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Biomedical subjects

T Obara

Publications and source records attributed to T Obara.

At least 253 records · Page 14Linked to original sources
PubMed1985

Surgical treatment of secondary hyperparathyroidism in patients with chronic renal failure: reevaluation of indications for parathyroidectomy.

On reviewing the preoperative clinical and laboratory findings and the surgical response seen in our series of 32 patients with renal hyperparathyroidism, the indication for parathyroidectomy was reevaluated. During the 5-year period from 1975 to 1979, parathyroid resection was performed in 9 patients who had various conditions for which surgery had been thought indicated. During the following period from January 1980 to March 1985, parathyroidectomy was carried out on 23 patients all of whom had roentgenologic evidence of generalized fibrous osteitis except for two whose indication for surgery was an elevation of the serum alkaline phosphatase level more than 45 KA units. The resected parathyroid glands had increased to 1 g or more in total weight in all the 25 patients who showed distinct postoperative improvement. Laboratory evidence indicating the presence of generalized fibrous osteitis, such as subperiosteal resorption on phalanx roentgenograms and high serum alkaline phosphatase level, along with marked elevation of the plasma immunoreactive parathyroid hormone level, proved to be a good indicator for medically uncontrollable secondary hyperparathyroidism. Fracture, heterotopic calcification, pruritus or persistent hypercalcemia was not a parameter of severe hyperparathyroidism warranting parathyroid resection, unless there was concomitant evidence of fibrous osteitis. The preoperative use of the recently developed noninvasive techniques for parathyroid localization also proved to be useful in detecting the parathyroid glands large enough to fulfill the requirements for parathyroidectomy.

Adult↗
PubMed1984

Cholesterol side-chain cleavage activity in the outer and inner zones of the adrenal cortex.

Cholesterol side-chain cleavage activity in mitochondria isolated from the outer and inner zones of the guinea pig adrenal cortex was evaluated in order to clarify the role of the zona reticularis in steroidogenesis. It was found that side-chain cleavage activity was three times higher in the outer zone. In addition, ether stress increased side-chain cleavage activity in the outer zone but not the inner zone. The concentration of total and free cholesterol was also found to be higher in the outer zone. However, when exogenous cholesterol was added to mitochondria, there was no enhancement in side-chain cleavage activity in either zone.

Adrenal Cortex↗
PubMed1984

Enzyme histochemical studies on transplantable pancreatic adenocarcinomas in Syrian golden hamsters.

Transplantable pancreatic adenocarcinomas were established in subcutaneous tissue of Syrian golden hamsters and examined by enzyme histochemistry. The original tumors were found at week 40 after subcutaneous injection of N-nitrosobis(2-hydroxypropyl)amine (DHPN) at a dose of 250 mg/kg body weight once a week for the first 20 weeks of the experiment. They were well differentiated adenocarcinomas and their histology was not changed by serial transfer for 18 generations. Their transplantability was 67 to 100% and their average doubling time was 4.1 +/- 0.82 d. The enzymes gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), alkaline phosphatase (ALPase), and acid phosphatase (ACPase) were examined in tumor cells at the 14th and 15th generations and in ductal cells and acinar cells of normal pancreas of hamsters. Increased GGT activity was found in the tumor cells, and a strongly positive reaction was observed in acinar cells but not ductal cells of normal pancreas. LDH and SDH were found in the tumor cells, acinar cells and ductal cells. No ALPase was detected in the tumor cells, acinar cells, or ductal cells. ACPase was found in acinar cells and ductal cells, but not in the tumor cells.

Adenocarcinoma↗
PubMed1984

Differential suppression of the outer and inner zones of the adrenal cortex of the guinea pig.

To examine the regulation of the zona fasciculata and the zona reticularis of the guinea pig adrenal cortex, animals were placed on a chronic regimen of dexamethasone. Changes in adrenal zonal weight, cholesterol side-chain cleavage activity, and tissue and serum steroid concentrations were measured after 1 month of dexamethasone administration. With dexamethasone treatment, the weight of the outer zone (glomerulosa/fasciculata) decreased significantly, while the weight of the inner zone (reticularis) did not change. Cholesterol side-chain cleavage activity in mitochondria isolated from the outer zone also declined significantly, while a similar activity in the inner zone did not change. The serum cortisol concentration in response to dexamethasone administration decreased by 85%, as did the concentrations of cortisol and progesterone in the outer zone; the concentration of cortisol in the inner zone decreased by only one third, while the concentration of progesterone did not change. These results in association with previous reports indicate that the zona reticularis of the guinea pig adrenal cortex (in contrast to the zona fasciculata) is not regulated by ACTH in terms of either steroidogenesis or maintenance of cell growth.

Adrenal Cortex↗
PubMed1984

A case of calcitonin producing adenoma of the thyroid.

