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Biomedical subjects

S Rusconi

Publications and source records attributed to S Rusconi.

At least 19 recordsLinked to original sources
PubMed2003

Declining incidence of AIDS and increasing prevalence of AIDS presenters among AIDS patients in Italy.

Presented here are the results of a cohort study conducted on 3,483 consecutive HIV/AIDS patients between January 1993 and December 2000 to determine trends in AIDS incidence and presentation. The incidence of AIDS was calculated in the general population and examined further according to gender, age (< or = or >49 years), and heterosexual behaviour as a risk factor for HIV. Multivariate analysis was used to identify variables associated with AIDS presenters (defined as patients diagnosed with AIDS within 1 month of the first HIV-positive test). The numbers of patients with AIDS classified as (i) AIDS presenters, (ii) known HIV-positive patients on antiretroviral treatment, and (iii) known HIV-positive patients not receiving antiretroviral treatment were calculated. The overall incidence of AIDS decreased over time, mainly due to the lower number of patients on antiretroviral treatment developing AIDS. Factors associated with a higher risk of being an AIDS presenter were male gender and year of HIV diagnosis. Among patients with AIDS, the proportion of AIDS presenters increased from 13.8% prior to 1997 (when protease inhibitors were introduced in Italy) to 32.5% after 1997. Variables predictive of being an AIDS presenter were male gender, age at diagnosis, and AIDS diagnosis in the years 1997-2000. Heterosexuals had a higher risk of being AIDS presenters and a lower risk of being HIV-positive and not receiving antiretroviral treatment than intravenous drug users. In Italy, AIDS occurs mainly in subjects unaware of their HIV status (especially males, the elderly, and those infected heterosexually) or in patients refusing antiretroviral therapy (mainly intravenous drug users who do not refer to specialised centres).

AIDS-Related Opportunistic Infections↗
PubMed2002

[Cornea donation: role of the local coordinator in monitoring and implementation].

BACKGROUND: In order to contribute to the dissemination of an organ and tissue donation culture, the authors report the results of a retrospective investigation into the donation of corneas for transplantation relative to the period from January 1997 to December 2001 at a leading hospital in the Milan area. METHODS: All cases of intra-hospital death (n=2137) were considered. The adoption of a selection protocol for potential donors, in accordance with the indications of the North Italy Transplant program, and constant monitoring on the part of the local coordinator, led to the collection of 348 corneal flaps using the procedure whereby all deaths have to be notified to the Health Department. RESULTS: Over this period, the donors/deaths ratio increased from 2.1 to 17.6%, while the collection index (real donors/potential donors including those wrongly excluded) increased from 40.8% in 1999-2000 to 67.8% in 2001. Most involved in the donor selection activity were the intensive care centres with an increase for Resuscitation of 12.7% and for First Aid of 33%, to a lesser extent non-intensive centres (increase of 11.2%). The causes of exclusion from cornea collection in the last three-year period were clinical contraindications in 51.2% of cases (sepsis, blood transfusions, diseases of the central nervous system of unknown aetiology), failure to activate the procedures in 17.4% of cases, opposition in 17%, unsuitability of the corneal tissues in 11.3%, inadequate age in 3%. CONCLUSIONS: The results obtained indicate good prospects for technical implementation and for the development of a donation culture in respect of other organs and tissues.

Corneal Transplantation↗
PubMed2001

Differential disappearance of inhibitory natural killer cell receptors during HAART and possible impairment of HIV-1-specific CD8 cytotoxic T lymphocytes.

