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Biomedical subjects

G Leone

Publications and source records attributed to G Leone.

At least 19 recordsLinked to original sources
PubMed1995

E2F-1 accumulation bypasses a G1 arrest resulting from the inhibition of G1 cyclin-dependent kinase activity.

Numerous experiments have defined a critical role for the G1 cyclins and associated kinases in allowing a normal progression of cells from a quiescent state, through G1, and into S phase. We now demonstrate that G1 cyclin-dependent kinase activity is critical for the accumulation of E2F activity late in G1. Moreover, E2F-1 overexpression can overcome a G1 arrest caused by the inhibition of G1 cyclin-dependent kinase activity, consistent with E2F activation being an important consequence of the action of G1 cyclins. E2F-1 also overcomes a G1 block caused by gamma irradiation and leads to an apparent complete replication of the cellular genome and entry into mitosis. This E2F-1-mediated induction of S phase and mitosis is not accompanied by the rise in either cyclin D-associated kinase activity or cdk2 activity that is normally observed during the G1 phase of the cell cycle. We conclude that one key function for G1 cyclin-dependent kinase activity is the activation of E2F-1, that the accumulation of E2F activity may be sufficient to allow initiation and completion of S phase, but that additional events, including G1 cyclin kinase activity, are likely necessary for a normal proliferative event.

Blotting, Western↗
PubMed1995

Effect of all-trans retinoic acid on procoagulant and fibrinolytic activities of cultured blast cells from patients with acute promyelocytic leukemia.

The mechanisms underlying acute promyelocytic leukemia (APL) coagulopathy and its reversal by administration of all-trans retinoic acid (ATRA) have been investigated. Bone marrow promyelocytic blasts from nine patients with APL were cultured with or without ATRA 1 mumol/L. Cultured blasts (days 0, 3, 6, and 9) were washed, resuspended in phosphate buffer, lysed by freezing and thawing, and then assayed for procoagulant activity (PCA), elastase activity, tissue factor (TF) antigen, tissue-type plasminogen activator (t-PA) antigen and urokinase-type plasminogen activator (u-PA) antigen. PCA was determined by a recalcification assay. Elastase was measured by an amidolytic assay (S-2484). TF, t-PA, and u-PA antigens were measured by an enzyme-linked immunosorbent assay (ELISA). Malignant promyelocytes isolated from the patients had increased levels of PCA and TF as compared with the control polymorphonucleates, and low levels of elastase, t-PA, and u-PA; the patient blast PCA level was significantly related to the degree of hypofibrinogenemia. In this system, blast PCA depended on the tissue factor and was significantly correlated to the TF antigen values. In the cultures without ATRA, PCA, TF, and u-PA progressively increased, whereas elastase and t-PA levels remained essentially unchanged. In the presence of ATRA, all parameters (except u-PA) decreased during the culture time. Thus, a major role of the promyelocytic blast cell PCA in the pathogenesis of M3-related coagulopathy is suggested; the ATRA effect on coagulopathy seems mainly mediated by a downregulation of the PCA.

Adolescent↗
PubMed1995

Quercetin inhibits the growth of leukemic progenitors and induces the expression of transforming growth factor-beta 1 in these cells.

We previously showed that quercetin (3,3',4',5,7 pentahydroxyflavone) inhibits in a dose-dependent manner the growth of acute leukemias and is able to enhance the antiproliferative activity of cytosine arabinoside. We show here that quercetin inhibits the clonogenic activity of 20 of 22 acute leukemias (AL; 4 M1-AML, 3 M2-AML, 2 M3-AML, 3 M4-AML, 3 M5-AML, and 7 ALL). In the present report, we show that the induction of transforming growth factor-beta 1 (TGF-beta 1) in leukemic blasts is one of the growth-inhibitory mechanisms of quercetin in these cells. This observation was supported by the following data. (1) Quercetin-sensitive leukemic blasts, when treated with quercetin, secrete large amounts of TGF-beta 1 in the medium and show positivity for TGF-beta 1-immunoreactive material in the cytoplasm. (2) At a concentration of 8 mumol/L, antisense TGF-beta 1 oligonucleotides prevent the growth-inhibitory action of quercetin. (3) Anti-TGF-beta 1 neutralizing monoclonal antibodies can prevent almost completely the growth-inhibitory activity of quercetin. The analysis of quercetin-resistant cases confirmed as well the central role of TGF-beta 1 in the growth-inhibitory activity of quercetin. In conclusion, quercetin can act as a cytostatic agent for leukemic cells by modulating the production of TGF-beta 1.

