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Biomedical subjects

M Buti

Publications and source records attributed to M Buti.

At least 55 records · Page 3Linked to original sources
PubMed1994

Etiology of acute sporadic hepatitis in Spain: the role of hepatitis C and E viruses.

The aim of this study was to determine the prevalence of hepatitis viruses and analyze the epidemiological features in acute hepatitis in Spain. Consecutive serum samples from 341 patients with acute hepatitis were tested for IgM anti-hepatitis A virus, IgM anti-hepatitis B core antigen and HBsAg. The antibody to hepatitis C virus was determined using a second-generation enzyme immunoassay. In selected cases, serum was tested for antibodies for hepatitis E virus by enzyme immunoassay and hepatitis C virus-RNA by polymerase chain reaction. One hundred and fourteen (33.2%) cases of acute hepatitis were due to hepatitis A virus, 68 (20%) to hepatitis B virus, 21 (6%) to hepatitis D virus and 74 (21.8%) to hepatitis C virus infection. Of the 74 hepatitis C virus infections, 48 (65%) were anti-HCV positive at the time of diagnosis, while 26 (35%) seroconverted to anti-HCV later during follow-up. No case of hepatitis E virus infection was detected. The remaining 64 cases were negative to all acute serological markers and were classified as non-A, non-B, non-C, non-E hepatitis. Hepatitis C virus was implicated in 65/119 (54.6%) of the cases among intravenous drug users but in only in 9/199 (4.5%) of the sporadic cases (p < 0.01). Progression to chronic hepatitis was observed more frequently in anti-hepatitis C virus-positive than in antibody-negative-cases (42/70; 60% vs. 3/52 or 5.5%) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

Detection of hepatitis B precore mutants by the fluorescent linear polymerase chain reaction sequencing method.

To evaluate the presence of precore mutants, serum samples from 25 patients with chronic hepatitis B, HBV-DNA positive (5 HBeAg and 20 anti-HBe positive) were studied. The complete precore-core region of HBV-DNA was directly sequenced after polymerase chain reaction amplification by a fluorescent linear polymerase chain reaction sequencing method. Precore variants were detected in one HBeAg positive and in all 20 anti-HBe positive patients: in 19 cases, G to A at position 1896, with or without the substitution G to A at position 1899, in two cases C to T substitution at position 1817 which also produces a stop codon (CAA to TAA), one accompanied by the mutation G to A at position 1896. The only mutation observed in the patient who was initially HBeAg positive patient was a G to A substitution at position 1899. Consecutive serum samples from a patient with chronic hepatitis B, initially had the simultaneous presence of wild type and variant strains. Elimination of the wild-type strain was associated with reactivation of liver disease. Analysis of the sequences obtained demonstrated the heterogeneity of the hepatitis B virus genome in the precore-core region. These results indicate that the main cause of non-expression of HBeAg in chronic hepatitis B in our country is the substitution of G to A at nucleotide 1896, alone or accompanied by other variants. Fluorescent linear polymerase chain reaction is a fast and sensitive method to study heterogeneity in the precore-core region.

Amino Acid Sequence↗
PubMed1994

Synthesis of a non-radioactive hepatitis B virus DNA probe from human serum by the polymerase chain reaction.

A method for synthesizing probes for detecting hepatitis B virus DNA in serum was developed. It uses DNA extracted from the serum of an hepatitis B virus carrier as target, and digoxigenin-11-dUTP incorporated in DNA sequences during the polymerase chain reaction as tracer. Using a spot hybridization assay, the sensitivity and specificity of the digoxigenin-labelled DNA probe were compared with two standard hepatitis B virus DNA probes, synthesized with cloned hepatitis B virus DNA and labelled either with digoxigenin or 32P by random priming. Data obtained from the three methods showed an excellent correlation. Thus, hepatitis B virus DNA extracted from human serum and labelled by polymerase chain reaction may be considered a suitable alternative to cloned DNA. It provides reliable probes and eliminates the need for facilities and personnel dedicated to the manipulation of clones. These advantages will allow a wider application of hepatitis B virus DNA testing in clinical practice.

Base Sequence↗
PubMed1993

Detection of hepatitis delta virus RNA in human liver tissue by non-radioactive in situ hybridization.

