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.

Studies on the pathogenesis of pigment gallstones in hemolytic anemia: description and characteristics of a mouse model.

The pathogenesis of hemolysis-induced gallstones was studied in mice with a hereditary hemolytic disease called normoblastic anemia (genotype nb/nb) and in their normal controls (genotype +/+). Infrared spectroscopy demonstrated that spontaneously formed gallstones from nb/nb mice were nearly identical to stones from patients with chronic hemolysis as the result of sickle cell disease, and both mouse and human stones strikingly resembled synthetic calcium bilirubinate. 57% of 115 nb/nb mice, but none of 109 control mice, developed calcium bilirubinate pigment gallstones (P < 0.001). The incidence of luminal gallstones in nb/nb mice was both sex and age dependent. Female nb/nb mice formed stones twice as frequently as male nb/nb mice (P < 0.001). Before 6 mo of age neither sex developed stones, but thereafter the incidence of stones increased with age. Neither hematocrit, reticulocyte count, nor total plasma bilirubin values, were useful in distinguishing between nb/nb mice with or without gallstones. In gallbladder bile, nb/nb mice with gallstones had higher concentrations of hydrogen ion, total bilirubin, calcium, and bile acids than nb/nb mice without stones. Although total unconjugated bilirubin was similar in both nb/nb groups, the ionized fraction of unconjugated bilirubin was higher in bile from nb/nb mice without stones than those with stones. In nb/nb mice, neutral mucin plugs and pigment concentrations were observed histologically in the glandular crypts of the gallbladder in 33% of nb/nb mice without stones and in 80% of nb/nb mice with luminal stones. This suggested that luminal pigment stone disease in mice with hemolysis may be preceded by microscopic precipitation of calcium bilirubinate in the glandular crypts of the gallbladder. These precipitates may then migrate into the lumen and grow by accretion.

Pigment gallstone disease.

Black and brown pigment gallstones are morphologically, compositionally, and clinically distinct. Black stones form primarily in the gallbladder in sterile bile and are associated with advanced age, chronic hemolysis, alcoholism, cirrhosis, pancreatitis, and total parenteral nutrition. Brown stones form not only within the gallbladder but also within the intrahepatic and extrahepatic ducts; they are uniformly infected with enteric bacteria and are usually associated with ascending cholangitis. Brown stones are related to juxtapapillary duodenal diverticula and are the predominant type of de novo common bile duct stones. Cholecystectomy is usually curative in black pigment stone disease, whereas stones often recur after cholecystectomy for brown stone disease. The pathogenesis of black stones is probably related to nonbacterial, nonenzymatic hydrolysis of bilirubin conjugates. At the pH of bile, this results in two monohydrogenated bilirubin anions that precipitate with calcium ions. Bilirubin monoconjugates that are increased in several conditions, such as Gilbert's syndrome and chronic hemolysis, may play a pivotal role in black stone formation as a source of unconjugated monohydrogenated bilirubin and as a possible co-precipitant with calcium. The precipitation of calcium carbonate and phosphate is influenced by local gallbladder factors. Brown pigment stones are formed in bile infected with enteric bacteria that elaborate hydrolytic enzymes: beta-glucuronidase, phospholipase A, and conjugated bile acid hydrolase. The resulting anions of bilirubin and fatty acids form insoluble calcium salts. We used nb/nb mice with a chronic hemolytic anemia as a model of hemolysis-induced black stone disease. The presence of 40% bilirubin monoconjugates in mouse gallstones indicated the importance of this moiety in the pathogenesis of black stones. Other data obtained by marrow transplantation experiments in mice revealed the relative importance of genotype versus the hemolytic anemia on determinants such as biliary bile acid composition and mucin secretory glands in the mouse gallbladder neck. Additional physical chemical studies of the interaction of unconjugated bilirubin in model bile solutions will be helpful in further delineating the pathogenesis of both black and brown pigment gallstones.

The apparent association constant of calcium and bilirubinate ions in Triton X-100 micelles.

