bluuebunny/crossref_metadata_2025 huggingface dataset:
Cannabinoids and neuroinflammation
Authors: Walter Lisa , Stella Nephi
Published: March 2004

Growing evidence suggests that a major physiological function of the cannabinoid signaling system is to modulate neuroinflammation. This review discusses the anti‐inflammatory properties of cannabinoid compounds at molecular, cellular and whole animal levels, first by examining the evidence for anti‐inflammatory effects of cannabinoids obtained using in vivo animal models of clinical neuroinflammatory conditions, specifically rodent models of multiple sclerosis, and second by describing the endogenous cannabinoid (endocannabinoid) system components in immune cells. Our aim is to identify immune functions modulated by cannabinoids that could account for their anti‐inflammatory effects in these animal models.

British Journal of Pharmacology (2004) 141, 775–785. doi:10.1038/sj.bjp.0705667
Overexpression of β1‐adrenoceptors in adult rat ventricular myocytes enhances CGP 12177A cardiostimulation: implications for ‘putative’β4‐adrenoceptor pharmacology
Authors: Lewis Clive J , Gong Haibin , Brown Morris J , Harding Sian E
Published: March 2004

CGP 12177A mediates cardiostimulation by activation of the ‘putative’ β4‐adrenoceptor; however, it has recently been reported that disruption of the β1‐adrenoceptor gene abolishes this effect. We have adenovirally overexpressed β1‐adrenoceptors in isolated, cultured adult rat ventricular cardiomyocytes and observed the inotropic potency of isoprenaline and CGP 12177A (in the presence of 1 μM propranolol).

Isoprenaline was a full inotropic agonist at rat ventricular myocytes (pD2 7.69±0.12). CGP 12177A was a nonconventional partial agonist (pD2 6.34±0.09), increasing inotropy and lusitropy, with an intrinsic activity of 0.34 and antagonised by bupranolol.

β1‐adrenoceptor overexpression enhanced the inotropic potency of isoprenaline by 11.7‐fold (pD2 8.76±0.14) and CGP 12177A by 5.9‐fold (7.11±0.10), respectively. Green fluorescent protein (GFP) overexpression did not alter the potency of isoprenaline or CGP 12177A (pD2 7.41±0.24 and pD2 6.60±0.50, respectively).

The cardiostimulant effects of CGP 12177A were enhanced by IBMX (phosphodiesterase inhibitor) and decreased by Rp‐cAMPS (cAMP antagonist). CGP 12177A also increased cAMP levels. CGP 12177A but not isoprenaline initiated arrhythmias at lower concentrations following β1‐adrenoceptor overexpression.

125I‐Cyanopindolol saturation binding in Adv.β1 myocytes demonstrated ∼18‐fold increase in β1‐adrenoceptors. 3H‐CGP 12177A saturation binding, in the presence of propranolol, increased ∼5‐fold following overexpression of β1‐adrenoceptors.

This study demonstrates enhanced cardiostimulation by CGP 12177A (in the presence of propranolol) in rat ventricular myocytes overexpressing β1‐adrenoceptors, mediated by a Gs/cAMP signalling pathway. ‘Putative’ β4‐adrenoceptor pharmacology appears to be mediated by activation of a novel affinity state of the β1‐adrenoceptor.

British Journal of Pharmacology (2004) 141, 813–824. doi:10.1038/sj.bjp.0705668
Molecular analysis of the subtype‐selective inhibition of cloned KATP channels by PNU‐37883A
Authors: Kovalev H , Quayle J M , Kamishima T , Lodwick D
Published: March 2004

In this study, we have used Kir6.1/Kir6.2 chimeric proteins and current recordings to investigate the molecular basis of PNU‐37883A inhibition of cloned KATP channels.

Rat Kir6.1, Kir6.2 and Kir6.1/Kir6.2 chimeras were co‐expressed with either SUR2B or SUR1, following RNA injection into Xenopus oocytes, and fractional inhibition of KATP currents by 10 μM PNU‐37883A reported.

Channels containing Kir6.1/SUR2B were more sensitive to inhibition by PNU‐37883A than those containing Kir6.2/SUR2B (mean fractional inhibition: 0.70, cf. 0.07).

On expression with SUR2B, a chimeric channel with the Kir6.1 pore and the Kir6.2 amino‐ and carboxy‐terminal domains was PNU‐37883A insensitive (0.06). A chimera with the Kir6.1 carboxy‐terminus and Kir6.2 amino‐terminus and pore was inhibited (0.48). These results, and those obtained with other chimeras, suggest that the C‐terminus is an important determinant of PNU‐37883A inhibition of Kir6.1. Similar results were seen when constructs were co‐expressed with SUR1. Further chimeric constructs localised PNU‐37883A sensitivity to an 81 amino‐acid residue section in the Kir6.1 carboxy‐terminus.

Our data show that structural differences between Kir6.1 and Kir6.2 are important in determining sensitivity to PNU‐37883A. This compound may prove useful in probing the structural and functional differences between the two channel subtypes.

British Journal of Pharmacology (2004) 141, 867–873. doi:10.1038/sj.bjp.0705670
Regulation of microglial inflammatory response by sodium butyrate and short‐chain fatty acids
Authors: Huuskonen Jari , Suuronen Tiina , Nuutinen Tapio , Kyrylenko Sergiy , Salminen Antero
Published: March 2004

Recent studies have shown that sodium butyrate and other short‐chain fatty acids (SCFAs) can prevent inflammation in colon diseases. Our aim was to elucidate whether sodium butyrate and SCFAs regulate the inflammatory responses in different neural inflammation models in cell cultures.

Inflammatory responses to LPS‐induced microglial activation were recorded by the secretion of nitric oxide (NO) and cytokines IL‐6 and TNF‐α and related to the changes in the DNA‐binding activities of NF‐κB complex.

