Yoshinari Hashimoto

Inhibitory Effect of Peptide YY on Gastric Acid Output in Rats

The administration of peptide YY (PYY: 0.8, 1.6 and 3.2 nmol/kg/h, i.v.) to fasting rats inhibited not only baclofen (2 mg/kg, s.c.)-stimulated gastric acid output and gastric mucosal blood flow, but also pentagastrin (8 micrograms/kg/h, i.v.)-stimulated gastric acid output. PYY (3.2 nmol/kg/h) reduced baclofen-induced acid output more than pentagastrin-induced acid output, i.e., by 61.8 +/- 11.5% compared to 35.3 +/- 8.2%. PYY inhibited acetylcholine (ACh) release from cholinergic nerve endings of gastric body evoked by electrical transmural stimulation (ETS: 1 msec, 10 V, 3 Hz, 30 sec) by 47.2 +/- 3.5%. The mechanism of the inhibitory effect of PYY on gastric acid output seems to involve decreased gastric mucosal blood flow and reduced ACh release from cholinergic nerves.

The mechanism of acute gastric ulcer after induced hemorrhagic shock.

Changes in gastric mucosal blood flow were investigated for their relationship to gastric mucosal prostaglandin E2 (PGE2) and noradrenaline (NA) in rats with hemorrhagic shock. The results were as follows: 1) Gastric mucosal blood flow and NA decreased after hemorrhage. Gastric mucosal PGE2 initially increased after exsanguination and then markedly decreased. 2) Administration of NA before hemorrhage resulted in an increase of PGE2. However, the PGE2 value for animals receiving NA after hemorrhage was not different from that of non-NA-treated group. 3) Pre-treatment with PGE2 suppressed the reduction in both gastric mucosal blood flow and NA and the development of ulcer. These results suggest that the increase in gastric mucosal PGE2 in the early stage of shock might represent a phenomenon of adaptation by the adrenergic activation, and the decrease in PGE2 in the late stage might result from impaired synthesis of PGE2 due to persistent hypoxia and might be one of the possible factors in ulcer formation.

Experimental Study of Vagotomy for Prevention of Stress Ulcer after Hepatectomy of Cirrhotic Livers Its Influence on Hepatic Regeneration

We experimentally studied the influence of vagotomy on hepatic regeneration in rats after hepatectomy of cirrhotic livers. In animals that underwent hepatectomy plus vagotomy the reduction in gastric pH was suppressed, but gastric mucosal blood flow was less than that in control animals that received hepatectomy alone. The suppression of 3H-thymidine uptake percentage and thymidine kinase activity after hepatectomy was more marked in animals treated with hepatectomy plus vagotomy than in controls treated with hepatectomy alone. Hepatic DNA level tended to be lower in animals treated with hepatectomy plus vagotomy than in controls. In animals treated with hepatectomy plus vagotomy, the peak level of the mitotic index was lower and the hepatic regeneration rate was evidently suppressed. These results suggest that it is not appropriate to apply vagotomy, during hepatectomy of cirrhotic livers, for the prevention of postoperative stress ulcer because it causes a marked reduction in gastric mucosal blood flow and suppresses hepatic regeneration.

Modification of endoscopic mucosal resection to collect plural polypectomied specimens with clip connected with string using a one-channel colonoscope

Background:  Multiple colon polyps and early cancers are often detected at colonoscopy, but we could not collect all polypectomied specimens in one insertion of a colonoscope. Endoscopic mucosal resection (EMR) may often be very difficult for the collection of the size, type, form, or location of the polyps.

A Rare Case of Bile Duct Cancer Associated with Pancreaticobiliary Maljunction without Bile Duct Dilatation Diagnosed by MRCP.

膵・胆管合流異常の診断にMRCPが有用であった胆管非拡張型合流異常に合併した胆管癌の1例を経験したので報告する. 症例は70歳の女性. 一過性の右季肋部痛あり, その6か月後黄疸が出現した. 全身状態は暦年齢以上に不良であった. MRCPでは中部胆管に縦径2cmの腫瘍像, 胆管の完全閉塞がみられたが, 腫瘍より下流の胆管に拡張はなく, 共通管が1.5cmの胆管合流型の膵・胆管合流異常を認めた. 高齢で低栄養であるため, 胆管切除術を施行した. 手術診断はEM1, DM0, HM0, Surgical Stage I, Cur Bであったが, 病理組織学的所見は高分化型管状腺癌, hm2, em2, comprehensive stage II, cur Cであり癌の遺残を認めた. 本例は非拡張型合流異常における積極的分流手術の必要性を示唆する1例と考えられた.