A real-world experience of SARS-CoV-2 infection in a tertiary referral centre of Montréal: Unexpected low prevalence and low mortality

BACKGROUND: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with chronic liver disease (CLD) and liver transplant (LT) recipients remains a concern. The aim of this study was to report the impact of coronavirus disease 2019 (COVID-19) infection among patients at the tertiary health care centre Centre hospitalier de l’Université de Montréal (CHUM) during the first wave of the SARS-CoV-2 pandemic. METHODS: This real-world, retrospective cohort included all patients admitted to our liver unit and/or seen as an outpatient with CLD with or without cirrhosis and/or LT recipients who tested positive to SARS-CoV-2 infection. Cases were considered positive as defined by the detection of SARS-CoV-2 by reverse-transcription polymerase chain reaction (RT-PCR) on nasopharyngeal swabs. RESULTS: Between April 1 and July 31, 2020, 5,637 were admitted to our liver unit and/or seen as outpatient. Among them, 42 were positive for SARS-CoV-2. Twenty-two patients had CLD without cirrhosis while 16 patients had cirrhosis at the time of the infection (13, 2, and 1 with Child–Pugh A, B, and C scores, respectively). Four were LT recipients. Overall, 15 of 42 patients (35.7%) were hospitalized; among them, 7 of 42 (16.7%) required respiratory support and 4 of 42 (9.5%) were transferred to the intensive care unit. Only 4 of 42 (9.5%) patients died: 2 with CLD without cirrhosis and 2 with CLD with cirrhosis. Overall survival was 90.5%. CONCLUSION: This real-world study demonstrates an unexpectedly low prevalence and low mortality in the context of SARS-CoV-2 infection among patients with CLD with or without cirrhosis and LT recipients.

Gastric antral vascular ectasia is more frequent in patients with non-alcoholic steatohepatitis-induced cirrhosis

BACKGROUND

Gastric antral vascular ectasia (GAVE) is an uncommon cause of occult gastrointestinal (GI) bleeding. Based on clinical observations, we hypothesized that GAVE was more common in patients with non-alcoholic steatohepatitis (NASH) cirrhosis.

METHODS

We performed this retrospective study at Centre Hospitalier de l'Université de Montréal (CHUM). We included all cirrhotic patients who had undergone an esophagogastroduodenoscopy (EGD) between 2009 and 2011. GAVE was diagnosed based on a typical endoscopic appearance. NASH cirrhosis was diagnosed in patients with a metabolic syndrome after excluding other causes of liver disease. GAVE was considered symptomatic if it required treatment.

RESULTS

We included 855 cirrhotic patients in the study. The median age was 58 (range 19-88) years. The etiology of cirrhosis was as follows: NASH in 18% (n = 154), autoimmune diseases in 15.1% (n = 129), hepatitis B virus (HBV) in 6.3% (n = 54), hepatitis C virus (HCV) in 19.4% (n = 166), alcohol in 25.7% (n = 220), alcohol plus HCV in 7.8% (n = 67), cryptogenic in 2.8% (n = 24), and other etiologies in 4.8% (n = 41). GAVE was more frequently observed among patients with NASH cirrhosis than in cirrhosis of other etiologies (29.2% vs. 9.4%, respectively; p < 0.001). In multivariate analysis, NASH was strongly associated with GAVE with an odds ratio (OR) of 3.73 (95% CI 2.36 to 5.90, p < 0.001), and the association was stronger with symptomatic GAVE (OR 5.77, 95% CI 2.93 to 11.38).

CONCLUSIONS

NASH cirrhosis is a major risk factor for GAVE and symptomatic GAVE.

Type 3 cytokines IL-17A and IL-22 drive TGF-β-dependent liver fibrosis

Inflammatory immune cells can modulate activation of hepatic stellate cells (HSCs) and progression of liver fibrosis. Type 3 inflammation characterized by production of interleukin-17A (IL-17) and IL-22 by innate and adaptive immune cells is implicated in many inflammatory conditions of the gut and can be counteracted by regulatory T cells (Tregs), but its contribution to liver fibrosis is still poorly understood. Here, we evaluated the contribution of type 3 inflammation in liver fibrosis using clinical liver biopsies, in vitro stimulation of primary HSCs, and in vivo mouse models. We report dysregulated type 3 responses in fibrotic lesions with increased IL-17+CD4+/FOXP3hiCD4+ ratio and increased IL-17 and IL-22 production in advanced liver fibrosis. Neutrophils and mast cells were the main sources of IL-17 in situ in humans. In addition, we demonstrate a new profibrotic function of IL-22 through enhancement of transforming growth factor-β signaling in HSCs in a p38 mitogen-activated protein kinase-dependent manner. In vivo, IL-22RA1 knockout mice exhibited reduced fibrosis in response to thioacetamide and carbon tetrachloride. Blocking either IL-22 or IL-17 production using aryl hydrocarbon receptor or RAR-related orphan receptor gamma-t antagonists resulted in reduced fibrosis. Together, these data have identified a pathogenic role for type 3 immune response mediated by IL-22 in driving liver fibrosis during chronic liver injury.

Th17 Cytokines Drive Liver Fibrosis Progression by Regulating TGF-β Signaling through Activation of MAPKs

Activation of hepatic stellate cells (HSCs) is a key event in the initiation of liver fibrosis. We and others have demonstrated that IL-17A produced by Th17 cells promotes activation of HSCs. Th17 cells also produce IL-22, an enigmatic cytokine with pro-inflammatory and hepatoprotective properties. In addition, regulatory T cells (Treg) negatively modulate activation of HSCs. We hypothesized that liver fibrosis progression results from an alteration in the Th17/Treg ratio leading to an imbalance in pro-fibrotic Th17 cytokines in the liver. We examined ex vivo the frequency of Th17 and Treg populations and the cytokine profile of intrahepatic lymphocytes in liver biopsy samples (n=32). We observed increased Th17/Treg ratio in advanced as compared to moderate or no-fibrosis. Furthermore, we observed a bias towards Th17 cytokines in fibrotic livers with viral-hepatitis both in situ and ex vivo. All biopsies exhibited a 5-fold increase in IL-22 in fibrotic livers irrespective of aetiology. In vitro stimulation of HSCs with IL-22 sensitized them to suboptimal doses of TGF-β and activated p38 pathways. Chemical inhibition of p38 suppressed the pro-fibrogenic effect of IL-22. In vivo, lack of IL-22 signaling protected mice against liver fibrosis. IL-22RA1 Knockout mice exhibited reduced collagen deposition and expression of pro-fibrotic genes (ACTA2, LOXL2, TIMP-I, TGFb1, COL1A1) in comparison to wild-type littermates. Our results suggest a dysregulated Th17 response with increased IL-22 signaling in advanced fibrosis from all different aetiologies. Finally, we have identified IL-22 as a common factor in advanced liver fibrosis acting through sensitization of HSCs to TGF-β in a p38-dependent manner.

Novel E2 Glycoprotein Tetramer Detects Hepatitis C Virus-Specific Memory B Cells

Acute hepatitis C virus (HCV) infection culminates in viral persistence in the majority of cases. Abs that recognize the envelope glycoproteins E1 and E2 are generated during the late stages of acute infection, yet their contribution to spontaneous viral clearance remains controversial. Investigation of the humoral responses during acute HCV infection have been limited by the inability to directly identify and characterize HCV-specific B cells. In this study we describe the development of a novel tetramer of the E2 glycoprotein ectodomain (J6, genotype 2a strain), which allowed us to visualize E2-specific B cells longitudinally in the peripheral blood of HCV-infected individuals. HCV-specific class-switched memory B cells were detected in 3 out of 7 participants during late acute infection, with a mean frequency of 0.63% for positive samples (range 0.16-0.67%) and in 7 out of 7 participants with chronic infection with a mean frequency of 0.47% (range 0.20-0.78%). In a cross-sectional study, E2 tetramer positive population was detected in 28 out of 31 chronically infected individuals. Deep sequencing of the BCR from E2-specific class-switched memory B cells sorted from two independent participants revealed a focused repertoire suggestive of clonal selection. Tetramer-specific B cells exhibited skewed CDR3 length distribution and increased mutation frequency compared with naive B cells. This BCR profile is indicative of clonal expansion and affinity maturation. E2 tetramer allows for specific and sensitive ex vivo characterization of rare HCV-specific B cells in infected individuals, and will enable researchers to gain a better understanding of humoral immunity in HCV infection.

