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Biomedical subjects

M R Brunetto

Publications and source records attributed to M R Brunetto.

At least 55 records · Page 3Linked to original sources
PubMed1996

Adenine arabinoside monophosphate coupled to lactosaminated human albumin administered for 4 weeks in patients with chronic type B hepatitis decreased viremia without producing significant side effects.

A conjugate of adenine arabinoside monophosphate (ara-AMP) with the liver-targeting molecule lactosaminated human serum albumin (L-HSA) was administered by intravenous infusion for 28 days to eight patients with chronic type B hepatitis. The daily dose varied among the patients, ranging from 34 mg/kg to 53 mg/kg (equal to 1.5 and 2.3 mg/kg ara-AMP, respectively). Pharmacokinetic analysis indicated that, at every dose tested, the conjugate was disposed of without accumulation. Viral DNA serum levels fell markedly during treatment; values rose again when treatment was ceased. The L-HSA-ara-AMP conjugate did not cause either the neurotoxic side effects of free ara-AMP or other adverse clinical reactions. It produced a significant increase both in serum alkaline phosphatase activity and platelet number, and a small but significant decrease in erythrocyte number. These laboratory parameters returned to normal levels within 2 months after treatment. The conjugate induced the production of small amounts of antibodies (approximately 20 pmol of conjugate bound by 1 mL of serum) in one patient only. In conclusion, the present results indicate that the L-HSA-ara-AMP conjugate can exert the antiviral activity of ara-AMP in chronic type B hepatitis patients without producing the neurotoxic side effects which hamper a 4-week period of treatment with the free drug.

Adult↗
PubMed1996

A factorial design to determine the effects of some variables in the long-term stability of methylmercury standard solutions in water.

A factorial composite design has been employed for a rapid exploration of the effect of some parameters on the stability of spiked methylmercury iodide solutions. The analysis has been performed by capillary gas chromatography with electron-capture detection. The results obtained by the factorial and the univariate methods are in a good agreement. Although, the factorial design does not allow a discrimination of the significance among the same kind of factors, it greatly reduces the number of experiments when the different variables are investigated.

Journal Article↗
PubMed1996

Quantitative analysis of IgM anti-HBc in chronic hepatitis B patients using a new "gray-zone" for the evaluation of "borderline" values.

BACKGROUND/METHODS: In order to define the clinical significance of borderline levels of IgM anti-HBc in chronic hepatitis B patients, we followed up 89 untreated hepatitis B patients (19 HBeAg pos and 70 anti-HBe pos) for 1 year, with monthly monitoring of IgM anti-HBc using a highly sensitive quantitative microparticle enzyme immunoassay (IMx CORE-M, Abbott). As a control group we used 304 healthy subjects: 150 HBsAg negative and anti-HBc/anti-HBs positive, and 154 without markers of HBV infection. The statistical analysis performed by Receiver Operating Characteristic curve indicated the 100% sensitivity cut-off at 0.081 IMx index and 100% specificity cut-off at 0.358 IMx index. RESULTS: We could define the range of a chronic hepatitis B "gray-zone" between 0.100 [80.6% specificity (95% CI, 76.2%-85%), 96.6% sensitivity (95% CI, 92.8%-100%)] and 0.200 [95.7% specificity (95% CI, 93.4%-98%) and 78.7% sensitivity (95% CI, 70.2%-87.2%)] of the IgM anti-HBc-IMx index. In fact, none of the chronic hepatitis B patients had IgM anti-HBc-IMx values persistently below 0.100 during the follow-up, whereas 57.3% had values persistently higher than 0.200. In 38.2%, IgM anti-HBc values occasionally fell within the "gray-zone" limits. In the remaining four patients (4.4%), the results overlapped the "gray-zone" values. CONCLUSIONS: These results suggest that the use of a chronic hepatitis B "gray-zone" for values of quantitative IgM anti-HBc assays helps to distinguish "true healthy carriers" from asymptomatic chronic anti-HBe positive hepatitis B patients who have been shown to have temporary remissions of liver disease and frequently undetectable serum HBV-DNA.

Adolescent↗
PubMed1996

High prevalence of autoimmune phenomena in hepatitis C virus antibody positive patients with lymphoproliferative and connective tissue disorders.

