bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative importance of the 25-hydroxylation pathway for bile acid biosynthesis in the rat
Authors: Duane William C. , Björkhem Ingemar , Hamilton Jan Neal , Mueller Susan M.
Published: March 2007

During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. In the present study, we have quantitated the relative importance of these two pathways in vivo by measuring production of [14C]acetone from [14C] -26-cholesterol. Four days after intraperitoneal injection of 20 to 40 μCi [14C]-26-cholesterol and 1 day after beginning a constant intravenous infusion of unlabeled acetone at 25 μmoles per kg per min, 6 male and 2 female Sprague-Dawley rats underwent breath collections. Expired acetone was trapped and purified as the 2,4-dinitrophenylhydrazine derivative. 14CO2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied times the acetone infusion rate to calculate production of [14C]acetone. [14C] Acetone production averaged 1.7% of total release of 14C from [14C]-26-cholesterol, estimated by 14CO2 output. The method was validated by showing that [14C] acetone production from [14C]isopropanol averaged 111% of the [14C]isopropanol infusion rate. We conclude that, in the normal rat, the 25-hydroxylation pathway accounts for less than 2% of bile acid synthesis.
Ethinylestradiol stimulates a biliary cholesterol-phospholipid cosecretion mechanism in the hamster
Authors: Berr Frieder , Stellaard Frans , Goetz Alwin , Hammer Claus , Paumgartner Gustav
Published: March 2007

The mechanism of ethinylestradiol-induced biliary secretion of excess cholesterol, a potential causative factor of cholesterol gallstones, is not yet known. It might be related to altered bile acid metabolism, since the rate of cholesterol and phospholipid secreted into bile is thought to be influenced by the hydrophobicity of the bile acid species secreted. We therefore studied the effect of ethinylestradiol on bile acid metabolism and on secretory relationships between taurocholate and cholesterol/phospholipids in bile. Litter-matched Syrian female hamsters (80 to 100 gm body weight) were injected subcutaneously with either 0.2 ml per day corn oil (controls) or a pharmacologic dose of 5 mg per kg per day ethinylestradiol in corn oil (EE-hamsters; n = 6) for 5 days. On Day 6, bile was collected for 60 min (basal secretory rate) via a bile duct fistula after exclusion of the gallbladder. Then, a graded infusion of taurocholate was given for 110 to 130 min. Secretory rates (nmoles. min−1.−1 liver) for bile acids, cholesterol and phospholipids were determined and their mutual “linkage coefficients” (nmoles of secretory increment per 1 nmole of bile acid secreted) calculated by linear regression analysis. EE-hamsters had higher (p < 0.02) basal secretory rates of cholesterol (0.71 ± 0.21 vs. 0.45 ± 0.10) and phospholipids (5.74 ± 1.04 vs. 4.21 ± 0.73) than controls at comparable bile flow and bile salt secretion rates. Cholic acid pool size and the fractional composition of bile acid species in bile were similar. During graded taurocholate infusion, biliary secretion rates of bile acids were comparable (correlation coefficient = 0.90; p < 0.02) in matched pairs.

EE-hamsters had 60 and 67% higher linkage coefficients for cholesterol/bile acid secretion and phospholipid/bile acid secretion, whereas the linkage coefficient for cholesterol/phospholipid secretion and the y-intercepts of all regressions were not significantly different. In conclusion, ethinylestradiol administration to hamsters increases cholesterol and phospholipid output into bile without increasing the secretion of more hydrophobic bile acids. The unaltered cholesterol/phospholipid linkage suggests that a cholesterol-phospholipid cosecretion mechanism is stimulated.
Patients with deficient ascitic fluid opsonic activity are predisposed to spontaneous bacterial peritonitis
Authors: Runyon Bruce A.
Published: March 2007

To assess the risk of development of spontaneous bacterial peritonitis in relation to ascitic fluid opsonic activity, routine admission abdominal paracentesis was performed on 119 patients during 141 hospitalizations. Paracentesis was repeated if evidence of peritonitis developed during the hospitalization. The ascitic fluid opsonic activity (0.2 ± 0.5 log kill) of 24 spontaneously infected specimens was significantly (p < 0.001) lower than that of the group with sterile portal hypertension-related ascites (0.8 ± 1.1 log kill), and significantly lower than the group with ascites of miscellaneous type (2.4 ± 1.0 log kill, p < 0.001). The C3 and C4 concentrations of the spontaneous peritonitis specimens were also significantly lower than in the specimens from the other groups. Of the 55 patients whose initial sterile ascitic fluid opsonic activity was <0.2 log kill, 8 (14.5%) developed spontaneous bacterial peritonitis during the hospitalization; whereas none of the 70 patients with sterile ascitic fluid opsonic activity ≥0.2 log kill developed spontaneous peritonitis. This difference in the risk of development of peritonitis was significant (p < 0.01). Patients with deficient ascitic fluid opsonic activity are predisposed to spontaneous bacterial peritonitis.
Morphological and hemodynamic changes in the portal venous system after distal splenorenal shunt: An ultrasound and pulsed doppler study
Authors: Bolondi Luigi , Gaiani Stefano , Mazziotti Alighieri , Casanova Paolo , Cavallari Antonino , Gozzetti Giuseppe , Barbara Luigi
Published: March 2007

