Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 56
Filter
Add more filters










Publication year range
1.
Aliment Pharmacol Ther ; 30(4): 343-51, 2009 Aug 15.
Article in English | MEDLINE | ID: mdl-19485982

ABSTRACT

BACKGROUND: The benefits of prolonging peginterferon and ribavirin after 48 weeks of treatment to maximize sustained virological responses (SVR) in hepatitis C virus (HCV) genotype 1-infected patients remain to be understood. AIM: To investigate whether extended treatment longer than 72 weeks may be superior to 72-week treatment. METHODS: A total of 120 treatment-naïve or retreated patients with HCV genotype 1 were treated with peginterferon-alpha-2b (1.5 microg/kg/week) plus weight-based ribavirin. We had 34 late responders, in whom HCV RNA first became undetectable at week 12-48, and randomized them into three groups receiving standard-dose peginterferon-alpha-2b plus low-dose ribavirin (200 mg/day) for extended 24 weeks (group A), receiving low-dose peginterferon-alpha-2b (0.75 microg/kg/week) plus low-dose ribavirin for extended 48 weeks (group B) or no extended treatment (group C), and evaluated the outcome according to their virological response. RESULTS: Multivariate analysis showed that the treatment for 96 weeks was identified as a significant, independent factor associated with SVR in HCV genotype 1-infected late responders in comparison with group A [odds ratio (OR), 10.002; P = 0.080] and group C (OR, 17.748; P = 0.025). CONCLUSION: Extending the treatment duration from 48 weeks to 96 weeks improves SVR rates in genotype 1-infected patients with late virological response to peginterferon-alpha-2b and ribavirin.


Subject(s)
Antiviral Agents/administration & dosage , Hepatitis C, Chronic/drug therapy , Interferon-alpha/administration & dosage , Polyethylene Glycols/administration & dosage , Ribavirin/administration & dosage , Adult , Aged , Analysis of Variance , Drug Therapy, Combination , Female , Genotype , Hepacivirus/genetics , Hepatitis C, Chronic/genetics , Hepatitis C, Chronic/virology , Humans , Interferon alpha-2 , Male , Middle Aged , Recombinant Proteins , Time Factors , Treatment Outcome
2.
Liver ; 21(5): 309-19, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11589767

ABSTRACT

BACKGROUND/AIMS: To clarify the mechanism of hepatocyte apoptosis induced by tumor necrosis factor-alpha (TNF-alpha), caspase cascade and ceramide formation were investigated in the liver of D-galactosamine (GalN)-sensitized mice treated with TNF-alpha. METHODS: Seven-week-old male BALB/c mice were intraperitoneally injected with 20 mg GalN 30 min prior to the intravenous injection of recombinant mouse TNF-alpha (0.5 microg/mouse). Cytochrome c release and processing of procaspases in the liver were analyzed by Western blotting. Activities of caspases were measured using chromogenic peptides as substrates. Ceramide content was determined using Escherichia coli diacylglycerol kinase. RESULTS: Apoptosis of hepatocytes was observed in mice treated with both GalN and TNF-alpha (GalN/TNF-alpha), but not GalN or TNF-alpha alone. Activation of caspases-9 and -3, and cytochrome c release were observed only in liver from mice treated with GalN/TNF-alpha. In a cell-free system, processing of procaspases-9 and -3, and cytochrome c release were observed in the postnuclear fraction of liver obtained from GalN/TNF-alpha-treated mice, but not in that from control mice. Processing of procaspase-3 was inhibited by a caspase-9 inhibitor, but not by inhibitor for caspase-8 or -2. In a reconstitution assay system, procaspase-9 processing occurred, when both cytosol and membrane fractions were obtained from the liver of mice treated with GalN/TNF-alpha. Ceramide accumulation was observed only in apoptotic liver and preceded cytochrome c release and caspase activation. CONCLUSION: Cytochrome c release and caspase-9 activation are required for the activation of executor caspase-3 in TNF-alpha-induced hepatocyte apoptosis, but caspases-8 and -2 play, if any, a minimal role. Ceramide may be implicated in this apoptotic process.