We observed that sodium butyrate is strongly anti‐inflammatory against LPS‐induced responses in rat primary microglia as well as in hippocampal slice cultures and in neural cocultures of microglial cells, astrocytes and cerebellar granule neurons.

In murine N9 microglial cell line, instead, sodium butyrate and other SCFAs (propionate, valerate and caproate) enhanced the LPS‐induced inflammatory response.

The pretreatment with butyrate before LPS exposure induced an equal or more enhanced response than simultaneous exposure with butyrate and LPS. This indicates that butyrate induces an adaptative response against microglial activation.

We also observed that butyrate treatment both in transformed N9 cells and in hippocampal slice cultures downregulates the NF‐κB‐binding capacity induced by LPS stimulation.

Our results show that butyrate is anti‐inflammatory in primary, brain‐derived microglial cells, as observed recently in colon diseases, but proinflammatory in transformed, proliferating N9 microglial cells, which may be related to the anticancer properties of butyrate observed in tumor cells.

British Journal of Pharmacology (2004) 141, 874–880. doi:10.1038/sj.bjp.0705682
Impact of stocking on yield in small reservoirs in Andhra Pradesh, India
Authors: Sugunan V. V. , Katiha P. K.
Published: March 2004

The relationships between surface area, stocking density and fish yield in 40 small reservoirs in India between 1994 and 1999 were examined. A significant positive correlation (r = 0.6) was found between stocking density and fish yield. Area was negatively correlated with stocking density (r = −0.57) and fish yield (r = −0.62), but its correlation with efficiency of stocking was not significant for all the size groups of small reservoirs.
The nocturnal secretion of cardiac natriuretic peptides during obstructive sleep apnoea and its response to therapy with nasal continuous positive airway pressure
Authors: KITA HIDEO , OHI MOTOHARU , CHIN KAZUO , NOGUCHI TETSUO , OTSUKA NAOKI , TSUBOI TOMOMASA , ITOH HIROSHI , NAKAO KAZUWA , KUNO KENSHI
Published: March 2004

The nocturnal secretion profile of the newly identified natriuretic peptide (NP), brain natriuretic peptide (BNP), was studied in 14 patients with obstructive sleep apnoea syndrome (OSAS) (apnoea hypopnoea index: 60.5±3.4, mean±SE) during two separate nights before and during nasal continuous positive airway pressure (NCPAP) therapy. Plasma levels of NPs (atrial natriuretic peptides; ANP and BNP) were measured at 2‐h intervals during sleep. Simultaneously, blood pressure was measured by a non‐invasive method (Finapres®, Ohmeda, Englewood, CO, USA) and urine was collected for determing volume and catecholamine levels. Urinary and serum sodium concentration were determined before and after the study. Eight non‐snoring subjects were also studied for the investigation of normal nocturnal profiles of BNP levels. To understand the discrete secretion profiles of the two NPs during sleep, blood was sampled from an additional seven patients every 5 min over a 30‐min period around 00.00 and 04.00 hours before NCPAP. In patients with OSAS, plasma BNP levels increased from the beginning of sleep (22:00 h) to the morning (06:00 h) before NCPAP therapy (P< 0.01, anova). Baseline BNP levels were not significantly correlated with patient's clinical and poly‐ somnographic parameters. However, in the latter half of the sleep period (02:00–06:00 h), increases in BNP levels during the night before NCPAP therapy were significantly correlated with blood pressure elevations (systolic: r=0.784 P< 0.01, diastolic: r=0.587 P< 0.01) and with apnoea duration (r=0.582 P< 0.01). In normal subjects BP and BNP levels were not changed significantly during sleep. Plasma BNP levels were well correlated with concomitant ANP levels (P< 0.001). NCPAP therapy reduced ANP and BNP levels during sleep and in the morning (P< 0.01). Plasma levels of BNP at 5 min intervals before NCPAP therapy revealed few variations. On the other hand, ANP levels fluctuated over the 30‐min period. Changes in BNP levels during sleep in the patients with OSAS may be related to blood pressure variations, but may be too small to play a significant physiological role in regulating diuresis in OSAS. Further work is required to determine the precise role of dual natriuretic system in cardiovascular load and natriuresis in OSAS.
Blood pressure effects of long‐term stimulant use in disorders of hypersomnolence
Authors: WALLIN MITCHELL , MAHOWALD MARK
Published: March 2004

Untoward cardiovascular effects have been implicated as a deterrent to long‐term central nervous system (CNS) stimulant use in disorders of hypersomnolence. In this study, we reviewed the relationship between blood pressure and long‐term stimulant use. Medical records of 54 patients with narcolepsy and idiopathic CNS hyper‐ somnolence (ICH) were reviewed. The overall mean number of months of follow‐up for the entire group was 45.6 (95% CI: 42–49). Both simple linear regression and multiple regression utilizing generalized estimating equations were used to show relationships between blood pressure (BP), time and other covariates. In the simple linear regression model, the average slope of the line of systolic BP (SBP) on time for the entire group was 0.06 (95% CI: ‐0.09, 0.13) and the line of diastolic BP (DBP) on time was 0.01 (95% CI: ‐0.05, 0.07). Two multiple regression equations were fitted for the continuous response variables SBP and DBP. Covariates in the model included: time, hypertension, weight at baseline, weight, SBP baseline (SBPBL), DBP baseline (DBPBL), high vs. low dose stimulant therapy and age at starting treatment. For SBP, the covariates weight at baseline, weight and SBPBL were significant (P< 0.05) predictors. For DBP, covariates reaching statistical significance (P< 0.05) included weight and DBPBL. There was no significant change in SBP or DBP over time in either model. Two different statistical models support the conclusion that there was no significant change in SBP or DBP over time in this population.
Stratigraphy, sedimentology, structure and tectonics of Lower Ordovician and Devonian strata of South Mootwingee, Darling Basin, western New South Wales
Authors: Neef G.
Published: March 2004

