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Biomedical subjects

R Esteban

Publications and source records attributed to R Esteban.

At least 55 records · Page 3Linked to original sources
PubMed1998

Recurrent hepatitis C virus infection after liver transplantation: immunohistochemical assessment of the viral antigen.

BACKGROUND: The value of immunohistochemical methods to identify hepatitis C virus antigen (HCVAg) in liver tissue has not been established. We have evaluated the significance of HCVAg expression in livers of patients with transplants and recurrent hepatitis C virus (HCV) infection. METHODS: Forty-two liver biopsy specimens from 32 liver-transplant recipients with recurrent HCV infection were tested for HCVAg using fluorescein isothiocyanate-labeled polyclonal, polyreactive human immunoglobulin. Histologic assessment of liver and quantitation of HCV RNA in sera were carried out in specimens obtained simultaneously with biopsies. RESULTS: HCVAg was found in 33% of the liver specimens obtained during the first month after transplantation and in all liver specimens obtained between 1 and 18 months after transplantation. Amounts of the antigen were significantly greater in specimens obtained more than 1 month after transplantation. A statistically significant increase of the average HCV RNA level in serum was observed in samples tested after the first month after the transplantation, and some decrease in the HCV RNA level was found in those obtained between 6 and 18 months after transplantation. Larger amounts of HCVAg were observed in specimens corresponding to episodes of acute or chronic hepatitis than in those associated with minimal parenchymal evidence of rejection. CONCLUSIONS: OBSERVATIONS of HCVAg expression in liver biopsy specimens indicated that the presence of viral antigens in hepatocytes is a constant finding in specimens obtained 1 month or longer after transplantation. Although large amounts of HCVAg correlated with acute or chronic hepatitis, the nature of this association with the development of pathologic changes remains to be established.

Adult↗
PubMed1998

Transient emergence of hepatitis B variants in a patient with chronic hepatitis B resistant to lamivudine.

BACKGROUND: Lamivudine is a cytosine nucleoside analogue that inhibits hepatitis B virus replication. Resistance to lamivudine monotherapy has been reported in patients who received lamivudine to prevent recurrent hepatitis B virus infection after liver transplantation. No cases of resistance have been described in patients who did not clear HBV DNA during lamivudine therapy. METHODS: We report the case of an adult patient with chronic HBeAg-positive hepatitis B who had a hepatitis flare during lamivudine therapy. The patient did not respond to lamivudine and, at 4 months of treatment, developed a significant serum alanine aminotransferase elevation. Alanine aminotransferase levels remained elevated for 4 months and returned to baseline spontaneously. Lamivudine therapy was administered for 1 year (52 weeks) and after withdrawal, alanine aminotransferase levels remained elevated. RESULTS: Sequencing studies of HBV DNA at week 52 showed the emergence of a lamivudine-resistant variant associated with two point mutations in the hepatitis B virus polymerase gene: one mutation led to amino acid substitution of methionine to valine at residue 552, in the highly conserved tyrosine-methionineaspartate-aspartate motif, part of the active site of the polymerase; the second mutation consisted of a substitution of leucine to methionine at residue 528. At week 54 of follow-up, both mutations were undetectable. CONCLUSION: This observation demonstrates the transient emergence of HBV variants in the course of therapy in a patient resistant to lamivudine therapy.

Adult↗
PubMed1998

Hepatitis delta genotypes in chronic delta infection in the northeast of Spain (Catalonia).

BACKGROUND/AIMS: Based on genetic analysis of variants obtained around the world, three genotypes of the hepatitis delta virus have been defined. Hepatitis delta virus variants have been associated with different disease patterns and geographic distributions. To determine the prevalence of hepatitis delta virus genotypes in the northeast of Spain (Catalonia) and the correlation with transmission routes and clinical disease, we studied the nucleotide divergence of the consensus sequence of HDV RNA obtained from 33 patients with chronic delta hepatitis (24 were intravenous drug users and nine had no risk factors), and four patients with acute self-limited delta infection. METHODS: Serum HDV RNA was amplified by the polymerase chain reaction technique and a fragment of 350 nucleotides (nt 910 to 1259) was directly sequenced. RESULTS: Genetic analysis of the nucleotide consensus sequence obtained showed a high degree of conservation among sequences (93% of mean). Comparison of these sequences with those derived from different geographic areas and pertaining to genotypes I, II and III, showed a mean sequence identity of 92% with genotype I, 73% with genotype II and 61% with genotype III. At the amino acid level (aa 115 to 214), the mean identity was 87% with genotype I, 63% with genotype II and 56% with genotype III. Conserved regions included the RNA editing domain, the carboxyl terminal 19 amino acids of the hepatitis delta antigen and the polyadenylation signal of the viral mRNA. CONCLUSIONS: Hepatitis delta virus isolates in the northeast of Spain are exclusively genotype I, independently of the transmission route and the type of infection. No hepatitis delta virus subgenotypes were found, suggesting that the origin of hepatitis delta virus infection in our geographical area is homogeneous.