We investigated a group of patients who underwent distal splenorenal shunt using high-resolution real-time equipment and a duplex scanner with the aims: (i) to evaluate the rate of visualization of shunt; (ii) to assess change in size in the portal vein, and (iii) to characterize the flow pattern in the splenic vein and to study flow direction and velocity in the portal vein, thus adding new data on the efficacy of this operation in maintaining hepatic perfusion. Real-time ultrasonography was performed in 29 patients before surgery, after 7 to 30 days and after 4 to 12 months. Direct visualization of the shunt was achieved in 53.5% of the patients. Mean caliber of the portal vein significantly decreased after the operation: preoperative = 1.52 ± 0.32; after 7 to 30 days = 1.32 ± 0.16 (p < 0.001), and after 4 to 12 months = 0.99 ± 0.19 (p < 0.001). The overall postoperative incidence of portal thrombosis was 22.2%. Thirteen of these patients also underwent a postoperative (4 to 36 months) pulsed Doppler investigation. Flow towards anastomosis was demonstrated in the splenic vein in 11 patients, and in 7 cases, typical caval pulsatility was observed. Decreased hepatopetal flow in the portal vein was found in 10 of 13 patients. In two patients, no flow was detectable and in the other the flow was hepatofu-gal. On the basis of our data, we can affirm that pulsed Doppler investigation may provide useful data for the evaluation of shunt patency and preservation of a decreased portal hepatic perfusion in the majority of patients.
Commentary on meta-analysis in clinical trials
Authors: Berlin Jesse , Chalmers Thomas C.
Published: March 2007

This paper examines eight published reviews each reporting results from several related trials. Each review pools the results from the relevant trials in order to evaluate the efficacy of a certain treatment for a specified medical condition. These reviews lack consistent assessment of homogeneity of treatment effect before pooling. We discuss a random effects approach to combining evidence from a series of experiments comparing two treatments. This approach incorporates the heterogeneity of effects in the analysis of the overall treatment efficacy. The model can be extended to include relevant covariates which would reduce the heterogeneity and allow for more specific therapeutic recommendations. We suggest a simple noniterative procedure for characterizing the distribution of treatment effects in a series of studies.
Dissolution of cholesterol gallstones by perfusion: A solution for the matrix?
Authors: Marks Jay W.
Published: March 2007

The goal of this study was to identify the structural and compositional features of human gallstones that influence in vitro gallstone dissolution in the cholesterol solvent monooctanoin. Gallstones were obtained from 86 consecutive patients who had at least three morphologically similar stones. One stone from each patient was dissolved in ethanol/ether to determine cholesterol and matrix composition. The remaining two matched stones were dissolved in either monoctanoin plus ethanol (n = 86) or monooctanoin plus 2-mercaptoethanol (n = 86). The thiol reducing agent 2-mercaptoethanol has been previously shown to solubilize the isolated gallstone matrix and to accelerate the dissolution of intact, small cholesterol stones. Stone matrix content and initial diameter had the most significant predictive value for stone dissolution (p < 0.0001 for each), whereas cholesterol content had no predictive value (p = 0.558). Stones incubated in monooctanoin containing 2-mercaptoethanol dissolved more rapidly than those incubated in monooctanoin plus ethanol (16.7% of initial weight per day vs. 13.8% of initial weight per day, p < 0.0001). Matrix content correlated significantly with the difference in dissolution rate between stones dissolved in monooctanoin plus ethanol or monooctanoin plus 2-mercaptoethanol (p < 0.0001). These data indicate that the matrix content of human cholesterol gallstones significantly inhibits in vitro stone dissolution in the cholesterol solvent monooctanoin. This finding may be relevant to the clinical dissolution of gallstones.
Brain atrophy by computerized tomography: Does brain matter matter?
Authors: Levy Lewis L.
Published: March 2007

Brain computerized axial tomography scans were performed in 18 consecutive liver cirrhosis patients with chronic persistent encephalopathy (8 alcoholic and 10 nonalcoholic) in order to evaluate the incidence of brain atrophy in this pathological condition. Fifteen patients of similar age with liver cirrhosis of Child’s class B but with acute episodic hepatic encephalopathy were studied in parallel. Brain atrophy was detected in 87.5% of alcoholic and in 50% of nonalcoholic liver cirrhosis patients with chronic persistent encephalopathy, whereas the patients with acute episodic encephalopathy were normal. The high frequency of brain atrophy in alcoholic patients with chronic encephalopathy can be attributed at least in part to the toxic effect of alcohol. The presence of brain atrophy in nonalcoholic liver cirrhosis patients with chronic persistent encephalopathy seems to indicate that the chronic exposure to toxins which are involved in the pathogenesis of hepatic encephalopathy leads to neuronal alterations which develop mainly in the cortex and which can be demonstrated by in vivo imaging only in a long-lasting state of coma. Moreover, alcohol and toxins causing hepatic encephalopathy seem to potentiate each other in inducing brain atrophy.
HLA class I antigen display on hepatocyte membrane in chronic hepatitis B virus infection: Its role in the pathogenesis of chronic type B hepatitis
Authors: Chu Chia-Ming , Shyu Wei-Chue , Kuo Ruey-Wen , Liaw Yun-Fan
Published: March 2007

