Search PubMed⌕ Search

Biomedical subjects

G Leone

Publications and source records attributed to G Leone.

At least 127 records · Page 7Linked to original sources
PubMed1999

The risk of recurrent deep venous thrombosis among heterozygous carriers of both factor V Leiden and the G20210A prothrombin mutation.

BACKGROUND: Point mutations in the factor V gene (factor V Leiden) and the prothrombin gene (the substitution of A for G at position 20210) are the most common causes of inherited thrombophilia. Whether or not factor V Leiden increases the risk of recurrent deep venous thrombosis is controversial, and there is no information on the risk of recurrence among carriers of both mutations. METHODS: We studied a retrospective cohort of 624 patients who were referred for a first episode of deep venous thrombosis. After excluding 212 patients with other inherited or acquired causes of thrombophilia, we compared 112 patients who were heterozygous carriers of factor V Leiden with 17 patients who were heterozygous for both factor V Leiden and the prothrombin mutation and 283 patients who had neither mutation. The relative risk of recurrent deep venous thrombosis was calculated with use of a proportional-hazards model. RESULTS: Patients who were heterozygous for factor V Leiden alone had a risk of recurrent deep venous thrombosis that was similar to that among patients who had neither mutation (relative risk, 1.1; 95 percent confidence interval, 0.7 to 1.6; P=0.76). In contrast, patients who were heterozygous for both factor V Leiden and the prothrombin mutation had a higher risk of recurrent thrombosis than did carriers of factor V Leiden alone (relative risk, 2.6; 95 percent confidence interval, 1.3 to 5.1; P=0.002). When the analysis was restricted to patients with spontaneous recurrences (i.e., ones that occurred in the absence of transient risk factors for venous thrombosis), the risk among carriers of both mutations, as compared with carriers of factor V Leiden alone, remained high (relative risk, 3.7; 95 percent confidence interval, 1.7 to 7.7; P<0.001), particularly if the first event had also been spontaneous (relative risk, 5.4; 95 percent confidence interval, 2.0 to 14.1; P<0.001). In contrast, the risk of recurrence in the presence of transient risk factors was similar among carriers of both mutations and carriers of factor V Leiden alone. CONCLUSIONS: The risk of recurrent deep venous thrombosis is similar among carriers of factor V Leiden and patients without this mutation. Carriers of both factor V Leiden and the G20210A prothrombin mutation have an increased risk of recurrent deep venous thrombosis after a first episode and are candidates for lifelong anticoagulation.

Adolescent↗
PubMed1999

Elderly aggressive-histology non-Hodgkin's lymphoma: first-line VNCOP-B regimen experience on 350 patients.

Age is a risk factor and a prognostic parameter in elderly aggressive-histology non-Hodgkin's lymphoma (NHL) patients. Several adapted chemotherapeutic regimens have recently been designed and tested on elderly patients. Several of these trials have shown that older aggressive-histology NHL patients can benefit from specific and adequate treatment capable of curing a percentage of these patients. Between January 1992 and September 1997, 350 previously untreated aggressive-histology NHL patients greater than 60 years of age were treated with a combination therapy including cyclophosphamide, mitoxantrone, vincristine, etoposide, bleomycin, and prednisone (VNCOP-B). Complete remission (CR) was achieved by 202 (58%) patients and partial remission (PR) by 87 (25%), whereas the remaining 61 (17%) patients were nonresponders. The overall response rate (CR + PR) was 83%. Clinical and hematologic toxicities were modest, because 71% of the patients received granulocyte colony-stimulating factor (G-CSF). The CR rates for the three age groups (60 to 69, 70 to 79, and >/=80 years) were similar: 61%, 59%, and 56%, respectively. At 5 years, the relapse-free survival rate was 65%, the overall survival rate was 49%, and the failure-free survival rate was 33%. In the multivariate analysis, prognostic factors associated with longer survival or longer relapse-free survival turned out to be localized disease stage (P =.001) and good performance status (P =.0002). Application of the International Prognostic Factor Index was significantly associated with outcome (P =.001). These data confirm on a large cohort of patients that the VNCOP-B regimen is effective in inducing good CR and relapse-free survival rates with only moderate toxic effects in elderly aggressive-histology NHL.

Aged↗
PubMed1999

Induction of CD69 antigen on normal CD4+ and CD8+ lymphocyte subsets and its relationship with the phenotype of responding T-cells.

