bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolism and Effect of 7–Oxo–Lithocholic Acid 3–Sulfate on Bile Flow and Biliary Lipid Secretion in Rats
Authors: Yamashita Hiroyuki , Setchell Kenneth D.R.
Published: March 2007

Significant amounts of oxo and sulfated bile acids are excreted in the urine of patients with cholestatic liver diseases, but these bile acid species are found only in traces in bile. Several possible explanations for this finding include poor canalicular secretion, rapid biotransformation by oxidoreduction and extrahepatic sulfation of oxo bile acids. To assess the physiological actions and hepatic metabolism of oxo and sulfated bile acids, we synthesized 7–oxo–lithocholic acid 3–sulfate, examined the effect of intravenous infusion of this bile acid (5.0 μmol/min/kg body wt) on bile flow and biliary lipid secretion in Sprague–Dawley rats with a bile fistula and compared this effect with that of the unconjugated analog, 7–oxo–lithocholic acid, and the primary bile acid conjugate, chenodeoxycholic acid 3–sulfate. Bile flow and bile acid secretion increased immediately after infusion of all three bile acids. The highly polar 7–oxo–lithocholic acid 3–sulfate significantly reduced the biliary secretion of phospholipids (p < 0.05) and cholesterol (p < 0.05), but by contrast the more hydrophobic analog, 7–oxo–lithocholic acid, caused a significant increase in the biliary phospholipids (p < 0.01) and cholesterol (p < 0.01) secretion. Infusion of chenodeoxycholic acid 3–sulfate also resulted in an increase in secretion of biliary cholesterol and phospholipids, but the magnitude of the change was less than that induced by 7–oxo–lithocholic acid infusion. Biliary lipid secretion was inversely related to the polarity of the infused bile acid. Negative ion fast atom bombardment—mass spectrometry and gas chromatography—mass spectrometry analyses indicated that the major bile acids excreted in the bile after infusion of 7–oxo–lithocholic acid were taurine and glycine conjugates of the parent compound and the corresponding conjugates of its metabolite, ursodeoxycholate, whereas chenodeoxycholate and its conjugates were minor metabolites. By contrast, 7–oxo–lithocholic acid 3–sulfate and chenodeoxycholic acid 3–sulfate were only partially amidated with taurine and glycine and did not undergo further metabolic transformation of the steroid nucleus. These data demonstrate that sulfation of 7–oxo–lithocholic acid significantly alters its physiological properties and hinders biotransformation, including oxidoreduction, hydroxylation and amidation. The findings that the sulfate conjugates of 7–oxo–lithocholic acid and chenodeoxycholic acid are efficiently and preferentially secreted into bile, and not into urine, would strongly indicate that the bile acid sulfates, found in relatively high proportions in the urine of patients with cholestasis, are of extrahepatic and most probably of renal origin.
Changes in Distribution and Activity of Glutamine Synthetase in Carbon Tetrachloride–Induced Cirrhosis in the Rat: Potential Role in Hyperammonemia
Authors: Gebhardt Rolf , Reichen Jürg
Published: March 2007

Cirrhosis induced in rats by carbon tetrachloride was used to study alterations in the activities and lobular distribution of carbamoylphosphate synthetase and glutamine synthetase. Specific activity of carbamoylphosphate synthetase in cirrhotic subjects was decreased to 70% of controls. Staining was homogeneous within micronodular areas, but varied from area to area and generally showed a decreased intensity. Specific activity of glutamine synthetase and the size of the glutamine synthetase–positive area were decreased to 20% and less of controls. Glutamine synthetase–positive hepatocytes were rare and scattered at the periphery of nodular areas and within fibrous septa, the normal association with the central veins being widely lost. Rarely, complete micronodules showed a slight homogeneous staining for glutamine synthetase. Arginase activity was not affected, whereas glutaminase activity was enhanced by 50%. Serum levels of ammonia were elevated more than 2–fold and those of glutamine by 30%. In contrast, urea levels tended to be slightly diminished. Serum ammonia levels showed a clear negative correlation with the specific activity of glutamine synthetase and the size of the glutamine synthetase–positive area. Furthermore, blood urea levels correlated with the sum of ammonia and glutamine concentrations, but not with each of these substrate concentrations alone. These data suggest that the changes in activity and distribution of glutamine synthetase contribute to hyperammonemia in cirrhosis. Despite a reduced activity of the initial enzyme of the urea cycle, urea synthesis is not diminished accordingly. This may be due to an enhanced flux caused by the elevated blood level of ammonia and an increased hydrolysis of glutamine, because of higher levels of glutaminase. (Hepatology 1994;20:684-691).
Papaverine Inhibits Bile Acid Excretion in Isolated Perfused Rat Liver
Authors: Kumai Tomoyuki , Hoshino Makoto , Hayakawa Tomihiro , Higashi Katsuyoshi
Published: March 2007