Subject(s)
Apoptosis/physiology , Caspases/metabolism , Galactosamine/immunology , Hepatocytes/physiology , Tumor Necrosis Factor-alpha/physiology , Animals , Blotting, Western , Ceramides/metabolism , Cytochrome c Group/metabolism , Enzyme Activation/drug effects , Hepatocytes/drug effects , Hepatocytes/metabolism , Immunization , In Situ Nick-End Labeling , Male , Mice , Mice, Inbred BALB C , Signal Transduction
3.
Bioorg Med Chem Lett ; 11(16): 2157-9, 2001 Aug 20.
Article in English | MEDLINE | ID: mdl-11514159

ABSTRACT

We examined the reactivity of 3-alkyl group homologues of farnesyl diphosphate or isopentenyl diphosphate for medium-chain prenyl diphosphate synthases, hexaprenyl diphosphate- or heptaprenyl diphosphate synthase. But-3-enyl diphosphate, which lacks the methyl group at the 3-position of isopentenyl diphosphate, condensed only once with farnesyl diphosphate to give E-norgeranylgeranyl diphosphate by the action of either enzyme. However, norfarnesyl diphosphate was never accepted as an allylic substrate at all. 3-Ethylbut-3-enyl diphosphate also reacted with farnesyl diphosphate giving a mixture of (all-E)-3-ethyl-7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl- and (all-E)-3,7-diethyl-11,15,19-trimethylicosa-2,6,10,14,18-pentaenyl diphosphates by hexaprenyl diphosphate synthase. On the other hand, heptaprenyl diphosphate synthase reaction of 3-ethylbut-3-enyl diphosphate with farnesyl diphosphate gave only (all-E)-3-ethyl-7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl diphosphate.


Subject(s)
Alkyl and Aryl Transferases/metabolism , Diphosphates/metabolism , Diphosphates/chemical synthesis , Diphosphates/chemistry , Substrate Specificity
4.
Biochem Biophys Res Commun ; 286(4): 673-7, 2001 Aug 31.
Article in English | MEDLINE | ID: mdl-11520048

ABSTRACT

In hepatoma Huh-7 cells, inhibition of sphingosine kinase (SphK) activity by N,N-dimethylsphingosine (DMS) resulted in up-regulated production of liver-specific serum proteins including albumin and alpha-fetoprotein (AFP). The changes in these protein levels coincided well with those of two liver-enriched transcription factors, hepatocyte nuclear factor (HNF)-1 and -4, which regulate a number of liver-specific genes at the transcriptional level. Moreover, DMS induced the expression of retinoic acid receptor-alpha and retinoid X receptor-alpha. In DMS-treated cells, 9-cis retinoic acid (RA) further enhanced HNF-4alpha and albumin expression but it inhibited AFP accumulation. These results suggest that activation of SphK disengages cells from their liver-specific phenotype, and that 9-cis RA further induces differentiation of hepatoma cells when SphK activity is inhibited.


Subject(s)
DNA-Binding Proteins , Hepatocytes/metabolism , Lysophospholipids , Nuclear Proteins , Phosphoproteins/physiology , Phosphotransferases (Alcohol Group Acceptor)/physiology , Receptors, Retinoic Acid/physiology , Transcription Factors/physiology , Alitretinoin , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors , Carcinoma, Hepatocellular , Cell Differentiation , Enzyme Inhibitors/pharmacology , Hepatocyte Nuclear Factor 1 , Hepatocyte Nuclear Factor 1-alpha , Hepatocyte Nuclear Factor 1-beta , Hepatocyte Nuclear Factor 4 , Humans , Liver/metabolism , Mitogen-Activated Protein Kinase 3 , Mitogen-Activated Protein Kinases/metabolism , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Retinoic Acid Receptor alpha , Retinoid X Receptors , Serum Albumin/metabolism , Sphingosine/analogs & derivatives , Sphingosine/pharmacology , Tretinoin/pharmacology , Tumor Cells, Cultured , alpha-Fetoproteins/metabolism
5.
J Immunol ; 167(1): 173-80, 2001 Jul 01.
Article in English | MEDLINE | ID: mdl-11418646

ABSTRACT

Human hepatocytes usually are resistant to TNF-alpha cytotoxicity. In mouse or rat hepatocytes, repression of NF-kappaB activation is sufficient to induce TNF-alpha-mediated apoptosis. However, in both Huh-7 human hepatoma cells and Hc human normal hepatocytes, when infected with an adenovirus expressing a mutated form of IkappaBalpha (Ad5IkappaB), which almost completely blocks NF-kappaB activation, >80% of the cells survived 24 h after TNF-alpha stimulation. Here, we report that TNF-alpha activates other antiapoptotic factors, such as sphingosine kinase (SphK), phosphatidylinositol 3-kinase (PI3K), and Akt kinase. Pretreatment of cells with N,N-dimethylsphingosine (DMS), an inhibitor of SphK, or LY 294002, an inhibitor of PI3K that acts upstream of Akt, increased the number of apoptotic cells induced by TNF-alpha in Ad5IkappaB-infected Huh-7 and Hc cells. TNF-alpha-induced activations of PI3K and Akt were inhibited by DMS. In contrast, exogenous sphingosine 1-phosphate, a product of SphK, was found to activate Akt and partially rescued the cells from TNF-alpha-induced apoptosis. Although Akt has been reported to activate NF-kappaB, DMS and LY 294002 failed to prevent TNF-alpha-induced NF-kappaB activation, suggesting that the antiapoptotic effects of SphK and Akt are independent of NF-kappaB. Furthermore, apoptosis mediated by Fas ligand (FasL) involving Akt activation also was potentiated by DMS pretreatment in Hc cells. Sphingosine 1-phosphate administration partially protected cells from FasL-mediated apoptosis. These results indicate that not only NF-kappaB but also SphK and PI3K/Akt are involved in the signaling pathway(s) for protection of human hepatocytes from the apoptotic action of TNF-alpha and probably FasL.