Calcium bilirubinate [Ca(HB)2], a major component of pigment gallstones, rapidly precipitates from aqueous solutions, thereby precluding an accurate determination of the apparent association constant (K') of calcium (Ca2+ and monohydrogenated bilirubinate (HB) ions. In this study, we determine the K' in solutions of Triton X-100, a nonionic detergent with a critical micellar concentration of 0.01 g/dL, by analysis of spectral shifts, using a Hewlett-Packard diode array spectrophotometer. In the absence of Ca2+, 10 microM sodium bilirubinate (NaHB) solutions were incorporated into Triton X-100 micelles in 0.15 M NaCl, 0.10 M Tris Cl, pH 8, as evidenced by a progressive shift in the wavelength maximum (lambda max) of 10 microM HB from 438 to 458 nm in 0-0.1 g/dL (0-10 microM of micelles/L) Triton. Thus the lambda max plateau occurred with 1 mole of HB per micelle of Triton. As Ca2+, 0-90 microM, was added to 100 microM NaHB in 0.5 g/dL Triton X-100, there was a progressive downward shift in the lambda max of HB from 458 to 434 nm; an isosbestic point was present at 448 nm. A calibration curve using ratios of absorbance (Abs) 420/470 for known concentrations of Ca(HB)2 or NaHB was used to determine the mole fraction of Ca(HB)2. The spectral data were consistent with the equilibrium equation: Ca2+ + 2 HB = Ca(HB)2.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrointestinal angiodysplasia.

Angiodysplasia of the gastrointestinal tract is common in the population 60 years of age and older and may be the cause of acute and/or chronic bleeding. Colonic angiodysplastic lesions are presumed to be degenerative in nature, secondary to either intermittent obstruction of the submucosal veins or hypoxemia. The pathogenesis of upper intestinal angiodysplasia is most likely related to a degenerative process. The clinical presentation varies from an incidental finding in an otherwise asymptomatic person to occult bleeding or an acute massive hemorrhage. Endoscopy and angiography are useful diagnostic modalities. Management options include surgery, endoscopic obliteration, or angiographic embolization of an identified bleeding angiodysplastic lesion(s). In a subset of patients who have angiodysplasia associated with Osler-Rendu-Weber disease or chronic renal failure, hormonal therapy with estrogen-progesterone may be efficacious.

Pigment gallstone disease: Summary of the National Institutes of Health--international workshop.

This report summarizes the proceedings of the first National Institutes of Health--International Workshop on Pigment Gallstone Disease. The meeting held at the University of Pennsylvania in May, 1981 consisted of eight sessions in which the following aspects of pigment gallstone disease were discussed: (a) classification; (b) epidemiology; (c) radiographic assessment; (d) gallstone composition; (e) composition of bile; (f) pathogenesis; (g) animal models, genetics, and computer analysis, and (h) medical treatment. The interaction of participants interested in various aspects of pigment stone disease was stimulating. This workshop should be a major stimulus for future studies in this relatively neglected, but important area of biliary tract lithiasis.

Use and safety of aspirin in the chemoprevention of colorectal cancer.

Colorectal cancer is the third leading cause of cancer-related mortality and a significant public health problem in the United States. Aspirin and other nonsteroidal anti-inflammatory drugs reduced the incidence of colorectal cancers and related mortality by 30% to 60% as well as the incidence of colonic adenomas. This effect is presumably due to an inhibition of cyclooxygenase 2, an inducible enzyme involved in the synthesis of prostaglandins. Prostaglandins are increased in colorectal neoplasms. Aspirin's effect appears to be dose related and enhanced by long-term exposure. Two prospective studies, however, failed to show a protective benefit of aspirin in colorectal cancer. When used long term, aspirin has significant adverse effects and is poorly tolerated. The gastrointestinal toxicity of aspirin is dose related, but even low doses of aspirin (75 mg per day) when used regularly result in significantly higher gastrointestinal toxicity, manifested by melena, hematemesis, and peptic ulcer disease, in aspirin users compared with nonusers. Furthermore, some studies indicate an increased risk of hemorrhagic strokes in aspirin users. Presently, aspirin should not be recommended for the primary chemoprevention of colorectal cancer in the general population due to significant risks of serious cerebrovascular and gastrointestinal adverse effects associated with long-term aspirin use.

Pigment vs cholesterol cholelithiasis: clinical and epidemiological aspects.

This prospective study demonstrated that among 92 consecutive patients who underwent cholecystectomy for gallstones at an urban university hospital, 27% had pigment stones and 73% had cholesterol stones. Age, sex, and weight, but not race, were significant determinants of stone type. The mean hemoglobin, direct and total serum bilirubin, and fasting glucose concentrations were similar for each group. The presence of alcoholism, diabetes, thyroid disease, or heterozygous hemoglobinopathy did not influence stone type. The average patient with pigment stones is a lean man or woman 63 years old; in contrast the composite patient with cholesterol stones is a modestly overweight woman 43 years old.

Drugs for treatment of peptic ulcers.