We investigated the effects of papaverine on bile acid excretion into bile in the presence of infusions of taurocholic acid, tauroursodeoxycholic acid, taurochenodeoxycholic acid and taurodehydrocholic acid in a single–pass, isolated perfused rat liver model. Although continuous infusion of papaverine (1.6 μmol/min) did not reduce bile acid excretion in the presence of low–dose (1.0 μmol/min) infusions of taurocholic acid or tauroursodeoxycholic acid, papaverine significantly inhibited biliary excretion of bile acids in the presence of low–dose taurochenodeoxycholic acid (–50%) and high–dose (3.0 μmol/min) taurocholic acid (–54%), tauroursodeoxycholic acid (–37%) and taurodehydrocholic acid (–31%). During continuous infusion of taurocholic acid (3 μmol/min), a 15–min infusion of papaverine (3.2 μmol/min) reduced bile acid excretion significantly; however, total uptake of bile acid was slightly decreased by the papaverine infusion. Bile acid excretion increased over the baseline value after the papaverine infusion was stopped and then returned to baseline. These results suggest that papaverine does not affect the uptake phase of bile acids at the sinusoidal membrane but may affect the intracellular transport phase or the excretory phase at the bile canalicular membrane. When taurocholic acid was infused at a constant rate of 3 μmol/min for 20 min without papaverine and then stopped, bile acid excretion decreased gradually and was nearly zero by 52 min. Cumulative bile acid excretion in the 52 min after the end of the infusion reached 3.3 ± 0.2 μmol/gm liver and represented the storage capacity of the liver. When taurocholic acid was coinfused with papaverine at a constant rate of 3.0 μmol/min for 20 min and both infusions were stopped simultaneously, storage capacity of the liver increased significantly, from 3.3 ± 0.2 to 4.0 ± 0.2 μmol/gm liver. Taurocholic acid coinfused with papaverine at a constant rate of 3.0 μmol/min for 20 min. Then taurocholic acid infusion was stopped while the papaverine infusion was continued throughout the experiment. In this experiment, the storage capacity of the liver was reduced significantly, from 3.3 ± 0.2 to 2.2 ± 0.3 μmol/gm liver. and it was revealed that papaverine reduced vasopressin–induced increase in cytosolic Ca2+ with isolated hepatocytes. Our results show that papaverine inhibited the biliary excretion of bile acids without affecting the uptake phase of bile acid and suggest that the microtubule–dependent vesicle pathway may play an important role in intracellular transport during the administration of high–dose or hydrophobic bile acids. (Hepatology 1994;20:692-699).
Alterations in Hypothalamic μ–Opiate Receptor—Mediated Responses But Not Methionine Enkephalin or Proenkephalin Messenger Rna Levels in Rats With Acute Cholestasis
Authors: Swain Mark G.
Published: March 2007

Endogenous opioids, including methionine enkephalin, have been implicated in the control of adrenocorticotrophic hormone release by acting through mu–opiate receptors in the hypothalamus. Recently, alterations in the central opioid system have been postulated to occur in cholestasis. In addition, alterations in hypothalamic corticotropin–releasing hormone content and messenger RNA levels, as well as basal release, have been described in bile duct—resected rats, and hypothalamic methionine enkephalin is colocalized with corticotropin–releasing hormone in hypothalamic neurons. Therefore hypothalamic and pituitary methionine enkephalin content and hypothalamic proenkephalin messenger RNA levels, as well as hypothalamic mu–opiate receptor–mediated responses

in vitro

and

in vivo

, were studied in rats with acute cholestasis caused by bile duct resection and in respective controls. Hypothalamic and pituitary methionine enkephalin levels were similar in bile duct—resected, sham–resected and unoperated control rats. In addition, hypothalamic proenkephalin steady state messenger RNA levels were similar in the three groups of animals. μ–Opiate receptor stimulation of hypothalamic explants

in vitro

with the specific μ–opiate receptor agonist ligand [D–Ala2,N–Me–Phe4, Gly–ol]–Enkephalin resulted in 8.2% and 16.9% inhibition of corticotropin–releasing hormone release in sham–resected and unoperated control rats, respectively. In contrast, treatment of hypothalamic explants from bile duct—resected rats with [D–Ala2, N–Me–Phe4, Gly–ol]–Enkephalin resulted in a significant 22.5% increase in corticotropin–releasing hormone release. Systemic administration of the μ–opiate receptor agonist morphine to rats

in vivo

resulted in significantly higher incremental rises in plasma adrenocorticotropic hormone levels in sham–resected and unoperated control animals than in bile duct—resected rats. Therefore acute cholestasis in the rat is associated with altered hypothalamic mu–opiate receptor–mediated responses but not with alterations in hypothalamic methionine enkephalin or proenkephalin messenger RNA levels. These results suggest novel central roles for opioid peptides in cholestasis. (Hepatology 1994;20:700-705).
Protein Synthesis in the Developing Rat Liver: Participation of Initiation Factors Eif–2 and Eif–2B
Authors: García Ana M. , Martín Elena M. , Alcázar Alberto , Fando Juan L. , Salinas A. M.
Published: March 2007

We studied the decline in protein synthesis in the developing liver in suckling rats (4 to 10 days) and adult rats (2 mo). The rate of protein synthesis was measured with a cell–free system and compared with the activity of two initiation factors, eukaryotic initiation factor–2 and eukaryotic initiation factor–2B, and with casein kinase II, which phosphorylates both factors

in vitro.

