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Biomedical subjects

A Ponzetto

Publications and source records attributed to A Ponzetto.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Hepatitis B markers in United States drug addicts with special emphasis on the delta hepatitis virus.

Hepatitis B virus and hepatitis delta virus co-infection in drug addicts has been well described in Europe, the latter agent appearing to have been introduced there in the mid-1970's. Currently, similar data are scanty among United States addicts. We therefore reevaluated 99 drug addicts from three different geographic locations in the United States who had participated in a Veterans Administration Cooperative Study between 1972 and 1975. Almost all were asymptomatic, and all had been subjected to liver biopsy because of prolonged aminotransferase abnormalities. Stored sera were tested for antibody to hepatitis delta antigen (anti-HD) by radioimmunoassay and available liver biopsies examined for hepatitis delta antigen (HDAg) by immunofluorescence. Overall, 19.2% were HBsAg positive, 9.1% HBeAg positive, 90% anti-HBc positive and 10.1%, positive for anti-HD. Anti-HD was identified in 42.1% of addicts who were HBsAg positive and in 3.3% who were anti-HBs positive. No correlation was found between HBeAg and anti-HD, but anti-HD was present significantly more frequently in those with chronic active hepatitis than in those with chronic persistent hepatitis. We conclude that hepatitis delta virus infection is common in HBsAg-positive drug addicts in the United States dating back to at least 1972 and probably earlier.

Adolescent↗
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Serial passage of hepatitis delta virus in chronic hepatitis B virus carrier chimpanzees.

Five consecutive passages of hepatitis delta virus in hepatitis B virus carrier chimpanzees were performed in order to further characterize the infectious and pathogenic nature of this naturally occurring defective virus. Three animals received identical inocula at fourth passage in order to assess individual animal variation as a factor in the course of infection and disease. Acute hepatitis delta virus infection occurred in all hepatitis B virus carrier chimpanzees as demonstrated by coincident intrahepatic hepatitis delta antigen, serum hepatitis delta antigen and serum hepatitis delta virus RNA followed by seroconversion to antibody to hepatitis delta antigen. In all animals, acute hepatitis was temporally associated with hepatitis delta virus infection and was self-limited. The incubation period to hepatitis shortened with passage, whereas biochemical and histologic evidence of liver diseases increased. The marked increase in liver disease with passage was not associated with increasing markers of hepatitis delta virus replication or expression, thus indicating that adaptation to the chimpanzee by serial passage resulted in increased hepatitis delta virus virulence. The duration of hepatitis due to hepatitis delta virus infection in three chimpanzees which received the same inoculum varied from 1 to 8 months. The observations of passage adaptation and individual host variation in this experimental model of hepatitis delta virus disease parallel known pathogenic variations in human hepatitis delta virus infection.

Animals↗
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The immunological diagnosis of HBsAg liver disease by combined screening for the e system in the serum and the HB core and surface antigens in liver biopsy samples.

Serological screening for HBeAg and anti-HBe, combined with the immunohistochemical localization of the hepatitis B core and surface antigen in 110 HBsAg carriers, established different immunological profiles indicative of the liver status and prognostic of the future absence or progression of the disease. Intrahepatic HBcAg and serum HBeAg appeared the most sensitive indexes of chronic and progressive liver disease, anti-HBe and large amounts of cytoplasmic HBsAg suggest, instead, the asymptomatic carrier state without liver damage. Only the nuclear localization of HBcAg in immunohistochemical studies was a reliable prognostic indicator of transition to chronicity; absence or presence of serum HBeAg was of no help in predicitng the outcome of acute HBsAg hepatitis.

Acute Disease↗
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Detection of a 5' UTR variation in the HCV genome after a long-term in vitro infection.

The TOFE lymphoid cell line from normal human bone marrow is susceptible to infection by a hepatitis C virus (HCV) serum strain. A sequence analysis of the 5' untranslated region (UTR) of HCV before and after long-term in vitro infection revealed one base substitution at position -158 (C > T) of the 5' UTR. We performed the direct sequencing of 5' UTR polymerase chain reaction-amplified sequences of the HCV genome: a) from the original serum-derived strain; b) from TOFE cell extracts 6 months post infection. This base substitution in the regulatory elements of the 5' UTR might be related to the ability of the virus to grow in cell culture.

Base Sequence↗
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Replication and multiplication of hepatitis C virus genome in human foetal liver cells.

The ability to obtain primary long-term cultures of human foetal hepatocytes maintaining liver differentiation characteristics in serum-free medium prompted us to test their susceptibility to hepatitis C virus infection. Using PCR, we detected the presence of the HCV RNA-positive strand in the supernatants and in the cells of the virus-infected hepatocyte cultures, at various times post-infection. Evidence of effective virus genome replication and multiplication was also based on the time-dependent appearance of the putative HCV RNA-negative strand, the detection of virus replicative intermediates and an increase in HCV genomic templates in the HCV-infected cells.

Cells, Cultured↗
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The human bone-marrow-derived B-cell line CE, susceptible to hepatitis C virus infection.