Adolescent↗
PubMed1998

Listeria monocytogenes-associated acute hepatitis in a liver transplant recipient.

We report a case of Listeria monocytogenes bacteriemia with liver involvement mimicking acute viral hepatitis in a liver transplant recipient. The patient presented with fever, jaundice and alanine aminotransferase levels ten times the upper limit of normal. Liver biopsy showed signs of acute hepatitis and occasional granulomas. Both blood and liver biopsy cultures were positive for Listeria monocytogenes. The patient received a 3 week course of ampicillin and gentamicin with clinical and biochemical recovery. Liver involvement during Listeria infections is unusual, and most cases occur in patients with underlying hepatic disease and impaired cell-mediated immunity. To our knowledge only one such case has previously been reported in a liver transplant patient. Furthermore, in the present case we isolated the causal agent from the liver biopsy specimen.

Ampicillin↗
PubMed1998

[Cost effectiveness of the treatment of chronic hepatitis C with interferon-alpha].

The purpose of this study was to assess the cost-effectiveness of the treatment of chronic hepatitis C with interferon in Spain. Disease progression was studied using a Markov model through which an untreated cohort of 1000 patients was compared with cohorts treated with interferon 3 MU three times per week for 6, 12 or 18 months. Treatment cost, patients quality of life, and survival were the parameters evaluated. Using the perspective of the National Health System, an 18 month treatment with alfa interferon offers a better cost-effectiveness ratio than a treatment of 6 or 12 months duration. The age of the patient at the start of treatment is one of the most influential factors on the cost-effectiveness of treatment. In patients under 45 years of age, a net cost saving is observed with all treatment schedules, especially with 18 months treatment, due to significant reductions in severe complications of disease progression. In patients aged 45-60, 18 months treatment incurs a net cost, although important gains are made in survival and quality of life. In patients over 65 years of age, the economic benefits of prolonged treatment do not compensate the extra cost. In conclusion, treatment of chronic hepatitis C with alfa interferon should begin as early as possible, especially in young patients. In cases of favourable response, treatment should be extended to 18 months, in order to obtain a higher rate of sustained response, avoid progression of hepatic disease and achieve a more favourable cost-effectiveness ratio.

Adult↗
PubMed1997

Tyrosine kinase inhibition ameliorates the hyperdynamic state and decreases nitric oxide production in cirrhotic rats with portal hypertension and ascites.

Tumor necrosis factor-alpha (TNF) causes vasodilatation and a hyperdynamic state by activating nitric oxide (NO) synthesis. Tyrphostins, specific inhibitors of protein tyrosine kinase (PTK), block the signaling events induced by TNF and NO production. A hyperdynamic circulatory syndrome (HCS) is often observed in portal hypertension (PHT). TNF and NO seem to mediate these hemodynamic changes. The aim of this work was to study the effect of PTK inhibition on the systemic and portal hemodynamics, TNF and NO production, in cirrhotic rats with portal hypertension. Rats with liver cirrhosis induced by chronic inhalation of carbon tetrachloride were used. Animals were treated daily with tyrphostin AG 126 (alpha-cyano-(3-hydroxy-4-nitro) cinnamonitrile) or placebo for 5 d. Mean arterial pressure (MAP), heart rate (HR), and portal pressure (PP) were measured by indwelling catheters. Cardiac output (CI) and stroke volume (SV) were estimated by thermodilution, systemic vascular resistance (SVR) was calculated (MAP/CI), and portal systemic shunting (PSS) was quantitated using radioactive microspheres. Serum and mesenteric lymph node (MLN) TNF levels were measured using an immunoassay kit, and serum NOx was determined photometrically by its oxidation products. The AG 126-treated group showed a statistically significant increase in MAP and SVR, and decreases in CI, SV, MLN TNF, and serum NO oxidation products nitrite and nitrate (NOx) in comparison with the placebo-treated rats. No significant differences were noticed in HR, PP, PSS, or serum TNF. Significant correlations were observed between MAP and NOx, MAP and MLN TNF, PSS and NOx, and serum TNF and serum NOx. The HCS observed in PHT seems to be mediated, at least in part, by TNF and NO by the activation of PTKs and their signaling pathways. PTK activity inhibition ameliorates the hyperdynamic abnormalities that characterize animals with cirrhosis and PHT.

