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Biomedical subjects

S Oishi

Publications and source records attributed to S Oishi.

At least 91 records · Page 5Linked to original sources
PubMed1988

A sensitive radioimmunoassay of alpha human atrial natriuretic polypeptide using monoclonal antibody recognizing human form ring structure.

A monoclonal antibody (C351) against alpha human atrial natriuretic polypeptide (alpha hANP) recognizing human form ring structure was established and applied to a radioimmunoassay of plasma alpha hANP. The minimum detectable amount in terms of 10% radioligand displacement relative to zero dose were 0.28 fmol/tube, corresponding to 0.7 fmol/ml in plasma after extraction using Sep-Pak C18 cartridges. When the mean plasma levels at recumbent position in fasted morning were compared in 10 young (less than 30 years) and 10 elderly (greater than or equal to 50 years) healthy subjects taking normal sodium diet, it was slightly higher in the latter (3.2 +/- 0.4 vs 4.7 +/- 0.5 fmol/ml, mean +/- SE, p less than 0.05). After i.v. infusion of hypertonic saline (2.5% NaCl) at a rate of 0.24 ml/kg/min for 20 min in 6 normal subjects (26 to 35 years), it was increased from 4.1 +/- 0.4 to 5.9 +/- 0.7 fmol/ml (p less than 0.01). In 6 patients with essential hypertension (34 to 57 years), it was elevated with high salt intake, i.e. 3.3 +/- 0.3, 3.9 +/- 1.03 and 7.6 +/- 1.5 fmol/ml under 34, 170 and 340 mEq NaCl/day for 7 days, respectively. From these results, the radioimmunoassay of plasma IR-alpha hANP using MAb C351 seems to be quite suitable to detect rather small changes at low plasma concentrations and to investigate a physiological importance of alpha hANP in man.

Adult↗
PubMed1988

Toxins contained in Microcystis species of cyanobacteria (blue-green algae).

Cyclic peptide toxins were analyzed for three Microcystis species (M. aeruginosa, M. viridis and M. wesenbergii) using an ODS-silica gel cartridge and high performance liquid chromatography with ODS-silica gel. On strain of M. aeruginosa contained a high amount of microcystin (cyanoginosin) YR and a lesser amount of LR. Three toxins, microcystin-RR, -YR and -LR, were detected in two strains of M. aeruginosa and four of M. viridis. The main component of the toxins of these strains was microcystin-RR. M. wesenbergii showed no peak in the area where the three toxins were obtained in other Microcytisis species by HPLC analysis. LD50 values of the purified toxins of YR and LR were similar, while a lower toxicity was estimated for RR. This explains the relatively weak toxicity of M. viridis whose main component is microcystin-RR.

Animals↗
PubMed1988

Urinary normetanephrine and metanephrine measured by radioimmunoassay for the diagnosis of pheochromocytoma: utility of 24-hour and random 1-hour urine determinations.

To validate the clinical usefulness of recently developed normetanephrine (NM) and metanephrine (M) RIA for the diagnosis of pheochromocytoma, urinary excretion of catecholamines and these metabolites were determined in 30 normal subjects, 40 patients with essential hypertension, 30 patients who were suspected to have but ultimately proven not to have a pheochromocytoma (pheochromocytoma-suspect), and 31 patients with a surgically verified pheochromocytoma. Abnormally high catecholamine excretion (epinephrine plus norepinephrine) was found in patients with pheochromocytoma compared with that in the normal subjects and the essential hypertension group. However, 3 of 31 patients with pheochromocytoma had urinary catecholamine excretion that overlapped the values in the pheochromocytoma-suspect group. Both urinary NM and M excretion also were elevated in patients with pheochromocytoma, but in 4 of 31 patients with pheochromocytoma urinary M excretion was within the range found in 1 or more of the other groups. Total M (NM plus M) excretion of more than 5485 nmol/day (as NM) was found in all patients with pheochromocytoma, and all patients had values that were higher than the highest values in the normal subjects or the patients with no evidence of pheochromocytoma. To save time and simplify the diagnostic work-up of patients suspected of having a pheochromocytoma, we also determined the NM and M concentrations in randomly voided 1-h urine samples in 24 patients with pheochromocytomas, 31 patients with essential hypertension, and 16 normal subjects. Abnormally high total M excretion was found in all patients with pheochromocytomas, and there was no overlap with the values in the patients with essential hypertension or the normal subjects. We conclude that total M measurements in both 24-h and random 1-h urine samples are useful in diagnosing pheochromocytomas.

