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Biomedical subjects

S Shima

Publications and source records attributed to S Shima.

At least 145 records · Page 8Linked to original sources

beta-Adrenergic stimulation of the adenosine 3',5'-monophosphate system regulated by cholinergic stimuli in the prostate.

Acetylcholine significantly inhibited isoproterenol-stimulated adenosine 3',5'-monophosphate (cAMP) levels of rat prostatic tissue in a concentration-dependent fashion. Atropine but no hexamethonium reversed the inhibitory action of acetylcholine. Tetracaine and verapamil abolished the inhibitory effect of acetylcholine on isoproterenol-stimulated accumulation of cAMP. Exclusion of calcium also eliminated the effect of acetylcholine. Inhibitory regulation of cAMP levels was reproduced by the divalent cation ionophore A23187. These observations suggest that beta-adrenergic stimulation of the cAMP system of the prostate is regulated by cholinergic stimulation involving a specific muscarinic receptor with calcium-dependent mechanism sensitive to verapamil or tetracaine.

1-Methyl-3-isobutylxanthine↗

[Studies on the effects of beryllium oxide in purity and fired temperature to the occurrence of chronic pulmonary berylliosis].

Among various beryllium (Be) compounds, beryllium oxide (BeO) has so far been noted as a causative substance which introduce chronic pulmonary berylliosis. In our study, chronic pulmonary berylliosis was experimentally evoked by using two species of BeO with individual purity and fired temperature (A group: 95.0% in purity, and 1,300 degrees C or above in fired temperature, B group: 99.9% in purity, and 800-1,000 degrees C in fired temperature), and demarcation of prepared Be concentration involving in the genesis of the disorder was examined. BeO with various concentrations ranging from 200 micrograms to 0.1 micrograms were mixed with 0.1% agar solution and infused into right thorax cavity of male guinea pig, following which variation of the body weight was checked and pulmonary histo-pathological findings, peripheral hematological tests, and sero-biochemical tests were carried out on a periodical basis at 8 weeks, 16 weeks, and 32 weeks. The results obtained are outlined herein. 1) Body weights of test animals in both A group and B group were significantly decreased as compared with that of the control. 2) Pulmonary histo-pathological findings revealed the genesis of epitheloid-cell granuloma in the lungs where non-infusion sides were included, which resembled to non-caseating granuloma in the human pulmonary berylliosis. 3) The frequency in the genesis of epithelaid-cell granuloma was 1/36 (2.8%) in A group and 4/35 (11.4%) in B group, granuloma formation being marked in the latter. 4) Examination of the frequency in terms of BeO dosages revealed no results suggesting the dose-response relationship between pulmonary granuloma formation and the dosage. 5) There were no changes worthy of note in peripheral hematological tests. 6) Sero-biochemical tests revealed that alkaline phosphatase value together with total protein in each was significantly decreased in B group at 32 weeks following the infusion.

Berylliosis↗

Effect of adrenergic stimulation on adenylate cyclase activity in rat prostate.

Adrenergic stimulation of the cyclic AMP system of the prostate gland of the rat has been investigated. The observed order of potency for adrenergic agonists in stimulating prostatic adenylate cyclase activity was isoproterenol greater than epinephrine approximately or equal to salbutamol greater than norepinephrine, indicating properties characteristic of beta-2-adrenergic receptor-sensitive adenylate cyclase systems. Dopamine stimulation of the enzyme was exclusively inhibited by a dopamine antagonist, haloperidol, suggesting the presence of dopamine-sensitive receptor in the prostate gland. An initial incubation of the gland with isoproterenol or dopamine resulted in a decrease in maximal enzyme activation by catecholamine, either isoproterenol or dopamine, with no change in hormone affinity. The findings that refractoriness of beta-adrenergic and dopaminergic receptor-adenylate cyclase systems was induced by both receptor-agonists suggest an interaction of an agonist-induced desensitization with another receptor or receptor-enzyme complex in the prostate gland.

Adenylyl Cyclases↗

Regulation of the adenylate cyclase system by catecholamines in the rat prostate.

Tolerance to catecholamines in the beta-adrenergic and dopaminergic receptor-adenylate cyclase system from the rat prostatic membrane has been studied. Preincubation of the tissue with isoproterenol produced not only a decrease in beta-adrenergic receptors and its sensitive adenylate cyclase activity, but also a reduction in dopaminergic response. Similarly, exposure to dopamine resulted in a decline both of isoproterenol- and dopamine-stimulated adenylate cyclase activity. A beta adrenergic antagonist, propranolol, exclusively blocked desensitization in the beta-adrenergic and dopaminergic adenylate cyclase system caused by isoproterenol, while dopamine-induced refractoriness was prevented by a dopaminergic antagonist, haloperidol. These results suggest that desensitization of the beta-adrenergic and dopaminergic adenylate cyclase system begins on receptor-occupation by its specific agonist.

Adenylyl Cyclases↗

Carcinoma within a middle esophageal (parabronchial) diverticulum: a case report and the review of the literature.

A case of carcinoma developed in the middle esophageal (parabronchial) diverticulum is reported. In recent literature, 44 cases of carcinoma in esophageal diverticulum were reported. Most of the patients who had carcinoma in a diverticulum have a long-term history of symptom related to diverticula. Prognosis of these patients was poor because the carcinomas were far advanced when they were found. Therefore, the patient with esophageal diverticulum should be checked with esophagogram, esophagoscopy and biopsy, considering the possibility of development of carcinoma. Most of the cases of carcinoma in a diverticulum were treated with diverticulectomy. However, we consider that radical esophagectomy is a better method of treatment.

Aged↗

Studies on cyclic nucleotides in the adrenal gland. X. Effects of adrenocorticotropin and prostaglandin on adenylate cyclase activity in the adrenal cortex.

Effects of ACTH and prostaglandin E1 (PGE1) on adenylate cyclase activities in the zona glomerulosa (the capsular fraction) and the zona fasciculata-reticularis (the decapsulated fraction) from rat adrenocortical glands have been studied. Stimulation by ACTH of adenylate cyclase activity was observed in both the capsular and decapsulated fractions in a similar dose-dependent manner. PGE1 only stimulated adenylate cyclase activity in the capsular fraction. The maximal stimulations induced by ACTH and PGE1 were additive on the capsular enzyme. A prostaglandin antagonist, polyphloretin phosphate failed to inhibit ACTH stimulation of adenylate cyclase at a concentration which completely blocked the effect of PGE1. [3H]PGE1 bound to subcellular fractions of both the capsular and decapsulated fractions of the gland. These results suggest that the capsular fraction possesses receptors for PGE1 coupled to the adenylate cyclase system which are distinct from those for ACTH. On the other hand, PGE1 receptors in the decapsulated fraction seem not to be coupled to the adenylate cyclase system.

Adenylyl Cyclases↗