Transarterial embolization therapies for the treatment of hepatocellular carcinoma: CEPO review and clinical recommendations

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most deadly cancers in the world and its incidence rate has consistently increased over the past 15 years in Canada. Although transarterial embolization therapies are palliative options commonly used for the treatment of HCC, their efficacy is still controversial. The objective of this guideline is to review the efficacy and safety of transarterial embolization therapies for the treatment of HCC and to develop evidence-based recommendations.

METHOD

A review of the scientific literature published up to October 2013 was performed. A total of 38 studies were included.

RECOMMENDATIONS

Considering the evidence available to date, the CEPO recommends the following: (i) transarterial chemoembolization therapy (TACE) be considered a standard of practice for the palliative treatment of HCC in eligible patients; (ii) drug-eluting beads (DEB)-TACE be considered an alternative and equivalent treatment to conventional TACE in terms of oncological efficacy (overall survival) and incidence of severe toxicities; (iii) the decision to treat with TACE or DEB-TACE be discussed in tumour boards; (iv) bland embolization (TAE) not be considered for the treatment of HCC; (v) radioembolization (TARE) not be considered outside of a clinical trial setting; and (vi) sorafenib combined with TACE not be considered outside of a clinical trial setting.

Organochlorine pesticides in green mussel, Perna viridis, from the Cienfuegos Bay, Cuba

The green mussel, Perna viridis, was used to measure bioaccumulated levels of organochlorine pesticides in the marine environment of Cuba. Samples were collected in the Cienfuegos Bay between January and December 2010. The organochlorine pesticides (i.e. DDT, Dieldrin, Chlordane, Endosulfan, HCB, Aldrin, Heptachlor and Lindane) were quantified by gas chromatography. The sum of all organochlorine pesticides in P. viridis was 6.31 ng g(-1). The concentration ranged from 3.53 to 4.42 ng g(-1) dry weight (dw) for DDTs (i.e. sum of pp' DDT, pp' DDD, op' DDE and pp' DDE); 1.7-1.9 ng g(-1) dw for Dieldrin; 0.17-0.20 ng g(-1) dw for Chlordanes; 0.14-0.16 ng g(-1) dw for Endosulfan; 0.11-0.17 ng g(-1) dw for HCB; 0.07-0.11 ng g(-1) dw for Aldrin; 0.046-0.054 ng g(-1) dw for Heptachlor and 0.035-0.039 ng g(-1) dw for Lindane. These levels can be considered as low when compared to reported values from similar studies conducted elsewhere in the world. The concentrations of all organochlorines residues detected in this study fell below the EU Maximum Residue Limits.

Management and treatment of hepatitis B virus in patients with HIV infection: A practical guide for health care professionals

The management and treatment of HIV and hepatitis B virus (HBV)-coinfected patients present specific challenges for clinicians. The morbidity and mortality related to these concomitant infections are growing concerns, while the use of antiviral drugs effective against both viruses complicates therapeutic decision making. The present document provides guidelines for physicians regarding care and treatment of patients coinfected with HIV and HBV. Primary prevention of HBV in HIV-positive patients is achieved through appropriate vaccination schedules. Follow-up before treatment of HBV may include liver biopsy, screening for hepatocellular carcinoma and testing for esophageal varicies in cases of cirrhosis. In HBV-infected patients requiring treatment, recommendations regarding initiation, duration and choice of first-line drugs are made. Finally, in the case of resistance, appropriate alternative therapies are necessary.

Distribution of petroleum hydrocarbons and organochlorinated contaminants in marine biota and coastal sediments from the ROPME Sea Area during 2005

The composition and spatial distribution of various petroleum hydrocarbons (PHs), comprising both aliphatic and polycyclic aromatic hydrocarbons (PAHs), and selected chlorinated pesticides and PCBs were measured in biota and coastal sediments from seven countries in the Persian Gulf and the Gulf of Oman (Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates). Evidence of extensive marine contamination with respect to organochlorinated compounds and PHs was not observed. Only one site, namely the BAPCO oil refinery in Bahrain, was considered to be chronically contaminated. Comparison of the results from this survey for Σ DDTs and Σ PCBs in rock oysters from the Gulf of Oman with similar measurements made at the same locations over the past two decades indicates a temporal trend of overall decreasing Σ PCB concentrations in oysters, whereas Σ DDTs levels have little changed during that period.

PCBs in sediments and oysters of Manila Bay, the Philippines

Polychlorinated biphenyls (PCBs) were analyzed in sediment and oyster samples from coastal sites inside Manila Bay. Concentrations for 13 individual PCB congeners and total PCBs are reported herein. Median SigmaPCB concentration in sediments was 0.46 ng g(-1) dry weight (range 0.10-1.5 ng g(-1)) and in oysters it was 15 ng g(-1) dry weight (range 7-73 ng g(-1)). The most contaminated areas of the bay were the coastal zones of Metropolitan Manila and Bulacan province. A significant correlation (p < 0.01) was found between SigmaPCB concentrations in oysters and in sediments. PCB concentrations measured in the bay sediments were below acute toxic levels to marine biota. Nevertheless, consumption of oysters by human population living around the bay might originate SigmaPCB intake rates estimated at about 2.5 times lower than the tolerance limit. Further environmental surveillance is recommended in order to prevent public health risks that may be posed by these chemicals.

Organic contaminants in the marine environment of Manila Bay, Philippines

Organochlorine pesticides (OCs) and polychlorobiphenyls (PCBs) were determined in sediments and oysters' soft tissues (Cassostrea gigas) collected in selected sites of Manila Bay. Overall, the concentration levels were very low. In sediments, PCBs were the compounds present in higher concentrations, with Sigma13PCB congeners averaging 0.69 +/- 0.46 ng/g (dry weight), followed by SigmaDDT averaging 0.53 +/- 0.28 ng/g and Sigmachlordane with 0.26 +/- 0.28 ng/g. Concentrations measured in oysters averaged 20 +/- 17 ng/g (dry weight) for Sigma13PCB and were higher than SigmaDDT, with 9.5 +/- 2.4 ng/g, and Sigmachlordane, with 3.8 +/- 3.1 ng/g. No dissolved residues of polar compounds, such as herbicides, and organophosphorous and organochlorine pesticides were found in the bay water. In general, results showed that concentrations of organochlorine pesticide residues, such as DDT, hexachlorocyclohexane, chlordane, lindane, endosulfan, and heptachlor in sediments and oysters were low in comparison with other coastal areas in Asia, although PCB concentrations in oysters were relatively high in some zones of Manila Bay and indicative of loose control of industrial chemical waste discharges into the bay. Nevertheless, current concentrations of persistent organochlorine contaminants in sediments were under threshold effect levels (TELs) and chronic toxic effects are, thus, unlikely to generate impairment of marine biota in Manila Bay.

Ecological risk assessment of PCBs and other organic contaminant residues in Laguna de Terminos, Mexico

Laguna de Terminos, a wide coastal lagoon system in Campeche, Mexico, was investigated for the contamination by polychlorobiphenyls (PCBs). Distribution of these industrial chemical contaminants along with pesticide residues in the lagoon, as well as their sediment-water partitioning and bioaccumulation by oysters and fish were assessed. Contaminant concentrations in the lagoon were compared with toxicity data for aquatic organisms and the ecotoxicological risks discussed. Current contaminant concentrations generally were several orders of magnitude below acute toxic levels for the most sensitive aquatic species and this seems compatible with the status of nature reserve and functions aimed at Laguna de Terminos. In particular, Penaeidae shrimp species that are the most valuable fisheries resources of Campeche with important populations in the Laguna are not impaired with the current low levels of these contaminants. Nevertheless, due to known environmental persistence, the surveillance of chlorinated contaminant levels in the lagoon ecosystems is recommended.