The specific activity of the three parameters decreased in adult rats compared with suckling rats and in parallel to the rate of protein synthesis. Quantification of eukaryotic initiation factor–2 in the ribosomal salt wash and in the postmicrosomal supernatant showed that both the specific activity and the levels of eukaryotic initiation factor–2, are much higher in the ribosomal salt wash fractions than in postmicrosomal supernatants, but no differences were found between the two age groups. The eukaryotic initiation factor–2/ribosome ratio was higher in adult rats than in suckling rats, and this parameter seems to be inversely proportional to the rate of protein synthesis. The phosphorylation state of eukaryotic initiation factor–2α, as determined by isoelectric focusing followed by protein immunoblotting, revealed very low and equal levels of phosphorylation in the two animal groups. The lack of changes in eukaryotic initiation factor–2 levels and phosphorylation status suggests that a decrease in the activity or levels of eukaryotic initiation factor–2B could be responsible for the decrease in eukaryotic initiation factor–2 activity and account for, at least in part, the differences observed in the rates of protein synthesis. (Hepatology 1994;20:706-713).
Putrescine As A Comitogen of Epidermal Growth Factor in Rat Liver Growth
Authors: Nagoshi Sumiko , Fujiwara Kenji
Published: March 2007

Putrescine can stimulate regeneration of the remnant liver after partial hepatectomy in rats when exogenously administered, but its mitogenic action has not been shown in cultured hepatocytes. To find its action site(s) in the regulation of hepatocyte proliferation, we examined its effect on hepatocyte DNA synthesis in relation to mitogenic action of epidermal growth factorin vitroandin vivo. When putrescine was added to the medium of adult rat hepatocytes in primary culture 36 hr after plating, DNA synthesis at 50 hr induced by addition of epidermal growth factor at 24 hr was significantly enhanced. This enhancement disappeared by removal of epidermal growth factor at the time of putrescine addition. Putrescine added to the medium was taken up in a dose–related manner by hepatocytes, irrespective of the presence of epidermal growth factor, whereas 125I–epidermal growth factor binding to hepatocytes was not affected by addition of putrescine. When rats received epidermal growth factor at 2–hr intervals until 10 hr, 5–bromo–2′–deoxyuridine labeled and mitotic hepatocytes were increased in number at 48 hr with increased hepatic DNA content. These increases were not affected by concomitant administration of putrescine until 10 hr, but significantly enhanced by additional administration of putrescine and epidermal growth factor from 20 to 30 hr. We conclude that putrescine may stimulate proliferation of hepatocytes that have entered the G1–phase of the cell cycle as a comitogen of epidermal growth factor, probably through action at the molecular levels to enhance its mitogenic activity. (Hepatology 1994;20:725-730).
Effects of Hemopexin on Heme–Mediated Repression of 5–Aminolevulinate Synthase and Induction of Heme Oxygenase in Cultured Hepatocytes
Authors: Sinclair Peter R. , Bement William J. , Healey John F. , Gorman Nadia , Sinclair Jacqueline F. , Bonkovsky Herbert L. , Liem Heng H. , Muller-Eberhard Ursula
Published: March 2007

The serum protein hemopexin is considered to have a major role in the mechanism of the uptake of heme by hepatocytes by means of a heme–hemopexin receptor. Therefore, we examined in primary cultures of adult rat and embryonic chick hepatocytes whether the presence of hemopexin would affect the heme–mediated repression of 5–aminolevulinate synthase activity (the rate–limiting enzyme of heme biosynthesis) and the heme–induced increase of heme oxygenase activity (the rate–limiting step of heme degradation). Both of these heme–mediated effects were partly or entirely prevented by the presence of hemopexin. We conclude that homologous hemopexin, at molar concentrations exceeding that of heme, inhibited the uptake of heme into hepatocytes. These results suggest that heme, in amounts sufficient to affect the ratelimiting steps of heme synthesis and degradation, can only enter hepatocytes in primary culture when the binding capacity of hemopexin for heme has been exceeded or altered. (Hepatology 1994;20:741-746).
Vaccination Against Hepatitis C Virus Infection: Miles to Go Before We Sleep
Authors: Liang Jake T. , Anwer Sawkat M.
Published: March 2007

A high incidence of community–acquired hepatitis C virus infection that can lead to the progressive development of chronic active hepatitis, liver cirrhosis, and primary hepatocellular carcinoma occurs throughout the world. A vaccine to control the spread of this agent that represents a major cause of chronic liver disease is therefore needed. Seven chimpanzees (

Pan troglodytes

) have been immunized with both putative envelope glycoproteins [E1 (gp33) and E2 (gp72)] that were copurified from HeLa cells infected with a recombinant vaccinia virus expression vector. Despite the induction of a weak humoral immune response to these viral glycoproteins in experimentally infected chimpanzees, a strong humoral immune response was obtained in all vaccines. The five highest responders showed complete protection against an i.v. challenge with homologous hepatitis C virus 1. The remaining two vaccinees became infected, but both infection and disease may have been ameliorated in comparison with four similarly challenged control chimpanzees, all of which developed acute hepatitis and chronic infections. These results provide considerable encouragement for the eventual control of hepatitis C virus infection by vaccination.
Hepatitis C Virus: From Epidemiology and Molecular Virology to Immunobiology
Authors: Lau Johnson Y.N.
Published: March 2007

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. In this study, liver–infiltrating lymphocytes from persons with chronic HCV hepatitis were examined for evidence of HCV–specific CTL by using target cells infected with recombinant vaccinia viruses expressing the HCV core, E1, E2, and part of the NS2 proteins. Bulk expansion of liver–derived CD8+ lymphocytes resulted in the detection of HCV–specific CTL activity, whereas activity could not be found in CD8+ lymphocytes expanded from peripheral blood. Epitopes recognized by these CTL were defined by using CTL clones obtained by limiting dilution and target cells sensitized with synthetic HCV peptides. Four distinct HLA class I–restricted epitopes were identified, including two epitopes in the amino–terminal portion of the core protein. These studies provide evidence that the highly conserved core protein is a target for HCV–specific CTL and identify CTL epitopes within the more highly variable E2 envelope protein. Our studies also suggest that HCV–specific CTL are localized at the site of tissue injury in infected persons with chronic hepatitis. Identification of the epitopes recognized by HCV–specific CTL will facilitate exploration of their role in disease pathogenesis and may provide information useful in development of therapeutic interventions or vaccines.
Serum Type Iii Procollagen Peptide, Type Iv Collagen 7S Domain, Central Triple–Helix of Type Iv Collagen and Tissue Inhibitor of Metalloproteinases in Patients With Chronic Viral Liver Disease: Relationship to Liver Histology
Authors: Murawaki Yoshikazu , Ikuta Yujiro , Koda Masahiko , Kawasaki Hironaka
Published: March 2007

