Mechanism of deoxycholic acid stimulation of the rabbit colon.

Previous studies showed that deoxycholic acid (DCA) stimulated migrating action potential complexes (MAPC) in the colon. The aim of this study was to clarify the mechanism of DCA-stimulated colonic motility. Myoelectrical and contractile activity were measured in New Zealand White rabbits from a loop constructed in the proximal colon. During the control period, slow waves were present at a frequency of 10.8 +/- 0.5 cycle/min and there were 1.5 +/- 0.5 MAPC/ h. After adding DCA (16 mM) to the loop the slow wave activity was unchanged. However, MAPC increased to 15.1 +/- 2.4 MAPC/h (P less than 0.001). MAPC activity was not stimulated in the colonic smooth muscle outside the loop. The intraluminal addition of procaine or tetrodotoxin to the colonic loop inhibited the DCA-stimulated increase in MAPC activity (0.2 +/- 0.2 MAPC/h) (P less than 0.005). Intravenous administration of atropine or phentolamine also inhibited MAPC activity that had been stimulated by DCA (P less than 0.005). Pretreatment with 6-hydroxydopamine also inhibited an increase in MAPC activity. Propranolol, trimethaphan camsylate, or hexamethonium had no effect on DCA stimulation of MAPC activity. Although the concentration of bile salt increased in the mesenteric venous outflow from the colonic loop, the intravenous administration of bile salt did not stimulate colonic MAPC activity. These studies suggest: (a) the action of DCA on smooth muscle activity is a local phenomenon, (b) the increase in MAPC activity is dependent on intact cholinergic and alpha adrenergic neurons, and (c) an increase in the concentration of bile salts in the serum is not associated with an increase in colonic MAPC activity.

Kinetic analysis of biliary lipid excretion in man and dog.

To understand better the mechanisms involved in biliary lipid excretion and to evaluate their role in cholesterol gallstone formation, the rates of biliary excretion of bile salts, cholesterol, and phospholipids were measured in two species, man and dog. Seven cholecystectomized patients with balloon-occludable reinfusion T-tubes were studied during intact and interrupted enterohepatic circulation and four cholecystectomized dogs were studied during interrupted enterohepatic circulation. In man and dog both cholesterol and phospholipid outputs were hyperbolically related to bile salt output by the equation y = x/(a + bx). The output curves intersected the origin and showed an initial rapid rise, followed by a slower increase to a maximum, suggesting a rate-limited mechanism. The shape of the curves permitted calculation of the theoretical maximal outputs and the rates of rise to those outputs. Comparison of these values showed that in both man and dog phospholipid output was greater than cholesterol output and that cholesterol and phospholipid were excreted at different rates. These studies (a) indicate that cholesterol, phospholipids, and bile salts are not excreted in a fixed relationship and (b) demonstrate the usefulness of the derived theoretical maximal lipid output, and the rate of rise of lipid excretion to a maximum, in evaluating the kinetics of biliary lipid excretion.

Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface.

Triketocholanoic (dehydrocholic) acid. Hepatic metabolism and effect on bile flow and biliary lipid secretion in man.

[24-(14)C]Dehydrocholic acid (triketo-5-beta-cholanoic acid) was synthesized from [24-(14)C]cholic acid, mixed with 200 mg of carrier, and administered intravenously to two patients with indwelling T tubes designed to permit bile sampling without interruption of the enterohepatic circulation. More than 80% of infused radioactivity was excreted rapidly in bile as glycine- and taurine-conjugated bile acids. Radioactive products were identified, after deconjugation, as partially or completely reduced derivatives of dehydrocholic acid. By mass spectrometry, as well as chromatography, the major metabolite (about 70%) was a dihydroxy monoketo bile acid (3alpha,7alpha-dihydroxy-12-keto-5beta-cholanoic acid); a second metabolite (about 20%) was a monohydroxy diketo acid (3alpha-hydroxy-7,12-di-keto-5beta-cholanoic acid); and about 10% of radioactivity was present as cholic acid. Reduction appeared to have been sequential (3 position, then 7 position, and then 12 position) and stereospecific (only alpha epimers were recovered). Bile flow, expressed as the ratio of bile flow to bile acid excretion, was increased after dehydrocholic acid administration. It was speculated that the hydroxy keto metabolites are hydrocholeretics. The proportion of cholesterol to lecithin and bile acids did not change significantly after dehydrocholic acid administration. In vitro studies showed that the hydroxy keto metabolites dispersed lecithin poorly compared to cholate; however, mixtures of cholate and either metabolite had dispersant properties similar to those of cholate alone, provided the ratio of metabolite to cholate remained below a value characteristic for each metabolite. These experiments disclose a new metabolic pathway in man, provide further insight into the hydrocholeresis induced by keto bile acids, and indicate the striking change in pharmacologic and physical properties caused by replacement of hydroxyl by a keto substituent in the bile acid molecule.