A small inlier of marine Bynguano Quartzite, of Early Ordovician age, was discovered in the eastern part of the mapped area, although most of the strata are Devonian in age. The mid‐Emsian to mid‐Eifelian Snake Cave Sandstone consists of seven informal units. In the west the Waverly Creek Formation (new) is unconformable on the Snake Cave Sandstone; it consists of The Rocky Tank Conglomerate Member (new) (?early Givetian in age), which is overlain by the Ramparts Creek Sandstone Member (new) (mid‐Givetian in age). In the west the late Givetian to Famennian Ravendale Formation is conformable on the Ramparts Creek Sandstone Member whereas further east where the Waverly Creek Formation is absent, the Ravendale Formation is largely paraconformable on Snake Cave Sandstone. The area is cut by the north‐northwest‐trending Mootwingee (in the west) and the Boorungie Faults (in the east). These faults were active during the Tabberabberan and the Kanimblan Orogenic Pulses of the Lachlan Orogen and they subdivide the area into West, Central and East Blocks. The West and the Central Blocks are an uplifted part of the Bancannia Trough (basin inversion) whereas the East Block is a southern part of the Wonominta Block.
Preconditioning protects liver and lung damage in rat liver transplantation: Role of xanthine/xanthine oxidase
Authors: Fernández Leticia , Heredia Nicolás , Grande Luis , Gómez Gloria , Rimola Antonio , Marco Alberto , Gelpí Emilio , Roselló-Catafau Joan , Peralta Carmen
Published: March 2004

This study was designed to evaluate whether ischemic preconditioning could confer protection against liver and lung damage associated with liver transplantation. The effect of preconditioning on the xanthine/xanthine oxidase (XOD) system in liver grafts subjected to 8 and 16 hours of cold ischemia was also evaluated. Increased xanthine levels and marked conversion of xanthine dehydrogenase (XDH) to XOD were observed after hepatic cold ischemia. Xanthine/XOD could play a role in the liver and lung damage associated with liver transplantation. This assumption is based on the observation that inhibition of XOD reduced postischemic reactive oxygen species (ROS) generation and hepatic injury as well as ensuing lung inflammatory damage, including neutrophil accumulation, oxidative stress, and edema formation. Ischemic preconditioning reduced xanthine accumulation and conversion of XDH to XOD in liver grafts during cold ischemia. This could diminish liver and lung damage following liver transplantation. In the liver, preconditioning prevented postischemic ROS generation and hepatic injury as well as the injurious effects in the lung following liver transplantation. Administration of xanthine and XOD to preconditioned rats led to hepatic ROS and transaminase levels similar to those found after reperfusion and abolished the protective effect of preconditioning on the lung inflammatory damage. In conclusion, ischemic preconditioning reduces both liver and lung damage following liver transplantation. This endogenous protective mechanism is capable of blocking xanthine/XOD generation in liver grafts during cold ischemia.
Blockade of the l-arginine/NO synthase pathway worsens hepatic apoptosis and liver transplant preservation injury
Authors: Yagnik Gautam P. , Takahashi Yoshihito , Tsoulfas George , Reid Kaye , Murase Noriko , Geller David A.
Published: March 2004

Organ graft preservation injury is a major problem complicating liver transplantation. The l-arginine/nitric oxide pathway has protective effects in several models of liver injury. The purpose of this study was to evaluate the role of the l-arginine/NO synthase (NOS) pathway on liver preservation injury and to characterize endogenous inducible NOS (iNOS) expression. Orthotopic liver transplantation was performed with 18-hour University of Wisconsin preservation solution in syngeneic rats. Recipient rats were either untreated or treated with l-arginine, d-arginine, nonspecific NOS inhibitor NG
-nitro-l-arginine methyl ester (l-NAME), or iNOS selective inhibitor l-N6
-(1-imino-ethyl)lysine (l-NIL) after revascularization. As early as 1 hour following reperfusion, circulating arginine levels decreased 10-fold and ornithine levels increased 4-fold. A corresponding increase in arginase I protein was detected in serum. To address the profound arginine deficiency, we supplemented recipients with arginine after transplantation. l-arginine (but not d-arginine) supplementation significantly reduced preservation injury 12 hours after reperfusion, suggesting that the protective effect of l-arginine was mediated through the generation of NO. iNOS protein expression peaked in the liver 6 to 12 hours following reperfusion. Blockade of the l-arginine/NO pathway with l-NAME significantly increased necrotic and apoptotic cell death in the transplanted graft. Addition of the iNOS selective inhibitor l-NIL mildly increased liver transaminase levels and also increased apoptosis in the liver graft. In conclusion, transplant recipients are profoundly arginine deficient postreperfusion due to arginase release. l-Arginine supplementation and NO synthesis decrease necrotic and apoptotic cell death and ameliorate liver transplant preservation injury.
Differentiated properties of hepatocytes induced from pancreatic cells
Authors: Tosh David , Shen Chia-Ning , Slack Jonathan M. W.
Published: March 2004