It has been suggested that cytotoxic T cells are involved in the recognition and lysis of the infected hepatocytes in chronic hepatitis B virus infection, and that the target antigen is probably HBcAg which is displayed on the hepatocyte membrane during active viral replication. However, studies in other viral infection have demonstrated that cytotoxic T cells recognize viral antigen on the infected cells only in the context of HLA class I antigens. To test whether this mechanism is also operative in chronic hepatitis B virus infection, we studied the expression of HLA class I antigens in livers from 35 patients with chronic hepatitis B virus infection by indirect immunofluorescence using monoclonal antibody against HLA class I antigens. The blocking effect of monoclonal antibody against HLA class I antigens on the in vitro T cell cytotoxicity to autologous hepatocytes was also studied. The results revealed that HLA class I antigen was undetectable on the hepatocyte membrane in all of 10 HBeAg-positive carriers with minor hepatitic activity, whereas it was demonstrated in 15 (88%) of the 17 HBeAg-positive patients with chronic active liver disease and in 7 (87%) of the 8 anti-HBe-positive “normal” carriers. The in vitro T cell cytotoxicity to autologous hepatocytes in six HBeAg-positive patients with chronic active liver disease was significantly inhibited by preincubation of hepatocytes with monoclonal antibody (10 to 40 μg per ml) against HLA class I antigen, but not by monoclonal antibody against HLA class II antigens and non-HLA-associated surface molecules (Leu 11). These findings suggested that HLA class I antigens became detectable on hepatocyte membrane while significant histological activity developed in chronic hepatitis B virus infection, and that the effector cytotoxic T cells required HLA class I antigen as target structure(s).
Isolation of a human hepatic ferritin receptor
Authors: Adams Paul C. , Powell Lawrie W. , Halliday June W.
Published: March 2007

A human hepatic ferritin receptor has been isolated from human liver and has been purified using affinity chromatography. An affinity constant of 6.0 × 108 moles−1 liter was determined for the ferritin receptor. The molecular weight was estimated to be approximately 53,000 by gel electrophoresis. Binding of ferritin to the receptor coupled to a microparticulate support was specific for human liver ferritin with no binding of rat or porcine ferritin. Binding was unaffected by a 100-fold excess of human transferrin, human asialoo-rosomucoid and bovine albumin. After treatment of the receptor protein with trypsin, binding was not detected. The human hepatic ferritin receptor may play an important role in the uptake of iron into the hepatocyte in physiological and pathological conditions.
Characterization of H+ efflux pathways in rat hepatocytes
Authors: Anwer Sawkat M. , Nolan Kathleen
Published: March 2007

A pH-stat method was used to characterize H+ efflux pathways in hepatocytes in order to determine if Na+/ H+ and Ca++/H+ exchange are involved in H+ efflux from hepatocytes under basal conditions and if cyclic AMP analogs affect Na+/H+ exchange. Total H+ efflux of freshly prepared hepatocytes ranged from 10 to 15 nmoles per min per mg protein. A part of total H+ efflux (35 to 50%) was dependent on extracellular Na+. This Na+-dependent H+ efflux was (i) inhibited by amiloride with a half-maximal effect at 0.3 mM, (ii) inhibited by ouabain, (iii) dependent on extracellular pH and (iv) characterized by a Km of 15 ± 3 mM Na+ and a Vmax of 9 ± 0.07 nmoles per min per mg protein. Amiloride, ouabain and replacement of Na+ by choline also decreased intracellular pH determined from equilibrium distribution of dimethyloxazolidinedione. Li+ could partially substitute for Na+ in Na+-dependent H+ efflux and in maintaining intracellular pH. Efflux of CO2 and lactic acid from hepatocytes represented 80% of Na+-independent H+ efflux. Efflux of H+ in the presence and absence of Na+ was not significantly altered by extracellular Ca++ (<10 μM and 1.0 mM). Thus, Ca++/H+ exchange is unlikely to contribute significantly to total H+ efflux from hepatocytes. Cyclic AMP analogs, dibutyryl cyclic AMP and 8-bromo cyclic AMP, inhibited amiloride-sensitive Na+-dependent H+ efflux, and dibutyryl cyclic AMP decreased intracellular pH. These results indicate that (i) both Na+-independent and Na+-dependent mechanisms are involved in H+ efflux from hepatocytes, (ii) Na+-dependent H+ efflux represents Na+/H+ exchange and is involved in maintaining intracellular pH and (iii) cyclic AMP analogs decrease intracellular pH by inhibiting Na+/H+ exchange.
Hepatocellular carcinoma in alcoholic liver disease: No evidence for a pathogenetic role of hepatitis B virus infection
Authors: Walter Eike , Blum Hubert E. , Meier Peter , Huonker Martin , Schmid Martin , Maier Klaus-Peter , Offensperger Wolf-Bernhard , Offensperger Silke , Gerok Wolfgang
Published: March 2007

Hepatocellular carcinoma tissues from HBsAg-negative patients with chronic alcoholic liver disease were investigated for the presence of hepatitis B virus DNA. Southern blot analyses of DNA extracted from the hepatocellular carcinomas were negative for hepatitis B virus DNA in all 17 patients examined, at a level of sensitivity of less than 0.01 genome equivalent per cell. Similarly, in liver tissues from another 30 patients with alcoholic cirrhosis without hepatocellular carcinoma, no hepatitis B virus DNA was detectable. We conclude that in our patients there is no molecular evidence for a contribution of hepatitis B virus infection to the development of hepatocellular carcinoma in alcoholic liver disease.
In Vitro Hepatitis B virus suppression of erythropoiesis is dependent on the multiplicity of infection and is reversible with anti-HBs antibodies
Authors: Zeldis Jerome B. , Farraye Francis A. , Steinberg Howard N.
Published: March 2007

Exposure of human bone marrow mononuclear cells to hepatitis B virus results in the suppression of the in vitro growth of several hematopoietic progenitor cells. We studied the degree of inhibition of erythroid progenitor cells that results as a function of the time of exposure of mononuclear cells to hepatitis B virus and the ratio of virus to mononuclear cells, the multiplicity of infection. With an overnight incubation of mononuclear cells with hepatitis B virus-containing sera, a multiplicity of infection of greater than one virus per mononuclear cell is required to observe significant inhibition of erythroid colony formation. This multiplicity of infection effect is also observed with purified Dane particles. Exposure of mononuclear cells to an increasing number of Dane particles results in a dose-dependent suppression of erythroid colony formation with significant inhibition observed with a multiplicity of infection of virus to mononuclear cells as low as 5:1. Murine monoclonal antibodies to HBsAg completely neutralize the hepatitis B virus-mediated inhibition of CFU-E while control antibodies do not. Purified HBsAg has no effect on colony formation.