Bone Marrow↗
PubMed1995

Microangiopathic hemolytic anemia and severe thrombocytopenia in Brucella infection.

A case of Brucella septicemia presenting at the onset as a severe microangiopathic hemolytic anemia with coexisting dramatic hemorrhagic syndrome (severe epistaxis, gross hematuria, and skin purpura) is reported. A hemogram showed severe thrombocytopenia, anemia, and leukopenia. Bone marrow morphology showed the typical features associated with Brucella infection: numerous histiocytes with signs of activation, multiple granulomata, giant cells, and hemophagocytosis. After appropriate antimicrobial therapy, the clinical and hematological status of the patient improved, and he is alive and well 1 year later with disappearance of all hematological abnormalities.

Adult↗
PubMed1995

Intrathecal chemotherapy for treatment of overt meningeal leukemia: comparison between intraventricular and traditional intralumbar route.

BACKGROUND: Despite advances in the treatment of acute lymphoblastic leukemia (ALL), overt meningeal leukemia remains a dire condition. The role of intraventricular chemotherapy (IVC) in its treatment is still a matter for debate. Data suggesting benefit from it have been countered by statements of concern regarding the potential complications associated with its use. This report details our results from using IVC. PATIENTS AND METHODS: We compared two groups of adult patients with ALL at their first meningeal involvement. Twelve of them were submitted to ILC and 9 to IVC. RESULTS: Our data showed that IVC yielded a higher rate of complete response (88% vs. 33%) and a lower incidence of second CNS relapse than did ILC (none vs. 50%). Even though there were more long-term disease-free survivors (33% vs. 8%) among the IVC patients, the difference in median event-free survival was not significant (120 vs. 80 weeks; p = 0.66). IVC was associated with a longer overall survival (p = 0.005) and CNS remission time (p = 0.046). Two cases refractory to ILC were later fully responsive to IVC. There were 22% device-related and 11% drug-related complications. CONCLUSIONS: The results are promising, but the small series does not allow for any definite conclusion. In our opinion, the hazards inherent in the placement and operation of the device do not outweight the benefits of IVC for the treatment of overt meningeal leukemia and should not preclude its use. Accurate neurosurgical technique, meticulous care in drug administration and experience with this form of therapy can all contribute to minimizing complications so that full advantage can be taken of IVC's potential.

Adolescent↗
PubMed1995

Independence of bilateral symmetry detection from a gravitational reference frame.

Data were collected during three orbital flights aboard the Russian MIR space station from eight cosmonauts tested on a bilateral symmetry detection task. It is known that on earth subjects' performance is significantly superior for a vertical or horizontal than for an obliquely oriented axis of symmetry, giving a so-called oblique effect. The present results show that this oblique effect did not disappear in microgravity. They confirm that the detection of visual symmetry is not tied to a gravitational reference frame. An unexpected result of the experiments was that practice reduced the reaction time for detection of asymmetrical patterns below that for symmetrical patterns. This result suggests the presence of two separate detection processes. The detection of symmetry, being useful for the efficient encoding of visual information, is well developed in naive subjects. Extensive practice on a symmetry-detection task, however, increases the efficacy of the asymmetry-detection process.

Adult↗
PubMed1994

Autologous stem cell transplantation: release of early and late acting growth factors relates with hematopoietic ablation and recovery.