BACKGROUND: Highly active antiretroviral therapy (HAART) is associated with a decrease in viral replication to undetectable levels and with an increase in CD4 T lymphocytes. Residual HIV-1 replication occurs together with incomplete recovery of cytotoxic CD8 T lymphocyte (CTL) numbers and function. We sought to determine whether expression of HLA class I-specific inhibitory natural killer receptors (iNKR) on the CTL of patients who had been treated successfully with HAART for 24 months could be involved, at least in part, in residual CTL functional inhibition. METHODS: Two-colour cytofluorometry was used to analyse the expression of six different iNKR including p58.1, p58.2, p70, p140, CD94/NKG2A and LIR1/ILT2 on the CD3, CD8 lymphocytes of eight patients with successful long-term suppression of viral replication before and after 3, 6 and 24 months of HAART. Healthy subjects were analysed as controls. HIV-1-specific cytotoxic activity was determined after 24 months of HAART in the presence and absence of iNKR-masking. RESULTS: No significant reduction of iNKR expression on CD8 T cells was observed by 6 months. Expression of p70 and p140 was inversely correlated with the increasing CD4 numbers. After 24 months CD8 T-lymphocytes expressing p58.1, p58.2, p70, p140 and CD94/NKG2A returned to levels indistinguishable from those of the healthy controls. A significantly increased proportion of CD8 CTL still expressed LIR1/ILT2, a receptor with broad HLA-class I specificity. Functional analysis of freshly separated cells revealed that the disruption of the interaction between LIR1/ILT2 and HLA-class I could partly restore HIV-1-specific lysis. CONCLUSIONS: A decrease in CD3CD8iNKR cells is observed beyond 6 months of HAART. In some patients functional impairment due to LIR1/ILT2 expression may persist even after 24 months of successful HAART.

Adult↗
PubMed2001

Serine/threonine protein phosphatase 5 (PP5) participates in the regulation of glucocorticoid receptor nucleocytoplasmic shuttling.

BACKGROUND: In most cells glucocorticoid receptors (GR) reside predominantly in the cytoplasm. Upon hormone binding, the GR translocates into the nucleus, where the hormone-activated GR-complex regulates the transcription of GR-responsive genes. Serine/threonine protein phosphatase type 5 (PP5) associates with the GR-heat-shock protein-90 complex, and the suppression of PP5 expression with ISIS 15534 stimulates the activity of GR-responsive reporter plasmids, without affecting the binding of hormone to the GR. RESULTS: To further characterize the mechanism by which PP5 affects GR-induced gene expression, we employed immunofluorescence microscopy to track the movement of a GR-green fluorescent fusion protein (GR-GFP) that retained hormone binding, nuclear translocation activity and specific DNA binding activity, but is incapable of transactivation. In the absence of glucocorticoids, GR-GFP localized mainly in the cytoplasm. Treatment with dexamethasone results in the efficient translocation of GR-GFPs into the nucleus. The nuclear accumulation of GR-GFP, without the addition of glucocorticoids, was also observed when the expression of PP5 was suppressed by treatment with ISIS 15534. In contrast, ISIS 15534 treatment had no apparent effect on calcium induced nuclear translocation of NFAT-GFP. CONCLUSION: These studies suggest that PP5 participates in the regulation of glucocorticoid receptor nucleocytoplasmic shuttling, and that the GR-induced transcriptional activity observed when the expression of PP5 is suppressed by treatment with ISIS 15534 results from the nuclear accumulation of GR in a form that is capable of binding DNA yet still requires agonist to elicit maximal transcriptional activation.

Active Transport, Cell Nucleus↗
PubMed2001

Transactivation specificity of glucocorticoid versus progesterone receptors. Role of functionally different interactions of transcription factors with amino- and carboxyl-terminal receptor domains.

A major unanswered question of glucocorticoid and progesterone action is how different whole cell responses arise when both of the cognate receptors can bind to, and activate, the same hormone response elements. We have documented previously that the EC(50) of agonist complexes, and the partial agonist activity of antagonist complexes, of both glucocorticoid receptors (GRs) and progesterone receptors (PRs) are modulated by increased amounts of homologous receptor and of coregulators. We now ask whether these components can differentially alter GR and PR transcriptional properties. To remove possible cell-specific differences, we have examined both receptors in the common environment of a line of mouse mammary adenocarcinoma (1470.2) cells. In order to segregate the responses that might be due to unequal nucleosome reorganization by the two receptors from those reflecting interactions with other components, we chose a transiently transfected reporter containing a simple glucocorticoid response element (i.e. GREtkLUC). No significant differences are found with elevated levels of either receptor. However, major, qualitative differences are seen with the corepressors SMRT and NCoR, which afford opposite responses with GR and PR. Studies with chimeric GR/PR receptors indicate that no one segment of PR or GR is responsible for these properties and that the composite response likely involves interactions with both the amino and carboxyl termini of receptors. Collectively, the data suggest that GR and PR induction of responsive genes in a given cell can be differentially controlled, in part, by unequal interactions of multiple receptor domains with assorted nuclear cofactors.

