The use of rhesus monkeys to study biliary secretion with an intact enterohepatic circulation

Alteration of the enterohepatic recirculation of bile acids in rats after exposure to ionizing radiation

The aim of this work was to study acute alterations of the enterohepatic recirculation (EHR) of bile acids 3 days after an 8-Gy radiation exposure in vivo in the rat by a washout technique. Using this technique in association with HPLC analysis, the EHR of the major individual bile acids was determined in control and irradiated animals. Ex vivo ileal taurocholate absorption was also studied in Ussing chambers. Major hepatic enzyme activities involved in bile acid synthesis were also measured. Measurements of bile acid intestinal content and intestinal absorption efficiency calculation from washout showed reduced intestinal absorption with significant differences from one bile acid to another: absorption of taurocholate and tauromuricholate was decreased, whereas absorption of the more hydrophobic taurochenodeoxycholate was increased, suggesting that intestinal passive diffusion was enhanced, whereas ileal active transport might be reduced. Basal hepatic secretion was increased only for taurocholate, in accordance with the marked increase of CYP8B1 activity in the liver. The results are clearly demonstrate that concomitantly with radiation-induced intestinal bile acid malabsorption, hepatic bile acid synthesis and secretion are also changed. A current working model for pathophysiological changes in enterohepatic recycling after irradiation is thus proposed.Key words: irradiation, bile acids, intestine, liver, enterohepatic recycling.

Are silicone rubber T-tubes better than latex rubber tubes in the common bile duct? A rhesus monkey model

A retrospective comparison of latex and silicone rubber T-tubes draining the common bile duct in the Rhesus monkey shows that both tubes excite an adequate local tissue reaction. However, latex rubber degenerated more rapidly than silicone rubber, the interval between insertion of the tube and onset of complications being significantly shorter (7.2 ± 0.9 (s.e.) weeks against 17.6 ± 6.2 weeks). It is suggested that silicone rubber T-tubes have a place in human biliary surgery, especially when long-term drainage of the biliary tract is required.