Pesticide and PCB residues in the aquatic ecosystems of Laguna de Terminos, a protected area of the coast of Campeche, Mexico

The coastal lagoon system of Laguna de Terminos, Campeche, Mexico, a natural reserve since 1994, was investigated for contamination by agricultural and industrial chemical residues. Water, sediment and biota samples were analyzed for a wide variety of organochlorine and organophosphorus compounds. Chlorpyrifos was detected in water in concentrations up to 72 pgL(-1) and, amongst organochlorine compounds, summation operator PCB were measured averaging 1177 pgL(-1) and summation operator DDT 279 pgL(-1). Residues of chlorinated compounds were present in sediments and in biota with summation operator DDT averaging 190 pg g(-1) and 5876 pg g(-1) in sediment and oysters, respectively. Results show that the more widespread contaminants in the Laguna were residues of chlorinated hydrocarbons, such as DDTs, PCBs, endosulfan, and lindane. Concentrations of residues were not at an alarming level and were even lower than reported for other costal lagoons of the region. Still there is a need to implement control measures on persistent and bioaccumulative compounds that may reach the aquatic system of Laguna de Terminos.

Hepatitis B virus genotype G epidemiology and co-infection with genotype A in Canada

Hepatitis B virus (HBV) genotype G (HBV/G) is an unusual variant, and little is known about its epidemiology and natural history, particularly the requirement for a co-infecting HBV genotype and their relationship during infection. This study investigated the quasispecies nature of co-infecting genotypes in 39 samples collected over a 6 year period from 13 HBV/G-infected patients. HBV/G infections were found to occur predominantly in males (92 %) and were primarily associated with male homosexual sex (67 %). All patients were infected with HBV/G and HBV/A, or a recombinant HBV/A/G strain. Co-infecting genotypic prevalence was often observed to fluctuate over time, with periods of HBV/G monoinfection in some patients. The average sequence divergence among Canadian HBV/G strains was 1.57+/-0.62 %. Thus, all HBV/G infections in Canada occur in the context of co-infection or recombination with HBV/A, and strains display increased sequence divergence compared with all known HBV/G sequences described to date.

Early interferon therapy for hepatitis C virus infection rescues polyfunctional, long-lived CD8+ memory T cells

The majority of acute hepatitis C virus (HCV) infections progress to chronicity and progressive liver damage. Alpha interferon (IFN-alpha) antiviral therapy achieves the highest rate of success when IFN-alpha is administered early during the acute phase, but the underlying mechanisms are unknown. We used a panel of major histocompatibility complex class I tetramers to monitor the phenotypic and functional signatures of HCV-specific T cells during acute HCV infection with different infection outcomes and during early IFN therapy. We demonstrate that spontaneous resolution correlates with the early development of polyfunctional (IFN-gamma- and IL-2-producing and CD107a(+)) virus-specific CD8(+) T cells. These polyfunctional T cells are distinguished by the expression of CD127 and Bcl-2 and represent a transitional memory T-cell subset that exhibits the phenotypic and functional signatures of both central and effector memory T cells. In contrast, HCV-specific CD8(+) T cells in acute infections evolving to chronicity expressed low levels of CD127 and Bcl-2, exhibited diminished proliferation and cytokine production, and eventually disappeared from the periphery. Early therapeutic intervention with pegylated IFN-alpha rescued polyfunctional memory T cells expressing high levels of CD127 and Bcl-2. These cells were detectable for up to 1 year following discontinuation of therapy. Our results suggest that the polyfunctionality of HCV-specific T cells can be predictive of the outcome of acute HCV infection and that early therapeutic intervention can reconstitute the pool of long-lived polyfunctional memory T cells.

Agrochemical and polychlorobyphenyl (PCB) residues in the Mekong River delta, Vietnam

An environmental survey on pesticide residues and polychlorobyphenyl compounds (PCBs), encompassing more than 70 polar and non-polar compounds quantifiable by the techniques used, was performed in the Mekong River delta based on analyses of water, sediment and bivalve mollusc samples. Few polar compounds, such as diazinon and fenotrothion, were detected in water but a high number of non-polar chlorinated compounds, such as DDT, HCH, endosulfan and PCBs, were detected in sediments and biota. The highest concentrations measured were of DDT with an average 6.3 ng g(-1) dry weight (range 0.32-67 ng g(-1)) in sediments and 38.6 ng g(-1) (range 5.5-123 ng g(-1)) in molluscs' soft tissues. Amongst chlorinated compounds, DDT concentrations were followed in decreasing order by those of PCB, endosulfan, hexachlorocyclohexane and chlordane. Residues of organochlorine compounds originate from local usage of agrochemicals although with a likely contribution also of atmospheric deposition of residues (not measured) originated elsewhere. Concentrations of PCB and pesticide residues in the aquatic environment of the Mekong River delta are lower than values reported for other regions of Vietnam and Asia. Nevertheless, current concerns about the effects of chlorinated compounds on public health advise improved control of chemical residue discharges in order to abate environmental contamination.

Lamivudine treatment in patients with chronic hepatitis B and cirrhosis

Chronic hepatitis B is a common disease and approximately 20% of infected patients with compensated cirrhosis will decompensate over 5 years. If untreated, the survival of decompensated cirrhosis is poor (15% at 5 years). The extent of hepatitis B virus (HBV) replication, as assessed by serum HBV-DNA level, is a strong predictor of the risk of disease progression and hepatocellular carcinoma. This provides a rationale for antiviral therapy to arrest progression of liver disease. Lamivudine is a pyrimidine analogue that inhibits HBV-DNA reverse transcriptase. It decreases HBV replication, normalises alanine aminotransferase levels and reduces hepatic inflammation and fibrosis in patients with chronic hepatitis B. This article will focus on the use of lamivudine in patients with HBV-cirrhosis. In patients with compensated HBV-cirrhosis, a randomised, placebo-controlled trial has shown that lamivudine significantly reduced the rate of disease progression and hepatocellular carcinoma development over a 3-year period. In patients with decompensated cirrhosis, treatment with lamivudine can produce spectacular improvements of liver function, but the improvement is slow and a clinical benefit is usually not observed until after at least 3-6 months of treatment. A major drawback of lamivudine treatment is the development of resistance, observed in 15-20% of patients after 1 year and up to 70% after 5 years of continued treatment. Thus, patients with HBV-cirrhosis treated with lamivudine should have regular monitoring of serum HBV-DNA levels and prompt institution of additional antiviral therapy if viral breakthrough is observed. Adefovir, tenofovir and entecavir have demonstrated efficacy in patients with lamivudine resistance. In patients with decompensated cirrhosis, in whom the development of resistance can be fatal, combination therapy (such as lamivudine plus adefovir) may prove more effective than monotherapy and this issue needs further study.

Adefovir dipivoxil for wait-listed and post-liver transplantation patients with lamivudine-resistant hepatitis B: final long-term results

Wait-listed (n = 226) or post-liver transplantation (n = 241) chronic hepatitis B (CHB) patients with lamivudine-resistant hepatitis B virus (HBV) were treated with adefovir dipivoxil for a median of 39 and 99 weeks, respectively. Among wait-listed patients, serum HBV DNA levels became undetectable (<1,000 copies/mL) in 59% and 65% at weeks 48 and 96, respectively. After 48 weeks, alanine aminotransferase (ALT), albumin, bilirubin, and prothrombin time normalized in 77%, 76%, 60%, and 84% of wait-listed patients, respectively. Among posttransplantation patients, serum HBV DNA levels became undetectable in 40% and 65% at weeks 48 and 96, respectively. After 48 weeks, ALT, albumin, bilirubin, and prothrombin time normalized in 51%, 81%, 76%, and 56% of posttransplantation patients, respectively. Among wait-listed patients who underwent on-study liver transplantation, protection from graft reinfection over a median of 35 weeks was similar among patients who did (n = 34) or did not (n = 23) receive hepatitis B immunoglobulin (HBIg). Hepatitis B surface antigen was detected on the first measurement only in 6% and 9% of patients who did or did not receive HBIg, respectively. Serum HBV DNA was detected on consecutive visits in 6% and 0% of patients who did or did not receive HBIg, respectively. Treatment-related adverse events led to discontinuation of adefovir dipivoxil in 4% of patients. Cumulative probabilities of resistance were 0%, 2%, and 2% at weeks 48, 96, and 144, respectively. In conclusion, adefovir dipivoxil is effective and safe in wait-listed or posttransplantation CHB patients with lamivudine-resistant HBV and prevents graft reinfection with or without HBIg.