Animals↗
PubMed2001

Predictive role of the three-month CD4 cell count in the long-term clinical outcome of the first HAART regimen.

The aim was to evaluate whether the three-month CD4 cell counts are a reliable predictor of the long-term clinical outcome of HAART-treated patients, by an observational study of 585 patients initiating HAART in a clinical setting. Clinical failure was defined as the occurrence of new or recurrent AIDS-defining events or death, and was analysed by means of intention-to-treat, univariate and multivariate analyses. An adjusted Cox regression model was used to evaluate the effect of three-month CD4+ counts on clinical outcome. Clinical failure occurred in 65 patients (11.1%) during a median follow-up of 31 months (1-65) as a result of new AIDS-defining events (ADEs) in 48 patients, ADE recurrence in six, and death in 11. The mean (median; range) CD4+ counts were 156/microL (155; 4--529) in patients with and 362/microL (326; 18--1162) in patients without clinical failure (P < .0001). Moreover, the proportion of patients with mean CD4+ counts < 200 microL was higher in those experiencing subsequent clinical failure (chi2: 41.11; P< .00001). Multivariate analysis showed that baseline CD4+ counts < 50 microL, HIV-RNA > 100,000 copies/mL and AIDS at baseline predicted failure; after adjusting for three-month CD4+ counts, this marker was the only one independently associated with clinical failure (HR 2.93; 95% Cl: 1.16--7.38). The three-month immunologic response is a reliable predictor of long-term clinical outcome.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Selective enhancement of gene transfer by steroid-mediated gene delivery.

The incorporation of transgenes into the host cells' nuclei is problematic using conventional nonviral gene delivery technologies. Here we describe a strategy called steroid-mediated gene delivery (SMGD), which uses steroid receptors as shuttles to facilitate the uptake of transfected DNA into the nucleus. We use glucocorticoid receptors (GRs) as a model system with which to test the principle of SMGD. To this end, we synthesized and tested several bifunctional steroid derivatives, finally focusing on a compound named DR9NP, consisting of a dexamethasone backbone linked to a psoralen moiety using a nine-atom chemical spacer. DR9NP binds to the GR in either its free or DNA-crosslinked form, inducing the translocation of the GR to the nucleus. The expression of transfected DR9NP-decorated reporter plasmids is enhanced in dividing cells: expression of steroid-decorated reporter plasmids depends on the presence of the GR, is independent of the transactivation potential of the GR, and correlates with enhanced nuclear accumulation of the transgene in GR-positive cells. The SMGD effect is also observed in cells naturally expressing GRs and is significantly increased in nondividing cell cultures. We propose that SMGD could be used as a platform for selective targeting of transgenes in nonviral somatic gene transfer.

Active Transport, Cell Nucleus↗
PubMed2001

In vitro evolution of the human immunodeficiency virus type 1 gag-protease region and maintenance of reverse transcriptase resistance following prolonged drug exposure.

We studied the human immunodeficiency virus type 1 phenotypic and genotypic profiles of a dual drug-resistant isolate (isolate 14aPost-DR) selected for zidovudine (ZDV) and lamivudine (3TC) resistance and then cultured in the presence of 3TC and a protease inhibitor: indinavir (IDV), ritonavir, or KNI-272. The IDV-treated virus was highly resistant to 3TC, ZDV, and IDV and accumulated protease mutations at positions M46I and V82F. A change from alanine to valine was observed in 4 of 10 clones in the P2 position of the p7-p1 Gag-protease cleavage site, linked to position M46I in the dominant viral quasispecies. Previous 3TC resistance did not impair the development of additional mutations in the protease and Gag-protease cleavage regions.