The aim of this study was to investigate whether hepatitis C virus (HCV) may perturb the immune system towards autoreactivity. We studied the relationship between the prevalence of anti-HCV and the presence of laboratory and/or clinical autoimmune features in 300 patients: lymphoid malignancies (167) and autoimmune disorders (connective tissue diseases 100; idiopathic thrombocytopenic purpura (ITP) 33). As a control, hepatitis B surface antigen (HBV) and anti-hepatitis B core antigen (anti-HBc) were related to the same parameters. Anti-HCV and anti-HBV were detected in 68/300 (22.6%) and 70/300 (24.6%) patients, respectively. HCV prevalence was 18% in lymphoproliferative disorders (anti-HBc 28.1%) and 26% in connective tissue disease (anti-HBc 16.3%). Among ITP cases, 12/33 (36.4%) were anti-HCV+ and 10/33 (30.3%) anti-HBc+. In 24/30 (80%) anti-HCV+ patients with lymphoproliferative disorders at least one serologic or clinical autoimmune abnormality was detected. To the contrary, only 10/45 (22.2%) anti-HBc+ patients with lymphoproliferative disorders had at least one serologic or clinical abnormality (P < 0.0001). A statistically significant correlation was observed between HCV prevalence and the number of autoimmune alterations in both lymphoproliferative and connective tissue disorders, which was not found for anti-HBc. These data suggest that HCV may skew the immune system toward the production of autoantibodies and also support the possibility that some cases of ITP may be linked to both HCV and HBV infection.

Adolescent↗
PubMed1996

Hepatitis G virus RNA in the serum of patients with elevated gamma glutamyl transpeptidase and alkaline phosphatase: a specific liver disease? [corrected].

We tested the sera of 67 consecutive patients for hepatitis G virus (HGV) RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). These patients (42 males and 25 females, median age 35 years, range 13-64 years) had liver disease of unknown aetiology and were without markers of hepatitis (A-E) viruses or signs of genetically determined, autoimmune, alcoholic or drug-induced liver disease. The controls in this study were 110 patients (50 females and 60 males, median age 45 years, range 9-65 years) with chronic hepatitis B virus (HBV) infection (19 patients) or hepatitis C virus (HCV) infection (91 patients). Ten of 67 (14.9%) patients with cryptogenic disease were positive for HGV RNA by at least three separate tests; HGV RNA was also detected in one of 19 (5.3%) hepatitis B surface antigen (HBsAg) carriers and in nine of 91 (16.6%) patients with antibody to HCV. These data suggest that HGV occurs as frequently in HCV-infected patients as in those with cryptogenic disease. Elevated serum gamma glutamyl transpeptidase (gamma-GT) (higher than twice the normal value) and alkaline phosphatase levels were found in eight of 10 (80%) HGV RNA positive patients and in six of 57 (10.5%) HGV RNA negative patients (P < 0.0001). Five (50%) HGV RNA positive patients had non-specific inflammatory bile duct lesions. A statistically significant difference was observed between HGV RNA positive and negative patients with chronic HBV or HCV infections (P < 0.029). Therefore, the spectrum of liver disease associated with HGV is wide, but a characteristic lesion of the bile duct leading to elevation of cholestatic enzymes might be specific for this virus.

Adolescent↗
PubMed1996

Risk of HBV reinfection after liver transplantation in HBsAg-positive cirrhosis. Primary hepatocellular carcinoma is not a predictor for HBV recurrence. The European Cooperative Study Group on Liver Cancer and Transplantation.