We evaluated phenotype and apoptotic status of normal CD4+CD69+ and CD8+CD69+ peripheral blood T-lymphocytes after short-term challenge with escalating concentrations of phytohemagglutinin (PHA). The frequency of CD69-coexpressing CD4+ and CD8+ T-cells and CD69 staining intensity increased following T-cell mitogenic stimulation; these changes were proportional to PHA concentration in culture medium. A considerable fraction of lymphocytes underwent blast transformation, displaying increased forward and side scatter signals. Interestingly enough, PHA-responsive T-cells exhibited a predominantly CD25negCD38negTCRalphabetapos phenotype; APO-1/Fas antigen (CD95) could be detected on a minority of activated CD69+ T-cells. A considerable proportion of CD69+ lymphocytes expressed intracellular perforin; in addition, an average 16+/-6% CD69+ T-lymphocytes were apoptotic after 4 h of stimulation, as evaluated by 7-amino-actinomycin-D staining and by annexin-V binding. CD69+ activated lymphocytes comprise phenotypically heterogeneous cell subpopulations potentially devoted to diverse immunological functions, i.e., proliferation, apoptosis, or cell cytotoxicity; moreover, our findings indicate that CD69 expression is proportional to the intensity of the activating stimulus and that the capacity to upregulate CD69 antigen following short-term mitogenic challenge may be restricted to unactivated CD38negCD25negTCRalphabetapos T-lymphocytes.

Annexin A5↗
PubMed1999

Collaborative role of E2F transcriptional activity and G1 cyclindependent kinase activity in the induction of S phase.

A considerable body of evidence points to a role for both cyclin E/cyclin-dependent kinase (cdk)2 activity and E2F transcription activity in the induction of S phase. We show that overexpression of cyclin E/cdk2 in quiescent cells induces S phase, that this coincides with an induction of E2F activity, and that coexpression of E2F enhances the cyclin E/cdk2-mediated induction of S phase. Likewise, E2F overexpression can induce S phase and does so in the apparent absence of cyclin E/cdk2 activity. In addition, although the inhibition of cyclin E/cdk2 activity blocks the induction of S phase after growth stimulation of normal mouse embryo fibroblasts, inhibition of cyclin E/cdk2 does not block S phase induction in Rb-/- cells where E2F activity is deregulated. These results point to the important roles for E2F and cyclin E/cdk2 in the induction of S phase. Moreover, the nature of the E2F targets and the suspected targets for cyclin E/cdk2 suggests a potential molecular mechanism for the collaborative action of cyclin E/cdk2 and E2F in the induction of S phase.

Animals↗
PubMed1999

RANTES and MCP-1 chemokine plasma levels in chronic renal transplant dysfunction and chronic renal failure.

OBJECTIVES: Procedures to diagnose renal allograft rejection depend on detection of graft dysfunction due to the presence of mononuclear leukocytic infiltrates. DESIGN AND METHODS: In our study, we pursued an immunodiagnostic approach utilizing an ELISA method on plasma samples to monitor patients waiting to undergo transplantation in order to evidence prognostic developments in renal transplantation and, at least, to diagnose renal chronic transplant dysfunction. We analyzed blood levels of two chemokines, RANTES and MCP-1, which are normally overexpressed locally in renal chronic rejection. RESULTS: Our results showed that patients affected by chronic renal failure (and waiting for kidney transplant), as well as kidney-grafted patients affected by chronic transplant dysfunction, had plasma levels of RANTES significantly higher than those of controls (patients without acute or chronic pathologies). CONCLUSIONS: Our data suggest a simple method to evaluate the plasmatic presence of RANTES, which could be involved in longterm kidney graft failure.

Adolescent↗
PubMed1999

Expansion of granulocyte colony-stimulating factor/chemotherapy-mobilized CD34+ hematopoietic progenitors: role of granulocyte-macrophage colony-stimulating factor/erythropoietin hybrid protein (MEN11303) and interleukin-15.

Ex vivo stroma-free static liquid cultures of granulocyte colony-stimulating factor (G-CSF)/chemotherapy-mobilized CD34+ cells were established from patients with epithelial solid tumors. Different culture conditions were generated by adding G-CSF, granulocyte-macrophage colony-stimulating factor (GM-CSF), Flt3 ligand (Flt3), megakaryocyte growth and development factor (Peg-rHuMGDF), GM-CSF/erythropoietin (EPO) hybrid protein (MEN11303), and interleukin-15 (IL-15) to the basic stem cell factor (SCF) + interleukin-3 (IL-3) + EPO combination. This study showed that, among the nine different combinations tested in our 5% autologous plasma-containing cultures, only those containing IL-3/SCF/Flt3/MEN11303 and IL-3/SCF/Flt3/MEN11303/IL-15 significantly expanded colony-forming unit granulocyte-macrophage (CFU-GM), burst-forming unit erythroid (BFU-E), long-term culture-initiating cells (LTC-IC), CD34+, and CD34+/CD38- cells after 14 days of culture. Particularly, the addition of IL-15 to IL-3/SCF/Flt3/MEN11303 combination produced a significant increase of LTC-IC, with an average 26-fold amplification as compared to input cells, without any detrimental effect on CFU-GM and BFU-E expansion. This combination also produced a statistically significant 3.6-fold expansion of primitive CD34+/CD38- cells. Moreover, this study confirms the previously described erythropoietic effect of MEN11303, which, in our experience, was the only factor capable of expanding BFU-E. Compared to equimolar concentrations of GM-CSF and EPO, MEN11303 hybrid protein showed a significantly higher capacity of expanding CFU-GM, BFU-E, LTC-IC, CD34+, and CD34+/CD38- cells when these cytokines were tested in combination with IL-3/SCF/Flt3. These cultures indicated that Peg-rHuMGDF addition to IL-3/SCF/EPO/Flt3 does not affect CFU-GM and BFU-E expansion but, unlike G-CSF or GM-CSF, it does not decrease the ability of Flt3 to expand primitive LTC-IC. These studies indicate that, starting from G-CSF/chemotherapy-mobilized CD34+ cells, concomitant expansion of primitive LTC-IC, CFU-GM, BFU-E, CD34+, and CD34+/CD38- cells is feasible in simple stroma-free static liquid cultures, provided IL-3/SCF/Flt3/MEN11303/IL-15 combination is used as expanding cocktail in the presence of 5% autologous plasma.