Subject(s)
Apoptosis/immunology , Hepatocytes/enzymology , Lysophospholipids , Phosphatidylinositol 3-Kinases/physiology , Protein Serine-Threonine Kinases/physiology , Proto-Oncogene Proteins/physiology , Sphingosine/analogs & derivatives , Sphingosine/biosynthesis , Sphingosine/immunology , Tumor Necrosis Factor-alpha/pharmacology , Adenoviridae/genetics , Adjuvants, Immunologic/antagonists & inhibitors , Adjuvants, Immunologic/pharmacology , Apoptosis/genetics , Caspases/metabolism , Cell Line , DNA Fragmentation/immunology , Enzyme Activation/genetics , Enzyme Activation/immunology , Fas Ligand Protein , Hepatocytes/cytology , Hepatocytes/immunology , Hepatocytes/virology , Humans , I-kappa B Proteins/genetics , Ligands , Membrane Glycoproteins/antagonists & inhibitors , Membrane Glycoproteins/pharmacology , NF-kappa B/antagonists & inhibitors , NF-kappa B/metabolism , Phosphoinositide-3 Kinase Inhibitors , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Protein Serine-Threonine Kinases/antagonists & inhibitors , Proto-Oncogene Proteins/antagonists & inhibitors , Proto-Oncogene Proteins c-akt , Signal Transduction/genetics , Signal Transduction/immunology , Sphingosine/metabolism , Sphingosine/pharmacology , Tumor Cells, Cultured , fas Receptor/metabolism
6.
Dig Dis Sci ; 46(5): 1046-56, 2001 May.
Article in English | MEDLINE | ID: mdl-11341648

ABSTRACT

For the development of a bioartificial liver (BAL) support device, it is most important to establish highly differentiated liver cells cultured at high density. When rat hepatocytes were cultured on a basement membrane matrix, Engelbreth-Holm-Swarm (EHS) gel, their rates of albumin secretion were very high, as measured by ELISA, and these high rates were maintained for more than three weeks of culturing. This level of activity greatly exceeded that of hepatocytes cultured on a plastic substratum, poly-N-p-vinylbenzyl-D-lactonamide (PVLA), on a single layer of collagen, or in a collagen sandwich culture. In an in vitro perfusion experiment, rat hepatocytes rapidly and completely removed ammonia from Eagle's MEM supplemented with 0.2 mM NH4Cl, although ammonia levels of the medium serially increased in modules containing HepG2 cells. A hybrid liver support system was developed and consisted of plasma perfusion through porous hollow fiber modules inoculated with 10 billion porcine hepatocytes entrapped in EHS gel. This system was applied to pigs with ischemic liver failure 8 hr after creation of a portocaval shunt and hepatic devascularization. In animals treated with the BAL support system, blood bicarbonate levels were increased immediately after treatment, and hemodynamic stability was improved. In control pigs, on the other hand, blood bicarbonate levels and blood pressure remained low. Plasma levels of ammonia and lactate decreased in pigs treated with the BAL device, but not in control animals. These results indicate that primary hepatocytes outperform HepG2 cells as a source of biotransformation functions in a BAL system and that the use of a BAL support device in combination with a hollow fiber module and hepatocytes entrapped in EHS gel has potential advantages for clinical use in patients with fulminant hepatic failure.


Subject(s)
Basement Membrane , Hepatocytes/physiology , Lactose/analogs & derivatives , Liver, Artificial , Ammonia/metabolism , Animals , Cells, Cultured , Collagen , Culture Media , Gels , Lactates/metabolism , Liver Failure, Acute/therapy , Male , Polystyrenes , Rats , Rats, Wistar , Swine
7.
J Cell Physiol ; 187(3): 374-85, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11319761