Pharmacologic management of peptic ulcer disease continues to evolve with the introduction of diverse types of new therapeutic agents. The ideal aims of treatment of peptic ulcer disease are to relieve pain, heal the ulcer, and delay ulcer recurrence. This article provides a broad perspective on the pharmacology and therapeutic actions of antiulcer drugs. To date, no drug meets all goals of therapy. Drug treatment of peptic ulcers is targeted at either counteracting aggressive factors or stimulating the mucosal defense. Drugs that inhibit or neutralize gastric acid secretion include histamine H2-receptor antagonists, proton pump inhibitors, anticholinergics, prostaglandins, and antacids. H2-receptor antagonists have become first-line drugs for treatment of uncomplicated duodenal ulcers, gastric ulcers, prevention of ulcer relapse, and mild esophagitis. However, H2-receptor antagonists, like other gastric antisecretory/antiulcer drugs, have high rates of ulcer recurrence following discontinuation of therapy. They therefore need to be administered continuously in patients prone to such recurrences. Omeprazole has emerged as a major drug for the treatment of severe erosive esophagitis, refractory ulcers, and Zollinger-Ellison syndrome. The major disadvantage of proton pump inhibitors is the concern for their long-term safety. The roles of M1-antimuscarinic agents and antacids have not been fully defined. Misoprostol, effective for the treatment of gastric and duodenal ulcers, is now the only drug that prevents ulcers induced by nonsteroidal anti-inflammatory drugs. Mucosal protective drugs that do not inhibit gastric acid secretion include sucralfate and organic bismuth salts. Sucralfate is a nonsystemic, well-tolerated, effective drug for treatment of duodenal ulcers and prevention of duodenal ulcer relapse. The organic bismuth salt bismuth subcitrate is efficacious in the treatment of duodenal and gastric ulcers. Furthermore, it has also been established that it alters the course of ulcer recurrence. However, bismuth encephalopathy is a major toxicity concern that needs to be addressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Boerhaave's syndrome. Spontaneous formation of an esophageal-bronchial fistula.

Although Boerhaave's syndrome is usually a surgical emergency, we recently observed a 57-year-old man with a chronic Boerhaave's syndrome. Initially, he responded to conservative management. However, the spontaneous formation of an esophageal-bronchial fistula complicated his course. Pulmonary symptoms and weight loss prompted surgical intervention. We speculate that the patient's six-week clinical course before surgery was tolerated because the contamination of the mediastinum following the initial esophageal tear was well contained and allowed sufficient time for the spontaneous formation of an esophageal-bronchial fistula.

Milk of calcium bile. Evidence that gallbladder stasis is a key factor.

Milk of calcium bile is a rare disorder in which the gallbladder lumen is filled with a semisolid radiopaque material composed primarily of calcium carbonate. The etiology is unknown, although gallbladder stasis is believed to be a prerequisite. We report a case of milk of calcium bile in which preexisting gallbladder stasis was retrospectively evaluated by reviewing plain abdominal films and by using iodide as a marker for retained contrast. This latter approach was validated by demonstrating that obstructed gallbladders do not physiologically sequester iodide and that following oral cholecystography functioning gallbladders do not retain significant iodide for prolonged periods. In the case described, we propose that gallbladder stasis was present as long as 2 1/2 years prior to the diagnosis of milk of calcium bile.

Monoconjugated bilirubin is a major component of hemolysis-induced gallstones in mice.

The role of bilirubin conjugates in the formation of pigment gallstones is not known. In this study, we completely solubilized and then analyzed by high-performance liquid chromatography specimens of black pigment gallstones from eight nb/nb mice with hereditary hemolytic anemia. Each dried gallstone specimen of about 200 micrograms was dissolved in 5 ml of dimethyl sulfoxide/0.15 M HCI/50 mM disodium-EDTA (8:1:1 by volume) at room temperature. Stone dissolution was complete by 30 min as monitored by the A456 and direct observation, and no oxidative products of bilirubin were observed in the visible spectrum, 350 to 750 nm. By high-performance liquid chromatography, the intact tetrapyrroles were separated as diconjugated and monoconjugated bilirubins; unconjugated bilirubin was resolved as XIII, IX and III alpha-isomers. The isocratic solvent system used was 0.1 M di-n-dodecylamine acetate/0.1 M di-n-octylamine acetate (4:1, v/v) in methanol, pH 7.4, at a flow of 1 ml per min. Diconjugated bilirubin accounted for 6.0 +/- 2.4 molar % (mean +/- S.E.), monoconjugated bilirubin for 37.4 +/- 8.4% and unconjugated bilirubin for 56.3 +/- 8.9% of the solubilized pigments. The IX alpha-isomer represented 96 +/- 1.9% of the unconjugated bilirubin. The presence of bilirubin conjugates in gallstones was confirmed by ethylanthranilate diazotization: the conjugated azodipyrrole in stone had the same retention time as that of conjugated azodipyrrole from rat and mouse bile. A majority of the bilirubin conjugates was sensitive to beta-glucuronidase of liver origin, indicating that the C-1 glucuronide ester was present.(ABSTRACT TRUNCATED AT 250 WORDS)

Biliary lipid excretion in patients with pigment gallstones. A comparison with cholesterol gallstone patients.