Adolescent↗
PubMed1999

Ras enhances Myc protein stability.

Various experiments have demonstrated a collaborative action of Myc and Ras, both in normal cell growth control as well as during oncogenesis. We now show that Ras enhances the accumulation of Myc activity by stabilizing the Myc protein. Whereas Myc has a very short half-life when produced in the absence of mitogenic signals, due to degradation by the 26S proteasome, the half-life of Myc increases markedly in growth-stimulated cells. This stabilization is dependent on the Ras/Raf/MAPK pathway and is not augmented by proteasome inhibition, suggesting that Ras inhibits the proteasome-dependent degradation of Myc. We propose that one aspect of Myc-Ras collaboration is an ability of Ras to enhance the accumulation of transcriptionally active Myc protein.

Animals↗
PubMed1999

Modulation of VLA-4 and L-selectin expression on normal CD34+ cells during mobilization with G-CSF.

We have evaluated the immunophenotype, functional activity and clonogenic potential of CD34+ cells from peripheral blood (PB) of normal donors before and after 4 and 6 days of G-CSF administration. The percentage and absolute number of CD34+ cells significantly increased at days 4 and 6 of G-CSF administration, compared to the steady-state level (P < 0.0001). Two-colour fluorescence analysis showed, at days 4 and 6, a lower proportion of CD34+/c-kit+ compared to the steady-state level (P < 0.0001), but a similar expression of CD13, CD33, CD38, HLA-DR and Thy-1 antigens on CD34+ cells. The expression of adhesion molecules on CD34+ cells revealed a significant reduction of CD11a (P = 0.009), CD18, CD49d and CD62L (P < 0.0001) at days 4 and 6, compared to the baseline level. Three-colour staining showed a reduction of the more immature compartment (34+/DR-/13-) and an increase of the more differentiated compartment (34+/DR+/13+). Downregulation of VLA-4 during mobilisation was seen almost exclusively on more committed cells (34+/13+); downregulation of CD62L, on the contrary, was observed on both early progenitors (34+/13-) and more committed cells (34+/13+). The expression of 34+/VLA-4+ decreased on both c-kit+ and c-kit- cells, while the expression of 34+/62L+ decreased on the c-kit+ cells only. In vivo administration of G-CSF reduced the adherence capacity of CD34+ cells to normal BM stroma; in vitro incubation with SCF or IL-3 enhanced the expression of CD49d on CD34+ cells, while GM-CSF reduced the expression of CD62L. SCF was the only cytokine able to induce a significant increase of CD34+ cell adherence to preformed stroma. Pre-incubation with the blocking beta2 integrin monoclonal antibody caused a reduction of CD34+ cell adherence. In conclusion, the decrease of CD49d expression on mobilized CD34+ cells correlates with a poor adhesion to BM stroma; CD34+ cells incubated in vitro with SCF showed, conversely, a higher expression of CD49d and a greater adherence capacity on normal preformed stroma.

Antigens, CD↗
PubMed1999

Optimal timing of G-CSF administration after CD34+ immunoselected peripheral blood progenitor cell transplantation.

