bluuebunny/crossref_metadata_2025 huggingface dataset:
The p21Cip1 protein, a cyclin inhibitor, regulates the levels and the intracellular localization of CDC25A in mice regenerating livers
Authors: Jaime Maribel , Pujol Maria Jessús , Serratosa Joan , Pantoja Cristina , Canela Núria , Casanovas Oriol , Serrano Manuel , Agell Neus , Bachs Oriol
Published: February 2003

Liver cells from p21Cip1−/− mice subjected to partial hepatectomy (PH) progress into DNA synthesis faster than those from wild-type mice. These cells also show a premature induction of cyclin E/cyclin-dependent kinase (CDK) 2 activity. We studied the mechanisms whereby cells lacking p21Cip1 showed a premature induction of this activity. Whereas the levels of CDK2, cyclin E, and p27Kip1 were similar in both wild-type and p21Cip1−/− mice, those of the activator CDC25A were much higher in p21Cip1−/− quiescent and regenerating livers than in wild-type animals. Moreover, p21Cip1−/− cells also showed a premature translocation of CDC25A from cytoplasm into the nucleus. The ectopic expression of p21Cip1 into mice embryo fibroblasts from p21Cip1−/− mice decreased the levels of CDC25A and delayed its nuclear translocation. The levels of CDC25A messenger RNA in p21Cip1−/− cells were higher than in wild-type cells, suggesting that this increase might be responsible, at least in part, for the high levels of CDC25A protein in these cells. Thus, the results reported here indicate that p21Cip1 regulates the levels and the intracellular localization of CDC25A. We also found a good correlation between CDC25A nuclear translocation and cyclin E/CDK2 activation. In conclusion, premature translocation of CDC25A to the nucleus might be involved in the advanced induction of cyclin E/CDK2 activity and DNA replication in cells from animals lacking p21Cip1.
Bilirubin induces apoptosis via the mitochondrial pathway in developing rat brain neurons
Authors: Rodrigues Cecília M. P. , Solá Susana , Brites Dora
Published: February 2003

Increased levels of unconjugated bilirubin, the end-product of heme catabolism, are detrimental to the central nervous system. To examine the role of apoptosis in bilirubin-induced toxicity and to characterize the biochemical pathway of cell death, we exposed developing rat brain neurons to purified unconjugated bilirubin at concentrations below and above saturation of human serum albumin. Isolated neurons treated with bilirubin showed increased levels of apoptosis. Mitochondrial cytochrome c was extensively released and accumulated in cytosol. Consistent with this observation, caspase-3 was activated and the full-length substrate poly(ADP)ribose polymerase (PARP) degraded, even in the presence of very modestly elevated concentrations of bilirubin. In parallel, all events were prevented in cells preincubated with ursodeoxycholate. Further experiments showed that bilirubin diminished mitochondrial transmembrane potential (ΔΨm) and increased mitochondrial-associated Bax protein levels, while directly disrupting membrane lipid and protein structure. In conclusion, bilirubin induces mitochondrial depolarization and Bax translocation via physical interaction with membranes, mediating the mitochondrial pathway of apoptosis in neurons exposed to bilirubin. These results provide a novel insight into the mechanism of bilirubin-induced toxicity.
Hepatic ischemic preconditioning in mice is associated with activation of NF-κB, p38 kinase, and cell cycle entry
Authors: Teoh Narci , Pena Aileen Dela , Farrell Geoffrey
Published: February 2003

A brief period of hepatic ischemia protects the liver against subsequent ischemia-reperfusion (IR) injury, but the mechanism of such preconditioning is poorly understood. We examined whether preconditioning activated nuclear factor kappa B (NF-κB), the stress-activated protein kinases (SAPK), c-Jun N-terminal kinase-1 (JNK-1) and p38, and entry into the cell cycle. We used a murine model of partial hepatic ischemia. Preconditioning was performed by clamping the vasculature for 2 to 20 minutes, and allowing reperfusion for 10 minutes before 90-minute ischemia or IR. As assessed by serum alanine aminotransferase (ALT) levels and liver histology, preconditioning periods of 5 and 10 minutes were highly protective against IR injury, whereas 2-, 15-, and 20-minute intervals were ineffective. Preconditioning was associated with entry of hepatocytes into the cell cycle within 2 hours of subsequent IR, as indicated by proliferating cell nuclear antigen (PCNA) nuclear staining, induction of cyclin D1 and numerous mitotic figures; in the absence of preconditioning, such changes were not seen until 24 hours. Preconditioning increased nuclear binding of NF-κB within 30 minutes of the subsequent ischemic interval, paralleled by degradation of inhibitory (binding) protein for NF-κB (IκBα). Ischemic preconditioning also activated p38 kinase and JNK-1, which are known to converge on cyclin D1 regulation. The protective effect of the preconditioning regimen was more closely associated with p38 kinase than JNK-1 activation. In conclusion, the hepatoprotective effects of ischemic preconditioning are associated with activation of NF-κB and SAPKs that are associated with entry of hepatocytes into the cell cycle, a critical biological effect that favors survival of the liver against ischemic and IR injury.
Intrahepatic and circulating HLA class II-restricted, hepatitis C virus-specific T cells: Functional characterization in patients with chronic hepatitis C
Authors: Penna Amalia , Missale Gabriele , Lamonaca Vincenzo , Pilli Massimo , Mori Cristina , Zanelli Paola , Cavalli Albertina , Elia Gianfranco , Ferrari Carlo
Published: February 2003

