bluuebunny/crossref_metadata_2025 huggingface dataset:
Tauroursodeoxycholate and tauro-β-muricholate exert cytoprotection by reducing intrahepatocyte taurochenodeoxycholate content
Authors: Ohiwa Takayuki , Katagiri Kenji , Hoshino Makoto , Hayakawa Tomihiro , Nakai Tomio
Published: March 2007

Cytoprotection by tauroursodeoxycholic acid and tauro-β-muricholic acid against taurochenodeoxycholic acid-induced toxicity was examined with reference to intracellular bile acid content in primary cultured rat hepatocytes. In comparison with levels in the group administered taurochenodeoxycholic acid 1 mmol/L alone, lactate dehydrogenase levels in the culture medium decreased significantly in groups simultaneously administered taurochenodeoxycholic acid 1 mmol/L and tauroursodeoxycholic acid 0.5 to 2 mmol/L or tauro-β-muricholic acid. Results of the trypan blue uptake test indicated that the lactate dehydrogenase release was indeed caused by cell damage. After the administration of tauroursodeoxycholic acid 2 mmol/L or tauro-β-muricholic acid 2 mmol/L, intracellular taurochenodeoxycholic acid content was consistently reduced to half of that after administration of taurochenodeoxycholic acid alone. Simultaneous administration of dibutyl cyclic AMP also reduced intracellular taurochenodeoxycholic acid content and lactate dehydrogenase release. Being rinsed with tauroursodeoxycholic acid and tauro-β-muricholic acid after being precultured in taurochenodeoxycholic acid 1 mmol/L also markedly reduced their taurochenodeoxycholic acid content. Taurocholic acid caused limited reduction of intracellular taurochenodeoxycholic acid but not suppression of lactate dehydrogenase release. Taurodehydrocholic acid showed no reduction of taurochenodeoxycholic acid content and no decrease of lactate dehydrogenase release. Although only small amounts of tauroursodeoxycholic acid or tauro-β-muricholic acid were found to accumulate in hepatocytes, taurocholic acid increased as if replacing taurochenodeoxycholic acid. The results suggest that tauroursodeoxycholic acid or tauro-β-muricholic acid may exert cytoprotective effects by lowering intracellular taurochenodeoxycholic acid levels associated with their optimal hydrophilicity. (Hepatology 1993;17:470-476.)
A scanning electron microscopic study of liver microcirculation disarrangement in experimental rat cirrhosis
Authors: Gaudio Eugenio , Pannarale Luigi , Onori Paolo , Riggio Oliviero
Published: March 2007

Hepatic microcirculation has been related to liver function in several studies. The principle of this relationship lies in the sequential distribution of blood from the feeding vessels of the hepatic acinus to the central vein. This study was undertaken to investigate the progressive changes at different sites of the liver microvascular bed in the developing cirrhosis, both by light microscopy and scanning electron microscopy of corrosion casts. Experimental cirrhosis was induced with intragastric carbon tetrachloride. The most important vascular changes progressively observed are the reduction of the distance between the pre- and postsinusoidal vessels, the presence of newly formed shunting vessels bypassing the sinusoids and, finally, the development of a perinodular vascular plexus composed of pre- and postsinusoidal vessels. Newly formed vessels grow through preformed tissue septa. These vascular modifications make any zonal gradient hardly possible. The loss of the zonal gradient of perfusion could highly modify liver function, along with the structural changes of hepatic laminae. Hepatocyte regeneration cannot recover the original vascular relationships: this makes the morphological and functional destructuralization of cirrhotic liver irreversible. (Hepatology 1993;17:477-485.)
Pentoxifylline prevents fibrosis in an animal model and inhibits platelet-derived growth factor-driven proliferation of fibroblasts
Authors: Peterson Theresa C.
Published: March 2007

Liver fibrosis is a complex process characterized by two major events: fibroproliferation and increased collagen synthesis. The exact role of cytokines in the pathogenesis of hepatic fibrosis remains to be established, but platelet-derived growth factor clearly stimulates proliferation of fibroblasts and increases collagen synthesis. In in vitro studies, pentoxifylline, a methylxanthine, significantly reduced platelet-derived growth factor-driven proliferation of fibroblasts. Platelet-derived growth factor has also been identified as a fibroproliferative factor produced spontaneously by monocytes obtained from patients with liver disease. Long-term administration of pentoxifylline (16 mg/kg orally, 5 days/wk for 12 wk) in an animal model of liver fibrosis prevented elevations in γ-glutamyl transpeptidase and alkaline phosphatase levels and prevented the reduction in serum albumin level normally observed in this animal model of liver disease. The animal model used was a long-term, low-dose yellow phosphorus-induced model in pigs that reproducibly results in extensive fibrosis after 10 to 12 wk of treatment. Long-term administration of pentoxifylline also prevented the histological changes characteristic of fibrosis in this animal model. Collagen concentration was significantly elevated in liver sections obtained from animals receiving yellow phosphorus, compared with controls. Long-term pentoxifylline treatment resulted in significantly lower collagen concentrations in liver sections from animals receiving yellow phosphorus than in sections from animals receiving yellow phosphorus alone; this was supported by histological observation. Therefore administration of pentoxifylline prevented the biochemical and histological changes associated with an animal model of liver disease. Pentoxifylline will likely have an important therapeutic role in liver fibrosis. (Hepatology 1993; 17:486-493.)
Zonal changes of hepatobiliary taurocholate transport in intrahepatic cholestasis induced by 17α-ethinyl estradiol: A histoautoradiographic study in rats
Authors: Buscher Hans-Peter , Meder Inge , Macnelly Sabine , Gerok Wolfgang
Published: March 2007