Transdifferentiation of pancreas to liver is a well-recognized phenomenon and has been described in animal experiments and human pathology. We recently produced an in vitro model for the transdifferentiation (or conversion) of the pancreatic cell line AR42J-B13 to hepatocytes based on culture with dexamethasone (Dex). To determine whether the hepatocytes express markers of hepatic intermediary metabolism and detoxification, we investigated the patterns of expression of glucokinase, cytochrome P450s CYP3A1 and CYP2B1/2, testosterone/4-nitrophenol uridine diphosphate glucuronosyltransferase (UDPGT), and aryl sulfotransferase. All were expressed. We also determined the expression of 2 enzymes involved in ammonia detoxification: carbamoylphosphate synthetase I (CPS I) and glutamine synthetase (GS). These enzymes are normally strictly compartmentalized in liver in a wide periportal pattern and the last downstream perivenous hepatocytes, respectively. Following culture with Dex, CPS I and GS are expressed in 2 different cell populations, suggesting that both periportal and perivenous hepatocytes are induced. We also produced a reporter assay based on the activation of green fluorescent protein (GFP) by the transthyretin (TTR) promoter or glucose-6-phosphatase (G6Pase) promoter. After culture with Dex, transfected cells begin to express GFP, showing that hepatic promoters are activated in concert with the induction of the hepatocyte phenotype. Lastly, we examined the stability of the hepatic phenotype and found that some cells still express liver markers (transferrin or albumin) up to 14 days after removal of Dex. In conclusion, these results suggest that pancreatic hepatocytes produced by this method may offer an alternative model to primary cultures of hepatocytes for the study of liver function.
Novel fibrinogen γ375 Arg→Trp mutation (fibrinogen aguadilla) causes hepatic endoplasmic reticulum storage and hypofibrinogenemia
Authors: Brennan Stephen O. , Maghzal Ghassan , Shneider Benjamin L. , Gordon Ronald , Magid Margret S. , George Peter M.
Published: March 2004

The proposita and her sister had chronically elevated liver function test results, and needle biopsy specimens showed scattered eosinophilic inclusions within the hepatocytes. On immunoperoxidase staining, the inclusions reacted strongly with anti-fibrinogen antisera; on electron-microscopic (EM) examination, the material appeared confined to the endoplasmic reticulum (ER) and was densely packed into tubular structures with a swirling fingerprint appearance. Coagulation investigations showed low functional and antigenic fibrinogen concentrations that were indicative of hypofibrinogenemia. Amplification and DNA sequencing showed a heterozygous CGG→TGG mutation at codon 375 of the fibrinogen γ chain gene. This novel γ375 Arg→Trp substitution segregated with hypofibrinogenemia in 3 family members and was absent from 50 normal controls. When purified plasma fibrinogen chains were examined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, reverse-phase chromatography, electrospray ionization mass spectrometry, and isoelectric focusing, only normal γ chains were detected. In conclusion, we propose that this nonconservative mutation causes a conformational change in newly synthesized molecules and that this provokes aggregation within the ER and in turn causes the observed hypofibrinogenemia. Whereas the mutation site, γ375, is located in the γD domain at the jaws of the primary E-to-D polymerization site, purified plasma fibrinogen showed normal polymerization, supporting our contention that molecules with variant chains never reach the circulation but accumulate in the ER.
Steatosis in chronic hepatitis C: Relative contributions of obesity, diabetes mellitus, and alcohol
Authors: Monto Alexander , Alonzo Judy , Watson Jessica J. , Grunfeld Carl , Wright Teresa L.
Published: March 2004

Steatosis has emerged as a histologic finding of importance to the progression of hepatitis C virus (HCV)-associated liver disease. However, most studies of HCV-associated steatosis have excluded alcohol drinkers and individuals with diabetes and thus have not addressed the relative contribution of known causes of steatosis to liver injury in HCV-associated disease. To address this issue, we studied 297 consecutive patients with HCV who met inclusion criteria. Alcohol consumption, demographics, and serologic tests were correlated with degrees of steatosis and fibrosis on liver biopsy. Liver biopsy specimens were also examined for evidence of significant alcohol or nonalcoholic steatohepatitis (NASH) injury. In univariate analysis, steatosis correlated with type 2 diabetes mellitus (P = .005) and body mass index (BMI) (P = .0001) but not with the intensity of alcohol intake (in grams per day). In multivariate analysis, BMI (P = .0002) and genotype 3a infection (P = .02) were independent predictors of steatosis. When patients with risk factors for NASH were excluded, genotype 3a infection was the only independent predictor of steatosis. Steatosis (P = .04) and inflammation (P < .0001) scores on liver biopsy were the only independent predictors of fibrosis. Significant alcohol or NASH injury was found in only 6% of biopsy specimens. In conclusion, steatosis in HCV infection is associated with risk factors for NASH, particularly obesity, rather than alcohol consumption.
Opportunities for prevention: Hepatitis C prevalence and incidence in a cohort of young injection drug users
Authors: Miller Cari L. , Johnston Caitlin , Spittal Patricia M. , Li Kathy , LaLiberté Nancy , Montaner Julio S. G. , Schechter Martin T.
Published: March 2004

The objective of this study was to compare sociodemographic, drug, and sexual risk characteristics between hepatitis C virus (HCV) baseline positive and negative young (13-24 years) injection drug users (IDUs) and to determine prospective risk factors for HCV seroconversion among the youth. Data were collected through the Vancouver Injection Drug Users Study (VIDUS). To date, more than 1,400 Vancouver-area IDUs have been enrolled and followed up; 234 were aged 24 years and younger. Semiannually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for human immunodeficiency virus (HIV) and HCV. Univariate and multivariate logistic regression analyses were undertaken to investigate predictors of baseline HCV positivity. In the multivariate analyses, Cox regression models with time-dependent covariates were used to identify predictors of HCV seroconversion. Of the 232 young injectors, 107 (46%) were HCV positive at baseline and a further 37 HCV seroconverted during the study period for an incidence rate of 37.3 per 100 person-years. Baseline positivity was associated with Aboriginal ancestry, older age, greater number of years injecting drugs, recent incarceration, sex trade work, more than 100 lifetime sexual partners, a previous sexually transmitted disease, living in the IDU epicenter, and injection more than once per day of heroin, cocaine, and speedball. Factors independently associated with HCV seroconversion were having a partner who uses injection drugs, requiring help to inject, and injection of cocaine more than once daily. In conclusion, unlike older IDUs, more than one half of young injectors were HCV negative at recruitment. Thus, there is a window of opportunity for prevention. However, the incidence rate of HCV among these young IDUs is alarming, suggesting that the opportunity to intervene is exceedingly small.
Bacterial motif DNA as an adjuvant for the breakdown of immune self-tolerance to pyruvate dehydrogenase complex
Authors: Jones David E. J. , Palmer Jeremy M. , Burt Alastair D. , Walker Claire , Robe Amanda J. , Kirby John A.
Published: March 2004