A thyroid tumor about 4 cm in diameter was removed from a 53-year-old female. The clinical features were those of common thyroid adenomas, such as soft, smooth-surfaced and round contour of the tumor, no calcification and no lymph node metastasis. However, microscopically, the tumor was composed of compact cell nests rather similar to paraganglioma without any follicle formation. Histochemical examination revealed its C-cell nature, such as argyrophilia and calcitonin activity, although no amyloid deposit was demonstrated. Extremely high levels of calcitonin were found in the stored serum taken pre-operatively, but serum carcinoembryonic antigen levels were within normal limits. The calcitonin level dropped to the normal range soon after the operation, indicating the absence of residual tumorous tissues. Thus, the tumor behaves as an adenoma with a C-cell nature. Interestingly enough, the benign counterpart of medullary carcinoma of the thyroid seems to be quite rare in humans, and no similar tumors have ever been reported. Variations of C-cell tumors will be discussed in relation to their production and secretion of carcinoembryonic antigen.

Adenoma↗
PubMed1984

[Surgical management of primary hyperparathyroidism].

We have experienced 186 patients with proven primary hyperparathyroidism operated on during past 16 years. In this series, 147 patients (79%) had adenoma, 24 patients (12.9%) had carcinoma and only 15 (8.1%) had hyperplasia. Because of a 92% of single gland involvement, the removal of an enlarged gland is adequate, if the remaining gland are grossly normal. Besides, interestingly enough, an incidence of parathyroid carcinoma is rather high in Japan, so that surgeons should be alert to recognize the parathyroid carcinoma on the basis of clinical and operative findings. In an effort to minimize recurrence, en bloc resection of the parathyroid carcinoma is important. When a patient with parathyroid carcinoma has a local recurrence or distant metastases, an aggressive surgical approach is recommended to alleviate hypercalcemic symptoms. The majority of patients with hyperplasia belong to multiple endocrine neoplasia, type 1. Recent development of the non-invasive diagnostic methods is remarkable. The last consecutive 31 patients underwent preoperative localization study by 201Thallium (201TI-CI) scanning and ultrasonography. 201TI-CI scanning gave the most accurate results and 100% correct localization was obtained when the parathyroid tumor was more than 1 g. However, it is noteworthy that the parathyroid tumor was less than 1 g in 64% of patients who had no evidence of generalized fibrous osteitis.

Adult↗
PubMed1984

Distribution and metabolism of N-nitrosobis(2-hydroxypropyl)amine in rats.

The metabolic fate of the lung carcinogen N-nitrosobis(2-hydroxypropyl)amine (ND2HPA) in male Wistar rats was studied. The blood level after a single intraperitoneal (i.p.) injection of [1-14C]-ND2HPA at a dose of 3 g/kg body weight reached a maximum within 1 h. Most of the administered 14C was eliminated via the urine; 90.8% of the 14C was excreted in urine within 24 h, 5.5% in faeces, and 3.2% in expired air. About 11% of the 14C was detected in bile collected over 24 h. A relatively high concentration of 14C was found in the blood and target organs, such as the lung, liver, thyroid gland and kidney 1 h after treatment. Analysis by high-pressure liquid chromatography showed that the 14C in the blood and urine was mostly accounted for by unchanged ND2HPA, together with smaller amounts of N-nitroso-(2-hydroxypropyl)(2-oxopropyl)amine (N2HP2OPA). ND2HPA and N2HP2OPA were also detected in the lung and liver of rats 30 min to 12 h after the administration and were present in higher concentrations in the blood and lung than in the liver and pancreas. Besides ND2HPA and N2HP2OPA. N-nitrosomethyl(2-hydroxypropyl)amine (NM2HPA) was also found in urine collected over 6 h. ND2HPA, N2HP2OPA and NM2HPA showed mutagenicity in the Salmonella assay system with metabolic activation by a 9000 X g supernatant of rat liver, and N2HP2OPA was also mutagenic in the presence of a rat lung preparation. These data suggest that N2HP2OPA and NM2HPA might be important intermediates in the metabolic activation of ND2HPA to its ultimate carcinogenic form in rats.

Animals↗
PubMed1983

Human medullary carcinoma of the thyroid in tissue culture.

Medullary thyroid carcinomas (MCT) were obtained from patients with Sipple's syndrome or non-hereditary MCT. Cultures of enzymatically dissociated cells showed that MCT cells were mostly free-floating cells of epithelial characters. These MCT cells preserved the ability to secrete calcitonin for a long period of in vitro maintenance. However, the MCT cells under the usual culture conditions were filled with numerous cytoplasmic granules and appeared to be extremely fragile. When MCT cells were cultured in a low-calcium medium, such granules were not observed. In addition, MCT cells in the low-calcium medium increased the amount of calcitonin in response to added calcium and tetragastrin. Therefore, the culture of MCT cells in the low-calcium medium appeared to be useful for studies about the biochemical and physiological characters of human MCT cells in vitro.

Calcitonin↗
PubMed1983

Effects of room temperature on reproduction, body and organ weights, food and water intakes, and hematology in mice.

