Effect of glycoursodeoxycholate on precipitation of calcium carbonate

The potential role of bile salts in preventing calcium carbonate precipitation was investigated by studying their interaction of Ca2+ and their inhibitory effects on calcium carbonate formation. Glycochenodeoxycholate micelles bound more calcium than did glycocholate. At bile salt concentrations exceeding 12.5 mM, glycoursodeoxycholate bound calcium as well as glycochenodexycholate did. Similar results for calcium binding were observed in mixed micelles of bile salts and lecithin. In bicarbonate (25 or 50 mM) and CaCl2 (10 mM) solutions, calcium carbonate formation was inhibited by the bile salts. Glycoursodeoxycholate and glycochenodeoxycholate (25 mM) prevented calcium carbonate formation which was delayed by glycocholate. This effect is not due to differences between both series of bile salts for calcium binding since glycoursodeoxycholate or glycochenodeoxycholate (25 mM) more efficiently prevented calcium carbonate precipitation than did 35 mM glycocholate in spite of the same Ca2+ binding. These results suggest that some bile salts may have a specific role in preventing calcium precipitation in bile. The mechanism is unknown. The physical properties of glycoursodeoxycholate and glycochenodeoxycholate do not support a role for CaCO3 precipitation in gallstone calcification during litholytic therapy.

Biliary excretion of latamoxef and N-methyltetrazolethiol in humans and rats

The biliary excretions of latamoxef and N-methyltetrazolethiol (NMTT) were studied in patients with T-tubes inserted in their common bile ducts, and in bile fistulated male rats. The highest concentrations of latamoxef and NMTT in 6 patients with cholelithiasis were obtained 1-2 h after intravenous injection of a single 1-g dose, and the mean peak values were 66.2 and 0.85 microgram/ml, respectively. The values in patients with gallbladder carcinoma or pancreas head carcinoma were much lower than those with cholelithiasis. The biliary excretions of latamoxef and NMTT in rats were much higher and faster than in humans, with the highest levels being obtained within 30 min after injection. About 20% of the injected dose was recovered as latamoxef and 4% as decomposed materials in 2.5 h after injection. Latamoxef was not decomposed in human or rat bile when kept at -20 degrees C for 4 weeks if the pH was adjusted to 6; some decomposition occurred (10-20%) if the pH was not adjusted.

Effect of dietary cholesterol on biliary lipids in patients with gallstones and normal subjects

The purpose of this study was to determine the effect of dietary cholesterol on biliary lipids in subjects with and without gallstones. Twelve patients with asymptomatic gallstones (six men, six women) were assigned diets containing 500, 750, and 1000 mg cholesterol daily for 3-wk periods in random sequence. Seven healthy women similarly were assigned diets containing 500 and 1000 mg cholesterol daily. With increasing dietary cholesterol in patients with gallstones, biliary saturation indices and molar percents of cholesterol and phospholipids increased significantly while molar percent of biliary bile acids decreased significantly. With increasing dietary cholesterol in healthy women, the biliary saturation index and molar percent of cholesterol increased significantly; the mean saturation index exceeded unity on the diet containing 1000 mg cholesterol daily. In conclusion, augmented dietary cholesterol for brief periods increased biliary cholesterol saturation in subjects with and without gallstones.

Effect of mucous glycoprotein on nucleation time of human bile

The purpose of this study was to determine whether mucous glycoprotein is the nucleating factor responsible for the rapid in vitro nucleation time of gallbladder bile from persons with cholesterol gallstones. Ultracentrifugation and ultrafiltration of abnormal bile removed all detectable mucous glycoprotein, yet bile that had been filtered exhibited as rapid a nucleation time as unfiltered bile. When abnormal bile was heated to 95 degrees C for 60 min, nucleation time was significantly prolonged. Rapid nucleation time could be restored to heated abnormal bile by addition of small volumes of unheated bile. Purified human mucous glycoprotein accelerated nucleation time of human bile, but mucous glycoprotein from control patients was as effective as that from gallstone patients. There was a direct relationship between mucous glycoprotein concentration and effect on nucleation time. Mucous glycoprotein may be important in the early stages of stone formation, but it is probably not the agent responsible for the sharp discrimination between control bile and gallbladder bile from patients with cholesterol stones found in the in vitro nucleation time test. The markedly prolonged nucleation time of heated abnormal bile is preliminary evidence that the nucleating factor may be a heat-labile protein other than mucous glycoprotein.