The euploid-diploid cell line CE, issuing spontaneously from a normal human bone marrow culture, displays B-cell differentiation and activation markers and is positive (> or = 90% of cells) for Epstein-Barr nuclear antigens. CE suspensions were inoculated with serum from a patient chronically infected with hepatitis C virus (HCV). After inoculation, the cells were regularly subcultured with a split ratio of 1:2 every 4-6 days. RNA extracted as late as 65 days after infection from the inoculated cells were positive by polymerase chain reaction for the 5' untranslated region of the HCV genome, and viral antigens were detected by immunofluorescence. Virus was also released from the infected cells into the medium. Intracellular HCV could be successfully passaged twice in CE cultures. On the basis of these findings, the CE cell line appears promising as a model for studying HCV replication and persistent infection in vitro.

Antigens, Differentiation↗
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Multiple rearrangements and activated expression of c-myc induced by woodchuck hepatitis virus integration in a primary liver tumour.

Woodchuck hepatitis virus (WHV) is a small, partially double-stranded DNA virus. Like the related human hepatitis B virus (HBV), WHV induces acute and chronic hepatitis and hepatocellular carcinoma (HCC) in its natural host. WHV DNA integration into c-myc and N-myc, resulting in deregulated expression of these genes, has been described previously in woodchuck HCC. We have analysed a woodchuck liver tumour in which WHV DNA was integrated in the c-myc gene. The virus insertion provoked multiple alterations in one c-myc allele, probably involving secondary deletions and mutations. Integrated viral DNA, including promotor and enhancer sequences, acted as an insertional mutagen, leading to enhanced expression of heterogenous c-myc transcripts ranging from 7.2 to 14 kb in size, strikingly longer than normal 2.3-kb c-myc RNA. These results provide an additional example in which the oncogenic activation of a myc gene by cis-acting effect of WHV insertion may play a critical role in virus-induced woodchuck HCC.

Animals↗
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Quantitation of hepatitis C virus RNA production in two human bone marrow-derived B-cell lines infected in vitro.

The ability of hepatitis C virus (HCV) to replicate in two B-cell lines, CE and TOFE, derived from bone marrow of healthy subjects was compared using qualitative and quantitative molecular methods. The presence of intracellular negative-stranded HCV RNA (replicative intermediate) was investigated by nested polymerase chain reaction (PCR) in the infected cultures at different times after infection. The amounts of positive-stranded HCV RNA (genomic RNA copies) synthesized and released from cells one week after in vitro infection were determined by competitive PCR after reverse transcription of viral RNA for the 5' viral untranslated region. In both cell lines, HCV RNA replication took place, but the TOFE cell line appeared to be a more efficient virus producer than the CE cell line. The TOFE cell line could be a valuable and reliable tool for basic and clinical HCV studies.

B-Lymphocytes↗
PubMedDate not supplied

Ultrastructural observations of viral particles within hepatitis C virus-infected human B lymphoblastoid cell line.

Hepatitis C virus (HCV)-infected TOFE cells, a human bone marrow-derived B-cell line, were studied by transmission electron microscopy (TEM). We reported the presence of virus-like particles, (VLPs) having a diameter of 45 nm on average, within the cytoplasm of HCV-infected cells and their absence in uninfected cells. The VLPs were mostly seen in dilated cisternae of endoplasmic reticulum (ER) and consisted of an electron-dense core and a membrane envelope with surface projections. In the HCV-infected TOFE cells, examination by TEM revealed tubular structures similar to those observed in liver cells of chimpanzees and humans infected by the virus. In some instances, the outer membrane of the particles was connected to the ER membrane, indicating possible virus budding into the cisternae. Rarely, coated vesicles containing a particle were seen. In most of the infected cells, enlarged cytoplasmic vacuoles filled with degenerative amorphous material were observed. The data suggest a flavivirus-like pattern of HCV morphogenesis in infected non-hepatic cells and identify lymphoblastoid TOFE cells as a valuable system for the study of the sequential steps of the infection process and the morphological effects produced by HCV infection.

B-Lymphocytes↗
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Hepatitis C virus infection of a Vero cell clone displaying efficient virus-cell binding.

The susceptibility of Vero cells and derivative cell clones to hepatitis C virus (HCV) infection was assayed by qualitative and quantitative polymerase chain reaction (PCR)-based methods. Cell extracts from Vero cells inoculated with HCV were tested for the presence of both positive and negative strands of HCV RNA; in parallel, cell-free HCV genomes were assayed in culture supernatant fluids. Quantitation of genomic HCV RNA molecules in infected cells by competitive reverse transcription PCR (cRT-PCR) indicated that HCV replication was more efficient in a derivative clone (named clone 10) than in parental Vero cells or other clones under study. Analysis of HCV-binding to cell receptors, performed by cRT-PCR quantitation of viral particles adsorbed to the cell surface, demonstrated a 10-fold higher virus-binding level of clone 10 than that of parental Vero cells. The results shown here indicate that the Vero clone 10 may constitute an efficient model system for analysing early events in HCV infection as well as a source of virus for diagnostic and biotechnological applications.

Animals↗
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Chronic Helicobacter pylori infection and migraine: a case-control study.

