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Biomedical subjects

A Ponzetto

Publications and source records attributed to A Ponzetto.

At least 91 records · Page 5Linked to original sources
PubMed1990

Different outcomes of chronic hepatitis delta virus infection in woodchucks.

Hepatitis delta virus (HDV) superinfection of woodchuck chronic carriers of woodchuck hepatitis virus (WHV) results in acute and chronic disease. The different courses of disease mimicked the outcome of human HDV superinfection, making woodchucks valuable models for clinical studies of HDV. Ten of 11 woodchuck chronic carriers of WHV superinfected with HDV developed acute HDV infection with markers of viral replication in the serum and liver. One animal (DW128) had no serological markers of acute HDV infection. Nine of 11 (82%) superinfected animals developed chronic HDV infection. An unusual course of chronic HDV infection occurred in one woodchuck (DW128): no serum markers of acute or chronic HDV infection appeared but HDV RNA was detected in the liver, indicating that chronic HDV infection can occur without serological markers.

Acute Disease↗
PubMed1989

Hepatitis delta virus (HDV) and woodchuck hepatitis virus (WHV) nucleic acids in tissues of HDV-infected chronic WHV carrier woodchucks.

The molecular forms of genomic and antigenomic hepatitis delta virus (HDV) RNA and of woodchuck hepatitis virus (WHV) DNA and WHV RNA were studied in nonneoplastic liver (NL) tissues, hepatocellular carcinoma (HCC) tissues, and several extrahepatic tissues of chronic WHV carrier woodchucks acutely (two animals) and chronically (six animals) superinfected with HDV. HDV was shown to replicate in all NL and HCC tissues but not in any of the extrahepatic tissues analyzed, which included spleen, peripheral blood lymphocytes, kidney, ovary, testis, thymus, lung, and stomach. HDV RNA was present as species with molecular weights consistent with those of monomers, dimers, and trimers of both strand polarities, supporting the rolling circle model proposed for HDV RNA replication. WHV DNA levels in NL, HCC, spleens, and serum were 10- to 100-fold lower than the levels typically observed in chronic WHV carrier woodchucks not infected with HDV. WHV DNA replicative intermediates were rarely observed and only at very low levels, representing less than 10% of the total WHV DNA. By contrast, WHV RNA transcription was not significantly depressed and both primary WHV RNA transcripts, 2.3 and 3.6 kilobases, were observed in NL, HCC, spleens, and in one of the kidney tissues. In addition, a 2.6-kilobase WHV RNA transcript was found in the majority of the NL tissues.

Animals↗
PubMed1988

Delta hepatitis virus infection in Ethiopia.

The results of Hepatitis Delta virus (HDV) antibody determinations carried on 566 HBsAg positive serum samples from a population of 5270 Ethiopian military recruits are reported. The prevalence of anti-HDV among apparently healthy HBsAg carriers was 5.8%. The prevalence increases with age within the available range (18-30 years). Differences might exist by area of origin and ethnic groups. The distributions of HBV markers was similar in anti HDV positive and anti HDV negative individuals, possibly due to the relatively young age of the population and/or the hyperendemic condition of the area.

Adolescent↗
PubMed1988

Evidence for replication of hepatitis delta virus RNA in hepatocyte nuclei after in vivo infection.

Examination of a naturally infected human liver and experimentally infected chimpanzee and woodchuck livers by in situ hybridization showed that hepatitis delta virus (HDV) RNA was restricted to hepatocytes. Genomic RNA was 20-30 times more abundant than antigenomic RNA and was predominantly single-stranded while antigenomic RNA was predominantly double-stranded. In acute delta hepatitis, viral RNA was a more reliable marker of virus infection in single cells than hepatitis delta antigen (HDAg) while in chronic hepatitis both markers were usually present in the same cell. In all cases, viral antigen and RNA were localized predominantly to the nuclei of infected cells. Thus, replication of HDV RNA is closely associated with HDAg expression at the cellular and intracellular level and it is likely that this new class of defective animal RNA viruses replicates in the nucleus of the infected cells.

Animals↗
PubMed1988

Prevalence of delta antibodies among urban HBsAg-positive chronic liver disease patients in Egypt.

The prevalence of delta infection among urban Egyptians is reported for the first time. Sera of 44 HBsAg-positive chronic liver disease (CLD) patients and 48 asymptomatic HBsAg carriers were screened for antibodies to hepatitis delta antigen (anti-HD). Anti-HD was found in 21 (47.7%) of the patients compared with 4 (8.3%) of the asymptomatic carriers. The difference was statistically significant at the 0.001 level. Anti-HD was present in 14 out of 24 (58.3%) subjects with histological diagnosis of chronic active hepatitis, 4 of 9 (44.9%) with cirrhosis, and 3 out of 11 (27.2%) with chronic persistent hepatitis. This study points to a high prevalence of hepatitis delta virus in Egypt.

Adult↗
PubMed1987

Titration of the infectivity of hepatitis D virus in chimpanzees.

The infectivity of hepatitis D virus (HDV) was evaluated by intravenous inoculation of chimpanzees. HDV was present in the inoculum at a titer of 10(11) chimpanzee infectious doses (CID). In contrast, the titer of hepatitis B virus (HBV) in the same inoculum was 10(6) CID. All HBV-infected chimpanzees inoculated with less than or equal to 10(-11) dilutions of the HDV-positive plasma were superinfected; an animal receiving a 10(-12) dilution did not develop markers of HDV replication in serum or liver. All HDV-infected chimpanzees had marked elevations of serum alanine aminotransferase activities. The incubation period from exposure to development of hepatitis was inversely related to the dose of HDV inoculum, although the severity and duration of hepatitis were independent of it. All animals recovered and rapidly developed antibody to hepatitis D antigen.

Alanine Transaminase↗