The liver has a great reserve capacity for hepatobiliary bile salt transport. This study was performed to elucidate the significance of this capacity in ethinyl estradiol-induced cholestasis by direct visualization of the zonal involvement in taurocholate transport. The acinar distribution of [3H]taurocholate was determined by histoautoradiographical study of cryopreserved liver slices in normal rats and rats treated with ethinyl estradiol for 5 days. Silver grain densities over the different acinar zones were estimated on digitized image analysis. In control animals, histoautoradiographical study performed 4 min after the start of perfusion showed restriction of taurocholate to acinar zone 1. In contrast, in ethinyl estradiol-treated animals, taurocholate was also found in zone 2 and, in smaller concentrations, in zone 3. In control animals, the relative blackenings by silver grains of acinar zones 1, 2 and 3 were 66% ± 1.2%, 25% ± 1.6% and 5% ± 0.6%, respectively. After 5 days of ethinyl estradiol treatment, blackenings were 58% ± 1.5%, 36% ± 2.1% and 12% ± 0.8%, respectively. As early as 15 sec after injection of [3H]taurocholate, the bile canalicular areas of the cell plates and the bile ductules of ethinyl estradiol-treated animals were labeled as intensely as those of control animals. Our results demonstrate ethinyl estradiol-induced recruitment of the acinar zones 2 and 3 for hepatobiliary taurocholate transport. This recruitment may largely compensate for reduction of transport capacity of periportal hepatocytes in early cholestasis. (Hepatology 1993;17:494-499.)
Is vesicular exocytosis and membrane recycling a mechanism for secretin-induced choleresis in bile duct epithelium?
Authors: Gumucio Jorge J. , Cho Won Kyoo , Broder James L.
Published: March 2007

Intrahepatic bile duct epithelial cells, or cholangiocytes, contribute to bile secretion in response to hormones, including secretin. However, the mechanism by which secretin stimulates ductular bile flow is unknown. Since recent data in nonhepatic epithelia have suggested a role for exocytosis in fluid secretion, we tested the hypothesis that secretin stimulates exocytosis by isolated cholangiocytes. Cholangiocytes were isolated, from normal rat liver by a newly described method employing enzymatic digestion and mechanical disruption followed by immunomagnetic separation using specific monoclonal antibodies, and exocytosis was measured using a fluorescence unquenching assay employing acridine orange. Secretin caused a dose-dependent (10−12 - 10−7M) increase in acridine orange fluorescence by acridine orangeloaded cholangiocytes with a peak response at 10 min; the half-maximal concentration of secretin was 7 × 10−9M. The secretin effect was inhibited by preincubation of cholangiocytes with colchicine (30% inhibition, p<0.05) or trypsin (90% inhibition, p<0.001); no inhibition was seen with lumicolchicine and heatinactivated trypsin. Cholecystokinin, insulin, and somatostatin had no effect on fluorescence of acridine orange-loaded cholangiocytes; secretin had no effect on fluorescence of acridine orange-loaded hepatocytes or hepatic endothelial cells. Exposure of isolated cholangiocytes to secretin at doses that stimulated exocytosis caused a dose-dependent increase in cyclic AMP levels (218% maximal increase, p<0.05); moreover, an analogue of cyclic AMP stimulated exocytosis by cholangiocytes. Secretin had no effect on intracellular calcium concentration using Fura-2-loaded cholangiocytes assessed by digitized video microscopy. Our results demonstrate, for the first time, that secretin stimulates exocytosis by rat cholangiocytes. The effect is cell- and hormone-specific, dependent on intact microtubules, on a protein(s) on the external surface of cholangiocytes, and on changes in cellular levels of cyclic AMP. The results are consistent with the hypothesis that secretin-induced changes in bile flow may involve an exocytic process.
Significance of pre-S region-defective hepatitis B virus that emerged during exacerbation of chronic type B hepatitis
Authors: Minami Masahito , Okanoue Takeshi , Nakajima Etsuro , Yasui Koichiro , Kagawa Keizo , Kashima Kei
Published: March 2007

A defective form of the hepatitis B virus has been found in a patient with chronic type B hepatitis. Sequence analysis of the viral DNA after polymerase chain reaction amplification revealed a 117-base pair deletion (nucleotides 3129-53, subtype adr). This deletion includes the initiation codon of the pre-S2 region and a newly created in-frame stop codon in the pre-S1 region (nucleotide 3055) located 230 base pairs downstream from the pre-S1 initiation codon. This virus coexisted with the wild-type virus during the exacerbation period, as evidenced by an elevation of serum transaminase levels. It was not detected in the stable period, and the blood chemistry results were normal. We assayed antibodies against the mutationrelated region by enzyme immunoassay in serial serum samples to clarify the mechanism of the emergence of this variant virus. Antibodies against the pre-S2 region were negative; however, the antibody response against the pre-S1 epitopes coincided with the appearance of the variant virus. These findings suggest that an activated T-cell and B-cell response had developed against the pre-S1 region during hepatic inflammation in this patient and that, consequently, selection occurred for a pre-S antigen-defective mutant strain of the virus that might be resistant to such an immune response. (Hepatology 1993;17:558-563.)
A study of oral nutritional support with oxandrolone in malnourished patients with alcoholic hepatitis: Results of a department of veterans affairs cooperative study
Authors: Mendenhall Charles L. , Moritz Thomas E. , Roselle Gary A. , Morgan Timothy R. , Nemchausky Bernard A. , Tamburro Carlo H. , Schiff Eugene R. , McClain Craig J. , Marsano Luis S. , Allen John I. , Samanta Arun , Weesner Robert E. , Henderson William , Gartside Peter , Chen Thomas S. , French Samuel W. , Chedid Antonio
Published: March 2007

