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Biomedical subjects

Emmet B Keeffe

Publications and source records attributed to Emmet B Keeffe.

At least 55 records · Page 3Linked to original sources
PubMed2004

Epidemiology and pathogenesis of primary biliary cirrhosis.

Primary biliary cirrhosis is an autoimmune disease of unknown etiology leading to progressive destruction of small intrahepatic bile ducts and eventually to liver cirrhosis and failure. It is characterized by female predominance (with most cases observed between the ages of 40 and 60) and serum autoantibodies to mitochondrial antigens as highly specific hallmarks. Epidemiologic data indicate a variable incidence and prevalence of the disease. A number of genetic factors have been indicated as playing a role in determining disease susceptibility or progression, although no definitive conclusion has been reached so far. However, as suggested by some epidemiologic observations, a number of environmental factors, including molecular mimicry by either microorganisms or xenobiotics, have also been proposed. A hypothesis gaining support is that environmental factors may trigger disease in genetically predisposed individuals. In this review, the available data regarding the epidemiology and pathogenesis of primary biliary cirrhosis will be described and discussed.

Humans↗
PubMed2004

Epidemiology and treatment outcomes of patients with chronic hepatitis C and genotypes 4 to 9.

Pivotal clinical trials of antiviral therapy for chronic hepatitis C have been conducted predominantly in Europe and the United States, where most patients are infected with genotypes 1, 2, or 3. As a result, published data on the outcomes of therapy in patients infected with genotypes 4, 5, and 6 to 9 are limited. However, a major proportion of patients with chronic hepatitis C worldwide reside in geographic areas where genotypes 4 (Africa and the Middle East), 5 (South Africa), or 6 to 9 (southern China and Southeast Asia) are prevalent or even the most common genotypes. The epidemiology of hepatitis C virus genotypes 4 to 9 is reviewed, and the studies reporting the results of antiviral therapy of these genotypes are summarized. The limited data on antiviral therapy in patients with genotypes 4 to 9 highlight the need for further and controlled treatment trials in these populations.

Africa↗
PubMed2004

Retreatment of chronic hepatitis C virus infection.

Despite advances in antiviral therapy for chronic hepatitis C, approximately half of patients undergoing initial treatment fail to achieve a sustained virologic response (SVR), thus prompting consideration of retreatment with alternative regimens. The decision to re-treat should be based on the severity of liver disease, as well as the presence of clinical and virologic predictors of a successful outcome of additional therapy. Retreatment of patients who were prior nonresponders to interferon monotherapy with interferon plus ribavirin results in SVR rates of 13% to 15%, which can be increased to 25% to 40% if peginterferon plus ribavirin is used. Retreatment of patients who were prior nonresponders to interferon plus ribavirin with peginterferon plus ribavirin unfortunately achieves SVR rates of approximately 10%. The growing number of patients who have been treated and have failed initial therapy highlights the need for the development of more efficacious antiviral agents for the treatment of chronic hepatitis C.

Antiviral Agents↗
PubMed2004

Management of antiviral resistance in patients with chronic hepatitis B.

A meeting of physicians and scientists involved in the management of chronic hepatitis B (CHB) was held to review current scientific data regarding antiviral resistance in hepatitis B virus (HBV) infection. The goals of the meeting were to describe current treatments for CHB, discuss emerging issues in HBV drug resistance and to delineate patient monitoring, including markers for resistance, during administration of antiviral therapy. The aim of this review article is to provide treating physicians with a framework for the management of CHB in the context of antiviral resistance. Definitions of primary and secondary antiviral treatment failure can be used to aid monitoring and early diagnosis of drug resistance before disease progression occurs as a consequence of viral breakthrough. Primary antiviral treatment failure is defined as failure of a drug to reduce HBV DNA levels by > or = 1 x log10 IU/ml within 3 months following initiation of therapy, and secondary antiviral treatment failure as a rebound of HBV replication of > or = 1 x log10 IU/ml from nadir in patients with an initial antiviral treatment effect (> or = 1 x log10 IU/ml decrease in serum HBV DNA). Confirmation of antiviral drug failure can be established by sequencing the HBV DNA polymerase and identifying specific genetic markers of antiviral drug resistance. In addition to virological assays, HBV resistance can be assessed from a clinical perspective including increased serum alanine aminotransferase levels and the development of systemic symptoms or signs of liver failure. Potential strategies to prevent the emergence of resistance and how to manage drug-resistant HBV once it emerges are discussed.

Antiviral Agents↗
PubMed2003

Keratin 8 and 18 mutations are risk factors for developing liver disease of multiple etiologies.