ABSTRACT

Intravenous administration of tumor necrosis factor-alpha (TNF-alpha) (0.5 microg/mouse) caused hepatocyte apoptosis in BALB/c mice when they were sensitized with D-galactosamine (GalN, 20 mg/mouse). Activation of nuclear factor kappa B (NF-kappa B) and expression of apoptotic Bcl-2 family members were not significantly different between livers of mice treated with TNF-alpha alone and GalN + TNF-alpha, indicating that neither activation of NF-kappa B nor expression of Bcl-2 family is involved in the sensitization by GalN against TNF-alpha-induced hepatocyte apoptosis. To identify differentially expressed genes implicated in GalN-induced hepatocyte sensitization, we adopted mRNA fingerprinting using an arbitrarily primed polymerase chain reaction. The present analysis revealed that mRNA expression of extracellular antioxidant, selenoprotein P, was up-regulated in the livers after GalN administration. GalN-induced increase in its protein level was confirmed by Western blotting. Increased expression of this gene was also observed in the liver of mice treated with concanavalin A, but not anti-Fas antibody. mRNA of another antioxidant, glutathione peroxidase-1, was also up-regulated, and lipid peroxides were produced in the liver after GalN administration. Selenoprotein P mRNA level also increased in Huh-7 human hepatoma cells incubated with GalN (5 or 10 mM). Accordingly, formation of reactive oxygen species (ROS) was observed in GalN-treated Huh-7 cells. H(2)O(2) induced up-regulation of selenoprotein P mRNA and sensitized Huh-7 cells to TNF-alpha-induced apoptosis. These results suggest that ROS produced by GalN may play a pivotal role in hepatocyte sensitization toward TNF-alpha-induced apoptosis.


Subject(s)
Apoptosis/drug effects , Galactosamine/pharmacology , Hepatocytes/metabolism , Proteins , Reactive Oxygen Species/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Animals , Antibodies/pharmacology , Carcinoma, Hepatocellular/metabolism , Cell Line , Concanavalin A/pharmacology , Drug Synergism , Gene Expression Profiling , Glutathione Peroxidase/metabolism , Hepatocytes/cytology , Hepatocytes/drug effects , Humans , Hydrogen Peroxide/pharmacology , JNK Mitogen-Activated Protein Kinases , Liver/drug effects , Liver/metabolism , Liver/pathology , Liver Neoplasms/metabolism , Male , Mice , Mice, Inbred BALB C , Mitogen-Activated Protein Kinases/metabolism , NF-kappa B/metabolism , Protein Biosynthesis , Proto-Oncogene Proteins c-bcl-2/biosynthesis , Proto-Oncogene Proteins c-bcl-2/genetics , RNA, Messenger/biosynthesis , Selenoprotein P , Selenoproteins , Specific Pathogen-Free Organisms , fas Receptor/immunology , Glutathione Peroxidase GPX1
8.
J Gastroenterol ; 36(11): 787-9, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11757753

ABSTRACT

We encountered a case of left hepatic duct cancer that developed 7 years after surgical resection of early-stage adenocarcinoma of the gallbladder. A 65-year-old woman was hospitalized with high fever and general fatigue. She also had elevated serum levels of alkaline phosphatase, gamma-glutamyltranspeptidase, and carbohydrate antigen 19-9. Seven years earlier, she had undergone extended cholecystectomy and resection of the extrahepatic bile duct for early-stage mucinous adenocarcinoma of the gallbladder. Conventional examinations did not reveal any responsible lesions. Magnetic resonance (MR) cholangiography, however, showed a tumor obstructing the left hepatic duct, and dynamic MR images revealed multiple foci of bacterial abscess in the liver. Surgically resected tissue again revealed mucinous adenocarcinoma. The present case is rare in that metachronous mucinous adenocarcinoma of the biliary system occurred after a long interval. This case suggests the usefulness of MR imaging in the postsurgical monitoring of patients with gallbladder carcinoma.


Subject(s)
Adenocarcinoma, Mucinous/pathology , Adenocarcinoma, Mucinous/surgery , Bile Duct Neoplasms/pathology , Bile Duct Neoplasms/surgery , Gallbladder Neoplasms/pathology , Gallbladder Neoplasms/surgery , Magnetic Resonance Imaging , Neoplasms, Second Primary/pathology , Neoplasms, Second Primary/surgery , Aged , Cholangiography , Female , Humans , Postoperative Care
9.
Hepatology ; 32(6): 1272-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11093734

ABSTRACT

Tumor necrosis factor alpha (TNF-alpha) binding to the TNF receptor (TNFR) initiates apoptosis and simultaneously activates the transcription factor, nuclear factor-kappaB (NF-kappaB), which suppresses apoptosis by an unknown mechanism. Pretreatment with TNF-alpha or interleukin-1beta (IL-1beta), which activated NF-kappaB in the liver, dramatically prevented TNF-alpha-induced liver-cell apoptosis in D-galactosamine (GalN)-sensitized mice, but not anti-Fas antibody-induced hepatotoxicity. This protective effect of TNF-alpha continued for 5 hours after TNF-alpha administration, a time course similar to that found in NF-kappaB activation after TNF-alpha administration. In mice treated with adenoviruses expressing a mutant form of IkappaB, the antiapoptotic effect of TNF-alpha was inhibited in part. Prior TNF-alpha administration was not found to block the activation of caspase-8, although caspase-3 was inhibited in mice treated with TNF-alpha plus GalN/TNF-alpha compared with mice treated with GalN/TNF-alpha. These results indicate that TNFR and Fas independently regulate murine apoptotic liver failure, and that a rapid defense mechanism induced by the activation of NF-kappaB blocks death-signaling at the initiation stage of hepatic apoptosis mediated by TNFR, probably downstream of caspase-8, but not by Fas.