A Veterans Affairs cooperative study involving 273 male patients was performed to evaluate efficacy of oxandrolone in combination with an enteral food supplement in severe alcoholic hepatitis. All patients had some degree of protein calorie malnutrition. On an intention-to-treat basis, only minimal changes in mortality were observed. However, in patients with moderate malnutrition mortality on active treatment at 1 mo was 9.4% compared with 20.9% in patients receiving placebo. This beneficial effect was maintained so that after 6 mo on active treatment 79.7% of patients were still alive, compared with 62.7% of placebo-treated patients (p = 0.037). Improvements in both the severity of the liver injury (p = 0.03) and malnutrition (p = 0.05) also occurred. No significant improvement was observed with severe malnutrition. To better determine the effect on therapeutic efficacy, we compared results with those from a nearly identical population (cooperative study 119) treated with oxandrolone but not given the food supplement. Patients were stratified according to their caloric intake (greater than 2,500 kcal/day was considered adequate to supply energy needs and promote anabolism). For patients with moderate malnutrition and adequate caloric intake, oxandrolone treatment reduced 6-mo mortality (4% active treatment vs. 28% placebo [p = 0.002]). For patients with moderate malnutrition and inadequate calorie intake, oxandrolone had no effect on mortality (30% active treatment vs. 33% placebo). In cases of severe malnutrition, oxandrolone had no effect on survival. However, adequate caloric intake was associated with 19% mortality, whereas patients with inadequate intake exhibited 51% mortality (p = 0.0001). These results indicate that nutritional status should be evaluated in patients with alcoholic hepatitis. When malnutrition is present, vigorous nutrition therapy should be provided, and in patients with moderate malnutrition oxandrolone should be added to the regimen. (Hepatology 1993;17:564-576.)
Liver cell adenoma at the age of 3 years and transplantation 19 years later after development of carcinoma: A case report
Authors: Janes Christine H. , McGill Douglas B. , Ludwig Jurgen , Krom Ruud A. F.
Published: March 2007

A 3-yr-old child underwent biopsy of a nonresectable liver cell adenoma. She was well thereafter, but at the age of 22 yr, she underwent orthotopic liver transplantation because the lesion had grown. The α-fetoprotein level was 4,300. The specimen showed poorly differentiated hepatocellular carcinoma in a noncirrhotic liver. At this writing, the patient is well 32 mo after transplantation. (Hepatology 1993;17:583-585.)
Serum bile acids in primary biliary cirrhosis: Effect of ursodeoxycholic acid therapy
Authors: Poupon Renée E. , Chrétien Yves , Poupon Raoul , Paumgartner Gustav
Published: March 2007

Serum bile acid levels and distributions were studied every 6 mo in patients with primary biliary cirrhosis who were randomly assigned to receive ursodeoxycholic acid (13 to 15 mg/kg/day) (n = 73) or a placebo (n = 73) over a 2-yr period. In the ursodeoxycholic acid group, ursodeoxycholic acid was the predominant serum bile acid at 6 mo and throughout the 2-yr treatment period. The total concentration of endogenous bile acids decreased with a reduction in cholic acid (in the ursodeoxycholic acid group and the placebo group, respectively [mean :± S.E.]: 13.0 ± 2.2 and 12.6 ± 2.5 μmol/L at entry vs. 3.5 ± 0.6 and 9.0 ± 2.2 μmol/L at 2 yr; p < 0.002), chenodeoxycholic acid (in the ursodeoxycholic acid group and the placebo group, respectively: 12.1 ± 1.7 and 12.7 ± 2.3 μmol/L at entry vs. 5.8 ± 0.8 and 10.7 ± 2.2 μmol/L at 2 yr; p < 0.02) and 3β-hydroxy-δ5-cholenoic acid. The concentration of deoxycholic acid did not change, whereas that of lithocholic acid increased significantly (in the ursodeoxycholic acid group and the placebo group, respectively: 0.63 ± 0.06 and 0.81 ± 0.12 μmol/L at entry vs. 1.26 ± 0.12 and 0.90 ± 0.15 μmol/L at 2 yr; p < 0.001). These changes were independent of the histological stage of the disease. Thus during ursodeoxycholic acid administration the liver was exposed to a lower level of endogenous bile acids and to an increased concentration of ursodeoxycholic acid. These changes in circulating bile acids and their beneficial effects could be explained by the following mechanisms: (a) initially, ursodeoxycholic acid would directly increase hepatocyte excretion of bile acids; (b) their return to the liver would then be limited by an inhibitory effect of ursodeoxycholic acid on their intestinal reabsorption; and (c) liver cell metabolism and functions would be improved by the sustained reduction in the concentration of endogenous bile acids and the predominant presence of ursodeoxycholic acid. (Hepatology 1993;17:599-604.)
Decreased mitochondrial oxidation of fatty acids in pregnant mice: Possible relevance to development of acute fatty liver of pregnancy
Authors: Grimbert Sylvie , Fromenty Bernard , Fisch Cecile , Letteron Philippe , Berson Alain , Durand-Schneider Anne Marie , Feldmann Gerard , Pessayre Dominique
Published: March 2007