Stepwise process for the development of entecavir resistance in a chronic hepatitis B virus infected patient

BACKGROUND/AIMS

Complex mutants may be selected under sequential anti-VHB pressures. We analyzed the genotypic and phenotypic evolution of the viral quasi-species of a patient who developed resistance to entecavir following lamivudine breakthrough.

METHODS

The polymerase gene was amplified, cloned and sequenced at different time points. Hepatoma cell lines were transfected to compare the replication capacity of HBV mutants and their drug susceptibility.

RESULTS

A mixture of lamivudine-resistant HBV strains coexisted following viral breakthrough to lamivudine, all harboring the rtM204V mutation. The rtV173L+L180M+M204V dominant mutant displayed strong lamivudine-resistance and the highest replication capacity. Following the switch to entecavir, the viral load dropped but the lamivudine-resistant strains continued to be selected. Three years later, the viral load rose again, and a complex mixture of entecavir-resistant strains, all harboring the lamivudine-resistance signature rtL180M+M204V and the rtS202G mutation were observed. Although the rtL180M+S202G+M204V variant, that prevailed at the end of entecavir therapy, did not show the highest viral genome replication capacity, it conferred one of the strongest resistance levels to entecavir.

CONCLUSIONS

We report the selection of complex HBV mutants that escaped lamivudine and entecavir antiviral pressures. Genotypic and phenotypic analysis provided additional information to understand the process of HBV variant selection.

Selection of a multiple drug-resistant hepatitis B virus strain in a liver-transplanted patient

BACKGROUND & AIMS

Sequential anti-hepatitis B virus (HBV) therapy may lead to the selection of complex mutants. We analyzed the genetic and phenotypic evolution of the viral quasispecies of a patient who received successively lamivudine, add-on adefovir+lamivudine, followed by lamivudine+adefovir+hepatitis B immunoglobulins (HBIg) after orthotopic liver transplantation.

METHODS

For genotypic analysis, a 1310-bp region of the polymerase gene was amplified, cloned, and sequenced. Huh-7 cells were transfected to compare the replication fitness of HBV mutants and their susceptibility to drugs.

RESULTS

At baseline, all HBV genomes carried a wild-type (wt) RT gene but 22% harbored the sP120S and 55% the sC107stop mutations within the surface (S) gene associated with vaccine escape. Following viral breakthrough to lamivudine monotherapy, a complex mixture of lamivudine-resistant HBV strains prevailed. Interestingly, among these mutants emerged a population harboring only the rtL180M+A181V mutations, conferring lamivudine-resistance in vitro. After addition of adefovir to the ongoing treatment, viral load dropped, and the patient underwent an orthotopic liver transplantation and received HBIg. As viral load rose again, a single viral population was progressively selected, harboring the rtV173L+L180M+A181V+N236T and sP120S mutations. In vitro, this last mutant showed a level of replication reduced by only 30% compared to wt HBV and a strong resistance to both lamivudine (>1000-fold) and adefovir (>10-fold). It remained sensitive to tenofovir both in vitro and in vivo.

CONCLUSIONS

We report the selection of a complex HBV mutant that escaped the antiviral pressure of lamivudine, adefovir, and HBIg, and provide insight on the process of selection via genotypic and phenotypic analysis.

Coplanar and non-coplanar congener-specificity of PCB bioaccumulation and immunotoxicity in sea stars

The sea star Asterias rubens (L.), a representative species of the North Sea benthic environment, was exposed to a mixture of 10 selected PCB congeners (3 coplanar or c-PCBs, and 7 non-coplanar) via experimentally contaminated sediments. Both the degree of bioaccumulation and subsequent immunotoxic effects of these PCBs were determined. A strong congener-specificity for both bioaccumulation and immunotoxicity was found as well as a probable induction of a congener-specific detoxification mechanism resulting in the dramatic decrease in body levels of the three coplanar congeners tested (PCBs 77, 126 and 169). Moreover, a correlation was found between the bioaccumulation of c-PCBs and their immunotoxic effects. These findings suggest that coplanar congeners should be included in the list of congeners recommended to be analyzed for biological impact-oriented marine monitoring programmes.

Detection of rtN236T and rtA181V/T mutations associated with resistance to adefovir dipivoxil in samples from patients with chronic hepatitis B virus infection by the INNO-LiPA HBV DR line probe assay (version 2)

The nucleotide analog adefovir dipivoxil (ADV) is an effective antiviral treatment for chronic hepatitis B virus (HBV) infection, with resistance to ADV estimated to occur less frequently than resistance to lamivudine treatment. The detection of ADV resistance mutations is necessary during therapy to monitor and anticipate possible treatment failure. The INNO-LiPA HBV DR v2 (LiPA; Innogenetics, Ghent, Belgium) is a DNA hybridization line probe assay for the detection of HBV polymerase mutations associated with resistance to lamivudine and ADV. Evaluation of this assay to detect ADV resistance mutations was performed by analyzing 38 patients treated with ADV. Serial samples taken at 6-month intervals during treatment were available for most patients. A total of 124 samples were analyzed by both LiPA and sequencing. By LiPA analysis, 12 patients (31.5%) were found to have mutations associated with resistance to ADV (rtA181V/T and/or rtN236T). This contrasted with sequence analysis, which found nine patients (24%) with either or both mutations. Twice as many samples were rtN236T positive by LiPA (18 of 124) compared to sequence analysis (9 of 124). LiPA detected the rtN236T mutation at least 6 months earlier than its detection by sequencing in patients for whom consecutive serum samples were available. Although less sensitive, sequencing has the advantage of providing information on other polymerase mutations not represented on LiPA strips. The INNO-LiPA HBV DR v2 assay is a very sensitive and specific assay for the detection of the rtN236T mutation associated with resistance to ADV.

The natural history of chronic hepatitis B virus infection

Under most circumstances, HBV is not cytopathic and it is the immune response of the host that determines the outcome of infection. The most complete immune response is associated with the most severe liver injury and the greatest likelihood of viral clearance, whereas an immature immune response leads to chronic hepatitis. The natural history of chronic hepatitis B is similar to that of acute HBV infection except for the different time frame, and can be viewed in four stages. The first stage is characterized by high viral loads and immune tolerance. In acute infection, this corresponds to the incubation period, but with neonatal chronic infection, this period often lasts for decades. In the second stage, an immunologic response develops leading to hepatocyte necrosis. In patients with chronic infection, stage 2 may persist for 10-20 years and lead to cirrhosis and its complications. When the immune response decreases the number of infected cells, a third stage begins with low viral replication, referred to as the inactive carrier state. In this stage, HBeAg is no longer detectable, a marked decrease in HBV viral load is observed, and aminotransferase levels become normal. During stage 3, some patients continue to have high levels of serum HBV DNA and amino-transferases (referred to as HBeAg-negative chronic hepatitis), because of HBV variants that prevent the production of HBeAg. In the fourth stage, patients become negative for HBeAg and positive for anti-HBs, and HBV DNA is usually no longer detectable in serum, although still present in liver tissue. Immune clearance occurs at a rate of about 1% per year in chronic carriers of HBV During stage 4, some patients can reactivate their hepatitis B when given chemotherapy or immuno-suppressive treatment. Patients with active HBV replication are at increased risk for cirrhosis, hepatic decompensation and hepatocellular carcinoma compared to inactive carriers. Available evidence indicates that control of HBV replication with antiviral agents decreases the incidence of these complications.

