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Biomedical subjects

A Ponzetto

Publications and source records attributed to A Ponzetto.

At least 127 records · Page 7Linked to original sources
PubMed1983

The woodchuck animal model of hepatitis B-like virus infection and disease.

As a model of virus-induced disease, the WHV/woodchuck system is at an early stage of development; yet, much progress has been made and there now exists considerable evidence that WHV causes serious liver disease with major parallels to HBV infection of man. The relatively short interval (4-5 yrs) from infection to end-stage disease in this model provides unique opportunities for definition of the natural history of HBV disease and the evaluation of various intervention strategies (e.g., vaccine prophylaxis and anti-viral therapy). Such studies are currently in progress in a number of laboratories.

Animals↗
PubMed1982

Multicentre study of prevalence of HBV-associated delta infection and liver disease in drug-addicts.

To assess the epidemiological and pathogenic effects of infection with the hepatitis-B-virus (HBV)-associated delta agent in addicts who take drugs parenterally, 225 symptomless addicts from Italy and 261 addicts with HBsAg-positive hepatitis from Italy, Denmark, Switzerland, and Ireland were tested for delta antigen (delta-Ag) and its antibody (anti-delta) by radioimmunoassay. 79 liver biopsy specimens from HBsAg-positive addicts were also tested for intrahepatic delta-Ag by immunofluorescence. Anti-delta was found in 9 (27%) of 33 of the symptomless HBsAg-positive addicts, in 13 (8%) of 156 of those without HBsAg but with anti-HBs, and in none of those negative for HBV markers. The prevalence of serum delta-Ag or anti-delta among addicts with HBsAg-positive hepatitis was 64% (104/161) in Italy, 44% (8/18) in Denmark, 33% (11/33) in Switzerland, and 31% (15/49) in Ireland. 32 of the 79 (40%)liver biopsy specimens from HBsAg-positive addicts showed positive delta-Ag immunofluorescence. Delta infection occurring simultaneously with HBV infection is common and possibly a major cause of liver disease in drug addicts who receive drug parenterally. The spread of delta infection in drug-using communities is not confined to one country, and the drug habit may represent the major means by which delta agent spreads in areas of the Western world where this infection is not endemic.

Adult↗
PubMed1980

A solid-phase enzyme immunoassay (EIA) for detection of HBeAg and anti-HBe.

A sensitive, reproducible and easily performed enzyme immunoassay (EIA) based on a sandwich technique is described for serological detection of HBeAg and anti-HBe. EIA appears to be 600 times more sensitive than immunodiffusion and counterimmunoelectrophoresis and its performance compares well with available radioimmunoassays.

Antibodies, Viral↗
PubMed1979

Normal lymphocyte interferon production in adult HBsAg-positive chronic active liver disease.

To challenge the hypothesis that interferon (IF) production in chronic hepatitis-B virus liver disease is defective, lymphocytes from 14 patients with chronic active liver disease (CALD); from nine patients with chronic inactive liver disease (CILD), and from six healthy chronic carriers (HCC) were stimulated by Newcastle Disease virus. The patients with CILD showed a weak IF response by comparison with the controls (P less than 0.0005), whereas IF production by CALD patients and the HCC did not statistically differ from IF production in the healthy hepatitis-B surface antigen negative subjects who served as controls. These results indicate that IF treatment of CALD does not rely on a completely proved background.

Adult↗
PubMed1979

An ultrastructural and immunohistochemical study on the delta antigen associated with the hepatitis B virus.

Thirteen liver biopsies in which the delta antigen was detected by immunofluorescence were studied by electron microscopy and immune electron microscopy with peroxidase labelled IgG and F(ab1)2 fraction obtained from a human antiserum containing high-titre anti-delta antibodies. The findings were compared with those obtained in 11 HBcAg positive and in two HBsAg negative controls. Neither unique particulate morphology nor any HB virus ultrastructural component were visualised in the delta positive specimens; 20-23 nm naked core particles were observed in 10 of 11 biopsies displaying the HBcAg in immunofluorescence. Delta positive nuclei frequently contained dense round structures of diameter varying between 20 and 30 nm with a soft indistinct edge. These granules did not exhibit characteristic ultrastructural features which enabled them to be distinguished from other granular material observed occasionally in nuclei of normal and diseased livers. However, their association with the delta antigen has been proved by the deposition on identical structures of peroxidase labelled anti-delta antibody. These results suggest that the delta antigen is unrelated to the Dane particle, the putative HB virus. The granules observed in the delta positive nuclei are composed of an amorphous matrix, possibly insoluble aggregates of the delta antigen.

