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Biomedical subjects

M Brunetto

Publications and source records attributed to M Brunetto.

13 recordsLinked to original sources
PubMed2006

European multicenter evaluation of high-density DNA probe arrays for detection of hepatitis B virus resistance mutations and identification of genotypes.

Polymorphisms along the hepatitis B virus (HBV) genome have an impact on disease outcome, sensitivity to antiviral treatment, escape from vaccination, and laboratory diagnosis. We have designed a diagnostic tool based on duplex amplification of the whole HBV genome and a high-density DNA chip designed to detect 245 mutations, 20 deletions, and 2 insertions at 151 positions and to determine the genotype of the virus in serum. Assay performances were evaluated with 170 samples, characterized by determination of viral load and sequencing of the Pol, S, and precore genes and the basal core promoter. One hundred fifty-three samples (90%) could be amplified and analyzed by the chip. Only two samples with more than 10(3) genome copies/ml could not be analyzed. Genotype had no impact on analytical sensitivity. Reproducibility studies showed no difference between repeats for codon and genotype determination. Genotype determination by sequencing and the chip were concordant in 148 of 151 samples. Twelve thousand one hundred sixty-one codons were analyzed by both techniques. Only 89.4% could be determined by sequencing, and among the remaining 11,335 codons, 92.8% were identical by sequencing and the chip. Failures to identify an amino acid by the chip were mainly due to reduced hybridization efficiency attributed to unexpected polymorphisms. Optimization of the chip-based reagent for the analysis of the HBV genome is ongoing. This first evaluation showed that DNA chip technology can provide important information in relation to the clinical management of chronic hepatitis B.

DNA, Viral↗
PubMed1999

Hepatitis C virus RNA profiles in chronically infected individuals: do they relate to disease activity?

Fluctuations of hepatitis C virus (HCV)-RNA serum levels were monitored in a multicenter study in 76 chronic HCV carriers who had been followed longitudinally without receiving antiviral therapy to assess their relation with the course of liver disease activity. Forty-four patients had normal transaminases over more than 2 years, while 32 additional patients had fluctuating levels. Viral load was measured in serial serum samples prospectively collected for 10 to 12 months in 54 patients and in sera stored yearly up to 8 years in an additional 22 patients. In patients tested monthly, a lesser extent of fluctuations was detected in cases with constantly normal transaminases as compared with those with fluctuating transaminases. In the former group, the mean difference between maximum and minimum values observed in each individual patient was 0.7 Log, while in the latter group, it was 1.3 Log (P =.0004). Most of these patients experienced, on average, three peaks of viremia over 1 year. The range of variation observed upon yearly testing was between 0.2 and 2.2 Log and did not reach statistical significance between the two groups. In conclusion, a careful viral replication profile can be achieved only by monthly testing, because longer time intervals could miss viremia fluctuations. HCV-RNA levels are more stable in asymptomatic HCV carriers than in patients with biochemical activity of liver disease.

Adult↗
PubMed1998

Colchicine in chronic hepatitis B: a pilot study.

RATIONALE: Because of its antifibrotic and anti-inflammatory effects, colchicine has been proposed as a treatment for liver disease. Early in vitro studies have demonstrated that colchicine blocks mitosis in the metaphase and inhibits DNA synthesis. AIM: A pilot study of hepatitis B virus (HBV)-related/HBV-DNA+ve chronic liver disease. PATIENTS: Nine biopsy-proven chronic hepatitis patients (three with cirrhosis) entered the study. Two of them were HBeAg+ve and seven were antiHBe+. All patients were HBV-DNA+ve/antiHBc IgM+ve (index values of anti-HBc IgM ranged from 0.370 to 1.200). All of them had a major contraindication to interferon therapy or refused antiviral treatment. The known persistence of positive HBsAg ranged from 2 to 21 years. METHODS: After informed consent, the patients received 1 mg colchicine a day orally for 5 days-a-week over 6 months. Testing for liver enzymes and viral markers was performed at the baseline and after 3 and 6 months. RESULTS: None of the patients experienced side-effects during the treatment. The two HBeAg+ve patients seroconverted to anti-HBe with a normalization of AST/ALT during therapy. Among the seven antiHBe+ve patients, four had a complete normalization of transaminases (one patient cleared the HBsAg with seroconversion to anti-HBs). Six of the nine patients were HBV-DNA-ve at the end of therapy and were still negative after 12 months of follow-up. CONCLUSION: These preliminary results suggest that colchicine might have an antiviral activity in HBV-DNA+ve chronic liver disease, and it could be regarded as an alternative therapy to interferon.