To assess the clinical value of serum biochemical markers, the aminoterminal peptide of type III procollagen, type IV collagen 7S domain, the central triplehelix of type IV collagen and tissue inhibitor of metalloproteinases, as a marker of hepatic fibrosis, we measured these four serum markers in 132 patients with chronic viral liver disease and compared these serum markers with liver histological findings. Serum levels of these markers increased closely with the progress of liver disease, and the abnormal percentages of type III procollagen peptide, type IV collagen 7S domain, central triple–helix of type IV collagen and tissue inhibitor of metalloproteinases in patients with cirrhosis were 97%, 95%, 83% and 48%, respectively. These four serum markers strongly correlated with the histological degree of periportal with or without bridging hepatocellular necrosis and of liver fibrosis and correlated weakly with the degree of intralobular degeneration and focal necrosis and the degree of portal inflammation. The correlation coefficients of serum type IV collagen 7S domain with periportal with or without bridging hepatocellular necrosis and with liver fibrosis were the highest among these four serum markers, suggesting that serum type IV collagen 7S domain is the most valuable diagnostic marker to assess the degree of liver fibrosis in chronic viral liver disease. When we assessed the ability of each serum marker to detect cirrhosis with a receiver operating curve, the best test was type IV collagen 7S domain, and the second best was type III procollagen peptide. For the detection of cirrhosis, serum type IV collagen 7S domain concentration was 79% sensitive and 82% specific at a cutoff value of 8.5 ng/ml, and serum type III procollagen peptide concentration was 76% sensitive and 71% specific at a cutoff value of 1.1 U/ml. Serum central triple–helix of type IV collagen and tissue inhibitor of metalloproteinases concentrations were less accurate for the detection of cirrhosis than the other two tests. the combination of type IV collagen 7S domain and type III procollagen peptide tests had 88% sensitivity. These data suggested that the type IV collagen 7S domain test or the combination of type IV collagen 7S domain and type III procollagen peptide tests could be useful for diagnosing cirrhosis in patients with chronic viral liver disease. (Hepatology 1994;20:780-787).
Induction of Apoptosis in the Murine Liver With Recombinant Human Activin A
Authors: Hully James R. , Chang Ling , Schwall Ralph H. , Widmer Ramon H. , Terrell Timothy G. , Gillett Nancy A.
Published: March 2007

Recombinant human activin A, a member of the transforming growth factor–β superfamily, induced significant cell loss in rodent livers and in primary hepatocyte cultures. Histologically and biochemically the hepatocyte death was mediated by apoptosis, a form of programmed cell death. Male mice were treated with 200 or 500 μg recombinant human activin A/kg body wt/day for up to 3 days by means of a subcutaneously implanted minipump. Livers were taken for light and electron microscopy, DNA isolation and

in situ

nick end–labeling. Primary cultures of rat hepatocytes were treated with 10 ng/ml recombinant human activin A for 24 hr before being harvested for electron microscopy and DNA isolation. Infusion of activin A evoked dose–dependent loss of liver mass due to the atrophy and death of hepatocytes around the central vein. Morphologically, the dying cells demonstrated all the characteristic nuclear and cytoplasmic features of apoptosis. Low molecular weight DNA isolated activin A—treated intact livers and primary cultures exhibited the typical oligosomal ladder. Nick end–labeling of DNA

in situ

confirmed that virtually all topographical apoptotic hepatocytes had fragmented DNA. The currently accepted criteria for apoptosis (i.e., specific morphological alterations and internucleosomal clipping of DNA) were evident in activin A—treated hepatocytes both

in vitro

and

in vivo

, leading to the conclusion that cell loss occurs mainly through apoptosis. These observations suggest that activin A may be important in hepatic homeostasis. (Hepatology 1994;20:854-861).
Renal Response to A Saline Load in Well–Compensated Alcoholic Cirrhosis
Authors: Wong Florence , Massie Denise , Hsu Paul , Dudley Francis
Published: March 2007

A total of 29 patients with well–compensated alcoholic cirrhosis and 9 healthy control subjects of similar age and sex were studied to assess their response to a challenge of 2 L of normal saline infused over a 1 hr period. Patients with cirrhosis had an adequate effective arterial blood volume in the basal state as assessed by neurohumoral markers of vascular filling. They also had a lower renal vascular resistance (p = 0.048) and a higher glomerular filtration rate (p = 0.014) than the controls, indicating the presence of renal vasodilation. Both groups were in sodium balance, but the patients with cirrhosis had a higher filtered load of sodium, an increased proximal tubular reabsorption of sodium (p = 0.015) and a decreased fractional excretion of sodium (p < 0.001). The administration of a saline load was not accompanied by any significant changes in the renal circulation in the patients with cirrhosis. They were unable to suppress their proximal tubular reabsorption of sodium to the same extent as the controls (p = 0.012), so by the fourth hour a significant difference in the rate of urinary excretion of sodium was evident. In the patients with cirrhosis, glomerular filtration rate before and after the saline load correlated significantly with indocyanine green extraction (r = 0.65; p = 0.002), whereas the tubular handling of sodium was dependent on antipyrine clearance (r = 0.80; p < 0.001). The results indicate that in well–compensated alcoholic cirrhosis, abnormalities in the renal circulation and tubular handling of sodium occur before evidence exists of a decreased effective arterial blood volume and are independent, with the renal vasodilatation being related to the extent of intrahepatic shunting, whereas impaired renal tubular sodium handling is dependent on hepatic function. These results are consistent with the hypothesis that, in cirrhosis, activation of neurohumoral pressor systems is not solely responsible for the changes in sodium homeostasis that predispose to the development of ascites. (Hepatology 1994;20:873-881).
Human Combinatorial Autoantibodies and Mouse Monoclonal Antibodies to Pdc–E2 Produce Abnormal Apical Staining of Salivary Glands in Patients With Coexistent Primary Biliary Cirrhosis and Sjogren's Syndrome
Authors: Tsuneyama Koichi , Van De Water Judy , Nakanuma Yasuni , Cha Sanghoon , Ansari Aftab , Coppel Ross , Gershwin Eric M.
Published: March 2007