Pigment gallstone patients are believed to have normal biliary lipid excretion. In order to measure this and to better understand cholesterol gallstone formation, the kinetics of biliary lipid excretion were studied in three patients who had been cholecystectomized for pigment gallstones and the results compared to those previously obtained in patients cholecystectomized for cholesterol gallstone. Pigment-stone patients had hyperbolic relationships between cholesterol and phospholipid outputs and bile salt output which were similar to those seen in cholesterol-stone patients. However, pigment-stone patients excreted more cholesterol and phospholipid at high bile salt output but approached those levels more gradually than cholesterol-stone patients. As a result, pigment-stone patients produced bile undersaturated with cholesterol at a lower bile salt output than cholesterol-stone patients, and thus they would be less likely to produce supersaturated bile during low bile salt output such as that occurring during an overnight fast. The data suggest that cholesterol-stone patients, in addition to excreting more cholesterol and less bile salts than normals, have a defect in the rate of lipid output in response to decreasing bile salt output.

Noncirrhotic portal hypertension in the adult: case report and review of the literature.

Noncirrhotic portal hypertension results from thrombosis of the extrahepatic portal vein that subsequently is recanalized. Liver function is preserved. In the adult, esophageal variceal hemorrhage is the most common presentation and may occur years after the portal vein thrombosis. We report the case of a 34-year-old man who presented with recurrent esophageal variceal hemorrhage. After ultrasonographic and angiographic evaluation, a diagnosis of idiopathic noncirrhotic portal hypertension was made. Due to recurrent esophageal variceal bleeding, the patient required surgical intervention to control bleeding. The incidence of noncirrhotic portal hypertension is unknown. Multiple etiologies may cause the disorder, although nearly half are idiopathic. The pathogenesis, clinical manifestations, diagnostic evaluation, natural history, prognosis, and management of noncirrhotic portal hypertension are discussed. Endoscopic management of esophageal variceal bleeding is the preferred therapy. However, when endoscopic treatment fails to control variceal hemorrhage, a distal splenorenal shunt is likely to be the most successful operation.

Palliation of esophageal cancer with a self-expanding, silicone-covered stent and a technique for stent retrieval.

Most patients with carcinoma of the esophagus present with progressive, unrelenting dysphagia, malnutrition, and weight loss. Palliation is the primary treatment, since these patients are not candidates for curative surgical resection. Surgery, radiotherapy, and endoscopic modalities have been used for palliation. Recently, self-expanding, metallic stents have been used with considerable success. This type of stent can dislodge into the stomach during or after deployment. We report an approach to retrieve an expandable, silicone-coated stent using a double-channel endoscope, an esophageal dilating balloon, and a polypectomy snare.

Pigment gallstones.

Pigment gallstones are defined as any dark brown-to-black stone, consisting of calcium salts of bilirubin, phosphate, carbonate and other anions, and can be separated into carbonate- and noncarbonate-containing groups. Pigment stones predominate in the rural Orient, in cirrhosis, and in elderly United States patients undergoing cholecystectomy. Clinical associations include bile duct obstruction, stasis, and possibly hemolysis. Of pigment stones, 50% are radioopaque and account for two-thirds of all opaque stones. The concentrations of bile salts, phospholipids,, cholesterol, and total bilirubin in bile are similar to normal levels, but the concentration of unconjugated bilirubin is increased in the bile of some patients. Increased unconjugated bilirubin in bile may be caused by increased hydrolysis of excreted conjugated bilirubin. Unconjugated bilirubin is solubilized by bile salts, but the interaction is primarily nonmicellar. Ionized calcium and pH are important determinants of solubility. Sulfated glycoproteins, excreted in increased amounts in patients with cholelithiasis, may be the site of pigment stone precipitation because these compounds bind calcium salts tightly. E coli is frequently cultured from pigment stones in Japan but not in the United States; thus, bacterial beta-glucuronidase may be important in stone formation in Japan but probably not in the West. Stasis leads to increased calcium secretion and to increases in the concentration of sparingly soluble compounds that may then precipitate. Incomplete emptying of the gallbladder may result in the same concentration process. Unsaturated fats and chronic vagal stimulation cause pigment stone formation in animals. At present, surgery is the only treatment for pigment lithiasis.