Drug Resistance, Microbial↗
PubMed2001

Expression level-dependent contribution of glucocorticoid receptor domains for functional interaction with STAT5.

The action of the glucocorticoid receptor (GR) on beta-casein gene transcription serves as a well-studied example of a case where the action of the GR is dependent on the activity of another transcription factor, STAT5. We have investigated the domain-requirement of the GR for this synergistic response in transfection experiments employing GR mutants and CV-1 or COS-7 cells. The results were influenced by the expression levels of the GR constructs. At low expression, STAT5-dependent transactivation by mutants of the GR DNA binding domain or N-terminal transactivation domain was impaired and the antiglucocorticoid RU486 exhibited a weak agonistic activity. When the N-terminal region of the GR was exchanged with the respective domain of the progesterone receptor, STAT5-dependent transactivation was reduced at low and high expression levels. Only at high expression levels did the GR exhibit the properties of a coactivator and enhanced STAT5 activity in the absence of a functional DNA binding domain and of GR binding sites in the proximal region of the beta-casein gene promoter. Furthermore, at high GR expression levels RU486 was nearly as efficient as dexamethasone in activating transcription via the STAT5 dependent beta-casein gene promoter. The results reconcile the controversial issue regarding the DNA binding-independent action of the GR together with STAT5 and provide evidence that the mode of action of the GR depends not only on the type of the particular promoter at which it acts but also on the concentration of the GR. GR DNA binding function appears to be mandatory for beta-casein gene expression in mammary epithelial cells, since the promoter function is completely dependent on the integrity of GR binding sites in the promoter.

Amino Acid Sequence↗
PubMed2001

Virological response in multidrug-experienced HIV-1-infected subjects failing highly active combination regimens after shifting from lamivudine to didanosine.

The aim of this study (the RESCUE trial) was to verify the effect of a shift from a lamivudine-containing to a didanosine-containing regimen on viral replication in HIV-1-infected subjects who had experienced prior treatment failure. Sixteen patients (didanosine-experienced in 14/16 cases) were consecutively enrolled: eight patients shifted from lamivudine to didanosine without other changes in their drug regimen. The other eight shifted from lamivudine to didanosine and changed one or more of their other drugs according to their physician's judgement. At the time of the regimen shift, all the subjects exhibited a high-level phenotypic resistance to both zidovudine and lamivudine with changes at codons 70-219 in 100% of cases, at codon 215 in 13 of 16 patients, and the M184V substitution in 13/16 patients. Phenotypic susceptibility to didanosine was maintained in the majority of cases (14/16) despite the high prevalence of changes at codon 184. A statistically significant decrease in viral load (P<0.005) without a significant increase in CD4 lymphocytes (P=0.514) was observed after 3 and 6 months from the introduction of the didanosine-containing regimen. These findings suggest the possibility of achieving a viral load response to didanosine-containing regimens in patients with reverse transcriptase (RT) M184V mutations who were previously treated with this drug and its possible use in salvage combinations.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Prevalence of multiple dideoxynucleoside analogue resistance (MddNR) in a multicenter cohort of HIV-1-infected Italian patients with virologic failure.