An increase in the incidence of Sjögren's syndrome in patients with primary biliary cirrhosis has been noted. Indeed, primary biliary cirrhosis has been described as a ductal disease with involvement not only of the biliary tract but of epithelial ductal cells in other organs. We have previously reported the development of a panel of mouse monoclonal antibodies directed at PDC–E2, the major autoantigen of primary biliary cirrhosis. One such antibody, C356.1, but none of the other monoclonal antibodies, reacted not only with mitochondria but also with the apical region of biliary epithelium of patients with primary biliary cirrhosis but notion similar specimens from patients with other liver disease or normal human liver. In addition, we have reported the development of human combinatorial antibodies specific for PDC–E2; these reagents also reacted uniquely with the biliary epithelium of patients with primary biliary cirrhosis. In this paper, we have performed a similar study and have compared the staining of monoclonal antibody C355.1 and a human combinatorial antibody, SP4, with control monoclonal antibodies with respect to their reactivity of salivary glands in 9 patients with primary biliary cirrhosis associated with Sjögren's syndrome, 11 patients with Sjögren's syndrome alone and 7 control patients. Interestingly, the apical region of the salivary gland epithelial cells of approximately 50% of patients with coexisting primary biliary cirrhosis and Sjögren's syndrome had a stainingpattern similar to that seen in primary biliary cirrhosis biliary epithelium. In contrast, we did not observe this reactivity in any patient with Sjögren's syndrome alone or in any control patient. These data suggest that similar mechanisms may explain the abnormal expression pattern of PDC–E2 or a cross–reacting molecule in the ductal tissue of patients with primary biliary cirrhosis. (HEPATOLOGY 1994;20:893-898).
Evaluation of Hepatocellular Function by Way of Receptor–Mediated Uptake of A Technetium–99M—Labeled Asialoglycoprotein Analog
Authors: Pimstone Neville R. , Stadalnik Robert C. , Vera David R. , Hutak Dusan P. , Trudeau Walter L.
Published: March 2007

We have developed a quantitative functional imaging study of the liver using a radiolabeled asialoglycoprotein analog, Tc–galactosyl–neoglycoalbumin. Heart and liver time–activity data can be transformed by automated kinetic analysis into asialoglycoprotein hepatocyte receptor concentration. Twenty–eight healthy controls, 46 patients with noncholestatic chronic liver injury and 11 patients with primary biliary cirrhosis were studied. Liver function was also assessed by Pugh modified–Child–Turcotte criteria, 14C–aminopyrine breath test and indocyanine green clearance (24 patients). Results: (a) In normal controls with a Child–Turcotte criteria score of 5, receptor concentration ranged from 0.63 to 1.19 μmol/L, with a mean 0.83 ± 2 S.D. 0.06 μmol/L, which was significantly higher (p < 0.001) than that of the patient group (mean receptor concentration = 0.44 ± 2 S.D. 0.04 μmol/L). In cirrhotic patients with Child–Turcotte criteria score of 5, the mean receptor concentration was 0.60 ± 2 S.D. 0.07 μmol/L, which was significantly lower than controls (p < 0.01). In end–stage cirrhosis (Child–Turcotte criteria score 11 to 15), a group in which patients died or required orthotopic liver transplantation within 1 yr, the mean receptor concentration was 0.35 ± 2 S.D. to 0.07 μmol/L. The sensitivity and specificity for receptor concentration in relation to liver disease, with values above 0.65 μmol/L being normal, were 0.96 and 0.88, respectively. Receptor concentration correlated well with Child–Turcotte criteria score (r = 0.78, p = <0.001), with aminopyrine breath test (r = 0.75, p = <0.001) and with indocyanine green clearance (r = 0.88, p = <0.001). (b) Among 11 primary biliary cirrhosis patients, ten had Child–Turcotte criteria score of 5. Receptor concentration and aminopyrine breath test values were lower in primary biliary cirrhosis patients with liver biopsy histological stage III–IV than I–II, although the numbers were too small for statistical analysis. We conclude that determination of receptor concentration, a rapid and bilirubin–independent method of quantitating hepatocellular function, correlates well with Child–Turcotte criteria score, aminopyrine breath test and indocyanine green clearance. This could prove valuable in evaluating the extent and the progression of liver disease and the impact of newer therapies in retarding chronic cholestatic and viral liver injury. Long–term studies are needed to confirm this speculation. (Hepatology 1994;20:917-923).
The Mutant Eisai Hyperbilirubinemic Rat Is Resistant to Bile Acid-Induced Cholestasis and Cytotoxicity
Authors: Hoshino Makoto , Hayakawa Tomihiro , Hirano Asamitsu , Kamiya Yasutaka , Ohiwa Takayuki , Tanaka Akitaka , Kumai Tomoyuki , Inagaki Takanori , Miyaji Makoto , Takeuchi Toshihiko
Published: March 2007

We investigated bile flow and biliary excretion of bile acids in the Eisai hyperbilirubinemic rat, a Sprague–Dawley mutant rat with conjugated hyperbilirubinemia, using both

in vivo

and

in vitro

models.

