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Biomedical subjects

G Venturi

Publications and source records attributed to G Venturi.

At least 19 recordsLinked to original sources
PubMed2002

Performance of an in-house genotypic antiretroviral resistance assay in patients pretreated with multiple human immunodeficiency virus type 1 protease and reverse transcriptase inhibitors.

An in-house genotypic antiretroviral resistance assay was evaluated by testing 32 plasma samples obtained from heavily pretreated human immunodeficiency virus type 1 (HIV-1)-infected patients failing multiple antiretroviral regimens. The same samples were also sent to Virco Laboratories for genotypic (VircoGEN) and phenotypic (Antivirogram) resistance analysis. Sequencing results obtained by in-house (HG) and VircoGEN (VG) genotyping were concordant for 387 of 400 (96.75%) drug resistance mutations. Genotype-based prediction of drug susceptibility for 13 currently licensed antiretroviral compounds were in agreement in 336 (80.78%) cases, partially concordant in 73 (17.54%) cases and discordant in only seven (1.68%) cases. VG indicated 'possible resistance' twice as much as HG. When genotype interpretation was compared with the Antivirogram phenotypic data, there were 27 (6.49%) and 23 (5.52%) wrong calls by HG and by VG, respectively. Both assays were more sensitive in detecting drug resistance than drug susceptibility (94.61 vs. 65.19% for HG, 80.84 vs. 56.91% for VG) and more specific in detecting drug susceptibility than drug resistance (93.62 vs. 73.49% for HG, 93.62 vs. 80.32% for VG). Rule-based algorithms can reliably interpret genotypic data obtained from most heavily pretreated patients. However, occasional genotypic patterns may be erroneously interpreted without resistance phenotyping.

Anti-HIV Agents↗
PubMed2000

Ultrasensitive in-house reverse transcription-competitive PCR for quantitation of HIV-1 RNA in plasma.

An ultrasensitive version of an 'in-house' reverse transcription-competitive polymerase chain reaction assay described previously for quantitation of human immunodeficiency virus type 1 (HIV-1) RNA in plasma was developed. The increase in sensitivity from 400 to 50 HIV-1 RNA copies/ml was achieved by pelleting virus particles from 1.8 ml plasma by centrifugation prior to RNA extraction, modifying competitor DNA structure and amounts, and redesigning primers. Quantitation of HIV-1 RNA in 130 samples tested previously by the standard assay showed that the two procedures yield comparable results (mean absolute difference, 0.26+/-0.20 log) and that the ultrasensitive version detects HIV-1 RNA below the threshold of sensitivity of the standard method. The ultrasensitive 'in-house assay' and the reference QUANTIPLEX HIV-1 RNA 3.0 had the same sensitivity and gave equivalent results (mean absolute difference, 0.19+/-0.11 log), as shown by parallel blinded testing of 47 plasma samples. Titration experiments with reconstructed plasma samples allowed the determination of a dynamic range of 50-500000 HIV-1 RNA copies/ml for the 'in-house' system. The interassay coefficient of variation for samples nominally containing 200, 4000 and 80000 HIV-1 RNA copies/ml were 33.4, 22.9 and 38.2%, respectively. The performance, turnaround time, and cost-effectiveness of this system make it suitable for medium-scale clinical application.

Centrifugation↗
PubMed2000

Antiretroviral resistance mutations in human immunodeficiency virus type 1 reverse transcriptase and protease from paired cerebrospinal fluid and plasma samples.