We evaluated the prevalence of both Q151M and 6-bp insert at position 69 of RT region responsible for multiple dideoxynucleoside analogue-resistant (MddNR) HIV-1 variants in 177 patients who failed to respond to combination therapy. Patients had received protease inhibitors (PI) and/or nonnucleoside reverse transcriptase inhibitors (NNRTIs) after a long-term experience with nucleoside reverse transcriptase inhibitors (NRTIs) (including zidovudine monotherapy). Two of 177 patients (1.1%) showed the specific complex of Q151M mutation, while 4 (2.3%) had the 69 6-bp insert. Mutations that belong to the 151 set in the absence of the pivotal Q151M substitution were detected in as many as 3.9% of the patients. One patient exhibited a 69S [VG] insert that has not been previously phenotypically characterized. This HIV-1 isolate had high levels of resistance to all NRTIs except stavudine. MddNR is an emerging problem after sequential therapy with this class of compounds among HIV-1-infected patients. Either didanosine (ddI) or zidovudine (ZDV) monotherapy allowed the emergence of MddNR variants containing Q151M complex. Monotherapy with ZDV and ddI or subsequent treatments with various NRTI combinations were the common background in the patients with the 69 insert. The overall prevalence of MddNR (3.4%) in Italy is comparable with that observed in several other European countries (3.4%-6.5%). These data suggest that patients failed by NRTI regimens should be analyzed for the presence of both patterns of MddNR.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Quantitative evaluation of the recombinant HIV-1 phenotype to protease inhibitors by a single-step strategy.

OBJECTIVE: To develop and optimize a fast and quantitative recombinant strategy for evaluating the HIV-1 phenotype to protease inhibitors (PI). DESIGN AND METHODS: A non-replicative HIV-1 molecular vector (designated pdelta prodelta env) capable of expressing exogenous HIV-1 protease-encoding sequences was developed in this study. The HIV-1 protease sequences were amplified from either viral isolates or plasma samples (both from 21 HIV-1-infected individuals, 19 of whom were failing different anti-HIV-1 combination treatments) and cloned in the pdelta prodelta env backbone. The HIV-1 recombinant phenotype to PI was determined directly after transfection of viral chimeric clones by measuring protease activity and calculating a percentage sensitivity index (SI%; the ratio between the results from each clone and those from a PI-sensitive reference strain). RESULTS: The SI% values obtained from the recombinant clones paralleled the IC50 results of the viral isolates and documented different degrees of resistance and cross-resistance to PI, compatible, with few exceptions, with the respective genotype. Interestingly, an inverse correlation between SI% values and the presence of primary mutations for resistance to PI (P = 0.0038 and P = 0.0414, for indinavir and ritonavir, respectively) and a difference in SI% between samples harbouring an increasing number of mutations (indinavir, P = 0.022; ritonavir, P = 0.0466) were observed. CONCLUSION: The data substantiate the reliability of the novel strategy for a fast (5 day) quantitative evaluation of HIV-1 phenotype to PI, and indicate that this method may contribute to the understanding of mechanisms of virus resistance to PI.

Chimera↗
PubMed2000

A genotypic analysis of patients receiving Zidovudine with either Lamivudine, Didanosine or Zalcitabine dual therapy using the LiPA point mutation assay to detect genotypic variation at codons 41, 69, 70, 74, 184 and 215.

BACKGROUND: The Murex-Innogenetics LiPA HIV-1 RT assay can be used to identify the presence of mutations of the reverse transcriptase gene at codons 41, 69, 70, 74, 184 and 215 of HIV-1, which have been shown to confer resistance to the nucleoside analogs Zidovudine (ZDV), Lamivudine (3TC), Didanosine (ddI) and Zalcitabine (ddC). The M184V mutation of the reverse transcriptase gene of HIV-1 has been associated with resistance to 3TC, ddC and ddI. This mutation has also been observed in patients receiving ZDV+ddC and ZDV+ddI. We used LiPA HIV-1 RT assay to identify the presence of either consensus methionine 184 or the mutant valine 184 with three groups of patients who were treated with ZDV/3TC, ZDV/ddI or ZDV/ddC combination therapy. OBJECTIVES: The aim of our study was to determine the viral genotype of patients who were considered to be failing therapy, by two ways: using sequencing and LiPA assays. In particular we were interested in establishing a possible correlation between these methods. STUDY DESIGN: The study group consisted of a consecutive series of 33 patients with a treatment failure, 18 of whom received ZDV+3TC therapy, seven received ZDV+ddI and eight received ZDV+ddC therapy. We also examined a small cohort of seven seroconverters. RESULTS: The M184V mutation was observed in 47.0% of patients receiving ZDV+3TC combination therapy but was not observed in either patient group receiving either ddI or ddC as co-therapy with ZDV. There was no evidence of the L74V mutation in our study group in either the ZDV/ddI or ZDV/ddC combination therapy group. We found the frequency of the K70R mutation to be higher in patients treated with ZDV/ddI (P=0.033) or ZDV/ddC (P=0.3) when compared with patients treated with ZDV/3TC. CONCLUSION: The LiPA assay allowed for the rapid detection of wild type and amino acid variations at key positions conferring resistance to the most used antiviral RT inhibitors. This represented a rapid, quite sensitive, and simple genotyping test. For these reasons the LiPA assay proved to be useful in studying genetic resistance in large screenings, when key RT mutations could be useful in guiding an effective HIV-1 suppressing regimen.

