P E Valensin

Università degli Studi di Siena, Siena, Tuscany, Italy

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Publications (99)316.58 Total impact

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    ABSTRACT: Postmortem skin is widely used in the treatment of patients with severe burns. Skin specimens must be screened for transmissible agents including human immunodeficiency virus (HIV), hepatitis B (HBV) and C (HCV) virus, human T-cell lymphotropic virus (HTLV), cytomegalovirus (CMV) and Treponema pallidum. Four hundred and sixty-one cadaveric donors underwent serological and molecular microbiological (polymerase chain reaction, PCR) screening at Siena Skin Bank between 2000 and 2004. 74/461 donors (16.1%) were found ineligible under current regulations. These results are interesting in a local context and underline the importance of screening involving both routine serological procedures and molecular microbiological investigation. The latter has not been uniformly introduced in many countries and very limited data is available to assess its cost-benefit ratio in the field of skin donor screening.
    Burns 06/2006; 32(3):348-51. · 1.80 Impact Factor
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    ABSTRACT: Abstract The multiplex polymerase chain reaction (PCR) was applied for the detection of the Chlamydia trachomatis chromosome and plasmid. The multiplex PCR demonstrated a sensitivity of 0.8 fg of chlamydial DNA, corresponding to the detection of about 5 copies of the plasmid. Analysis of 195 genital specimens collected randomly from a female population, showed that the multiplex PCR is more sensitive and rapid than culturing for detecting Chlamydia trachomatis. Moreover, sequencing of the II variable domain of the ompl gene, directly from DNA of the clinical specimens, appears to be a simple and rapid method for determining serovar isolates.
    FEMS Microbiology Letters 01/2006; 130(2‐3):205 - 209. · 2.05 Impact Factor
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    ABSTRACT: To evaluate the impact of highly active antiretroviral therapy (HAART) on the course of hepatitis C (HCV) infection, we studied the biological and virological characteristics of 23 HCV/HIV-coinfected HAART-naive patients. The HCV genotype, HCV and HIV viral loads, serum alanine aminotransferase, CD4+ and CD8+ cell/mm3 were determined at baseline, 1 month, 6 months and 12 months after initiation of HAART. Results were analyzed both in terms of total population and of HCV genotype. The study of the total population suggests that this therapy did not determine a significant alteration of HCV viremia and levels of ALT, while a significant decrease in HIV viremia (-1.7log10 at one year from the start of HAART) and increase in CD4+ counts was observed (P < 0.005). The biological and virological parameters of HCV/HIV coinfection differed according to the HCV genotype. In particular, only genotype 4 showed a significant inverse correlation between HCV and HIV viral loads.
    Journal of Clinical Virology 03/2005; 32(2):151-5. · 3.29 Impact Factor
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    ABSTRACT: To compare three methods for using HIV-1 genotype to predict antiretroviral drug susceptibility. We applied three genotypic interpretation algorithms to 478 reverse transcriptase (RT) and 410 protease sequences for which phenotypic data were available. Sequences were obtained from clinical practice and from published sequences in the Stanford HIV-1 RT and Protease Sequence Database. The genotypic interpretation algorithms included: Stanford HIVdb program (HIVdb), the Visible Genetics/Bayer Diagnostics Guidelines 6.0 (VGI) and a genotypic interpretation program (AntiRetroScan, ARS) developed at the University of Siena, Italy. Genotypic interpretations were normalized to a three-level output: susceptible, intermediate and resistant. Discordances were defined as differences between genotype and phenotype for the same virus isolate. Discordances for which an isolate was considered susceptible by one test but resistant by another test were considered major discordances. The frequency of major discordances between genotype and phenotype was 10.6, 13.7 and 15.7% for ARS, VGI and HIVdb, respectively (P < 0.0001 for ARS versus HIVdb and for ARS versus VGI; P = 0.002 for VGI versus HIVdb). The correlation between genotype and phenotype was highest for non-nucleoside RT inhibitors and lowest for nucleoside RT inhibitors. Half of the major discordances involved stavudine, didanosine and zalcitabine. The concordance among the three genotypic algorithms was high, with weighted Kappa values ranging between 0.76 and 0.84 for the pairwise comparisons between each of the algorithms. Genotype interpretation algorithms correctly predict phenotype in 85-90% of cases, but the rate of concordance is not uniformly distributed among different drugs. These data provide insight into the potential additional benefit derived from phenotyping.