In vivo

bile flow was lower in Eisai hyperbilirubinemic rats than in the control rats before and after taurocholate was infused. After taurocholate was infused, bile acid output was similar in the Eisai hyperbilirubinemic rats and control rats. In the isolated perfused rat liver, biliary excretion of bile acids was higher in the Eisai hyperbilirubinemic rats than in the control rats after a high–dose infusion of taurocholate (0.33 μmol/min/gm liver). Infusion of taurochenodeoxycholate (0.22 μmol/min/gm liver) did not produce cholestasis and did not reduce the biliary excretion of bile acids in the Eisai hyperbilirubinemic rats. Taurochenodeoxycholate significantly increased the phospholipid/bile acid molar ratio and slightly reduced bile acid-induced alkaline phosphatase output into bile. The release of lactate dehydrogenase from the perfused liver 30 min after the start of the taurochenodeoxycholate infusion was 10 times lower in the Eisai hyperbilirubinemic rats than in the control rats (2.0 ± O.8 vs. 28.7 ± 6.8 mU/min/gm liver). When the isolated perfused rat liver was infused with a 1–min pulse of horseradish peroxidase (25 mg), we observed an early and late peak of biliary excretion of horseradish peroxidase. The Eisai hyperbilirubinemic rats showed a significant increase in the late peak. Although taurochenodeoxycholate produced dose–dependent increases in lactate dehydrogenase levels in the medium at 3 hr in primary cultured hepatocytes from both strains, the increase was significantly smaller in the Eisai hyperbilirubinemic rat. The intracellular content of taurochenodeoxycholate in the Eisai hyperbilirubinemic rat was 11.7 ± 1.5 nmol/mg protein, half that seen in the control rats. These findings indicate that the Eisai hyperbilirubinemic rat is resistant to bile acid-induced cholestasis and liver injury and that this resistance may be related, in part, to a reduction in the intracellular accumulation of bile acids. This phenomenon might be explained by an increased intrahepatic microtubule–dependent vesicle transport of bile acids in the mutant rats. (Hepatology 1994;20:932-939).
Endogenous Nitric Oxide Attenuates Ethanol–Induced Perturbation of Hepatic Circulation in the Isolated Perfused Rat Liver
Authors: Oshita Masahide , Takei Yoshiyuki , Kawano Sunao , Hijioka Taizo , Masuda Eiji , Goto Moritaka , Nishimura Yoshiya , Nagai Hirotaka , Iio Sadaharu , Tsuji Shingo , Fusamoto Hideyuki , Kamada Takenobu
Published: March 2007

The purpose of this study was to clarify the role of endogenous nitric oxide in ethanol–induced perturbation of microcirculation and hepatic injury in perfused rat liver. Infusion of ethanol into the portal vein at 25 and 100 mmol/L increased portal pressure, which is an indicator of hepatic vasoconstriction, in a concentration–dependent fashion. Portal pressure started to rise immediately after ethanol load, then decreased gradually and remained at higher than basal levels throughout the period of ethanol infusion. Release of lactate dehydrogenase into the effluent perfusate began to increase after 30 min of ethanol infusion and continued to increase during the 60–min period of ethanol infusion. The lactate dehydrogenase level in the effluent perfusate at 60 min was dependent on the ethanol concentration (0 mmol/, 8 ± 3 IU/L 25 mmol/L, 16 ± 2 IU/L 100 mmol/L, 52 ± 6 IU/L). Simultaneous infusion of NG–monomethyl–L–arginine, a nitric oxide synthesis inhibitor, enhanced significantly the ethanol–induced increase in portal pressure by 100% to 400% and increased lactate dehydrogenase release by 40% to 80%. The effect of NG–monomethyl–L–arginine on the ethanol–induced increase in portal pressure was completely reversed by the co–infusion of an excess dose of L–arginine. Change in portal pressure averaged over 60 min of ethanol infusion correlated with levels of lactate dehydrogenase release 60 min after the initiation of ethanol infusion (r = 0.77, p < 0.01). In conclusion, inhibition of the action of endogenous nitric oxide was associated with an increase in hepatic vasoconstriction and hepatocellular damage. These results suggest that endogenous nitric oxide acts as a vasodilator that reduces ethanol–induced vasoconstriction, thus improving microcirculation and leading to decreased hepatic damage. (Hepatology 1994;20:961-965).
Modulation of Hepatic Mrna Levels After Administration of Lipopolysaccharide and Diphtheria and Tetanus Toxoids and Pertussis Vaccine Adsorbed (Dtp Vaccine) to Mice
Authors: Ansher Sherry S. , Thompson Walter
Published: March 2007

Administration of whole–cell diphtheria and tetanus toxoids and pertussis vaccine adsorbed (DTP vaccine) caused marked depression in the expression of mRNA for isozymes of cytochrome P–450 in the livers of endotoxin–responsive and nonresponsive mice. The levels of expression of mRNA for a polycyclic aromatic hydrocarbon-inducible (CYP 1A2) and an ethanol–inducible (CYP2E1) form of P–450 were reduced by 70% to 80% 8 to 12 hr after vaccination or