Keratin 8 and 18 (K8K18) mutations are found in patients with cryptogenic cirrhosis, but the role of keratin mutations in noncryptogenic cirrhosis and the incidence of keratin mutations in the general population are not known. We screened for K8K18 mutations in genomic DNA isolated from 314 liver explants of patients who primarily had noncryptogenic cirrhosis, and from 349 blood bank volunteers. Seven unique K8K18 mutations were found in 11 independent patients with biliary atresia, hepatitis BC, alcohol, primary biliary cirrhosis, and fulminant hepatitis. Seven of the 11 patients had mutations previously described in patients with cryptogenic cirrhosis: K8 Tyr-53 --> His, K8 Gly-61 --> Cys, and K18 His-127 --> Leu. The four remaining patients had mutations at one K8 and three other K18 new sites. Of the 349 blood bank control samples, only one contained the Tyr-53 --> His and one the Gly-61 --> Cys K8 mutations (P < 0.004 when comparing cirrhosis versus control groups). Two additional mutations were found in both the liver disease and blood bank groups and, hence, likely represent polymorphisms. Livers with keratin mutations had cytoplasmic filamentous deposits that were less frequent in livers without the mutations (P = 0.03). Therefore, K8K18 are likely susceptibility genes for developing cryptogenic and noncryptogenic forms of liver disease.

Cohort Studies↗
PubMed2003

Update on chronic hepatitis C.

Strategies for the diagnosis and treatment of chronic hepatitis C continue to evolve. Liver biopsy is now used selectively rather than routinely, and the combination peginterferon plus ribavirin is the treatment of choice for the majority of patients.

Antiviral Agents↗
PubMed2003

Hepatitis B virus genotypes in the United States: results of a nationwide study.

BACKGROUND & AIMS: Hepatitis B virus (HBV) genotypes may be related to severity of liver disease and treatment response. The aims of this nationwide study were to determine the prevalence of HBV genotypes in the United States and the association between HBV genotypes and patient demographics, mode of infection, and clinical status. METHODS: A total of 694 consecutive chronic HBV-infected patients seen in 17 U.S. liver centers during a 1-year period were enrolled. Demographic, clinical, and laboratory data were collected. Sera were tested for HBV genotyping, precore, and core promoter variants by line-probe assays. RESULTS: All 7 HBV genotypes (A-G) were found, with genotypes A and C the most common. The prevalence of HBV genotypes was different in different regions of the United States. A strong correlation was found between HBV genotypes and ethnicity. HBV genotype A was prevalent among white and black patients, whereas genotypes B and C were most common among Asian patients. The predominant genotype among patients born in the United States, Europe, the Far East, and Southeast Asia were A, D, C, and B, respectively. Genotypes A and C were associated with a higher prevalence of hepatitis B e antigen. Precore variant was detected in 27% of patients and core promoter variant in 44% of patients. CONCLUSIONS: Our study suggests that the epidemiology of HBV infection in the United States may have changed over time as a result of immigration from countries with a high prevalence of HBV infection. HBV genotypes may account for the heterogeneity in disease manifestations among patients with chronic HBV infection.

Adolescent↗
PubMed2003

Liver-infiltrating lymphocytes in end-stage hepatitis C virus: subsets, activation status, and chemokine receptor phenotypes.

BACKGROUND: Hepatitis C virus (HCV) is a leading cause of chronic liver disease, yet little is known about the intrahepatic immune response in end-stage patients. Chemokines and their receptors are important regulators of immunity, particularly in the migration and localization of circulating leukocytes within peripheral tissues. AIMS: This report provides a comprehensive comparison of the chemokine receptor and activation phenotype of the major leukocyte subsets present in end-stage HCV-infected and non-HCV infected livers. METHODS: Lymphocytes were purified from homogenized explant liver tissue and analyzed by flow cytometry. RESULTS: NK cells are the predominant cell type, followed by T cells, B cells and NK-T cells, independent of HCV status. T cells displayed a memory phenotype and low levels of activation markers. CCR5, CXCR3 and CXCR6 were expressed on a large fraction of activated cells, while moderate to low expression of CCR2, CCR6 and CX(3)CR1 was observed. Several other tissue-specific and inflammatory chemokine receptors were absent from infiltrating lymphocytes. CONCLUSIONS: These results identify the chemokine receptors present on infiltrating lymphocytes during end-stage liver disease and suggest that such infiltration is predominantly controlled by non-tissue-specific inflammatory chemokines, a situation that may be distinct from liver homing pathways under normal conditions.

Biomarkers↗
PubMed2003

Nucleoside analogues and other antivirals for treatment of hepatitis B in the peritransplant period.

Chronic HBV infection is a common cause of advanced liver disease that is associated with substantial mortality. Furthermore, chronic hepatitis B was historically a controversial indication for liver transplantation because of a low post-transplant survival, with graft infection being the major contributor to adverse outcomes. The initial use of hepatitis B immune globulin as prophylaxis, followed later by combined therapy with lamivudine, markedly reduced viral recurrence and improved the survival of patients transplanted for acute or chronic hepatitis B with liver failure. Lamivudine alone can also be used for long-term prophylaxis against de novo HBV infection that can be transmitted by organs from donors positive for anti-HBc or anti-HBs. When used in patients with decompensated chronic hepatitis B with cirrhosis, lamivudine has been shown to improve clinical manifestations, prolong pretransplant survival, and defer, or even obviate, the need for transplantation. Despite prophylaxis, viral mutations with breakthrough reinfection may occur and lead to liver failure. The recently approved adefovir dipivoxil, which is active against lamivudine-resistant mutation, and other nucleoside analogs that are in various phases of development, offer hope as rescue therapy for viral recurrence. Other therapeutic alternatives in the future may include gene therapy and immune interventions.