Anti-HIV Agents↗
PubMed2000

Susceptibility to PNU-140690 (Tipranavir) of human immunodeficiency virus type 1 isolates derived from patients with multidrug resistance to other protease inhibitors.

In our study we examined the anti-human immunodeficiency virus type 1 (anti-HIV-1) activity of a novel HIV-1 protease inhibitor, PNU-140690 (tipranavir), against patient-derived isolates resistant to multiple other protease inhibitors (PIs). The aim of our experiments was to investigate the genotypes and the in vitro phenotypes of drug resistance of PNU-140690. We carried out drug susceptibility tests with peripheral blood mononuclear cells and a fixed amount of infectious virus (1,000 50% tissue culture infective doses) to determine the 50% inhibitory concentration (IC(50)) and IC(90), PCR assays for the detection of drug resistance mutations in RNA in plasma, and direct sequencing of PCR products. Phenotypic resistance to PIs was invariably related to genotypic mutations. The substitutions among the amino acid residues of the protease included L10I, K20R, L24I, M36I, N37D, G48V, I54V, L63P, I64V, A71V, V77I, V82A, I84V, and L90M. Isolates from all of the patients had developed a maximal degree of resistance to indinavir, ritonavir, and nelfinavir (IC(50)s, >0.1 microM). We also compared these mutations with the amino acid changes previously described in association with in vivo tipranavir administration. The mutations included the following: I15V, E35D, N37D, R41K, D60E, and A71T. Infections with IIIB, 14aPre, and N70 were inhibited by an average drug IC(90) of 0.18 +/- 0.02 microM in multiple experiments. The average mean +/- standard error of mean IC(90) for the entire group of multidrug-resistant isolates derived from the mean values for two culture wells with p24 antigen supernatant appeared to be 0.619 +/- 0.055 microM (range, 0.31 to 0.86 microM). Tipranavir retained a sustained antiviral activity against PI-MDR clinical isolates and might be useful in combination regimens with other antiretroviral agents for patients who have already failed other PI-containing therapies.

Anti-HIV Agents↗
PubMed2000

Combination of CCR5 and CXCR4 inhibitors in therapy of human immunodeficiency virus type 1 infection: in vitro studies of mixed virus infections.

We studied the combined anti-human immunodeficiency virus type 1 (HIV-1) effects of a derivative of stroma-derived factor 1beta (SDF-1beta), Met-SDF-1beta, and a modified form of RANTES, aminooxypentane (AOP)-RANTES. The antiviral agents were tested singly or in combination at 95 and 99% virus inhibitory concentrations. Clinical R5 and X4 HIV-1 isolates were used. AOP-RANTES inhibited R5 but not X4 viruses, whereas Met-SDF-1beta had the opposite effect. Combinations of these compounds inhibited mixed infections with R5 and X4 viruses (95 to 99%), whereas single drugs were less inhibitory (32 to 61%). Combinations of R5 and X4 inhibitors are promising and deserve further evaluation.

Amino Acid Sequence↗