Adolescent↗
PubMed1988

Periodic fluctuation of blood pressure and its management in a patient with pheochromocytoma. Case report and review of the literature.

The case of a 69 year old man with a right adrenal pheochromocytoma who manifested cyclic fluctuations of blood pressure with a cycle length of 9 to 13 min is reported. We collected and reviewed 14 similar cases previously reported in the literature. In these cases, right adrenal pheochromocytoma was most common, while 1 case involved the left adrenal and 2 cases were of extra-adrenal origin. The incidence in males was twice that in females and the median age was 45.3 years. Although a good correlation between the blood pressure and plasma norepinephrine concentrations was observed in our patient, the exact mechanism for the cyclic fluctuations of blood pressure is not known. In our patient, both YM-09538 and bunazosin were effective in controlling severe hypertension preoperatively. YM-09538 induced significant increases in urinary norepinephrine concentrations (1327 +/- 238 micrograms/day), while bunazosin induced a significant decrement in urinary norepinephrine concentrations (475 +/- 188 micrograms/day) compared with pretreatment levels (900 +/- 42 micrograms/day) (p less than 0.01). These observations indicated that bunazosin as a postsynaptic alpha-adrenergic receptor blocker interfered with release of norepinephrine from the tumor and thus might be beneficial in the management of elevated blood pressure in patients with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1986

Testicular atrophy induced by di(2-ethylhexyl)phthalate: changes in histology, cell specific enzyme activities and zinc concentrations in rat testis.

Daily administration of 2g/kg/day di(2-ethylhexyl)phthalate (DEHP) to immature rats was found to cause testicular atrophy and reduce zinc concentration. Specific activities of testicular enzymes associated with postmeiotic spermatogenic cells, such as lactate dehydrogenase isozyme-X, hyaluronidase and sorbitol dehydrogenase, were lower than those of control by day 10, coincident with degeneration of spermatogenic cells. The specific activities of enzymes associated with premeiotic spermatogenic cells, Sertoli cells or interstitial cells (beta-glucuronidase, gamma-glutamyl transpeptidase and malate dehydrogenase) were higher than those of control by day 10. The specific activities of alcohol dehydrogenase and aldolase, zinc containing enzymes, increased after DEHP treatment in spite of the decrease in zinc concentration in the testis. In conclusion, changes in several testicular cell-specific enzymes appear to be useful biochemical markers of testicular injury induced by testicular toxicants such as DEHP. However, these changes occurred after or simultaneous with massive histological or morphological changes rather than prior to such changes.

Alcohol Oxidoreductases↗
PubMed1986

Acute toxicity of Microcystis aeruginosa and its cardiovascular effects.

The acute toxicity of a water extract from unialgal-cultured blue-green alga Microcystis aeruginosa M228 on mice and rats was studied. The mice intraperitoneally injected with the extract became lethargic and piloerection was seen. Terminally their ears, tails, limbs, and eyes became chalky white. The LD50 value of the extract for mice was estimated at 14.4 mg dry wt of cells/kg and that of rats was 67.4 mg/kg. Tachycardia was shown in the mice injected with the extract. A value of LD50 of coadministration of the extract and phenoxybenzamine in mice was significantly larger than that of the extract alone and survival time of mice injected with the extract and phenoxybenzamine was prolonged. These results suggest that the extract of the alga may take the acute toxic effects via the sympathetic nervous system.

Animals↗
PubMed1986

Imaging and uptake mechanism of 131I-meta-iodobenzylguanidine in medullary thyroid carcinoma.

131I-meta-iodobenzylguanidine (131I-MIBG) was also taken up by medullary thyroid carcinoma (MTC) as well as by pheochromocytoma in two patients with Sipple's syndrome. However, the mechanism of 131I-MIBG uptake by MTC has not been clarified yet. We measured tissue catecholamine levels in three MTC, since MTC can produce several active substances. Catecholamines were detected in various amounts in all MTC, but not in normal thyroid tissues. These findings suggest that MTC can produce catecholamines and therefore, 131I-MIBG is taken up and stored in catecholamine vesicles of MTC, like pheochromocytoma and neuroblastoma. We conclude that 131I-MIBG may be applied not only to diagnosis but also for the treatment of patients with MTC.