We have monitored the serum concentrations of hematopoietic growth factors (HGFs; ie, stem cell factor [SCF], leukemia inhibitory factor [LIF], interleukin-3 [IL-3], IL-6, IL-8, and granulocyte colony-stimulating factor [G-CSF]) in 15 lymphoma/leukemia and 6 ovarian cancer patients undergoing autologous bone marrow (BM) or peripheral blood (PB) stem cell transplantation (SCT). Thus, the analysis was performed during and after high-dose chemotherapy (from day -6 to day -1), at the time of SCT (day 0), and thereafter (through day +17). Despite the heterogeneity of these patients and their conditioning regimens, a consistent kinetic pattern was observed for all analyzed cytokines. Particularly, (1) SCF serum concentration did not significantly fluctuate. (2) High levels of LIF (approximately 250 to 450 pg/mL) before chemotherapy rapidly declined to markedly lower concentrations (approximately 10 ng/mL) starting from day -1 through day +17; (3) conversely, IL-3 level was low before treatment, sharply increased during chemotherapy, and rapidly returned to base-line level after SCT. Hypothetically, the sharp LIF decrease and IL-3 increase during chemotherapy may underlie the induction of stem cell cycling and differentiation caused by hematopoietic ablation. Furthermore, (4) IL-6 concentration was low before and immediately after chemotherapy, but increased starting from day +5, peaked at day +6 through 9 and then declined to baseline level from day +10 onward; (5) a strictly similar pattern was consistently observed for both G-CSF and IL-8 levels, in agreement with our previous studies. It is relevant that peak IL-6, G-CSF, and IL-8 concentrations were directly correlated to peak neutrophil numbers in the recovery phase, thus suggesting an important role for these cytokines in granulocyte rescue; in line with this interpretation, hematologic patients undergoing PBSCT (10 of 15) exhibited higher peaks of IL-6, G-CSF, and IL-8 and a more pronounced increase of neutrophil/platelet number than did hematologic cases undergoing BMSCT (5 of 15). Altogether, these studies indicate a coordinate pattern of cytokine release during hematopoietic ablation/recovery after chemotherapy and autologous SCT, the fluctuations of LIF and IL-3 levels during chemotherapy are seemingly related to stem cell recruitment, whereas the post-SCT increase of IL-6, G-CSF, and IL-8 may underlie the neutrophil recovery.

Adolescent↗
PubMed1994

Inhibition of hematopoiesis by competitive binding of transcription factor PU.1.

Transcription factors have been shown to play a role as "master switch" factors in the programming of hematopoietic cell commitment and differentiation. PU.1 is a hematopoietic-specific member of the Ets family of transcription factors. In human bone marrow CD34-enriched progenitor cells, PU.1 expression was upregulated during the early phases of granulocytic/monocytic differentiation, preceding expression of its target genes encoding CD11b and the macrophage-colony-stimulating factor receptor, whereas PU.1 was expressed at stable levels throughout erythroid differentiation. To study PU.1 function, we synthesized double-stranded phosphorothioate oligonucleotides containing a characterized PU.1 site and demonstrated their ability to specifically compete for PU.1 DNA binding. When added to CD34+ cells in vitro, wild-type PU.1-binding oligonucleotides significantly blocked hematopoietic colony formation, whereas mutated PU.1 oligonucleotides which no longer bind PU.1 had no specific inhibitory effect. These results demonstrate that PU.1 is developmentally upregulated during normal human myelopoiesis and that the function of PU.1 is critical for the development of in vitro hematopoiesis.

Antigens, CD↗
PubMed1994

Binding of reovirus to receptor leads to conformational changes in viral capsid proteins that are reversible upon virus detachment.

A conformational change was detected in reovirus upon its attachment to mouse L fibroblasts. Specifically, the capsid proteins of cell-bound virions became more resistant to pepsin digestion. Similar observations were made using glutaraldehyde-fixed cells or plasma membranes instead of live cells, indicating that virus internalization was not necessary for this effect. This conformational change was totally reversible, since bound virions reverted back to the pepsin-sensitive state upon release from the cell surface. Not unexpectedly, a conformational change was also detected in the reovirus cell attachment protein sigma 1 when it alone bound to cells. The alteration was mapped, by deletion mutagenesis, to a region proximal to the N-terminal (virion-anchoring) end of the protein and was also found to be reversible. Structural changes in sigma 1 were also detectable following its interaction with sialic acid (conjugated to bovine serum albumin) shown previously to the minimal receptor determinant recognized by reovirus. These results suggest that upon cell attachment, a signal is transmitted from the C-terminal receptor-binding region of sigma 1 to the N terminus in a ripple-like progression that eventually leads to conformational changes in the other reovirus capsid proteins. An altered conformational state may be necessary for subsequent viral entry and programmed disassembly of viral capsids inside susceptible cells.

Animals↗
PubMed1994

Prevalence of obesity in young adults with acute lymphoblastic leukemia.