Increases in gallbladder prostaglandin synthesis before the formation of cholesterol gallstones

Increased synthesis of prostaglandins in the wall of the gallbladder may play a role in the pathogenesis of cholesterol gallstones by mediating mucus hypersecretion and thereby accelerating nucleation and the precipitation of cholesterol-supersaturated bile. We induced gallstones in prairie dogs and guinea pigs by feeding a cholesterol-supplemented diet for periods as long as 6 weeks. Gallbladder prostaglandin synthesis was quantitated by specific radioimmunoassays that measured the amount of various prostanoids released from the gallbladder during in vitro incubation. The gallbladders of cholesterol-fed prairie dogs showed increased synthesis of prostaglandin E2, prostaglandin F2a, and thromboxane and increased concentrations of glycoprotein in gallbladder bile. These changes were evident as early as 2 weeks after institution of the cholesterol diet, although cholesterol gallstones did not form until 4 or more weeks. In contrast, cholesterol feeding of the guinea pig did not induce cholesterol supersaturation. In this species pigment gallstones formed, probably as a result of a cholesterol-induced hemolytic anemia, and gallbladder mucus hypersecretion did not occur. Pigment gallstone formation in the guinea pig was associated with an increase in prostacyclin synthesis, but the synthesis of prostaglandin F2a and thromboxane was decreased. Increased prostaglandin synthesis may contribute to the formation of cholesterol gallstones but does not appear to participate in pigment gallstone formation.

An X-ray diffraction study of the crystalline composition of gallstones

The crystalline composition of gallstones removed from 30 patients from southwestern Finland was determined by the X-ray powder method. A total of eight crystalline compounds, varying from one to four per stone, were identified. Anhydrous cholesterol was by far the most abundant compound, occurring in 29 patients (97%), and calcium salts occurred in half the material studied. The stones could be classified on the basis of crystalline composition: pure cholesterol stones (40%), stones of cholesterol and calcium carbonate (37%), stones of cholesterol and sodium chloride or/and calcium palmitate (20%), and a stone of apatite and calcium carbonate (3%). The average amount of crystalline components per stone was as follows: cholesterols, 82%; calcium carbonates, 14%; and the rest, apatite, calcium palmitate, and sodium chloride. The crystalline composition of the stones related to the sex and age of the patients indicated several trends, including the occurrence of calcium carbonates in the stones of patients over 50 years of age and their simultaneous occurrence in small stones and with the cholesterols. Calcium palmitate was also more frequently present in the calculi of male patients.

Biliary lipid output and bile acid kinetics in cholesterol gallstone disease. Evidence for an increased hepatic secretion of cholesterol in Swedish patients

Sweden has one of the highest incidences of gallstone disease in the Western world. It is therefore important to characterize the mechanisms responsible for the formation of cholesterol gallstones in this population. In the present study, we have determined the kinetics of the two primary bile acids, cholic acid and chenodeoxycholic acid, and the hepatic secretion rates of the biliary lipids in 21 normolipidemic, nonobese gallstone patients (13 with functioning and 8 with nonfunctioning gallbladder) and in 23 healthy controls. The cholesterol saturation of fasting gallbladder bile averaged 110% in the gallstone patients with functioning gallbladder and 82% in the controls. The pool sizes of cholic acid and chenodeoxycholic acid were reduced by about 40% in the two groups of gallstone patients, whereas the rates of synthesis were close to normal. The fractional catabolic rate of both bile acids was increased in both groups of gallstone patients. The gallstone patients with functioning gallbladder had an increased (about 50%) cholesterol secretion but normal bile acid and phospholipid secretion rates. In the gallstone patients with nonfunctioning gallbladder the secretion rates of biliary lipids were not significantly different from those of the controls. The ratio between cholesterol and bile acids was about 50% higher in the gallstone patients with functioning gallbladder than in the controls or in those with nonfunctioning gallbladder. The results indicate that the hepatic secretion of cholesterol is an important determinant for the development of saturated gallbladder bile in Swedish gallstone patients.

Biliary squalene levels in hepatobiliary disease

Following overnight fasting, biliary levels of squalene, bile salts, cholesterol and phospholipid were estimated using human bile obtained with a duodenal double lumen catheter after administration of caerulein. While the squalene level in B-bile was 6.86 microM in the control group, it fell significantly in patients with parenchymal liver diseases, especially liver cirrhosis. There was no significant change in the level in patients with cholelithiasis. Biliary squalene concentration showed a significant correlation with concentrations of bile salts, cholesterol and phospholipid. These results substantiate the possibility that the biliary squalene level reflects sterol metabolism in the liver.