To compare the functional features of circulating and intrahepatic hepatitis C virus (HCV)-specific CD4+ T cells in chronic HCV infection, peripheral blood and liver-infiltrating lymphocytes from 29 patients with chronic hepatitis C were stimulated with structural and nonstructural HCV proteins to produce antigen-specific T-cell lines and clones. Antigen specificity, fine specificity, phenotype, cytokine production, and T-cell receptor (TCR)-vβ chain expression were analyzed. The results indicate a hierarchy of stimulatory capacity by the different HCV proteins, core being the antigen most frequently recognized by CD4+ intrahepatic lymphocytes, followed by NS4 and NS5. The CD4 response was directed simultaneously against different HCV proteins in individual patients, but fine-specificity analysis indicated that the response was generally focused on a limited number of immunodominant epitopes. Although the narrowly focused nature of this response may favor the emergence of escape mutations, this event was not observed by following-up over time the sequence of 2 epitopes strongly immunodominant for intrahepatic CD4 cells of a patient with chronic HCV infection. In conclusion, simultaneous analysis of peripheral blood and intrahepatic CD4 cells in the same patients indicated a predominant Th1 profile of HCV-specific CD4 cells and suggests a specific compartmentalization of virus-specific T cells into the liver.
Randomized controlled trial of transarterial lipiodol chemoembolization for unresectable hepatocellular carcinoma
Authors: Lo Chung-Mau , Ngan Henry , Tso Wai-Kuen , Liu Chi-Leung , Lam Chi-Ming , Poon Ronnie Tung-Ping , Fan Sheung-Tat , Wong John
Published: February 2003

This randomized, controlled trial assessed the efficacy of transarterial Lipiodol (Lipiodol Ultrafluide, Laboratoire Guerbet, Aulnay-Sous-Bois, France) chemoembolization in patients with unresectable hepatocellular carcinoma. From March 1996 to October 1997, 80 out of 279 Asian patients with newly diagnosed unresectable hepatocellular carcinoma fulfilled the entry criteria and randomly were assigned to treatment with chemoembolization using a variable dose of an emulsion of cisplatin in Lipiodol and gelatin-sponge particles injected through the hepatic artery (chemoembolization group, 40 patients) or symptomatic treatment (control group, 40 patients). One patient assigned to the control group secondarily was excluded because of unrecognized systemic metastasis. Chemoembolization was repeated every 2 to 3 months unless there was evidence of contraindications or progressive disease. Survival was the main end point. The chemoembolization group received a total of 192 courses of chemoembolization with a median of 4.5 (range, 1-15) courses per patient. Chemoembolization resulted in a marked tumor response, and the actuarial survival was significantly better in the chemoembolization group (1 year, 57%; 2 years, 31%; 3 years, 26%) than in the control group (1 year, 32%; 2 years, 11%; 3 years, 3%; P = .002). When adjustments for baseline variables that were prognostic on univariate analysis were made with a multivariate Cox model, the survival benefit of chemoembolization remained significant (relative risk of death, 0.49; 95% CI, 0.29-0.81; P = .006). Although death from liver failure was more frequent in patients who received chemoembolization, the liver functions of the survivors were not significantly different. In conclusion, in Asian patients with unresectable hepatocellular carcinoma, transarterial Lipiodol chemoembolization significantly improves survival and is an effective form of treatment.
Role of CCR2 in macrophage migration into the liver during acetaminophen-induced hepatotoxicity in the mouse
Authors: Dambach Donna M. , Watson Linda M. , Gray Kevin R. , Durham Stephen K. , Laskin Debra L.
Published: February 2003

The biological effects of monocyte chemoattractant protein (MCP) 1 are mediated by binding to C-C chemokine receptor (CCR) 2. In the present studies, we used CCR2 knockout (CCR2−/−) mice to examine the role of MCP-1 in acetaminophen-induced macrophage accumulation in the liver, expression of inflammatory cytokines, and hepatotoxicity. We found that hepatic expression of CCR2 and MCP-1 was increased 10-fold and 20-fold, respectively, 12 to 72 hours after administration of acetaminophen to wild-type mice. Expression of these proteins was localized in centrilobular regions of the liver. Whereas MCP-1 was expressed by both hepatocytes and macrophages, CCR2 was identified in inflammatory macrophages. F4/80 is a marker of mature macrophages expressed in large quantities by Kupffer cells. In wild-type mice, a 75% decrease in F4/80-positive macrophages was observed 24 to 48 hours after administration of acetaminophen. In contrast, expression of macrosialin (CD68), a marker of activated macrophages, increased 2-fold 24 to 72 hours after administration of acetaminophen and was associated with inflammatory cells. Although there was a decrease in the overall severity of inflammation and in the number of macrosialin-positive macrophages 72 hours after administration of acetaminophen in CCR2−/− mice, the number of F4/80-positive cells did not change. Loss of CCR2 was also found to alter acetaminophen-induced expression of tumor necrosis factor α, monocyte chemoattractant protein 3, and KC/gro. However, the overall outcome of acetaminophen-induced hepatic injury was not affected. In conclusion, these data indicate that MCP-1 and CCR2 contribute to the recruitment of a subset of activated macrophages into the liver during acetaminophen-induced hepatotoxicity that may be important in resolution of tissue injury.
The pathobiology of biliary epithelia
Authors: Alpini Gianfranco , McGill James M. , LaRusso Nicholas F.
Published: February 2003