Animals↗
PubMed1997

Structure of replicating hepatitis C virus (HCV) quasispecies in the liver may not be reflected by analysis of circulating HCV virions.

We have analyzed the population of hepatitis C virus (HCV) sequences in paired liver and serum samples from four patients with chronic hepatitis C. Sequences from three different biopsy specimens from a liver explant from one patient were compared with each other and with the circulating sequences. Our results demonstrate that the circulating quasispecies does not necessarily reflect the viral population replicating in the liver and that this is not due to a macroscopic anatomic compartmentalization of HCV replication. This finding has important implications for the pathogenesis and natural history of chronic HCV infection.

Chronic Disease↗
PubMed1997

RNA-dependent RNA polymerase activity associated with the yeast viral p91/20S RNA ribonucleoprotein complex.

20S RNA is a noninfectious viral single-stranded RNA found in most laboratory strains of the yeast Saccharomyces cerevisiae. 20S RNA encodes a protein of 91 kDa (p91) that contains the common motifs found among RNA-dependent RNA polymerases from RNA viruses. p91 and 20S RNA are noncovalently associated in vivo, forming a ribonucleoprotein complex. We detected an RNA polymerase activity in p91/20S RNA complexes isolated by high-speed centrifugation. The activity was not inhibited by actinomycin D nor alpha-amanitin. The majority of the in vitro products was 20S RNA and the rest was the complementary strands of 20S RNA. Because the extracts were prepared from cells accumulating 20S RNA over its complementary strands, these in vitro products reflect the corresponding activities in vivo. When the p91/20S RNA complexes were subjected to sucrose gradient centrifugation, the polymerase activity cosedimented with the complexes. Furthermore, an RNA polymerase activity was detected in the complex by an antibody-linked polymerase assay using anti-p91 antiserum, suggesting that p91 is present in the active RNA polymerase machinery. These results together indicate that p91 is the RNA-dependent RNA polymerase or a subunit thereof responsible for 20S RNA replication.

Amanitins↗
PubMed1997

[Study of HLA-II antigens in chronic hepatitis C and B and in acute hepatitis B].

The aim of this study was to analyze the variability of the HLA-II system in a series of patients with chronic hepatitis B, chronic hepatitis C and acute hepatitis B to know whether there is any relationship between the polymorphism of the HLA system, the different types of hepatitis and the evolution of the infection. HLA-II antigens were determined by a PCR technique in serum samples of 24 controls, 22 cases of chronic hepatitis C, 38 cases of chronic hepatitis B and 11 with acute hepatitis B. The prevalence of the HLA-DR4 antigen was lower in the cases of chronic hepatitis B (10.5%) and C (13.6%) than in the controls (33.3%), particularly the DRB1*0401 allele (p = NS). The prevalence of HLA-DR6 was similar in chronic hepatitis B (42.1%) and acute hepatitis B (45.5%). Predominance of the DRB1*1301 and DRB1*1302 alleles were, however, observed in acute hepatitis B (36.4%) versus chronic hepatitis B (13%). These data suggest that immunologic factors such as HLA antigens may influence in the susceptibility to infection by HBV and HCV. The use of PCR techniques which discriminate between the different alleles of the HLA antigens may provide better knowledge of the immune response.

Acute Disease↗
PubMed1996

Transmission of hepatitis C virus by a cardiac surgeon.

BACKGROUND: In the course of a study conducted in 1992 through 1994 of the efficacy of screening blood donors for antibodies to hepatitis C virus (HCV), we found that two patients had acquired hepatitis C after cardiac surgery, with the transmission apparently unrelated to blood transfusions. Because their surgeon had chronic hepatitis C, we sought to determine whether he was transmitting the virus to his patients. METHODS: Of 222 of the surgeon's patients who participated in studies of post-transfusion hepatitis between 1988 and 1994, 6 contracted postoperative hepatitis C, despite the use of only seronegative blood for transfusions. All six patients had undergone valve-replacement surgery. Analyses were performed to compare nucleotide sequences encompassing the hypervariable region at the junction between the coding regions for envelope glycoproteins E1 and E2 in the surgeon, the patients, and 10 controls infected with the same HCV genotype. RESULTS: The surgeon and five of the six patients with hepatitis C unrelated to transfusion were infected with HCV genotype 3; the sixth patient had genotype 1 and was considered to have been infected from another source. Thirteen other patients of the surgeon had transfusion-associated hepatitis C and were also infected with genotype 1. The average net genetic distance between the sequences from the five patients with HCV genotype 3 and those from the surgeon was 2.1 percent (range, 1.1 to 2.5 percent; P < 0.001), as compared with an average distance of 7.6 percent (range, 6.1 to 8.3 percent) between the sequences from the patients and those from the controls. The results of phylogenetic-tree analysis indicated a common epidemiologic origin of the viruses from the surgeon and the five patients. CONCLUSIONS: Our findings provide evidence that a cardiac surgeon with chronic hepatitis C may have transmitted HCV to five of his patients during open-heart surgery.