Aliphatic and aromatic hydrocarbons in marine biota and coastal sediments from the Gulf and the Gulf of Oman

The composition and spatial distribution of aliphatic and polycyclic aromatic hydrocarbons (PAHs) were investigated in biota and coastal sediments from four countries surrounding the Gulf (Bahrain, Qatar, United Arab Emirates and Oman). The levels of total petroleum hydrocarbons (TPH), aliphatic unresolved mixture and PAHs in sediments and biota were relatively low compared to world-wide locations reported to be chronically contaminated by oil. Only in the case of the sediments collected near the BAPCO oil refinery in Bahrain, having concentrations of 779 microg g(-1) total petroleum hydrocarbon equivalents and 6.6 microg g(-1) Sigma PAHs, can they be categorized as chronically contaminated. Some evidence of oil contamination was also apparent in sediments and bivalves around Akkah Head and Abu Dhabi in the UAE, and near Mirbat in Oman. Contaminant patterns in sediments and biota indicated that the PAHs were mainly from fossil sources, with the exception of the high PAH concentrations in sediments near the BAPCO refinery that contained substantial concentrations of carcinogenic PAH combustion products.

Chlorinated hydrocarbons in marine biota and coastal sediments from the Gulf and Gulf of Oman

The spatial distribution of various organochlorinated compounds was investigated in the Gulf and Gulf of Oman based on marine biota (fish and various bivalves) and coastal sediment collected in Bahrain, Oman, Qatar and the United Arab Emirates (UAE) during 2000-2001. Several potential organic contaminants from agricultural (e.g., DDT and its breakdown products, lindane, endrin, dieldrin, endosulfan) and industrial (PCBs) sources were measured. Sediment burdens for all compounds, even for an apparent hot spot near a refinery in Bahrain, were amongst the lowest reported for surface sediments from other seas. Concentrations of DDTs were low in the muscle and liver of all fish (orange spotted grouper and the spangled emperor) analysed. Similarly, the levels of chlorinated hydrocarbons were low in the various bivalve species, notably rock oysters and pearl oysters. These results contribute to the sparse regional database for organochlorinated compounds in the marine environment. Moreover, they can be used as the most recent end point for elucidating temporal trends. Whereas the levels, albeit relatively low, SigmaDDTs in the rock oysters from the Gulf of Oman have remained uniform, there has been an irregular but generally decreasing trend in concentrations of summation SigmaPCBs during the last two decades.

Susceptibility to antivirals of a human HBV strain with mutations conferring resistance to both lamivudine and adefovir

Mutations within the hepatitis B virus (HBV) polymerase gene conferring drug-resistance are selected during prolonged lamivudine (3TC) or adefovir dipivoxil (ADV) treatment. Because there is no other approved drug against HBV, treatments with 3TC or ADV are used either sequentially or in addition, depending on treatment response or failure. Considering the use of de novo or add-on 3TC+ADV bitherapy, we investigated the possibility of the emergence of an HBV strain harboring polymerase mutations conferring resistance to both 3TC (rtL180M+M204V) and ADV (rtN236T). We constructed the L180M+M204V+N236T mutant and determined its replication capacity and its susceptibility to different nucleos(t)ide analogs in transiently transfected hepatoma cell lines. The triple mutant replicates its genome in vitro, but less efficiently than either the wild-type (wt) HBV or L180M+M204V and N236T mutants. Phenotypic assays indicated that the L180M+M204V+N236T mutant is resistant to pyrimidine analogs (3TC, -FTC, beta-L-FD4C, L-FMAU). Compared with wt HBV, this mutant displays a 6-fold decreased susceptibility to ADV and entecavir and a 4-fold decreased susceptibility to tenofovir. Interferon alfa inhibited equally the replication of wt and L180M+M204V+N236T HBV. In conclusion, the combination of rtL180M+M204V and rtN236T mutations impairs HBV replication and confers resistance to both 3TC and ADV in vitro. These results suggest that the emergence of the triple mutant may be delayed and associated with viral resistance in patients treated with 3TC+ADV. However, other nucleos(t)ide analogs in development showed an antiviral activity against this multiresistant strain in vitro. This provides a rationale for the clinical evaluation of de novo combination therapies.

The management of chronic viral hepatitis: a Canadian consensus conference 2004

Several government and nongovernment organizations held a consensus conference on the management of acute and chronic viral hepatitis to update previous management recommendations. The conference became necessary because of the introduction of new forms of therapy for both hepatitis B and hepatitis C. The conference issued recommendations on the investigation and management of chronic hepatitis B, including the use of lamivudine, adefovir and interferon. The treatment of hepatitis B in several special situations was also discussed. There were also recommendations on the investigation and treatment of chronic hepatitis C and hepatitis C-HIV coinfection. In addition, the document makes some recommendations about the provision of services by provincial governments to facilitate the delivery of care to patients with hepatitis virus infection. The present document is meant to be used by practitioners and other health care providers, including public health staff and others not directly involved in patient care.

The management of chronic viral hepatitis: A Canadian consensus conference 2004

Several government and nongovernment organizations held a consensus conference on the management of acute and chronic viral hepatitis to update previous management recommendations. The conference became necessary because of the introduction of new forms of therapy for both hepatitis B and hepatitis C. The conference issued recommendations on the investigation and management of chronic hepatitis B, including the use of lamivudine, adefovir and interferon. The treatment of hepatitis B in several special situations was also discussed. There were also recommendations on the investigation and treatment of chronic hepatitis C and hepatitis C-HIV coinfection. In addition, the document makes some recommendations about the provision of services by provincial governments to facilitate the delivery of care to patients with hepatitis virus infection. The present document is meant to be used by practitioners and other health care providers, including public health staff and others not directly involved in patient care.

Organochlorinated compounds in Caspian Sea sediments

Several organochlorinated contaminants, including numerous pesticides, were determined in coastal sediments from the Caspian Sea. The most important contaminants were p,p'-DDT (up to 7400 pg g(-1)) and its breakdown products, p,p'-DDD (up to 3400 pg g(-1)) and p,p'-DDE (up to 1300 pg g(-1)). Although the contamination was most severe in Azerbaijan, the sediment concentrations and percentage distribution of the three DDT-related compounds indicated that such contamination constitutes a contemporary and ubiquitous problem in the Caspian Sea. Lindane represented the second most significant contaminant, particularly in the Russian Federation, with concentrations up to 609 pg g(-1). The concentrations of HCB and other chlorinated pesticides (cis- and trans-chlordane, methoxychlor, heptachlor, heptachlor epoxide, aldrin, endrin, and endosulfans) were lower and not generally of concern, but the pesticides did demonstrate markedly different distributions reflecting differing agricultural usage in the region. The concentrations of Sigma PCBs were also quite low and ranged from 0.03 to 6.4 ng g(-1), with the highest amounts in the Russian Federation and Azerbaijan.