Cell Nucleus↗
PubMed1978

Cell-mediated immunity to acetaldehyde in alcoholic liver disease demonstrated by leukocyte migration test.

To determine whether a sensitization to ethanol metabolites occurs in alcoholic liver disease, reactivity of lymphocytes to nontoxic amounts of acetaldehyde was studied by direct elaboration of migration inhibitory factor (MIF) production. Eighteen alcoholics with various degrees of biopsy-proven liver damage showed increased MIF production in response to acetaldehyde; the mean value of the group differed significantly from 15 healthy controls, 15 subjects with nonalcoholic liver disease, and 15 alcoholics without liver involvement (P less than 0.001, P less than 0.001, P less than 0.02, respectively). Among the alcoholics with liver disease, none individuals (50%) with histological signs of advanced alcoholic hepatitis showed the highest percentage of inhibition of migration; the value differed significantly from the remaining patients with lesser degrees of hyaline necrosis in liver biopsies (P less than 0.005). These results indicate that acetaldehyde is involved in the pathogenesis of alcoholic hepatitis. Clinically, this test might facilitate the selection of patients with alcoholic hyaline necrosis.

Acetaldehyde↗
PubMedDate not supplied

HLA-DR5 antigen. A genetic factor influencing the outcome of hepatitis C virus infection?

BACKGROUND: Prognosis may be quite different among individuals infected with hepatitis C virus (HCV): a chronic liver disease is believed to occur in half the patients while in the other half there are no signs of histologic progression of liver damage. The host immune response might play an important role in such different outcomes. A relationship has been shown between HLA genes and immune response to viral hepatitis B, but to our knowledge, no evidence of an association with HCV has been reported so far. We investigated whether HLA class II alleles might influence the outcome of HCV infection. METHODS: Eighty-seven individuals, positive for anti-HCV by second-generation enzyme-linked immunosorbent assay and recombinant immunoblot assay tests, enrolled from May 1, 1991, to June 31, 1992, were evaluated. Thirty-six were symptom-free subjects found to have HCV antibodies when screened for blood donation: they all had normal results of liver function tests, normal results of physical examination, and normal hepatobiliary ultrasonography. Fifty-one were patients diagnosed as having a chronic liver disease by percutaneous liver biopsy specimen; histologic assessment was chronic persistent hepatitis in 15, chronic active hepatitis in 28, and liver cirrhosis in eight. A group of 231 donors of platelets and bone marrow, negative for anti-HCV, was used as a control population. All participants were typed for HLA class II antigens (DR and DQ) using National Institutes of Health recommended microlymphocytotoxicity test and were followed up by means of alanine aminotransferase and HCV testing for at least 1 year. RESULTS: Frequency of HLA-DR5 antigen was higher in symptom-free anti-HCV-positive individuals (52.8%) than among HCV-related patients with chronic liver disease (13.7%). The difference was statistically significant (corrected P value = .005; 95% confidence interval, 19.6% to 58.6%); between DR5 and long-term evolution of hepatitis C, there was a negative association (relative risk = 0.142). Moreover, frequency of HLA-DR5-positive subjects appeared to be inversely proportional to severity of liver disease (52.8% in symptom-free patients, 26.6% in patients with chronic persistent hepatitis, 10.7% in patients with chronic active hepatitis, and 0% in patients with liver cirrhosis, P < .001). CONCLUSIONS: Our results point to a strict relationship between HLA haplotype and ability of immune response to influence the outcome of HCV infection. Presence of HLA-DR5 antigen appears as a protective factor against a severe outcome of chronic infection, being correlated with a benign evolution of the infection, often asymptomatic, or a less severe chronic liver disease.

Adult↗
PubMedDate not supplied

HCV infective virions can be carried by human platelets.