Severe impairment of the β-oxidation of fatty acids, as a consequence of a single factor or a combination of different causes, leads to microvesicular steatosis of the liver. In an effort to understand the mechanism(s) leading to the development of acute fatty liver of pregnancy in some women, we determined the effects of pregnancy on the mitochondrial oxidation of fatty acids in mice. In vivo, the rate of oxidation of the whole fatty-acid chain length was determined by measuring the rate of exhalation of [14C]CO2 after intragastric administration of a tracer dose of [U-14C]palmitic acid. [14C]CO2 exhalation was not significantly decreased at 14 days of gestation, but it had declined by 40% at 18 days of gestation (i.e., 24 to 48 hr before delivery). The rate of first β-oxidation cycle was assessed by measuring the rate of [14C]CO2 exhalation after administration of [1-14C]octanoic acid, [1-14C]butyric acid or [1-14C]palmitic acid. [14C]CO2 exhalation had declined by 60%, 46%, and 24% after administration of [1-14C]octanoic acid, [1-14C]butyric acid and [1-14C]palmitic acid, respectively, in 18-day-pregnant mice. Total hepatic lipids and triglycerides, expressed per gram of liver, remained unchanged in 18-day-pregnant mice. In vitro, the rate of mitochondrial β-oxidation (expressed per milligram of protein) had decreased by 47% at 18 days' gestation with [U-14C]palmitic acid as substrate and by 33% with [1-14C]octanoic acid but remained unchanged with [1-14C]palmitic acid. The activity of the tricarboxylic acid cycle, assessed by the formation of [14C]CO2 from [1-14C]acetic acid, had decreased by 24%. We conclude that the mitochondrial oxidation of fatty acids decreased during late-term pregnancy in mice as a consequence of both decreased mitochondrial β-oxidation of medium-chain fatty acids, and decreased activity of the tricarboxylic acid cycle. We suggest that this effect, in combination with other factors, may contribute to the development of fatty liver of pregnancy in some pregnant women. (Hepatology 1993;17:628-637.)
Cholesterol cholelithiasis in the prairie dog: Role of mucin and nonmucin glycoproteins
Authors: Afdhal Nezam H. , Gong Dahai , Niu Niu , Turner Bradley , Lamont Thomas J. , Offner Gwynneth D.
Published: March 2007

The aims of this study were to examine the effect of exogenous prostaglandin on mucin secretion and to determine the role of nonmucin glycoproteins on gallstone formation in the prairie dog model of cholesterol cholelithiasis. The concentration of total glycoprotein and nonmucin glycoproteins was measured in gallbladder bile from four groups of prairie dogs fed a control diet or a diet supplemented with 1.2% cholesterol with or without simultaneous subcutaneous administration of prostaglandin E1. Cholesterol feeding resulted in an increased concentration of concanavalin-A binding-proteins in gallbladder bile associated with an increase in pronucleating activity in vitro. Treatment with prostaglandin E1 and cholesterol feeding was associated with a significant increase in the incidence of cholesterol gallstone formation. Prostaglandin E1 treatment in the cholesterol-fed animals increased biliary concentrations of total glycoprotein and concanavalin-A-binding glycoproteins. Therefore the increased biliary glycoprotein level in cholesterolfed, prostaglandin E1-treated prairie dogs, which reflects higher levels of mucin and nonmucin glycoproteins, appears to be an important factor in gallstone formation. (Hepatology 1993;17:693-700.)
Effects of thyroxine on the expression of alcohol dehydrogenase in rat liver and kidney
Authors: Dipple Katrina M. , Qulali Mona , Ross Ruth Ann , Crabb David W.
Published: March 2007

We studied the effect of thyroxine on alcohol dehydrogenase activity, immunoreactive protein levels and messenger RNA levels in the livers of thyroidectomized and sham-operated male rats. Effects on kidney alcohol dehydrogenase activity were also examined. Shamoperated rats injected with 100 μg thyroxine/kg/day, which induced hyperthyroidism, showed a 30% decrease in liver and a 40% decrease in kidney alcohol dehydrogenase activity compared with sham-operated rats injected with vehicle. Hypothyroid rats exhibited a 1.5-fold increase in alcohol dehydrogenase activity in liver and kidney compared with thyroidectomized rats injected with a replacement dose of 20 μg thyroxine/kg/day. We saw a twofold and a 2.5-fold higher level of alcohol dehydrogenase activity in liver and kidney, respectively, of hypothyroid rats compared with hyperthyroid rats. These effects were not accounted for by nutritional differences; daily food intake did not differ between groups. Immunoreactive protein levels as seen on Western blots varied in the same direction as enzyme activity. Northern-blot analysis showed higher levels of liver alcohol dehydrogenase messenger RNA in hypothyroid rats compared with euthyroid rats. These studies show that liver alcohol dehydrogenase activity and protein levels are modulated by thyroxine at pathophysiologically relevant levels and that this effect is not due to changes in food intake; kidney alcohol dehydrogenase activity is regulated in parallel. The change in alcohol dehydrogenase activity appears to be controlled in part by pretranslational mechanisms in hypothyroid animals and by posttranslational mechanisms in hyperthyroid animals. (Hepatology 1993;17:701-706.)
Bidirectional transport of glutathione in hepatocyte membranes: Does glutathione efflux stimulate organic anion uptake?
Authors: Ballatori Ned
Published: March 2007

We determined the trans effects of extracellular reduced glutathione (GSH) on the rate of efflux of endogenous labeled GSH from freshly isolated rat hepatocytes. The presence of GSH (10 mM) in the medium significantly stimulated the fractional rate of efflux of [35S]GSH from 5.2 to 12.6%/15 min (p < 0.01). This effect was concentration-dependent, had sigmoid type of kinetics (D50 of 0.32 mM), and was reversible upon removal of external GSH. trans-Stimulation (counter-transport) was also observed with 5 mM oxidized glutathione (GSSG) and ophthalmic acid (fractional [35S]GSH efflux: 13.4% ± 4.1 and 8.8% ± 2.3 in 15 min, respectively, compared with control: 4.7 ± 2.5/15 min). Bromosulphthalein-glutathione (BSP-GSH, 5 mM) in Krebs buffer inhibited the fractional [35S]GSH efflux (1.1%/15 min), whereas in Cl−--free buffer, GSH efflux was stimulated (14.2%/15 min) compared with control. trans-Stimulation was independent of chloride. BSP-GSH cis-inhibited and trans-stimulated the initial rate of GSH transport in basolateral-enriched membrane vesicles (bLPM) but not in canalicular-enriched membrane vesicles (cLPM). γ-Glutamyl compounds also cis-inhibited and trans-stimulated GSH transport in bLPM vesicles. GSH-depleted hepatocytes incubated with 10 mM [35S]GSH accumulated more GSH than repleted cells, but the initial rate of uptake of radioactivity was faster in repleted cells. In contrast, repleted hepatocytes incubated with tracer or 50 μM [35S]GSH did not take up GSH. Thus, the sinusoidal membrane GSH transporter exhibits low affinity kinetics with sigmoid features for both GSH uptake and trans-stimulation of efflux, explaining the lack of uptake of GSH at low physiologic extracellular concentrations. Therefore, our findings support and explain the widely held view that GSH transport is unidirectional under physiologic conditions. However, the efflux of GSH may also occur in exchange for the uptake of organic anions and γ-glutamyl compounds. (J Biol Chem 1992;267:22256-22264.)
Assessment of lymphokine-activated killer activity and γ-interferon production in patients with small hepatocellular carcinomas
Authors: Saibara Toshiji , Maeda Takashi , Miyazaki Masako , Onishi Saburo , Yamamoto Yasutake
Published: March 2007