Adefovir dipivoxil therapy for lamivudine-resistant hepatitis B in pre- and post-liver transplantation patients

Three-hundred and twenty-four patients were enrolled in an open-label, multicenter, international study in which pre- and post-liver transplantation (LT) patients with recurrent chronic hepatitis B (CHB) and evidence of lamivudine-resistant HBV were treated with adefovir dipivoxil 10 mg once daily. In the pre- and post-LT cohorts, 128 and 196 patients were treated for a median duration of 18.7 and 56.1 weeks, respectively. In patients who received 48 weeks of treatment, 81% of the pre-LT and 34% of the post-LT cohort achieved undetectable serum hepatitis B virus (HBV) DNA (Roche Amplicor Monitor polymerase chain reaction [PCR] assay lower limit of quantification [LLQ] < 400 copies/mL) with a median change in serum HBV DNA from baseline of -4.1 log(10) and -4.3 log(10) copies/mL, respectively. Serum alanine aminotransferase (ALT), albumin, bilirubin, and prothrombin time normalized in 76%, 81%, 50%, and 83% of pre-LT patients and 49%, 76%, 75%, and 20% of post-LT patients. The Child-Pugh-Turcotte (CPT) score improved in over 90% of patients in both cohorts. Genotypic analysis of 122 HBV baseline samples revealed that 98% of these patients had lamivudine-resistant mutant HBV. No adefovir resistance mutations were identified in patients after 48 weeks of therapy. One-year survival was 84% for pre-LT and 93% for post-LT patients (Kaplan-Meier analysis). Treatment-related adverse effects associated with adefovir dipivoxil in this setting were primarily mild to moderate in severity. In conclusion, 48 weeks of adefovir dipivoxil resulted in significant improvements in virologic, biochemical, and clinical parameters in CHB patients pre- and post-LT with lamivudine-resistant HBV.

Selection of a hepatitis B virus strain resistant to adefovir in a liver transplantation patient

BACKGROUND/AIMS

In contrast to lamivudine, adefovir dipivoxil (ADV) therapy is associated with delayed and infrequent selection of drug resistant hepatitis B virus (HBV).

METHODS

A 52 year-old man was treated with lamivudine for an HBV recurrence on his liver graft. A viral breakthrough was observed and the patient received ADV. Serum HBV DNA decreased rapidly and lamivudine was discontinued while ADV monotherapy was maintained. Serum HBV DNA levels remained suppressed until a second breakthrough was observed. Lamivudine was then reintroduced together with ADV, and serum HBV DNA became undetectable by polymerase chain reaction.

RESULTS

Sequence analyses of the HBV polymerase gene revealed a sequential selection of lamivudine resistance mutations L180M+M204V, followed by a reversion to wild-type, and subsequently the selection of a novel adefovir resistance mutation N236T. Phenotypic analyses in cell culture assays demonstrated that the HBV isolates at the time of ADV breakthrough had reduced susceptibility to ADV. This mutant remained sensitive to lamivudine, entecavir and emtricitabine in vitro.

CONCLUSIONS

We describe the first case of sequential selection of lamivudine and adefovir resistant strains of HBV in a liver transplantation patient. The selection of the N236T polymerase mutant was associated with resistance to ADV but remained sensitive to lamivudine in vitro and in vivo.

Toxaphene residues from cotton fields in soils and in the coastal environment of Nicaragua

Toxaphene (camphechlor) was intensively used in the cotton growing fields of Nicaragua for decades with application rates as high as 31 kg ha(-1) in 1985. Although the use of this compound has recently been discontinued in the country, its intensive use in the past and its long persistence in soil allowed for the build up of large reservoirs of toxaphene in agriculture soils and a wide dispersal of residues in the environment. Measurements of toxaphene in coastal areas on the coast of the Pacific Ocean show that environmental concentrations are particularly high in the district of Chinandega, the traditional cotton growing region. Toxaphene residues measured in soils attained 44 microg g(-1) (dry weight) while concentrations in lagoon sediments attained 6.9 microg g(-1) (dry weight) near the mouth of the rivers flowing across the agricultural region. Measurements in aquatic biota showed concentrations as high as 1.6 microg g(-1) (dry weight) in the soft tissues of clams. The toxaphene reservoir in soils combined with the obvious persistence of this compound in soils and lagoon sediments allows predicting that toxaphene will remain in the coastal ecosystem at relatively high concentrations for many years. Toxic effects in lagoon fauna are likely to be observed especially in benthic species that may recycle this compound from sediments. Consumption of seafood, in particular of clams (Anadara spp.) from the more contaminated areas, may expose the population to unacceptably high intake of toxaphene, 30 microg d(-1) per person, with the diet.

Quinine pharmacokinetics in chronic haemodialysis patients

AIMS

Quinine is often used to prevent muscle cramps in patients with chronic renal failure. A standard dose of 300 mg at bedtime is usually recommended, but little is known about the pharmacokinetics of quinine in the presence of renal failure.

METHODS

We studied the pharmacokinetics of quinine in eight normal subjects and eight patients with chronic renal failure on haemodialysis after a single oral dose of quinine sulphate (300 mg).

RESULTS

The concentration of alpha1-acid glycoprotein (AAG), the major binding protein for quinine, was increased in haemodialysis patients compared with control subjects (1.52 g l-1 vs 0.63 g l-1 [mean difference 1.033; 95% CI 0.735, 1.330]) whereas albumin levels were decreased (30 g l-1 vs 40 g l-1 [mean difference 9.5; 95% CI 3.048, 15.952]). Accordingly, the free fraction of quinine was decreased (0.024 vs 0.063 [mean difference 0.0380; 95% CI 0.0221, 0.0539]) and the apparent volume of distribution tended to decrease (0.95 l kg-1 vs 1.43 l kg-1 [mean difference 0.480; 95% CI 0.193, 1.154]). The quinine binding ratio correlated with the plasma concentration of AAG but not that of albumin. The clearance of free (unbound) quinine was increased in haemodialysis patients compared with controls (67.9 ml min-1 kg-1 vs 41.1 ml min-1 kg-1 [mean difference -26.8; 95% CI, -56.994, 3.469]), and the area under the curve (AUC) of the two main metabolites, 3-hydroxyquinine and 10,11-dihydroxydihydroquinine were increased.

CONCLUSIONS

In patients with chronic renal failure, there is an increase in plasma protein binding and in the clearance of free drug, resulting in lower plasma concentration of free quinine.

Global intercomparison for the determination of chlorinated pesticides, PCBs and petroleum hydrocarbons in sediment sample IAEA-417

A world-wide interlaboratory comparison exercise was organised using a lagoon sediment as sample material (IAEA-417) for the analyses of chlorinated pesticides, PCB congeners and petroleum hydrocarbons. The sample material was analysed by 97 laboratories from 46 countries, representing a rather wide distribution for such an interlaboratory comparison exercise. Whereas quite variable results were reported for most chlorinated pesticides, more consistent interlaboratory results were obtained for PCB congeners and polycyclic aromatic hydrocarbons (PAHs). Nevertheless, many laboratories reported results in sufficiently dose agreement that after statistical screening of the data, consensus values were obtained for the concentration of several analytes in this sediment sample. The results allow reference concentration values to be assigned for several analytes. Thus, the sediment sample IAEA-417 can be used as a reference material for quality control of data in the determination of chlorinated compounds and petroleum hydrocarbons in moderately polluted sediments.

Distribution, fate and effects of pesticide residues in tropical coastal lagoons of northwestern Mexico

Analyses of pesticide residues in sediments, water and biota of the Altata-Ensenada del Pabellon coastal lagoon system in Sinaloa, Mexico, showed the presence of organochlorine and organophosphorus compounds. For all the compounds analysed, concentrations in sediments were higher near the points of water discharge from ponds and drainage from the agricultural area. Among the organochlorines, total DDTs displayed the largest sedimentary reservoir, followed by total endosulfans and chlorpyrifos. In sediments, as well as in biota, pp'-DDT concentrations were lower than those of DDT metabolites, which confirms the reduction in the previous massive use of this compound in agriculture. Endosulfan is currently used in the region and endosulfan residues in lagoon sediments attained levels considered to be toxic to meiofauna, therefore constituting an ecological risk to lagoon ecosystems. There was a large sedimentary reservoir of chlorpyrifos but its ecotoxicological risk is difficult to assess due to lack of adequate comparative data. Nevertheless, concentrations of chlorpyrifos which approach acute toxic levels for shrimp were recorded in lagoon water. This suggests that drainage from agricultural fields during high runoff may, on occasion, cause mass mortality of shrimp and fish Organophosphorus pesticides are widely regarded to degrade very rapidly in aquatic systems. Experimental research performed with 14C-labelled chlorpyrifos and parathion has shown that they may be stabilised for relatively long periods of time through sediment-water partitioning. This extension of their environmental half-lives increases their potential for impacting on coastal ecosystems. Since organophosphorus pesticides are highly toxic for aquatic organisms at concentrations generally lower than organochlorines, their presence in the lagoon water and sediment is a matter for much concern. The increased use of tropical coastal lagoons for shrimp and fish farming requires the implementation of environmental management practices to protect these ecosystems from the impact of agricultural activities. Environmental management aims to preserve the ecosystem integrity of these coastal lagoons and, through improving the water quality, to allow the development of aquaculture and reduce human exposure to pesticide residues in food.

