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D A Parks

Publications and source records attributed to D A Parks.

75 records · Page 5Linked to original sources
PubMed1982

Ischemic injury in the cat small intestine: role of superoxide radicals.

Hemorrhagic lesions in the small intestinal mucosa have been demonstrated in humans and experimental animals following hemorrhagic shock and intestinal ischemia. In order to define the role of superoxide radicals and xanthine oxidase in the pathogenesis of the mucosal lesions, we compared the microscopic mucosal changes produced by 3 h of regional hypotension (intestinal arterial pressure = 30 mmHg) in untreated cats and cats pretreated with either superoxide dismutase or allopurinol. In the untreated animals the mucosa was characterized by massive epithelial lifting down the sides of the villi, completely denuded villi, and most frequently by disintegration of the lamina propria, hemorrhage, and ulceration. Pretreatment with either superoxide dismutase or allopurinol significantly attenuated the necrosis of villus and crypt epithelium produced by 3 h of ischemia. The results of this study suggest that superoxide radicals are involved in the pathogenesis of ischemic mucosal lesions and that the enzyme xanthine oxidase is the source of superoxide radicals in the ischemic small bowel.

Allopurinol↗
PubMed1982

Comparison of partial and complete arterial occlusion models for studying intestinal ischemia.

Mucosal albumin clearance was measured in jejunal segments of dogs under control conditions and following complete or partial arterial occlusion of varying durations (1, 2, 3, or 4 hours). The rate of albumin clearance was estimated from the luminal perfusion rate and the activity of protein bound 125I in the perfusate and plasma. Partial and total arterial occlusions of 60 minutes to 4 hours' duration produced significant increases in mucosal albumin clearance. The magnitude of the rise in albumin clearance was directly related to the duration of ischemia in both total and partial arterial occlusion models. However, the magnitude of the increase in albumin clearance was significantly greater with total arterial occlusion for any given duration of ischemia. The albumin clearance results obtained in the present study compare favorably with previously reported morphologic changes in the intestinal mucosa produced by both total and partial occlusion of the superior mesenteric artery. The agreement between morphologic and physiologic measurements indicates that mucosal albumin clearance may be a useful tool for studying the pathophysiology of intestinal ischemia.

Animals↗