Xenogeneic transplantation of porcine hepatocytes into the CCl4 cirrhotic rat model.

Liver support using extracorporeal devices and hepatocyte transplantation has received renewed interest for the management of acute and chronic liver failure. The aim of this study was to determine whether xenogeneic porcine hepatocytes could integrate into the liver parenchyma of cirrhotic Lewis rats when administered by an intrasplenic route. Cirrhosis was induced by carbon tetrachloride (CCl4) inhalation and confirmed histologically.

A recombinant bovine gallbladder mucin polypeptide binds biliary lipids and accelerates cholesterol crystal appearance time.

Background & Aims: Mucin has a central role in the pathogenesis of cholesterol gallstones, in part because of its ability to bind biliary lipids and accelerate cholesterol crystal appearance time. Previous studies have localized these properties to nonglycosylated mucin domains, and we have recently shown that these domains contain a series of 127-amino acid, cysteine-rich repeats. The aim of this study was to express a recombinant mucin polypeptide containing these repeats and investigate its lipid-binding and pronucleating properties.

pH-dependent conformational change of gastric mucin leads to sol-gel transition.

We present dynamic light scattering (DLS) and hydrophobic dye-binding data in an effort to elucidate a molecular mechanism for the ability of gastric mucin to form a gel at low pH, which is crucial to the barrier function of gastric mucus. DLS measurements of dilute mucin solutions were not indicative of intermolecular association, yet there was a steady fall in the measured diffusion coefficient with decreasing pH, suggesting an apparent increase in size. Taken together with the observed rise in depolarized scattering ratio with decreasing pH, these results suggest that gastric mucin undergoes a conformational change from a random coil at pH >/= 4 to an anisotropic, extended conformation at pH < 4.

The amino-terminal sequence of MUC5B contains conserved multifunctional D domains: implications for tissue-specific mucin functions.

The MUC5B mucin gene product is expressed in a wide variety of secretory epithelia including the gallbladder, salivary glands, trachea, and colon. Previous studies by us and others have described the C-terminal region as well as the central tandem repeating domain of this mucin. In an effort to understand the functional role of MUC5B in diverse human tissues, the sequence encoding the N-terminal region of this mucin was determined from the sequences of exons in three overlapping genomic clones.

Liver-derived CTL in hepatitis C virus infection: breadth and specificity of responses in a cohort of persons with chronic infection.

Hepatitis C virus (HCV)-specific CTL have been found within the inflammatory infiltrate of the liver of chronically infected individuals, but the breadth and specificity of the CTL response in relation to viral load are less well characterized. In this study, we analyzed the intrahepatic CTL response in liver biopsy specimens from 44 chronically infected subjects. Liver-infiltrating lymphocytes were expanded polyclonally in bulk cultures, and multiple clones were derived by limiting dilution.

Urinary assays for desmosine and hydroxylysylpyridinoline in the detection of cirrhosis.

Background/aims: Non-invasive markers of liver fibrosis have great potential for both the diagnosis and therapy of liver disease and cirrhosis. The aim of this study was to evaluate the potential of urinary amino acids desmosine (DES) and isodesmosine (IDES) derived from the breakdown of elastin and hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) derived from fibrillar collagen in diagnosing chronic liver disease.

Methods: We studied 48 patients with chronic liver disease who had varying degrees of liver fibrosis, graded 0-6 using a modified Knodell score, and 20 control subjects without liver disease.

Diffusion behavior of lipid vesicles in entangled polymer solutions.

Dynamic light scattering was used to follow the tracer diffusion of phospholipid/cholesterol vesicles in aqueous polyacrylamide solutions and compared with the diffusive behavior of polystyrene (PS) latex spheres of comparable diameters. Over the range of the matrix concentration examined (Cp = 0.1-10 mg/ml), the diffusivities of the PS spheres and the large multilamellar vesicles exhibited the Stokes-Einstein (SE) relation, while the diffusivity of the unilamellar vesicles did not follow the increase of the solution's viscosity caused by the presence of the matrix molecules.

Molecular cloning of a major human gall bladder mucin: complete C-terminal sequence and genomic organization of MUC5B.

Gall bladder mucin has been shown to play a central role in the pathogenesis of cholesterol gallstone disease. While cloning and sequencing studies have provided a wealth of information on the structure of other gastrointestinal and respiratory mucins, nothing is known about the primary structure of human gall bladder mucin. In this study, we show that the tracheobronchial mucin MUC5B is a major mucin gene product expressed in the gall bladder.