Ecological risk assessment of pesticide residues in coastal lagoons of Nicaragua

A detailed investigation on the contamination with chlorinated hydrocarbons and organophosphorous pesticides of the coastal lagoon system of Chinandega district, Nicaragua, allowed the identification of contaminant sources and lagoon areas currently more contaminated. The discharge of rivers into the lagoons is the main transport pathway of pesticide residues; whereas atmospheric depositions are likely to be the main pathway for the introduction of PCBs into the lagoons. Analysis of water samples indicates widespread contamination with soluble organophosphorous compounds, such as dichlorvos, up to 410 ng L(-1), diazinon, up to 150 ng L(-1), and chlorpyrifos, up to 83 ng L(-1). Analyses of suspended matter for low solubility organochlorine (OC) compounds revealed very high concentrations of toxaphene, up to 17,450 ng g(-1) dry weight (dw), total DDTs up to 478 ng g(-1), Aroclor 1254, up to 119 ng g(-1) (dw), and lower concentrations for other compounds. Lagoon sediments contain high concentrations also of toxaphene, from 7.9 to 6,900 ng g(-1) (dw), and DDTs, from 1.5 to 321 ng g(-1) (dw), and lower concentrations of chlorpyrifos, hexachlorocyclohexanes, chlordane and other residues. Concentrations of OCs in soft tissues of clams are statistically correlated with the concentrations of the same compounds in bottom sediments, indicating that sediments are a source of contaminants to biota. In some areas of the lagoon system, concentration of residues in sediments are far above recommended threshold guideline values for protection of aquatic life, and may cause acute and chronic toxic effects on more sensitive aquatic species. Despite the ban on the use of toxaphene and DDT, residues of these compounds are still entering the lagoons due to erosion of, and leaching from, agriculture soils in the region. Measures for protection of the lagoon ecosystem are discussed.

Etiology and outcome of acute liver failure: experience from a liver transplantation centre in Montreal

BACKGROUND

Acute liver failure is a rare condition in which massive liver injury is associated with the rapid development of hepatic encephalopathy. Although viral hepatitis and drug-induced liver injury are the most common causes, no specific etiology is found in a substantial proportion of cases reported from Europe and the United States.

AIM

To determine the etiology and outcome of patients with acute liver failure in the authors' institution.

PATIENTS AND METHODS

The charts of 81 consecutive patients admitted to Saint-Luc between 1991 and 1999 were reviewed.

RESULTS

The etiology was viral in 27 cases (33.2%), toxic or drug-induced in 22 (27.2%), of unknown origin in 22 (27.2%) and due to various causes in 10 (12.3%) (autoimmune, vascular, cancer). Of the 81 patients, 16% survived without liver transplantation, and 84% died or underwent liver transplantation. Survival without liver transplantation differed according to the mode of presentation: the survival rate was 27% in patients with hyperacute liver failure, 7% in those with acute liver failure and 0% in those with subacute liver failure. Among the 38 patients who underwent liver transplantation, survival one year after transplantation was 71%. In the 30 patients who died without liver transplantation, the main causes of death were cerebral edema and sepsis.

CONCLUSIONS

Acute liver failure is associated with a high mortality, and liver transplantation is the treatment of choice. In a significant proportion of cases, the etiology remains undetermined and is probably related to yet unidentified hepatotropic viruses.

Persistent organochlorine residues in sediments from the Black Sea

The extent of contamination of the Black Sea by selected organochlorine compounds has been assessed through the analysis of surficial sediments taken from throughout the region. Concentrations of HCHs at sites influenced by the Danube delta are among the highest recorded on a global basis (up to 40 ng g(-1) dry wt). The ratio between the alpha- and gamma-isomers was relatively low indicating contamination through the use of lindane. Concentrations of DDTs (0.06-72 ng g(-1) dry wt) and PCBs (0.06-72 ng g(-1) dry wt) were not especially high in comparison to levels reported from throughout the world. The DDE/DDT ratio was, however, low indicating fresh inputs and hence current usage of DDT within the Black Sea region.

Petroleum and PAH contamination of the Black Sea

Concern has been expressed regarding the extent of contamination of the Black Sea. Analyses of coastal sediments taken from throughout the region indicate, however, that levels of petroleum hydrocarbons (2-300 microg g(-1) dry wt total hydrocarbons) are generally comparable to those encountered in the Mediterranean and are lower than concentrations reported for highly contaminated areas such as the Gulf, Hong Kong, Taiwan and New York Bight. Highest concentrations of total hydrocarbons (>100 microg g(-1) dry wt) were associated with discharges from Odessa, Sochi and the River Danube. Chronic/degraded petroleum was the major contributor at these sites. Samples from the Ukrainian coastline were comparatively clean (<10 microg g(-1) dry wt total hydrocarbons). Major contributions of fresh oil (as indicated by sigma n-C14-34) occur through the River Danube. Concerning total PAH, concentrations (7-638 ng g(-1) dry wt) compare to relatively unpolluted locations in the Mediterranean and are much lower than levels reported for polluted UK estuaries (e.g. Mersey, Tyne, Thames). Both pyrolytic and petrogenic PAH are present in most samples, although petroleum derived PAH are dominant at Sochi and pyrolytic sources are prevalent in the Bosphorus region. The absence of a correlation between total hydrocarbons and PAH (R2 = 0.04) indicates different primary sources for the two.

Development of a risk-based TMDL assessment approach using the integrated modeling system GIBSI

Using the integrated modeling system GIB SI and a case study, this paper presents the development of a risk-based TMDL assessment approach that links wet (nonpoint/diffuse) and dry weather (point) sources to a probability of exceeding water quality standards (WQS) governing wateruses. The case study focused on determining whether WQS defining recreational uses of water requiring direct and prolonged contact were attainable if the waste water effluent of a small town was treated using aerated lagoons and if the agricultural nonpoint source (NPS) loads were reduced using different fertilization rates. Dry weather sources were assumed to solely contribute to bacteriological impairment of the studied river reach. Meanwhile, both wet and dry weather sources were assumed to contribute to aesthetic impairment. Simulation results showed that treating the waste water effluent while reducing the agricultural NPS loads by 27% allowed on average over a four-year study period for attainment of the bacteriological WQS 100% of the summer time while lowering the probability of exceeding the aesthetic WQS from 0.32 to 0.19 (30 to 18 days). The results of this study showed this risk-based assessment approach was well suited to establish TMDL. These probabilities should be evaluated using long meteorological series.

An unusual case of hepatic abscess

A case of recurring primary hepatic actinomycosis is reported. A 50-year-old man presented with fever, weight loss and multiple hepatic masses. A diagnosis was obtained by cytological examination of a biopsy sample taken from the largest hepatic mass, which revealed the presence of Actinomyces species. The patient was treated with penicillin for 12 months and did well. Seven years later, he presented with similar symptoms but with a single large liver mass and a pulmonary infiltrate in the right lower lobe. Liver biopsy showed an inflammatory pseudotumour, and lung biopsy showed the presence of Actinomyces species. Again, the patient was treated with penicillin. Five months later, the patient was doing well, and a follow-up computed tomography scan showed partial regression of the hepatic pseudotumour. This case indicates that hepatic actinomycosis can recur several years after an appropriate treatment and stresses the need for careful follow-up in such patients.

