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Biomedical subjects

A Ponzetto

Publications and source records attributed to A Ponzetto.

At least 109 records · Page 6Linked to original sources
PubMed1986

Prevalence of the hepatitis delta virus in Rumania.

Epidemiological data obtained to date show that the delta agent is spread all over the world. In Rumania hepatitis B virus infection is widespread and is associated with a high incidence of chronic liver disease. To determine the prevalence of delta infection, sera from 373 patients with chronic liver disease were tested for HBV markers; 228 were HBsAg positive. Anti-HD was present in 190 sera (83.33%), which reveals a very high incidence and shows a higher frequency of the active forms of the disease. However, in contrast to other studies, we found a high incidence of HDV infection in chronic persistent hepatitis and hepatocellular carcinoma.

Hepatitis B Surface Antigens↗
PubMed1985

Epidemiology of hepatitis delta virus (HDV) infection.

Markers of hepatitis delta virus (HDV) infection have been detected all over the five continents. Geographical prevalence varied heavily: HDV infection is very rare in Far East Asia, but extremely frequent in Arabian countries, in Romania and in certain Indian populations of South America. In Europe and in the USA the infection is widely spread among high risk groups such as intravenous drug abusers and haemophiliacs.

Africa↗
PubMed1985

Serological diagnosis of acute viral hepatitis.

Fifty cases of symptomatic acute viral hepatitis presenting at the Washington, D.C., Veterans Administration Medical Center between 1976 and 1978 were tested for serological markers of hepatitis virus infection. The etiology of the acute hepatitis appeared to be hepatitis A virus in 20%, hepatitis B virus in 52%, non-A, non-B agents in 22%, delta hepatitis in 4%, and infectious mononucleosis in 2%. The diagnosis of type B hepatitis was difficult to verify because 10% of cases were seronegative for HBsAg and another 10% were seronegative by conventional testing for IgM antibody to hepatitis B core antigen (a putative marker of acute hepatitis B virus infection). Accurate serodiagnosis of acute viral hepatitis depends upon the correct application of testing for IgM antibody to hepatitis A virus, IgM antibody to hepatitis B core antigen, HBsAg, and tests for syphilis and mononucleosis.

Adult↗
PubMed1985

Radioimmunoassay and characterization of woodchuck hepatitis virus core antigen and antibody.

Solid-phase radioimmunoassays for woodchuck hepatitis virus core antigen (WHcAg) and antibody (anti-WHc) were developed. WHcAg in woodchuck liver homogenates was characterized by ultracentrifugation in CsCl gradients; both heavy (1.35 g/cm3) and light (1.31 g/cm3) cores were obtained from the liver of an animal during acute WHV infection, which is consistent with observations in hepatitis B virus infection in man. Endpoint titers of anti-WHc were higher in chronic WHV carriers than in animals recovered from acute infections. Both IgM and IgG anti-WHc antibodies were produced by infected woodchucks. A survey of colony woodchucks demonstrated that 88/89 animals having one or more markers of past or ongoing WHV infection were positive for anti-WHc. Thus, serum anti-WHc appears to be a sensitive marker of WHV infection.

Animals↗
PubMed1984

Transmission of the hepatitis B virus-associated delta agent to the eastern woodchuck.

delta agent of human origin was inoculated into four woodchucks chronically infected with woodchuck hepatitis virus (WHV). The animals developed delta infections with serologic patterns similar to those previously observed in human and chimpanzee infections. delta antigen was detected transiently in serum and liver and was followed by seroconversion to anti-delta antibody. Analogous to the chimpanzee model of delta infection, serum and hepatocyte markers of WHV were suppressed in the woodchuck during acute delta infection. The suppression of WHV DNA in serum was evident only during the time of delta-antigen positivity, while the inhibition of other WHV markers was more protracted. The delta antigen in woodchuck sera circulated as an internal component of a particle similar in size to the human delta particle (36-nm diameter) and was encapsidated by the woodchuck hepatitis virus surface antigen; delta antigen from infected woodchuck and chimpanzee livers had similar biophysical properties. Histologic analysis showed that experimental delta infection is associated with a transient acute hepatitis in woodchucks and loss of hepatocytes carrying WHV antigens. The lesions differed from the conspicuous hepatitis associated with reappearance of WHV replication. Hepatitis B-like viruses, therefore, appear to provide the requisite helper functions for delta replication and the woodchuck represents a useful model for study of the virology and pathology of the delta agent.

Animal Diseases↗
PubMed1984

Antigenic analysis of woodchuck hepatitis virus surface antigen with site-specific radioimmunoassays.