Twenty-four adults infected with human immunodeficiency virus type 1 (HIV-1) with central nervous system symptoms were studied for antiretroviral resistance mutations in HIV-1 RNA obtained from paired cerebrospinal fluid (CSF) and plasma samples. Paired sequences were obtained from 21 and 13 patients for reverse transcriptase (RT) and for protease, respectively. Mutations conferring resistance to the RT inhibitors zidovudine, lamivudine, or nevirapine were detected in 14 patients, including 11 pretreated and 3 drug-naive subjects. The mutation patterns in the 2 compartments were different in most patients. Genotypic resistance to protease inhibitors was detected in both plasma and CSF from 1 patient treated with multiple protease inhibitors. However, accessory protease inhibitor resistance mutations at polymorphic sites were different in plasma and CSF in several patients. Partially independent evolution of viral quasispecies occurs in plasma and CSF, raising the possibility that compartmentalization of drug resistance may affect response to antiretroviral treatment.

Adult↗
PubMed2000

Analysis of the HIV-1 nef gene in five intravenous drug users with long-term nonprogressive HIV-1 infection in Italy.

Great variability in the course of human immunodeficiency virus type 1 (HIV-1) infection results from a complex interplay between host and virus factors. Some of the patients with prolonged nonprogressive infection have been reported to harbor virus variants with gross deletions in the accessory nef gene that has been implicated in in vivo pathogenicity in simian and mouse models. To investigate the role of nef-deleted HIV-1 in long-term nonprogressor (LTNP) drug addicts in Italy the nef sequence from proviral DNA was analyzed from five LTNPs and five rapid progressor controls. Only small (2-12 amino acids) in-frame deletions and insertions were detected in the N-terminal polymorphic and variable regions obtained from three LTNPs and one rapid progressor. There was no evidence of premature termination of the Nef protein and all of the identified functional motifs were well conserved in both groups. Phylogenetic analysis showed interdigitation of nef sequences obtained from LTNPs and rapid progressors. The nef sequence of one LTNP, however, diverged significantly from those of the other patients. Availability of two additional blood DNA samples obtained previously from this subject allowed to detect evolution of nef at 14-17 years of HIV-1 infection, including progressive deletions. Although alterations of nef may be relatively frequent and continue to evolve in LTNPs, this study of a small number of patients does not indicate that gross deletions or loss of functional motifs play a major role in delaying or halting disease progression in infected drug abusers in Italy.

Adolescent↗
PubMed1999

Development and significance of the HIV-1 reverse transcriptase M184V mutation during combination therapy with lamivudine, zidovudine, and protease inhibitors.

To analyze the emergence and role of the lamivudine (3TC)-selected HIV-1 reverse transcriptase (RT) M184V mutation under triple therapy, we performed a retrospective study of 40 nucleoside RT inhibitor-pretreated and 16 drug-naive patients who were switched to combined treatment with zidovudine (ZDV) plus 3TC plus a protease inhibitor (PI). Plasma viral load and pol genotype were analyzed at baseline and after 24 and 48 weeks of combination therapy. Emergence of the M184V RT mutation at week 48 was detected in 3 of 16 (18.7%) initially drug-naive subjects as opposed to 21 of 40 (52.5%) ZDV-pretreated patients. Multivariate logistic analysis detected HIV-1 RNA load at week 24 as the best predictor of subsequent selection of the M184V mutant (p = .0121). Among ZDV-resistant study subjects at week 24 (n = 17), those with mutant RT M184V codon had a more favorable HIV-1 RNA slope than those with wild-type RT 184M codon (p = .0551). This trend was observed, although in a less evident manner, even in pretreated ZDV-sensitive patients. These findings suggest that development of the 3TC-resistance M184V mutation under triple therapy with 3TC, ZDV, and a PI may have unexpected beneficial effects in vivo in addition to those associated with resensitization of ZDV-resistant virus to ZDV.

Anti-HIV Agents↗
PubMed1999

Antiretroviral therapy with protease inhibitors in human immunodeficiency virus type 1- and human herpesvirus 8-coinfected patients.