Bordetella pertussis

endotoxin administration. These effects are preceded by marked increases (threefold to sixfold) in mRNA expression for interleukin–6, interleukin–1 and tumor necrosis factor in both strains of mice, with maximal increases 1 to 2 hr after injection. This is the first demonstration that levels of cytokine mRNA are altered in the liver in response to DTP vaccine administration. The finding of increased cytokine mRNA in the livers of mice injected with vaccine supports a role for cytokines as mediators of the decreased levels of cytochrome P–450. In addition, inducible nitric oxide synthase mRNA expression is also increased after vaccine administration, with a peak at 4 hr. The temporal relationship of the increased cytokine mRNA expression, increased nitric oxide synthase and decreased expression of P–450 mRNAs suggests a mechanism by which cytokines mediate the induction of nitric oxide synthase, which increases nitric oxide and decreases the activities of some cytochromes P–450. (Hepatology 1994;20:984-991).
Hepatic Ito Cells Contain Calcium Channels: Increases With Transforming Growth Factor–β 1
Authors: Oide Hirosumi , Thurman Ronald G.
Published: March 2007

Ito cells (fat–storing cells) have been implicated in mechanisms of liver fibrosis, and transforming growth factor–β1 is a key factor that stimulates collagen production by Ito cells. Moreover, Ito cells are reported to possess contractile proteins and to contract with ligands. We recently reported the presence of L–type voltage–operated Ca2+ channels in Kupffer cells. In this study, we examined whether Ito cells contain Ca2+ channels and also evaluated the effect of transforming growth factor–β1 on Ca2+ channels. Cytosolic free calcium concentration was measured in individual cultured Ito cells with the fluorescent Ca2+ indicator dye fura–2. Partial replacement of extracellular Na+ with K+ caused an increase in cytosolic free calcium, presumably as a result of transmembrane Ca2+ influx. Basal cytosolic free calcium levels were around 40 to 50 nmol/L in both control and transforming growth factor–β1—treated cells. In transforming growth factor–β1—treated cells, cytosolic free calcium increased in response to K+ at values as low as 10 mmol/L, whereas untreated cells did not respond. Half–maximal increases in cytosolic free calcium in transforming growth factor–β1—treated cells were observed with 63 ± 6 mmol/L K+. With 100 mmol/L K+, intracellular free calcium increased around fourfold above basal values in transforming growth factor–β1—treated cells but was only increased about twofold in untreated controls. We conclude that this increase in cytosolic free calcium occurs by way of voltage–operated calcium channels; it did not occur in the absence of extracellular calcium and cannot be explained by Na+/Ca2+ exchange mechanisms. The influx of Ca2+ was only about one third as large on subsequent depolarizations and was not sensitive to the dihydropyridine–type calcium channel agonist BAY K 8644. In contrast, Ca2+ influx was inhibited by the dihydropyridine–type calcium channel blocker nitrendipine. These data indicate that Ito cells contain voltage–operated Ca2+ channels. Furthermore, transforming growth factor–β1 activates or up–regulates these Ca2+ channels.(HEPATOLOGY 1994;20:1009–1014)
Tumor Necrosis Factor–α Regulates In Vivo Nitric Oxide Synthesis and Induces Liver Injury During Endotoxemia
Authors: Harbrecht Brian G. , Silvio Mauricio Di , Demetris A. J. , Simmons Richard L. , Billiar Timothy R.
Published: March 2007

Tumor necrosis factor–alpha is a principal mediator of the pathophysiological effects of endotoxemia and endotoxin shock. Tumor necrosis factor–α also contributes to the stimulation of nitric oxide synthesis by the induction of the enzyme nitric oxide synthase in a variety of tissues. Although the importance of tumor necrosis factor–α in the induction of nitric oxide synthase activity

in vitro

is well known, its role in

in vivo

nitric oxide synthesis has not been convincingly established. We were interested in determining whether tumor necrosis factor–α plays a significant role in the

in vivo

induction of nitric oxide synthesis. In

Corynebacterium parvum

—primed mice, lipopolysaccharide injection resulted in elevated serum tumor necrosis factor–α levels early and increased hepatic enzyme release (641 ± 80 IU AST/L 22.7 ± 1.9 IU ornithine carbamoyltransferase per liter) and plasma nitrite and nitrate (804 ± 84 μmol/L) 5 hr after lipopolysaccharide injection. Polyclonal rabbit anti–mouse anti—tumor necrosis factor–α reduced

in vivo

tumor necrosis factor–α levels (1 hr, 7,332 ± 1,492 U tumor necrosis factor–α per milliliter) and reduced nitric oxide synthesis as measured by plasma nitrite and nitrate (352 ± 69 μmol/L). Polyclonal rabbit anti–mouse anti—tumor necrosis factor–α also reduced lipo–polysaccharide–induced hepatic enzyme release (428 ± 33 IU AST/L 16.0 ± 2.5 IU ornithine carbamoyltransferase per liter). NG–monomethyl–L–arginine, a competitive inhibitor of nitric oxide synthesis, also decreased plasma nitrite and nitrate (104 ± 9 μmol/L) but increased the lipopolysaccharide–induced hepatic injury (797 ± 66 IU AST/L 33.1 ± 2.1 IU ornithine carbamoyltransferase per liter). These results show that tumor necrosis factor–α not only acts as an

in vivo

signal for the induction of nitric oxide synthesis but also acts as a mediator of the lipopolysaccharide–induced hepatic injury. The mechanism by which tumor necrosis factor–α exerts its damaging effect on hepatic cells has not been determined but appears to be independent of its induction of nitric oxide synthesis. (Hepatology 1994;20:1055-1060).
Expanding the Diagnostic Capabilities of Endoscopy: Common Bile Duct Stones. Amouyal P, Amouyal G, Lévy P, Tuzet S, Palazzo L, Vilgrain V, Gayet B, Belghiti J, Fékété F, Bernades P. Diagnosis of Choledocholithiasis by Endoscopic Ultrasonography. Gastroenterology 1994;106:1062-1067
Authors: Brugge William R.
Published: March 2007