Several studies have demonstrated the presence of serum HDV-RNA by molecular hybridization in patients with chronic D infection, but there is scarce information about the presence of HDV-RNA in hepatic tissue. The presence of HDV-RNA by in situ hybridization (ISH) with a non-radioactive probe in paraffin-embedded hepatic tissue was studied in 29 patients with chronic delta hepatitis (20 with and 9 without intrahepatic delta antigen) and correlate their presence with the expression of hepatic delta antigen and serum HDV-RNA by dot-blot hybridization. HDV-RNA was detected by in situ hybridization in 18 cases: 16 of the 20 (80%) biopsies with intrahepatic delta antigen and 2 of the 9 (22%) without. HDV-RNA was not detected in any of the control cases. Serum HDV-RNA was found in 19 cases: 18 (90%) of 20 chronic delta hepatitis cases with tissular delta antigen and one of the 9 without intrahepatic delta antigen. All patients except one, who was positive for intrahepatic HDV-RNA, showed serum HDV-RNA. However, in two cases ISH detected hepatic HDV-RNA without tissular HDAg; one of these also had serum HDV-RNA and in the other positivity for hepatic HDV-RNA by ISH was the only marker of viral delta replication. In conclusion, detection of HDV-RNA in hepatic tissue by in situ hybridization with a digoxygenin-labelled probe is a rapid and sensitive method that could be a useful tool for diagnosis of HDV infection in clinical laboratories.

DNA Probes↗
PubMed1993

Disappearance of serum hepatitis B virus DNA by polymerase chain reaction after adenine arabinoside 5'-monophosphate therapy in chronic hepatitis B.

The aim of antiviral therapy in chronic hepatitis B is the cessation of viral replication, which may be demonstrated by the loss of hepatitis B "e" antigen (HBeAg) and serum hepatitis B virus DNA (HBV-DNA) detected by dot-blot hybridization. With the development of the sensitive polymerase chain reaction (PCR) technique for detecting HBV-DNA, it has become apparent that many HBeAg negative patients may still have small amounts of circulating viral DNA. We assessed 19 of 25 patients with chronic hepatitis B who seroconverted from HBeAg to anti-HBe after adenine arabinoside 5'-monophosphate therapy (5 mg.kg-1.day-1 for 7 weeks) to determine whether serum HBV-DNA became undetectable. Sixteen of the 19 HBeAg negative patients remained hepatitis B surface antigen (HBsAg) positive, and the other three lost HBsAg during follow-up. All of them were HBV-DNA negative by dot-blot hybridization. Using the PCR technique, HBV-DNA became negative in 13 (81.2%) of the 16 patients who seroconverted to anti-HBe without losing HBsAg, and in all the patients who lost HBsAg. These data suggest that the majority of patients who respond to adenine arabinoside 5'-monophosphate show a complete inhibition of hepatitis B virus replication, as demonstrated by the absence of viral DNA by PCR. This inhibition was present in all patients who, at the same time, lost HBsAg.

Adult↗
PubMed1992

Evaluation of anti-HCV positive blood donors identified during routine screening.

Of 30,231 donors tested, 368 (1.2%) were anti-HCV positive. Of these, 254 have been evaluated, with the following results: only 25% have a history of parenteral risk, seroprevalence increases with age and approximately 80% of those that are anti-HCV positive in our population are probably infected with HCV. In addition, an unexpectedly large number of these persons have chronic and/or severe liver disease and will require combined diagnostic approaches for accurate evaluation.

Age Factors↗
PubMed1992

Long-term immunogenicity and efficacy of hepatitis B vaccine in hemodialysis patients.

Although the efficacy of hepatitis B vaccines in patients under chronic hemodialysis treatment has been well documented, the persistence of immunity in this population remains largely unknown. In this study we have followed 60 hemodialysis patients up to 3 years after primary hepatitis B vaccination (four doses of recombinant hepatitis B vaccine; Engerix B, 20 mg/dose) to evaluate the persistence of immunity (as indicated by serum levels of antibody to hepatitis B surface antigen-anti-HBs-higher than or equal to 10 mIU/ml). Fourty-four (73%) patients developed anti-HBs levels above 10 mIU/ml after vaccination; the remaining 16 (27%) vaccinees were considered nonresponders and were given a booster dose that again failed to elicit an immunoresponse. After 3 years of follow-up, 18 out of 44 (41%) responders had no detectable anti-HBs levels in the serum (antibody loss occurring within 8 and 12 months in 3 cases, within 1 and 2 years in 13, and within 2 and 3 years in 2 other cases). When compared with the responders that lost their antibodies during the follow-up period, those who remained immunoreactive 3 years after vaccination was initiated were younger and had higher anti-HBs levels at 8 months of follow-up. Two hepatitis B virus infections were detected among nonresponders during the follow-up period. Based on these data, we conclude that patients undergoing chronic hemodialysis therapy not only have lower response rates to hepatitis B vaccination than healthy adults, but also that these are frequently transient.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1991

Clinical significance of two forms of IgM antibody to hepatitis delta virus.