The morbidity and mortality from chronic biliary diseases (i.e., the cholangiopathies) remains substantial. End-stage liver disease from biliary causes of cirrhosis (e.g., primary biliary cirrhosis [PBC], and primary sclerosing cholangitis) account for approximately one third of patients referred for liver transplantation. A single-topic conference sponsored by the American Association for the Studies of Liver Diseases entitled “The Pathobiology of Biliary Epithelia” brought together investigators to review the status of the field of cholangiocyte pathobiology, identify new areas of interest, and propose future directions. This information was presented in 6 sessions: “Structural and Functional Characteristics of the Bile Duct System,” “Biological Topics from Nonbiliary Epithelia,” “Malignant Transformation of Cholangiocytes,” “Cholangiocyte Proliferation and Death,” “Transport Mechanisms in Bile Duct Epithelia,” and “Pathobiology of Biliary Epithelia.” In the 7 years since the first symposium on this topic, major advances have been made in our understanding of ductal bile formation, including, greater insight into the hormones, intracellular signaling mechanisms, and effector proteins responsible for bile secretion and absorption. More sophisticated imaging technologies have increased our understanding of the polarity of cholangiocytes, their embryology and ultrastructural anatomy, and in vivo human secretory responses to current medical therapy. Information on mediators of inflammation permeated many sessions, having potentially important roles in malignant transformation of cholangiocytes, cholangiocyte apoptosis, fluid and electrolyte transport, and have begun to be specifically characterized for certain biliary diseases, e.g., acquired immunodeficiency syndrome (AIDS) cholangiopathy and graft-versus-host disease (GVHD).
Leptin is required for fibrogenic responses induced by thioacetamide in the murine liver
Authors: Honda Hajime , Ikejima Kenichi , Hirose Miyoko , Yoshikawa Mutsuko , Lang Tie , Enomoto Nobuyuki , Kitamura Tsuneo , Takei Yoshiyuki , Sato Nobuhiro
Published: February 2003

In this study, we investigated hepatic fibrogenesis caused by long-term thioacetamide (TAA) administration in ob/ob mice, a naturally occurring leptin deficient animal. In the lean littermates, prominent hepatic fibrosis, as well as positive staining for α smooth muscle actin (α-SMA), was induced by treatment with TAA (200 μg/g, IP, 3 times per week) for 4 to 8 weeks as expected. In sharp contrast, almost no hepatic fibrosis developed in ob/ob mice given the equivalent doses of TAA, where specific staining for α-SMA barely was detected. Induction of α1(I) procollagen mRNA caused by TAA also was prevented in ob/ob mice almost completely. Further, transforming growth factor β (TGF-β) mRNA was increased in the liver after TAA treatment for 4 weeks in lean littermates, which also was prevented in ob/ob mice. Interestingly, fibrotic septa in the hepatic lobules, as well as increases in α1(I) procollagen mRNA, was observed in ob/ob mice, when they were injected with recombinant murine leptin (1 μg/g daily) in combination with TAA treatment. Leptin per se did not cause any fibrotic changes in the liver in ob/ob mice. These findings clearly indicated that leptin deficiency is responsible for the resistance to TAA-induced profibrogenic responses in ob/ob mice. In conclusion, leptin appears to promote profibrogenic responses in the liver, in part, by up-regulation of TGF-β.
Is obesity an independent risk factor for hepatocellular carcinoma in cirrhosis?
Authors: Nair Satheesh , Mason Andrew , Eason James , Loss George , Perrillo Robert P.
Published: February 2003

Recently, several epidemiologic observations have suggested that obesity might be an independent risk factor for certain malignancies such as breast cancer, colon cancer, renal cell carcinoma, and esophageal adenocarcinoma. However, there are no studies examining the risk of hepatocellular carcinoma (HCC) in obesity. The aim of the present study was to determine whether obesity is an independent risk factor for HCC in patients with cirrhosis. Explanted liver specimens from a national database on patients undergoing liver transplantation were examined for HCC, and the incidence was compared among patients with varying body mass indices according to the etiology of cirrhosis. A multivariate analysis was used for controlling other potentially confounding variables such as age and sex. Among 19,271 evaluable patients, the overall incidence of HCC was 3.4% (n = 659) with a slightly higher prevalence among obese patients compared with lean patients. Obesity was an independent predictor for HCC in patients with alcoholic cirrhosis (odds ratio [OR], 3.2; 95% CI, 1.5-6.6; P = .002) and cryptogenic cirrhosis (OR, 11.1; 95% CI, 1.5-87.4; P = .02). Obesity was not an independent predictor in patients with hepatitis C, hepatitis B, primary biliary cirrhosis, and autoimmune hepatitis. The higher risk of HCC in obese patients is confined to alcoholic liver disease and cryptogenic cirrhosis. In conclusion, more frequent surveillance for HCC may be warranted in obese patients with alcoholic and cryptogenic cirrhosis. However, as this study is based on patients with advanced cirrhosis, our findings need to be confirmed in a broader population of individuals with cirrhosis.
Peroxisomal localization of inducible nitric oxide synthase in hepatocytes
Authors: Stolz Donna Beer , Zamora Ruben , Vodovotz Yoram , Loughran Patricia A. , Billiar Timothy R. , Kim Young-Myeong , Simmons Richard L. , Watkins Simon C.
Published: February 2003

Shock states induce the expression of inducible nitric oxide synthase (iNOS) in both Kupffer cells and hepatocytes in the liver, but little is known about its subcellular localization in these cells. Studies were undertaken to characterize the subcellular location of iNOS in hepatocytes in response to sepsis. By immunofluorescence analysis, intraperitoneal challenge with bacterial lipopolysaccharide induced cytosolic iNOS in Kupffer cells but punctate labeling in hepatocytes. Cultured rat hepatocytes exposed to interferon gamma, interleukin 1, and tumor necrosis factor α showed iNOS protein expression within peroxisomes as early as 4 hours after stimulation, as determined by colabeling for catalase or PMP70. To a lesser extent, iNOS was also observed associated with the plasma membrane and in undefined intracellular aggregates. The nitric oxide synthase (NOS) antagonist l-N-imino-ornithine (l-NIO) did not affect the expression of iNOS within peroxisomes, cytoplasmic aggregates, or cytosol but increased plasma membrane localization of iNOS. Human iNOS transduced into iNOS-null mouse hepatocytes using an adenoviral vector also localized to peroxisomes. The expression of iNOS often resulted in the disappearance of detectable catalase in many hepatocytes. In conclusion, these studies establish the peroxisome as a site of iNOS localization in hepatocytes and show a relationship between iNOS up-regulation and decreased expression of catalase.
Production of a cytochrome P450 2E1 transgenic mouse and initial evaluation of alcoholic liver damage
Authors: Morgan Kengathevy , French Samuel W. , Morgan Timothy R.
Published: February 2003