Bacterial DNA containing unmethylated CpG dinucleotide motifs is immunostimulatory to mammals, skewing CD4+ T-cell responses toward the Th1 phenotype. Autoreactive T-cell responses seen in primary biliary cirrhosis (PBC) are typically of the Th1 phenotype, raising the possibility that bacterial DNA might play a role in the generation of pathologic autoimmunity. We therefore studied the effects of CpG motif-containing oligodeoxynucleotides (ODN) on responses to pyruvate dehydrogenase complex (PDC, the autoantigen in PBC) in a murine model. Sensitization of SJL/J mice with non-self-PDC has been shown to result in induction of autoreactive T-cell responses to PDC sharing characteristics with those seen in patients with PBC. Administration of CpG ODN to SJL/J mice at the time of sensitization with PDC resulted in a significant skewing of splenic T-cell response to self-PDC, with significant augmentation of the Th1 cytokine response (interleukin [IL] 2 and interferon [IFN] gamma) and reduction of the Th2 response (IL-4 and IL-10). In fact, CpG ODN seemed to be more effective at biasing the response phenotype and as effective at inducing liver histologic change as complete Freund’s adjuvant (CFA), the standard adjuvant used for induction of Th1 responses in murine autoimmune and infectious immunity models. In conclusion, our findings raise the possibility that bacteria play a role in the development of autoimmunity (in PBC at least) through the potential of their DNA to shift the T-cell responses toward the phenotype associated with autoimmune damage. Moreover, this study suggests caution in the therapeutic use of CpG ODN as vaccine adjuvants.
Preemptive use of lamivudine reduces hepatitis B exacerbation after allogeneic hematopoietic cell transplantation
Authors: Lau George K. K. , He Ming-Liang , Fong Daniel Y. T. , Bartholomeusz Angeline , Au Wing-yan , Lie Albert K. W. , Locarnini Stephen , Liang Raymond
Published: March 2004

Exacerbation of hepatitis B virus (HBV) is a serious cause of morbidity and mortality in hepatitis B surface antigen (HBsAg)-positive patients undergoing transplantation. Our aim was to evaluate the effectiveness of lamivudine to prevent hepatitis due to exacerbation of HBV in HBsAg-positive patients treated with allogeneic hematopoietic cell transplantation. We studied 20 consecutive HBsAg-positive recipients of allogeneic hematopoietic cell transplantation who received lamivudine 100 mg daily starting one week before transplantation until week 52 after transplantation (group 1). Serial serum alanine aminotransferase and HBV DNA levels were measured before and after transplantation at 4- to 8-week intervals for the first year and then 4- to 12-week intervals. Their virologic and clinical outcomes were compared with 20 case-matched recipients who did not receive any antiviral therapy to HBV (anti-HBV) before and after hematopoietic cell transplantation (group 2). After transplantation, 9 patients (45%) in group 2 and one patient (5%) in group 1 had hepatitis due to exacerbation of HBV (P < .008), with 3 hepatic failures in group 2 and none in group 1. The one-year actuarial probability of survival without hepatitis due to exacerbation of HBV was higher in group 1 than group 2 (94.1% vs. 54.3%, P = .002). By multivariate Cox analysis, preemptive use of lamivudine effectively reduced hepatitis due to exacerbation of HBV (adjusted hazards ratio, 0.09; P = .021). In conclusion, preemptive lamivudine reduced HBV exacerbation. The use of lamivudine with other immunosuppressive regimens to prevent exacerbation of HBV should be further explored.
Serum phosphate is an early predictor of outcome in severe acetaminophen-induced hepatotoxicity
Authors: Schmidt Lars E. , Dalhoff Kim
Published: March 2004

Hypophosphatemia is frequently observed in acetaminophen-induced hepatotoxicity and may be involved in the pathogenesis of hepatic failure. The aim of the study was to evaluate the prognostic value of serial measurements of serum phosphate in patients with severe acetaminophen poisoning. Prospectively, serial measurements of serum phosphate were performed in 125 patients with severe acetaminophen poisoning. The optimum threshold value of serum phosphate to discriminate nonsurvivors was identified. Prognostic value and speed of identification were compared with those of the King’s College Hospital (KCH) criteria. Phosphate concentrations were significantly higher in nonsurvivors than in survivors at 48 to 72 hours after overdose (mean 2.65 ± 1.18 mmol/L vs. 0.68 ± 0.22 mmol/L, P < .001) as well as 72 to 96 hours after overdose (2.12 ± 0.22 mmol/L vs. 0.59 ± 0.23 mmol/L, P < .001). A threshold phosphate concentration of 1.2 mmol/L at 48 to 96 hours after overdose had sensitivity 89%, specificity 100%, accuracy 98%, positive predictive value 100%, and negative predictive value 98%. The phosphate criteria had higher sensitivity, accuracy, and positive and negative predictive values than the KCH criteria, and it identified patients significantly earlier after transferal [median 1 hour (range 1-38 hours) vs. 12 hours (2-192 hours), P < .05, respectively]. In nonsurvivors, the degree of hyperphosphatemia correlated with renal dysfunction (R = .55; P = .02). In conclusion, hyperphosphatemia after acetaminophen overdose is seen exclusively in nonsurvivors, which makes it a highly specific as well as sensitive predictor of nonsurvival. We propose that hyperphosphatemia is caused by renal dysfunction in the absence of hepatic regeneration, as the latter appears to be associated with lowering of serum phosphate.
Inhibitory activity of dioxolane purine analogs on wild-type and lamivudine-resistant mutants of hepadnaviruses
Authors: Seignères Béatrice , Pichoud Christian , Martin Perrine , Furman Philip , Trépo Christian , Zoulim Fabien
Published: March 2004

