Cho, CH

Liu, ESL

Shin, VY

Ye, YN

Hong Kong Medical Journal

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Title The role of cigarette smoking and its interaction withcyclooxygenase-2 in acute ulcerative colitis in miceAuthor(s) Liu, ESL; Shin, VY; Ye, YN; Cho, CHCitationThe 8th Medical Research Conference Abstracts, Hong KongMedical Journal, Hong Kong, China, 25-26 January 2003, v. 9 n. 1Supp 1, p. 46Issued Date 2003URL http://hdl.handle.net/10722/46997Rights Creative Commons: Attribution 3.0 Hong Kong License46      HKMJ Vol 9 No 1 February 2003 SupplementThe role of cigarette smoking and its interaction with cyclooxygenase-2 in acuteulcerative colitis in miceESL Liu, VY Shin, YN Ye & CH Cho. Departments of Pharmacology, Faculty of Medicine, The University of Hong Kong,Hong Kong, China.Introduction: Epidemiological studies show that smokers are more likely to have Crohn’s disease but are lesssusceptible to ulcerative colitis. Our previous study indicated that passive cigarette smoking exacerbated the Crohn’sdisease induced by 2,4,6-trinitrobenzene sulfonic acid in rats. However, no direct evidence had been found regard-ing the protective effect of cigarette smoking on ulcerative colitis. Besides, cyclooxygenase-2 (COX-2) is stronglyassociated with inflammatory bowel disease for its inhibition could either potentiate or attenuate colitis. The aim ofthe present study is to evaluate the role of cigarette smoking on ulcerative colitis induced by dextran sulfate sodium(DSS) in mice and to determine whether COX-2 takes part in the inflammatory process in this model.Methods: Acute ulcerative colitis was induced in balb/c mice by giving 5% DSS in drinking water for 7 days. Themice were simultaneously exposed to passive 0% or 2% cigarette smoke (CS) once daily for the same period oftime. Colonic tissues were assessed for the inflammatory parameters and COX-2 expression in these animals.Results: DSS in drinking water given for 7 days increased colon weight when compared with the control. Histol-ogy findings revealed that there were infiltration of inflammatory cells and loss of glands in the colonic mucosa. Anincrease in myeloperoxidase (MPO) activity, a marker for neutrophils infiltration, was also observed. Bothimmmunohistochemistry and Western immunoblotting indicated that COX-2 was induced in the colonic tissueswith ulcerative colitis. It was accompanied with an induction of the cellular proliferation. On the other hand, pas-sive CS exposure neither affected the degree of inflammation nor the MPO activity in these animals. However, bothCOX-2 protein expression and cellular proliferation was increased in colonic tissue in mice with CS exposure aloneand synergistically induced in mice when combined with DSS.Conclusion: Passive cigarette smoking did not influence the severity of acute colonic inflammation inducedby DSS though it further provoked COX-2 expression and cellular proliferation in colitis animals. Furthermore,COX-2 was induced by CS exposure alone but did not accompany with colitis formation. All these findingsindicated that COX-2 was not directly involved in the initiation of inflammation in this acute ulcerativecolitis model. However, whether the induction of cigarette smoke on proliferation exerts beneficial effect onulcerative colitis is undefined and requires further study.Randomised controlled study of rabeprazole, levofloxacin and rifabutin tripletherapy versus quadruple therapy as second-line treatment of Helicobacter pyloriinfectionW.M. Wong, Q. Gu, S.K. Lam, F.M.Y. Fung, K.C. Lai, W.H.C. Hu, Y.K. Yee, C.K. Chan, H.H.X. Xia, M.F. Yuen, B.C.Y. WongDepartment of Medicine, University of Hong Kong, Queen Mary Hospital, Hong KongBackground and aims: To test the efficacy of rabeprazole, levofloxacin and rifabutin triple therapy versusrabeprazole-based quadruple therapy for the treatment of Helicobacter pylori (H. pylori) infection after failure ofone or more courses of H. pylori eradication therapy.Methods: One hundred and nine patients who failed previous H. pylori eradication were randomised to receive 1)rabeprazole 20mg twice daily, rifabutin 300mg and levofloxacin 500mg once daily for 7 days (RRL) or 2) rabeprazole20mg twice daily, metronidazole 400mg thrice daily, bismuth subcitrate 120mg and tetracycline 500mg four timesdaily for 7 days (quadruple). Endoscopy with biopsy for CLO test, histology and culture was performed beforetreatment. Post-treatment H. pylori status was determined by 13C-urea breath test. Metronidazole, clarithromycinand amoxycillin resistance was defined as MIC of >8 ug/ml, >2 ug/ml and >2 ug/ml respectively.Results: The clarithromycin resistance rate (79% versus 21%, P<0.001) and metronidazole resistance rate(89% versus 40%, P<0.001) was significantly higher in patients who have taken these antibiotics in theirprevious H. pylori treatment compared to those who have not. Intention-to-treat and per protocol H. pylorieradication rate were 91% / 91% for the RRL group and 91% / 92% for the quadruple group. For patientswith double resistance to metronidazole and clarithromycin, the eradication rates were 85% (17/20) in theRRL group and 87% (13/15) in the quadruple group. Compliance was greater than 95% for both regimens.Conclusion: Rabeprazole, levofloxacin and rifabutin based triple therapy and rabeprazole-based quadruple therapywere equally effective as a second-line treatment of H. pylori infection.GIH-05GIH-06

The role of cigarette smoking and its interaction with cyclooxygenase-2 in acute ulcerative colitis in mice

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The role of cigarette smoking and its interaction with cyclooxygenase-2 in acute ulcerative colitis in mice

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