In conclusion, the hepatitis B virus-mediated inhibition of erythrogenesis in vitro provides a basis for understanding the bone marrow depression observed during hepatitis B virus infections and may provide an in vitro model for examining hepatitis B virus infection.
Urinary neopterin levels in acute viral hepatitis
Authors: Reibnegger Gilbert , Auhuber Ingeborg , Fuchs Dietmar , Hausen Arno , Judmaier Gert , Prior Christian , Werner Ernst R. , Wachter Helmut
Published: March 2007

Elevated neopterin levels in blood or urine have been shown to be a marker for the activation of cell-mediated immunity in vitro and in vivo. To evaluate whether neopterin levels are elevated in patients with acute viral hepatitis, we measured urinary levels in 13 patients with hepatitis A, 26 with hepatitis B, 12 with non-A, non-B hepatitis, 8 with jaundice and/or cholestasis due to biliary and pancreatic disorders and 3 with alcoholic hepatitis and in 62 apparently healthy HBsAg carriers. Neopterin levels in patients with virus-induced hepatitis were significantly higher than those in patients with other diagnoses. Urinary neopterin levels were above normal in 49 of 51 patients with viral hepatitis and elevations during the course of hepatitis showed a pattern similar to that of the usual liver biochemical tests, suggesting that neopterin levels were related to the clinical activity of the viral disease. In patients with non-viral biliary and hepatic disorders, neopterin levels were usually normal and did not correlate with other liver biochemical tests. These findings suggest that cell-mediated immune mechanisms are activated during viral hepatitis and that neopterin measurement may be of value as an additional surrogate marker for non-A, non-B hepatitis.
IgG and IgM autoantiidiotype antibodies against antibody to HBsAg in chronic hepatitis B
Authors: Ibarra Miren Zuriñe , Mora Ignacio , Quiroga Juan Antonio , Bartolomé Javier , La Banda Faustino , Porres Juan Carlos , Carreño Vicente
Published: March 2007

Antibody directed against HBsAg carries idiotypic determinants that may induce an autoantiidiotype antibody response. We describe a solid-phase radioimmunoassay which allows specific detection of either IgG or IgM antibody to antibody directed against HBsAg. Among 138 chronic hepatitis B virus carriers, IgG autoantiidiotype was detected in 98 (71%) and IgM autoantiidiotype in 110 (80%). The autoantiidiotype reaction was blocked with antibody directed against HBsAg after removal of immune complexes by polyethylene glycol precipitation. The prevalence and levels of both classes of autoantiidiotype antibodies were highest in patients with hepatitis B virus DNA or HBeAg in serum. During follow-up, patients who lost hepatitis B virus DNA and HBeAg from serum had lower titers of autoantiidiotype and were less likely to have autoantiidiotype than patients who persisted in having hepatitis B virus DNA and HBeAg in serum. Thus, the presence and titer of autoantiidiotype correlated with serologic evidence of active viral replication in chronic hepatitis B. These findings suggest that the antibody directed against HBsAg response may play a role in modulating viral replication in chronic hepatitis B.
Decreased collagen accumulation by a prolyl hydroxylase inhibitor in pig serum-induced fibrotic rat liver
Authors: Fujiwara Kenji , Ogata Itsuro , Ohta Yasuhiko , Hayashi Shigeki , Mishiro Shunji , Takatsuki Katsuyoshi , Sato Yuzuru , Yamada Shinwa , Hirata Keichi , Oka Hiroshi , Oda Toshitsugu , Kawaji Hisanori , Matsuda Shinobu , Niiyama Yasuhiko , Tsukuda Ryoichi
Published: March 2007

Hepatic fibrosis was induced in rats by repeated i.p. injections of pig serum. The hepatic hydroxyproline content increased to 2.1 times the normal control level at 6 weeks and to 3.2 times at 10 weeks. When P-1894B, an inhibitor of prolyl hydroxylase, was administered, there was a dose-dependent inhibition of the increase to nearly normal control levels at 6 and 10 weeks. There was also by histology a dose-dependent reduction in the degree of hepatic fibrosis. Hepatocellular damage was minimal and its extent did not vary with the degree of fibrosis or the treatment. P-1894B dose dependently reduced the hydroxylation of peptidyl proline in the fibrotic liver. These data suggest that P-1894B inhibited hepatic fibrogenesis by direct action on collagen but not by protection against hepatocellular damage leading to collagen formation. A prolyl hydroxylase inhibitor may be a candidate for use in treatment of hepatic fibrosis.
Renal sodium retention in cirrhosis: Tubular site and relation to hepatic dysfunction
Authors: Wood Laurence J. , Massie Denise , McLean Allan J. , Dudley Francis J.
Published: March 2007

Renal sodium handling, assessed by the response to acute saline loading, was investigated in 14 well-compensated, nonascitic alcoholic cirrhotics and six normal controls. Urinary sodium excretion in cirrhotic patients (199 ± 141 μmoles per min) was significantly lower than in controls (387 ± 104 μmoles per min; p < 0.01) at 3 hr postinfusion. In contrast to controls, renal plasma flow and glomerular filtration rate did not increase in the cirrhotics in response to acute saline loading. Proximal fractional reabsorption of sodium was estimated by clearance techniques in the presence of a hypotonic diuresis. Cirrhotic subjects with impaired functional liver cell mass as assessed by antipyrine clearance were unable to decrease proximal fractional reabsorption of sodium significantly in response to saline loading.