Two consecutive generations of mice were raised at graded room temperatures ranging from 12 to 32 degrees C at intervals of 2 degrees C. The delivery rate decreased at 30 and 32 degrees C, and the litter size and weaning rate decreased above 28 degrees C. No significant difference was demonstrated within the 12-26 degrees C range for any reproduction parameters observed. The body weights of the first-generation mice born at 22 degrees C and transferred to rooms at assigned temperature did not significantly differ within the 14-28 degrees C range after 8 and 16 weeks of exposure. The second-generation mice born and reared at various temperature levels did not show significant inter-group difference in weight within the 20-26 degrees C range at any age in the growth period. No significant inter-group difference was observed within the 20-26 degrees C range in respect of food and water intakes in the second-generation mice. Hematological values and organ weights in the first and second generation mice of both sexes did not significantly differ in any parameter within the 20-26 degrees C range. The results suggest the temperature range of 20-26 degrees C to be optimal for laboratory mouse rooms.

Animals↗
PubMed1983

[Clinical experience with cefpiramide in pediatrics].

Clinical effects of cefpiramide (CPM) on 10 respiratory tract infections were excellent in 9 and poor in 1, and those on 3 urinary tract infections were excellent in 3. Although CPM is considered to be excreted mainly into bile, it was suggested that the excretion rate of CPM at doses of 10 approximately 20 mg/kg into urine is good enough. Antibacterial activity of CPM was considered to be almost the same as that of cefmetazole and cefoperazone. As to side effects, weak diarrhea was observed in 2 cases. This should be considered when CPM is given to children because of its main excretion route to bile duct.

Adolescent↗
PubMed1982

Relationship of changes in serum concentrations of prolactin and testosterone during dopaminergic modulation in males.

To evaluate the effect of PRL on the male pituitary-gonadal system, serum concentrations of PRL, testosterone, LH and FSH were determined in healthy young men daily before, during, and after 3-day oral administration of bromocriptine, metoclopramide or sulpiride. Bromocriptine (2.5 mg as a single dose) caused, concurrently with a marked suppression of serum PRL, a significant increase of serum testosterone and a transient decrease of serum LH. The changes of PRL and testosterone were negatively correlated. With metoclopramide (10 mg q.i.d.) serum PRL was increased and testosterone inversely decreased. There was no change in LH and FSH. Sulpiride (50 mg q.i.d.) evoked the elevation of serum PRL and LH, but no change in testosterone. A significant increase in serum concentration of testosterone was also observed in a patient with PRL-producing pituitary tumour and four out of seven patients with acromegaly during bromocriptine treatment. These results suggest an inhibitory effect of PRL on testosterone secretion at the gonadal level, or direct dopaminergic stimulatory control of testosterone secretion.

Acromegaly↗
PubMed1982

Regulation of allergic reaction by aerobic Corynebacterium equi extract, CEF. III. Inhibition of histamine release from rat peritoneal mast cells.

Effects of a water soluble fraction of Corynebacterium equi (CEF) on the histamine release from rat peritoneal mast cells (RPMC) were investigated. The treatment of RPMC with CEF resulted in a significant inhibition of the histamine release from RPMC which was induced by IgE antibody-antigen interaction as well as nonimmunological histamine liberators. CEF was much more effective in inhibition of IgE-mediated histamine release and compound 48/80 or polymyxin B-induced histamine release when the mast cells were treated with CEF prior to the incubation with the antigen or the liberators. In contrast, CEF was equally effective in inhibition of the histamine release by concanavalin A with phosphatidyl serine when the mast cells were treated with CEF prior to or simultaneously with the liberator. Evidence was also presented that CEF inhibits degranulation of mesenteric mast cells induced by immunological as well as nonimmunological mechanisms.

Animals↗
PubMed1982

Induction of suppressor macrophages in mice by Fusarenon-X.

Intraperitoneal injection of Fusarenon-X into BALB/c mice, a mycotoxin produced by Fusarium nivale Fn 2B, depressed polyclonal antibody formation of splenic lymphocytes in response to pokeweed mitogen (PWM). This inhibitory activity was found to reside in the surface immunoglobulin-negative spleen cell fraction of Fusarenon-X-treated mice, sIg-(FX), which comprised mainly T lymphocytes and smaller number of non-lymphocytic cellular elements. However, reconstitution experiments for in vitro antibody formation provided evidence that T lymphocytes from Fusarenon-X-treated mice, T(FX), which were separated from non-lymphocytic cells by use of carbonyl iron/magnet, were as effective as T lymphocytes from normal mice, T(N), in supporting antibody formation. Furthermore, addition of non-lymphocytic cells, NL(FX), or adherent cells, AD(FX), prepared from spleen cells of Fusarenon-X-treated mice to normal spleen cells strongly inhibited in vitro antibody formation against PWM or a bacterial lipopolysaccharide (LPS). These results strongly indicated that Fusarenon-X induced non-lymphocytic suppressor cells in the spleen of the treated mice which had features in common with activated macrophages.

Animals↗