We studied the hormonal pattern of nine patients with acute lymphoblastic leukemia. The patients were treated with standard therapeutic regimens. They were overweight by a mean of 52% at the end of the consolidation treatment, and this persisted after a follow-up of 2 years. The only endocrine alteration observed was a moderate decrease in serum testosterone levels in male patients. The other parameters studied were in the normal range. We conclude that prolonged treatment with high doses of corticosteroids, which have a depressive effect on metabolism, was responsible for the obesity.

Adolescent↗
PubMed1994

Antithrombin III infusion suppresses the hypercoagulable state in adult acute lymphoblastic leukaemia patients treated with a low dose of Escherichia coli L-asparaginase. A GIMEMA study.

Thrombotic events have been reported in acute lymphoblastic leukaemia patients, especially during or after L-asparaginase administration. A so-called L-asparaginase associated coagulopathy has been well recognized, being characterized by a hypercoagulable state (decrease of antithrombin III, plasminogen, protein C, protein S and increase of prothrombin fragment F1 + 2, thrombin-antithrombin complexes and fibrinopeptide A). The aim of this study was to determine whether the supplementation of antithrombin III (AT-III) concentrates could improve the L-asparaginase associated coagulopathy, thereby blocking the activation of the haemostatic system. In 25 adult patients with acute lymphoblastic leukaemia (M 19, F6, mean age 34 years) antithrombin III (AT-III) concentrates were administered at daily doses of 50 U/kg for 10 consecutive days from the beginning of L-asparaginase therapy (6,000 U/m2/day s.c. for 7 days), given according to the GIMEMA ALL 0288 trial. A marked increase of antithrombin III was recorded on days IV-VIII-XI (P < 0.001). No changes in protein C, protein S, plasminogen, alpha 2-antiplasmin, factor VII and platelet count were observed and there was no increase in markers of hypercoagulability. There was no evidence of disseminated intravascular coagulation. In conclusion, AT-III concentrate supplementation during L-asparaginase therapy, by the achievement of high levels of antithrombin III, is associated with a lack of activation of the haemostatic system and appears to overcome the complex coagulopathy associated with L-asparaginase.

Adolescent↗
PubMed1994

Campodimele study: blood pressure and heart rate pattern in clinically healthy elderly subjects.

Noninvasive ambulatory blood pressure (BP) monitoring is a developing method in clinical practice. Its interpretation needs reference standards stratified by age and gender. This study addresses ambulatory BP monitoring in elderly people with the purpose of quantifying the discrete and periodic variability of BP pattern over a 24-h period. The ABPM was performed in 92 clinically healthy subjects (45 men and 47 women) ranging in age from 76 to 102 years. The results refer to the time-qualified mean values with their dispersion, to the circadian rhythm with its parameters, and to the daily baric impact (BI) with its variability. The conclusion is drawn that BP preserves its nychtohemeral variability and circadian rhythmicity despite old age. The daily BP mean level and BI in older people in good health are comparable with those of young subjects, suggesting that humans surviving into old age are characterized by a eugenic control of their pressure regimen.

Aged↗
PubMed1994

Aggressive chemotherapy for acute leukemia relapsed after transplantation.

Bone marrow transplantation procedure has emerged as an effective treatment for hematological malignancies. However, recurrence of leukemia is still the major cause of treatment failure. Subsequent treatment in this category of patients, generally considered incurable, has not been yet standardized. At our institution, 13 patients, 7 with acute non lymphoid leukemia (ANLL) and 6 with acute lymphoid leukemia (ALL), were treated at relapse after bone marrow transplantation either autologous or allogeneic (AuBMT 8, ABMT 4) performed in complete remission (CR). The interval between BMT and relapse was less than 9 months in 6 patients (2 ABMT and 4 AuBMT) and more than 9 months in 7 patients. Early relapsed patients showed no response to treatment and died at a median of 5.5 months (range 1-13) after relapse. Late relapse after BMT was characterized by a high percentage of response (5 CR and 1 PR), particularly after intensive chemotherapy and by a longer survival (median 14 months; range 2-36). Chemotherapy after transplantation should be carefully evaluated in patients relapsed after BMT in order to select a population that can achieve long term disease free survival.

Adolescent↗
PubMed1994

Characterization of peripheral blood CD34+ progenitor cells mobilized with chemotherapy and granulocyte colony-stimulating factor.