Hepatic metabolism of ethanol by cytochrome P450 2E1 (CYP2E1) is believed to contribute to alcoholic liver damage. To further evaluate CYP2E1 in alcoholic liver disease, we created a transgenic mouse containing human CYP2E1 complementary DNA (cDNA) under the control of mouse albumin enhancer-promoter. Two experiments were performed. In the first experiment, transgenic and nontransgenic mice were fed normal chow. In the second experiment, transgenic and nontransgenic mice were pair fed a nutritionally complete liquid diet for 16 weeks. The liquid diet contained 30% of calories as ethanol (or dextrose) and 25% of calories as corn oil. Liver damage was assessed by measuring serum alanine aminotransferase (ALT) levels and examining liver histology. Transgenic animals reproduced and were phenotypically normal. Hepatic levels of CYP2E1 messenger RNA (mRNA), protein, and enzyme activity did not differ between chow-fed transgenic and nontransgenic mice. Livers from transgenic mice fed the alcohol diet contained significantly more CYP2E1 protein and enzyme activity than livers from nontransgenic mice fed the same diet. Transgenic mice receiving the alcohol diet had significantly higher serum ALT levels than nontransgenic mice. Histologic examination of the livers showed higher histologic scores in transgenic mice fed ethanol compared with nontransgenic mice fed ethanol. Ballooning hepatocytes were seen in livers from transgenic mice fed ethanol. Apoptosis, as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, did not differ between groups. In conclusion, we have produced a transgenic mouse that expresses human CYP2E1 in the liver. When fed a nutritionally complete alcohol diet, transgenic mice develop more liver damage than nontransgenic mice.
Course of virologic breakthroughs under long-term lamivudine in HBeAg-negative precore mutant HBV liver disease
Authors: Papatheodoridis George V. , Dimou Evangelini , Laras Andreas , Papadimitropoulos Vassilios , Hadziyannis Stephanos J.
Published: February 2003

We studied the course of virologic breakthroughs detected by a quantitative polymerase chain reaction (PCR) assay in 32 of 78 patients with hepatitis B e antigen (HBeAg)-negative precore mutant hepatitis B virus (HBV) chronic liver disease under long-term lamivudine monotherapy. Serum HBV DNA levels were measured every 3 months and on every biochemical breakthrough. YMDD mutants were detected in 30 of the 32 patients with virologic breakthroughs. Among these 32 patients, biochemical remission rate was 44% at 6 months, 21% at 12 months, and 0% at 24 months after the onset of virologic breakthrough. Development of biochemical breakthroughs was associated with a significant increase of serum HBV DNA levels, which exceeded 100,000 copies/mL in 19 of 20 patients (95%) with biochemical breakthroughs and in only 1 of 8 patients (12.5%) remaining in biochemical remission for at least 6 months after the onset of virologic breakthrough (P < .001). Alanine aminotransferase (ALT) level peaked within 0 to 3 months after the onset of biochemical breakthrough and decreased at 6 months but remained abnormal in all but 2 patients. Follow-up liver histologic lesions in patients with biochemical breakthroughs did not differ from baseline findings, although they were significantly improved in patients remaining in virologic and biochemical remission. In conclusion, the frequent emergence of viral resistance under long-term lamivudine monotherapy in HBeAg-negative precore mutant HBV chronic liver disease is followed by increasing viremia levels culminating in the development of biochemical breakthroughs in most cases. ALT activity peaks close to the onset of biochemical breakthrough, decreasing thereafter but remaining persistently abnormal with fluctuating levels.
Androgen receptor exon 1 CAG repeat length and risk of hepatocellular carcinoma in women
Authors: Yu Ming-Whei , Yang Yu-Ching , Yang Shi-Yi , Chang Hung-Chuen , Liaw Yun-Fan , Lin Shi-Ming , Liu Chun-Jen , Lee Shou-Dong , Lin Chih-Lin , Chen Pei-Jer , Lin Shee-Chan , Chen Chien-Jen
Published: February 2003

The androgen receptor (AR) gene is localized on chromosome X, and shorter CAG repeats in exon 1 of the AR gene were recently suggested to increase hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) risk among men. To examine whether the relationship between the AR-CAG repeats and HCC was also evident among women, we conducted a case-control study in Taiwan. The number of AR-CAG repeats was determined for 238 women with HCC and 354 unrelated control subjects (comprising 188 first-degree and 166 nonbiological relatives) selected from female relatives of patients with HCC. Women harboring 2 AR alleles with more than 23 CAG repeats had an increased risk of HCC (age-adjusted odds ratio [OR], 1.82; 95% CI, 1.06-3.14), compared with women with only short alleles or a single long allele. The association between harboring 2 AR alleles containing longer CAG repeats and HCC was more striking among HBV carriers (age-adjusted OR for more than 22 repeats, 2.23; 95% CI, 1.14-4.34) and particularly prominent among HBV carriers under age 53 years (age-adjusted OR, 3.16; 95% CI, 1.13-8.82). When CAG repeats were analyzed as a continuous variable, the increase in HCC risk associated with each incremental repeat in the shorter of 2 alleles in a given genotype was statistically significant among women with a first-degree relative with HCC (age-adjusted OR, 1.18; 95% CI, 1.01-1.37). No such relationship was detected among women without the family history. In conclusion, our observations suggest that the AR-CAG alleles may contribute to HCC predisposition among women through a mechanism different from that for men.
Cyclin kinase inhibitor p21 potentiates bile acid-induced apoptosis in hepatocytes that is dependent on p53
Authors: Qiao Liang , McKinstry Robert , Gupta Seema , Gilfor Donna , Windle Jolene J. , Hylemon Philip B. , Grant Steven , Fisher Paul B. , Dent Paul
Published: February 2003