Monoclonal antibodies to five nonoverlapping antigenic domains of woodchuck hepatitis virus surface antigen (WHsAg) were used to develop site-specific radioimmunoassays. The assays were based on the solid-phase sandwich principle in which different combinations of individual domain-specific antibodies were used as immunoadsorbents and radioiodinated probes. Over 85% of the combinations tested were able to detect serum WHsAg, including those using the same antibody as immunoadsorbent and probe. The limits for antigen detection in one site-specific system ranged between 16 and 80 ng of WHsAg per ml. The antigenic similarity of serum WHsAg from 13 colony woodchucks was shown with several combination assay systems. WHsAg was equally immunoreactive in these assay systems whether obtained by immunoaffinity chromatography or standard rate zone centrifugation methods. Further site-specific analysis demonstrated that Formalin treatment of purified antigen did not affect the immunoreactivity of these WHsAg sites.

Animals↗
PubMed1984

Core antigen and antibody in woodchucks after infection with woodchuck hepatitis virus.

The woodchuck hepatitis virus is a naturally occurring hepatitis B-like virus that infects the eastern woodchuck. Direct immunofluorescence staining for woodchuck hepatitis virus core antigen in liver biopsies demonstrated the presence of this antigen in 14 of 17 chronically infected woodchucks, and in 8 of 10 woodchucks undergoing acute infections. Fluorescent localization of woodchuck hepatitis virus core antigen was typically cytoplasmic, and this was confirmed further by electron microscopy. Experimental infection with woodchuck hepatitis virus was achieved in four of four woodchucks inoculated with serum from chronic carrier woodchucks. All infected animals developed a self-limited disease characterized by seroconversion to antibodies against the major viral antigens (core and surface antigens); naturally acquired acute infection demonstrated a similar course. A chimpanzee seronegative for all markers of hepatitis B virus developed a subclinical infection after inoculation with woodchuck hepatitis virus.

Animals↗
PubMed1984

Delta virus infection and severe hepatitis. An epidemic in the Yucpa Indians of Venezuela.

Over a 3-year period, 149 Yucpa Indians in Venezuela developed hepatitis; 34 persons died and at least 22 developed chronic hepatitis. Children and young adults were primarily affected, especially males. Serologic testing showed that hepatitis B virus infection was highly endemic in this population, but also that 65% of patients had hepatitis B virus surface antigen (HBsAg) during or after illness. Most patients had evidence of delta-agent superinfection; 86% of HBsAg-positive patients had delta antibody, and delta antigen was found in specimens taken during autopsies on 7 of 9 patients. Serologic data suggested that most infections were due to delta superinfection of hepatitis B carriers, and that more than 60% of these infections progressed to chronic disease. Delta agent infection, and particularly delta superinfection of hepatitis B carriers, appears to be an ominous occurrence that may develop in populations among whom hepatitis B virus infection is endemic, and who have no other risk factor for delta infection.

Adolescent↗
PubMed1984

Antibody to the hepatitis B virus-associated delta-agent in immune serum globulins.

Fifty lots of immune serum globulin prepared by four United States manufacturers between 1944 and 1977 were tested for the presence and titer of antibody to the hepatitis B virus-associated delta-agent. Anti-delta was detected in 28 of the 50 lots (56%) of immune serum globulin at titers ranging from 1:10 to 1:400. Anti-delta was present in 75% (6 of 8) of lots produced between 1962 and 1965, in 77% (17 of 21) produced between 1967 and 1970, in 45% (5 of 11) produced between 1971 and 1972 and in none (0 of 9) produced since 1973. A single lot of globulin prepared from plasma that was collected in 1944 from United States Army soldiers also contained detectable anti-delta. These data indicate that delta-infection has been occurring among hepatitis B surface antigen (HBsAg) carriers in the United States since the 1940s. The decrease in prevalence of anti-delta in immune serum globulin lots coincided with the start of routine HBsAg screening of blood and plasma. The elimination of HBsAg-positive units from plasma pools has reduced levels of HBsAg and anti-delta and should have decreased the risk of transmission of both type B hepatitis and delta-hepatitis by plasma products.

Blood Donors↗
PubMed1984

Infections with the hepatitis B virus associated delta agent in an isolated West-African community.

The occurrence of delta agent (delta) infection in the native population of the isolated Gbawein and Wroughbarh Clan region of Grand Bassa County, Liberia was studied. Sera of 97 patients with epilepsy, 73 non-epileptic relatives, and 31 non-epileptic control subjects were tested for hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs) and antibody to delta antigen (anti-delta). Of the 201 individuals tested 76 (37.8%) were HBsAg positive; the overall infection rate (HBsAg and anti-HBs positives) was 68.7%. No correlation with clinical disease could be established. Markers of delta infection were detected in seven index cases. All subjects with anti-delta were HBsAg positive except one, who was anti-HBs positive with a low titre of anti-delta (less than 1:10(2)), which is indicative of a recent delta infection. Mothers of six delta infected index cases were available for testing, one was found HBsAg and anti-delta positive, while the other five were anti-HBs positive and anti-delta negative. No delta infections occurred in children of HBV negative mothers. Presence of delta markers varied significantly (P less than 0.02) among HBsAg carriers of the Kpelle (18%) and the Bassa (2%) language group. A comparable difference in delta markers was observed among HBsAg carriers of the Gbawein (17%) and the Wroughbarh (4%) clans.

Adolescent↗