Adenine↗
PubMed2003

Pathogenesis of primary biliary cirrhosis.

Primary biliary cirrhosis is an enigmatic autoimmune disease that predominantly affects women. The serologic signatures of PBC are high titer antimitochondrial antibodies that are directed at the inner lipoyl domains of the 2-oxo-dehydrogenase enzymes, particularly PDC-E2. Of note, is that the antibody response and the CD4 and CD8 response, are all directed at a similar epitope, the inner lipoyl domain. This unique immunologic response suggests that modification of the inner lipoyl domain is associated with the immunogenetic basis of disease.

Apoptosis↗
PubMed2003

Prevalence of HBV precore/core promoter variants in the United States.

Variants in the precore (G(1896)A) and core promoter (A(1762)T, G(1764)A) regions of hepatitis B virus (HBV) may be related to serum HBV DNA levels and severity of liver disease. The aims of this nationwide study were to determine the prevalence of HBV precore/core promoter variants in the United States and the association between these variants and patient demographics, HBV genotypes, serum HBV DNA level, and severity of liver disease. A total of 694 consecutive chronic HBV-infected patients seen in 17 U.S. liver centers during a 1-year period were enrolled. Demographic, clinical, and laboratory data were collected. Sera were tested for HBV genotypes as well as precore and core promoter variants by line-probe assays. Quantitative HBV DNA levels were determined using Cobas Amplicor HBV Monitor kits. Precore and core promoter variants were found in 27% and 44% of patients with chronic HBV infection in the United States. Precore and core promoter variants were more common in hepatitis B e antigen (HBeAg)-negative than in HBeAg-positive patients (precore, 38% vs. 9%; core promoter, 51% vs. 36%; respectively, P <.001). The prevalence of these variants was related to ethnicity, place of birth, and HBV genotypes. Patients with core promoter variants were more likely to have hepatic decompensation. Precore and/or core promoter variants were associated with higher serum HBV DNA levels in HBeAg-negative but not in HBeAg-positive patients. In conclusion, HBV precore and core promoter variants are not rare in the United States. Physicians should be aware of the existence of HBV precore and core promoter variants and the clinical condition of "HBeAg-negative chronic hepatitis."

Adult↗
PubMed2003

The epidemiology of hepatitis C virus infection.

The prevalence of hepatitis C virus (HCV) infection varies in different populations, ranging from as low as 0.6% in volunteer blood donors to as high as 80% in injection drug users. The prevalence of HCV in a population can be predicted by risk factors associated with the transmission of infection. These risk factors include injection drug use, blood product transfusion, organ transplantation, hemodialysis, occupational injury, sexual transmission, and vertical transmission. We review the literature regarding the incidence and prevalence of HCV infection and the evidence supporting various modes of HCV transmission.

Hepatitis C↗
PubMed2003

Prophylaxis against chemotherapy-induced reactivation of hepatitis B virus infection with Lamivudine.

The results of lamivudine therapy in 4 patients with chemotherapy-induced hepatitis B virus (HBV) reactivation are reported. Cancer chemotherapy-induced reactivation is a known complication in patients with chronic HBV infection or history of HBV infection with recovery. Reactivation of HBV infection has a broad spectrum of manifestations ranging from mild elevation of aminotransferase levels to fatal fulminant hepatitis. Lamivudine is a nucleoside analogue and a potent inhibitor of HBV reverse transcription. The 4 patients treated with lamivudine included 1 woman with breast cancer and 3 men with non-Hodgkin lymphoma, ranging from 41 to 63 years of age. All 4 patients were undergoing standard, multi-agent chemotherapy when they presented with HBV reactivation manifested by sudden onset of fatigue, jaundice, and HBV serology consistent with active HBV infection (detectable serum HBV DNA) in the absence of other known causes of acute hepatitis. Lamivudine therapy (100 mg/d in 3 patients and 150 mg/d in 1 patient) was initiated from 1 to 18 days following the diagnosis of HBV reactivation. All 4 patients showed rapid decrease in aminotransferase levels within 2 weeks after initiating lamivudine therapy. Unfortunately, hepatic synthetic function failed to improve in 2 patients, who both died. The remaining 2 patients had suppression of HBV DNA to undetectable levels after 1 and 4 months of treatment and had biochemical and clinical improvement. The 2 patients who died received lamivudine therapy for 8 days and for 3 weeks. There have been no randomized clinical trials to study the role of lamivudine for prophylaxis or treatment of HBV reactivation associated with chemotherapy. However, based on our limited experience, lamivudine may be efficacious in suppressing potentially fatal HBV reactivation secondary to chemotherapy in patients with chronic HBV infection or prior infection with recovery. Patients who undergo chemotherapy should be screened for the presence of markers of chronic hepatitis B infection or previous HBV infection. We recommend that patients with chronic HBV infection (positive HBV DNA and/or positive HBsAg) or history of HBV infection with recovery (positive hepatitis B core antibody with or without HBsAb) be considered for prophylactic lamivudine use to prevent chemotherapy-induced HBV reactivation.

Adult↗