Human herpesvirus 8 (HHV-8) is believed to play a role in the pathogenesis of Kaposi's sarcoma (KS) and possibly in other proliferative disorders often associated with human immunodeficiency virus type 1 (HIV-1) infection. Recent case reports have indicated resolution of KS and clearance of HHV-8 DNA from peripheral blood mononuclear cells (PBMC) in HIV-1-infected subjects following highly effective antiretroviral therapy, including HIV-1 protease inhibitors (PI), suggesting a possible activity for these compounds on HHV-8 replication. In the present study, the time course of PBMC HHV-8 DNA levels, plasma HIV-1 RNA load, and CD4+ T-cell counts were followed up in six coinfected subjects (four with and two without KS) under antiretroviral therapy with PI. A specific anti-HHV-8 role for PI was not consistently found, since fluctuation of HHV-8 viral load over time appeared to be independent of treatment. Nevertheless, our data support the hypothesis that KS patients may significantly benefit from PI therapy as an indirect consequence of partial restoration of immune functions following effective anti-HIV-1 combination therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Genotypic resistance to zidovudine as a predictor of failure of subsequent therapy with human immunodeficiency virus type-1 nucleoside reverse-transcriptase inhibitors.

To define factors predictive of failure to respond to nucleoside reverse-transcriptase inhibitors in human immunodeficiency virus type-1 (HIV-1)-infected subjects pretreated with zidovudine (ZDV), three groups of subjects shifted to double therapy with ZDV plus didanosine (ddI, n = 13), zalcitabine (ddC, n = 14), or lamivudine (3TC, n = 12) were retrospectively evaluated, with respect to addition of the second NRTI, at week 0 and week 24. Factors considered included duration of ZDV pretreatment, CD4+ cell counts, plasma HIV-1 RNA load, peripheral blood mononuclear cell HIV-1 DNA load, and HIV-1 DNA genotypic resistance to nucleoside reverse-transcriptase inhibitors. The three groups were well matched for baseline characteristics and did not differ significantly in virological and immunological response to the different combination treatments. Drug-specific resistance mutations were selected in more than half the cases by 3TC, but not by ddI and ddC. Low-level and substantial genotypic resistance to ZDV was detected 13 (33.3%) and in 19 (48.7%) patients at baseline, respectively, and evolved through week 24 in several patients. When subjects were divided into responders and nonresponders to the second nucleoside reverse-transcriptase inhibitor on the basis of a decrease of more than 0.5 log10 (n = 15) or less than 0.5 log10 (n = 21) in HIV-1 RNA, respectively, baseline genotypic ZDV resistance was the only independent predictor of failure in a logistic regression model (P = 0.003 or P = 0.024, depending on whether low-level resistance was considered or not, respectively). Thus, selection of ZDV resistance mutations may impair subsequent use of different nucleoside reverse-transcriptase inhibitor compounds.

Anti-HIV Agents↗
PubMed1999

Evaluation of cell-free and cell-associated peripheral blood human immunodeficiency virus type 1 RNA response to antiretroviral therapy.

Plasma human immunodeficiency virus (HIV) type 1 RNA load is the reference marker for response to antiretroviral therapy. To compare peripheral blood mononuclear cell (PBMC)-associated and plasma HIV-1 RNA response to treatment, HIV-1 RNA was quantified by reverse transcription-competitive polymerase chain reaction in 20 patients at 0, 12, and 24 weeks following addition of saquinavir to their treatment regimens. HIV-1 RNA was undetectable in 15 plasma samples but in only 2 PBMC samples (P=.002) and CD4 cell counts correlated more with PBMC than with plasma HIV-1 RNA load. Changes in HIV-1 RNA load in PBMC and in plasma were correlated, and the decrease was higher in plasma than in PBMC at weeks 12 (P=.002) and 24 (P=.017). Moreover, PBMC, but not plasma HIV-1 load, at week 12 was predictive of HIV-1 RNA levels at week 24 in both plasma (P=.004) and PBMC (P<. 001). Thus, measurement of PBMC HIV-1 RNA may be useful during antiretroviral therapy.

Anti-HIV Agents↗
PubMed1999

Clinical evaluation of an in-house reverse transcription-competitive PCR for quantitation of human immunodeficiency virus type 1 RNA in plasma.