Nitric oxide and gallbladder motility in prairie dogs.

In this study we evaluated the role of nitric oxide (NO) on gallbladder motility in the normal prairie dog by 1) immunohistochemistry, 2) an enzymatic assay for NO synthase (NOS), and 3) an in vivo model to measure whole gallbladder tone and contractility. NOS was localized to gallbladder mucosal cells by NADPH-diaphorase and polyclonal antibodies to a constitutive brain NOS. Gallbladder mucosal homogenates demonstrated total NOS activity in the range of 578 +/- 115 pmol x mg protein(-1) x 30 min(-1).

The acute and long-term effect of balloon sphincteroplasty on papillary structure in pigs.

Background: Balloon dilation or sphincteroplasty is emerging as a potentially safe and effective alternative to sphincterotomy in the management of bile duct stones. However, concerns related to the possible development of fibrosis or papillary stenosis led us to investigate the acute and long-term effects of balloon sphincteroplasty on papillary structure.

Methods: Sixteen pigs (45 to 50 kg) underwent transduodenal cannulation of the bile duct while under general anesthesia.

Feasibility of high-volume screening sigmoidoscopy using a flexible fiberoptic endoscope and a disposable sheath system.

Objectives: Sigmoidoscopy is an effective screening test for colorectal cancer but has yet to have a major impact on mortality because, in part, of inadequate utilization by physicians. To address concerns of inefficient use of time and resources, we examined the feasibility of high volume, single-day flexible sigmoidoscopy (FS) screening sessions using an innovative fiberoptic sigmoidoscope with a disposable sheath system.

Methods: All City of Boston employees over the age of 50 yr (n = 6137) were invited by mail to undergo a screening FS at Boston City Hospital (BCH).

The pronase resistance of cholesterol-nucleating glycoproteins in human bile.

Background & Aims: Many putative pronucleating proteins have been isolated from the biliary concanavalin A (con A)-binding fraction. The pronase resistance of the overall nucleating-promoting activity was almost never taken into consideration. The aim of this study was to identify the major pronase-resistant con A-binding glycoproteins.

HLA class I-restricted cytotoxic T lymphocytes specific for hepatitis C virus. Identification of multiple epitopes and characterization of patterns of cytokine release.

Cytotoxic T lymphocytes (CTL) are important to the control of viral replication and their presence may be important to disease outcome. An understanding of the spectrum of proteins recognized by hepatitis C virus (HCV)-specific CTL and the functional properties of these cells is an important step in understanding the disease process and the mechanisms of persistent infection, which occurs in the majority of HCV-infected individuals. In this report we identify HCV-specific CTL responses restricted by the HLA class I molecules A2, A3, A11, A23, B7, B8, and B53.

Interaction of bovine gallbladder mucin and calcium-binding protein: effects on calcium phosphate precipitation.

Background & Aims: Gallstones consist of calcium salts and cholesterol crystals, arrayed on a matrix of gallbladder mucin (GBM), and regulatory proteins like calcium-binding protein (CBP). To determine if interactions between CBP and GBM follow a biomineralization scheme, their mutual binding and effects on CaHPO4 precipitation were studied.

Methods: Binding of CBP to GBM was assessed by inhibition of the fluorescence of the complex of GBM with bis-1,8-anilinonaphthalene sulfonic acid (bis-ANS).

Mucin-vesicle interactions in model bile: evidence for vesicle aggregation and fusion before cholesterol crystal formation.

Nucleation of cholesterol monohydrate crystals from bile is a critical step in the formation of cholesterol gallstones. Measurement of nucleation in model bile system and the characteristics of the initial nucleus have proven elusive. In this study we have used three separate physical chemical techniques to examine vesicle aggregation and fusion, including dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescent biochemical assays.

Bovine gall-bladder mucin contains two distinct tandem repeating sequences: evidence for scavenger receptor cysteine-rich repeats.

Gall-bladder mucin is a densely glycosylated macromolecule which is the primary secretory product of the gall-bladder epithelium. It has been shown to bind cholesterol and other biliary lipids and to promote cholesterol crystal nucleation in vitro. In order to understand the molecular basis for mucin-lipid interactions, bovine gall-bladder mucin cDNAs were identified by expression cloning and were isolated and sequenced.