OBJECTIVE: To determine whether chronic Helicobacter pylori infection is a risk factor for migraine. BACKGROUND: Preliminary studies have shown a high prevalence of Helicobacter pylori infection in patients with primary headaches. METHODS: One hundred three consecutive patients with migraine were enrolled in the study and compared with a group of 103 matched controls. Helicobacter pylori infection was diagnosed by means of both (13)C-urea breath test and serology. RESULTS: Of patients with migraine, 30.1% were positive for Helicobacter pylori, compared with 31.1% of controls (P = NS). The odds ratio for migraine associated with chronic Helicobacter pylori infection was 0.96 (95% confidence interval, 0.51 to 1.80). Demographic, clinical, and psychological characteristics of Helicobacter pylori-positive migraineurs were compared with those of migrainous patients without infection. Helicobacter pylori-positive patients had a significantly (P<.05) lower incidence of food sensitivity than Helicobacter pylori-negative patients. No significant difference was found in any other feature examined. CONCLUSIONS: Our study suggests that chronic Helicobacter pylori infection is not more frequent in patients with migraine than in controls and that infection does not modify clinical features of the disease.

Adult↗
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[Chronic HCV hepatopathy and cryoglobulinemia. The associated clinical spectrum].

BACKGROUND AND AIM: The hepatitis C infection (HCV) has numerous extrahepatic manifestations owing to the systemic nature of the infection itself. HCV infects the cells that carry a CD 81 receptor and show a marked tropism for hepatocytes, bone marrow staminal cells and circulating lymphomonocytes. One consequence of this tropism is the activation of B lymphocyte clones with the consequent production of autoantibodies and cryoglobulins. The secondary event is the formation of circulating immune complexes which, having precipitated at an intravascular level, may cause part of the extrahepatic manifestations associated with these infections. METHODS: This retrospective study evaluated the manifestations correlated and/or associated with HCV hepatitis and mixed cryoglobulinaemia. RESULTS: This analysis showed that 75% of consecutively studied patients reveal clinically important extrahepatic manifestations. CONCLUSIONS: This underlines the "broad spectrum" action played by the hepatitis C virus in the host organism.

Adult↗
PubMedDate not supplied

[Infections and cardiovascular diseases on an ischemic basis. The case of Helicobacter pylori].

Cardiac and cerebrovascular diseases are an important cause of mortality in industrialized countries. "Classical" risk factors cannot fully explain epidemiological variations of these diseases. From several years infections have been linked to ischemic vascular events and recent publications pointed to the role of Helicobacter pylori, a Gram negative bacterium, involved in the pathogenesis of gastritis and peptic ulcer. Results on the association between this bacterium and acute myocardial infarction or stroke are controversial, due to the degree of studies heterogeneity. There is the need for extensive prospectic studies to evaluate the incidence of these diseases in relation to the presence of Helicobacter pylori infection. Interventional randomized studies employing an antibiotic treatment for patients affected by ischemic vascular diseases will rapidly answer the question of wheather Helicobacter pylori has a causal role in the pathogenesis of acute myocardial infarction and ischemic stroke.

Cardiovascular Diseases↗
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[Indications and limitations of 24-hour gastric pH-metry. Personal experience].

After a brief introduction regarding 24-hours gastric pH monitoring and a description of the instruments used, indications and the analysis of findings, the authors report their personal experience based on the study of 4 groups of subjects (healthy, hyersecretory, hyposecretory, dyspeptic). The analysis of pH-metries observed in these subjects show that 24-hour monitoring of gastric pH is a reliable method for assessing hypersecretion or hyposecretion of gastric acidity, whereas it is only of relative importance in essential dyspepsia. The authors therefore indicate the parameters to be taken into account in the evaluation of pH-metry findings in hypersecretory patients: 1) the percentage time of which pH is less than 1 (mean value 46.20 +/- 28.2);2) the pH pattern assessed according to the circadian rhythm which shows a prandial and post-prandial tamponade which is lower than normal with a rapid return of pH to extremely low values; 3) the visual graphic assessment for an overall judgement of pH patterns; and in hyposecretory patients: 1) the percentage time for which pH is higher than 7 (mean value 47.92 +/- 52.08); 2) enhanced pH levels ranging between 0 and 4 (mean percentage 9.67 divided by 27.08); 3) pH values at times 0, 1, 2, 3 which confirm hyposecretion in the meal causes a marked and long-lasting tamponade with pH levels above 6-7. Even in these cases the visual graphic assessment is important for an overall definition of 24-hour ph patterns.

Adult↗
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Alteration in cell-mediated immunity in patients with chronic active hepatitis. I. Lymphocyte subpopulations.

Absolute number of T and B lymphocytes were measured in the peripheral blood of 25 patients with biopsy proven HBsAg-positive Chronic Active Hepatitis (CAH), in 9 with Chronic Persistent Hepatitis (CPH), and in 25 HBsAg-negative healthy controls. In patients with CAH and cirrhosis total T lymphocytes were decreased; no difference were found between patients with CPH and normal controls. This data emphasize the importance of monitoring T-cells population in patients with HBsAg-positive CAH.

Adult↗