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Biomedical subjects

F Bortolotti

Publications and source records attributed to F Bortolotti.

At least 109 records · Page 6Linked to original sources
PubMed1989

Hepatitis B virus DNA forms in the liver of chronically infected individuals. Relation to replication profile.

To analyze the profile of HBV-DNA forms in the liver in relation to different levels of virus replication, liver biopsies from 52 chronic HBsAg carriers were studied by Southern blot analysis. Quantitative evaluation of the major HBV-DNA molecules was carried out by densitometry in 27 patients with ongoing hepatitis B virus (HBV) replication in the liver. Significant variations in the intensity of the different bands were noted in individual cases, but statistical correlation between the amount of single stranded forms and levels of serum HBV-DNA was not observed. In contrast, the amount of linear 3.2 kb HBV-DNA appeared to have an inverse correlation with levels of circulating virions. Only the 3.2 kb form was detected in three patients negative for serum HBV-DNA. In these cases with 'inactive' state of episomic HBV genome seroconversion to anti-HBe occurred from 12 months before to 4 months after the time of liver biopsy testing. This 3.2 kb form can therefore be interpreted as a pattern of transition from the replicative to the non-replicative state of the virus.

Antigens, Viral↗
PubMed1989

Lymphocytes treated with natural alfa-interferon produce a chemotactic factor for human neutrophils.

Lymphocytes stimulated with alfa-interferon released a chemotactic factor for neutrophils. The process was not inhibited by cycloheximide, whereas mepacrine completely inhibited release of the chemotactic activity. The chemotactic factor was resistant to storage, heat treatment and proteolysis. Recombinant alfa-interferon did not stimulate lymphocytes to release a neutrophil chemotactic factor.

Cells, Cultured↗
PubMed1989

Controlled proteolysis of mouse epidermal growth factor. An RP-HPLC and 1H-n.m.r. study.

Tryptic digestion of the mouse epidermal growth factor (mEGF) and the chromatographic separation of its proteolytic fragments by RP-HPLC affords the isolation of the pure hormone, of its 1-48 (Des(49-53)mEGF) and 1-45 (Des(46-53)mEGF) derivatives, and of the carboxyl-terminal pentapeptide W49-W50-E51-L52-R53. Kinetics of mEGF proteolytic degradation follows a two-state time-course: native mEGF being converted into Des(49-53)mEGF with an apparent half-time of 10 min; and Des(49-53)mEGF subsequently hydrolyzed to Des(46-53)mEGF with an apparent half-time of 7 h. Native mEGF and its proteolytic fragments have been characterized by 1H-n.m.r. spectroscopy. In the aromatic and aliphatic regions, the 1H-n.m.r. spectrum proved to be a sufficiently sensitive probe for following controlled proteolysis, and for analyzing the influence of the carboxyl-terminal sequence on the hormone conformation and stability.

Amino Acid Sequence↗
PubMed1988

Acute phase proteins in chronic and malignant liver diseases.

Six acute phase proteins (haptoglobin, alpha 1-acid glycoprotein, alpha 1-antitrypsin, alpha 2-macroglobulin, C reactive protein and transferrin) have been measured in the sera of chronic liver disease (CLD) patients with different aetiology (viral, autoimmune and alcoholic) and histology (steatosis, chronic persistent hepatitis, chronic active hepatitis, cirrhosis), and in patients with liver cancer. 1) The most striking changes concerned alpha 2-macroglobulin (increased) and haptoglobin (decreased) levels. 2) Transferrin was lower in alcoholic liver disease than in viral CLD, CRP was lower in autoimmune than in viral or alcoholic CLD, and alpha 1-acid glycoprotein was lower in viral and alcoholic CLD than in autoimmune CLD. Acute phase protein assay may prove useful in differential diagnosis, particularly when specific markers are not available (autoimmune, non A, non B, alcoholic liver diseases). 3) No significant differences related to aetiology (B, non A non B, D viruses) were observed in viral CLD. 4) Patients who progressed to CLD after acute viral hepatitis type B or non A non B did not show different APP levels from those who had recovered when tested 8-12 months after the acute phase. 5) The pattern of APP changes observed in primary liver cell carcinoma was different from both the cirrhotic pattern and the pattern presented by other tumours with or without liver metastasis.

Acute-Phase Proteins↗
PubMed1988

Chronic hepatitis in childhood: the spectrum of the disease.