We have previously reported depressed γ-interferon production and depressed lymphokine-activated killer and natural killer activity in patients with relatively large hepatocellular carcinomas. These parameters were normal in cirrhosis. Some evidence had suggested a γ-interferon production defect as the main cause of depressed lymphokine-activated killer activity in hepatocellular carcinoma, (i.e., γ-interferon enhances lymphokine-activated killer and natural killer activity and γ-interferon antibody inhibits lymphokine-activated killer induction). However, we were unable to clinically define the precise mechanism operating here because γ-interferon production and lymphokine-activated killer activity were both defective in advanced hepatocellular carcinoma. In recent years, it has become possible to detect even small hepatocellular carcinomas on ultrasonography and to confirm them by fine-needle biopsy. In this study, we assessed those immune parameters in 48 patients with hepatocellular carcinomas less than 2 cm in diameter to confirm depressed immune function and to clarify the mechanism of these defects. Lymphokine-activated killer activity was defective in 31 patients (64.6%), whereas γ-interferon production was defective in only 1 of these patients (2.1%). This observation argues against the hypothesis that defective γ-interferon production is the primary defect and provides new insight into the mechanism of progression of defective immune function in hepatocellular carcinoma. Thirty-one of the 48 hepatocellular carcinoma patients were treated surgically, and these immune parameters were followed for 6 mo. The recovery of lymphokine-activated killer activity in all hepatocellular carcinoma patients with low lymphokine-activated killer activity suggests the tumor burden as the cause of defective lymphokine-activated killer activity. (Hepatology 1993;17:781-787.)
Renal effects of acute isosorbide-5-mononitrate administration in cirrhosis
Authors: Salmerón Joan M. , Del Arbol Luis Ruiz , Ginès Angels , García-Pagán Joan C. , Ginés Pere , Feu Faust , Claria Joan , Rivera Francisca , Bosch Jaume , Arroyo Vicente , Rodés Joan
Published: March 2007

The aim of this study was to assess the effects of an oral dose (20 mg) of isosorbide-5-mononitrate on systemic hemodynamics, kidney function, plasma renin activity and plasma aldosterone and atrial natriuretic peptide concentrations in 16 nonazotemic cirrhotic patients. Isosorbide-5-mononitrate significantly reduced cardiopulmonary pressures, cardiac output, peripheral vascular resistance, mean arterial pressure, renal-plasma flow, glomerular filtration rate, free water clearance, sodium excretion and atrial natriuretic peptide concentration and significantly increased renin and aldosterone values. Cardiopulmonary pressures, atrial natriuretic peptide, cardiac output and mean arterial pressure decreased to a similar extent in patients with (n = 9) and without ascites (n = 7). In patients with ascites we noted marked increases in plasma renin activity (3.7 ± 1.1 ng/ml/hr to 6.4 ± 1.8 ng/ml/hr; p = 0.01) and aldosterone level (61.1 ± 17.5 ng/dl to 108.4 ± 36.1 ng/dl; p = 0.01). In contrast, in patients without ascites the elevation of plasma renin activity (0.5 ± 0.16 ng/ml/hr to 0.95 ± 0.27 ng/ml/hr; p = 0.02) and aldosterone level (5.9 ± 1.3 ng/dl to 12.3 ± 3.8 ng/dl; p = 0.02) was mild, and in no case did these parameters increase over the upper normal limit. Isosorbide-5-mononitrate produced a significantly greater reduction of glomerular filtration rate (-21.4% ± 3.3% vs. −8.9% ± 4.2%; p = 0.03) and free water clearance (−82.4% ± 16.1% vs. −34.5% ± 12.3%; p = 0.03) in patients with ascites than in those without. We also saw a trend toward a greater decrease of renal plasma flow in ascitic patients (−29.2% ± 7.1% vs. −9.8% ± 9.8%; p = 0.1). Urinary sodium excretion showed a similar decrease (−43.7% ± 9.8% vs. −56.7% ± 12.5%) in the two groups. These results indicate that the administration of a single oral dose of isosorbide-5-mononitrate stimulates the renin-aldosterone system and impairs kidney function in patients with cirrhosis, especially in those with ascites. (Hepatology 1993;17:800-806.)
Biliary abnormalities associated with extrahepatic portal venous obstruction
Authors: Khuroo Mohammed Sultan , Yattoo Ghulam Nabi , Zargar Showkat Ali , Javid Gul , Dar Mohammed Yousuf , Khan Bashir Ahmed , Boda Mohammed Iqbal
Published: March 2007

