Biomedical subjects

S Menzo

Publications and source records attributed to S Menzo.

41 records · Page 3Linked to original sources

PubMedDate not supplied

Hepatitis B virus preC mutants in human hepatocellular carcinoma tissues.

A comparative analysis of preC sequences of hepatitis B virus (HBV) in human hepatoma (hepatocellular carcinoma; HCC) tissues and non-tumoral liver samples from HCC patients was performed. Ten out of 17 HCC tissue samples exhibited an amino acid substitution at the level of the distal cysteine residue of the HBV preC region, while generation of a TAG translational stop codon was observed in 4 of these samples. Interestingly, substitution of the distal cysteine residue was not observed in non-tumoral liver (available from 8 of the 17 patients), thus suggesting either that a selection among different HBV variants occurs in HCC cells, or that modifications to the conformation and stability of the HBV capsid protein may play a role in the process of selection and escape of transformed liver cells.

Base Sequence↗

PubMedDate not supplied

Direct detection of HBV preC mutants in heterogeneous viral populations by a modified DNA sequencing method.

A modified method for the direct sequencing of double-stranded DNA products of PCR amplification is described and has been applied to the analysis of hepatitis B virus (HBV) preC/C region in samples from persistently infected patients with chronic hepatitis. Data was obtained from both hepatitis B e antigen (HBeAg)-positive and -negative chronic carriers. A high prevalence of mixed viral populations (wild-type genomes and mutated sequences with a TAG stop codon in the distal preC region at position 1895-1897) was shown in the HBeAg-positive group; a homogeneous (either mutated or wild-type) viral population was detected in all but one of the long-term HBeAg-negative, untreated chronic carriers, thus suggesting that pre-core mutants can be rapidly generated and selected during the natural course of HBV infection.

Base Sequence↗

PubMedDate not supplied

Complexity and dynamics of HIV-1 quasispecies.

The human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins mediate virus entry into target cells by binding receptors of the cell membrane and fusing viral and cellular structures. In particular, recent crystallographic studies have clarified the complex role of the glycoprotein gp120 in the early phase of the infection. In this context the inter- and intra-host variability of the HIV-1 gp120 poses a major problem for the development of effective methods of immunization against this virus. In the present report, the relevant aspects emerging from the study of HIV-1 variability are addressed and several methodological approaches to evaluate HIV-1 diversity discussed.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Viral dynamics and mutations in the pol gene during primary HIV-1 infection.

The understanding of viral dynamics and appearance of mutations during primary infection could be useful for the design of an efficient therapy. For this reason a cohort of samples from naive primary patients was examined. The results pointed out that only a few secondary mutations in protease gene (having no effect on resistance) were found, while a single mutation conferring resistance to non-nucleosides inhibitors of reverse transcriptase was found both in plasma and cerebrospinal fluid of a patient. As both the protease secondary mutations and the single non nucleoside reverse transcriptase mutation map far from the catalytical sites of the enzymes, neither one is able to impair viral fitness. Overall data suggest that treated donors carrying resistant strains may be in part unable to transfer them to the recipient, and/or virus in the recipient tends to revert to wild type. These results should be taken into account in the planning of early HAART treatment of HIV infection.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Molecular monitoring of human immunodeficiency virus type 1 infection.

Over the past few years, considerable technical effort has been directed to developing molecular methods that would allow an effective approach to the diagnosis of human immunodeficiency virus type 1 (HIV-1) infection and its monitoring. Indeed, quantitative molecular techniques have opened the way for a new type of direct study of untreated and treated HIV-1 infected subjects. The understanding of the immunopathogenesis of HIV-1 infection has increased significantly with the introduction of advanced virological and molecular methods for accurate quantitative analysis of HIV-1 activity; powerful methodologies answer (directly and in real time) most questions generated by pathogenic research and by the novel anti-viral strategies introduced in clinical practice. The data from pilot diagnostic applications of quantitative techniques have clarified important features of the natural history of HIV-1 infection. Moreover, an increasing amount of data indicate the need for second-level laboratory facilities for the clinical management of infected patients; virological aspects and some genetic features of the hosts concerning HIV-1 co-receptors (all the co-receptors so far identified are members of, or related to, the transmembrane, chemokine-receptor family) need to be elucidated for the complete diagnostic evaluation of HIV-1-infected subjects.

Antigens, Viral↗