Differential alteration of cytochrome P450 isoenzymes in two experimental models of cirrhosis

Liver diseases are associated with a decrease in hepatic drug elimination, but there is evidence that cirrhosis does not result in uniform changes of cytochrome P450 (CYP) isoenzymes. The objective of this study was to determine the content and activity of four CYP isoenzymes in the bile duct ligation and carbon tetrachloride (CCl4)-induced models of cirrhosis. The hepatic content of CYP1A, CYP2C, CYP2E1, and CYP3A was measured by Western blot analysis. CYP activity in vivo was evaluated with breath tests using substrates specific for different isoenzymes: caffeine (CYP1A2), aminopyrine (CYP2C11), nitrosodimethylamine (CYP2E1), and erythromycin (CYP3A). Bile duct ligation resulted in biliary cirrhosis; CYP1A, CYP2C and CYP3A content was decreased and the caffeine, aminopyrine, and erythromycin breath tests were reduced whereas CYP2E1 content and the nitrosodimethylamine breath test were unchanged compared with controls. CCl4 treatment resulted in cirrhosis of varying severity as assessed from the decrease in liver weight and serum albumin. In rats with mild cirrhosis, CYP content was comparable with controls except for a decrease in CYP2C. The activity of CYPs was also unchanged except for an increase in CYP2E1 activity. In rats with more severe cirrhosis, the content of all four CYP isoenzymes and the caffeine, aminopyrine, and erythromycin breath tests were reduced whereas the nitrosodimethylamine breath test was unchanged. In both models of cirrhosis, there was a significant correlation between the breath tests results and the severity of cirrhosis as assessed from serum albumin levels. These results indicate that content and the catalytic activity of individual CYP enzymes are differentially altered by cirrhosis in the rat and also suggest that drug probes could be useful to assess hepatic functional reserve.

Transjugular intrahepatic portosystemic shunt (TIPS) versus endoscopic variceal ligation in the prevention of variceal rebleeding in patients with cirrhosis: a randomised trial

BACKGROUND AND AIMS

The transjugular intrahepatic portosystemic shunt (TIPS) is a new therapeutic modality for variceal bleeding. In this study we compared the two year survival and rebleeding rates in cirrhotic patients treated by either variceal band ligation or TIPS for variceal bleeding.

METHODS

Eighty cirrhotic patients (Pugh score 7-12) with variceal bleeding were randomly allocated to TIPS (n=41) or ligation (n=39), 24 hours after control of bleeding.

RESULTS

Mean follow up was 581 days in the ligation group and 678 days in the TIPS group. The two year survival rate was 57% in the TIPS group and 56% in the ligation group (NS); the incidence of variceal rebleeding after two years was 18% in the TIPS group and 66% in the ligation group (p<0.001). Uncontrolled rebleeding occurred in 11 patients in the ligation group (eight were rescued by emergency TIPS) but in none of the TIPS group. The incidence of encephalopathy at two years was 47% in the TIPS group and 44% in the ligation group (NS).

CONCLUSIONS

TIPS did not increase the two year survival rate compared with variceal band ligation after variceal bleeding in cirrhotic patients with moderate or severe liver failure. It significantly reduced the incidence of variceal rebleeding without increasing the rate of encephalopathy.

Furosemide-induced natriuresis as a test to identify cirrhotic patients with refractory ascites

The diagnosis of refractory ascites in cirrhotic patients carries a poor prognosis and liver transplantation should always be considered in this situation. Identification of patients who will not respond to diuretic therapy usually requires several weeks of observation during which a trial of diuretics is instituted using stepwise increases in dosage in order to classify ascites as refractory. In the present study we evaluated the effect of a single dose of 80 mg intravenous furosemide on urinary sodium excretion over 8 hours in cirrhotic patients with ascites responsive to diuretic treatment (group 1; n = 14) and patients with refractory ascites (group 2; n = 15). The test was performed after 3 days without diuretics and patients were on a 80 mEq sodium/day diet. Refractory ascites was defined by the absence of response after 3 months of high doses of diuretics (spironolactone 200 mg/d + furosemide 80 mg/d + metolazone 2.5 mg/d) and the need for repeated paracentesis. The two groups had similar degrees of liver and renal dysfunction as assessed by the Pugh score and creatinine clearance. The effects of furosemide on 8-hour natriuresis was much higher in patients with responsive ascites as compared with patients with refractory ascites (125 +/- 46 vs. 30 +/- 16 mEq; mean +/- SD; P <.0001). A natriuresis lower than 50 mEq/8 hours was observed in all group-2 patients as compared with none from group 1. The present study shows that patients with refractory ascites can be identified quickly and accurately by using this simple furosemide-induced natriuresis test, which could be very useful to select patients for liver transplantation.

Chlorinated pesticides and PCBs in sediments and molluscs from freshwater canals in the Hanoi region

The concentrations of organochlorine pesticides and PCBs were determined in surface sediments and freshwater molluscs (Angulyagra sp.) from water canals in the region of Hanoi city. Results obtained show that the concentration of sigma DDT compounds in sediments range from 7 to 80 ng/g (dry weight) and from 6 to 864 ng/g (dry weight) in the soft tissues of molluscs. The concentrations of sigma DDTs were higher in populated sites and much lower in rural sites, indicating that the DDT has been used for mosquito control and not as a crop protection chemical. Hexachlocyclohexanes (HCHs) have also been widely used in the region but the current environmental concentrations are much lower than those of DDT's, which is due to the less persistence of those compounds. Polychlorinated biphenyls (PCBs) were measured, for example as aroclor 1254, in concentrations up to 40 ng/g (dry weight) and up to 76 ng/g (dry weight) in sediments and molluscs, respectively. Molluscs from water canals are a very popular food in the region. Taking into consideration the high DDT levels measured in these molluscs their consumption is worrisome and may expose the population to high levels of endocrine disrupting substances. Current PCB levels in sediments are lower than usually measured in industrialized countries. Therefore, PCB concentrations in aquatic molluscs are still also relatively low. These snails do not have enzyme ability to metabolize most of the CB congeners and, thus, are passive accumulators and a significant transfer pathway of CBs to consumers. Therefore, measures to phase out the use of these persistent and bioaccumulable chemicals should be adopted in order to prevent further environmental contamination.

Decreased in vivo metabolism of drugs in chronic renal failure

Chronic renal failure (CRF) is associated with a decrease in renal excretion of drugs, but its effects on the liver metabolism of xenobiotics are poorly defined. The objectives of this study were to determine the effects of CRF on hepatic cytochrome P450 (CYP450) and its repercussions on in vivo hepatic metabolism of drugs. Two groups of rats were studied: control paired-fed and CRF. CRF was induced by subtotal nephrectomy. Total CYP450 activity and protein expression of several CYP450 isoforms (CYP1A2, CYP2C11, CYP3A1, CYP3A2) were assessed in liver microsomes. In vivo cytochrome P450 activity was evaluated with breath tests using substrates for different isoenzymes: caffeine (CYP1A2), aminopyrine (CYP2C11), and erythromycin (CYP3A2). Creatinine clearance was reduced by 60% (P <. 01) in rats with CRF. Compared with control paired-fed rats, total CYP450 activity was reduced by 40% in rats with CRF. Protein expression of CYP2C11, CYP3A1, and CYP3A2 was considerably reduced (more than 45%, P <.001) in rats with CRF, whereas the levels of CYP1A2 were unchanged. In rats with CRF, there was a 35% reduction in the aminopyrine (CYP2C11) and the erythromycin (CYP3A2) breath tests compared with control animals (P <.001). The caffeine (CYP1A2) breath tests remained comparable to controls. Creatinine clearance correlated with the aminopyrine and erythromycin breath tests (r(2) = 0.73 and r(2) = 0.81, respectively, P <.001). In conclusion, CRF is associated with a decrease in total liver CYP450 activity in rats (mainly in CYP2C11, CYP3A1, and CYP3A2), which leads to a significant decrease in the metabolism of drugs.