Distribution of Mosquitoes on a Hill of Nagasaki City, with Emphasis to the Distance from Human Dwellings

Mosquito larvae were examined by using an ovitrap and adults by human bait catch from May to August in 1989 at 27 sites from the foot to the top of Konpira Hill of Nagasaki City, ranging from 120 to 320m in altitude. Dominant mosquito species of both larvae and adults were Aedes japonicus, Ae. albopictus and Tripteroides bambusa, but remarkable differences were recognized in distribution among species. Ae. albopictus was abundant near the foot of the hill where human dwellings were located, while Ae. japonicus was rather evenly distributed from the foot to the top and Tr. bambusa was abundant near the top. More abundant Ae. albopictus near the foothill is probably due to a marked feeding preference for man

Experimental-Induced Colitis in Rats by Ethanolic Solution of Trinitrobenzene Sulfonic Acid and Ethanol Alone : A Comparative Study

Epidemiological data suggest an increase in both developed and undeveloped countries of inflammatory bowel disease. Furthermore, its etiology and pathophysiology remain unknown. Appropriated animal models are needed. We have studied a rat model of hapten-induced chronic colitis. In Wistar rats, intracolonic instillation of 20 mg or 42 mg of the hapten trinitrobenzene sulfonic acid in 30 % and 40 % ethanol proved to induce chronic colitis after 14 to 21 days of administration, in dose-dependent fashion when compared with ethanol alone that induced only acute colitis after three days of administration. This chronic colitis shares some characteristics with inflammatory bowel disease in humans, specially with Crohn\u27s disease, such as transmural inflammation, development of strictures, ulcerations and infiltration of inflammatory cells throughout the colonic wall. These features make this model suitable for further studies of intestinal inflammation

Significance of Impairment of Antioxidants in Colonic Epithelial Cells Isolated From TNBS-Iuduced Colitis Rats

The functional status of glutathione (GSH), its related enzymes and Cu, Zn-superoxide dismutase (SOD) in colonocytes isolated from trinitrobenzene sulphonic (TNBS)-induced colitis rats was studied. Colitis (T group) was induced in Wistar rats with 42 mg TNBS dissolved in 0.35 ml of 40% (v/v) ethanol instilled into the colon. The animals were sacrificed on day 14 and compared with saline-instilled rats (S group). The GSH concentration and the enzymatic activities of glutathione peroxidase (GPx), glutathione S-transferase (GST), and SOD were spectrophotometrically estimated. The severity of colitis was assessed histologically and by myeloperoxidase activity (MPO) in whole colonic tissue. The body weight loss of the rats in the T group was marked. In colonocytes isolated from rats in the T group, the concentration of GSH (7.9 ±1.4 vs.11.3 ± 0.4 nmol/mg protein, p < 0.05) and the activities of GST (104.4 ± 10.3 vs. 146.2 ± 18.5 mU/mg protein, p < 0.05) and SOD (74.4 ± 8.9 vs. 99.8 ± 7.5U/mg protein, p < 0.05) were lower, but the activity of GPx (430.0 -±14.1 vs. 283.9 ± 10.0 mU/mg protein, p < 0.05) was higher than in the S group. As expected, the activity of MPO in the T group was higher than in the S group (371.2 ± 14.7 vs. 158.9 ± 8.4 mU/mg tissue, p<0.05) and histologically, colitis was only observed in rats in the T group. In conclusion, the functional status of antioxidants in the colonic epithelial cells of rats challenged with TNBS solution is impaired. This impariment may make them more susceptible to oxidative damage that may contribute to the development of the lesions observed in this model. Further studies at the molecular level are necessary to investigate these novel findings in this model and their potential application for testing new therapeutic approaches in inflammatory diseases of the intestinal tract