Subject(s)
Apoptosis/drug effects , Hepatocytes/physiology , NF-kappa B/physiology , Receptors, Tumor Necrosis Factor/physiology , Tumor Necrosis Factor-alpha/pharmacology , fas Receptor/physiology , Animals , Antibodies/pharmacology , Caspase 8 , Caspase 9 , Caspases/metabolism , DNA/metabolism , Drug Combinations , Galactosamine/pharmacology , I-kappa B Proteins/antagonists & inhibitors , Interleukin-1/pharmacology , Liver/drug effects , Liver/metabolism , Male , Mice , Mice, Inbred BALB C , NF-kappa B/metabolism , fas Receptor/immunology
10.
J Infect Dis ; 182(4): 1103-8, 2000 Oct.
Article in English | MEDLINE | ID: mdl-10979906

ABSTRACT

Serum pro- and anti-inflammatory mediators in patients with acute liver diseases were assessed to clarify the clinical significance of these measurements in relation to disease severity. Concentrations of circulating tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-10, IL-12, and soluble TNF receptors (sTNFR) p55 and p75 were measured at admission in patients with fulminant hepatitis (FH; n=19), severe acute hepatitis (AHS, n=15), or acute hepatitis (AH, n=7). Serum concentrations of TNF-alpha, IL-10, and sTNFR-55 were significantly higher in patients with FH than in those with AHS (P<.05, <.05, and <.01, respectively) or AH (P<.05). Serum IL-10 and TNF-alpha levels were higher in patients who died of FH (n=13) than in FH survivors (n=6; P<.05). The ratios between TNF-alpha and IL-10 and sTNFR-55 or sTNFR-75 were not valuable in predicting mortality and disease severity. However, both proinflammatory cytokine TNF-alpha and anti-inflammatory cytokine IL-10 levels at admission were associated with fatal outcome among patients with FH.


Subject(s)
Biomarkers/blood , Hepatic Encephalopathy/blood , Hepatic Encephalopathy/mortality , Interleukin-10/blood , Tumor Necrosis Factor-alpha/analysis , Adult , Aged , Antigens, CD/blood , Hepatic Encephalopathy/immunology , Hepatitis/blood , Hepatitis/immunology , Hepatitis, Viral, Human/blood , Hepatitis, Viral, Human/immunology , Humans , Interleukin-6/blood , Middle Aged , Predictive Value of Tests , Receptors, Tumor Necrosis Factor/blood , Receptors, Tumor Necrosis Factor, Type I , Receptors, Tumor Necrosis Factor, Type II , Survival Analysis , Tumor Necrosis Factor-alpha/metabolism
11.
J Hepatol ; 32(3): 488-96, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10735620

ABSTRACT

BACKGROUND/AIMS: The extracellular matrix plays an essential role in the regulation of cell proliferation in different cell types. However, the regulation of cell cycle control in hepatocytes in response to growth factors and extracellular matrix signals is not well understood. The aims of this study were to investigate the expression of key cell cycle control elements, including cyclins, A and D1, and cyclin-dependent kinase inhibitors, p21 and p27, in rat hepatocytes in primary culture on dried collagen or Engelbreth-Holm-Swarm in the presence of epidermal growth factor. METHODS: Hepatocytes prepared from Wistar rats were cultured on various extracellular matrix in Williams medium E in the presence or absence of 20 ng/ ml epidermal growth factor. DNA synthesis was measured by [3H]thymidine uptake and mRNA expression of cell cycle-related genes was determined by reverse transcription polymerase chain reaction. RESULTS: Cyclins D1 and A mRNA levels were high at the G1/S boundary in epidermal growth factor-stimulated hepatocytes cultured on dried collagen. In contrast to spread cells, hepatocytes cultured on an Engelbreth-Holm-Swarm gel that were prevented from spreading failed to progress through the G1 phase and enter the S phase. This shape-dependent blockage of cell cycle progression correlated with the up-regulation of the cell cycle inhibitors p21 and p27. CONCLUSIONS: Changes in hepatocyte-extracellular matrix interactions may control hepatocyte growth within the local microenvironment by modulating cell shape and regulating cyclins and the cyclin-dependent kinase inhibitors p21 and p27.


