bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver contains heparin-binding growth factors as the major growth factor for cultured fibroblasts
Authors: Nagasaki Takayuki , Lieberman Michael A.
Published: March 2007

The presence of heparin-binding growth factors in liver was investigated by measuring the DNA synthesis stimulatory activity of liver extracts using quiescent fibroblasts as target cells. It was found that cytosolic fractions of mouse, rat and human liver, as well as isolated rat hepatocytes, contain a large amount of growth stimulatory activity. Most liver cytosolic activity is due to heparin-binding growth factors, because > 90% of the activity bound to a heparin affinity column in the presence of 0.8 mol/L NaCl, and was quantitatively eluted with 2 mol/L NaCl. Purification of these factors from both mouse and rat liver indicated the presence of both heparin-binding growth factor-1 and 2 in liver extracts. The level of the heparin-binding growth factors, as estimated from the biological activity, is approximately 1 μg/gm mouse liver and 0.1 μg/gm rat and human liver. Heparin-binding growth factor-1-like factors were 10 times as abundant as heparin-binding growth factor-2-like factors. These data indicate that the cytosolic fractions of mouse, rat and human liver contain heparin-binding growth factors as the primary growth factor for fibroblasts, and heparin binding growth factor-1-like molecules account for most of the cytosolic activity in both mouse and rat liver. (HEPATOLOGY 1991;13:6-14).
Localization of epidermal growth factor receptor in hepatocyte nuclei
Authors: Marti Ulrich , Burwen Susan Jo , Wells Alan , Barker Mary E. , Huling Sandra , Feren Anna M. , Jones Albert L.
Published: March 2007

Experiments undertaken to investigate the binding of epidermal growth factor by hepatocyte nuclei showed that: (a) isolated nuclei from both normal and regenerating rat liver are capable of binding 125I-epidermal growth factor, (b) the nuclear epidermal growth factor-binding protein is similar in molecular weight to the plasma membrane epidermal growth factor receptor, (c) monoclonal antibodies produced against the plasma membrane epidermal growth factor receptor recognize the nuclear epidermal growth factor receptor and (d) the nuclear receptor has an affinity for epidermal growth factor comparable to that of the plasma membrane receptor, but fewer (˜ 10%) nuclear receptors are available per protein unit compared with the plasma membrane. (HEPATOLOGY 1991;13:15-20).
Expression of specific UDP-glucuronosyltransferase isoforms in carcinogen-induced preneoplastic rat liver nodules
Authors: Chowdhury Namita Roy , Saber Mohamed A. , Lahiri Pulak , Mackenzie Peter I. , Novikoff Phyllis M. , Becker Frederick F. , Chowdhury Jayanta Roy
Published: March 2007

The expression of specific UDP-glucuronosyltransferase isoforms in 2-acetylaminofluorane—induced rat liver preneoplastic nodules was studied; livers from pair-fed littermates were used as controls. For comparison, liver and kidney from 3-methylcholanthrene—treated or untreated (control) rats were used. Steadystate UDP-glucuronosyltransferase mRNA levels were determined by Northern blot analysis or in situ hybridization of tissue sections using a 30-mer oligonucleotide specific for the 3-methylcholanthrene—inducible UDP-glucuronosyltransferase (which is active toward 4-nitrophenol) or a double-stranded cDNA probe specific for androsterone—UDP-glucuronosyltransferase. For 3-methylcholanthrene—inducible UDP-glucurono-syltransferase, the mRNA level was very low in control liver; there was a 15-fold increase after 3-methylcholanthrene treatment. This mRNA was present at relatively high concentration in the kidney and there was a threefold increase after 3-methylcholanthrene administration. In livers with preneoplastic nodules 1 mo after cessation of carcinogen administration, this mRNA concentration was approximately 15 times greater than in control liver. Similar changes in the level of the 3-methylcholanthrene—inducible UDP-glucuronosyltransferase were also observed by in situ hybridization of tissue sections. Immunocytochemical studies using an antiserum that recognizes the 3-methylcholanthrene-inducible UDP-glucuronosyltransferase showed a marked increase in the concentration of this isoform in preneoplastic nodules compared with the adjacent nonnodular liver. Consistent with the changes in mRNA levels, there was a threefold increase in 4-nitrophenol-UDP-glucuronosyltransferase activity in 3-methylcholanthrene-treated rat livers and in livers with preneoplastic nodules. In contrast to the 3-methyl-cholanthrene-inducible UDP-glucuronosyltransferase mRNA, the androsterone-UDP-glucuronosyltransferase mRNA was abundant in the liver and nearly absent in the kidney; its concentration was not increased after 3-methylcholanthrene administration or in preneoplastic nodules. Immunocytochemical studies using an antiserum that recognizes androsterone- testosterone- and bilirubin-UDP-glucuronosyltransferase isoforms did not show any increase of the concentration of these antigens in preneoplastic nodules. Similarly, activities for androsterone, testosterone and bilirubin also did not increase after 3-methylcholanthrene administration or in livers bearing the preneoplastic nodules. (HEPATOLOGY 1991;13:38—46).
Kupffer cell activation and endothelial cell damage after storage of rat livers: Effects of reperfusion
Authors: Caldwell-Kenkel Jane C. , Currin Robert T. , Tanaka Yukio , Thurman Ronald G. , Lemasters John J.
Published: March 2007

