Diffuse, topical application of dilute acetic acid to the serosal surface of rat colon, or standardized intraluminal (per rectum) instillation induced a reproducible, diffuse colitis in a dose-response manner. These lesions were reproduced with 100% reliability and were evaluated up to 60 days when healing occurred. Histopathological features of this chemically induced colitis were diffuse ulceration of the distal colon, occurrence of pseudopolyp-like structures, alterations in crypt depth and mucus secretion, and a transmural, nonspecific inflammatory response.
This study examined the impact of implementing a rotating dissection schedule on the attitudes and performance of first-year dental students in the gross anatomy laboratory at the University of Kentucky. In 2002-2003, half of the students assigned to each cadaver dissected the assigned objectives during the first 90 min of the laboratory session. During the last 30 min, the non-dissecting group members came into the laboratory and had the day's dissection demonstrated and explained to them via peer instruction. Dissection responsibilities rotated with each laboratory session. Eighty-eight percent of student participants were satisfied with the rotating dissection approach according to a mid-term survey, and this satisfaction level remained unchanged at the end of the semester for most students. Students' perceptions of the quality of peer laboratory presentations varied, with only 44% rating them as good or better. Eighty percent of students perceived that rotating dissection did not impede their performance, and this was confirmed by analysis of grade data. Student satisfaction and the ability to devote additional weekly curriculum time to studying anatomy in a very compressed curriculum were the main student-described benefits.
SUMMARY
A simple method of preparing ‘swiss rolls' from strips of tissue up to 500 mm in length is described. This procedure has been applied to a variety of tissues and is suitable for the preparation of both paraffin‐ and methacrylate‐embedded specimens.
Ulcerative colitis and Crohn’s disease are complex, problematic diseases of unknown etiology in man, and appropriate experimental models would be useful in elucidating their pathogenesis and treatment. Although there have been numerous attempts to produce inflammatory ulcerative colonic disease in laboratory animals resembling those human disease forms, none has been entirely successful. Investigators have conducted experiments involving almost every etiological factor suggested for initiation of these diseases. The methods reviewed in this paper include production of experimental colitis by vascular impairment, and immunological methods such as bacterial infection, allergic reactions, direct and indirect hypersensitivity reactions, as well as autoimmune mechanisms. The results of carrageenan-induced colitis, irradiation, dietary, and drug-induced techniques are also discussed and the frequency and nature of spontaneous colonic lesions in animals is summarized.
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