An in-house reverse transcription (RT)-competitive PCR (RT-cPCR) for the quantitation of human immunodeficiency virus type 1 (HIV-1) RNA in plasma samples was developed and validated. The procedure involves (i) extraction of RNA with spin columns, (ii) ready-to-use bead-mediated RT, (iii) competitive PCR in a microtiter plate, (iv) agarose gel electrophoresis of the reaction products, and (v) densitometric analysis of the digitized image of the gel. Quadruplicate tests and dilution studies showed that the sensitivity and intertest coefficient of variability of the RT-cPCR are comparable to those of the reference AMPLICOR HIV-1 MONITOR test. The results obtained by the two assays with a panel of 45 clinical samples were in good agreement (mean difference, 0.36 +/- 0.25 log units). Analysis of 1,982 clinical samples by the in-house RT-cPCR yielded the typical range of plasma HIV-1 RNA levels with the expected inverse correlation between CD4 counts and HIV-1 RNA titers. In addition, testing of plasma from 36 subjects at weeks 0 and 4 with respect to the time of initiation of protease inhibitor therapy detected a significant decrease in HIV-1 viremia. The mean reduction in the HIV-1 RNA level was 0.914 log unit for those receiving saquinavir (P = 0.0210), 1.584 log units for those receiving indinavir (P = 0.0047), and 1.904 log units for those receiving ritonavir (P < 0.0001). The in-house RT-cPCR assay is simple to develop and perform and allows quantitation of HIV-1 RNA in 100 to 200 samples per operator per week. Since the cost is 1/8 to 1/10 of those of reference commercial assays, this procedure could be conveniently used in medium-scale laboratories.

Anti-HIV Agents↗
PubMed1998

Long-read direct infrared sequencing of crude PCR products for prediction of resistance to HIV-1 reverse transcriptase and protease inhibitors.

Patients infected with human immunodeficiency virus type 1 (HIV-1) are being treated with a number of different combinations of antiretroviral compounds that target the essential viral enzymes reverse transcriptase and protease. Different sets of HIV-1 mutations that confer drug resistance have been well defined; they allow reasonable prediction of the drug sensitivity pattern from analysis of the HIV-1 genotype in vivo. Since periodical monitoring of genotypic resistance is expected to improve clinical management in a large number of infected patients, practical and cost-effective methods are highly desirable to set at least medium-scale sequencing in clinical diagnostic settings. We present a complete protocol for direct sequencing of HIV-1 reverse transcriptase and protease-coding regions. Features making the system amenable to routine clinical use include: 1. Highly robust presequencing steps (plasma RNA extraction, reverse transcription, and nested PCR); 2. Direct use of the crude unpurified PCR product as the sequencing template; and 3. Use of infrared-labeled sequencing primers consistently allowing long reads, thus obviating the need for sequencing of both DNA strands.

Base Sequence↗
PubMed1997

Evaluation of the presence of 2-LTR HIV-1 unintegrated DNA as a simple molecular predictor of disease progression.

In a preliminary cross-sectional analysis of 109 human immunodeficiency virus type 1 (HIV-1)-infected subjects the presence of 2-long terminal repeat (LTR) unintegrated circular HIV-1 DNA in peripheral blood mononuclear cells (PBMC) was found to be associated with both symptomatic infection (P = 0.0037) and low CD4 counts (P = 0.0004). To investigate the prognostic significance of the presence of 2-LTR HIV-1 DNA, a subset of 23 2-LTR-negative and 25 2-LTR-positive asymptomatic individuals were followed up for 12-24 months. The two groups did not differ in terms of baseline CD4 counts, zidovudine (ZDV) therapy, and duration of HIV-1 infection. Longitudinal analysis of CD4 values did not indicate a significantly different CD4 outcome between the two groups. However, when only ZDV-treated subjects were considered, a significant (P = 0.042) decrease in CD4 counts was found at month 24 with respect to baseline in 2-LTR-positive (n = 12) but not in 2-LTR-negative (n = 11) patients. Moreover, when > 40% CD4 loss from baseline and/or development of CDC stage B or C symptoms were considered as indicators of disease progression, there was a significantly higher number of events in the whole 2-LTR-positive group than in the whole 2-LTR-negative group (P = 0.0197 at month 12, P = 0.0299 at month 18, P = 0.0373 at month 24). Thus, the presence of 2-LTR HIV-1 DNA in PBMC merits further investigation as a simple, qualitative, molecular predictor of disease progression and decreased response to antiretroviral therapy.