Interaction of hemolysis and genotype on ionized calcium in bile of mice with hemolysis-induced gallstones.

In this study, we used an ion-selective membrane electrode to measure ionized calcium in hepatic bile of control +/+ mice and nb/nb mice with hereditary hemolytic anemia. We found that biliary concentrations of ionized, bound, and total calcium were significantly higher (p less than 0.001) and magnesium was significantly lower (p less than 0.001) in nb/nb mice than in control +/+ mice. To separate the hemolytic process from genotypic influences, we transplanted genetically defective bone marrow from nb/nb mice into histocompatible nonhemolytic recipients (W/Wv). After successful engraftment, transplanted W/Wv mice had significantly higher biliary concentrations of ionized calcium than their untreated W/Wv counterparts (p less than 0.001); but bound and total calcium and magnesium concentrations were not different from untreated W/Wv controls. When compared with nb/nb mice, transplanted W/Wv mice had lower ionized calcium (p less than 0.001) and higher bound calcium concentrations (p less than 0.001) in their biles. These data indicate that ionized calcium in hepatic bile is significantly influenced by genotypic factors and subsequently increased in chronic hemolysis; and further, that increased ionized calcium in bile of mice with hemolysis is a risk factor, but of limited predictive value for hemolysis-induced gallstone formation.

Black and brown pigment gallstones differ in microstructure and microcomposition.

The two subtypes of pigment gallstones, black and brown stones, differ in chemical composition and pathogenesis. We examined a black bilirubinate stone and a black phosphate stone (which represented opposite ends of the compositional spectrum of black noncarbonate stones), a black carbonate stone, and a brown pigment stone using scanning electron microscopy and microchemical techniques to determine if stone microstructure and microcomposition reflected different patterns of formation. The cross-sectional surfaces of the black bilirubinate and black phosphate stones were smooth and homogenous. Electron probe microanalysis demonstrated high concentrations of sulfur and copper in the center of the black bilirubinate stone; sulfur was in a low valence state consistent with disulfide linkages in proteins. The brown stone was rough-surfaced with lamellated bands on cross-section. The lighter-colored bands in this stone contained virtually all of the detected calcium palmitate, while the darker sections contained much more calcium bilirubinate. Plasma oxygen etching demonstrated a network of protein interdigitating with calcium bilirubinate salts in the black bilirubinate and black phosphate stones but not in the black carbonate or brown stones. Argon ion etching demonstrated that calcium bilirubinate was in a closely packed rod-shaped arrangement in all three black stones but not in the brown stone. We conclude that the marked differences in structure and composition between the black noncarbonate and brown pigment gallstones support the hypothesis that the two major pigment gallstone types form by different mechanisms. In addition, the layered structures of the black carbonate and brown stones suggest that stone growth is affected by cyclic changes in biliary composition.

Interaction of hemolytic anemia and genotype on hemolysis-induced gallstone formation in mice.

We previously reported that nb/nb mice with hereditary hemolytic anemia spontaneously developed calcium bilirubinate pigment gallstones. To assess the extent to which gallstone formation and bile composition is gene dependent, we transferred the hemolytic process by transplanting bone marrow from nb/nb mice into a nonhemolytic, but histocompatible genotype, W/Wv mice. Hematologic parameters of transplanted W/Wv mice were nearly identical to those of nb/nb mice. Like nb/nb mice, the percentage of transplanted mice with gallstones increased with the duration of the hemolysis and occurred twice as often in female mice as in male mice (37% vs. 19%; p less than 0.05). However, the rate of gallstone formation in transplanted mice was one-third less than that in nb/nb mice (3.6% per month vs. 5.5%; p less than 0.05). Analysis of hepatic bile revealed that (a) marrow-transplanted mice had higher concentrations of unconjugated bilirubin due to hemolysis (p less than 0.05) and of total bile acids determined by the W/Wv genotype (p less than 0.001) than their respective nb/nb counterparts and (b) transplanted mice with stones had a significantly lower proportion of cholic acid (p less than 0.005) and higher proportion of keto-bile acids (p less than 0.005) than transplanted mice without stones, suggesting that the cholic acid concentration may retard stone formation. These data indicate that the hemolytic process is the primary determinant of pigment gallstone formation in these mice and is influenced by the following factors: (a) duration of the hemolytic process, (b) gender, and (c) the genotype that regulates the composition of biliary components like bile acids.