Assessment in the cirrhotics included measurement of hepatic vein pressure gradient, indocyanine green extraction ratio, indocyanine green clearance, and antipyrine clearance as indices of portal pressure, intrahepatic shunting, hepatic blood flow and functional hepatocellular mass, respectively. Urinary sodium excretion in the cirrhotics correlated strongly with antipyrine clearance (r = 0.839, p < 0.0001) and weakly with portal pressure (r = 0.562, p = 0.037). No correlation was seen with the other indices of hepatic blood flow and shunting.

The findings of this study suggest that alcoholic cirrhosis is associated with a decline in hepatocellular function which results in either a decreased clearance of a salt-retaining hormone or decreased synthesis of a natriuretic hormone. This hormone has as its principal effect the modulation of renal afferent vasomotor tone such that, in cirrhotics, renal plasma flow, glomerular filtration rate and proximal tubular sodium reabsorption cannot be altered in response to a salt load. Release of this hormone may be influenced by the degree of sinusoidal hypertension or hepatic venous outflow resistance.
Diet composition and surgical technique influence the postoperative recovery of portacaval shunted rats
Authors: Jerkins Ann A. , Steele Robert D.
Published: March 2007

In a series of experiments, rats were subjected to end-to-side portacaval shunts using either suture or nonsuture surgical procedures. Rats were maintained on cereal-based or purified diets in pellet form. All rats recovered preoperative body weights within the experimental periods; however, recovery of preoperative body weight was influenced by surgical technique and diet composition. Portacaval shunted rats fed a cereal-based diet required a longer period of time (14 days) to reattain preoperative body weights when compared to portacaval shunted rats fed a purified diet (7 days). Once preoperative body weight was recovered, growth rates of portacaval shunted rats were parallel to those of sham-operated controls. Rats with a suture-portacaval shunt appeared most sensitive to the feeding of a cereal-based diet. All portacaval shunted rats and sham controls fed a purified diet regained preoperative body weights within 7 days after surgery. Sham controls fed either a cereal-based or purified diet recovered preoperative body weights within an average of 4 days. Suture-portacaval shunted rats consuming a pellet form cereal-based diet showed a low feed efficiency which could be reversed by feeding a pellet form purified diet.

Rats subjected to a nonsuture glue-portacaval shunt and fed a cereal-based diet showed 50% lower feed efficiencies than did glue-portacaval shunted rats fed a purified diet. Portacaval shunted rats decreased their consumption of cereal-based diets but not of purified diets postoperatively. These reductions in food intake may be responsible for the growth delays observed in portacaval shunted rats and may explain some of the discrepancies in the literature concerning metabolite determinations since the nutritional and metabolic states of growing and nongrowing animals are not equivalent. From these studies we conclude that the surgical procedure used in the construction of a portacaval shunt as well as the postoperative diet composition are major factors which influence the postoperative performance of the portacaval shunted rat.
Effects of vasopressin on the intravariceal pressure in patients with cirrhosis: Comparison with the effects on portal pressure
Authors: Bosch Jaime , Bordas Josep M. , Mastai Ricardo , Kravetz David , Navasa Miquel , Chesta Jaime , Pizcueta Pilar M. , García-Pagán Juan C. , Rodés Joan
Published: March 2007

The present study investigated to what extent measurements of wedged and free hepatic venous pressures adequately reflect the effects of vasopressin at the esophageal varices in patients with cirrhosis. Eleven patients undergoing therapeutic sclerotherapy were studied by measuring wedged hepatic venous pressure, intravariceal pressure, free hepatic venous pressure, superior vena cava pressure and the intravascular pressure gradients wedged hepatic venous pressure-free hepatic venous pressure and intravariceal pressure-superior vena cava pressure, prior to and after vasopressin injection (1 IU, iv). Vasopressin caused a significant reduction in intravariceal pressure (from 22.5 ± 9.4 to 19.2 ± 8.4 mm Hg, p < 0.001). Measurement of wedged hepatic venous pressure and free hepatic venous pressure closely reflected the reduction in variceal pressure. Thus, wedged hepatic venous pressure decreased by 16 ± 11%, which is close to the 14 ± 7% change in intravariceal pressure, and the 23 ± 12% fall in the pressure gradient wedged hepatic venous pressure-free hepatic venous pressure was mirrored by the 26 ± 10% change in intravariceal pressure-superior vena cava pressure. These pressure gradients decreased more than the absolute pressures (intravariceal pressure and wedged hepatic venous pressure) due to concomitant increases in superior vena cava pressure (1.9 ± 1.9 mm Hg) and free hepatic venous pressure (0.6 ± 1.9 mm Hg). Since variceal wall tension, a parameter influencing the risk and severity of variceal bleeding, is modified by changes in intravariceal pressure but not by changes in superior vena cava pressure, our data suggest that the favorable effect of vasopressin is best indicated by the moderate fall in intravariceal pressure than by the greater reductions in the intravascular pressure gradients. This might explain the somehow deceiving results of vasopressin therapy for variceal hemorrhage. In addition, the study shows that the simple and safe technique of hepatic vein catheterization adequately reflects the effects of vasopressin on variceal pressure.
Hepatotoxic bile acids increase cytosolic Ca++ activity of isolated rat hepatocytes
Authors: Anwer Sawkat M. , Engelking Larry R. , Nolan Kathleen , Sullivan Dianne , Zimniak Peter , Lester Roger
Published: March 2007