Two hundred and twenty-eight patients who underwent orthotopic liver transplantation for hepatitis B-related cirrhosis in 11 European Liver Transplant Centers were collected. The male/female ratio was 184/44, with a median age of 41 years (13-66). In 55 patients (24%) hepatocellular carcinoma was associated with liver disease. All cases were stratified for pre-orthotopic liver transplantation viral characteristics: HBV-DNA neg/HBeAg neg: 106 patients (47%), HBV-DNA neg/Delta pos: 80 (35.5%), HBV-DNA pos/HBeAg pos: 28 (12.5%), other 14 (5%). In 49 patients (21.4%) post-orthotopic liver transplantation passive prophylaxis with anti-HBs immunoglobulins was not followed, while in 179 patients the anti-HBs serum titer was kept above 100-200 mU/ml. Overall 5-year actuarial survival of the series was 54%. One hundred and eighty-five patients were evaluable for HBsAg reappearance in the serum at various intervals after orthotopic liver transplantation. Overall 3-year HBV-free survival of these patients was 55%. There was a significant difference in 3-year HBV-free survival between HBV-DNA neg (52%), HBV-DNA pos (13%) and Delta pos (73%) patients (p: 0.03). Sixty-three percent of patients in the prophylaxis group were HBV-free, compared to only 25% of untreated patients (p < 0.001). Three-year HBV-free survival in patients with or without HCC was 44% and 59%, respectively. Cox-multivariate analysis revealed that only post-transplantation prophylaxis (p: 0.003) and pre-transplantation viral activity (p: 0.004) can be considered as independent factors affecting HBV recurrence. Candidates with hepatocellular carcinoma in HBV-cirrhosis should not be excluded from orthotopic liver transplantation, supporting the idea of a higher risk of post-transplantation viral reactivation.

Adolescent↗
PubMed1996

[Is HCV RNA detectable in the ultrafiltrate?].

We investigated by molecular biology the possibility that the HC virus passes by the dialysis membranes into the ultrafiltrate, making the HD monitor a way of HCV transmission. HCV-RNA was tested in blood and in UF samples during 2 HD sessions at T-0, 30, 60, 120 min and at HD end. HCV-RNA was measured by RT-PCR. Viraemia in patients was > 10(-4) gen Eq/ml and remained unchanged along HD, HCV-RNA was not found in whole UF and its x100 concentrates during the HD. We failed to prove the passage of the HCV into the UF, at least in standard conditions.

Hemofiltration↗
PubMed1996

Variations in the hypervariable region 1 of the envelope region E2 of hepatitis C virus RNA appear associated with virus persistence independently of liver disease.

The high genetic variability of the 5' end of the envelope protein-coding region E2 (HVR1 E2) of Hepatitis C Virus (HCV) RNA has been suggested by many authors to play an important role in both virus persistence and outcome of liver disease. We studied the relations between HVR1 E2 variability and HCV genotypes, HCV-RNA levels and liver disease in 8 chronic HCV carriers (5 males and 3 females, median age 41 years, followed-up for a mean period of 3 years). Four were healthy HCV carriers with persistently normal ALT levels and normal liver histology and 4 patients with chronic liver disease. In each patient, the HVR1 E2 variability of 2 serum HCV-RNA isolates obtained at least 12 months apart were evaluated by direct sequencing. Nucleotide and amino acid homologies ranged between 97.6%-57.1% and 92.8%-25% in healthy carriers and 95.2%-55.9% and 89.3%-32.1% in patients, respectively. We did not observe any correlation between HVR1 E2 heterogeneity and HCV genotypes, viraemia levels, presence and extent of liver necroinflammation. Our findings suggest that HVR1 E2 heterogeneity has no direct implications in hepatitis, pathogenesis but it could play a major role in virus persistence.

Adult↗
PubMed1995

Selective determination of antimony(III) and antimony(V) in liver tissue by microwave-assisted mineralization and hydride generation atomic absorption spectrometry.

Antimony(III) and antimony(V) species have been selectively determined in liver tissues by optimizing the acidic conditions for the evolution of stibine using the reduction with sodium borohydride. The results show that a response for Sb(III) of 0.5 to 20 microg l(-1) was selectively obtained from samples in a 1 mol l(-1) acetic acid medium. The best response for total antimony from 1 to 20 microg l(-1) is obtained after sample treatment with a 0.5 mol l(-1) sulfuric acid and 10% w/v potassium iodide. Microwave digestion has been necessary to release quantitatively antimony species from sample slurries. The amount of Sb(V) was calculated from the difference between the value for total antimony and Sb(III) concentrations. A relative standard deviation from 2.9 to 3.1% and a detection limit of 0.15 and 0.10 microg l(-1) for Sb(III) and total Sb has been obtained. The average accuracy exceeded 95% in all cases comparing the results obtained from recovery studies, electrothermal atomic absorption spectrometry and the analysis of certified reference materials.

Journal Article↗
PubMed1995

Effect of surfactants and of ultrasonic mixing in the determination of calcium, magnesium, copper and zinc in whole blood by flow injection flame atomic absorption spectrometry.