Separation of 7-8 S and 19 S forms of serum IgM antibodies to the hepatitis delta virus by rate-zonal centrifugation was carried out on serum from 24 patients with hepatitis delta virus infection: 4 patients with acute, self-limited hepatitis; 5 patients with hepatitis delta virus superinfection progressing to chronicity; and 15 patients with chronic hepatitis delta virus. The high molecular weight IgM form (19 S) was predominantly detected in acute hepatitis delta virus cases, whereas the low molecular weight (7 S) form was found in chronic hepatitis delta virus cases. The serological profile of these two forms of IgM antibody to hepatitis delta virus was investigated in serial samples from five patients with acute hepatitis delta virus superinfection that evolved to chronic hepatitis delta virus. We found that, in the acute stage of the disease, the 19 S form was predominant, whereas 6 mo later a predominance of 7-8 S IgM was observed. These results suggest that IgM antibody to hepatitis delta virus antibody forms are different in acute and chronic hepatitis delta virus infection and that their detection only helps in differentiating an acute infection from a chronic infection but not a hepatitis delta virus-hepatitis B virus-HBV coinfection from hepatitis delta virus superinfection in the acute stage of the disease.

Acute Disease↗
PubMed1991

Influence of human immunodeficiency virus infection on cell-mediated immunity in chronic D hepatitis.

To determine whether the abnormalities of cell-mediated immunity described in chronic D hepatitis are associated with hepatitis D virus (HDV) infection or concomitant human immunodeficiency virus (HIV) infection, serologic and tissue hepatitis B virus (HBV) and HDV markers and T lymphocyte subsets were studied in serum samples from 38 patients with chronic D hepatitis, 26 of whom had HIV infection. Patients with chronic D hepatitis and HIV infection had significantly lower peripheral blood T4:T8 ratios resulting from a significant increase in T8+ (suppressor/cytotoxic) cells, while numbers of T lymphocyte subsets were normal in cases with chronic D hepatitis only. HIV+ patients showed an increase in HBV replication (identified by hepatitis B core antigen in liver and hepatitis B e antigen and HBV DNA in serum) and in HDV replication (tissue D antigen and HDV RNA) without evidence of more active liver disease. Probably the immunologic disturbances detected in chronic D hepatitis are secondary to HIV infection, do not contribute to the pathogenesis of liver injury, and are associated with increased viral B and D replication.

Adolescent↗
PubMed1991

Digoxygenin-labelled DNA-probe: a rapid non-radioactive method for hepatitis B virus DNA detection in serum.

The sensitivity and specificity of two non-radioactive spot hybridization assays for hepatitis B virus DNA (HBV-DNA) using biotin and digoxygenin-labelled DNA probes were investigated in parallel in 122 serum samples from patients with chronic hepatitis B and 50 controls. The results were compared with an isotopic technique using a 32P-labelled probe. HBV-DNA was detected in 56 (80%) out of 70 hepatitis B "e" antigen (HBeAg)-positive cases and in 4 (8%) out of 52 antibody to hepatitis B "e" antigen (anti-HBe)-positive cases using the digoxygenin or 32P-labelled probes. No false positives were found with either method. Using the biotin-labelled probe, 16% of sera gave discordant results, which were considered to be false positive. The time required for detection of serum HBV-DNA was 2 hours for the non-radioactive probes and 16 hours for the isotopic probes. This study suggests that the digoxygenin-labelled probe for detection of HBV-DNA is the most rapid and sensitive method for routine diagnosis of viral replication in clinical laboratories.

Alanine Transaminase↗
PubMed1990

[A study of 158 cases of acute delta hepatitis].

We have prospectively studied 158 cases of acute hepatitis delta observed during the last 7 years in a general hospital. Among them 136 were male and 22 female. The mean age was 22.7 years with a range between 16 and 61 years. The epidemiologic factors were drug addiction by parenteral route in 145 cases (92%), sexual transmission in 5 (3%), post transfusional in 2 (1%) and unknown in 6 (4%). With respect to the delta type infection, 105 cases (66%) were coinfections with type B and delta, and 53 patients had a type delta superinfection (34%). The clinical course was a fulminant hepatitis in three cases (two cases of coinfection B and delta an one case of delta superinfection), and an acute benign hepatitis in 155 patients. The follow-up of 118 patients revealed that 96% of coinfections by type B and delta evolved to the chronicity showing findings of active chronic hepatitis or hepatic cirrhosis. It should be noted that in 4 cases of superinfection delta type (11%) the HBsAg was negative after several months of positivity. In these patients the level of transaminases normalized and the hepatic histology evidenced alterations of chronic active hepatitis (2 cases) and hepatic cirrhosis (2 cases) without identification of tissular delta antigen.

Acute Disease↗