Administration, Oral↗
PubMed1998

Nonerasing dose readout in lithium fluoride crystals by positron lifetime spectroscopy.

The measurement of the mean lifetime of the positron (tau) in a lithium fluoride (LiF) chip which had been irradiated with up to 40 Gy from a 60Co gamma-ray source demonstrates a correlation between the positron mean lifetime and the dose which has been delivered to the crystal. This result points out the possibility of performing the readout of gamma-irradiated LiF thermoluminescent dosimeters by positron lifetime spectroscopy without changing the information stored in the chip significantly.

Electrons↗
PubMed1994

Hepatitis type C after orthotopic liver transplantation: reinfection and disease recurrence.

We determined the prevalence of hepatitis C virus markers and the clinical course in patients transplanted for terminal type C or non-A, non-B cirrhosis. Hepatitis C virus infection recurred in 16 of 17 patients (94%) with type C cirrhosis (seropositive for hepatitis C virus prior to surgery) and in 10 of 11 patients (91%) with non-A, non-B cirrhosis whose hepatitis C virus status prior to surgery had not been determined. Markers of hepatitis C virus were detected in 4 of 16 liver transplants whose donors tested negative for hepatitis C virus prior to surgery; this figure represents the risk of hepatitis C virus acquisition from external sources at or after transplantation. In 18 of 26 reinfected patients aminotransferases increased after grafting and remained elevated throughout the 14 to 79 (mean 46.5) months of follow up. The histological findings varied from mild or moderate hepatitis in 15 patients to severe active hepatitis in two patients. Two patients developed cirrhosis; one of them died of intercurrent infection while she was receiving immunosuppressive therapy for chronic rejection. Patients transplanted for hepatitis C virus or non-A, non-B liver disease are at high risk of hepatitis C virus reinfection. However the course of recurrent hepatitis C is most often mild and compatible with a normal life and an excellent survival rate.

Adult↗
PubMed1993

Expression of estrogen receptor mRNA in tumorous and non-tumorous liver tissue as detected by in situ hybridization.

Estrogen receptor mRNA was detected by a non-radioactive in situ hybridization assay in tumor and non-neoplastic liver tissues. A synthetic oligonucleotide complementary to the human estrogen receptor mRNA was 3'-labeled with digoxigenin-deoxyuridine triphosphate (dUTP). Hybrids were revealed by an alkaline phosphatase-conjugated anti-digoxigenin antibody. Fourteen primary hepatocellular carcinoma tissues (and one metastatic) were obtained at surgery from 15 patients. The corresponding non-neoplastic liver tissues were available in 13 cases. The estrogen receptor mRNA was detected in 11 tumorous and 7 non-tumorous liver specimens. The staining was cytoplasmic and involved the majority of transformed hepatocytes, whereas a less widespread and weaker signal was found in normal hepatocytes. Within non-neoplastic tissue, bile duct epithelial cells could also be occasionally stained, whereas other cell types, such as vasal endothelial cells, were negative. Appropriate controls established the specificity of the reaction. Detection of the estrogen receptor protein by immunohistochemistry in these same specimens was invariably negative. This in situ hybridization assay can therefore be used as a complementary tool to evaluate the estrogen receptor expression within liver cancer.

Adolescent↗
PubMed1993

Infectious hepatitis B virus variant defective in pre-S2 protein expression in a chronic carrier.