Reperfusion injury characterized by loss of endothelial cell viability occurs after cold ischemic storage of livers for transplantation surgery. Here, ultrastructural changes in stored rat livers were examined by scanning and transmission electron microscopy. With increasing times of storage in Euro-Collins solution (4 to 24 hr) followed by 15 min of reperfusion at 37° C, a sequence of structural alterations was observed involving endothelial and Kupffer cells. Widening of endothelial fenestrations occurred after 4 hr and progressed over 8 to 24 hr to retraction of cellular processes, ball-like rounding, sinusoidal denudation and ultrastructural derangements consistent with loss of cell viability. Kupffer cells exhibited progressive rounding, ruffling of the cell surface, polarization, appearance of wormlike densities, vacuolization and degranulation over a similar time course. By contrast, the structures of parenchymal and fat-storing cells were relatively undisturbed by cold storage and reperfusion. Alterations to endothelial and Kupffer cells were also studied as a function of time of reperfusion. After 24 hr of storage, endothelial cells showed retraction of cytoplasm before reperfusion that progressed quickly to loss of viability and denudation during reperfusion. Kupffer cell activation (ruffling, degranulation) during reperfusion was slower and occurred after deterioration of endothelial cells. Livers stored in Euro-Collins solution were also compared with livers stored in University of Wisconsin cold storage solution, an improved preservation medium for transplantation. University of Wisconsin solution provided better preservation of endothelial structure and markedly reduced parenchymal cell blebbing and swelling before reperfusion. University of Wisconsin solution also reduced Kupffer cell activation and release of lysosomal enzymes. In conclusion, endothelial cell deterioration followed by Kupffer cell activation occurred after increasing times of cold ischemic storage and reperfusion of rat livers. Both changes may contribute to the pathophysiology of graft failure caused by reperfusion-mediated storage injury. (Hepatology 1991;13:83-95).
Detection of hepatitis B virus DNA in paraffin-embedded liver tissues in chronic hepatitis B or non-A, non-B hepatitis using the polymerase chain reaction
Authors: Shindo Michiko , Okuno Tadao , Arai Ken , Matsumoto Masayuki , Takeda Makoto , Kashima Kei , Shimada Mamoru , Fujiwara Yoshiaki , Sokawa Yoshihiro
Published: March 2007

We developed a polymerase chain reaction assay for the direct detection of hepatitis B virus in paraffinembedded liver tissue and applied this assay to determine whether hepatitis B virus DNA exists in livers with chronic hepatitis non-A, non-B. Fifty five liver biopsy samples were studied: 11 from patients with HBeAg-positive chronic hepatitis (paraffin-embedded) and 44 from patients with chronic hepatitis non-A, non-B (21 paraffin-embedded 25 fresh frozen). Thirty three (75%) of the non-A, non-B cases were positive for hepatitis C virus antibodies. Approximately 1 to 10 ng of DNA was extracted from the paraffin-embedded tissue and amplified using oligonucleotide (23-mer) primers specific for the S gene (positions 261 to 692). The β-globin gene was used as an internal control for sensitivity because this is a single copy gene and allows for relative quantification. In each of the chronic hepatitis B livers, the expected 432-base-pair amplification product for hepatitis B virus DNA and β-globin gene product were both detected. On the other hand, in the 21 paraffin-embedded chronic hepatitis non-A, non-B livers, no hepatitis B virus DNA was detected, although β-globin gene was observed in all. Furthermore, in all 25 frozen non-A, non-B livers, β-globin gene was observed, but no hepatitis B virus band was seen. The limit of detection of hepatitis B virus DNA by this method was estimated to be one genomic copy of hepatitis B virus DNA per cell. Thus all patients with chronic hepatitis B, but no patients with clinically diagnosed non-A, non-B hepatitis, had hepatitis B virus DNA in liver at a level of or above one copy per hepatocyte. (Hepatology 1991;13:167-171).
Detection of hepatitis C viral RNA by the polymerase chain reaction
Authors: Lucey Michael , Traber Peter G.
Published: March 2007

These studies used the polymerase chain reaction (PCR) to identify hepatitis C virus (HCV) RNA in clinical samples collected from patients with chronic liver disease or from blood donors. The relative role of this assay compared with detection of HCV antibodies in serum was evaluated. Weiner and colleagues found that 9 of 15 patients with non-A, non-B (NANB) chronic hepatitis and the only patient with cryptogenic cirrhosis had persistent antibodies to a nonstructural protein of HCV (C100-3). Seven of the 10 antibody-positive patients had HCV RNA detected by a highly sensitive PCR assay; two of the antibody-negative patients also had HCV RNA. The pattern of viral RNA and antibody was evaluated in one patient with acute posttransfusion NANB hepatitis (PTNANB) and in three chimpanzees with acute infection. Viral RNA was detected early after infection and, in each case, before the appearance of antibody. In one chimpanzee, viral RNA disappeared when antibody became detectable. The authors conclude that most patients with chronic NANB liver disease have HCV infection.

Garson and colleagues found that 6 of 1,100 donor blood units were repeatedly positive for antibodies to the C100-3 antigen (anti-C100-3). Only one of these six donor units was found to contain HCV RNA by a “nested PCR” assay. Nested PCR refers to the use of two successive rounds of amplification, with the second round using primers internal to, or nested within, the original two primers. The positive donor unit was the only one of the six antibody-positive units to cause posttransfusion hepatitis in a recipient. Sera from three other confirmed cases of posttransfusion hepatitis were evaluated and in each case one donor unit of blood was found to contain HCV RNA and anti-C100-3. The authors concluded that anti-C100-3 may not be a good predictor of infectivity in blood donors and that direct identification of viral RNA may be required.
Omeprazole and aryl hydrocarbon hydroxylases: Should we be worried?
Authors: Kolars J. C. , Turgeon D. K. , Watkins P. B.
Published: March 2007

Diaz and colleagues have carefully studied the effects of omeprazole on the expression of cytochrome P-450 in primary cultures of human hepatocytes. When omeprazole was added to the culture medium in varying concentrations, there was an increase in P-450IA2 protein and mRNA concentrations, an increase in de novo synthesis of P-450IA2 protein, and an increase in microsomal catalytic activities characteristic of P-450IA2 (phenacetin deethylase and acetanilide hydroxylase). Omeprazole treatment also resulted in an increase in both enzymatic activity characteristic of P-450IA1 (ethoxyresorufin deethylase and benzpyrene hydroxylase) and concentration of P-450IA1 mRNA. In contrast, omeprazole appeared to have no significant effect on expression of other P-450s within the P-450II or P-450III families in the hepatocytes. To validate these in vitro observations, liver biopsy specimens were obtained from five patients before and after a 4-day course of pharmacological doses of omeprazole. In each patient, omeprazole treatment appeared to result in a two- to eightfold increase in P-450IA2 immunoreactive protein and P-450IA1 and P-450IA2 enzymatic activities.

