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Bile is an isotonic aqueous solution of bile acids, cholesterol, phospholipids, bile pigments and inorganic electrolytes. It is secreted by the hepatocytes into the bile canaliculi and modified in the bile ductules or ducts. The three main processes identified in the generation of bile flow are: 1. Active transport of bile acids from blood into bile canaliculi. This is responsible of the bile acid-dependent canalicular bile flow. Coupling between water flow and bile acid secretion is probably effected mainly through an osmotic mechanism. There is evidence that water flows (at least in part) through the interhepatocytic junctions. The bile acid-dependent flow accounts for 30 to 60% of spontaneous basal bile flow. 2. A canalicular, bile acid-independent secretion, probably due to transport into bile of organic solutes (glutathione) and inorganic electrolytes. This fraction of bile flow is stimulated by phenobarbital. It represents 30 to 60% of basal bile flow. Normal canalicular bile flow also depends on the integrity of intracellular cytoskeletal organelles, mostly microfilaments. 3. Reabsorption and secretion of fluid and inorganic electrolytes by the ductules and ducts. Secretion chiefly occurs in response to secretin and represents 30% of basal bile flow. Although several ion transport systems have been identified on the biliary epithelial cells (in particular a Na+/H+ exchange, a Na+:HCO3- symport and a CI-/HCO3- exchange), the cellular mechanism of secretion is not known. Abnormalities of bile duct function may account for the liver disease of cystic fibrosis, but these abnormalities have not been characterized.

The authors describe a case of clinical, echocardiographic and haemodynamic adiastole in a man with severe rheumatoid arthritis with a previous history of pericardial effusion. The adiastole was mixed, fibrous pericarditis, confirmed by ultra fast CT scan and at surgery; myocardial adiastole was suspected on finding thickening of the ventricular walls (in the absence of hypertension and coronary artery disease) and, unfortunately, confirmed by the persistence of adiastole despite very satisfactory pericardectomy. The authors underline the involvement of the three cardiac tunics in rheumatoid arthritis and the value of different diagnostic methods in the differentiation between constrictive pericarditis and restrictive cardiomyopathy.

The aim of this study was to evaluate the sensitivity and specificity of the ultrasound intrahepatic bile duct wall comet-tail artifact for the diagnosis of biliary disease.All subjects who underwent upper abdominal ultrasound examination were included in the study over an 18-month period. The presence or absence of the comet-tail artifact (that is hyperechoic pattern with several parallels lines, constant, lining on the intrahepatic biliary ducts) was noted.Fourteen thousand four hundred and ninety-eight patients were included. The comet-tail artifact was only found in 10 of the 14 211 patients without biliary tract disease (99.9% specificity), but in 35 of the 287 patients with biliary disease (12.2% sensitivity). The positive predictive value for the diagnosis of biliary tract disease was 77.7%. The artifact was associated with an angiocholitis in 83% of the patients.Despite its low sensitivity, the sonographic comet-tail artifact of the intrahepatic bile duct wall was strongly correlated with the presence of biliary disease. This artifact may be related to an enlargement of the bile duct wall.