Effects of bile acids on cystolic Ca++ activity and cell viability of isolated rat hepatocytes were studied to test the hypothesis that bile acids may produce hepatotoxicity by increasing cystolic Ca++ activity. Changes in cystolic Ca++ activity were calculated from time-dependent changes in fluorescence of quin-2 loaded hepatocytes. Release of lactate dehydrogenase and changes in propodium iodide fluorescence were used to assess cell viability. Bile acids studied were unconjugated and taurine-conjugated cholate, chenodeoxycholate (and taurochenodeoxycholate), deoxycholate (and taurodeoxycholate) and lithocholate (and taurolithocholate). With the exception of cholate and taurocholate, bile acids increased cystolic Ca++ activity within 10 to 30 sec in a concentration-dependent fashion (0.05 to 1.0 mM) and in the order lithocholate = taurolithocholate > chenodeoxycholate = taurochenodeoxycholate = deoxycholate = taurodeoxycholate. The initial increase in cystolic Ca++ activity by bile acids was not due to cell damage, since bile acid-induced decreases in cell viability were not significant until 2 to 3 min. At higher concentrations of unconjugated bile acid, there was a secondary increase in quin-2 fluorescence corresponding temporally to the increase in propodium iodide fluorescence, indicating cell damage after the initial increase in cystolic Ca++ activity. The ability of conjugated and unconjugated bile acids to increase cystolic Ca++ activity was abolished and decreased (60 to 90%), respectively, in the absence of extracellular Ca++, indicating that extracellular Ca++ is the major source of the bile acid-induced increase in cystolic Ca++ activity. Conjugated bile acids at lower concentrations (0.2 mM taurolithocholate and 0.5 mM taurodeoxycholate and taurochenodeoxycholate), but not at higher concentrations (0.5 mM taurolithocholate and 1.0 mM taurodeoxycholate and taurochenodeoxycholate), failed to produce cell damage in the absence of extracellular Ca++. This study showed, for the first time, that bile acids increase cystolic Ca++ activity, and that the increase in cystolic Ca++ activity precedes cell damage. These results raise the possibility that the hepatotoxic effect of bile acids is, at least in part, related to their ability to increase cystolic Ca++ activity.
Cholesterol nucleation from its carriers in human biles
Authors: Peled Y. , Halpern Z. , Baruch R. , Goldman G. , Gilat T.
Published: March 2007

This study was performed to determine whether biliary cholesterol nucleates primarily from vesicles or micelles. Twenty gallbladder biles and 12 hepatic biles from patients with gallstones as well as 16 model biles were examined. The nucleation times (days) of the biles as well as their isolated vesicular and micellar fractions were determined and their lipid composition was analyzed. In 41 of 46 comparisons, cholesterol nucleated faster from vesicles than micelles; in only one case was the opposite found. The mean (± S.D.) nucleation times of vesicles and micelles in gallbladder biles were 8.9 ± 5.4 vs. 15.4 ± 8.6, in hepatic biles 14.6 ± 9.4 vs. 20.6 ± 9.1, and in model biles 9.0 ± 3.7 vs. 18.9 ± 9.1 days, respectively. All these differences were significant (p < 0.005). Gallbladder biles (n = 7) devoid of vesicles nucleated more slowly (9.0 ± 9.5 days), as compared to gallbladder biles (n = 13) containing vesicles (3.8 ± 2.2 days). The nucleation time of gallbladder and hepatic biles was significantly correlated with the nucleation time of the vesicles from these biles (r = 0.847, p < 0.05). There was no correlation with the nucleation time of micelles from the same biles. The percentage of cholesterol carried by vesicles in bile was positively correlated to the molar percentage of biliary cholesterol and the cholesterol saturation index and negatively correlated to the molar percentage of bile salts. Our data suggest that phospholipid vesicles are the major vehicle for cholesterol precipitation in bile as well as an important determinant of the nucleation time of bile.
Autoantibodies against nuclear envelope-associated proteins in primary biliary cirrhosis
Authors: Lozano Francisco , Parés Albert , Borche Luis , Plana Montserrat , Gallart Teresa , Rodés Joan , Vives Jordi
Published: March 2007

An antinuclear immunofluorescence pattern displaying a thin ring confined to the nuclear envelope was assessed in sera from 38 patients with primary biliary cirrhosis and in sera from a control group of 277 patients with other antinuclear antibody-positive diseases. This rim-like antinuclear reactivity was present in sera from 20 primary biliary cirrhosis patients (52.6%) but in only two patients from the control group (0.7%) (p < 0.001). Furthermore, this autoantibody was present in three of four primary biliary cirrhosis patients without antimitochondrial antibodies. Presence of this rim-like pattern in primary biliary cirrhosis did not correlate with the presence of associated autoimmune diseases nor with other clinical, biochemical, nor histological features of the disease.

The antigenic specificity of sera displaying this antinuclear immunofluorescence pattern was characterized by Western blot analysis using an antigenic extract containing nuclear envelope proteins purified from rat liver. Sixteen of the 20 positive sera showed a common pattern of reactivity with a set of nuclear envelope-associated proteins approximately 200 kD in size.