The authors conclude that omeprazole is an inducer of P-450IA2 and probably P-450IA1 in human liver. Induction of these enzymes could potentiate the bioactivation of carcinogens or the hepatotoxicity of some drugs such as acetaminophen.
Cholestasis and changes of portal pressure caused by chlorpromazine in the perfused rat liver
Authors: Akerboom Theodorus , Schneider Ingo , vom Dahl Stephan , Sies Helmut
Published: March 2007

Chlorpromazine (10 μmol/L) causes a marked increase in portal pressure in perfused rat liver. Simultaneously, oxygen consumption, hepatic clearance of taurocholate and bile flow are diminished. These effects are prevented by the cyclooxygenase inhibitors indomethacin (15 μmol/L), acetylsalicylate (3 mmol/L) or ibuprofen (200 μmol/L). On addition of chlorpromazine the liver releases increased amounts of prostaglandin D2; this increase does not occur in the presence of indomethacin.

At higher concentrations of chlorpromazine (100 μmol/L) the inhibition of taurocholate clearance and bile flow is accompanied by only a moderate increase of portal pressure, and indomethacin is without effect. At this high concentration, substantial cell damage, as indicated by the release of lactate dehydrogenase, is present.

We conclude that arachidonic acid—derived metabolites, notably prostanoids, are involved in the inhibition of bile flow and of taurocholate clearance observed at low concentrations of chlorpromazine. The data suggest that changes in the microcirculation are responsible for the impairment of the liver functions. At higher concentrations of chlorpromazine the cell toxicity of the drug becomes prominent. (Hepatology 1991;13:216-221).
Zonal differences in ethanol-induced impairments in receptor-mediated endocytosis of asialoglycoproteins in isolated rat hepatocytes
Authors: Casey Carol A. , Kragskow Sandra L. , Sorrell Michael F. , Tuma Dean J.
Published: March 2007

We have shown previously that ethanol-induced defects in receptor-mediated endocytosis of asialoorosomucoid occurred as early as 1 wk after ethanol feeding. This study was undertaken as an initial attempt to establish a possible role of defective receptormediated endocytosis in liver injury by investigating whether differences exist in the effects of ethanol on receptor-mediated endocytosis in hepatocytes isolated from different regions of the liver. Perivenule cells, present in the distal half of the liver, are thought to be more susceptible to ethanol-induced liver injury than are the periportal cells located in the proximal half of the liver acini. For these studies, we fed male Sprague-Dawley rats for 7 days with liquid diets containing either ethanol (36% of calories) or isocaloric carbohydrate. Perivenule and periportal hepatocytes were then isolated using a digitonin-collagenase perfusion method. In control animals, cells isolated from the perivenule region bound significantly more ligand than did cells from the periportal region. Amounts of ligand internalized and degraded were also greater in perivenule than in periportal cells in these animals. After ethanol feeding, cells isolated from both the perivenule and periportal regions bound significantly less ligand than their respective controls. This impairment in surface and total binding was more pronounced in perivenule than in periportal cells. Internalization and degradation of the ligand were also more adversely affected in the centrilobular region as shown by decreases of greater than 60% in perivenule cells and by only 20% to 30% in periportal cells of ethanol-fed animals compared with controls. Receptor recycling was impaired in the perivenule region by ethanol administration as shown by receptor cycle times that were significantly prolonged in cells from the perivenule region but were relatively unchanged in periportal cells. These results indicate that ethanolinduced impairments in receptor-mediated endocytosis are more dramatic in the perivenule region of the liver, thus suggesting a potential role of defective receptor-mediated endocytosis in ethanol-induced liver injury. (Hepatology 1991;13:260—266).
Hepatocellular phenotype in Vitro is influenced by biophysical features of the collagenous substratum
Authors: Lindblad William J. , Schuetz Erin G. , Redford Kaye S. , Guzelian Philip S.
Published: March 2007

Hepatocytes maintained on different substratain vitropossess strikingly different morphological and biochemical features. Rounded, multicellular aggregates of hepatocytes are seen if the cells are plated onto Matrigel, a reconstituted basement membrane, whereas a flattened, monolayer of hepatocytes is observed with Vitrogen. Hepatocellular protein synthesis is much greater on the Matrigel, although collagen biosynthesis appears selectively enhanced on Vitrogen-grown hepatocytes. We determined that denatured type I collagen could be substituted for Matrigel as the substratum, with the hepatocytes remaining the same both morphologically and biochemically. This suggested that the cells respond to the biophysical state of the extracellular matrix not only to protein sequences that determine a binding site. Measurement of steady-state messenger RNA levels within cells cultured onto different matrices indicated that the fluid substrata of either Matrigel or denatured type I collagen were facilitative for induction of cytochrome P-450b/e, which was not seen with the rigid type I collagen substrata. In contrast the messenger RNA level for the cytoskeletal protein actin was decreased on the fluid matrices, suggesting that the rounded cells had a lower requirement for this protein. These findings indicate that hepatocytes are responsive to the biophysical state of the extracellular matrix, which can lead to significant changes in gene expression by the cells. (Hepatology 1991;13:282-288).
Differences in glycolytic capacity and hypoxia tolerance between hepatoma cells and hepatocytes
Authors: Hugo-Wissemann Doris , Anundi Irene , Lauchart Werner , Viebahn Richard , de Groot Herbert
Published: March 2007