Portal venous bile acids in cholesterol gallstone disease: effect of treatment with chenodeoxycholic and cholic acids

We determined the serum concentrations of cholic, chenodeoxycholic and deoxycholic acids in portal and peripheral venous blood in 9 gallstone-free patients and 39 patients with cholesterol gallstones during standardized cholecystectomy. An accurate and specific gas chromatographic-mass spectrometric technique was used. The portal venous concentration of total bile acids was similar in gallstone-free and untreated gallstone patients (n = 20); there was no evidence of a reduced hepatic uptake of bile acids in the latter. Treatment with cholic acid (n = 10) was associated with a 70% increase in cholic acid and normal concentration of total bile acids. In chenodeoxycholic acid-treated patients (n = 9), the portal venous concentration of this bile acid was increased 3-fold; total bile acids were increased about 60%. The estimated hepatic uptake of cholic acid was slightly decreased during chenodeoxycholic acid treatment. The results indicate that neither bile acid inflow to the liver nor hepatic bile acid uptake is reduced in fasting patients with cholesterol gallstones, and treatment with chenodeoxycholic acid increases fasting inflow of bile acids to the liver. The latter may contribute to unsaturation of fasting hepatic bile during treatment with chenodeoxycholic acid.

Chemical composition of biliary calculi in relation to the pattern of biliary disease in Singapore

The chemical composition of biliary calculi from 25 Singapore patients operated upon over a three month period was determined by a microanalytical technique and equilibrium swelling tests. Twelve patients had biliary calculi confined to the gallbladder and the main component of six calculi was cholesterol. In the other 6 patients, the dark brown to black pigment calculi contained bilirubin and calcium and a small quantity of cholesterol, but the chief component was an insoluble pigment with the swelling characteristics of a bilirubin polymer. These cholesterol and pigment calculi have similarities in composition to gallstones of Western patients. In 13 patients with cholangitis, the brown, soft pigment calculi found in the dilated bile ducts (and also concurrently in the gallbladder in 5 patients) had bilirubin as the main component. Fatty acid was frequently present. The insoluble pigment component was considerably less but the lower swelling ratio suggested more cross linkage compared with black gallbladder stones. Differences in chemical composition between pigment gallbladder and bile duct calculi support the concept that Western type cholelithiasis and Oriental cholangitis occur as separate disease entities in Singapore patients.

Rapid and accurate reversed-phase high-performance liquid chromatographic determination of conjugated bile acids in human bile for routine clinical applications. Therapeutic control during gallstone dissolution therapy

This paper introduces a new method to detect the taurine and glycine conjugates of five different bile acids (cholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid and lithocholic acid) in human bile. Advantages of this method are sufficient separation of compounds within a short period of time and a high rate of reproducibility. Using a mobile phase gradient of acetonitrile and water, modified with tetrabutylammonium hydrogen sulphate (0.0075 mol/l), we were able to maximize the differentiation between ursodeoxycholic acid and lithocholic acid, which is of primary interest during conservative gallstone dissolution therapy. Use of this gradient reduced analysis time to less than 0.5 h. Recovery rates for this modified method ranged from 94% to 100%, and reproducibility was 98%, sufficient for routine clinical applications.

Cancer of the gallbladder in Bolivia: suggestions concerning etiology

In order to investigate the very high incidence of gallbladder cancer in Bolivia, a series of patients with gallbladder cancer and/or cholelithiasis from a hospital in La Paz was compared to a series of patients with cholelithiasis from Philadelphia. Each group demonstrated a similar female predilection. Bolivian patients with gallbladder cancer were older than patients with cholelithiasis who, in turn, were older than the general population (p less than 0.001). Racial differences demonstrated previously were confirmed. Bolivian gallstones were uniformly cholesterol in type, in contrast to the US series, in which 27% of patients had black pigment stones. Bile specimens obtained from Bolivian patients with cholelithiasis had a lower concentration of bile salts, phospholipids, and cholesterol than bile specimens from US cholelithiasis patients (p less than 0.01, less than 0.001, and less than 0.001, respectively). These biochemical differences may help to explain the differing incidence of cholelithiasis and gallbladder cancer in the US and Bolivia.

Mass spectrometry identification of biliary bile acids in bile from patients with gallstones before and during treatment with chenodeoxycholic acid. An ancillary study of the National Cooperative Gallstone Study