Subject(s)
Cell Cycle Proteins , Cell Cycle/physiology , Cyclins/metabolism , Extracellular Matrix/physiology , Liver/cytology , Liver/metabolism , Microtubule-Associated Proteins/metabolism , Tumor Suppressor Proteins , Animals , Cells, Cultured , Cyclin-Dependent Kinase Inhibitor p21 , Cyclin-Dependent Kinase Inhibitor p27 , Cyclins/genetics , DNA/biosynthesis , Epidermal Growth Factor/pharmacology , Male , Microtubule-Associated Proteins/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar
12.
J Hepatol ; 31(6): 997-1005, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10604572

ABSTRACT

BACKGROUND/AIMS: Tumor necrosis factor a (TNF-alpha) and Fas ligand are apoptotic cell-death mediators that act by binding to their responsive receptors. The aims of this study were to assess the differences between liver cell deaths induced by TNF-alpha and anti-Fas antibody, and to investigate the mechanism by which GalN sensitizes the hepatocyte to injury by TNF-alpha. METHODS: TNF-alpha or anti-Fas antibody was injected into BALB/c mice sensitized or unsensitized by D-galactosamine (GalN). Liver injury was assessed biochemically and histologically. The expressions of TNF receptor (TNFR)1 and TNFR2 mRNA in the liver were determined by Northern blot analysis. Nuclear factor-kappaB (NF-kappaB) DNA binding activity was determined by gel shift assay. RESULTS: In GalN-sensitized mice, hepatocyte apoptosis and liver failure were observed after TNF-alpha injection, but neither occurred in unsensitized mice. Microscopically, GalN preceding TNF-alpha caused massive hemorrhagic liver damage with fragmented hepatocyte nuclei resembling effects of anti-Fas antibody, but GalN largely failed to sensitize to injury by this antibody. TNFR1 mRNA expression in the liver was upregulated within 3 h after GalN administration, and anti-TNFR1 antibody protected GalN-sensitized mice from hepatotoxic effects of TNF-alpha. GalN treatment failed to affect TNF-alpha-induced NF-kappaB activation. CONCLUSIONS: Unlike Fas-related apoptosis, TNFR-mediated apoptosis requires hepatocyte sensitization involving TNFR1 upregulation.


Subject(s)
Apoptosis , Liver/pathology , Receptors, Tumor Necrosis Factor/metabolism , Animals , Antibodies/immunology , Fas Ligand Protein , Liver/immunology , Liver/metabolism , Male , Membrane Glycoproteins/metabolism , Mice , Mice, Inbred BALB C , NF-kappa B/metabolism , fas Receptor/immunology , fas Receptor/metabolism
13.
J Hepatol ; 31(5): 815-24, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10580578

ABSTRACT

BACKGROUND/AIMS: Proinflammatory cytokines including tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) play a critical role in the pathogenesis of liver injury induced by lipopolysaccharide (LPS) or staphylococcal enterotoxin B (SEB) in D-galactosamine (GalN)-sensitized mice. The aim of this study was to examine the ability of interleukin-10 (IL-10), a recently characterized, highly potent anti-inflammatory mediator, to protect sensitized mice against hepatotoxicity induced by SEB or LPS. METHODS: IL-10 was injected at various concentrations into BALB/c mice treated by GalN/SEB or GalN/LPS. Liver injury was assessed biochemically and histologically. Serum levels of TNF-alpha and IFN-gamma were measured and the expressions of TNF-alpha and IFN-gamma mRNA in the liver and spleen were determined by reverse-transcription polymerase chain reaction. RESULTS: Treatment with IL-10 markedly reduced serum transaminase activities in a dose-dependent manner and reduced hemorrhagic liver damage in sensitized mice exposed to either toxin. IL-10 also inhibited increases in serum TNF-alpha and IFN-gamma concentrations with either toxin. Treatment with IL-10 significantly reduced TNF-alpha mRNA and IFN-gamma mRNA expression in the liver and spleen after administration of either toxin to sensitized mice. CONCLUSIONS: These findings suggest that IL-10 is capable of regulating both T cell- and macrophage-mediated hepatic injury in vivo and that this cytokine might be useful in the treatment of acute liver failure.


Subject(s)
Enterotoxins/toxicity , Galactosamine/toxicity , Gene Expression Regulation/immunology , Interferon-gamma/genetics , Interleukin-10/pharmacology , Lipopolysaccharides/toxicity , Liver/drug effects , Transcription, Genetic/immunology , Tumor Necrosis Factor-alpha/genetics , Animals , Cells, Cultured , Gene Expression Regulation/drug effects , Interferon-gamma/blood , Liver/immunology , Liver/pathology , Male , Mice , Mice, Inbred BALB C , RNA, Messenger/genetics , Spleen/drug effects , Spleen/immunology , Spleen/pathology , Superantigens/toxicity , Transcription, Genetic/drug effects
14.
Am J Gastroenterol ; 94(9): 2531-3, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10484019

ABSTRACT

An 80-yr-old woman with advanced hilar cholangiocarcinoma underwent a placement of endoscopic biliary drainage (EBD) tube from the common hepatic to common bile duct through the stricture. Magnetic resonance cholangiography clearly demonstrated the later dislocation and obstruction of the EBD tube. The present case suggests that magnetic resonance cholangiography may be a potentially useful tool in the management of EBD tubes.