    Journal of Antimicrobial Chemotherapy 02/2004; 53(2):356-60. · 5.34 Impact Factor
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    Marcello Valassina, Maria Grazia Cusi, Pier Egisto Valensin
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    ABSTRACT: Toscana virus (Bunyaviridae family, Phlebovirus genus) is a sandfly fever virus responsible for human neurological infections. Sandfly viruses are transmitted by insect vectors (Phlebotomus species) and the infection is present in climatic areas that allow the life cycle of the vector. The arthropode-borne Toscana virus is the etiologic agent of meningitis, meningoencephalitis, and encephalitis. The frequency of this neuropathic infection increases in the summer months, peaking in August in the endemic Mediterranean areas (Italy, Portugal, Spain, and Cyprus). Infection diagnosis is carried out by molecular assays and immunoenzymatic tests, which are rapid and sensitive. Recent studies have investigated the antigenic properties of the viral proteins (nucleoprotein N and surface glycoproteins G1 and G2), to better understand their immunogentic role.
    Journal of NeuroVirology 01/2004; 9(6):577-83. · 2.85 Impact Factor
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    ABSTRACT: In a prospective study of 33 infants born to hepatitis C virus (HCV)-positive human immunodeficiency virus-negative mothers the vertical transmission of HCV occurred in 6.8%. The evolution of HCV infection in two babies was studied from birth up to 5 or 6 years of age, and the sequencing of the hypervariable region (HVR) of the putative envelope-encoding E2 region of the HCV genome was performed. The HVR1 sequence variability and the different serological profiles during follow-up could reflect the differences in HCV transmission routes, HCV genotypes, and clinical evolution of infection.
    Journal of Clinical Microbiology 09/2003; 41(8):3955-9. · 4.07 Impact Factor
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    ABSTRACT: Toscana virus is the most important agent responsible for meningitis in central Italy. We report a serosurveillance study, using an immunoenzymatic assay, of 360 serum samples harvested from a high-risk population occupationally exposed to Toscana virus in two regions of Italy, Tuscany and Piedmont. The results indicates a seroprevalence of Toscana virus of 77.2% in the forestry workers, particularly in the Tuscany region. This fact is strictly correlated with the ecological niches specific for the survival of Toscana virus arthropod vector.
    Clinical and Diagnostic Laboratory Immunology 06/2003; 10(3):483-4. · 2.51 Impact Factor
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    ABSTRACT: To investigate the distribution of drug-resistant HIV-1 variants in plasma RNA and peripheral blood monuclear cell (PBMC) DNA at treatment failure while on therapy and after stopping therapy. Fifty-eight patients failing their first highly active antiretroviral treatment while on therapy and 50 patients after a median of 18.6 weeks after treatment interruption following multiple treatment failures were analysed. Paired plasma HIV-1 RNA and PBMC HIV-1 DNA were used for genotypic antiretroviral resistance testing. Drug resistance was computed by using the Stanford on-line genotype interpretation system. The extent of drug resistance was larger in plasma RNA than in PBMC DNA in the on-therapy group (P=0.004) and in PBMC DNA than in plasma RNA in the off-therapy group (P=0.04). Interpretation of genotype based on PBMC DNA and plasma RNA in the on-therapy and in the off-therapy group would have missed detection of resistance to one or more drugs in 21 and 22% of the patients, respectively, compared to interpretation based on the other blood compartment. In a subset of 27 patients for whom a sample before stopping therapy was available, there was a significant decrease in the number of RNA (mean 8.1 to 5.3, P=0.004), but not DNA (mean 6.8 to 5.7, P=0.143), resistance mutations following treatment interruption. While plasma RNA is the material of choice for early detection of drug resistance while on therapy, analysis of PBMC DNA may additionally support and possibly improve sensitivity of resistance testing in the absence of therapy.
    Antiviral therapy 01/2003; 7(4):245-50. · 3.07 Impact Factor
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    ABSTRACT: In the present study we investigated the efficacy of a new potential vaccine constituted of the respiratory syncytial virus (RSV)-F protein associated with influenza virosomes (RSV-F/IRIV) in combination with the mucosal adjuvant Escheriagen (Escherichia coli heat-labile toxin), administered intranasally (i.n.) to BALB/c mice. After an intramuscular "priming" with influenza virus vaccine, group A of mice was i.n. immunized with of RSV-F/IRIV+heat-labile toxin (HLT), groups B and C were inoculated i.n. with F-RSV+HLT and IRIV+HLT, respectively. The results showed that the virosomal delivery system greatly potentiate immune responses in animals. All mice immunized with the RSV-F/IRIV+HLT developed a mucosal IgA response and a high level of serum IgG. A balanced Th1/Th2 cytokine profile was observed in mice immunized with RSV-F/IRIV+HLT, while a Th2 response was observed in mice immunized with RSV-F+HLT. Histological analysis of lung tissue of RSV challenged mice did not reveal a vaccine-enhanced pulmonary eosinophilia. These results show that i.n. immunization of BALB/c mice with RSV-F/IRIV in combination with HLT can be considered a promising approach for the development of an efficacious human vaccine.
