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Allenes are molecules based on three carbons connected by two cumulated carbon-carbon double bonds. Given their axially chiral nature and unique reactivity, substituted allenes have a variety of applications in organic chemistry as key synthetic intermediates and directly as part of biologically active compounds. Although the demands for these motivated many endeavours to make axially chiral, substituted allenes by exercising asymmetric catalysis, the catalytic asymmetric synthesis of fully substituted ones (tetrasubstituted allenes) remained largely an unsolved issue. The fundamental obstacle to solving this conundrum is the lack of a simple synthetic transformation that provides tetrasubstituted allenes in the action of catalysis. We report herein a strategy to overcome this issue by the use of a phase-transfer-catalysed asymmetric functionalization of 1-alkylallene-1,3-dicarboxylates with N-arylsulfonyl imines and benzylic and allylic bromides. [ABSTRACT FROM AUTHOR]

We report herein, a new method devised of producing neurogenic stress ulceration in rats. An experimental subarachnoid hemorrhage (SAH) was produced in rats by injecting 0.2 ml of arterial blood from other rats into the cisterna magna. Three days later, the rats were laparotomized for 1 hour under ether anesthesia, followed by restraint for 3 hours in wakefulness. The SAH rats were found to develop stress ulcers (UL-I) in the glandular stomach, which were significantly (p<0.001) more marked than those in non-SAH rats. Measurements were performed on gastric acid secretion, an important aggressive factor. It was found that the SAH rats undergoing the laparotomy-restraint stress showed a more marked increase in gastric acid secretion and a more marked reduction in MBF, than the non-SAH rats. The effects of bilateral vagotomy, upper abdominal sympathectomy and bilateral adrenalectomy were examined, and it was revealed that the SAH rats were under the condition of hyperreactivity both in the sympathetic and parasympathetic systems and, on this basis, the laparotomy-restraint stress caused the stress gastric ulceration. In this rat model, the laparotomy stress was applied under anesthesia and any exposure to low temparatures which may have interfered with blood circulation was avoided. [ABSTRACT FROM AUTHOR]

New rat model of stress ulcer, related to subarachnoid hemorrhage (SAH) was devised. A 0.2 ml of the arterial blood, obtained from another rat of the same litter, was injected into the cisterna magna and 4 days later, mild stress, consisting of restraint plus water-immersion for 3 hours to the injected rat, produced gastric ulcers. These lesions were far more marked than in usual rats undergoing the same stress (P<0.001). Using this 'SAH-stress model', effects of various counteracting measures were examined. Based on the results, we concluded that SAH produced a hypersensitivity or an abnormal exitability of the autonomic nervous centers, and the relatively mild stress effectively weakened the gastric defensive factors and strengthened the gastric aggressive factors, thus resulting in ulcer formation. [ABSTRACT FROM AUTHOR]

Experimental studies were done on rats on compensatory absorptive capacity following Martin's operation for extensive aganglionosis. Experimental aganglionosis was produced in the descending colon of rats by serosal application of 0.1% benzalkonium chloride solution. Wide side-toside anastomosis was performed between the aganglionic colon and the distal ileum, removing the remaining colon. As to absorptive capacity of water and electrolytes, this experimental intestine was compared, with other intestines, especially control intestine, in which similar side-to-side anastomosis was done between the normal colon and the normal ileum. 'Experimental' as well as control intestine showed higher absorptive capacities of water, Na and Cl per unit length than did summed up values of the ileum and the colon per unit length. Postoperative body weight curves showed fairly good increases and appearance of feces showed a fair improvement in the experimental group. Autopsy of experimental intestine revealed marked dilatation of the anastomosed ileum and mucosal hypertrophy of the anastomosed colon. These results suggested a favorable compensatory absorptive capacity following Martin's operation. [ABSTRACT FROM AUTHOR]