In conclusion, sera from primary biliary cirrhosis patients showing a rim-like fluorescent nuclear pattern have antinuclear autoantibodies that react specifically with components of the nuclear envelope. The high specificity of these new autoantibodies in primary biliary cirrhosis indicate that they might be a serological marker of the disease, particularly useful in patients without antimitochondrial antibodies.
Hypertriglyceridemia: A relative contraindication to the use of bile acid-binding resins?
Authors: Denke Margo A. , Grundy Scott M.
Published: March 2007

Bile acid binding resins are indicated for treatment of elevated plasma low-density lipoprotein cholesterol concentrations. In normoglyceridemic patients, plasma concentrations of low-density lipoprotein cholesterol and total cholesterol are closely linked, and for this reason resin treatment of elevated total cholesterol levels in these patients is rational and warranted. Hypertriglyceridemic patients may also have elevated total cholesterol concentrations, and several such patients have been treated with resin. However, resin therapy in these patients is hazardous, since the elevated cholesterol level mainly results from increased plasma concentrations of very-low-density lipoproteins or chylomicrons rather than low-density lipoproteins. In these patients, resin treatment has either no effect or an adverse effect on plasma triglyceride and cholesterol concentrations. The data presented show that fewer than 5 percent of patients whose total plasma triglyceride concentration exceeded 500 mg/dl had elevated low-density lipoprotein cholesterol concentrations, irrespective of total plasma cholesterol concentrations, and no patient whose plasma triglyceride concentration exceeded 1,000 mg/dl had elevated low-density lipoprotein cholesterol levels. Treatment with bile acid binding resins in hypercholesterolemic patients is contraindicated in the presence of hypertriglyceridemia.
Transplantation of microcarrier-attached hepatocytes into 90% partially hepatectomized rats
Authors: Demetriou Achilles A. , Reisner Andrew , Sanchez Jay , Levenson Stanley M. , Moscioni Albert D. , Chowdhury Roy J.
Published: March 2007

We previously reported a method of intraperitoneal transplantation of liver cells attached to collagen-coated microcarriers, which resulted in prolonged survival and function of the transplanted cells. In the present study, we evaluated the efficacy of liver cell transplantation in providing metabolic support during acute liver insufficiency induced by 90% partial hepatectomy in rats. Ninety per cent of the liver mass (all lobes except the caudate lobe) was resected, and the rats were provided with 5% dextrose orally ad libitum upon regaining consciousness. This regimen results in severe hypoglycemia and death within 48 hr. When microcarrier-attached liver cells were transplanted into syngeneic and allogeneic recipients 3 days prior to 90% partial hepatectomy, significantly higher blood glucose levels were observed (p < 0.01), compared to the levels in control rats which received injections of microcarriers, liver cells or medium alone. There was a marked improvement in longterm survival (40% survived longer than 28 days; p < 0.001) in rats transplanted with microcarriers-attached cells. None of the rats given injections of microcarriers, liver cells or medium alone survived beyond 5 days. When liver cells alone or attached to microcarriers were injected intraperitoneally immediately after 90% partial hepatectomy, all rats became hypoglycemic and died within 48 hr, suggesting that vascularization of the transplant is required for function of the transplanted hepatocytes. The results indicate that intraperitoneal transplantation of microcarrier-attached hepatocytes prior to 90% partial hepatectomy in rats provides acute metabolic support resulting in improved survival.
Free amino acids in plasma and skeletal muscle of patients with liver cirrhosis
Authors: Montanari Alberto , Simoni Isabella , Vallisa Daniele , Trifirò Antonio , Colla Rossana , Abbiati Roberto , Borghi Loris , Novarini Almerico
Published: March 2007

Free amino acids were measured under postabsorptive conditions in plasma and intracellular water of skeletal muscle obtained by needle biopsy in nine healthy controls and 14 subjects suffering from clinically stable liver cirrhosis. The aromatic amino acids phenylalanine and tyrosine in cirrhotics were elevated to the same extent in plasma and in muscle water. Branched-chain amino acids were uniformly reduced in plasma, but in muscle water only valine was significantly lower (222 ± 92 μmoles per kg intracellular water vs. 368 ± 82, p < 0.001), while isoleucine (142 ± 63 vs. 103 ± 30), leucine (223 ± 88 vs. 226 ± 36) and branched-chain amino acids as a whole (589 ± 186 vs. 681 ± 88) were normal or elevated with an increased muscle:plasma ratio (3.12 ± 2.03 vs. 1.41 ± 0.37, p < 0.05 for isoleucine; 3.00 ± 1.28 vs. 1.85 ± 0.27, p < 0.025 for leucine; 2.24 ± 0.64 vs. 1.69 ± 0.13, p < 0.05 for total branched-chain amino acids.

Our data show that, in cirrhosis, plasma concentrations of branched-chain amino acids do not reflect their levels in muscle cellular water; only the intracellular pool of valine is severely depleted. This suggests that higher amounts of valine supplementation may be useful in nutritional treatment of liver cirrhosis.

The elevated muscle:plasma gradients for branched-chain amino acids may result from abnormalities in their transport through muscle-plasma membrane. These abnormalities may contribute to the reduced basal rate of net muscle branched-chain amino acid release and, in turn, to the low fasting plasma levels of these amino acids in liver cirrhosis. The altered intra- and extracellular distribution of branched-chain amino acids should also be taken into account when interpreting metabolic studies on turnover or clearance of branched-chain amino acids in cirrhotic patients.
Activation of murine kupffer cell tumoricidal activity by liposomes containing lipophilic muramyl dipeptide
Authors: Phillips Nigel C. , Rioux John , Tsao Ming-Sound
Published: March 2007