To design combination strategies for chronic hepatitis B therapy, we evaluated in vitro the inhibitory activity of 4 nucleoside analogs, (−)FTC, L-FMAU, DXG, and DAPD, in comparison with lamivudine (3TC) and PMEA. In a cell-free assay for the expression of wild-type duck hepatitis B virus (DHBV) reverse transcriptase, DAPD-TP was found to be the most active on viral minus strand DNA synthesis, including the priming reaction, followed by 3TC-TP, (−)FTC-TP, and DXG-TP, whereas L-FMAU-TP was a weak inhibitor. In cell culture experiments, important differences in drug concentration allowing a 50% inhibition of viral replication or polymerase activity (IC50s) were observed depending on the cell type used, showing that antiviral effect of nucleoside analogs may depend on their intracellular metabolism. IC50s obtained for wild-type DHBV replication in primary duck hepatocytes were much lower than with DHBV transfected LMH cells. IC50s were also significantly lower in the 2.2.1.5 and HepG2 cells compared with HBV transfected HuH7 cells. Moreover, L-FMAU inhibited preferentially HBV plus strand DNA synthesis in these cell lines. The antiviral effect of these inhibitors was also evaluated against 3TC-resistant mutants of the DHBV and HBV polymerases. These mutants were found to be cross resistant to (−)FTC. By contrast, the double DHBV polymerase mutant was sensitive to DXG-TP and DAPD-TP. Moreover, both purine analogs remained active against DHBV and HBV 3TC-resistant mutants in transfected LMH and HepG2 cells, respectively. In conclusion, the unique mechanism of action of these new inhibitors warrants further evaluation in experimental models to determine their capacity to delay or prevent the selection of drug resistant mutants.
A randomized placebo-controlled study of long-acting octreotide for the treatment of advanced hepatocellular carcinoma
Authors: Yuen Man-Fung , Poon Ronnie Tung-Ping , Lai Ching-Lung , Fan Sheung-Tat , Lo Chung-Mau , Wong Ka-Wah , Wong Wai Man , Wong Benjamin Chun-Yu
Published: March 2004

Although various types of treatment of hepatocellular carcinoma (HCC) have been tried, the prognosis remains dismal, especially in patients with advanced stage of the disease. Somatostatin analogues exert antitumor effects. HCC have been shown to exhibit somatostatin receptors. The present randomized placebo-controlled study aimed at examining the efficacy of long-acting octreotide (Sandostatin LAR) for the treatment of advanced HCC. Seventy patients were randomized to receive a 2-week course of 250 μg short-acting octreotide twice daily followed by Sandostatin LAR 30 mg injection once every 4 weeks for 6 doses (n = 35) or placebo (control group) (n = 35). The clinical and laboratory parameters were monitored. There was no difference in the cumulative survival between the Sandostatin LAR-treated group compared with the control group [median survival 1.93 months vs. 1.97 months, respectively, P = NS (log-rank test)]. There was no tumor regression and no reduction of α-fetoprotein (AFP) levels in patients receiving Sandostatin LAR treatment. There was no improvement of quality of life assessed by Karnofsky performance score. In conclusion, Sandostatin LAR monotherapy did not have survival benefit in our selected group of patients with advanced HCC. Further studies should be performed in patients with less advanced disease and/or different etiology to evaluate its benefit.
Expression and regulation of gap junctions in rat cholangiocytes
Authors: Bode Hans-Peter , Wang LiFu , Cassio Doris , Leite Fatima M. , St-Pierre Marie V. , Hirata Keiji , Okazaki Keisuke , Sears Marvin L. , Meda Paolo , Nathanson Michael H. , Dufour Jean-François
Published: March 2004

Hepatocytes and other digestive epithelia exchange second messengers and coordinate their functions by communicating through gap junctions. However, little is known about intercellular communication in cholangiocytes. The aim of this study was to examine expression and regulation of gap junctions in cholangiocytes. Connexin expression was determined by confocal immunofluorescence in rat bile ducts and in normal rat cholangiocyte (NRC) cells, a polarized cholangiocyte cell line. Intercellular Ca2+ signaling was monitored by fluorescent microscopy. Microinjection studies assessed regulation of gap junction permeability in NRC cells and in SKHep1 cells, a liver-derived cell line engineered to express connexin 43. Immunochemistry showed that cholangiocytes from normal rat liver as well as the NRC cells express connexin 43. Localization of apical, basolateral, and tight junction proteins confirmed that NRC cells are well polarized. Apical exposure to ATP induced Ca2+ oscillations that were coordinated among neighboring NRC cells, and inhibition of gap junction conductance desynchronized the Ca2+ oscillations. NRC cells transfected with a connexin 43 antisense were significantly less coupled. Transcellular dye spreading was inhibited by activation of protein kinase A or protein kinase C. The same was observed in transfected SKHep1 cells, which expressed only connexin 43. Rat cholangiocytes and NRC cells express connexin 43, which permits synchronization of Ca2+ signals among cells. Permeability of connexin 43-gap junctions is negatively regulated by protein kinases A and C. In conclusion, cholangiocytes have the capacity for intercellular communication of second messenger signals via gap junctions in a fashion that is under hormonal control.
Delayed liver regeneration in peroxisome proliferator-activated receptor-α-null mice
Authors: Anderson Steven P. , Yoon Lawrence , Richard Erika B. , Dunn Corrie S. , Cattley Russell C. , Corton Christopher J.
Published: March 2004