Identification of a 130-kilodalton human biliary concanavalin A binding protein as aminopeptidase N.

Background/aims: Human gallbladder bile contains a group of nonmucin glycoproteins that binds to the lectin concanavalin A (con A) and has been reported to promote cholesterol monohydrate crystal nucleation, an event preceding the formation of gallstones. Several of these proteins, including a 130-kilodalton protein, have been isolated and shown to promote nucleation in vitro. The aim of this study was to identify this and other major biliary con A binding glycoproteins.

Hepatitis C virus (HCV)-specific cytotoxic T lymphocytes recognize epitopes in the core and envelope proteins of HCV.

Hepatitis C virus (HCV) is a major cause of posttransfusion and community-acquired hepatitis, and a majority of individuals infected with this virus will subsequently develop chronic hepatitis. Characterization of the host immune response to this infection is an important first step that should facilitate the development of immunomodulatory agents and vaccines. Cellular immune responses, especially those mediated by cytotoxic T lymphocytes (CTL), are important in the control of many viral diseases.

Bovine gallbladder mucin accelerates cholesterol monohydrate crystal growth in model bile.

Background: Gallbladder mucin accelerates cholesterol crystal nucleation, an early step in the pathogenesis of gallstones. To examine the role of gallbladder mucin in postnucleation gallstone maturation, the influence of mucin on cholesterol monohydrate crystal growth was studied in a novel model system.

Methods: Cholesterol crystals of a uniform size were incubated in model biles at 37 degrees C with varying cholesterol saturation indices.

Squamous metaplasia of extrahepatic biliary system in an AIDS patient with cryptosporidia and cholangitis.

AIDS-related cholangiopathy is an increasingly recognized syndrome associated with significant morbidity and mortality. The mechanism of cholangiopathy is unknown but is assumed to be related to infectious pathogens such as CMV and cryptosporidia. The case of a Haitian with HIV and long-standing intestinal cryptosporidiosis who presented with cholangitis and protuberant intrabiliary filling defects is reported.

Cholesterol cholelithiasis in the prairie dog: role of mucin and nonmucin glycoproteins.

The aims of this study were to examine the effect of exogenous prostaglandin on mucin secretion and to determine the role of nonmucin glycoproteins on gallstone formation in the prairie dog model of cholesterol cholelithiasis. The concentration of total glycoprotein and nonmucin glycoproteins was measured in gallbladder bile from four groups of prairie dogs fed a control diet or a diet supplemented with 1.2% cholesterol with or without simultaneous subcutaneous administration of prostaglandin E1.

Postprandial changes in portal haemodynamics in patients with cirrhosis.

Previous studies have shown that portal venous pressure increases in patients with cirrhosis after a protein meal. Since this increase may be mediated by an increase in hepatic blood flow or postsinusoidal hepatic vascular resistance, the present study was designed to examine the precise relation between the postprandial changes in these three variables in patients with cirrhosis and portal hypertension. Estimated hepatic blood flow (EHBF; indocyanine green clearance), portosystemic gradient (PSG; wedged free hepatic venous pressure), and postsinusoidal hepatic vascular resistance (PSR = PSG/EHBF) were measured simultaneously before and at 10 minute intervals after a high protein meal, containing 80 g protein, 40 g carbohydrate and 12 g fat (600 kcal) in nine patients (seven alcoholic, two non-alcoholic) with cirrhosis and portal hypertension.

Controlled trial of antimycobacterial therapy in Crohn's disease. Clofazimine versus placebo.

In order to study the effect of clofazimine, a powerful antimycobacterial and antiinflammatory agent, 49 patients with active Crohn's disease were randomized to either corticosteroids plus clofazimine 100 mg daily (N = 25) or to steroids and matching placebo (N = 24). A total of 28 patients (58%) went into disease remission (clofazimine 16, placebo 12; P = NS) with a fall in disease activity score from 10.5 +/- 4.

Characterization of bovine gallbladder mucin. Amino acid sequences of tryptic peptides from the glycosylated domain of the protein core.

Gallbladder mucin is a densely glycosylated macro-molecule that promotes cholesterol gallstone formation in experimental animals and in humans. Bovine gallbladder mucin structure was studied after chemical deglycosylation by treatment with anhydrous hydrogen fluoride at 23 degrees C for 3 hours. Deglycosylated mucin contained less than 5% of the amino sugar and neutral hexose content of native mucin.