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Biomedical subjects

M Clementi

Publications and source records attributed to M Clementi.

At least 199 records · Page 11Linked to original sources
PubMed1985

A serum-free growth of a human hepatoma cell line as a tool for hepatocarcinogenesis and virus gene expression.

The PLC/PRF/5 human hepatoma cells were grown in a serum-free, hormone-free, chemically defined medium; we recently characterized cell growth and hepatitis B surface antigen (HBsAg) production by these cells under these culture conditions, in the absence of interfering substances. Because of the biochemical and the antigenic properties of PLC/PRF/5 cell line showing a marked similarity to in vivo hepatocellular carcinoma, this cell line provides an in vitro system for the study both of hepatitis B virus (HBV) infection and the relationship between this infection and hepatocarcinogenesis. In this paper we describe the effect of several hormones, growth factors and drugs on growth and HBsAg production of PLC/PRF/5 human hepatoma cells. The results obtained indicate that a serum-free growth of these cells may be useful and facilitate studies either on hormone binding or on the effect of growth factors and drugs.

Carcinoma, Hepatocellular↗
PubMed1985

Effect of insulin on an insulin receptor of PLC/PRF/5 human hepatoma cell line.

A human hepatoma cell line (PLC/PRF/5) contains several copies of hepatitis B virus (HBV) DNA in integrated form and releases hepatitis B surface antigen (HBsAg) in the form of 22 nm particles in culture medium; studies of the supernatant fluid failed to provide evidence of the morphologically intact virion (Dane particle) or hepatitis B infectivity. In this paper we describe the effect of insulin on cell growth and HBsAg production by these cells; moreover we describe the insulin binding to specific cell membrane receptors. Data in our hands point to a different insulin binding related to different incubation conditions.

Binding, Competitive↗
PubMed1985

[Seroepidemiology of infection by hepatitis B virus in student nurses: some implications for vaccination policy].

To estimate the risk of hepatitis B virus (HBV) infection among student nurses, we measured the prevalence of HBV infection in 218 student nurses (192 female and 26 male nurses) and the annual attack rate in a subgroup of 117 subjects. In both studies sera were tested with an enzyme immunoassay for the presence of HBsAg, anti-HBc and anti-HBs. In the prevalence study 24 student nurses (11.1%) had a marker of prior HBV infection; the presence of both anti-HBc and anti-HBs was the most prevalent serologic pattern. 2 student nurses were HBsAg positive (0.9%). Prevalence of infection was strongly related to increasing age, while the occupation of the head of the family showed no effect. In the incidence study 7 subjects seroconverted in a year (6.2%): 6 acquired only anti-HBc and 1 only anti-HBs. These data suggested the hypothesis that the presence of anti-HBc alone (a pattern usually associated with past infections in which anti-HBs is no more detectable) may represent false positive results. The implications of such hypothesis are discussed with particular reference to prevaccination screening policy.

Adult↗
PubMed1984

Modulation of production of hepatitis B surface antigen by a human hepatoma cell line.

Three drugs were assayed for their capacity to inhibit hepatitis B surface antigen (HBsAg) production by the PLC/PRF/5 human hepatoma cell line. The effect on cell growth and HBsAg production of Cordycepin, 6-azauridine, and Hygromicin B is reported. Hygromicin B, a translation inhibitor unable to penetrate normal cells, greatly reduced HBsAg production by growing and confluent cells.

Anti-Bacterial Agents↗
PubMed1984

Insulin reduces HBsAg production by PLC/PRF/5 human hepatoma cell line. Brief report.

Although its action at the molecular level is not completely understood, insulin, as well as its antagonist glucagon, certainly plays an important role in the modulation of protein synthesis. In order to observe whether insulin is involved in virus gene expression, we studied its effect on PLC/PRF/5 human hepatoma cell line, which posses HBV DNA sequences integrated at several sites. While human insulin had no effect on cell growth and increased the production of two plasma proteins, a selective inhibitory effect on HBsAg production could be detected. This observation might be useful for further studies both on virus gene expression and insulin action at the molecular level.

Carcinoma, Hepatocellular↗
PubMed1984

Popliteal pterygium syndrome presenting with orofacial abnormalities. Report of a family.

A family with popliteal pterygium syndrome is reported: two children presented a mild form of the syndrome, while their mother exhibited full expression of the gene. Only 11 families with 29 affected members and 25 sporadic cases have been published. This malformation syndrome is inherited in an autosomal dominant pattern, but environmental factors or genetic heterogeneity cannot be excluded in sporadic occurrences. The variability of expression is discussed and a comparison with previously published familial cases is made: minor anomalies, if present in relatives of patients with full gene expressions, are as helpful in making the diagnosis as are major abnormalities. Careful evaluation of the proband's family is essential for diagnosis and subsequent genetic counselling.

Abnormalities, Multiple↗
PubMed1983

Induced underglycosylation of PLC/PRF/5 human hepatoma cells. Brief report.

The production of HBsAg and human plasma proteins by PLC/PRF/5 human hepatoma cell line was studied in the presence of glycosylation inhibitors. The data presented here suggest that HBsAg release in culture medium by these cells is not reduced by an inhibition of glycosylation and that Tunicamycin may play a role in a mobilization of the intracellular pool of antigen.

Carcinoma, Hepatocellular↗
PubMed1982

Complement-fixation test for rotavirus detection: comparison and analysis of different methods to reduce anti-complementary activity of some specimens.

The complement-fixation test may be used to detect rotaviral antigens directly in clinical specimens. However, a certain number of specimens tested for human rotaviruses by the complement-fixation test show an anti-complementary activity. By comparing eight techniques we analysed this anti-complementary activity and identified the best method for its reduction. Pretreatment of clarified supernatant of stool suspensions by some methods resulted in a reduction of anti-complementary activity, without reducing the sensitivity of the method. Clarified supernatants of 8/36 (22.2%) specimens were anti-complementary; this anti-complementary activity was best removed by absorption with fetal calf serum or calf albumin. Such treatment offers practical means of increasing the specificity of complement-fixation test. Some observations suggest that the anti-complementary activity of stool suspensions may be frequently due to presence of one or more chelating agents that may be in faecal specimens.

Absorption↗