Viability, glycolytic capacity and energy metabolism under anaerobic conditions were studied in the hepatoma cell lines HTC, FU5 and HepG2 and in rat and human hepatocytes using glucose and fructose as glycolytic precursors. During 6 hr of anaerobic incubation without additional substrate, viability decreased rapidly in FU5 and HTC cells, whereas viability of HepG2 cells was not significantly affected. In all tumor cells, 10 mmol/L glucose prevented hypoxic cell injury almost completely. Lactate formation from glucose was about five times higher than in hepatocytes under these circumstances. ATP content of the tumor cells remained almost constant under anaerobic conditions in the presence of glucose. Ten millimoles per liter of fructose diminished glycolysis in the hepatoma cells compared with glucose, ranging from 87% reduction in HTC cells to 43% reduction in HepG2 cells. Accordingly, ATP content decreased rapidly in the FU5 and slowly in the HepG2 cells. Viability was strongly diminished in the HTC and FU5 cells in the presence of fructose, whereas in the HepG2 cells no effect of fructose on viability was detectable. In contrast to the hepatoma cells, rat and human hepatocytes exhibited higher rates of anaerobic glycolysis in the presence of fructose and thus were able to maintain their viability under these conditions. These differences in glycolytic capacity, energy metabolism and hypoxia tolerance of hepatoma cells compared with hepatocytes may be used for the treatment of liver cancer by isolated liver perfusion and ex situ revision of the organ. (Hepatology 1991;13:297-303).
Ultrastructural localization of interferon-producing cells in the livers of patients with chronic hepatitis B
Authors: Dienes Hans P. , Hess Georg , Wöorsdörfer Marita , Rossol Siegbert , Gallati Harald , Ramadori Giuliano , Büschenfelde Karl-Hermann Meyer Zum
Published: March 2007

Cells expressing α- and γ-interferon were localized in the liver tissue of patients with chronic hepatitis B by means of light and electron microscopy using monoclonal antibodies. Interferon-positive cells were regularly seen in the infiltrating mononuclear cells, and the number showed a good correlation with the degree of the necroinflammatory activity of the disease. In chronic persistent hepatitis and in normal livers, they were infrequent or virtually absent. α-Interferon was shown to be positive in lymphocytes, polymorphonuclear leukocytes and fibroblasts, Kupffer cells and, weakly, in the cytoplasm of a few hepatocytes in cases of active hepatitis, whereas γ-interferon was demonstrated only in lymphocytes. The expression of human leukocyte class I antigens on hepatocytes showed a close association with the number of interferonproducing cells, but not with the presence of virus particles and HBcAg in liver cells, when studied using electron microscopy and double-labeling.

Interferon seems to be an important regulator of the local immune response in the liver in patients with chronic hepatitis B. Its functions may play a role in inducing the human leukocyte class I antigen expression on hepatocytes, thus enhancing the elimination of virus-containing hepatocytes by major histocompatibility complex-restricted cytotoxic lymphocytes. (Hepatology 1991;13:321-326).
Molecular cloning and characterization of an isolate of hepatitis delta virus from Taiwan
Authors: Chao You-Chen , Lee Chuan-Mo , Tang Hung-Shang , Govindarajan Sugantha , Lai Michael M. C.
Published: March 2007

The genomic RNA of an Asian isolate of hepatitis delta virus was cloned from a Chinese patient from Taiwan, using the polymerase chain reaction to amplify cDNA for cloning and sequencing. The sequence of this hepatitis delta virus isolate shares an 86% to 88% similarity with the three published hepatitis delta virus RNA sequences, suggesting heterogeneity of hepatitis delta viruses from different geographical areas. Four highly conserved, long stretches of sequence were found. These four regions corresponded to the sequences required for the autocatalytic cleavage activities of the genomic and antigenomic RNAs and the middle and the carboxyl terminal parts of the open reading frame for the delta antigen on the antigenomic strand. The conservation of nucleotide sequence in these four regions was further confirmed by sequencing additional hepatitis delta virus RNAs obtained from three patients with chronic delta hepatitis who lived in Los Angeles. These findings suggest that the conserved sequences are critical for viral replication. These conserved regions offer ideal sites for primer selection to carry out polymerase chain reactions to detect hepatitis delta virus RNA in patients with hepatitis delta virus infection. (Hepatology 1991;13:345-352).
Pancreatic pseudocyst in the left hepatic lobe: A report of two cases
Authors: Okuda Kunjo , Sugita Shujiro , Tsukada Etsuo , Sakuma Yoichi , Ohkubo Keishi
Published: March 2007

The ultrasound and computed tomographic imaging features in a rare pancreatic pseudocyst of the liver are described in two patients. The pseudocysts occurred in the left lobe in both cases, one after a traumatic injury and the other after alcoholic pancreatitis. The possible topographical sequences with which pancreatic secretions entered the left hepatic lobe to form a cyst are discussed. (Hepatology 1991;13:359-363).
Antimicrosomal antibodies: What are they telling us?
Authors: Watkins Paul B.
Published: March 2007