Subject(s)
Cholangiography , Cholestasis/diagnosis , Cholestasis/surgery , Drainage/instrumentation , Magnetic Resonance Imaging , Aged , Aged, 80 and over , Bile Duct Neoplasms/complications , Cholestasis/etiology , Endoscopy, Digestive System , Female , Humans
16.
Dig Dis Sci ; 44(4): 796-805, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10219841

ABSTRACT

Adhesions of leukocytes to hepatocytes and sinusoidal endothelial cells mediates the induction and progression of hepatic injury. However, in contrast to endothelial cells, information regarding the regulation of interactions between leukocytes and hepatocytes is limited. In the present study, we investigated the effect of inflammatory mediators including lipopolysaccharide (LPS), staphylococcal enterotoxin B (SEB), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) on the adhesion of polymorphonuclear leukocytes or lymphocytes to primary cultured rat hepatocytes, and on the expression of intercellular adhesion molecule-1 (ICAM-1) gene in hepatocytes. Both polymorphonuclear leukocyte and lymphocyte adhesion to hepatocytes were enhanced after exposure of hepatocytes to IFN-gamma and TNF-alpha, but not after exposure to LPS, SEB or IL-1beta. The adhesion induced by either IFN-gamma or TNF-alpha was inhibited by monoclonal antibodies against ICAM-1 or lymphocyte function-associated antigen-1 (LFA-1). Nonstimulated hepatocytes expressed faintly ICAM-1 mRNA, which increased slightly during the culture period. ICAM-1 mRNA expression was up-regulated to a greater extent by incubating hepatocytes with IFN-gamma or TNF-alpha, and peaked after 12 hr of incubation with TNF-alpha and after 24 hr with IFN-gamma. These results indicate that IFN-gamma and TNF-alpha induce the expression of ICAM-1 on parenchymal hepatocytes and that the LFA-1-ICAM-1 pathway plays an important role in the interaction between hepatocytes and neutrophils or lymphocytes.


Subject(s)
Cytokines/metabolism , Intercellular Adhesion Molecule-1/metabolism , Leukocytes/metabolism , Liver/immunology , Liver/metabolism , Animals , Antibodies, Monoclonal/immunology , Blotting, Northern , Cell Adhesion/immunology , Cells, Cultured , Enterotoxins/metabolism , Gene Expression Regulation , Intercellular Adhesion Molecule-1/genetics , Intercellular Adhesion Molecule-1/immunology , Interferon-gamma/metabolism , Interleukin-1/metabolism , Lipopolysaccharides/metabolism , Liver/cytology , Lymphocyte Function-Associated Antigen-1/immunology , Lymphocyte Function-Associated Antigen-1/metabolism , Male , RNA, Messenger/biosynthesis , Rats , Rats, Wistar , Tumor Necrosis Factor-alpha/metabolism
17.
Eur J Morphol ; 36 Suppl: 123-7, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9825906

ABSTRACT

In addition to seromucous cells and a few mucous cells (Type II cells), submandibular glands of 2-8 month old rats contain two additional cell types: type III and type IV. Type III cells contain serous-type secretory granules that sometimes have a complex substructure; type IV cells appear to be seromucous, but their granules clearly are different from those in conventional endpiece seromucous cells. Both type III and IV cells are involved in histogenesis of new endpieces in a process that differs markedly from that occurring in perinatal glands. In this process, intercalated ducts bud and give rise to immature endpieces that consist entirely of type III cells. These differentiate into type IV cells, which in turn differentiate into standard seromucous cells. Concurrently, the intercalated ducts become shorter as their most distal cells differentiate into granular duct cells. This type of developmental process begins approximately 2 months postnatally, when histogenesis of endpieces by means of terminal tubules has ended, and continues until 6 months, when its frequency sharply declines.