Peroxisome proliferator chemicals, acting via the peroxisome proliferator-activated receptor-α (Pparα), are potent hepatic mitogens and carcinogens in mice and rats. To test whether Pparα is required for hepatic growth in response to other stimuli, we studied liver regeneration and hepatic gene expression following partial hepatectomy (PH) of wild-type and Pparα-null mice. Pparα-null mice had a 12- to 24-hour delay in liver regeneration associated with a delayed onset and lower peak magnitude of hepatocellular DNA synthesis. Furthermore, these mice had a 24-hour lag in the hepatic expression of the G1/S checkpoint regulator genes Ccnd1 and cMyc and increased expression of the IL-1β cytokine gene. Hepatic expression of Ccnd1, cMyc, IL-1r1, and IL-6r was induced in wild-type mice, but not Pparα-null mice, after acute exposure to the potent Pparα agonist Wy-14,643, indicating a role for Pparα in regulating the expression of these genes. Expression of the fatty acid ω-hydroxylase gene Cyp4a14, a commonly used indicator gene for Pparα activation, was strongly induced in wild-type mice after hepatectomy, suggesting that altered hepatocyte lipid processing may also contribute to the impaired regeneration in mice lacking the Pparα gene. In conclusion, liver regeneration in Pparα-null mice is transiently impaired and is associated with altered expression of genes involved in cell cycle control, cytokine signaling, and fat metabolism. (Hepatology 2002;36:544-554.)
Cell adhesion regulates platelet-derived growth factor-induced MAP kinase and PI-3 kinase activation in stellate cells
Authors: Carloni Vinicio , DeFranco Raffaella M. S. , Caligiuri Alessandra , Gentilini Alessandra , Sciammetta Silvia Cappadona , Baldi Elisabetta , Lottini Benedetta , Gentilini Paolo , Pinzani Massimo
Published: March 2004

The biologic effects of growth factors are dependent on cell adhesion, and a cross talk occurs between growth factors and adhesion complexes. The aim of the present study was to evaluate the influence of cell adhesion on the major intracellular signaling pathways elicited by platelet-derived growth factor (PDGF) in hepatic stellate cells (HSC). PDGF signaling was investigated in an experimental condition characterized by lack of cell adhesion for different intervals of time. Basal and PDGF-induced focal adhesion kinase (FAK) tyrosine phosphorylation was maintained in a condition of cell suspension for 2, 4, and 6 hours, whereas it was completely lost after 12 and 24 hours. We examined MAP kinase activity at 2 and 24 hours, corresponding to the higher and lower levels of FAK phosphorylation. In these experiments, MAP kinase activity correlated with FAK phosphorylation. Stimulation with PDGF was able to cause Ras-GTP loading only in adherent cells. The ability of PDGF to induce phosphatidylinositol 3-kinase (PI 3-K) activity was abrogated in cells maintained in suspension. The Ser473 phosphorylation of Akt was only marginally affected by the lack of cell adhesion. We then evaluated the association of FAK with c-Src. This association was found to be cell adhesion dependent, and it did not appear to be dependent from phosphorylated FAK. These changes in PDGF-induced intracellular signaling were associated with a remarkable reduction of PDGF-proliferative potential in nonadherent cells, although no marked differences in the apoptotic rate were observed. In conclusion, these results suggest that cell adhesion differentially regulates major signaling pathways activated by PDGF in HSC.
Endoscopic ligation compared with sclerotherapy for bleeding esophageal varices in children with extrahepatic portal venous obstruction
Authors: Zargar Showkat Ali , Javid Gul , Khan Bashir Ahmad , Yattoo Ghulam Nabi , Shah Altaf Hussain , Gulzar Ghulam Mohammad , Singh Jaswinder , Rehman Bilal-ul , Din Ziaud
Published: March 2004

Endoscopic sclerotherapy is an effective treatment for bleeding esophageal varices, but it is associated with significant complications. Endoscopic ligation, a new form of endoscopic treatment for bleeding varices, has been shown to be superior to sclerotherapy in adult patients with cirrhosis. To determine the efficacy and safety of endoscopic sclerotherapy and ligation, the 2 methods were compared in a randomized control trial in 49 children with extrahepatic portal venous obstruction who had proven bleeding from esophageal varices. Twenty-four patients were treated with sclerotherapy and 25 with band ligation. No significant differences were found between the sclerotherapy and ligation groups in arresting active index bleeding (100% each) and achieving variceal eradication (91.7% vs. 96%, P = .61). Band ligation eradicated varices in fewer endoscopic sessions than did sclerotherapy (3.9 ± 1.1 vs. 6.1 ± 1.7, respectively, P < .0001). The rebleeding rate was significantly higher in the sclerotherapy group (25% vs. 4%, P = .049), as was the rate of major complications (25% vs. 4%, P = .049). After eradication, esophageal variceal recurrence was not significantly different in patients treated by ligation than by sclerotherapy (17.4% vs. 10%, P = .67). In conclusion, variceal band ligation in children is a safe and effective technique that achieves variceal eradication more quickly, with a lower rebleeding rate and fewer complications compared with sclerotherapy.
Apoptosis of human hepatic myofibroblasts promotes activation of matrix metalloproteinase-2
Authors: Preaux Anne-Marie , D’Ortho Marie-Pia , Bralet Marie-Pierre , Laperche Yannick , Mavier Philippe
Published: March 2004

