Bile drainage

There is considerable enterohepatic circulation of folate, equivcdent to about one-third of the dietary inttike. Methyl-tetrahydrofolate is secreted in the bile, then reabsorbed in the jejunum together with food folates. In experimented animeds, bile drainage for 6 hours results in a reduction of serum folate to 30% to 40% of normal (Steinberg et ed., 1979). There is very little loss of folate jejunal absorption is very efficient, emd the fecal excretion of 450 nmol (200 of folates per day largely represents synthesis by intestinal flora and does not reflect inttike to any significant extent. 

Excretion of methylmercury may also be enhanced by bile drainage either through catheterization and drainage of the choledochal duct or by surgical establishment of gallbladder drainage (Berlin 1986). However, this method has not been used therapeutically. 

The most common situations in which bile salts are deficient in the small intestine are (1) T-tube drainage of the common bile duct and (2) partial or complete interruption of ileal absorption, as in regional enteritis or ileal resection or bypass. In the former group, bile drainage is usually incomplete and temporary, so that most patients tolerate this period well without... 

The biliary system consists of the liver, the gall bladder and its associated drainage ducts which combine with the pancreatic duct to form the common bile duct. Situated in the upper right quadrant of the abdomen this is a highly vascular organ being perfused by... 

There are occasional anomalies to the rule that food reduces and delays peak plasma concentration. The anti-fungal drug, griseofulvin, has enhanced absorption if taken with a meal - possibly because it becomes emulsified by bile salts and passes more readily into the lymphatic drainage of the gut which bypasses the liver, entering the venous system directly. The immuno-suppressant cyclosporin, and calcium salts in general, show a similar increase in absorption when taken with a fatty meal. 

Fig. 1. Representative time-course of bile flow in anesthetized rats with separate drainage of die bile. Values are mean +=— SEM, n = 4.

The peripheral effects concern the motility and tonus of gastrointestinal smooth muscle segmentation is enhanced but propulsive peristalsis is inhibited. The tonus of sphincter muscles is markedly raised (spastic constipation). The antidiarrhetic effect is used therapeutically (loperamide, p.180). Gastric emptying is delayed (pyloric spasm) and drainage of bile and pancreatic juice is impeded because the sphincter of Oddi contracts. Likewise, bladder function is affected specifically bladder emptying is impaired owing to an increased tone of the vesicular sphincter. 

Conjugated (partly combined) hyperbilirubinaemias with unpaired drainage of bile acids... 

Drainage therapy results in subjective improvement and decreases the risk of cholangitis. Techniques used include biliodigestive anastomosis, percutaneous trans-hepatic drainage or an endoprosthesis to bridge bile-duct stenosis. 

Hepatic bile acid synthesis amounts to about 0.8-1 g/day. When loss of bile occurs owing to drainage... 

Since very little bile acids are transported via the lymph [224], the increased cholesterol 7a-hydroxylase activity observed after lymphatic drainage [225] is not due to depletion of bile acids. In view of the fact that the synthesis of cholesterol increases after lymphatic drainage, it is possible that the increased 7a-hydroxylation in this case may be due to increased supply of newly synthesized cholesterol. 

The microsomal 12a-hydroxylase seems to be influenced by the flux of bile acids through the liver in a similar way as cholesterol 7a-hydroxylase. Biliary drainage in rats leads to a 2-fold stimulation of 12a-hydroxylase [44] perhaps due to reduced intake of food [252]. However, it was shown later that 12a-hydroxylation of 7a-hydroxy-4-cholesten-3-one was inhibited by feeding rats different taurine-conjugated bile acids at the 1% level [110]. Ahlberg et al. showed that the microsomal 12a-hydroxylase in human liver was inhibited by about 50% after treatment for 8 weeks with chenodeoxycholic acid, 15 mg/kg body weight [HI]. The increased ratio between cholic acid and chenodeoxycholic acid observed after treatment with cholestyramine is also consistent with an inhibitory effect of reabsorbed bile acids on the 12a-hydroxylase [219]. 

The need for biliary drainage in children is less frequent than in adults however, there are a number of indications for performing a percutaneous tran-shepatic cholangiogram (PTC) (Diament et al. 1985). The most common indications for PTC is obstructive jaundice resulting from either a malignancy, most commonly rhabdomyosarcoma of the bile ducts or pancreas and neuroblastoma, or post liver transplantation. Cholithiasis is less frequently a causative agent (Lorenz et al. 2001 Roebuck and Stanley 2000 Rose et al. 2001). Cholangitis, which is a relatively common indication for PTC in adults, is rarely seen in children. 

The advantage of internal-external biliary drainage over external biliary drainage is first of all that it re-establishes the flow of bile into the duodenum. 

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