressing effect in both groups. These results appear to indicate that the suppressibility with hyperglycaemia is partially retained or restored in some, if not all, patients of acromegaly with lower GH secreting activity.

Acromegaly↗
PubMed1976

The effects of dietary sodium on the diurnal activity of the renin-angiotensin-aldosterone system and the excretion of urinary electrolytes.

Diurnal variations of five normal men were tested over three 24 h consecutive periods. The first experiment began at 0900 h after the subjects had fasted for 12 h and a normal sodium diet of about 70-80 mEq was given at 0900 h, 1200h, and 1630 h (total of about 220 mEq of Na). Significant variations in the plasma renin activity (PRA), in the plasma aldosterone (PA), and in the urinary Na and K outputs were found. The second experiment began at 1200 h with the first feeding time at 2100 h after fasting about 24 h and the subjects were given a normal sodium diet as in the first experiment, but with the meals given at 2100 h, 2400 h, and 0430 h. The diurnal variations in PRA, plasma aldosterone, and urinary electrolytes disappeared. From this study, it appears that the diurnal variation in urinary electrolyte excretion is a factor of the diurnal variation in PRA and plasma aldosterone. The diurnal variation in PRA and plasma aldosterone are related to the timing of sodium ingestion.

Adult↗
PubMed1976

[Efficiency of heat exchanging equipment in a laboratory animal facility (author's transl)].

The efficiency of the so-called econovent heat exchanging equipment located in the Institute of Laboratory Animal Sciences, Faculty of Medicine, Kagoshima University, was measured as follows: The air velocity was decreased to about 64% of that with the fresh air ducts, but a sufficient air volume was supplied maintaining an air change of 12 times per hour or more. The efficiency of the econovent showed a little difference depending upon air conditioning systems. The average efficiencies were 81%, 75% and 76% for temperature, absolute humidity and enthalpy, respectively. The energy required for the air conditioning in this facility in September 1975 and January 1976 estimated by enthalpy hour almost agreed with that estimated using a calorie meter or steam meter. It was assumed that a total of 63% and 60% energy were saved in the cooling and heating seasons, respectively, using the econovent.

Air Conditioning↗
PubMed1975

Physical and radiological findings specific for medullary carcinoma of the thyroid gland.

Preoperative physical and radiological findings, if specific to a certain extent, are important for detecting patients with sporadic form of medullary thyroid carcinoma and especially for the first patient in the family having a hereditary form of medullary thyroid carcinoma and pheochromocytoma syndrome. To delineate clinical features of medullary thyroid carcinoma, a total of 9 patients with this tumor were reviewed retrospectively. In most patients, the thyroid lesions were located in the upper two thirds of the lobe, which was determined by careful palpation or 131I scintiscanning of the thyroid. The primary lesion in the thyroid could be felt more or less as a round, sharply demarcated nodule with fairly good mobility. These findings suggested rather a benign thyroid nodule when there was no lymph node involvement. However, it could be considered a sign suggesting medullary thyroid carcinoma when accompanied by marked lymph node metastasis. In our recent 2 cases, the diagnosis of medullary thyroid carcinoma was strongly suspected on these clinical bases, one of the cases being presented in detail. In 4 patients, lymph node metastasis in the central neck extended to either submandibular or upper mediastinal regions or both. In about one third of the patients, calcified deposits were shown in the cervical roentgenograms. With the use of soft tissue roentgenography, grossly punctate calcific deposits associated with psammoma-like shadows were recognized and the pattern was a criterion for definitive diagnosis of medullary thyroid carcinoma.

Adult↗