3-Iodobenzylguanidine↗
PubMed1986

Pheochromocytoma associated with adrenocortical adenoma: case report and literature review.

The case of a 60-year-old woman with pheochromocytoma and concomitant adrenocortical adenoma in the same gland is presented. She complained of episodic headache, palpitation, nausea, vomiting and sweating. Physical examination revealed that the patient has generalized obesity, wet skin and paroxysmal hypertension, but no signs of Cushing's syndrome. Elevated levels of urinary noradrenaline, adrenaline and total metanephrine were sequentially observed. In addition, urinary 17-OHCS was also slightly elevated, but plasma cortisol was normal and suppressed after oral administration of 0.5 mg of dexamethasone. Abdominal echography and CT scanning demonstrated a left adrenal tumor, which took up both 131I-meta-iodobenzylguanidine and 75Se-scintadoren in the same region. A left adrenalectomy was performed and the tumor was found to consist of two parts, pheochromocytoma (2.5 X 2.5 X 2.5 cm) and cortical adenoma (2.5 X 3 X 5 cm). A total of 23 reported cases showing evidence of hyperfunction of the adrenal cortex and the medulla were noted. So far as we know, this patient was the second case of pheochromocytoma with adrenocortical adenoma in Japan.

Adenoma↗
PubMed1986

[The suppressive effect of pyrrole-2-carboxylic acid on platelet aggregation].

In the course of a search for novel antibiotics, an antiplatelet substance was isolated from the fermentation broth of Streptomyces sp. No. 82-85. Thereafter, the active substance was identified as pyrrole-2-carboxylic acid (P2C) by structural studies. The effects of P2C on adenosine diphosphate (ADP)-, arachidonic acid-, collagen- or tumor cell-induced platelet aggregation were examined in vitro and ex vivo. In in vitro studies, P2C (25-100 micrograms/ml) suppressed the aggregation of platelets of normal Wistar rats. The intraperitoneal administration of P2C (200 mg/kg) to rats and rabbits suppressed platelet aggregation induced by ADP, arachidonic acid and collagen when examined for 0.5-3 hours after administration. The agent also suppressed platelet aggregation induced by both mouse syngenic tumors, Meth-A fibrosarcoma and IMC carcinoma in vitro.

Adenosine Diphosphate↗
PubMed1985

Reversibility of testicular atrophy induced by Di(2-ethylhexyl) phthalate in rats.

Previous studies have shown that di(2-ethylhexyl) phthalate (DEHP) results in atrophy of testes and accessory sex organs accompanied by a decreased testicular concentration of zinc in rats. An experiment was performed to determine whether those changes in rat testes are reversible changes. Young Wistar male rats were administered 2.0 g/kg of DEHP for 14 days. At that time, one-half of the rats were killed for determination of zinc and testosterone concentrations in the testis, liver, and serum, and organ weights. The remaining rats were maintained for additional 45 days without further DEHP administration. Testicular weight of rats administered DEHP over the 14-day period was significantly less than that of the control animals, and testicular testosterone content and zinc concentrations were less than those of the control animals. At the end of the 45-day recovery phase, serum testosterone concentration returned to the control level, but testicular zinc concentration and testosterone content were still lower than those of the control animals. In addition, testicular weight of DEHP-treated rats was lower than that of the control animals and histologically, only a small number of seminiferous tubules showed spermatogenesis. These results indicate that, morphologically, DEHP-induced testicular atrophy appears to be of limited reversibility.

Animals↗
PubMed1984

A search for the ideal society. The assimilation of immigrants into American life.

The influx of around thirty million European immigrants into the United States in the relatively short time of a little more than a hundred years (1815-1920's) created a great challenge for the American people in their efforts to build a strong society. The newly arrived immigrants had the challenge of assimilating into a new culture and the native Americans found the supremacy of the Anglo-Saxon culture, upon which they hoped to build the ideal society, challenged by the various cultures of the immigrants. To see how both the native Americans and the immigrants faced this problem, three theories, the total assimilation theory, the melting pot theory, and the multi-cultural theory or cultural pluralism are investigated. My own reasons for thinking that the American society has not and will not become a melting pot and what I think is the best way for a heterogeneous society to strive to become an ideal society are presented in the conclusion.

Cultural Characteristics↗