We prospectively studied 21 consecutive patients with extrahepatic portal venous obstruction for evidence of biliary tract disease. Two patients were first seen with extrahepatic cholestasis; another had recurrent cholangitis. All three patients with clinically manifest biliary disease were adults. Another five patients had icterus on clinical examination. Liver function tests revealed elevated bilirubin levels in 14 patients (66.6%), elevated alkaline phosphatase levels in 17 (80.9%) and elevated serum ALT levels in 8 (38.0%). Endoscopic retrograde cholangiography revealed abnormal findings in 17 patients (80.9%). The changes involved the common bile duct (66.6%) more often than they did the hepatic bile ducts (38.1%). Cholangiographic abnormalities included strictures (52.4%), caliber irregularity (23.8%), segmental upstream dilatation (42.8%), ectasia (9.5%), collateral veins causing extraluminal bile duct impressions (14.3%), displacement of ducts (9.5%), angulation of ducts (4.7%) and pruning of intrahepatic ducts (9.5%). The pathogenesis of such cholangiographic abnormalities is unknown. However, possible factors in such changes include collateral veins bridging the blocked portal vein, causing bile duct impressions; fibrous scarring of porta hepatis, causing angulation of bile duct; and ischemic injury to bile duct, leading to stricture formation and caliber irregularity. Biliary disease is important in the clinical outcome of patients with extrahepatic portal venous obstruction because variceal sclerotherapy has prolonged the life expectancies of such patients. (Hepatology 1993;17:807-813.)
Abnormalities in proximal small bowel motility in patients with cirrhosis
Authors: Chesta Jaime , Defilippi Claudia , Defilippi Carlos
Published: March 2007

Because altered intestinal motility could be involved in the pathogenesis of small intestine bacterial overgrowth observed in some patients with cirrhosis, we investigated fasting proximal small bowel motility in 16 cirrhotic patients and 8 healthy controls. In addition, the effects of oral tetracycline administration on duodenal motility were investigated in seven cirrhotic patients with evidence of bacterial overgrowth. The mean duration and characteristics of the migrating motor complex were analyzed. Cyclic activity was observed in all healthy controls. It was absent in two cirrhotic patients showing a prolonged phase 2-like pattern. The duration of cycles was significantly longer in the remaining 14 patients with cirrhosis (166 ± 19 min) compared with controls (81 ± 14 min; p < 0.02). This difference was caused by a prolonged phase 2 (138 ± 19 min in patients with cirrhosis vs. 52 ± 11 min in controls; p < 0.02). Marked changes in the contraction pattern during phase 2 were noted in cirrhotic patients. They were characterized by multiple clusters (frequency, 12 ± 1/hr; duration, 38 ± 3 sec) of contractions (frequency, 11 ± 1 cpm) separated by quiescent periods (duration, 2.4 ± 0.2 min). This motility profile filled up 58% ± 8% of the total duration of phase 2, and it was observed in patients with and without bacterial overgrowth. Treatment with tetracycline was followed by only mild modifications, such as a reduction of the fraction of phase 2 occupied by multiple-clustered contractions. In conclusion, an altered proximal small bowel motility has been observed in patients with cirrhosis. These disturbances appear not to be dependent on the presence of bacterial overgrowth. (Hepatology 1993;17:828-832.)
Induction of multidrug resistance gene expression during cholestasis in rats and nonhuman primates
Authors: Schrenk Dieter , Gant Timothy W. , Preisegger Karl-Heinz , Silverman Jeffrey A. , Marino Pamela A. , Thorgeirsson Snorri S.
Published: March 2007

P-glycoprotein, an energy-dependent plasma membrane drug-efflux pump capable of reducing the intracellular concentration of a variety of hydrophobic xenobiotics, is encoded by mdr 1, a member of the multidrug-resistant (mdr) gene family. The physiological function of this protein is unknown. Because of its location on the bile canalicular domain of the hepatocyte, we and others have hypothesized that P-glycoprotein may have a physiological role as a biliary transporter of xenobiotics and endobiotics and that its expression may therefore be altered in cholestasis. Both obstructive and α-naphthylisothiocyanate-induced cholestasis increased mdr 1a and 1b gene expression in rat liver. Hepatic P-glycoprotein levels were also increased, and the protein remained localized at the biliary hepatocyte domain. Induction of mdr 1a and mdr 1b gene expression in rat liver was accomplished by means of increased transcription. α-Naphthylisothiocyanate-induced cholestasis in cynomolgus monkeys increased hepatic expression of both the mdr 1 and 2 genes. To investigate the possible role of P-glycoprotein as a biliary efflux transporter, biliary excretion of vinblastine, a representative substrate of P-glycoprotein, was studied in rats. Increased hepatic mdr messenger RNA and P-glycoprotein levels, mediated by the xenobiotic inducer 2-acetylaminofluorene, resulted in a significant increase in biliary excretion of vinblastine, which was antagonized by the P-glycoprotein inhibitor verapamil. These findings suggest that P-glycoprotein functions as a biiary efflux pump for xenobiotics and, possibly, for unidentified physiological inducers that may mediate increased transcription of the mdr gene observed during cholestasis. (Hepatology 1993;17:854-860.)
Coexpression of erythropoietin and heme oxygenase genes in Hep3B cells
Authors: Lutton John D. , Griffin Margaret O. , Nishimura Miki , Levere Richard D. , Kappas Attallah , Abraham Nader G. , Shibahara Shigeki
Published: March 2007

