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.
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.
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 positivestranded 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.
Our preliminary data suggest that Epstein-Barr virus (EBV) is able to bind to and fuse with the surface membranes of hepatoma cell line Li7A. In order to obtain further evidence, we utilized the ...relief of rhodamine fluorescence to monitor whether fusion would also take place when Li7A cells were exposed to experimental conditions such as neutral or low pH. It is well known that for some viruses, protonation in the endosomal compartment is needed to trigger the fusion. We show, furthermore, that the rate and extent of fusion are not affected by pretreatment of the cells with agents known to elevate the lysosomal and ensodomal pH, such as chloroquine or NH
4Cl (lysosomotropic agent). By indirect immunofluorescence assay, in addition, we confirmed the binding of the EBV to the Li7A cell surface membrane. We attempted finally to correlate the above processes with successful infection of Li7A cells by EBV detected using the polymerase chain reaction technique. In spite of the apparent lack of viral receptor CD21, these nonlymphoid cells appeared susceptible to EBV penetration and infection through fusion with the plasma membrane at the surface of the cells.
A rapid method based on ion chromatography for the determination of SO2 in meat and cured meat is proposed. The method concerns a steam distillation, recovery in oxidant, then a dilution and HPIC ...analysis. The analytical procedure takes about 45 min. The method has been verified on a piece of meat spiked with a known amount of sulfite. The success of such check suggests the technique as a valid, simple and reliable alternative for the determination of SO2 in meat
Viene proposto un metodo rapido per la determinazione dell'anidride solforosa nei salumi e prodotti carnei mediante cromatografia ionica. Il metodo prevede una distillazione in corrente di vapore, raccolta su un ossidante, quindi diluizione e analisi cromatografica. L'analisi viene completata in circa 45 min. Il metodo e' stato verificato su un pasticcio di carne trattato con quantita' note di solfito. L'esito positivo della verifica suggerisce il possibile utilizzo di tale tecnica come alternativa semplice, affidabile e rapida nel controllo dell'aggiunta di SO2 nella carne