Protective action of luminal bile salts in necrotizing acute pancreatitis in mice.

Bile salts in the intestinal lumen act to inhibit the release of cholecystokinin (CCK). Recent studies have shown that CCK may play a permissive role in the development of acute pancreatitis. In this study, the amount of luminal bile salts in female Swiss Webster mice was either decreased by feeding 4% (wt/wt) cholestyramine or increased by feeding 0.5% sodium taurocholate for 1 wk. Plasma levels of CCK were stimulated by cholestyramine and inhibited by taurocholate. Then, acute pancreatitis was induced either by caerulein injections, or by feeding a choline-deficient, ethionine-supplemented (CDE) diet. Feeding of cholestyramine significantly decreased survival from 25% to 0% in the CDE pancreatitis, and increased the magnitude of elevation of serum amylase levels and the extent of pancreatic necrosis in both models of pancreatitis; CCK-receptor blockade with CR-1409 completely abolished the adverse effects of cholestyramine. In contrast, feeding of taurocholate significantly increased survival to 100% and decreased the elevation of serum amylase and pancreatic necrosis; CCK-8 antagonized these actions of taurocholate. Luminal bile salts appear to provide a physiologic protection against necrotizing pancreatitis, at least in part, both by inhibiting the release of CCK and by promoting resistance of the pancreas to CCK excessive stimulation in vivo.

Current therapy of chronic liver disease.

The study of chronic liver disease has been hampered by insufficient information relative to the pathogenesis of the many forms of hepatitis. Consequently, well-designed treatment strategies are frequently lacking. Wilson's disease is characterised by excessive copper accumulation in the liver and other organs. While d-penicillamine is clearly effective, many patients may not tolerate its many adverse effects. Trientine, oral zinc and unithiol have all shown promise as therapeutic alternatives. Autoimmune chronic active hepatitis responds well to prednisone and azathioprine. Cyclosporin has also produced clinical improvement in several case reports but no comparison has yet been made with the current standard therapy. Recombinant interferon-alpha (IFN alpha) has demonstrated the ability to inhibit hepatitis B viral replication, and the combination of oral corticosteroids followed by IFN alpha is more effective than either agent alone in eliminating viral replication in patients with chronic active hepatitis B. Currently, primary sclerosing cholangitis (PSC) has no standard medical management, but corticosteroids and methotrexate may each have a future role in its treatment. Drug treatment for primary biliary cirrhosis (PBC) has been disappointing, and early reports of success with d-penicillamine were not confirmed in large well-controlled trials. While some reports of improvement with several agents have been described, larger studies are still needed. Alcoholic liver disease continues to be associated with significant morbidity and mortality and numerous investigators have researched several different medical avenues of treatment. Success reported with androgens and the antithyroid agent propylthiouracil in alcoholic liver disease will need confirmation by other research before these agents can be recommended for routine use. Finally, colchicine may prove to be effective in slowing the rate of fibrosis in cirrhosis, but this has yet to be conclusively proven.

Efficacy of a motilin receptor agonist (ABT-229) for the treatment of gastro-oesophageal reflux disease.

