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103 results on '"Shirai, Yasumasa"'

11. Acetylcholine increases intracellular [Ca.sup.2+] in the rat pituitary folliculostellate cells in primary culture

Author

NAKAJIMA, YUSAKU, UCHIYAMA, MAKI, SHIRAI, YASUMASA, SAKUMA, YASUO, and KATO, MASAKATSU

Subjects
Atropine -- Physiological aspects, Acetylcholine -- Physiological aspects, Pituitary hormones -- Physiological aspects, Biological sciences
Abstract

Nakajima, Yusaku, Maki Uchiyama, Yasumasa Shirai, Yasuo Sakuma, and Masakatsu Kato. Acetylcholine increases intracellular [Ca.sup.2+] in the rat pituitary folliculostellate cells in primary culture. Am J Physiol Endocrinol Metab 280: E608-E615, 2001.--Pituitary folliculostellate cells (FSCs) are thought to partially inhibit pituitary hormone secretion through a paracrine mechanism. In this process, one of the important questions is what factors regulate the function of FSCs. Because ACh is synthesized in and possibly released from the corticotrophs and lactotrophs, we examined whether FSCs respond to ACh by the method of [Ca.sup.2+] imaging in primary cultured FSCs from male Wistar rats. ACh (30 nM-3 [micro]M) increased intracellular calcium concentration ([[[Ca.sup.2+]].sub.i]) of FSCs in a concentration-dependent manner, with an initial rapid rise followed by a relatively sustained increase. The complete block of the response by atropine and pirenzepine suggests involvement of muscarinic receptors. Depletion of the stored [Ca.sup.2+] by thapsigargin blocked the response completely. Blockers of phospholipase C, U-73122 and neomycin, suppressed significantly the rise of [[[Ca.sup.2+]].sub.i]. These results suggest that ACh increases [[[Ca.sup.2+]].sub.i] in FSCs by activating phospholipase C, presumably through activation of [M.sub.1] receptors. The rise in [[[Ca.sup.2+]].sub.i] could trigger a variety of [Ca.sup.2+]-dependent cellular processes, including the synthesis and release of bioactive substances, which in turn act on endocrine cells. cholinergic modulation; paracrine mechanism; calcium imaging; [M.sub.1] receptor

Published
2001

12. Clinical outcomes of lumbar disc herniation treated with microdiscectomy

Author

Ito Hiromoto, Miyamoto Masabumi, Hashiguchi Hiroshi, Nakayama Yoshihito, and Shirai Yasumasa

Subjects
medicine.medical_specialty, Disc herniation, Scoring system, business.industry, Low back pain, Surgery, Lumbar, Blood loss, Improvement rate, Medicine, Postoperative outcome, Lumbar disc herniation, medicine.symptom, business
Abstract

Microdiscectomy was performed on 75 patients (54 males and 21 females with an average age of 35.0 years at operations) diagnosed with lumbar disc herniation. The disc herniations were located as follows: L1-2; 1, L2-3; 2, L3-4; 9, L4-5; 46, and L5-S1; 17. All patients exhibited herniation at a single level. The average follow-up period was 64.4 months. The postoperative outcomes were evaluated according to the Japanese Orthopaedic Association scoring system for lumbar disease and Hirabayashi’s improvement rate. Postoperatively, the average JOA score improved from 12.1 to 26.7 points. Hirabayashi’s improvement rate was 86.4%. A recurrence of same level disc herniation was observed in 3 patients. We conclude that microdiscectomy provided satisfactory postoperative outcome in majority cases. Average intraoperative blood loss was 36.5g. Postoperatively, only 6.7% complained of low back pain, suggesting that this procedure was less invasive. Microdiscectomy has some problems such as a postoperative treatment program and possible recurrence of herniation. However, since microdiscectomy is less invasive and obtains satisfactory postoperative outcomes, it is still considered to be an effective procedure.

Published
2002

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