The behaviour of five non-ionic surfactants of different chain lengths was studied in relation to the improvement in sensitivity that their use affords as a sample pre-treatment procedure for the determination of calcium, magnesium, copper and zinc in real samples by flow injection flame atomic absorption spectrometry. The results show that the sensitivity changed with surfactant concentration, length of the hydrophobic chain and ultrasonic agitation time. Higher outputs were obtained with Triton X-100, which is the surfactant with the shortest chain length. In this case, the sensitivity of the atomic absorption signal increased 2.2, 2.2, 2.3 and 2.5-fold for aqueous solutions of calcium, magnesium, copper and zinc, respectively. The data also showed that ultrasonic agitation of the sample probe considerably improved the sensitivity, regardless of the element under evaluation. A relative precision between 0.6 and 3.3% was achieved with a smaller sample consumption than by the conventional atomic absorption method. The results obtained from the proposed sample pre-treatment procedure for the analysis of the elements under study were in good agreement with those obtained by microwave-assisted mineralization and flow injection AAS (for zinc and copper) and flame AAS (for calcium and magnesium).

Adult↗
PubMed1995

Gastric tissue selenium levels in healthy persons, cancer and non-cancer patients with different kinds of mucosal damage.

The gastric tissue levels of selenium (Se) were examined in 15 healthy subjects aged 18-43 (mean 36 +/- 12) years, 17 patients with stomach cancer aged 23-79 (mean 60 +/- 17) years, 20 patients with mild gastritis aged 18-65 (mean 35 +/- 12) years, 13 patients with chronic gastritis aged 28-69 (mean 47 +/- 15) years, 33 patients with erosive gastritis aged 16-70 (mean 49 +/- 17) years and 23 patients with ulcers aged 22-76 (mean 49 +/- 17) years. The Se concentration was determined by electrothermal atomic absorption spectrometry (ETAAS) with palladium as a matrix modifier. The mean +/- the standard deviation (SD) of the gastric tissue Se levels were 473 +/- 80, 36 +/- 9.0, 355 +/- 243, 567 +/- 246, 571 +/- 241 and 813 +/- 427 micrograms/Kg in healthy subjects and in patients with cancer, ulcers, mild gastritis, chronic gastritis and erosive gastritis, respectively. The Se concentration in the biopsies of patients with gastric ulceration and cancer were significantly lower than that in patients with gastritis (p < 0.05) and the other conditions (p < 0.0001).

Adolescent↗
PubMed1995

The fluctuations of hepatitis C virus RNA and IgM anti-HCV (core) serum levels correlate with those of alanine aminotransferases during the hepatitis relapses of patients treated with interferon.

Variations in the serum levels of hepatitis C virus (HCV) RNA. IgM antibody against the HCV 'core' structural protein (c22) and alanine amino-transferase (ALT) were measured in 23 patients with chronic hepatitis C who underwent therapy with interferon-alpha 2a (IFN alpha 2a). Low pretreatment levels of viraemia and undetectable IgM anti-core were significantly associated with a long-term response to treatment. In patients with hepatitis relapses after the end of treatment, HCV RNA levels increased before or at the same time as ALT in 29 out of 34 cases (85%). ALT flares occurred before or simultaneously with IgM anti-core elevations in 18 out of 20 cases (90%). Therefore, post-treatment hepatitis C exacerbations show the same sequence of events seen as in hepatitis B exacerbations (increases of viraemia followed by those of ALT and IgM anti-'core'). These findings underscore the diagnostic and prognostic usefulness of monitoring anti-HCV-positive patients with quantitative assays for HCV markers.

Alanine Transaminase↗
PubMed1995

Treatment of chronic anti-HBe-positive hepatitis B with interferon-alpha.