BACKGROUND: ABT-229 is a potent motilin agonist without significant antibiotic activity. It has been shown to improve gastric emptying in humans and to increase lower oesophageal sphincter pressure in cats. AIM: To assess the efficacy of four different doses of ABT-229 (1.25 mg, 2.5 mg, 5 mg, 10 mg b.d.) compared to placebo in the treatment of gastro-oesophageal reflux disease, and to determine its safety in patients with gastro-oesophageal reflux disease. METHODS: In a double-blind, multicentre study, 324 patients with heartburn were randomized to receive four different doses of ABT-229 or placebo for 8 weeks. The efficacy was evaluated by Patient Symptom Questionnaire, daily diary, endoscopy and global evaluation of efficacy. RESULTS: There were no statistically significant improvement scores for any of the ABT-229 treatment groups vs. the placebo group in any of the efficacy parameters. Reflux symptom scores were significantly worse after treatment in the dyspeptic group. ABT-229 appeared to be well tolerated and safe in total daily doses up to 20 mg. CONCLUSION: ABT-229 appears to have limited, if any, clinical utility in the treatment of gastro-oesophageal reflux disease.

The epidemiology of cancer of the extra-hepatic biliary tract in Bolivia.

Data on patients with cancer of the gall bladder and cancer of the extra-hepatic bile ducts were obtained from the tumour registry in La Paz, Bolivia. Incidence rates were calculated using the Bolivian census data and compared to US incidence data from the Third National Cancer Survey. The age and population standardized incidence rates for cancer of the gall bladder in Bolivia were 5.3/100,000 males/year and 10.3/100,000 females/year. Comparable US rates were 1.0/100,000 males/year and 2.1/100,000 females/year. The age and population standardized incidence rates for cancer of the extra-hepatic bile ducts in Bolivia were 1.1/100,000 males/year and 4.1/100,000 females/year. Comparable US rates were 1.6/100,000 males/year and 1.0/100,000 females/year respectively. Both diseases occurred at younger ages in Bolivia than in the US and both showed marked racial variation. Differences in disease incidence between Bolivia and the US could not be fully explained by differences in age, sex, or racial distributions. Studies designed to investigate the causes of this remarkable variation in disease incidence could provide important clues to disease aetiology.

Primary sclerosing cholangitis and pregnancy.

Primary sclerosing cholangitis is a chronic, fibrosing, inflammatory disorder of unknown etiology affecting the biliary tree. We describe a case of a pregnancy complicated by this condition. Remarkably, maternal cholestasis improved with advancing gestation. Despite a marked elevation of bile acid levels in cord blood, the patient was delivered of a healthy term infant. The principles of management and potential effects of primary sclerosing cholangitis on pregnancy care are discussed.

Cesium cholate: determination of X-ray crystal structure indicates participation of the ring hydroxyl groups in metal binding.

The crystal structure of cesium cholate, C(24)H(36)(OH)(3) COOCs has been determined with three-dimensional X-ray diffractometer data. It crystallized in the monoclinic space group P2(1) with unit-cell dimensions a = 11.543(5) A, b = 8.614(3) A, and c = 12.662(5) A, beta(deg) = 107.95(2), V = 1197.7 A(3) and Z = 2. The atomic parameters were refined to a final r = 0.0269 and R(omega) = 0.0280 for 2342 observed reflections. Each Cs(+) is coordinated to 7 oxygen atoms from 5 different cholate anions with Cs-O distances ranging from 2.957(4) A to 3.678(5) A. In this crystal, 5 cholates are coordinated with 1 Cs(+), and 5 Cs(+) are coordinated with 1 cholate anion. Carboxyl and all the 3 ring hydroxyl groups of cholate anion participate in binding to Cs(+) simultaneously, and there is no water molecule coordinated with the Cs(+). The pattern of successive rows arranged with polar (p) and non-polar (n) faces in apposition leads to the formation of a sandwich sheet structure with polar and non-polar channels. The Cs ions lie within the polar interior of the sandwich. The H-bond network is reorganized in forming cesium cholate from cholic acid. All the oxygen atoms in cholate anion are involved in H-bonding reciprocally or with water molecules to form an extensive 3-dimensional network of H-bonds. Compared with cholic acid and other similar type of steroids, the coordination structure and H-bonding of Cs cholate crystal are distinct.

An animal model of pigment cholelithiasis.