The ability of liposomes containing a lipophilic muramyl dipeptide, N-acetylmuramyl-l-alanyl-d-isoglutamine-glycerol dipalmitate, to induce Kupffer cell tumoricidal activity has been investigated. Liposomal N-acetylmuramyl-l-alanyl-d-isoglutamine-glycerol dipalmitate was 16-fold more potent than liposomal N-acetylmuramyl-l-alanyl-d-isoglutamine and 2,400-fold more potent than N-acetylmuramyl-l-alanyl-d-isoglutamine in inducing Kupffer cell tumoricidal activity in vitro. A single i.v. injection of liposomes containing N-acetylmuramyl-l-alanyl-d-isoglutamine-glycerol dipalmitate was capable of inducing Kupffer cell tumoricidal activity as measured against B16-melanoma cells after Kupffer cell isolation. Maximal cytotoxic activity was obtained with μg muramyl dipeptide-glycerol dipalmitate encapsulated within liposomes: doses of 10 or 100 μg inhibited tumoricidal activity. Kupffer cells from mice treated with liposomes containing N-acetylmuramyl-l-alanyl-d-isoglutamine-glycerol dipalmitate remained cytotoxic for at least 6 days after injection. Liposomal N-acetylmuramyl-l-alanyl-d-isoglutamine was significantly less potent than liposomal N-acetylmuramyl-l-alanyl-d-isoglutamine-glycerol dipalmitate in inducing Kupffer cell tumoricidal activity in situ. N-Acetylmuramyl-l-alanyl-d-isoglutamine was capable of inducing Kupffer cell tumoricidal activity in vitro: its failure to induce tumoricidal activity in situ at doses of 1,000 μg demonstrates the utility of liposomal carriers for the in vivo activation of Kupffer cells by muramyl dipeptides.
Affinities and densities of high-affinity [3H]muscimol (GABA-A) binding sites and of central benzodiazepine receptors are unchanged in autopsied brain tissue from cirrhotic patients with hepatic encephalopathy
Authors: Butterworth Roger F. , Lavoie Joël , Giguère Jean-François , Pomier-Layrargues Gilles
Published: March 2007

The integrity of GABA-A receptors and of central benzodiazepine receptors was evaluated in membrane preparations from prefrontal cortex and caudate nuclei obtained at autopsy from nine cirrhotic patients who died in hepatic coma and an equal number of age-matched control subjects. Histopathological studies revealed Alzheimer Type II astrocytosis in all cases in the cirrhotic group; controls were free from neurological, psychiatric or hepatic diseases. Binding to GABA-A receptors was studied using [3H]muscimol as radioligand. The integrity of central benzodiazepine receptors was evaluated using [3H]flunitrazepam and [3H]Ro15-1788. Data from saturation binding assays was analyzed by Scatchard plot. No modifications of either affinities (Kd) or densities (Bmax) of [3H]muscimol of central benzodiazepine binding sites were observed. These findings do not support recent suggestions that alterations of either high-affinity GABA or benzodiazepine receptors play a significant role in the pathogenesis of hepatic encephalopathy.
Deficiency of protein C in patients with portal vein thrombosis
Authors: Orozco Hector , Guraieb Edmundo , Takahashi Takeshi , Garcia-Tsao Guadalupe , Hurtado Rafael , Anaya Roger , Ruiz-Arguelles Guillermo , Hernandez-Ortiz Jorge , Casillas Marco A. , Guevara Luis
Published: March 2007

Portal vein thrombosis has been considered idiopathic in 50% of cases reported in adults. Protein C deficiency is a recently described disorder characterized by a predisposition to develop thromboembolic disease.

We report the findings in two patients with portal hypertension and bleeding varices due to portal vein thrombosis in whom a deficiency of protein C was present. Both cases were very similar, with a history of recurrent episodes of systemic thromboembolic disease, mesenteric venous thrombosis that required intestinal resection and upper gastrointestinal bleeding from gastroesophageal varices. Portal hypertension as well as portal vein thrombosis were demonstrated. The hematologic work-up revealed a deficiency of protein C.

Both patients were subjected to the Sugiura procedure, and anticoagulation was instituted thereafter. At the time of surgery, a liver biopsy was performed, which was reported as “normal.” Two years and 3 months, respectively, after surgery both patients are in good condition.

We conclude that protein C deficiency should be investigated in all cases of portal vein thrombosis, especially in those with a history of thromboembolic disease elsewhere.
δ Infection in asymptomatic carriers of hepatitis B surface antigen: Low prevalence of δ activity and effective suppression of hepatitis B virus replication
Authors: Chen Pei-Jer , Chen Ding-Shinn , Chen Chiou-Rong , Chen Yu-Ying , Chen Hsu-Mei Hsu , Lai Ming-Yang , Sung Juei-Low
Published: March 2007

We examined the prevalence of serum anti-δ antibody among 769 intravenous drug abusers in Taiwan. δ infection was found extremely common in the HBsAg-positive carriers with drug abuse, because 128 (85%) of 151 carriers were positive for anti-δ. However, most of antibody titers were low (<1:5,000). By molecular hybridization, δ RNA genomes were detectable in only five (4%) of 128 asymptomatic carriers positive for anti-δ. The results suggested that most of them had previous, instead of ongoing, δ infection. We also studied the serum markers reflecting hepatitis B virus replication in these carriers and a control group. Hepatitis B e antigen was positive in only 12 (10%) of 115 anti-δ positive carriers in contrast to 22 (23%) of 95 age- and sex-matched HBsAg-positive, anti-δ negative volunteers donating blood (p < 0.025). Furthermore, in contrast to the close association between HBeAg and hepatitis B virus DNA generally present in HBsAg carriers (concordance in this series: 79%), among the 12 HBeAg-positive subjects of the δ infected group, only two, or 17%, had serum hepatitis B virus DNA (p < 0.003). Such suppressing effects did not require a simultaneous presence of the δ agent, as shown by the lack of δ RNA genomes in the serum by sensitive assay. We conclude that although δ superinfection is common in the asymptomatic HBsAg carriers with intravenous drug abuse in the nonendemic area of Taiwan, continuous δ activities are uncommon in them. In addition, the previous δ infection probably exerts effective suppression on the hepatitis B virus replication in these HBsAg carriers.