The chemical structure of individual bile acids in 255 duodenal bile samples obtained from patients with radiolucent gallstones before and during treatment with chenodeoxycholic acid (375 or 750 mg/day) was determined by coupled gas chromatography/mass spectrometry. The two primary bile acids, cholic acid and chenodeoxycholic acid, and their metabolic products, deoxycholic acid, lithocholic acid, and ursodeoxycholic acid, were present in all bile samples and constituted greater than 97% of all bile acids. In pretreatment samples, the 12-oxo derivative of deoxycholic acid (3 alpha-hydroxy-12-oxo-cholanoic acid) was the next most abundant bile acid, being present in 62% of the samples; the average concentration was 1%, but three individuals had 6% to 8% of this bile acid. The 7-oxo derivative of chenodeoxycholic acid was also present in the majority of samples, but at a lower proportion (0.3%); five individuals had 2% to 3%. The 7-oxo derivative of cholic acid was present in a minority of samples (37%) in trace concentrations; isodeoxycholic acid and the 3-oxo derivatives of chenodeoxycholic acid and deoxycholic acid were also present in trace amounts. Four patients had 1% to 11% ursocholic acid in bile. During treatment with chenodeoxycholic acid, bile became enriched in it in direct relation to dosage; the concentration of its bacterial metabolites increased, and the proportion of cholic acid and its bacterial metabolites showed a reciprocal decrease. No unusual bile acids appeared, indicating that treatment with these doses of chenodeoxycholic acid does not result in the occurrence of additional uncommon bile acids in bile. It is suggested that the paucity of uncommon bile acids in bile, which contrasts strikingly with the great variety of uncommon bile acids known to be present in urine and feces, is the result of two factors: (1) the conversion of uncommon bile acids to common bile acids by reduction, hydroxylation, or epimerization during hepatic passage; and (2) efficient hepatic transport of common but not uncommon bile acids into bile.

Effect of dietary taurine on cholesterol gallstone formation and tissue cholesterol contents in mice

The inhibitory effect of dietary taurine on cholesterol gallstone formation was studied using male mice of Jcl:ICR strain. Mice were provided three kinds of semi-purified diet; a cholesterol-free diet (standard), a lithogenic diet containing 0.5% cholesterol and 0.25% sodium cholate (C-CA), and a lithogenic diet supplemented with 5% taurine. The changes of total cholesterol in serum, cholesterol mass in the liver and the gall bladder, and gallstone incidence were studied as a function of time. Gallstone formation was observed only in the mice fed on the C-CA diet for more than 3 weeks. The changes of serum cholesterol concentration were not consistent with gallstone formation. The cholesterol mass of the liver in taurine-supplemented mice decreased after the 3rd week. Cholesterol content of the gall bladder increased with cholesterol gallstone formation. Therefore, the inhibitory effect of dietary taurine on cholesterol gallstone formation may be related to the decrease in cholesterol content of the liver.

The precipitation of calcium carbonate polymorphs in vitro at 37 degrees C

In order to determine some of the factors that affect the formation of the three polymorphs of calcium carbonate in gallstones, its precipitation from undisturbed solutions containing calcium chloride and sodium bicarbonate was studied. The variation in the amount of calcium carbonate formed with time was studied by weighing the precipitate, and the percentages of calcite, vaterite, and aragonite were determined by x-ray diffraction (XRD) analysis. The effects of additives and stirring were noted. Minor changes in conditions were sufficient to affect the formation of the polymorphs, and all three polymorphs could be found simultaneously in some solutions. It is suggested that no great differences in precipitating conditions need to be postulated to account for the presence of different polymorphs in gallstones. Aragonite seems to be formed slowly in undisturbed conditions.

Identification of bile alcohols in human bile

Human gallbladder bile was examined for bile alcohols. Following isolation and hydrolysis, the bile alcohols were analyzed by capillary gas-liquid chromatography-mass spectrometry. The following bile alcohols were identified with certainty by direct comparison with reference standards: 5 beta-cholane-3 alpha,-7 alpha,23,24-tetrol; 5 beta-cholane-3 alpha,7 alpha,12 alpha,24-tetrol; 24-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol; 27-nor-5 beta-cholest-25-ene-3 alpha,7 alpha,-12 alpha,24-tetrol; 3 alpha,7 alpha,12 alpha-trihydroxy-27-nor-5 beta-cholestan-24-one; 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol; 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol; 5 beta-cholestane-3 alpha,7 alpha,24-triol; 5 beta-cholestane-3 alpha,7 alpha,25-triol; 5 beta-cholestane-3 alpha,7 alpha,26-triol; 5 alpha-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,26-tetrol; (24R)- and (24S)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentols; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26-pentol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,-25,26-pentol; 5 beta-cholestane-3 alpha,7 alpha,12 alpha,26,27-pentol; 26-methoxy-5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol. There also existed two norcholestanetetrols and three cholestanetetrols with two hydroxyl substituents on the nucleus and two in the side chain. The human biliary bile alcohols occurred mainly as sulfate esters and in lesser amounts as glucuronoconjugated and unconjugated forms. The amount of total bile alcohols was about 0.9 mg (0.7-1.2 mg) in 1 g of bile solid, or 0.16 mumol (0.07-0.24 mumol) in 1 ml of gallbladder bile.