Subject(s)
Submandibular Gland , Animals , Cytoplasmic Granules/metabolism , Cytoplasmic Granules/ultrastructure , Epithelial Cells/metabolism , Epithelial Cells/ultrastructure , Female , Male , Microscopy, Electron , Rats , Rats, Sprague-Dawley , Submandibular Gland/cytology , Submandibular Gland/growth & development , Submandibular Gland/metabolism
18.
Crit Care Med ; 26(5): 873-6, 1998 May.
Article in English | MEDLINE | ID: mdl-9590317

ABSTRACT

OBJECTIVES: To compare the circulating concentrations of endotoxin and cytokines in patients with fulminant hepatitis and patients with the severe form of acute hepatitis, and to assess the effects of plasma exchange on the circulating concentrations of these inflammatory mediators in patients with acute hepatic failure. DESIGN: Prospective, consecutive entry study of patients meeting fulminant hepatitis criteria and the severe form of acute hepatitis criteria. SETTING: University hospital, intensive care unit. PATIENTS: Five patients with fulminant hepatitis, eight patients with the severe form of acute hepatitis, two patients with acute-on-chronic hepatic failure, and one patient with postoperative hepatic failure. INTERVENTIONS: Plasma endotoxin, serum tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 were determined on admission in five patients with fulminant hepatitis and eight patients with the severe form of acute hepatitis. Circulating concentrations of the inflammatory mediators were measured before and after a single course of plasma exchange in eight patients with acute liver failure, including five patients with fulminant hepatitis, two patients with acute-on-chronic hepatic failure, and one patient with postoperative hepatic failure. MEASUREMENTS AND MAIN RESULTS: TNF-alpha and IL-6 in patients with fulminant hepatitis were significantly higher than in patients with the severe form of acute hepatitis, whereas endotoxin concentrations did not differ between patients with fulminant hepatitis or the severe form of acute hepatitis. IL-1beta was not detectable in patients with either fulminant hepatitis or the severe form of acute hepatitis. Plasma endotoxin concentrations decreased immediately after plasma exchange. Serum concentrations of TNF-alpha and IL-6 were significantly lower after plasma exchange than before plasma exchange. CONCLUSION: TNF-alpha and IL-6 may be important in the pathogenesis of the clinical symptoms that differentiate fulminant hepatitis from the severe form of acute hepatitis, and plasma exchange removes these inflammatory mediators from the circulation of patients with severe liver disease.


Subject(s)
Endotoxins/blood , Hepatic Encephalopathy/therapy , Interleukins/blood , Liver Failure, Acute/therapy , Plasma Exchange , Tumor Necrosis Factor-alpha/metabolism , Adolescent , Adult , Aged , Hepatic Encephalopathy/blood , Humans , Intensive Care Units , Liver Failure, Acute/blood , Middle Aged , Prospective Studies
19.
Bioorg Med Chem Lett ; 8(18): 2549-54, 1998 Sep 22.
Article in English | MEDLINE | ID: mdl-9873578

ABSTRACT

3-Alkyl group homologs of isopentenyl diphosphate were examined for the reactivity as substrates of the thermostable farnesyl diphosphate (FPP) synthase of Bacillus stearothermophilus. Even 3-n-propyl- and 3-n-butyl-but-3-enyl diphosphates, which are hardly acceptable by animal FPP synthases, are accepted by this bacterial enzyme as substrates to react with dimethylallyl- and geranyl diphosphates, yielding 7-methyl-3-n-propylocta-2,6-dienyl- and 7,11-dimethyl-3-n-propyldodeca-2,6,10-trienyl diphosphate, respectively.


Subject(s)
Alkyl and Aryl Transferases/metabolism , Antigens, Bacterial/chemistry , Hemiterpenes , Organophosphorus Compounds/chemistry , Alkylation , Animals , Antigens, Bacterial/metabolism , Chromatography, High Pressure Liquid , Geobacillus stearothermophilus , Geranyltranstransferase , Liver/enzymology , Organophosphorus Compounds/metabolism , Substrate Specificity , Swine
20.
Biochem Biophys Res Commun ; 238(2): 539-43, 1997 Sep 18.
Article in English | MEDLINE | ID: mdl-9299547

ABSTRACT

Transforming growth factor beta (TGF-beta) is a potent inhibitor of the proliferation of many cell types. We investigated the effects of TGF-beta1 on cyclin D1, cyclin A, p21, p27, and p53 mRNA expressions in primary cultured rat hepatocytes by the reverse-transcription polymerase chain reaction (RT-PCR) method. TGF-beta1 decreased the level of cyclin A mRNA in a dose-dependent manner, while it had little effect on the level of cyclin D1 mRNA. p21 mRNA expression was greatly induced by TGF-beta1 in a p53-independent mechanism, while p27 mRNA expression was not affected by TGF-beta1. These results suggest that TGF-beta1 may inhibit liver cell proliferation by regulating p21 and cyclin A mRNAs.


Subject(s)
Cell Cycle Proteins/genetics , Cell Cycle/genetics , Gene Expression Regulation/drug effects , Liver/cytology , Transforming Growth Factor beta/pharmacology , Animals , Cell Cycle Proteins/biosynthesis , Cells, Cultured , Liver/metabolism , Male , Rats , Rats, Wistar
SELECTION OF CITATIONS
SEARCH DETAIL
...