ABSTRACT

Background/Aims:

Endoscopic ultrasonography is a promising procedure for the diagnosis of extrahepatic cholestasis. Accuracy for the diagnosis of choledocholithiasis by ultrasonography and computed tomography were prospectively compared with endoscopic ultrasonography in 62 consecutive patients.

Methods:

Final diagnosis was determined by endoscopic retrograde cholangiography with or without sphincterotomy or intraoperative cholangiography with or without choledochoscopy. All of the patients had abdominal ultrasonography, computed tomography, endoscopic ultrasonography, and either an endoscopic retrograde (n = 40) or intraoperative cholangiography (n = 32) performed.

Results:

Choledocholithiasis was confirmed in 22 patients. Thirteen patients had a stone with a diameter < 1 cm, and 14 had a nonenlarged common bile duct. Endoscopic ultrasonography was more sensitive (97%) than ultrasonography (25%; P < 0.0001) and computed tomography (75%; P < 0.02). Specificity and positive predictive value were not significantly different. Negative predictive value of endoscopic ultrasonography (97%) was better than that of ultrasonography (56%; P < 0.0001) and computed tomography (78%; P < 0.02). Results were unchanged after six patients in whom the absence of choledocholithiasis was considered probable after follow–up were excluded. Endoscopic ultrasonography results did not depend on stone diameter or common bile duct dilatation.

Conclusions:

Endoscopic ultrasonography appears to be the best diagnostic tool for the diagnosis of choledocholithiasis compared with other noninvasive procedures.
An Autoantigen in Psc? Whither or Whether? Mandal A, Dasgupta A, Jeffers L, Squillante L, Hyder S, Reddy R, Schiff E, Das Km. Autoantibodies in Sclerosing Cholangitis Against A Shared Peptide in Biliary and Colon Epithelium. Gastroenterology 1994;106:185-192
Authors: Van De Water Judy , Gershwin Eric M.
Published: March 2007

ABSTRACT

Background/Aims:

A strong association exists between ulcerative colitis and primary sclerosing cholangitis (PSC). Previously, the presence of a unique epitope shared by colon and biliary epithelial cells was shown by using the novel monoclonal antibody (MAb) 7E12H12 developed against a colonic epithelial protein. In the present study, the presence of circulating autoantibody in PSC against this peptide was examined.

Methods:

Sera from 16 patients with PSC, 13 with primary biliary cirrhosis, 6 with secondary biliary stricture, and 6 with chronic liver diseases and 10 normal subjects were used. An inhibition immunoperoxidase assay using the 7E2H12 MAb was developed against sections of bile duct and gallbladder. Sera were also examined in an enzyme–linked immunosorbent assay (ELISA) against the gallbladder extract enriched in 7E12H12–reactive protein.

Results:

About two thirds of the sera from patients with PSC blocked the binding of 7E12H12 MAb on the bile duct and gallbladder, whereas non–PSC sera did not. In the ELISA, 93% of PSC sera had circulating immunoglobulin G antibodies against the enriched gallbladder extract. The reactivity of sera from the PSC group was significantly (P < 0.01 to P < 0.0001) higher than in each of the non–PSC groups.

Conclusions:

Sera from patients with PSC contains autoantibodies against a cross–reactive peptide shared by colon and biliary epithelial cells.
Degree of Diversity of Hepatitis C Virus Quasispecies and Progression of Liver Disease
Authors: Honda Masao , Kaneko Shuichi , Sakai Akito , Unoura Masashi , Murakami Seishi , Kobayashi Kenichi
Published: March 2007

We examined the quasispecies of the hepatitis C virus genome in 28 patients with liver disease of varying severity. Nucleotide sequences of the hepatitis C virus genome spanning the region from the core to envelope were used to calculate the nucleotide diversity: 0.58% ± 0.88% in 5 patients with acute hepatitis, 0.85% ± 0.62% in 5 patients with chronic persistent hepatitis, 1.79% ± 0.92% in 11 patients with chronic active hepatitis, 3.05% ± 1.26% in 4 patients with cirrhosis and 2.71% ± 1.47% in 3 patients with cirrhosis complicated by hepatocellular carcinoma. Thus the intrapatient variation in nucleotides increased significantly with severity of liver disease (p < 0.01), except in those cases of cirrhosis complicated by hepatocellular carcinoma. Multivariate analysis including the histology, duration of infection, age, sex, history of blood transfusion and serum level of ALT at diagnosis as variables showed that the histological finding was the strongest independent factor of the nucleotide diversity (p = 0.003). Serial analysis of the genome in three patients demonstrated that the intrapatient variation in nucleotides increased with the progression of liver disease. The magnitude of the intrapatient variation in nucleotides deduced from the observed changes in the patients was correlated with the mean serum levels of ALT. These findings suggest that the degree of diversity of HCV quasispecies is related to the progression of liver disease. (Hepatology 1994;20:1144-1151.