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Biomedical subjects

G Leone

Publications and source records attributed to G Leone.

At least 271 records · Page 15Linked to original sources
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

Reovirus protein sigma 1: from cell attachment to protein oligomerization and folding mechanisms.

The reovirus cell attachment protein sigma 1 is a lollipop-shaped structure with the fibrous tail anchored to the virion. Since it interacts with the cell receptor, sigma 1 is a major determinant of reovirus infectivity and tissue tropism. Studies on its structure-function relationships have been facilitated by the fact that protein sigma 1 produced in any expression system is capable of binding to cell receptors. The use of site-specific and deletion mutants has led to the identification and characterization of its virion anchorage and receptor binding domains. Studies on the oligomeric status of sigma 1 have revealed that sigma 1 is a homotrimer and that two independent trimerization events at different loci (the N- and C-terminal halves, respectively) of the protein, are involved in its generation. This also accounts for a clearly demonstrable dominant negative effect by a mutant subunit in a wild-type/mutant sigma 1 heterotrimer. Current efforts are focused on the involvement of chaperones in the generation of sigma 1 and on events that take place upon sigma 1 binding to the cell receptor. Protein sigma 1 has therefore become an excellent model system for the study of both virus attachment and protein oligomerization and folding mechanisms.

Animals↗
PubMed1994

Five novel point mutations: two causing haemophilia B and three causing factor X deficiency.

Factors IX and X are plasma glycoproteins important in the middle phase of the coagulation cascade, and a bleeding disorder of variable severity results from abnormalities in the expression of either gene encoding these proteins. Nearly 380 unique molecular mechanisms cause factor IX deficiency, or haemophilia B, but only a limited number of mutations causing congenital factor X deficiency have been characterized to date. In this study enzymatic amplification has been used to examine the molecular basis for factor IX deficiency in two patients and factor X deficiency in two patients. Genomic DNA was isolated from each patient and synthetic oligonucleotide primers were used in the polymerase chain reaction to amplify each exon, splice junction and polyadenylation site. Amplified DNA was then cloned into pUC18 and sequenced. Five novel point mutations were identified, two occurring in the eighth exon of the factor IX gene and three in the eighth exon of the factor X gene. One of the haemophilia B mutations and one of the factor X mutations altered homologous histidine residues near the serine of the catalytic triad.

Base Sequence↗
PubMed1994

Acute parotitis during induction therapy including L-asparaginase in acute lymphoblastic leukemia.

In a patient affected by acute lymphoblastic leukemia (ALL) and subjected to therapy with Erwinia L-asparaginase, acute parotitis was observed. Microbiological studies excluded any infectious etiology. Regression of parotitis was spontaneous. This complication has not been previously reported and could be due to the same mechanism of pancreatic injury. The occurrence of acute parotitis needs to be promptly recognized in order to avoid the continuation of L-asparaginase.

Acute Disease↗
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

Lipids and lipoproteins in acute lymphoblastic leukaemia (ALL).

Current studies suggest a derangement of the cholesterol homeostasis in certain types of leukaemia. The low serum cholesterol levels observed in patients with AML have been related to the tumoral mass and to the disease activity. Only a few studies have taken into consideration a possible change of the serum lipids in ALL. The aim of this study was to evaluate a possible prognostic significance of serum levels of total cholesterol (TC), triglycerides, HDL-C, LDL-C, VLDL-C, apolipoproteins A1 and B and lipoprotein (a), investigated in 10 newly diagnosed ALL patients before and after induction treatment. At diagnosis all these parameters were not significantly different in our patients vs control group except cholesterol and HDL-C levels, which were significantly lower. After the induction treatment, we found a significant increase of HDL-C and Apo A1 values only in those patients that achieved a complete remission. These results support the idea that some serum lipids, such as HDL-C and Apo A1, may have a role as early and reliable markers of the effectiveness of chemotherapy.

Adult↗
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↗
PubMed1994

[Chronobiological standards of 24-hour arterial blood pressure validated by bayesian criteria].

The monodiagnosis of hypertension via ambulatory (A) blood pressure (BP) monitoring (M) is erroneous by definition. Its use has to be substituted by the chronodiagnosis. Because of the lack of an international standardization, the BP chronobiologic reference limits have to be computed on a small sample size. For this compilation, it is, however, unavoidable the recruitment of normotensive subjects using the WHO's fixed limits. These chronobiologic standards are by principle contaminated by false negatives and need a bayesian validation. Such a depuration has been made by reclassifying each subject using the BP time-qualified standards. A secondary sample was constituted on the true normotensive reclassified. This sample provided the a posteriori reference standards for BP. The bayesian chronobiologic reference standards seem to be the limits with which the chronodiagnosis of hypertension can be suitably done via ABPM.

Adult↗
PubMed1994

Microheterogeneity of antithrombin III: effect of single amino acid substitutions and relationship with functional abnormalities.

Microheterogeneity of antithrombin III (AT-III) was investigated by crossed immunoelectrofocusing (CIEF) on eleven molecular variants. A normal pattern was found in five variants while two different abnormal CIEF patterns were found in the other four and two variants, respectively. Point mutations causing a major pI change (exceeding 4.0) of the amino acid substituted lead to alterations in the overall microheterogeneity. The variants thus substituted share a first type of abnormal CIEF pattern with alterations throughout the pH range, regardless of the location of the mutation (reactive site and adjacent regions or heparin binding region). Minor amino acid pI changes in these regions do not alter the AT-III overall microheterogeneity, whatever the resulting functional defect. However, if the mutation is placed in the region around positions 404 or 429, then even minor changes of the amino acid pI seem able to alter the overall charge, leading to a second type of abnormal CIEF pattern with the main alteration at pH 4.8-4.6. Neuraminidase treatment leads to disappearance of microheterogeneity except for the variants with the Arg393 to Cys substitution. Addition of thrombin induces CIEF modifications specifically related to the functional defect. A normal formation of thrombin-antithrombin complexes induces a shift towards the more acid pH range, whereas in the variants substituted at the reactive site the CIEF pattern is substantially unaffected by thrombin; variants substituted at positions 382-384 show a maximal thrombin-induced increase of the isoforms at pI 4.8-4.6. Therefore mutant antithrombins with different functional abnormalities but sharing a common CIEF pattern were well distinguished.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