Prolonged activation of the mitogen-activated protein kinase (MAPK) pathway enhances expression of the cyclin kinase inhibitor p21 that can promote growth arrest and cell survival in response to cytotoxic insults. Bile acids can also cause prolonged MAPK activation that is cytoprotective against bile acid-induced cell death. Here, we examined the impact of bile acid-induced MAPK signaling and p21 expression on the survival of primary mouse hepatocytes. Deoxycholic acid (DCA) caused prolonged activation of the MAPK pathway that weakly enhanced p21 protein expression. When DCA-induced MAPK activation was blocked using MEK1/2 inhibitors, both hepatocyte viability and expression of p21 were reduced. Surprisingly, constitutive overexpression of p21 in p21+/+ hepatocytes enhanced DCA-induced cell killing. In agreement with these findings, treatment of p21−/− hepatocytes with DCA and MEK1/2 inhibitors also caused less apoptosis than observed in wild-type p21+/+ cells. Expression of p21 in p21−/− hepatocytes did not modify basal levels of apoptosis but restored the apoptotic response of p21−/− cells to those of p21+/+ cells overexpressing p21. These findings suggest that basal expression of p21 plays a facilitating, proapoptotic role in DCA-induced apoptosis. Overexpression of p21 enhanced p53 protein levels. In agreement with a role for p53 in the enhanced apoptotic response, overexpression of p21 did not potentiate apoptosis in p53−/− hepatocytes but, instead, attenuated the death response in these cells. In conclusion, our data suggest that overexpression of p21 can promote apoptosis, leading to elevated sensitivity to proapoptotic stimuli.
Differential regulation of cyclins D1 and D3 in hepatocyte proliferation
Authors: Rickheim David G. , Nelsen Christopher J. , Fassett John T. , Timchenko Nikolai A. , Hansen Linda K. , Albrecht Jeffrey H.
Published: February 2003

Substantial evidence suggests that cyclin D1 plays a pivotal role in the control of the hepatocyte cell cycle in response to mitogenic stimuli, whereas the closely related protein cyclin D3 has not been extensively evaluated. In the current study, we examined the regulation of cyclins D1 and D3 during hepatocyte proliferation in vivo after 70% partial hepatectomy (PH) and in culture. In contrast to cyclin D1, which was nearly undetectable in quiescent liver and substantially up-regulated after PH, cyclin D3 was constitutively expressed and induced only modestly. In the regenerating liver, the concentration of cyclin D3 was only about 10% of that of cyclin D1. Cyclin D1 formed complexes primarily with cyclin-dependent kinase 4 (cdk4), which were markedly activated in the regenerating liver and readily sequestered the cell cycle inhibitory proteins, p21 and p27. Cyclin D3 bound to both cdk4 and cdk6. Cyclin D3/cdk6 activity was readily detectable in quiescent liver and changed little after PH, and this complex appeared to play a minor role in sequestering p21 and p27. In cultured hepatocytes, epidermal growth factor or insulin had little effect, but the combination of these agents substantially induced cyclin D1 and cell cycle progression. Inhibition of Mek1 or phosphoinositide 3-kinase markedly inhibited cyclin D1 expression and replication. In contrast, cyclin D3 was expressed in the absence of mitogens and was only modestly affected by these manipulations. In addition, growth-inhibitory extracellular matrix conditions inhibited cyclin D1 but not cyclin D3 expression. In conclusion, these results support the concept that cyclin D1 is critically regulated by extracellular stimuli that control proliferation, whereas cyclin D3 is regulated through different pathways and plays a distinct role in the liver.
Mrp2 modulates the activity of chloride channels in isolated hepatocytes
Authors: Li Xinhua , Weinman Steven A.
Published: February 2003

Adenosine triphosphate binding cassette family transport proteins are important organic ion transporters in hepatocytes but these molecules may also exhibit other functions. In the present study we have measured the effects of substrates of the canalicular organic ion transporter multidrug resistance associated protein 2 (Mrp2) on chloride channel activation and cell volume regulation. We found that substrates such as leukotriene D4, 17-β-estradiol glucuronide, and the leukotriene inhibitor MK-571 accelerated the activation of chloride channels by cell swelling and activated chloride channels in cytokine-pretreated hepatocytes. Two conjugated estrogens that are not Mrp2 substrates did not produce this effect. Hepatocytes derived from a strain of transport-deficient rats (TR−), which lack Mrp2 expression, showed none of these substrate effects. Coincident with their ability to activate channels, the Mrp2 substrates increased the rate of volume regulatory decrease by approximately 50% (P < .01), confirming that enhanced channel activation under this condition stimulated volume regulation. In TR-hepatocytes the Mrp2 substrate had no effect on volume regulation. In conclusion, Mrp2 plays a role in regulation of chloride channel function by reducing the lag time necessary for channel activation and consequently accelerating the process of cell volume regulation. Substrates of Mrp2 affect the ability of the protein to interact with chloride channels. These findings represent an alternative function of Mrp2 in hepatocytes.
Clinical utility of total HCV core antigen quantification: A new indirect marker of HCV replication
Authors: Bouvier-Alias Magali , Patel Keyur , Dahari Harel , Beaucourt Stéphanie , Larderie Patrick , Blatt Lawrence , Hezode Christophe , Picchio Gaston , Dhumeaux Daniel , Neumann Avidan U. , McHutchison John G. , Pawlotsky Jean-Michel
Published: February 2003

