IRISH SOCIETY OF GASTROENTEROLOGY P r o c e e d i n g s of m e e t i n g held
IMMUNE SUPPRESSION OF OBSTRUCTIVE JAUNDICE: ITS REVERSIBILITY BY INTERNAL OR EXTERNAL DRAINAGE AND THE ROLE OF T CELL SUBSETS
THE POSSIBLE ROLE OF BACTEROIDES MELANINOGENICUS EXTRACELLULAR ENZYME ACTIVITIES IN THE PATHOGENESIS OF SMALL BOWEL BACTERIAL OVERGROWTH
D. C. McCrory, I. Halliday, M. Hoper, A. Crockard*, B. J. Rowlands. Departments of Surgery and Microbiology*, The Queen's University of Belfast BT12 6BJ.
L. A. Cotter, M. Healy, M. Buckley, C. O'Morain, C. Keane, R. R. O'Moore. T.C.D. Medical School, St. James's Hospital, Dublin 8.
Patients with obstructive jaundice have a high incidence of infective complications which may in part be due to suppression of T lymphocyte function. The role of T helper (TH) and T suppressor (TS) cells in this suppression is unknown. How quickly T lymphocyte function returns after the relief of cholestasis and the efficacy of intemal as opposed to external biliary drainage in achieving this are controversial. Materials and methods. Rats were assigned to one of nine groups: controls; sham operated; bile duct ligated (BDL) for 3 weeks; BDL for 3 weeks followed by internal drainage (ID) or external drainage (ED) for 1, 2 or 3 weeks. Peripheral blood T lymphocyte function was assessed by phytohaemagglutinin (PHA) stimulation and subsequent scintillation counting. TH and TS cell numbers were measured using monoclonal antibodies and flow cytometry.
Contamination of the small bowel with an abnormal anaerobic microflora causes a variety ofintraluminal disturbances. The most important of these is lipid malabsorption which occurs in approximately 30% of patients with small intestinal bacterial overgrowth (SIBO). The pathogenesis of this malabsorption remains controversial. Bacteroidesmelaninogenicus ssp. intermedius was isolated from patients with small bowel contamination. It was shown to possess several extracellular enzyme activities: collagenase, protease, phospholipase A 2 and phospholipase C-like activity. The phospholipase activity was determined using both phosphatidycholine (PC) and phosphatidylinositol 4,5-biphosphate (PIP2) as substrates. PC is an important mediator in normal lipid absorption being involved in micellar stabilisation and removal of chylomicrons from the enterocytes. PIP 2 is an intermediate in the intracellular control of calcium release which initiates secretion in normal cells. Uncontrolled degradation of PIP2 by anaerobic bacteria may result in cellular hypersecretion. Degradation of PC and PIP 2 and the presence of protease activity in the upper small intestine of patients with SIBO by anaerobic bacteria may be a factor in the pathogenesis of lipid malabsorption in SIBO.
Results Mean ± standard error PHAb Counts/min TI-FI'S ratio n=l 1 5039+1140 2.12.x'0.20 n=l 1 4028:t: 993 ! .90"L-0.37 n=ll *1016-J: 279 1.87:t.-0.25 ID 1 wk n=8 1413+ 268 2.10&-_0.28 ID 2 wks n=8 "1893+ 718 1.69:L'0.26 ID 3 wks n=8 2167+ 515 1.89-'x0.23 ID 1 wk n=7 *1080-& 271 1.67xL0.33 ]]3 2 wks n=8 *1479-& 379 1.77!-0.12 ID 3 wks n=7 2573+1166 1.79i'0.20 TH/TS ratio: no two groups differ sigmficantly, p>O.05 ANOVA *Significant difference versus controls and shams, p