Exposure of Hep3B cells to metalloporphyrins (tinprotoporphyrin and heme) or cobalt chloride resulted in the production of a significant number of heme oxygenase transcripts, erythropoietin transcripts or both, as indicated by in situ hybridization. Exposure to heme 10 μmol/L resulted in a 30-fold to 40-fold increase in cells expressing erythropoietin messenger RNA (erythropoietin-positive cells) by 6 hr; this increased level remained elevated for 24 hr. Tin-protoporphyrin (10 μmol/L) produced an eightfold to 10-fold increase in erythropoietin RNA within 40 min. This value then returned to control levels by 60 min. Exposure to cobalt chloride (100 μmol/L) resulted in a 20-fold to 30-fold increase in erythropoietin expression for 5 to 20 min, returning to control by 40 min. Additionally, nuclear runoff assays demonstrated that the increase in heme oxygenase or erythropoietin messenger RNA accumulation by cobalt chloride appeared to be a result of stimulated transcription of the heme oxygenase and erythropoietin genes. However, the pattern for heme oxygenase messenger RNA induction was different from that for erythropoietin expression. Heme produced an immediate expression of heme oxygenase RNA (50-fold within 5 min) and a second sustained response during the next 24 hr. Tin-protoporphyrin also produced an immediate response (40-fold within 5 min) and remained elevated (20-fold) for 6 hr. Cobalt chloride produced a 22-fold increase within 20 min and returned to the control value by 1 hr. Thus both erythropoietin and heme oxygenase genes appear to be expressed after treatment with tin-protoporphyrin, heme or cobalt chloride; however, the time and patterns of expression are different. The most significant feature of coexpression appears to be that induced by heme, where heme oxygenase is immediately expressed (5 min) with a second sustained expression during the next 10 to 24 hr, whereas erythropoietin sustained expression for 3 to 24 hr. (Hepatology 1993;17:861-868.)
Evidence for involvement of oxygen free radicals in bile acid toxicity to isolated rat hepatocytes
Authors: Sokol Ronald J. , Devereaux Michael , Khandwala Rhashmi , O'Brien Kevin
Published: March 2007

The mechanisms by which hydrophobic bile acids are toxic to the liver are unknown. To determine whether the generation of free radicals is involved in the hepatotoxicity of bile acids, freshly isolated rat hepatocytes were incubated with individual bile acids (100 to 200 μmol/L) for 4 hr. Hepatocyte viability (trypan blue exclusion) declined to 40% to 50% in incubations with taurochenodeoxycholic acid and taurolithocholic acid, whereas taurocholic acid and tauroursodeoxycholic acid were not toxic. Lipid peroxidation was significantly associated with the loss of cell viability. Preincubation with different antioxidants - D-α-tocopheryl succinate, D-α-tocopherol, diphenyl-p-phenylenediamine, superoxide dismutase, catalase, superoxide dismutase + catalase, deferoxamine or apotransferrin - protected against the loss of viability and inhibited lipid peroxidation in cells incubated with 200 μmol/L taurolithocholic acid. α-Tocopheryl succinate added after 90 min of incubation with taurolithocholic acid ameliorated further hepatocyte toxicity and lipid peroxidation. Incubation of hepatocytes with 500 μmol/L of taurochenodeoxycholic acid or taurolithocholic acid under a low oxygen tension (9% O2) similarly caused lipid peroxidation and cell injury that was reversed by preincubation with D-α-tocopherol. These data suggest that oxygen free radicals may be involved in the pathogenesis of bile acid hepatotoxicity. (Hepatology 1993;17:869-881.)
Role of the cyclic AMP response element in rat fibronectin gene expression
Authors: Miao Sun , Suri Parmjeet K. , Shu-Ling Liu , Abraham Ann , Cook Nanette , Milos Patrice , Zern Mark A.
Published: March 2007

Fibronectin expression is of considerable importance in normal and fibrotic liver. Plasma fibronectin levels are correlated with good prognosis in liver failure, and cellular fibronectin plays a crucial role in fibrogenesis. In this study, we observed that the H4II rat hepatoma cell line does not express fibronectin. Furthermore, a recombinant vector (pFGH) containing the promoter elements of the fibronectin gene showed no promoter function when transfected into this cell line. However, pFGH was actively expressed in L-cells and rat skin fibroblasts, cell types that express large amounts of endogenous fibronectin. To study the mechanisms regulating fibronectin expression, we evaluated the transcriptional regulatory elements of the rat fibronectin gene by mutational analysis and DNA-protein binding studies. Deletional mutation analysis showed that the sequences between positions - 164 and -90 are essential for promoter activity. This region contains the consensus binding sites for CCAAT and the cyclic AMP-responsive element. Gel retardation assays demonstrated that although the binding activity to the CCAAT site at - 140 was essentially the same as that in extracts from L-cells, hepatoma cells and rat livers, substantially greater amounts and different patterns of binding to the adjacent cyclic AMP-responsive element were observed in the extracts from the expressing L-cells and rat livers compared with those in the nonexpressing hepatoma cell nuclear extracts. Furthermore, mutagenesis of the cyclic AMP-responsive element site dramatically reduced promoter activity in transient transfection assays. The cyclic AMP-responsive element at position -160 appears to play an important role in the constitutive expression of the rat fibronectin gene. (Hepatology 1993;17:882-890.)
Defenestration of the sinusoidal endothelial cell in a rat model of cirrhosis
Authors: Mori Takashi , Okanoue Takeshi , Sawa Yoshihiko , Hori Naoki , Ohta Masaharu , Kagawa Keizo
Published: March 2007

We characterized the structural and immunohistological changes of sinusoidal endothelial cells that occur during cirrhosis in rats made cirrhotic with thioacetamide. Thioacetamide (200 mg/kg body wt) was injected intraperitoneally three times a week into male Wistar rats. Two, 4, 6 and 12 wk later, rat livers were observed under transmission and scanning electron microscopy and regular microscopy and immunostained with laminin and von Willebrand factor (factor VIII-related antigen) antibodies. The diameters and numbers of sinusoidal endothelial fenestrations did not change significantly after 2 wk in the thioacetamide-treated rats; however, they decreased within 4 wk after thioacetamide treatment. A basement membranelike structure in Disse's space was noted 6 wk after thioacetamide treatment. Laminin was detected in Disse's space after 4 wk. In vitro, in cultured sinusoidal endothelial cells, the diameter of sinusoidal endothelial fenestrations was significantly lower at 6 wk in thioacetamide-treated rats. von Willebrand factor was detected in the cytoplasm as granular fluorescence after 6 wk of thioacetamide treatment. These results suggest that as fibrosis develops in cirrhosis, the structural and immunohistochemical characteristics of sinusoidal endothelial cells change. (Hepatology 1993;17:891-897.)
Functional inactivation of neutrophils with a Mac-1 (CD11b/CD18) monoclonal antibody protects against ischemia-reperfusion injury in rat liver
Authors: Jaeschke Hartmut , Farhood Anwar , Bautista Abraham P. , Spolarics Zoltan , Spitzer John J. , Smith Wayne C.
Published: March 2007