Hepatitis C virus (HCV) RNA detection, viral load quantification, and HCV genotyping are widely used in clinical practice. Recently, the availability of an anticore antigen (Ag) monoclonal antibody allowed development of an enzyme-linked immunosorbent assay (ELISA) detecting and quantifying total HCV core Ag in peripheral blood of HCV-infected patients. The aims of the present study were to investigate the biologic significance of this new marker in HCV infection, to establish the intrinsic performance of the current assay, and to determine its potential utility in the management of HCV-infected patients. A panel of infected sera calibrated to the World Health Organization International Standard and 657 serum samples from infected patients receiving antiviral treatment were studied. We showed that total HCV core Ag quantification is an accurate, precise, and specific indirect marker of HCV replication. We estimated that 1 pg/mL of total HCV core Ag is equivalent to approximately 8,000 HCV RNA international units (IU)/mL, although minor between-patient differences may exist. In conclusion, total HCV core Ag quantification can be used in the various indications of viral load monitoring, including the evaluation of baseline viral load before therapy, the assessment of the virologic response to antiviral treatment, and the study of early viral kinetics during therapy. Nevertheless, the total HCV core Ag assay cannot be used as a marker of viral replication for HCV RNA values below 20,000 IU/mL, limiting its use in the monitoring of late events during and after antiviral treatment.
Repeated fasting stress causes activation of mitogen-activated protein kinases (ERK/JNK) in rat liver
Authors: Nishio Hajime , Kuwabara Hiroko , Mori Hiroshi , Suzuki Koichi
Published: February 2003

Mitogen-activated protein kinases (MAPK)-signaling pathways play key roles in cytoplasmic-nuclear signal transmission in response to various extracellular stimuli. In this study, we investigated the effect of repeated fasting stress on activation of the 3 members of the MAPK family, the extracellular signal-regulated kinase (ERK), the c-Jun NH2-terminal kinase (JNK), and the p38 mitogen-activated protein kinase (p38 kinase), in rat liver. Immunecomplex kinase assays showed that ERK and JNK were significantly activated in the liver extract from fasted rats whereas p38 kinase showed no activation. In an immunohistochemical study, the phosphorylated and activated form of ERK (p-ERK) was abundantly expressed in pericentral hepatocytes of fasted liver compared with those of the control. On the other hand, the phosphorylated and activated form of JNK (p-JNK) was highly expressed in irregular-shaped cells along the sinusoidal lining of fasted liver. A double immunofluorescent study to identify p-JNK immunoreactive cells revealed them to be Kupffer cells, which are the resident hepatic macrophages. In conclusion, ERK and JNK are selectively activated in distinct cell types of rat liver by repeated fasting stress.
Interactions of rifamycin SV and rifampicin with organic anion uptake systems of human liver
Authors: Vavricka Stephan R. , Van Montfoort Jessica , Ha Huy Riem , Meier Peter J. , Fattinger Karin
Published: February 2003

The antibiotics rifamycin SV and rifampicin substantially reduce sulfobromophthalein (BSP) elimination in humans. In rats, rifamycin SV and rifampicin were shown to interfere with hepatic organic anion uptake by inhibition of the organic anion transporting polypeptides Oatp1 and Oatp2. Therefore, we investigated the effects of rifamycin SV and rifampicin on the OATPs of human liver and determined whether rifampicin is a substrate of 1 or several of these carriers. In complementary RNA (cRNA)-injected Xenopus laevis oocytes, rifamycin SV (10 μmol/L) cis-inhibited human organic anion transporting polypeptide C (SLC21A6) (OATP-C), human organic anion transporting polypeptide 8 (SLC21A8) (OATP8), human organic anion transporting polypeptide B (SLC21A9) (OATP-B), and human organic anion transporting polypeptide A (SLC21A3) (OATP-A) mediated BSP uptake by 69%, 79%, 89%, and 57%, respectively, as compared with uptake into control oocytes. In the presence of 100 μmol/L rifamycin SV, BSP uptake was almost completely abolished. Approximate Ki
values were 2 μmol/L for OATP-C, 3 μmol/L for OATP8, 3 μmol/L for OATP-B and 11 μmol/L for OATP-A. Rifampicin (10 μmol/L) inhibited OATP8-mediated BSP uptake by 50%, whereas inhibition of OATP-C-, OATP-B-, and OATP-A-mediated BSP transport was below 15%. 100 μmol/L rifampicin inhibited OATP-C- and OATP8-, OATP-B- and OATP-A-mediated BSP uptake by 66%, 96%, 25%, and 49%, respectively. The corresponding Ki
values were 17 μmol/L for OATP-C, 5 μmol/L for OATP8, and 51 μmol/L for OATP-A. Direct transport of rifampicin could be shown for OATP-C (apparent Km
value 13 μmol/L) and OATP8 (2.3 μmol/L). In conclusion, these results show that rifamycin SV and rifampicin interact with OATP-mediated substrate transport to different extents. Inhibition of human liver OATPs can explain the previously observed effects of rifamycin SV and rifampicin on hepatic organic anion elimination.
Embryoid-body cells derived from a mouse embryonic stem cell line show differentiation into functional hepatocytes
Authors: Chinzei Ryoko , Tanaka Yujiro , Shimizu-Saito Keiko , Hara Yuzuru , Kakinuma Sei , Watanabe Mamoru , Teramoto Kenichi , Arii Shigeki , Takase Kozo , Sato Chifumi , Terada Naohiro , Teraoka Hirobumi
Published: February 2003