    Vaccine 11/2002; 20(29-30):3436-42. · 3.49 Impact Factor
  • JAIDS Journal of Acquired Immune Deficiency Syndromes 09/2002; 30(5):533-5. · 4.65 Impact Factor
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    ABSTRACT: Acute meningitis is the most common neurologic disease that involves the central nervous system. The spectrum of infectious agents that cause neurologic infection is remarkably broad and numerous viruses are the most frequent cause of the aseptic meningitis syndrome. We applied a multiplex one-step method for the rapid detection of the genomic RNA of different neurotropic viruses: particles in the genus Enterovirus and Toscana virus, which are the most representative aetiologic agents in our country during the spring-summer period. We have evaluated the sensitivity and the specificity of the multiplex one-step test on positive controls and on RNA extracted from clinical samples harvested from 475 patients with meningitis hospitalized during the 1996-2001 period. The multiplex one-step RT-nPCR protocol allows for the detection of enterovirus and Toscana virus RNA in a single sample, by using, at the same time, a very small clinical sample volume. In our study we were able to diagnose 192 cases of meningitis by Toscana virus and 31 cases by enteroviruses out of 475 cases of meningitis utilizing the described one-step multiplex method.
    Diagnostic Microbiology and Infectious Disease 08/2002; 43(3):201-5. · 2.26 Impact Factor
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    ABSTRACT: To determine (1) the prevalence of Helicobacter pylori infection in male and female patients with reproductive disorders and controls; (2) the presence of anti-H. pylori antibodies in samples of follicular fluid, vaginal secretions and sperm; and (3) the existence of a structural homology between a major spermatozoa protein, tubulin, and H. pylori proteins. Serum samples from 167 patients with infertility and 837 age- and gender-matched controls (blood donors) were examined by enzyme-linked immunosorbent assay (ELISA) and Western blotting to determine the seropositivity for H. pylori infection. The presence of anti-H. pylori antibodies in samples of follicular fluid, vaginal secretions and sperm was determined using the same techniques. The possible cross-reactivity with spermatozoa of anti-H. pylori hyperimmune sera and human antibodies was studied by immunofluorescence. The N-acid homology of human tubulin with the principal H. pylori proteins was assayed by the WU-blastp program available on the Internet. The prevalence of infection was significantly higher in patients than controls (49.1% v. 33.5%, P < 0.001). Follicular fluids from infected patients contained specific antibodies in all cases, sperm samples in about 50% of cases, and vaginal secretions in a minority of cases. Sera to H. pylori whole antigens and VacA reacted with the tails and the pericentriolar area of human spermatozoa (which are rich in tubulin); sera to urease and heat-shock protein (Hsp) did not. Follicular fluids with anti-H. pylori antibodies immune reacted with spermatozoa. A linear homology was found between beta-tubulin and three H. pylori proteins, flagellin, VacA and CagA. H. pylori infection may increase the risk of developing reproductive disorders or worsen the clinical expression of this syndrome.
    European Journal of Gastroenterology & Hepatology 06/2002; 14(6):663-9. · 1.92 Impact Factor
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    ABSTRACT: Development of drug resistance is considered a major cause for failure of antiretroviral therapy in human immunodeficiency virus type 1 (HIV-1)-infected patients adherent to treatment. However, the rate of emergence and the significance of HIV-1 drug resistance in clinical practice have been not investigated thoroughly. Selection of HIV-1 variants that are genotypically resistant to protease inhibitors was studied in all the patients (n = 169) who completed at least 18 months of treatment with a protease inhibitor plus two nucleoside reverse transcriptase inhibitors at two urban Italian hospitals. HIV-1 carrying primary protease inhibitor resistance mutations was detected in 70 (41.4%) patients. The estimated proportion of patients developing genotypic resistance to protease inhibitors at 12 and 24 months was 18.3% (95% CI, 12.5-24.2%) and 33.9% (95% CI, 26.4-41.5%), respectively. Independent predictors of development of resistance to protease inhibitors were higher HIV-1 RNA levels at the nadir (P < 0.0001) and inclusion of ritonavir or saquinavir versus indinavir in the starting regimen (P = 0.0313). Resistance to protease inhibitors was strongly associated with a lower response to treatment, as shown by HIV-1 RNA load (P = 0.0001) and CD4 cell counts (P = 0.005). However, a linear increase in CD4 cell counts was maintained up to the end of follow-up even in the protease inhibitor-resistant population. Resistance to protease inhibitors develops in a relevant proportion of patients under long-term triple-drug therapy in clinical practice and is associated with virological treatment failure and limitation of CD4 cell increase.