During a multicentre study of chronic hepatitis in childhood diagnosed by biopsy, the spectrum of the disease has been evaluated in 196 consecutive patients, including 157 from Northern Italy and 39 from Southern Italy. Only 31% of patients in the former group and 27% in the latter were symptomatic when first seen: the majority of cases being seen after familial screenings for hepatitis B virus (HBV) markers or during intercurrent infections, thus suggesting that the frequency of chronic hepatitis in childhood might be largely underestimated in our area. In Southern and Northern Italy 83% of symptomatic and 95% of asymptomatic patients were hepatitis B surface antigen (HBsAg) positive in serum; only 15 (8.3%) of these children were born to mothers known to be HBsAg positive at delivery, but a high circulation of HBV was found in their families: in fact more than 65% of household contacts in Northern Italy and more than 90% in Southern Italy had serological evidence of past or ongoing HBV infection. These data indicate that, although familial screenings for HBV could have enhanced the percentage of HBsAg positive asymptomatic cases, chronic hepatitis in Italian children is mainly caused by HBV infection acquired in the familial setting through horizontal transmission. Such findings also emphasise the importance of mass vaccination of infants as the most effective means to prevent chronic type B hepatitis in childhood in our area. Among HBsAg positive children 55% had histological features of chronic active hepatitis and 85% were hepatitis Be antigen (HBeAg) positive in serum. Anti-HBe positive hepatitis was significantly more frequent in Southern than in Northern Italy in parallel with the significantly higher prevalence (17%) of hepatitis delta virus infection in that area. Of the 16 HBsAg negative cases included in the study three had autoimmune hepatitis, three Wilson's disease, one alpha1 antitrypsin deficiency, and nine had cryptogenic hepatitis, often associated to mild liver lesions resembling those seen in our adult patients with chronic non-A, non-B hepatitis unrelated to percutaneous exposure.

Adolescent↗
PubMed1988

Human erythrocyte transglutaminase: purification and preliminary characterisation.

Erythrocyte transglutaminase was purified by anion-exchange chromatography, size exclusion and affinity chromatography. Homogeneity was achieved by an additional step of HPLC size-exclusion chromatography. The molecular mass of the purified enzyme was calculated to be 65,000 Da by size-exclusion chromatography and sucrose-gradient centrifugation, and 92,000 Da by SDS-PAGE, thus suggesting a high degree of asymmetry. The amino-acid composition of erythrocyte transglutaminase differed substantially from that of the guinea-pig liver enzyme, notably with respect to the number of histidine, cysteine and acidic amino-acid residues. The enzyme has an absolute requirement for divalent cations for activity: calcium, manganese, and the lanthanides terbium and gadolinium activate the enzyme in decreasing order of efficacy, while no activity is displayed in the presence of magnesium. In the presence but not in the absence of calcium ions, the enzyme is rapidly inactivated by N-ethylmaleimide and by diethylpyrocarbonate suggesting that the cation influences the reactivity of amino acids essential for catalysis. When erythrocyte proteins are employed as amine acceptors in the presence of calcium, the erythrocyte transglutaminase appears to preferentially modify membrane-associated proteins, although, in the absence of calcium ions and exogenous amines, it displays a pH-dependent interaction with soluble proteins.

Amino Acids↗
PubMed1987

IgM antibody to hepatitis B core antigen in children with chronic type B hepatitis.

IgM antibody to hepatitis B core antigen (anti-HBc IgM) was investigated by an antibody-capture radioimmunoassay (serum dilution 1:4000) in serum samples from 31 untreated children with chronic hepatitis B who were followed prospectively for 1-7 years. At the start, all patients were positive for hepatitis B e antigen (HBeAg), and anti-HBc IgM was detected in 23 cases, including 15 out of 16 with chronic active hepatitis and 7 out of 14 with chronic persistent hepatitis. A significant positive correlation was found between anti-HBc IgM levels and severity of liver damage (P less than 0.05), while an inverse relationship was found between anti-HBc IgM levels and distribution of hepatitis B core (HBcAg) antigen in the liver as detected by immunofluorescence. In fact 75% of anti-HBc IgM positive patients showed a focal HBcAg pattern (less than 40% positive nuclei), whereas 87% of antibody negative cases exhibited a diffuse HBcAg expression (more than 60% stained nuclei). During follow-up, seroconversion from HBeAg to anti-HBe with subsequent remission of liver disease occurred in 82% of patients presenting with detectable levels of anti-HBc, including three out of seven cases with chronic persistent hepatitis, but in none of the cases that were initially negative (P less than 0.01). These results indicate that during the natural course of chronic hepatitis B in children, anti-HBc IgM levels in serum reflect the degree of host immune response to infected hepatocytes. The close correlation between anti-HBc IgM seropositivity and seroconversion from HBeAg to anti-HBe suggests that anti HBc IgM may have a prognostic value during the follow-up of children with chronic HBeAg positive hepatitis B.

Adolescent↗
PubMed1987

Prognosis of chronic hepatitis B transmitted from HBsAg positive mothers.

Nine children born to HBsAg positive mothers, who became chronic HBsAg carriers with associated liver disease, were followed for five to 10 years. Five children with active hepatitis or active cirrhosis at presentation achieved complete remission within six years, while three HBeAg positive patients with minimal histological lesions remained unchanged.

Female↗
PubMed1987

Definition of hepatitis B virus (HBV)-specific target antigens recognized by cytotoxic T cells in acute HBV infection.