Patients with dihydralazine hepatotoxicity have been found to have circulating autoantibodies that react with liver microsomes (anti-liver microsome antibodies) and that are clearly distinct from anti-liver and kidney microsomal antibodies observed in patients with tienilic acid-induced hepatitis and in some patients with autoimmune hepatitis. The authors show that anti-liver microsome antibodies present in the sera of five patients with dihydralazine-induced hepatitis specifically react on immunoblots with a 53 kD protein. They further conclude that this target antigen is the phase I drug metabolizing enzyme termed P-450IA2 based on the following observations: (a) immunoblots of a battery of human liver microsomes produced the identical pattern of relative staining whether the blots were developed with anti-rat P-450IA2 IgG, anti-human P-450IA2 IgG or each of the five patients' sera; (b) P-450IA2 catalytic activity was selectively inhibited when human liver microsomes were preincubated with anti-liver microsome-positive sera; (c) anti-liver microsome-positive sera identified purified human P-450IA2 on immunoblots. Anti-liver microsome antibodies appeared to be specific for dihydralazine hepatitis because they were not present in sera obtained from 28 other patients including patients receiving dihydralazine without a toxic response and patients with other significant liver diseases. Finally, the authors demonstrated that dihydralazine could competitively inhibit catalytic activity characteristic of P-450IA2 in human liver microsomes, suggesting that P-450IA2 may be involved in the metabolism of dihydralazine.
Hyposensitivity to vasopressin in patients with hepatitis B-related cirrhosis during acute variceal hemorrhage
Authors: Tsai Yang-Te , Lee Fa-Yauh , Lin Han-Chieh , Lee Shou-Dong , Hsia Hsiao-Chung , Lin Wen-Jeh , Wang Sun-Sang , Lay Chii-Shyan , Lai Kwok-Hung , Lo Kwang-Juei
Published: March 2007

It has been suggested that vasopressin given during hemorrhage may be less effective than when given during a stable state in a portal-hypertensive rat model. This study was designed to evaluate the hemodynamic response to vasopressin infusion in 25 HBsAgpositive cirrhotic patients. Nine patients had active variceal hemorrhage before vasopressin infusion, and the other 16 patients were in a stable condition at the time of infusion. The two groups of patients were similar in baseline values except that a higher heart rate was found in patients with hemorrhage (96 ± 20 vs. 73 ± 10 beats/min, mean ± S.D., p < 0.01). Thirty minutes after vasopressin infusion (0.66 units/min), hepatic venous pressure gradient significantly decreased in both bleeding and stable patients (from 21 ± 9 to 18 ± 9 mm Hg, p < 0.05; and from 18 ± 4 to 8 ± 3 mm Hg, p < 0.000 1, respectively). However, the decrease of hepatic venous pressure gradient was less obvious in bleeding patients as compared with stable patients (4 ± 3 vs. 9 ± 2 mm Hg, p < 0.0001). A significant reduction of hepatic venous pressure gradient after vasopressin infusion was found in five bleeding patients without shock (from a median of 16 mm Hg [range = 12 to 26] to 11 mm Hg [range = 6 to 18], p < 0.05), but not in four bleeding patients with shock (from 28 [range = 15 to 36] to 25 [range = 18 to 33] mm Hg, p > 0.05). Vasopressin infusion resulted in a significantly lower heart rate and cardiac output with a concomitantly higher systemic vascular resistance in both groups of patients (p < 0.05). Mean arterial pressure increased after vasopressin infusion in stable patients (p < 0.000 1), but it remained unchanged in bleeding patients (p > 0.05). These findings confirm that vasopressin given during acute variceal hemorrhage, especially in cirrhotic patients with shock, may be less effective than when given during a stable state. (Hepatology 1991;13:407-412.)
Expression of X protein and hepatitis B virus replication in chronic hepatitis
Authors: Haruna Yoshimichi , Hayashi Norio , Katayama Kazuhiro , Yuki Nobukabu , Kasahara Akinori , Sasaki Yutaka , Fusamoto Hideyuki , Kamada Takenobu
Published: March 2007

The X protein can act on the enhancer of hepatitis B virus in an in vitro system and elevate the transcriptional level of hepatitis B virus. However, because no relationship had been reported between X protein expression and hepatitis B virus replication in patients with chronic hepatitis B, we focused on its expression in the liver in comparison with markers of hepatitis B virus replication. Liver biopsy samples and sera from 59 carriers with HBsAg were examined immunohistochemically for X protein using rabbit IgG against recombinant X protein. There was a significant difference in the serum hepatitis B virus DNA level between X protein-positive and -negative patients (p < 0.001). Serum pre-S1 and pre-S2 antigens were also measured quantitatively by enzyme immunoassay using monoclonal antibodies specific against each antigen. The titers of pre-S1 antigen in patients positive for X protein were significantly higher (p < 0.001) than those of the X protein-negative patients (3.02 ± 0.99 vs. 2.00 ± 0.59, respectively). Similarly, the titers of pre-S2 antigen were 2.98 ± 0.91 vs. 1.94 ± 0.54, respectively (p < 0.001). The rate of positivity of the X protein was higher (38 of 49; 77.6%) in the replicative group (serum HBeAg, serum hepatitis B virus DNA or HBcAg in liver positive) compared with that observed in the nonreplicative group (3 of 10; 30% - serum HBeAg, serum hepatitis B virus DNA and HBcAg in liver negative) (p < 0.01). Our findings indicate that the X protein is closely correlated with hepatitis B virus replication and may have an important role in viral replication in chronic hepatitis B virus infection. (Hepatology 1991;13:417-421.)
Increased lysophosphatidylcholine and pancreatic enzyme content in bile of patients with anomalous pancreaticobiliary ductal junction
Authors: Shimada Kazuo , Yanagisawa Jiro , Nakayama Fumio
Published: March 2007