Cross-Sectional Studies↗
PubMed1995

Concordance between polymerase chain reaction and antibody detection in the diagnosis of human immunodeficiency virus type 1 infection.

A highly sensitive nested polymerase chain reaction (PCR) protocol was used to detect human immunodeficiency virus type 1 (HIV-1) DNA in peripheral blood mononuclear cells from 271 HIV-1-seropositive patients, 240 HIV-1-seronegative subjects at increased risk for HIV-1 infection, 51 serologically indeterminate individuals, and 120 healthy blood donors. PCR was carried out in a multiplex nested configuration with pol and env region primer sets. HIV-1 DNA was detected in all of the HIV-1 seropositive patients. In contrast, HIV-1 DNA was not detected in any of the either seronegative or serologically indeterminate subjects. Only one of 37 seronegative regular sexual partners of HIV-1-infected patients who were followed longitudinally was found to seroconvert to HIV-1. However, HIV-1 DNA and antibody results were concordant in the four samples obtained from this subject prior to and after seroconversion. These results show an excellent concordance between HIV-1 DNA and antibody detection for diagnosis of HIV-1 infection and suggest that long-term HIV-1 infection in the absence of detectable antibody is likely to occur at a very low frequency.

Blotting, Western↗
PubMed1994

Mortality study of asbestos cement workers.

The present study describes cause-specific mortality of asbestos cement workers in the Emilia Romagna region of Italy. The cohort included workers in ten factories, most of which started operating between 1955 and 1965. Asbestos, mainly chrysotile, constituted 10%-20% of the dry component of the mixture. Crocidolite range between 5% and 50% of total asbestos. Asbestos concentrations up to 44 ff/cc were reported prior to 1975, while in recent years they have usually been below 0-1 ff/cc. The cohort included 3341 workers who had at some time been employed in the ten factories under study. Their mortality experience was compared with that of the population resident in Emilia Romagna. Vital status was ascertained at 1989. Seventy-three subjects were lost to follow-up (2.2%). Mortality from all causes and from all types of cancer was increased in the cohort. Malignant neoplasms of the respiratory tract showed a significant increase (SMR: 134; 90% confidence interval: 101-175; 40 observed) due to lung cancer (SMR: 124; 90% confidence interval: 91-166; 33 observed) and neoplasms of the pleura, mediastinum, and other parts of the respiratory tract (SMR: 602; 90% confidence interval 237-1267; 5 observed). The discrepancy between observed and expected mortality mainly concerned subjects with at least 20 years of employment in the factories. Five more cases of histologically confirmed mesothelioma occurred after the end of follow-up.

Asbestos↗
PubMed1990

[Pigmentation of the oral mucosa from endodontic materials].

The Authors describe the clinical case in which a 30 years old male patient presents anomalous pigmentation of the oral mucosa after the endodontic treatment of the upper right central incisive. The mucosa's anomaly appeared at the height of the lower third of the root near the branch of an accessory endodontic canal previously filled and it was caused by the outlet of filling material. After the examination of this case, the Authors affirme the importance of an accurate anamnesis in order to obtain a correct diagnosis of the various kinds of pigmented lesions, distinguishing the etiology, the pathogenesis and the histologic patterns.

Adult↗