Embryonic stem (ES) cells have a potential to differentiate into various progenitor cells. Here we investigated the differentiation capacity of mouse ES cells into hepatocytes both in vitro and in vivo. During the culture of embryoid bodies (EBs) derived from ES cells, albumin (ALB) messenger RNA (mRNA) was expressed within 12 days after removal of leukemia inhibitory factor, and α-fetoprotein (AFP) mRNA was observed within 9 days without additional exogenous growth factors. In ES cells and early EBs, by contrast, neither ALB mRNA nor AFP mRNA was observed. ALB protein was first detected at day 15 and the level increased with the culture period. The differentiation of EBs facilitated the synthesis of urea with the culture period, whereas early EBs and ES cells produced no urea. These results suggest that cultured EBs contain hepatocytes capable of producing ALB and urea. ES cells and the isolated cells from EBs were transplanted through portal vein to the liver after 30% partial hepatectomy of female mice pretreated with 2-acetylaminofluorene. Four weeks after transplantation with isolated cells from day-9 EBs, ES-derived cells containing Y-chromosome in the liver were positive for ALB (0.2% of total liver cells), whereas teratoma was found in mice transplanted with ES cells or EBs up to day 6. The incidence of teratoma was decreased with the culture duration and no teratoma was observed in the liver transplanted with isolated cells from day-9 EBs. In conclusion, our in vitro and in vivo experiments revealed that cultured EBs contain functional hepatocytes or hepatocyte-like cells. (Hepatology 2002;36:22-29.)
Nitric oxide in liver transplantation: Pathobiology and clinical implications
Authors: Shah Vijay , Kamath Patrick S.
Published: February 2003

The gaseous molecule nitric oxide is involved in a variety of liver transplant-relevant processes, including ischemia-reperfusion injury, acute cellular rejection, and circulatory changes characteristic of advanced liver disease. This review article focuses on new advances relating to the role of nitric oxide in these syndromes with an emphasis on pathobiology and potential clinical implications.
Lack of antiviral effect of a short course of mycophenolate mofetil in patients with chronic hepatitis C virus infection
Authors: Firpi Roberto J. , Nelson David R. , Davis Gary L.
Published: February 2003

Mycophenolate mofetil (MMF) is an immunosuppressive agent that is widely used in the management of liver transplant recipients. MMF inhibits the inosine monophosphate dehydrogenase that has been shown to have in vitro antiviral properties against flaviviruses, suggesting the possibility that it might also inhibit the hepatitis C virus (HCV). The goal of this short-term dose escalation study was to assess the antiviral effects of MMF on HCV replication. Patients with chronic hepatitis C who had not undergone liver transplantation were randomized to 8 weeks of treatment with one of four mycophenolate dose regimens (1000 mg orally twice daily, 500 mg orally twice daily, 250 mg orally twice daily, or a matched oral placebo twice daily). All groups were double-blinded. Quantitative HCV RNA levels and serum alanine aminotransferase were assessed at baseline, at weeks 2, 4, and 8 of dosing, and at weeks 4 and 8 of follow-up. Thirty patients met inclusion criteria, enrolled, and were randomized. HCV RNA levels did not change significantly during treatment. Specifically, no subject became virus negative or had a one-log decrease in virus level. Serum aminotransferase level did not normalize in any subject. The most common side effects were headache, nausea, and diarrhea. Mycophenolate alone does not appear to have a significant antiviral or biochemical effect in patients with chronic hepatitis C.
Systemic and regional changes in plasma endothelin following transient increase in portal pressure
Authors: Kapoor Dharmesh , Redhead Doris N. , Hayes Peter C. , Webb David J. , Jalan Rajiv
Published: February 2003

An acute increase in portal pressure or reduction in portal inflow has been shown to decrease renal plasma flow (RPF). The aim of the study was to evaluate regional and systemic hemodynamics after acute occlusion of a transjugular intrahepatic portosystemic stent-shunt (TIPSS) and study the effect of the same on plasma endothelin (ET-1) levels in the systemic circulation, renal vein, and hepatic vein. Sixteen patients attending for portography after previous TIPSS placement were studied. The shunt was acutely occluded with an angioplasty balloon for 12 minutes. Changes in portal pressure gradient (PPG), hepatic plasma flow (HPF), RPF, cardiac output (CO), and systemic vascular resistance (SVR) were measured before and after shunt occlusion. Blood was collected from the femoral artery and hepatic and renal veins for ET-1 measurement. At T = 0, SVR correlated with circulating arterial ET-1 level (r = 0.74; P < .05). After shunt occlusion (T = 12 minutes), heart rate, CO, and mean arterial pressure decreased (P < .05), whereas PPG increased (P < .05). RPF decreased from 485 ± 55 to 282 ± 47 mL/min (P < .01), whereas HPF increased from 700 ± 39 to 779 ± 33 mL/min (P < .001). There was a significant increase in arterial concentration and renal production, and decrease in hepatic production of ET-1. Veno-arterial (V-A) concentration difference in ET-1 level in the renal vein, as well as renal flux of ET-1, increased significantly, whereas hepatic vein V-A concentration difference and hepatic flux of ET-1 decreased significantly. At T = 12 minutes, ET-1 renal output correlated negatively with RPF (r = 0.72; P < .05). Results of this study show that an acute increase in portal pressure and reduction in portal inflow brought about by occlusion of a TIPSS shunt decreases RPF and increases HPF. These hemodynamic changes are accompanied by increases in arterial, renal vein, and hepatic vein ET-1 concentrations, which may possibly mediate the observed findings.
The Ishiguro Extension Block Technique for the Treatment of Mallet Finger Fracture: Indications and Clinical Results
Authors: PEGOLI L. , TOH S. , ARAI K. , FUKUDA A. , NISHIKAWA S. , VALLEJO I. G.
Published: February 2003