We studied the prevalence of long-term responders to interferon-alpha (IFN-alpha) treatment (undetectable levels of serum IgM anti-HBc, HBV-DNA and normal ALT values for 3 years) in 53 anti-HBe-positive chronic hepatitis B patients. Forty-two of them were treated with (6-18 MU) alpha-2a-recombinant-IFN t.w. for 4-6 months, and the remaining 11 with 10 MU of lymphoblastoid-IFN thrice weekly for 6 months. At the end of treatment, HBV-DNA levels were undetectable and ALT values within the normal range in 34 of 53 patients (60%); IgM anti-HBc levels decreased in all the 34 patients, falling below 10 PEI U in 2/34 (6%). Response to treatment was maintained throughout the follow-up (mean 3 years, range 2-7 years) in five patients (9.4%). The remaining 29 patients experienced HBV reactivation within median follow-up of 6 months (range 1-22 months; 90% of cases within 12 months). Overall 4/9 long-term responders (44.4%) cleared serum HBsAg. In conclusion, chronic anti-HBe-positive hepatitis B has a lower IFN treatment response rate than the HBeAg-positive form; however, among long-term responders, the incidence of serum HBsAg clearance is comparable in the two forms. Because of the high rate of relapses, stringent monitoring criteria (HBV-DNA, IgM anti-HBc and ALT monthly tested for at least 12 months) are mandatory.

Adolescent↗
PubMed1995

Hepatocellular carcinoma and infections with multiple hepatitis viruses.

Hepatitis B virus (HBV) plays a major role in liver carcinogenesis. HBV-DNA integration into cellular DNA provides some molecular basis for understanding the mechanisms of neoplastic transformation of the liver cell. Persistence of HBV-DNA episomic forms, necro-inflammation in the liver, and cirrhosis appear to be additional promoting factors. We studied the possible association between hepatocellular carcinoma (HCC) and the defective hepatitis D virus (HDV), a virus that requires the helper function of HBV. Patients infected with HDV and HBV develop HCC about 10 years earlier than those infected with HBV alone. Persistence of active HDV disease and low levels of "wild-type" HBV (i.e., secreting the hepatitis B surface antigen [HBsAg]) are associated with progressive liver disease and HCC. Therefore, HBV replication, in spite of being inhibited by HDV, appears to play a major role sustaining HDV pathogenicity. Detection of antibody to the hepatitis C virus (HCV) in many HCC patients raises the important question whether HCV has oncogenic potential. Clinico-epidemiological data show that the most severe forms of liver disease in patients with multifactorial liver damage occur in those infected with HCV. The prevalence of HBV markers in patients with cirrhosis, HCC, and HCV infection is higher than in individuals with comparable age and other diseases. HBV-DNA integration occurring early during HBV infection can persist in those with and without detectable HBsAg in their serum. Therefore, one can speculate that in patients with integrated HBV-DNA and concurrent HCV infection, cirrhosis and HCC may develop more easily than in patients without HBV-DNA integration. HCV hampering the immune system also might play a role in the genesis of HCC. The evidence that multiple hepatitis viruses are more frequently associated with HCC than infections of one virus alone has important practical consequences. It warrants the identification of high risk patients so that they can be monitored frequently for early diagnosis and treatment.

Adolescent↗
PubMed1994

Quantitative analysis of wild-type and HBeAg minus hepatitis B viruses by a sequence-dependent primer extension assay.

The ratio between wild-type hepatitis B virus (HBV) and HBV mutant, unable to secrete "e" antigen (HBeAg minus HBV) appears to be an important determinant of the outcome of chronic hepatitis B. Quantitative analysis of wild-type and HBeAg minus HBVs in the blood could be useful to monitor chronic hepatitis B patients. We developed a solid-phase minisequencing assay for both viruses using a primer-guided incorporation of a single labeled nucleotide on an affinity captured biotinylated amplified HBV-DNA template. A standard curve was constructed by mixing increasing quantities of wild type and mutant virus DNAs. The detection of wild-type and HBeAg minus sequences, ranging from 10% to 90% of overall viremia, was linear and reproducible till 0.1 pg/microliter of serum HBV-DNA. The assay yields numerical values and the ratio of incorporated nucleotides defines the relative proportions (%) of the two viral sequences with accuracy. We tested the sensitivity and accuracy of the minisequencing on mixed end point dilutions of wild-type and HBeAg minus reference sera and amplified products. The feasibility and reproducibility of the assay were tested in 35 sera from 21 HBsAg positive patients with chronic hepatitis B using both minisequencing and oligo-hybridization assays. A high correlation was found between the two assays (r = 0.957 P < 0.0001). In conclusion, the minisequencing assay provides a precise and reproducible quantitative analysis of wild-type and HBeAg minus HBVs in clinical specimens. It is proposed to study the relations between HBV heterogeneity and the course of hepatitis B and its response to therapy.

Base Sequence↗