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J E Burkhardt

Publications and source records attributed to J E Burkhardt.

22 records · Page 2Linked to original sources
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Effects of cholestyramine and diet on small intestinal histomorphometry in rats.

Reports on the effects of cholestyramine on small intestinal structure of rats have produced contradictory data about changes in mucosal histomorphometry, perhaps due to interacting effects of dietary composition. In order to identify effects of cholestyramine and diet on structure of the small intestines, 40 male rats were divided into 4 groups of 10 and fed 1 of each of the following diets for 1 month: standard diet, purified fiber-free diet, standard diet + 2% cholestyramine, or purified fiber-free diet + 2% cholestyramine. Serum concentrations of cholesterol and triglycerides were moderately increased in rats fed the purified fiber-free diet versus the standard diet. Neither total length nor weight of small intestine were affected by either diet or cholestyramine. Mucosal weight was affected by interactions between cholestyramine and diet, indicating that outcome depended upon modulating effects of both variables. Significant interactions were similarly detected among the variables of anatomic site, diet, and cholestyramine for many histomorphometric parameters of intestinal mucosa. Cholestyramine reduced total mucosal thickness in both jejunum and ileum and reduced villus height and villus:crypt ratio in the ileum.

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Effects of nalidixic acid on hamster knee cartilage morphology and synovial fluid composition.

Quinolone-induced changes were studied in the knee joints of 4-wk-old female hamsters given intraperitoneal doses of either nalidixic acid (400 mg/kg body weight) or vehicle on days 0 and 1. After euthanasia on day 4, synovial fluid was collected for cytologic evaluation and for analysis of concentrations of hyaluronan, proteoglycans, total protein, and collagen as hydroxyproline. Slides of formalin-fixed decalcified tissues were stained with hematoxylin-eosin or safranin O for histologic scoring of lesion severity. Nine of 10 hamsters treated with nalidixic acid had fissures within articular cartilage of the femur and reduced safranin O staining of matrix indicative of loss of proteoglycans. Synovial membranes from affected joints, however, were not inflamed. Synovial fluid cell counts and cytomorphology were unaffected by treatment. In synovial fluid from 5 of 10 treated hamsters, proteoglycans were elevated by more than 2 SDs above the control group, and individual animal levels correlated with the histologic severity score (r2 = 0.36; p = 0.02). The hyaluronan content of the synovial fluid from treated hamsters was mildly but significantly elevated (p = 0.005), and the histologic severity score again correlated with individual animal levels (r2 = 0.42; p = 0.01). Hydroxyproline was unaffected by treatment. Although synovial fluid changes and histologic changes were correlated on a group basis, interanimal variability was significant and the magnitude of biochemical changes were far smaller than those that occur during inflammation. Changes in synovial fluid composition are not sufficiently robust to predict cartilage changes in individual animals.

Animals↗