    Journal of Medical Virology 02/2002; 66(2):143-50. · 2.37 Impact Factor
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    ABSTRACT: We investigated influenza virosomes as a TAA-gene delivery system for use in TAA-directed anti-cancer vaccine therapy. An engineered plasmid (GC90) expressing the parathyroid hormone-related peptide (PTH-rP), a protein secreted by prostate and lung carcinoma cells, was included in influenza virosomes (GC90V). The ability of GC90V to elicit a PTH-rP-specific cytotoxic T cell (CTL) response was demonstrated in BALB/c mice immunised with intranasal (i.n.) GC90V+/-adjuvant subcutaneous (s.c.) interleukin-2 (IL-2). A PTH-rP-specific CTL response with antitumour activity was also demonstrated in human peripheral blood mononuclear cells (PBMC) stimulated in vitro with GC90V infected autologous dendritic cells (DC). These results provide a rationale for investigating GC90V in clinical trials of anticancer vaccine therapy.
    European Journal of Cancer 12/2001; 37(16):2097-103. · 5.06 Impact Factor
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    ABSTRACT: The observation of many cases of mumps and mumps-associated CNS complications in vaccinees prompted us to perform an evaluation of the efficacy of four attenuated mumps virus (Urabe, Jeryl Lynn, Rubini and S12) vaccines. Two doses of vaccine were necessary to induce a good immunity in animals. The humoral and cell-mediated response induced in mice immunized intramuscularly or intranasally with these vaccines has been evaluated. Although the Urabe and Jeryl Lynn strains appear more immunogenic than the other strains and induce higher levels of IgG when administered intramuscularly, the S-12 strain administered intranasally induces a good IgG response. A marked specific CTL activity against mumps virus was observed in mice immunized intranasally with all the strains and, particularly, with the S12 strain. Thus, the intranasal immunization could be considered a possible alternative and efficient route of vaccination against mumps.
    Archives of Virology 08/2001; 146(7):1241-8. · 2.28 Impact Factor
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    Haematologica 08/2001; 86(7):782-3. · 5.94 Impact Factor
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    ABSTRACT: Four protein fragments which span the entire hemagglutinin-neuraminidase protein (HN) of mumps virus were expressed in HeLa cells and cell extracts were tested for their capability to induce neutralizing antibodies in mice. Fragment HN3 (aa 213-372) was able to induce the production of hemagglutination-inhibiting and neutralizing antibodies. When a subfragment of HN3, the synthetic peptide NSTLGVKSAREF (aa 329-340 of HN) was used for immunization, hemagglutination-inhibiting and neutralizing antibodies against mumps wild type virus but not against the Urabe Am9 vaccine virus were raised. The peptide could, therefore, contain a new epitope, which may be critical for protective host humoral immune response.
    Virus Research 05/2001; 74(1-2):133-7. · 2.75 Impact Factor
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    ABSTRACT: Samples of atherosclerotic tissue from 58 patients undergoing carotid surgery were analysed by tissue culture and PCR for Chlamydia pneumoniae; PCR was performed to detect Omp1, 16S rRNA and HSP-70 genes. To understand the active pathogenic role of C. pneumoniae, a reverse transcriptase-PCR (RT-PCR) assay was applied to detect the specific RNAs expressed either in the replicative form, or in the cryptic form found in chronic infection. The C. pneumoniae omp1 gene, encoding the major outer-membrane protein (MOMP), was detected in 13 of 58 samples. Among these, the result was confirmed in 11 samples after amplification of a further target, the 16S rRNA, and the presence of the HSP-70 gene, encoding heat-shock protein 70, was revealed in only five cases. All the samples were negative for evidence of specific RNAs by RT-PCR. The presence of genomic DNA and absence of specific RNAs in atherosclerotic tissue samples suggests a lack of an active metabolic or persistent infective role for C. pneumoniae. Thus, traces of C. pneumoniae DNA in these samples could be due to a degradative pathway of the host defensive cellular and biochemical mechanisms.
    Journal of Medical Microbiology 04/2001; 50(3):228-32. · 2.30 Impact Factor
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    ABSTRACT: The envelope glycoproteins G1/G2 of Toscana virus (TOSV) seem to have the most important protective role in stimulating antibodies against the disease in humans, as well as antibodies against the Nucleoprotein (N), a partial neutralizing activity. Mice immunized with TOSV recombinant Nucleoprotein developed a strong humoral response to the TOSV that revealed the presence of neutralizing antibody than in vitro assay. The neutralizing antibody titre of mice immunized with the whole TOSV was analyzed before and after absorption of the sera with the recombinant N protein. A decrease of the neutralizing activity was observed in the treated sera. Similar results were obtained absorbing human anti-TOSV positive sera with the recombinant N protein. This study was designed to identify the nature of antibodies produced against the N protein of TOSV in mice and to establish correlation with antibodies produced in humans by natural infection.
    Journal of Medical Virology 02/2001; 63(1):72-5. · 2.37 Impact Factor
  • Digestive and Liver Disease 01/2001; 32 Suppl 3:S182-3. · 3.16 Impact Factor