All human hepatitis B viruses characterized so far express three envelope proteins, pre-S1, pre-S2, and HBs, which are believed to function as binding proteins for the cellular receptor, as targets for immune-mediated virus elimination, and in virion morphogenesis and secretion. Here we report the characterization of infectious HBV variant genomes that are unable to express a pre-S2 protein and which were derived from serum of a highly viremic chronic carrier. Direct sequencing of the amplified pre-S region and sequencing of 50 cloned amplified pre-S DNA fragments revealed that in all molecules, in addition to numerous nucleotide changes, there were deletions of the pre-S2 translation initiation codon and three codons 54 nucleotides downstream thereof. No pre-S2 protein and altered pre-S1 proteins were found in the serum of the patient. Cloned infectious HBV DNA genomes having the pre-S region substituted by the variant pre-S region were replication competent in cultured hepatoblastoma cells. Morphologically normal virions were efficiently secreted and were infectious for primary human hepatocyte cultures. These data demonstrate that HBV devoid of pre-S2 protein can occur in vivo as a dominant or exclusive virus population and that expression of the pre-S2 protein is not essential for HBV replication, virion morphogenesis, secretion, or in vitro infectivity.

Adult↗
PubMed1991

Replicating and virion secreting hepatitis B mutant virus unable to produce preS2 protein.

Mutant HBV genomes unable to produce preS2 protein were identified in the serum of a highly viremic chronic carrier. By direct sequencing of the amplified preS region and by sequencing of 50 cloned amplified preS DNA fragments all molecules were found to have deleted the preS2 translation initiation codon and three amino acids 54 nucleotides downstream thereof. In addition, numerous amino acid changes, predominantly located between both deletions, were revealed. HBV-DNA genomes containing the mutated preS sequences were shown to be replication competent and to secrete efficiently virions that were morphologically and by the type of DNA encapsidated not distinguishable from wild-type virus. These data demonstrate that HBV with mutated preS sequences and unable to express preS2 protein can occur as a dominant or exclusive virus population in a highly viremic chronic carrier. The data also show that expression of the preS2 protein is not essential for HBV replication, virion morphogenesis and secretion.

Adult↗
PubMed1991

Diagnosis of Budd-Chiari syndrome by pulsed Doppler ultrasound.

Computed tomography and real-time ultrasonography may not be conclusive for the diagnosis of the Budd-Chiari syndrome; in many cases more information may be needed, especially on vascular alterations. Doppler ultrasonography provides qualitative data on flow direction and pattern, thereby contributing significantly to diagnosis. Eight cases in which hepatic vein patency was unclear and presence of intrahepatic vessels resembling hepatic veins raised problems of interpretation in real-time ultrasonography are described. In some cases, patency or occlusion of the upper portion of the inferior vena cava were difficult to identify with real-time ultrasonography. Doppler ultrasonographic investigation showed flow in the hepatic veins to be completely absent in two cases and reversed in another two. In the remaining four cases, a flat waveform was evident. Flow in the inferior vena cava was reversed in four cases and showed a flat waveform in three other cases. Portal vein thrombosis was detected in only one case, whereas the remaining seven patients showed slow hepatopetal flow. These findings demonstrate that absent or reversed flow in the hepatic veins and/or flat flow in the hepatic veins associated with reversed flow in the inferior vena cava may be considered diagnostic for the Budd-Chiari syndrome. For this series the sensitivity of Doppler ultrasonography was 87.5%.

Adult↗
PubMed1988

[Evaluation of the usefulness of ultrasonics in the diagnosis of cancerous cirrhosis. Comparison with CT].

Cirrhotic liver hepatocellular carcinoma (HCC) was evaluated with both US and CT. In a group of 600 cirrhotic patients 64 had HCC, which was confirmed at histology in 24 cases, and by disease evolution in the other 40; single focal degeneration was proven in 40 patients, multiple (2, 3 focal lesions), or diffuse degeneration (more than 3 focal lesions) in the remaining 24. Sixteen patients had associated portal thrombosis. US recognized 38/40 single HCC, 22/24 multiple or diffuse lesions, and 11/16 portal vein thromboses. Degeneration was most frequently hypo/isoechoic in small tumors, hyperechoic and mixed in large lesions. When small lesions are hyperechoic their differentiation from both hemangiomas and regeneration noduli is extremely difficult. In such cases CT is mandatory. US diagnostic accuracy is by far superior to that of CT: 95% vs 85% in single lesions and 91.6% vs 87.5% in diffuse forms. Overall accuracy is 93.7% for US and 85.9% for CT. The authors believe that US should be performed every 6 months on cirrhotic patients, so as to allow HCC to be detected in time for radical surgery, while CT should be performed only when doubts persist.

Adult↗