Adult↗
PubMed1996

Chronic delta hepatitis: is the prognosis worse when associated with hepatitis C virus and human immunodeficiency virus infections?

Eighty-six patients were followed for 6.5 years to study the epidemiological, virological, and histological course of chronic delta hepatitis and the relationship of this disease with HIV and HCV infection. Patients were classified into four groups according to simultaneous HCV and/or HIV infection: group 1, HDV infection (20 cases); group 2, HDV and HCV infection (11 cases); group 3, HDV and HIV infection (12 cases), and group 4, HDV, HCV, and HIV infection (43 cases). All but 14 patients were asymptomatic at presentation. Liver histology showed chronic active hepatitis in 53 cases and cirrhosis in 19 cases. During followup, 52 patients remained asymptomatic, 34 developed hepatic dysfunction, 28 died, and 1 received a liver transplant. Among the 28 patients who died, 4 had HDV infection; 3 HDV and HCV infection; 3 HDV and HIV infection; and 18 HDV, HCV, and HIV infection. Death was due to liver failure in 16 (57%), AIDS in 10 (36%), and was unrelated to liver disease in 2 (8%) cases. There results demonstrate that chronic delta hepatitis is a severe disease, especially among drug users with HIV and HCV infection. The high morbidity and mortality of chronic delta hepatitis justifies the use of antiviral therapy to modify the natural course of the disease.

Adolescent↗
PubMed1996

Interferon vs. adenine arabinoside 5'-monophosphate in patients with anti-HBe-positive chronic hepatitis.

Anti-HBe-positive patients with precore mutants may have severe, progressive liver disease. Therapy with interferon has been effective, but relapses are frequent. To evaluate and compare two antiviral treatments, lymphoblastoid interferon (ly-IFN) and adenine arabinoside 5'-monophosphate (ARA-AMP), 20 patients with anti-HBe-positive chronic hepatitis (5 cirrhosis and 15 CAH) and viral replication (HBcAg in the liver and HBV DNA in serum) were treated. Patients were randomized into two groups: 11 patients received ARA-AMP, 5 mg/kg/day during 7 weeks, and 9 received human ly-IFN, 5,000,000 units, three times per week, during 4 months. Baseline clinical, biochemical and histological features were not significantly different between the two groups. At the end of therapy, 8 (89%) patients in the interferon group and 5 (45%) in the ARA-AMP group showed normal ALT levels and no HBV DNA in serum by a liquid hybridization assay (P < 0.05). At 1 year of follow-up, a persistent response was observed in 33% of ly-IFN patients and in 27% of ARA-AMP patients, a transient response in 56% and 18%, and nonresponse in 11% and 55%, respectively. HBV DNA remained detectable by polymerase chain reaction (PCR) in 19 of the 20 patients. Among the responders, an improvement in histological lesion and the disappearance of intrahepatic HBcAg were observed; in the nonresponders, histological lesion remained stable or worsened. In conclusion, the efficacy of interferon and ARA-AMP was similar in treating anti-HBe-positive chronic hepatitis. Although interferon treatment led to initial improvement in a larger number of patients, there was a much higher rate of relapses with this drug.

Adult↗
PubMed1996

Managing patients on interferon therapy.

Interferon (IFN) has become the standard therapy for chronic hepatitis C. The use of IFN should be accompanied by adequate diagnosis and management using standard practices as well as new and sophisticated techniques now available. A liver biopsy performed prior to IFN therapy initiation remains the standard for adequate histological diagnosis of HCV disease as well as determination of disease severity and the presence of liver cirrhosis. ALT normalization is not adequate to determine complete short-term response to IFN treatment. Adverse effects resulting from IFN therapy include a flulike syndrome, hematologic effects, neuropsychiatric effects, and thyroid abnormalities. The majority of these can be adequately managed without discontinuation of IFN treatment. However, preexisting psychiatric conditions are a contraindication to IFN therapy. IFN treatment also is contraindicated in patients with autoimmune hepatitis (AIH). Therefore, it is important to distinguish AIH from chronic HCV infection using HCV-RNA analysis and determination of autoimmune titers (including anti-LKM antibodies, anti-SMA, and ANA). Recently reported adverse effects of IFN include respiratory and ocular effects. Serological diagnosis of HCV infection has evolved to the use of second- and third-generation ELISA tests. Although sophisticated, these tests cannot distinguish between active and quiescent infection, and therefore are of limited value in monitoring treatment response. Several other techniques have been suggested: the ratio between IgG and IgM class anti-HCV core antibodies, detection of antibodies against a glycosylated recombinant product of the E2 envelope glycoprotein, and several different polymerase chain reaction (PCR) techniques. The latter appears to be the most promising. Use of these techniques should be incorporated into the monitoring of IFN therapy to assist in the evaluation of adequate treatment response, the need for treatment alteration, and estimation of relapse risk upon treatment cessation.