Liver fibrosis is potentially reversible after removal of the injurious agent. Fibrosis resolution is characterized by apoptosis of hepatic myofibroblasts and degradation of extracellular matrix components. Matrix metalloproteinase-2 (MMP-2) is involved in matrix remodeling. In the liver, it is synthesized by myofibroblasts, secreted as a proenzyme, and activated by membrane type-MMPs (MT-MMP) such as MT1-MMP. The goal of this work was to determine whether apoptosis induction in human hepatic myofibroblasts modulates the gene expression of MMP-2 and/or its activation by MT1-MMP. Induction of apoptosis by cytochalasin D or C2-ceramide did not modulate MMP-2 mRNA expression. In contrast, apoptosis was associated with marked activation of pro-MMP-2, as shown by gelatin zymography, which revealed the presence of the 59-kd active form, whereas untreated cells only expressed the 66-kd proform. SB-203580, a specific inhibitor of p38 MAPK, selectively abrogated both C2-ceramide-induced apoptosis and pro-MMP-2 activation. Apoptosis-induced pro-MMP-2 activation was inhibited by the tissue inhibitors of metalloproteinases (TIMP)-2 but not by TIMP-1, implying involvement of an MT-MMP-mediated process. Induction of apoptosis by cytochalasin D and C2-ceramide upregulated MT1-MMP protein expression and MT1-MMP mRNA expression. In conclusion, apoptosis of hepatic myofibroblasts induces pro-MMP-2 activation through increased MT1-MMP expression.
Altered expression of E-cadherin in hepatocellular carcinoma: Correlations with genetic alterations, β-catenin expression, and clinical features
Authors: Wei Yu , Van Nhieu Jeanne Tran , Prigent Sylvie , Srivatanakul Petcharin , Tiollais Pierre , Buendia Marie-Annick
Published: March 2004

E-cadherin is a key cell adhesion protein implicated as a tumor/invasion suppressor in human carcinomas and a binding partner of β-catenin, which plays a critical role in Wnt signaling and in tumorigenesis. Here we report genetic and expression studies of E-cadherin and β-catenin in hepatocellular carcinoma (HCC). Immunohistochemical analysis of E-cadherin expression in 37 HCCs and adjacent nontumor tissues revealed important variations among tumor samples, ranging from complete or heterogeneous down-regulation in 35% of cases to marked overexpression in 40% of tumors. Loss of E-cadherin expression was closely associated with loss of heterozygosity (LOH) at the E-cadherin locus and methylation of CpG islands in the promoter region (P < .002), predominantly in hepatitis B virus (HBV)-related tumors (P < .005). No mutation of the E-cadherin gene could be detected in the tumors examined, suggesting the requirement for reversible mechanisms of E-cadherin down-regulation. In most HCCs, including E-cadherin-positive and -negative cases, β-catenin was strongly expressed at the cell membrane and nuclear accumulation of the protein was correlated with the presence of mutations in the β-catenin gene itself, but not with E-cadherin loss. At difference with a number of epithelial cancers, vascular invasion was frequently noted in HCCs showing enforced expression of the membranous E-cadherin/β-catenin complex. In conclusion, these data support the notion that E-cadherin might play diverse and seemingly paradoxic roles in HCC, reflecting specific requirements for tumor growth and spread in the liver environment.
Noninvasive prediction of cirrhosis in C282Y-linked hemochromatosis
Authors: Beaton Melanie , Guyader Dominique , Deugnier Yves , Moirand Romain , Chakrabarti Subrata , Adams Paul
Published: March 2004

The aim of the present study was to examine the predictive accuracy of noninvasive clinical and biochemical variables associated with cirrhosis among patients with C282Y homozygous hemochromatosis. Sixteen clinical and laboratory variables were recorded at the time of diagnosis in 193 Canadian C282Y homozygous patients. All patients underwent percutaneous liver biopsy and 27 (14%) had biopsy specimen-proven cirrhosis. Prediction of cirrhosis was assessed first by univariate regression analysis. Variables significantly related to cirrhosis were then evaluated by stepwise linear multivariate regression. Receiver operating characteristic curve analysis of the most informative variables from multivariate analysis was then used to devise a clinically applicable index for the noninvasive prediction of cirrhosis. This index was then validated in 162 C282Y homozygous patients in France. Ferritin, blood platelets, and aspartate transaminase (AST) level were selected for the clinical index. The combination of ferritin levels of 1,000 μg/L or greater, platelet levels of 200 × 109/L or less, and AST levels above the upper limit of normal led to a correct diagnosis of cirrhosis in 77% of Canadian patients. In the French patients, this led to a correct diagnosis of cirrhosis in 90%. In conclusion, in C282Y homozygous patients, a combination of easily measured laboratory variables (ferritin, platelets, AST) can be used to make the diagnosis of cirrhosis in approximately 81% of cases, reducing the need for liver biopsy.
The dynamics of T-lymphocyte responses during combination therapy for chronic hepatitis C virus infection
Authors: Barnes Eleanor , Harcourt Gillian , Brown Dave , Lucas Michaela , Phillips Rodney , Dusheiko Geoffrey , Klenerman Paul
Published: March 2004

Hepatitis C virus (HCV) readily sets up a persistent infection and is a major cause of liver disease worldwide. Interferon alfa and ribavirin therapy lead to sustained clearance of virus in 31% to 64% of patients with type 1 and non-type 1 genotypes, respectively. It is not clear to what extent these drugs act directly to reduce HCV replication, or indirectly via host immune responses, and what evoked immune responses are associated with clinical outcome. We have examined prospectively 15 patients with chronic HCV infection before, during, and after combination therapy. Quantitative assays for HCV antigen-specific CD4+ and CD8+ T-cell responses, and flow cytometric assays for analysis of the phenotype of T cells, in addition to viral sequencing of core protein, were performed throughout the treatment and follow-up period over 18 months. We found enhancement of proliferative T-cell responses during therapy. Proliferative responses are strikingly heterogeneous in terms of specificity, kinetics, and magnitude. Proliferative responses are often not associated with interferon-γ release. T-cell responses are rarely sustained irrespective of treatment outcome and this is not due to the evolution of new immune escape variants. T-cell responses tend to peak late in the course of treatment. In conclusion, combination therapy for HCV has a transient effect on host virus-specific T cells in the blood. Induction of sustained T-cell responses may require additional immune modulation laterin therapy.