A high incidence of inflammation and carcinoma of the biliary tract in patients with anomalous pancreaticobiliary ductal junction has been well documented. The change in biliary phospholipids as a result of the reflux of pancreatic juice into the biliary tract through anomalous pancreaticobiliary ductal junction may be responsible for it. We developed a new method of analysis of phospholipid classes using aminopropyl Bond Elut cartridge for extraction and highperformance liquid chromatography for separation. Satisfactory recovery was achieved (i.e., more than 95% for both phosphatidylcholine and lysophosphatidylcholine). With this method, the bile of 11 patients with anomalous pancreaticobiliary ductal junction was examined. The concentration and proportion of lysophosphatidylcholine in bile were much higher in the presence of anomalous pancreaticobiliary ductal junction than in controls (3.44 ± 1.50 mmol/L vs. 0.52 ± 0.25 mmol/L, 60.0% ± 31.0% vs. 2.3% ± 1.4% in gallbladder bile; p <0.001). In contrast, the concentration of phosphatidylcholine and the sum of phosphatidylcholine and lysophosphatidylcholine in gallbladder bile significantly decreased (p <0.001), but in hepatic bile they did not. An inverse correlation was found between the proportion of lysophosphatidylcholine and phospholipid concentration in gallbladder bile. Phospholipase A2 and amylase activities in bile were markedly high. Increased total fatty acid concentration and proportion of unsaturated fatty acid in bile were found. Total bile acid concentration in gallbladder bile was significantly lower than in controls. These results suggest that a considerable amount of lysophosphatidylcholine, which is known to have a cytotoxic effect, is produced by phospholipase A2 in refluxing pancreatic juice, and an increased concentration of lysophosphatidylcholine gives rise to cell damage causing mucosal hyperplasia and metaplasia. This condition may be one of the factors responsible for the occurrence of carcinoma of the biliary tract. (Hepatology 1991;13:s438-444.)
The role of methanethiol in the pathogenesis of hepatic encephalopathy
Authors: Blom Henk J. , Ferenci Peter , Grimm Georg , Yap Sing H. , Tangerman Albert
Published: March 2007

Mixed disulfides of methanethiol represent a relative estimate for an exposure to methanethiol. The concentrations of methanethiol-mixed disulfides, methionine, 4-methylthio-2-oxobutyrate and ammonia were measured in patients with different stages of hepatic encephalopathy, in patients with chronic kidney failure and in healthy subjects. In patients with hepatic encephalopathy, the mean serum concentrations of all these compounds were elevated. However, the elevations of methanethiol-mixed disulfides were small and partly caused by decreased renal function. In addition, the levels of methanethiol-mixed disulfides did not differ significantly between the different grades of hepatic encephalopathy. The concentrations of methanethiol-mixed disulfides were substantially lower than those previously observed in healthy subjects after an oral methionine load or in a patient with a deficiency in methionine adenosyltransferase, the latter without causing encephalopathy. We concluded that the role of methanethiol in the pathogenesis of hepatic encephalopathy is probably minor, if not insignificant.

In the patients with hepatic encephalopathy, a significant correlation was found between the concentrations of methionine and 4-methylthio-2-oxobutyrate and between 4-methylthio-2-oxobutyrate and methanethiol-mixed disulfides, supporting the theory that methanethiol is formed by way of the methionine transamination pathway. Evidence is provided that, besides the methionine transsulfuration pathway, the transamination pathway is also impaired in patients with hepatic encephalopathy. (Hepatology 1991;13:445-454.)
Proton accumulation and ATPase activity in Golgi apparatus-enriched vesicles from rat liver
Authors: Yeh Horng-I , Van Rossum G. D. V.
Published: March 2007

We have studied the mechanism by which liver Golgi apparatus maintains the acidity of its contents, using a subcellular fraction from rat liver highly enriched in Golgi marker enzymes. Proton accumulation (measured by quenching of acridine-orange fluorescence) and anion-dependent ATPase were characterized and compared. Maximal ATPase and proton accumulation required ATP; GTP and other nucleotides gave 10% to 30% of maximal activity. Among anions, Cl− and Br− approximately doubled the activities; others were much less effective. Half-maximal increase of ATPase and H uptake required 55 mmol/L and 27 mmol/L Cl−, respectively. In predominantly chloride media, SCN− and NO3
− markedly inhibited H+ uptake. Nitrate competitively inhibited both the chloride-dependent ATPase (apparent Ki 6 mmol/L) and proton uptake (apparent Ki 2 mmol/L). Nitrate and SCN− also inhabited uptake of 36Cl. Replacing K+ with Na+ had no effect on the initial rate of proton uptake but somewhat reduced the steady state attained. Replacement of K+ with NH4
+ and choline reduced proton uptake without affecting ATPase. The ATPase and H+ uptake were supported equally well by Mg2+ or Mn2+. The ATPase was competitively inhibited by 4-acetamido-4′-isothiocyano-stilbene-2,2′-disulfonic acid (apparent Ki 39 μmol/L). Other agents inhibiting both H+ uptake and ATPase were N-ethylmaleimide, N,N′-dicyclohexylcarbodiimide, chlorpromazine, diethylstilbestrol, Zn2+, Co2+ and Cu2+. In the Cl− medium, accumulated protons were released by ionophores at the relative rates, monensin = nigericin > valinomycin > carbonyl cyanide mchlorophenylhydrazone; the last of these also reduced ATPase activity. In the absence of Cl−, monensin and valinomycin both stimulated the ATPase. These results show a close association between ATPase activity and acidification of liver Golgi vesicles. They support a role for Cl− that depends on its uptake as a counter ion for H+ and suggest that it may also stimulate proton transport by a more direct effect on a component of the transport system. (Hepatology 1991;13:523-533.)
Rapid induction of hepatic fibrosis in the gerbil after the parenteral administration of iron-dextran complex
Authors: Carthew Philip , Edwards Richard E. , Smith Andrew G. , Dorman Barbara , Francis Jean E.
Published: March 2007