The results of extension block Kirschner wire fixation for the treatment of mallet fractures of the distal phalanx were retrospectively assessed in 65 consecutive patients. The indications for this technique were the presence of a large bone fragment, and palmar subluxation or the loss of joint congruity of the distal interphalangeal joint. Using the Wehbé and Scheider classification there were 27 type IB, 19 type IIB, 17 type IA, and 2 type IIA fractures. According to the Crawford rating system there were 46% excellent, 32% good, 20% fair and 2% poor results. We believe that this technique, when properly applied, produces satisfactory results.
Fate of Failed Meuli Total Wrist Arthroplasty
Authors: VÖGELIN ESTHER , NAGY LADISLAV
Published: February 2003

Sixteen Meuli wrist arthroplasties in 13 patients suffering mainly from rheumatoid arthritis were revised for failure. Causes for failure were mechanical problems with the implant in three wrists, soft tissue problems in two wrists and a combination of mechanical failure and soft tissue problems in 11 wrists. Management included 11 revision arthroplasties in ten wrists, four arthrodeses and two primary soft tissue reconstructions. Twenty-six additional soft tissue procedures were required in association with the revision arthroplasties or arthrodeses. Five of the 11 revision arthroplasties had to be converted to arthrodeses after an average of 5 (range 3–8) years. After removal of a failed wrist implant union of the salvage arthrodesis was diffcult to achieve in two of the nine instances. This series demonstrates that revision arthroplasty may be a useful alternative to arthrodesis for the salvage of primary wrist arthroplasties in rheumatoid patients. However, complications and reoperations may occur after both revision arthroplasty and arthrodesis.
Osteochondral Grafting of the Metacarpophalangeal Joint in Rheumatoid Arthritis
Authors: LO C. Y. , CHANG Y. P.
Published: February 2003

We report two cases of isolated metacarpophalangeal joint subluxation in rheumatoid patients with dorsal osteochondral defects on the base of the proximal phalanx. These were treated by open reduction, autologous osteochondral grafting and synovectomy. Stable reduction was maintained and appeared to delay the deterioration of the joint.
Dupuytren’s Disease Affecting the Thumb and First Web of the Hand
Authors: MILNER R. H.
Published: February 2003

The clinical distribution of the Dupuytren’s disease cords in the thumb and first web was examined in 100 consecutive patients with Dupuytren’s disease. The precise anatomical relations of the cords were then studied in 25 patients undergoing Dupuytren’s surgery for thumb and first web space disease. Thumb and first web space involvement was found in 28% of hands affected by Dupuytren’s disease, and was the third most common site after the ring and little fingers. Operative findings showed that two major cords could be distinguished. One lying in the first web space and passing towards the insertion of the first dorsal interosseous muscle on the radial side of the index finger and the other lying on the radial aspect of the thumb.
Intramuscular Tenotomy of Flexor Digitorum Superficialis in the Distal Forearm After Surgical Excision of Dupuytren’s Disease
Authors: BARR V. , BHATIA R. , HAWKINS P. , SAVAGE R.
Published: February 2003

Contracture of the proximal interphalangeal joint after surgery to excise Dupuytren’s disease, despite release of the contributory structures within the finger, can be caused by flexor digitorum superficialis (FDS) contracture. We describe five cases where FDS contracture was released by intramuscular tenotomy in the distal forearm. Standard postoperative therapy for Dupuytren’s fasciectomy was used and clinical review showed improved finger extension with no loss of strength. We suggest that intramuscular tenotomy of FDS in the forearm can be used safely where indicated after excision of the Dupuytren’s disease.
Hemiarthroplasty for Trapeziometacarpal Arthritis – A Useful Alternative?
Authors: PHALTANKAR P. M. , MAGNUSSEN P. A.
Published: February 2003

We performed hemiarthroplasty using the Swanson titanium implant for treatment of isolated and advanced trapeziometacarpal joint osteoarthritis Nineteen implants were placed in 18 patients (mean age: 57 years) between 1995 and 1999. One joint required revision and conversion to trapeziectomy. Eighteen joints in 17 patients were evaluated with a mean follow-up period of 34 (range, 14–60) months. Good pain relief was noted in 13 hands. All patients had good hand function as scored using validated questionnaires. Radiographic loosening occurred with five implants and trapezial wear in ten joints. Though radiographic loosening or trapezial wear did not correlate with less satisfactory clinical results, failure of the implant is a concern in the long term. Preliminary results indicate that hemiarthroplasty can be a useful treatment alternative in selected, relatively young patients with isolated trapeziometacarpal osteoarthritis and good bone stock. Good motion and stability can be preserved Failures can be effectively salvaged by trapeziectomy.
Anterolateral Thigh Free Flap for Complex Soft Tissue Hand Reconstructions
Authors: JAVAID M. , CORMACK G. C.
Published: February 2003

The anterolateral thigh free flap is described in terms of its surgical anatomy, techniques of elevation and its application in seven cases of trauma to the hand. The particular advantages of this free flap for reconstructing a variety of hand defects are demonstrated. Flap refinements that have potential applications for hand surgery are described.
The Two-Level Ulnar Collateral Ligament Injury of the Metacarpophalangeal Joint of the Thumb
Authors: GIELE H. , MARTIN J.
Published: February 2003

Ulnar collateral ligament injuries of the thumb may present as avulsion fractures of the bone or as ligamentous tears. Displaced fracture fragments or Stener lesions demand operative management. Occasionally, both fracture and ligamentous tears may occur simultaneously, and the management of the ligamentous aspect may be overlooked in cases with undisplaced fractures leading to failure of non-operative treatment. It is important in cases with a relatively undisplaced fracture fragment to exclude a simultaneous ligamentous tear and Stener lesion by careful clinical examination and by examining the radiographs for telltale displaced flecks of bone.