We have investigated the specificity of cell-mediated cytotoxicity for autologous liver cells in 10 patients with acute hepatitis B in relation to the expression of hepatitis B virus (HBV) antigens and IgG on the surface of hepatocytes. Hepatitis B core antigen (HBcAg) was expressed on hepatocytes from six patients and hepatitis B surface antigen (HBcAG) from four, though always in association with HBcAg. Peripheral blood mononuclear cells (PBMC) were significantly cytotoxic in eight of the patients, and fractionation experiments revealed that the cytotoxic effect was equally mediated by T and non-T cells. Monoclonal antibody blocking experiments showed that HBcAg was the major target antigen recognized by T cells, although some inhibition of cytotoxicity was observed after pretreatment of target cells with monoclonal anti-HBs in patients with liver cell surface HBsAg. In contrast, non-T cells were not consistently inhibited by either monoclonal anti-HBc or anti-HBs. These findings further suggest that the HBV nucleoprotein serves as a target for recognition by cytotoxic T cells.

Acute Disease↗
PubMed1986

Gabexate mesylate inhibition of serine proteases: thermodynamic and computer-graphics analysis.

The inhibitory effect of gabexate mesylate, which is used therapeutically in the treatment of pancreatitis and disseminated intravascular coagulation, and as a regional anticoagulant agent for hemodialysis, has been measured on bovine factor Xa, bovine alpha-thrombin, human Lys77-plasmin, human urinary kallikrein, human urokinase, porcine pancreatic beta-kallikrein-B, and bovine beta-trypsin catalyzed hydrolysis of p-nitrophenyl esters of N-alpha-carbobenzoxy-L-arginine and N-alpha-carbobenzoxy-L-lysine. On the basis of enzyme:gabexate mesylate affinities, the serine proteases can be arranged as follows: human urinary kallikrein approximately porcine pancreatic beta-kallikrein-B much less than bovine beta-trypsin approximately bovine factor Xa approximately human Lys77-plasmin approximately human urokinase approximately bovine alpha-thrombin. The mode of binding of gabexate mesylate to the serine proteases conforms to the active-reactive site geometries observed in their complexes with natural and synthetic inhibitors. Differences in gabexate mesylate affinities for these proteases reflect structural differences at their primary specificity subsite, which have been investigated by comparative analysis of amino acid sequences and by computer-graphics techniques.

Animals↗
PubMed1986

Liver cirrhosis associated with chronic hepatitis B virus infection in childhood.

We evaluated the prevalence and the clinical features of liver cirrhosis associated with chronic hepatitis B virus (HBV) infection in a prospective study of 292 consecutive children who were chronic HBsAg carriers with increased aminotransferase activity. Liver histologic changes at presentation were consistent with cirrhosis in 10 (3.4%) patients (100% boys, mean age 4.0 +/- 3.3 years). In none of the remaining children, including 166 with histologic evidence of chronic active hepatitis, did the condition progress to cirrhosis during an observation period of 1 to 10 years. This lack of progression suggests that cirrhosis is an early complication of chronic HBV disease in some patients. A higher prevalence of delta infection and increased incidence of blood transfusions were observed in patients with cirrhosis, supporting the hypothesis that superinfection with delta or non-A, non-B agents may play a synergistic role. Eight of 10 patients had histologic features of disease activity at presentation, although only two had symptoms. During follow-up, persistence of disease activity was observed only in the three delta antigen-positive patients. None of the patients with inactive cirrhosis have developed signs of liver failure or portal hypertension.

Child↗
PubMed1986

Changes in serum hepatitis B virus (HBV) DNA positivity in chronic HBV infection: results of a long-term follow-up study of 138 patients.

In an assessment of the clinical relevance of serum hepatitis B virus (HBV) DNA testing in chronic HBV infection, changes in the presence of this marker were investigated by spot hybridization in 138 hepatitis B surface antigen (HBsAg)-positive patients with chronic liver disease who were followed up for one to eight years. Forty-one patients were treated with steroids, often with evidence of potentiation of viral replication, whereas 92 patients remained untreated and had no evidence of sigma agent infection during follow-up. Data analysis in these patients allowed us to determine the significance of testing for hepatitis B e antigen and for HBV DNA in the natural history of the infection. The findings indicate that sequential testing for serum HBV DNA may be of great importance in HBsAg chronic carriers with liver disease for adequate evaluation of HBV replication and for the contribution of HBV DNA to the clinical assessment of chronic hepatitis.

DNA, Viral↗
PubMed1986

Serum hepatitis B virus DNA in acute hepatitis type B.

Sera obtained within 7 days after clinical onset of acute hepatitis type B were positive for hepatitis B virus (HBV) DNA by spot hybridization only in 4 out of 45 patients who subsequently recovered, but in 10 out of 10 patients who instead developed chronic infection. These results indicate that in uncomplicated acute hepatitis B, virus replication is limited to an early phase of infection, often preceding the onset of clinical symptoms, and suggest that serum HBV-DNA may represent an early and predictive marker of chronicity.

Acute Disease↗