Pigment stones of high calcium content were induced in male hamsters of the Harlan Sprague-Dawley strain fed a nutritionally adequate semipurified diet for a period of 14 weeks. The diet contained moderate amounts of cholesterol (0.30 percent) and ethinyl estradiol (15 micrograms/day per animal). At sacrifice, the incidence of pigment stones was 50 percent. When stones were present, they were in the form of numerous black amorphous rods about 0.1 to 0.4 mm in length. Infrared analysis of the dried stones indicated the following composition: calcium phosphate 26.7 percent, calcium bilirubinate 12.8 percent, cholesterol 15.1 percent, and protein 45.4 percent. Pigment stones were associated with an elevated biliary total calcium level (probably induced by the dietary cholesterol) and a paradoxic decrease in the biliary total bilirubin level. The lithogenic diet produced marked elevations in liver and plasma cholesterol levels and cholesterol saturation of bile, but no cholesterol crystals or stones were observed. The accumulation of elevated levels of cholesterol in the livers of the experimental animals produced mild to moderate hepatotoxicity. The precise mechanism of the dietary induction of pigment stones in this hamster model remains to be elucidated.

Reminding as a basis for temporal judgments.

In the normal course of events, some events bring to mind earlier events. This reminding or, in the context of list learning experiments, study-phase retrieval can serve as a basis for the accurate judgment of the relative recencies of the two events in question. In this article, evidence for this position is presented in three experiments. By manipulations of encoding using visual imagery instructions and word associations, appropriate conditions were arranged for reminding to occur. The results of all three studies support the position that reminding provides a direct basis for later judgments of the relative recency of events.

Primary malignant fibrous histiocytoma of the liver MRI findings.

Primary malignant fibrous histiocytoma (MFH) is an unusual tumor which involves the deep fascia or skeletal muscles of the extremities or retroperitoneum. It rarely arises in the liver and, to our knowledge, the MRI appearance of primary MFH of the liver has never been reported. We present a patient with primary MFH of the liver and discuss the findings on MRI, CT, and angiography.

Inhibitors present in blood do not inhibit PCR from buccal cell preparations: case report.

BACKGROUND: Hemochromatosis is a common disease that is characterized by high ferritin levels and/or high iron saturation and mutations in two alleles. MATERIAL AND METHODS: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) is often performed on DNA extracted from blood since blood yields high concentrations of DNA. However, inhibitors can cause PCR failure in DNA extracted from blood thus preventing a molecular diagnosis. RESULTS: This report describes a case where multiple blood draws resulted in unamplifiable DNA. Subsequently, a buccal cell sample was collected and extracted. DNA extracted from the buccal cells yielded amplifiable DNA in contrast to DNA extracted from the patient's blood. In addition, the patient was identified as having a homozygous mutation for one allele of the hemochromatosis gene. CONCLUSION: These results suggests that a buccal cell DNA extraction may be useful in cases where blood samples contain inhibitory substances for PCR.

The interaction of Cu2 + ions and NaDC micelles.

By mixing an aqueous solution of CuCl2 with an NaDC aqueous solution of various concentration and initial molar ratio, seven coordinated samples with distinct appearances and characters were obtained. Their structures and components were investigated by FT-IR spectroscopy, EXAFS (the extended X-ray absorption fine structure), thermal analysis, X-ray diffraction, laser light scattering, TEM (transmission electron micrograph), element analysis and ICP (inductively coupled plasma) analysis. The following conclusions were given: (1) The complexes of Cu2+-NaDC with distinct appearances and properties were synthesized. (2) After Cu(DC)2 dissolved in NaDC aqueous solution, larger micelles (30-90 nm diameter) formed in the supernate, it is a mixed micelle with Cu(DC)2 and NaDC. So these micelles are a new kind of micelle containing two kinds of metal ions. This is a new result using metal ions as bridges to form micelle. (3) According to the different concentration of Cu2+ to NaDC, the complexes formed as gel or poly-crystals. Both the composition of gel complexes and the coordination structure of carboxyl groups with metal ions varied with the initial molar ratio of Cu2+ to Na+. The gel complexes exhibits the non-stoichiometric character. (4) These results are in agreement with physiological condition. All the different states such as gel, precipitate, micelles of various structures are present in bile of gallbladder. We can suggest an ideal model of the interaction between Cu2+ and bile salts in vivo.

[Molfig, a software for displaying the structure and vibration of molecule].

A Molfig software has been developed for displaying the structure and vibrational mode of molecule in our lab. Various functions and a friendly interface are equipped in the software. The testing results showed that the software may enhance our understanding of the relationship between the vibrational behavior and the structure of molecules.