It has been previously demonstrated that platelets (PLTs) can bind and transport HIV-1 infectious virions. Hepatitis C virus (HCV)-HIV-1 co-infection occurs frequently among users of illicit intravenous drugs, thereby increasing the severity of HIV disease and the evolution towards chronic active hepatitis and hepatocellular carcinoma of HCV-related hepatitis. In the present study we investigated whether or not PLTs can carry HCV, and studied the binding mechanisms. Purified PLTs, obtained from healthy donors, HCV negative and HIV negative, were adsorbed with HCV-containing serum and then employed to infect a THP-1 monocytoid cell line. Replication of HCV was observed as shown by positivity for the E2 antigen within THP-1 cells, by indirect immunofluorescence; moreover, HCV-RNA was detected in supernatants of THP-1 cells at day 7 post-incubation with HCV-adsorbed PLTs. The binding of HCV to PLTs seems to involve fibronectin (FN), as already shown in the case of HIV-1. Indeed, treatment with RGD (Gly-Arg-Gly-Asp-Ser), the key oligopeptide of FN binding, inhibits the ability of HCV to be carried by PLTs in infective forms; the same phenomenon occurs with Mabs to FN. Moreover the infection of THP-1 cells seems to increase FN surface expression, as demonstrated by immunofluorescence tests.

Blood Platelets↗
PubMedDate not supplied

Effect of HCV infection on THP-1 monocytoid cells.

Hepatitis C virus (HCV) is the main cause of hepatocellular carcinoma in industrialized countries. HCV-HIV-1 co-infection occurs frequently among users of illicit intravenous drugs, thereby increasing the severity of HIV disease and the evolution of chronic active hepatitis towards cirrhosis and hepatocellular carcinoma. The present work shows that THP-1 monocytoid cells are susceptible to HCV infection, of strain 1b, and that this strain can induce cellular modifications in this cell line. Infection of HCV was demonstrated by positivity for the E2 antigen within THP-1 cells and by indirect immunofluorescence; moreover, HCV-RNA was detected in supernatants of THP-1 cells from day 7 post-inoculation. Cell shape and membrane surface antigens varied upon viral infection, which is also capable of inducing oxygen radicals. In particular we underline the relevant intracellular accumulation of ferritin that paralleled an increase of cell surface expression of the transferrin receptor. Evaluation of cellular events upon HCV infection in THP-1 cells may represent a useful tool with which to identify alteration in monocytes metabolism and to study therapeutic approaches for such alterations.

12E7 Antigen↗
PubMedDate not supplied

Cytoplasmic tubular structures in liver of HBsAg carrier chimpanzees infected with delta agent and comparison with cytoplasmic structures in non-A, non-B hepatitis.

Electron microscopic observations were carried out on five HBsAg carrier chimpanzees infected with delta (delta) agent and two chimpanzees infected with human non-A, non-B hepatitis. The cytoplasmic tubular structures, which have been recognized in the liver of chimpanzees infected with human non-A, non-B hepatitis, were found also in the liver of HBsAg carrier chimpanzees infected with delta agent. The quantity of the cytoplasmic structures in serial studies was associated with SGPT elevation rather than with expression of delta antigen in sera and liver tissues. This indicates that the cytoplasmic structures reflect a pathologic change of the hepatocytes in chimpanzees infected with delta agent or human non-A, non-B hepatitis. These and other similarities between the two agents suggest a similar nature.

Animals↗
PubMedDate not supplied

Histologic studies of severe delta agent infection in Venezuelan Indians.

To supplement a detailed epidemiologic study of an outbreak of viral hepatitis in Venezuelan Indians in isolated valleys, apparently resulting from delta agent infection, 10 autopsy specimens were studied histologically and immunocytochemically, and five biopsy specimens were examined. The patients were children and young adults and predominantly males. A sequence of hepatitis from focal necrosis with conspicuous small-droplet steatosis, through massive necrosis, prolonged postnecrotic collapse to early cirrhosis with massive collapse was postulated. The histologic changes tentatively suggest a cytopathic effect of the delta agent without significant indication of lymphocytotoxicity, at least in the parenchyma. Delta agent was demonstrated in hepatocyte nuclei in moderate amounts in the focal-necrotic stage and in isolated cells in the massive-necrotic stage, but in large amounts during the transition to cirrhosis. Whether these patients, in whom neither HBcAg nor HBsAg were demonstrable in the liver, suffered exclusively from superinfection of hepatitis B virus carriers and/or coinfection of hepatitis B virus with the delta agent remains to be resolved. Delta infection may occur in isolated settings with no relation to Italian origin, drug addiction, or polytransfusion. The infection is far more widely spread than previously assumed.

Adolescent↗