The parenteral administration of iron-dextran complex to gerbils caused hepatic hemosiderosis and fibrosis after 6 wk. Type I and III collagen synthesis in the liver developed from perisinusoidal stellate cells that are often referred to as myofibroblasts. Immunohistologically these cells were shown to have large intracellular deposits of ferritin. The hepatic fibrosis appeared to be associated with aggregates of these cells rather than the aggregates of Kupffer cells, which also occur in hemosiderosis in the liver. No appreciable necrosis of hepatocytes to trigger the fibrotic response was found, so that the fibrosis appeared to be related to the accumulation of ferritin in the perisinusoidal stellate cells. In contrast, rats and mice did not accumulate ferritin in their perisinusoidal cells or develop hepatic fibrosis in response to parenterally administered iron, although they accumulated similar or greater amounts of total iron in their livers. The rapid induction of hepatic fibrosis in gerbils in response to parenterally administered iron will provide a model to investigate the mechanism of induction of collagen deposition in response to iron overload and a means of quickly evaluating therapeutic treatments for iron overload-induced fibrosis in vivo using iron-chelating drugs. (Hepatology 1991;13:534-539.)
Fish oil protects mice against acetaminophen hepatotoxicity in vivo
Authors: Speck Robert F. , Lauterburg Bernhard H.
Published: March 2007

Recent observations suggest that products of nonparenchymal liver cells such as eicosanoids and cytokines might play a role in the expression of liver injury after administration of acetaminophen and other noxious agents. We therefore investigated the effect of a fish oil diet, which results in the generation of eicosanoids with altered biological properties and suppresses the production of certain cytokines on acetaminophen hepatotoxicity. Mice were fed a diet with either 20% fish oil containing n-3 fatty acids or 20% olive oil containing n-6 fatty acids for 2 wk. Cytochrome P-450 activity and the concentration of glutathione were similar in the two groups before acetaminophen administration. Nevertheless, 24 hr after the administration of 375 mg/kg acetaminophen intraperitoneally, the extent of centrilobular necrosis and the activity of ALT in plasma were significantly lower in the n-3 fatty acid group (median = 277 vs. 3,367 IU/L; p < 0.001). In the n-3 fatty acid group covalent binding of the drug to liver proteins (0.19 ± 0.03 vs. 0.67 ± 0.07 nmol/mg protein; p < 0.01) and the median plasma concentration of acetaminophen (0.1 vs. 0.6 mmol/L) were significantly lower 3 hr after dosing. Mice fed the n-3 fatty acid diet excreted less acetaminophen sulfate but significantly more acetaminophen glucuronide in 24 hr. Thus the major protective effect of the fish oil diet appears to be an increased clearance of acetaminophen resulting from a stimulation of the glucuronidation of acetaminophen, which may be due to the fluidization of microsomal membranes by fish oil. (Hepatology 1991;13:557-561.)
Hyperdynamic circulation in a chronic murine schistosomiasis model of portal hypertension
Authors: Sarin Shiv K. , Mosca Piergiorgio , Sabbà Carlo , Groszmann Roberto J.
Published: March 2007

Chronic murine schistosomiasis is a natural disease model of portal hypertension closely mimicking the clinical and histological features of human hepatic schistosomiasis. We studied the splanchnic and systemic hemodynamics in the murine model of schistosomiasis by radioactive microsphere technique. Mice infected with 60 cercariae of Schistosoma mansoni (n = 8) were studied hemodynamically 11 wk after the infection and were compared with age-matched healthy controls (n = 11). Mean portal venous inflow in the infected mice (3.82 ± 0.32 ml/min) was 61% higher than in the healthy animals (2.37 ± 0.25 ml/min; p < 0.01). A twofold increase in hepatic arterial flow was also seen in mice with schistosomiasis (0.47 ± 0.14 ml/min) as compared with controls (0.16 ± 0.03 ml/min; p < 0.05), whereas splanchnic arteriolar resistance (60.91 ± 7.64 vs. 101.21 ± 11.06 mm Hg · min · ml−1. gm; p < 0.05) and peripheral vascular resistance (112.05 ± 14.05 vs 254.53 ± 29.86 mm Hg · min ml−1 · gm; p < 0.01) were reduced. There was a significant increase in cardiac index (752 ± 99 vs. 453 ± 55 ml · min−1 · kg body weight−1; p < 0.05) and reduction in mean arterial pressure (81.37 ± 3.09 vs. 101.45 ± 5.85 mm Hg; p < 0.05) in the infected animals compared with controls. These observations clearly demonstrate the existence of a hyperdynamic circulatory state in this model of portal hypertension. (Hepatology 1991;13:581-584.)
Acetaldehyde increases procollagen type I and fibronectin gene transcription in cultured rat fat-storing cells through a protein synthesis-dependent mechanism
Authors: Casini Alessandro , Cunningham Mike , Rojkind Marcos , Lieber Charles S.
Published: March 2007