The role of neutrophil CD11b/CD18 (Mac-1) adhesion proteins in the pathogenesis of hepatic reperfusion injury was investigated in an experimental model. Male Fischer rats were treated with a CD11b monoclonal antibody or an isotype-matched IgM control antibody and subjected to 45 min of hepatic ischemia followed by 24 hr of reperfusion. Large numbers of neutrophils were present in postischemic liver lobes (1,241 ± 64 polymorphonuclear cells/50 high-power fields) compared with numbers in baseline measurements (14 ± 3 polymorphonuclear cells/50 high-power fields), and severe liver injury was observed after 24 hr of reperfusion (hepatic necrosis: 88% ± 2%). Pretreatment with the CD11b antibody (two doses of 2 mg/kg each) significantly attenuated liver injury and reduced the number of polymorphonuclear cells in the postischemic liver by 59%. Selective treatment with the antibody only during reperfusion was similarly effective. The increased spontaneous superoxide formation of neutrophils isolated from postischemic liver (1.05 ± 0.11 nmol O2
−/hr/106 cells) was reduced by 56% in neutrophils from CD11b antibody-treated animals. Flow cytometric analysis of CD11b/CD18 expression on circulating neutrophils demonstrated significant upregulation at all time points during reperfusion. Clone 17 also effectively inhibited neutrophil extravasation in a glycogen peritonitis model. Our data are consistent with a dual protective effect of the CD11b antibody in hepatic reperfusion injury in vivo (i.e., reduced accumulation of neutrophils and their functional inactivation). (Hepatology 1993;17:915-923.)
Monoclonal antibody against the CD18 adhesion molecule stimulates glucose uptake by the liver and hepatic nonparenchymal cells
Authors: Bautista Abraham P. , Spolarics Zoltan , Jaeschke Hartmut , Smith Wayne C. , Spitzer John J.
Published: March 2007

Neutrophils and macrophages play an important role in the body's microbicidal defense and have been implicated in the induction of tissue injury in reperfusion, endotoxemia and septic shock. Cellular host defense is accompanied by enhanced glucose use. In this study we examined the effect of monoclonal antibody 1F12 on in vivo glucose use by selected tissues and hepatic phagocytes. Monoclonal antibody 1F12 is specific for the CD18 adhesion molecule on rat neutrophils and is the only known antibody that induces profound neutropenia. The administration of monoclonal antibody 1F12 at a final dose of 2 mg/kg body weight enhanced the removal of neutrophils from the circulation within 15 min. Leukopenia was sustained for 24 hr. Large numbers of neutrophils were sequestered in the liver at 4 hr. Although the number of neutrophils in the liver at 24 hr after antibody treatment was lower than at 4 hr, these values were still higher than those in the saline controls. The rate of glucose metabolism by selected tissues was not significantly altered by the antibody, except by the liver, in which use increased 2.7-fold vs. the control value at 4 hr after treatment. Hepatocytes, endothelial cells and Kupffer cells contributed to the increase in the rate of glucose metabolism by the liver. The rate of glucose metabolism by Kupffer cells was significantly elevated at 4 and 24 hr, whereas the rate of glucose metabolism of hepatocytes and endothelial cells returned to normal at 24 hr. After antibody treatment, the glucose uptake by hepatic sequestered neutrophils was significantly reduced at 4 hr and returned to near-normal levels at 24 hr. Another CD18 monoclonal antibody (monoclonal antibody WT.3), which does not cause neutropenia, did not alter the glucose uptake by tissues and hepatic cells, although it induced slight sequestration of neutrophils in the liver. The N-formylmet-leu-phe-induced superoxide release by neutrophils was attenuated by monoclonal antibody 1F12 in vitro and in vivo. These data indicate that as a consequence of monoclonal antibody 1F12 treatment, a major portion of the neutrophil pool is found in the liver and that Kupffer cells and endothelial cells become activated. It is postulated that this is part of the mechanism for increased clearance of effete leukocytes from the circulation. (Hepatology 1993;17:924-931.)
Mixed chimerism after transplantation: Mechanism or marker of specific tolerance?
Authors: Judge Thomas
Published: March 2007

We have previously reported data from clinical and laboratory animal observations which suggest that organ tolerance after transplantation depends on a state of balanced lymphodendritic cell chimerism between the host and donor graft. We have sought further evidence to support this hypothesis by investigating HLA-mismatched liver allograft recipients.

Nine of nine female recipients of livers from male donors had chimerism in their allografts and extrahepatic tissues, according to in-situ hybridisation and molecular techniques 10 to 19 years post-transplantation. In 8 women with good graft function, evidence of the Y chromosome was found in the blood (6/8), skin (8/8), and lymph nodes (7/8). A ninth patient whose transplant failed after 12 years from recurrent chronic viral hepatitis had chimerism in her lymph nodes, skin, jejunum, and aorta at the time of retransplantation.

Although cell migration is thought to take place after all types of transplantation, the large population of migratory cells in, and the extent of their seeding from, hepatic grafts may explain the privileged tolerogenicity of the liver compared with other organs.