G-CSF accelerates neutrophil recovery after autologous peripheral blood progenitor cell transplantation (aPBPCT), although the optimal timing for its administration is currently unknown. In order to establish the role and the optimal timing of administration of G-CSF after immunoselected CD34+ aPBPCT, we analyzed the data from 21 consecutive patients affected by haematological malignancies. Patients were randomized into three groups according to G-CSF administration after transplantation: day +1 (group B); day +7 (group C) or no G-CSF (group A). Serum G-CSF level was evaluated until engraftment. The CD34+ cell dose reinfused was similar (P = 0.48). G-CSF significantly reduced time to recovery of PMN >0.5 x 10(9)/l (11 vs 14 vs 20.5 days) (P= 0.00046); >1.0 x 10(9)/l (12 vs 15 vs 22) (P = 0.001). No difference was observed in the number of days with PMN <0.1 x 10(9)/l (5.5 vs 7 vs 8 days). Platelet count >50 x 10(9)/l and >100 x 10(9)/l, reticulocytes >1%, length of hospitalization, non-prophylactic antibiotic therapy, fever, incidence of sepsis and transfusion support did not differ. Early or delayed G-CSF after immunoselected CD34+ aPBPCT significantly accelerated PMN recovery but did not reduce the amount of supportive treatment or the duration of hospitalization. Delaying the initiation of G-CSF did not reduce the length of treatment (11.5 vs 12 days). Early or delayed G-CSF administration resulted in G-CSF peak serum levels 7 (early)-12 (delayed)-fold greater than an endogenous response to neutropenia.

Adolescent↗
PubMed1999

Monitoring of CD34+ cells during leukapheresis allows a single, successful collection of hemopoietic progenitors in patients with low numbers of circulating stem cells.

We have studied a total of 188 patients with hematological malignancies, submitted to mobilization therapy with G-CSF associated or not with chemotherapy in order to: (1) establish the lower limit of circulating progenitor cells that allows the collection of 2 x 10(6) CD34+ cells/kg by a single leukapheresis, utilizing the instrument set on standard parameters; (2) evaluate whether the number and quality of CD34+ cells collected remain stable during leukapheresis; and (3) collect a sufficient number of circulating CD34+ cells by a single procedure in patients in whom such an approach would have been insufficient to reach the target with the instrument set on standard parameters. The retrospective analysis conducted in 85 patients showed that 19 circulating CD34+ cells/microl represented the cut-off number capable of discriminating between patients who will require one or more apheresis to collect 2 x 10(6) CD34+ cells/kg. The validity of this value was prospectively confirmed in 70 subsequent patients. Based on in vitro results that showed the stability in the number of CD34+ cells, the proportion of different CD34+ cell subpopulations and the clonogenic capacity of the stem cell compartment during leukapheresis both in the blood of the patients and in samples taken directly from the instrument, we have adapted the blood volume to be processed in 33 patients with <19 PB CD34+ cells/microl. Stem cell collection was monitored during the leukapheresis and the procedure was prolonged for a time period estimated to be sufficient to reach the target number of CD34+ cells with a single procedure. The median increment of the total blood volume processed, calculated from the volume set automatically by the instrument was 25.2%, with a median of 3.3-fold total blood volume processed. In all cases, a sufficient CD34+ cell collection was completed in a single procedure. After autograft, the pattern of blood reconstitution was similar to that of all the other patients.

Adolescent↗
PubMed1999

Inappropriate antidiuretic hormone secretion after high-dose thiotepa.

High-dose thiotepa has been successfully included in a variety of conditioning regimens for stem cell transplantation in hematological and solid neoplasms. Toxicity of high-dose thiotepa mainly manifests as profound myeloablation and some degree of liver damage. We report a case of inappropriate secretion of antidiuretic hormone (SIADH) in a patient with primary CNS lymphoma who underwent therapy with high-dose thiotepa.

Adult↗
PubMed1999

Prevalence of mild hyperhomocysteinaemia and association with thrombophilic genotypes (factor V Leiden and prothrombin G20210A) in Italian patients with venous thromboembolic disease.

Mild hyperhomocysteinaemia is an established risk factor for deep vein thrombosis (DVT); few data concerning its potential interaction with thrombophilic genotypes are available at the present time. We investigated 121 thrombosis-free individuals and 111 patients with at least one objectively confirmed episode of DVT. A thrombophilic condition (deficiency in antithrombin, protein C and S, factor V Leiden, prothrombin G20210A) was detected in 25.2% of the patients; mutant factor V or prothrombin genotypes were present in 6.6% of the controls. Hyperhomocysteinaemia was found in 14.4% of patients and 3. 3% of the controls, with a 3.7-fold increase in risk for DVT (95% CI 1.1-12.3). Adoption of different cut-off levels for definition of hyperhomocysteinaemia did not substantially change the magnitude of the risk. Carriership of both hyperhomocysteinaemia and factor V Leiden or prothrombin G20210A was detected in 2.7% of patients for each combination and in none of the controls. An approximate estimate of 30-fold increased risk in carriers of both hyperhomocysteinaemia and factor V Leiden and 50-fold increased risk in carriers of both hyperhomocysteinaemia and prothrombin G20210A was calculated, suggesting a synergistic interaction between hyperhomocysteinaemia and such thrombophilic genotypes. Yet statistical analysis is highly unstable due to the small number of individuals with combined defects. Further investigations on large series of patients are needed.

Adolescent↗