We previously reported that acetaldehyde increases the production of type I collagen in cultured rat fat-storing cells. We studied the regulation of this effect by determining the expression of procollagen type I, fibronectin and transforming growth factor-β1 messenger RNAs in passage 1 and 2 cultures of fatstoring cells exposed to acetaldehyde for up to 24 hr. By 6 hr, acetaldehyde increased the steady-state levels of α1 procollagen type I messenger RNA 3.2-fold and of fibronectin messenger RNA 2.8-fold above control values. At 24 hr, messenger RNA levels remained elevated. In contrast, transforming growth factor-β1 messenger RNA steady-state levels remained unaltered by 6 hr, but increased 1.5-fold by 24 hr. Cycloheximide (0.3 mmol/L) completely inhibited the acetaldehyde effect when added at zero time but was less effective when added at 15 min. The effect of acetaldehyde was not modified when cells were cultured in the presence of the acetaldehyde dehydrogenase inhibitor cyanamide (100 μmol/L). Fat-storing cells were also cultured in the presence of lactate (5, 15 and 25 mmol/L) for 6 hr. At none of these concentrations was any effect seen on either α1(I) procollagen or fibronectin messenger RNAs. In the presence of methylene blue, a scavenger of reducing equivalents, the effect of acetaldehyde on α1(I) procollagen and fibronectin gene expression was totally inhibited. Transcription run-on assay showed that acetaldehyde increased both procollagen type I and fibronectin transcriptional activity threefold and 2.5-fold, respectively. We conclude that acetaldehyde increases α1(I) procollagen and fibronectin gene expression through enhanced transcription by a mechanism dependent on newly synthesized proteins. Our data suggest that this effect requires no further metabolism of acetaldehyde, but is possibly caused by adduct formation. (Hepatology 1991;13:758-765.)
Effect of cyclosporine on hepatic energy status and on fructose metabolism after portacaval shunt in dog as monitored by phosphorus-31 nuclear magnetic resonance spectroscopy in vivo
Authors: Rossaro Lorenzo , Mazzaferro Vincenzo , Scotti-Foglieni Carlo L. , Williams Donald S. , Simplaceanu Elena , Simplaceanu Virgil , Francavilla Antonio , Starzl Thomas E. , Ho Chien , Van Thiel David H.
Published: March 2007

The effect of cyclosporin A on the hepatic energy status and intracellular pH of the liver and its response to a fructose challenge has been investigated using in vivo phosphorus-31 nuclear magnetic resonance spectroscopy in dogs. Three experimental groups were studied: (a) control dogs (n = 5), (b) dogs 4 days after the creation of an end-to-side portacaval shunt (n = 5), and (c) dogs 4 days after portacaval shunt and continuous infusion of cyclosporin A (4 mg/kg/day) by way of the left portal vein (portacaval shunt plus cyclosporin A, n = 5). The phosphorus-31 nuclear magnetic resonance spectra were obtained at 81 MHz using a Bruker BIOSPEC II 4.7-tesla nuclear magnetic resonance system equipped with a 40-cm horizontal bore superconducting solenoid. The phosphomonoesters (p < 0.01), inorganic phosphate and ATP levels (p < 0.05) were decreased significantly in portacaval shunt-treated and in portacaval shunt-pluscyclosporin A-treated dogs compared with unshunted control dogs. After a fructose challenge (750 mg/kg body wt, intravenously), fructose-1-phosphate metabolism was reduced in portacaval shunt-treated dogs compared with either the normal or portacaval shuntplus-cyclosporin A-treated dogs (p < 0.05). Both portacaval shunt- and portacaval shunt-plus-cyclosporin A-treated dogs demonstrated a reduced decline in ATP levels after fructose infusion when compared with the controls (p < 0.05). Immediately after the fructose challenge, the intracellular pH decreased from 7.30 ± 0.03 to 7.00 ± 0.05 in all animals (p < 0.01) and then gradually returned to normal over 60 min. These data, obtained in vivo using phosphorus-31 nuclear magnetic resonance spectroscopy of the liver after a portacaval shunt, suggest that: (a) the energy status of the liver is reduced in dogs with a portacaval shunt compared with that of normal controls and (b) cyclosporin A treatment ameliorates the reduction in hepatic metabolism normally observed after a fructose challenge to the liver with a portacaval shunt. (Hepatology 1991;13:780-785.)
Localizing glucose transport proteins: Active investigation of passive carriers
Authors: Gumucio Jorge J. , Kaunitz Jonathan D.
Published: March 2007

The “liver” isoform of the facilitated diffusion glucose transporter is expressed predominantly in liver, intestine, kidney, and pancreatic islet α-cells. The apparent molecular mass of the transporter in liver, kidney, and intestine is different, as detected by Western blot analysis of membrane proteins using antipeptide antibodies. However, as assessed by Northern blot analysis and molecular cloning, the same mRNA is expressed in these tissues, indicating that there are tissue-specific posttranslational modifications of the same transporter polypeptide. As determined by immunofluorescence analysis on frozen tissue sections, the liver glucose transporter is present on the sinusoidal membrane of hepatocytes, on the basolateral membrane of fully differentiated absorptive intestine epithelial cells, and on the basolateral membrane of proximal tubule cells of the kidney nephron. This localization is consistent with the involvement of the liver glucose transporter in several key steps of glucose metabolism: glucose uptake and release by the liver and absorption or reabsorption by epithelial cells of the intestine and kidney, respectively.

The localization of two glucose transporter isoforms was mapped in the rat kidney: the high-Michaelis constant (Km; 15-20mM) low-affinity “liver” transporter and the low-Km (1-2mM) high-affinity erythroid/brain transporter. Both are basolateral membrane proteins, but the liver transporter was present exclusively in the S1 part of the proximal tubule, whereas the erythroid/brain transporter was expressed at variable levels in different nephron segments. Staining intensity was low in the straight proximal tubule (S3), intermediate in the medullary thin and thick ascending limbs, and highest in connecting segments and collecting ducts. In the collecting duct, the erythroid/brain glucose transporter was expressed at the highest level in intercalated cells; less was present in principal cells. In the papilla, only intercalated cells expressed this transporter isoform. These results suggest specific involvement of each transporter isoform in transepithelial glucose reabsorption by different segments of the proximal tubule. They also indicate that while the liver glucose transporter is present in gluconeogenic cells, there is a good correlation between the level of expression of the erythroid/brain glucose transporter and the glycolytic activity of the different nephron segments.