Peripheral blood (PB) mononuclear cells mobilized with chemotherapy and granulocyte colony-stimulating factor (G-CSF) were enriched in CD34+ cells; aliquots were seeded in long-term cultures (LTC) on bone marrow (BM)-derived stromal layers and in liquid cultures containing various growth factors. The final recovery of PB CD34+ cells was similar to normal BM controls, and no difference was found in the expression of CD33 and CD13 antigens; a lower number of CD34+/HLA-DR- cells was found in PB with respect to BM samples (p < 0.001). PB cells sustained hematopoiesis in LTC at least as long as BM cells. At week 3 and 4, PB total mononuclear cell (MC) and CD34(+)-selected cell cultures showed a higher nonadherent cell recovery compared to the respective BM controls (p = 0.05 and p < 0.01). The liquid culture of PB CD34+ cells in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and stem cell factor (SCF) resulted in a marked and long-lasting increase of colony-forming units-granulocyte/macrophage (CFU-GM). Taken together, our data suggest that chemotherapy and G-CSF-primed cells contain a considerable number of both committed and early precursors, accounting for the rapid hematopoietic recovery observed after their reinfusion following myeloablative chemotherapy.

Antigens, CD↗
PubMed1994

[Liposarcoma in the submandibular region. Clinical case].

The authors report a case of liposarcoma in the sub-mandibular region, and they describe the histological species and the way of spreading. They suggest a surgical, non-demolitional therapy, that they carried radical if it is related to a strict follow-up. Anatomical and functional results, after demolishing surgical therapy, are sometimes unacceptable if the real benefits in terms of survival are considered. No supporting therapy has been used because of the presumed insensibility of the neoplasm to the chemo-radiotherapeutic treatments. At 2 years from surgical treatment no local relapses, on distance metastasis have been related.

Aged↗
PubMed1994

Clinical manifestations and management of inherited thrombophilia: retrospective analysis and follow-up after diagnosis of 238 patients with congenital deficiency of antithrombin III, protein C, protein S.

The clinical history of 238 patients with inherited thrombophilia (AT III = 94, PC = 103, PS = 41) was analyzed retrospectively at diagnosis and in the follow-up period after diagnosis. At diagnosis 129 patients (54%) had suffered from thrombosis, with a recurrence rate of 48%. The most frequent onset manifestation was deep vein thrombosis of lower limbs (58%). Thrombotic history started before 40 in 80% of the cases. Forty-nine percent of the venous thromboses were preceded by a triggering event, in most cases pregnancy (17%) and surgery (12%). After diagnosis, follow-up lasted a total of 1,113 pt-years. A policy of short-term prophylaxis during risk situations for all patients and long-term prophylaxis in symptomatic patients failed to prevent venous thrombotic episodes (diagnosed by objective methods) in 4 previously asymptomatic subjects and recurrence in 7 previously symptomatic subjects. After knowledge of the patients' diagnosis the incidence of venous thrombosis/100 pt-years was reduced as compared before diagnosis as total episodes (onset+recurrencies) (1.0 vs 1.9), onset episodes (0.7 vs 1.3) and recurrent episodes (1.3 vs 4.8), even though the differences were not statistically significant. However most of the venous thromboses occurred at a more advanced age (67% after 40 years) and without any apparent cause (83%), at significant variance with the period preceding the diagnosis; in particular the incidence of venous thrombotic onset in patients younger than 40 passed from 1.3/100 pt-years to 0.2/100 pt-years. In 6 recurrences after diagnosis a poor compliance for antithrombotic treatment was recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Esophagocardiomyotomy with Dor gastroplasty in the treatment of esophageal achalasia.

Thirteen patients affected by achalasia of the esophagus, undergoing esophagocardiomyotomy with Dor gastroplasty, are reported. No postoperative deaths or complications occurred. Overall long-term results were satisfactory: excellent or good in 92.3% of cases, fair in 7.7%. Manometry after esophagocardiomyotomy as compared to preoperative assessment showed a decreased resting pressure in the esophageal body, in all patients in whom it was elevated, and the appearance of some peristaltic waves in 23.1% of them (3 patients). As for lower esophageal sphincter, some relaxation after deglutition was observed in one patient. The 24h pH monitoring showed signs of gastroesophageal reflux only in one patient. Based on the obtained results which compare well with those of the literature, the authors be believe that the procedure represents an effective treatment of esophageal achalasia.

Adolescent↗