Alanine Transaminase↗
PubMed1996

The value of quantitative detection of HBV-DNA amplified by PCR in the study of hepatitis B infection.

BACKGROUND/AIMS: This study aimed to evaluate the usefulness of quantifying HBV-DNA amplified by polymerase chain reaction in chronic hepatitis B infection. METHODS: Serum samples were obtained from 32 asymptomatic HBV carriers and 99 chronic hepatitis B patients (62 positive for anti-HBe and 37 positive for HBeAg). In addition, serial serum samples were analyzed from 15 HBeAg positive patients undergoing antiviral therapy and 17 anti-HBe positive patients with precore mutation. HBV-DNA quantification was carried out using an enzyme immunoassay with an HBV-DNA plasma standard. RESULTS: The digoxigenin-incorporated polymerase chain reaction method detected HBV-DNA in 34.3% of the asymptomatic HBV carriers with a median HBV-DNA concentration of about 0.18 x 10(5) mol/ml (range 0.08-0.4), in 87% of the anti-HBe positive chronic hepatitis cases with a range of 0.2 to > 2 x 10(5) mol/ml and in 100% of the HBeAg positive patients, with a value in all cases over 2 x 10(5) mol/ml. We observed that after treatment, HBV-DNA tested negative in only two of the eight HBeAg positive chronic hepatitis patients who seroconverted to anti-HBe, and was positive in the seven remaining, with a median HBV-DNA value of about 0.2 x 10(5) mol/ml (0.09-0.4). In the precore mutants HBV-DNA values ranged from 0.2 to > 2 x 10(5) mol/ml. CONCLUSIONS: Polymerase chain reaction HBV-DNA quantification is a sensitive method for managing chronic hepatitis B patients, especially those with low viremia, and may be a valuable tool for evaluating the efficacy of antiviral therapy.

Adult↗
PubMed1996

[Seroepidemiology of hepatitis A virus infection in medical and nursing students. The role of vaccination].

BACKGROUND: Recent seroepidemiologic studies have demonstrated a decrease in the prevalence of hepatitis A virus infection (HAV) in relation with an improvement in hygienic conditions. The prevalence of anti-HAV in a group of health care students was studied and a vaccination program initiated in this collective. METHODS: Serum anti-HAV determination was performed by an enzymoimmunoanalysis method. A inactivated hepatitis A vaccine was administered. RESULTS: Only 18.5% of the subjects between 17-23 years-old presented anti-HAV antibodies. The prevalence of anti-HAV was related with age and the number of partners. All of the 129 immunized individuals responded to the HAV vaccine with protector antibody titles. CONCLUSION: The present study demonstrates the decrease in HAV infection among youths as well as the immunogenicity of the anti-hepatitis A vaccine.

Adolescent↗
PubMed1995

[Hepatocarcinoma and killer cell activity].

BACKGROUND: Alterations in natural killer (NK) cell activity have been described in patients with different neoplasms including hepatocellular carcinoma (HCC). Nonetheless, the relationship between this activity and the clinical situation of the patients with HCC is not well established. METHODS: A group of 33 patients with hepatic cirrhosis and non treated HCC, a group of 22 patients with only hepatic cirrhosis, and a control group of 31 healthy blood donors were studied. In all the subjects the NK cell activity was determined against the K562 cell line marked with 51Cr by the short duration cytotoxicity test, and the number of NK cells/microliters in peripheral blood was determined by flow cytometry (FACScan) using the anti-CD3, CD16 and CD56 monoclonal antibodies. RESULTS: No statistically significant differences were observed in the NK cell activity or in the number of NK cells/microliters among the three groups studied. In the patients with HCC the NK cell activity was not related to the degree of hepatic function, however the patients with tumors greater than 5 cm in diameter or multinodular tumors showed a significant decrease in NK cell activity without a decrease in the number of NK cells/microliters. CONCLUSIONS: The natural killer cell activity in patients with hepatocellular cancer is not related to subjacent hepatic cirrhosis but is related to tumor size.

Aged↗