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Biomedical subjects

R Esteban

Publications and source records attributed to R Esteban.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1995

Yeast viral 20 S RNA is associated with its cognate RNA-dependent RNA polymerase.

Most Saccharomyces cerevisiae strains carry in their cytoplasm 20 S RNA, a linear single-stranded RNA molecule of 2.5 kilobases in size. 20 S RNA copy number is greatly induced in stress conditions such as starvation, with up to 100,000 copies per cell. 20 S RNA has coding capacity for a protein of 91 kDa (p91) with sequences diagnostic of RNA-dependent RNA polymerases of (+) strand and double-stranded RNA viruses. We detected p91 in 20 S RNA-carrying strains with specific antisera. The amount of p91 in growing cells is higher than that of stationary cells and similar to the one in 20 S RNA-induced cells. Although 20 S RNA is not encapsidated into viral particles, p91 non-covalently forms a ribonucleoprotein complex with 20 S RNA. This suggests a role of p91 in the RNA to RNA synthesis processes required for 20 S RNA replication. Although the strain analyzed also harbors 23 S RNA, a closely related single-stranded RNA, 23 S RNA is not associated with p91 but with its putative RNA polymerase, p104. Similarly, 20 S RNA is not associated with p104 but with p91. These results suggest that 20 S RNA and 23 S RNA replicate independently using their respective cognate RNA polymerases.

Fungal Proteins↗
PubMed1995

Hepatitis B virus infection: precore mutants and its relation to viral genotypes and core mutations.

The precore-core gene of hepatitis B virus (HBV) was directly sequenced from serum samples of 42 patients with chronic B hepatitis (19 hepatitis B e antigen [HBeAg]+ and 23 anti-HBE+). Viral genotypes were determined by comparison with 11 reference sequences and by restriction analysis. Genotype A was identified in 16 cases, genotype D in 24 cases, and other genotypes in 2 cases. Precore mutations, mainly M1 (stop at codon 28), were differently distributed among the viral genotypes: 3 cases (18.8%) with genotype A and 18 cases (75%) with genotype D. In sequences with precore mutants, the encapsidation signal was more stable (negative stabilization energy) than in sequences without precore mutants. In genotype A, the M1 mutation coexisted with a second mutation (C-->T at position 1858 in codon 15), and both mutations were paired in the secondary structure of the RNA encapsidation signal, which justified the rare presence of precore mutants in this genotype. The analysis showed different distribution of mutations depending on the viral genotype; patients with genotype D were more likely to have persistent HBV infection by selection of precore mutants. Multiple amino acid substitutions were detected in the core region, mainly in two subsequences that have been previously described as epitopes (flanked by codons 11 to 27 and 74 to 83); the presence of these mutations was significantly related to the presence of precore variants which abolished the expression of HBeAg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Hepatitis E virus infection in acute hepatitis in Spain.

In order to study the prevalence of hepatitis E virus (HEV) infection in developed countries, IgG and IgM anti-HEV were determined in serum samples from 382 patients with acute viral hepatitis (244 hepatitis A, 48 hepatitis B and/or D, and 90 non-A, non-B, non-C hepatitis), 76 healthy subjects, 55 hemophiliacs and 50 patients on hemodialysis. IgG anti-HEV antibodies were detected and confirmed by a synthetic peptide-based EIA in 5 (5.6%) non-A, non-B, non-C acute hepatitis, in 3 (6.5%) B and D acute hepatitis, in 10 (4%) acute A hepatitis, in 3 (5.5%) of 54 healthy adults in none of the hemophiliacs and in 3 (6%) patients on hemodialysis. IgM anti-HEV antibodies were only detected in two cases of acute hepatitis B and/or D. Analysis of serial serum samples demonstrated IgG anti-HEV seroconversion in 3 of the 18 confirmed cases; one of them was also positive for IgM anti-HEV. All 3 acute anti-HEV-positive hepatitis cases occurred in adults, were community-acquired (two of them were intravenous drug addicts) and had a self-limited course. These results demonstrate that HEV is a minor cause of acute hepatitis in Spain. A similar low rate of IgG anti-HEV antibodies was detected in patients with different diseases, suggesting that HEV has a very low epidemiological impact. An apparent association of HEV infection with hepatitis B and D suggests a possible parenteral transmission of a mainly enteral pathogen.

Acute Disease↗
PubMed1995

Hepatitis C virus infection in renal transplant recipients: epidemiology, clinical impact, serological confirmation and viral replication.

The presence and significance of hepatitis C virus infection was evaluated in 241 renal transplant recipients from our hospital. Hepatitis C virus antibodies were tested by second-generation enzyme immunoassay, followed by second- and third-generation immunoblot assays (RIBA-2 and RIBA-3); hepatitis C virus RNA was measured by nested polymerase chain reaction. Hepatitis C virus antibodies, which were detected in 46.5% of patients, were mainly present before transplantation and independently associated with the total amount of transfused blood, time in hemodialysis and duration of posttransplant follow up. Liver dysfunction (alanine aminotransferase elevation) was observed in 50% of antibody-positive recipients, and 92.5% of patients with chronic liver disease without hepatitis B infection were infected with hepatitis C virus. Most antibody-positive patients (78.4%) tested positive by RIBA-2, but 21.6% were indeterminate; RIBA-3 was positive in 90% of these indeterminates. Hepatitis C virus RNA detection was positive in 96% of antibody-positive cases tested, in 20% of patients who were already anti-HCV negative before transplantation and also demonstrated persistence of HCV infection in all cases who, being antibody positive prior to transplantation, lost these antibodies during follow up (9% of transplanted patients). In conclusion, hepatitis C virus infection is extremely prevalent in renal transplant recipients from Spain and is the main cause of chronic liver disease in these patients. Confirmation by supplemental assays of anti-HCV antibodies is not necessary, but hepatitis C virus RNA testing is indispensable to detect those cases who lose or do not develop hepatitis C virus antibodies.

Adult↗
PubMed1995

Risk of hepatitis B in infancy and childhood.

Hepatitis B virus (HBV) may be transmitted from mother to child during delivery or in the neonatal period (vertical transmission) or by direct person to person contact in teenagers and adults (horizontal transmission). Patients infected horizontally, as occurs in countries with a low prevalence of infection, achieve complete resolution in up to 95% of cases and acquire permanent immunity. On the other hand, 95% of infected newborns cannot clear the virus and remain chronic carriers. The relevance of this method of infection in newborns is twofold. First, because of persistent infection throughout life, they are at risk of developing liver cirrhosis and hepatocellular carcinoma. Second, they are permanent reservoirs of hepatitis B infection, facilitating its spread. Even in countries with low or intermediate prevalence, the importance of vertical transmission is manifest. In a study carried out in our hospital before screening of pregnant women for hepatitis B surface antigen (HBsAg) was implemented, the prevalence of HBsAg carriers among 8200 pregnant women was 1.24%, 6% of whom were HBeAg positive, for a minimum rate of transmission of HBV of 6%. From these data, there will be at least 65 children per year in Catalonia who become chronic carriers and about 1000 children at risk of acquiring HBV infection. Epidemiological studies carried out in Catalonia confirmed our results. Among children under 10 years of age in whom vertical transmission was likely, 1.7% had serum markers of HBV infection and 0.2% were HBsAg positive. These data confirm the need for universal HBV prevention in newborns, in addition to any other programme carried out in teenagers or adults.

Adult↗