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Biomedical subjects

L Ponchio

Publications and source records attributed to L Ponchio.

At least 37 records · Page 2Linked to original sources
PubMed1995

Relationship between transfusion regimen and suppression of erythropoiesis in beta-thalassaemia major.

In the management of beta-thalassaemia major, different transfusion schemes are employed with baseline haemoglobin levels ranging from 8 to over 12 g/dl. We studied the relationship between transfusion regimen and suppression of erythropoiesis in 52 patients with beta-thalassaemia major whose mean pretransfusion haemoglobin levels ranged from 8.6 to 10.9 g/dl. Multiple, regression analysis showed that serum transferrin receptor was the parameter more closely related to mean pretransfusion haemoglobin (r = -0.77, P < 0.001). As measured through serum transferrin receptor, erythroid activity was 1-2 times normal for pretransfusion haemoglobin levels between 10 and 11 g/dl. 1-4 times normal for levels from 9 to 10 g/dl, and 2-6 times normal for levels from 8.6 to 9 g/dl. Mean pretransfusion haemoglobin was also inversely related to serum erythropoietin (r = -0.72, P < 0.001), whereas it showed no or a weak relationship with Hb F, reticulocyte count, or circulating nucleated red cell count. This study suggests that serum transferrin receptor is a reliable indicator of suppression of erythropoiesis in beta-thalassaemia major. On the basis of our findings, pretransfusion haemoglobin values of < or = 9 g/dl should be adopted with caution, because these levels can be associated with an insufficient inhibition of erythroid marrow expansion. However, a transfusion programme, with a baseline haemoglobin of 9-10 g/dl, may provide enough suppression of erythropoiesis and allow a reduction in blood consumption as compared with the classic hyper- or supertransfusion schemes. Since fixed haemoglobin levels may not be the best target for transfusion treatment in all thalassaemic patients, assay of serum transferrin receptor may be helpful for individualizing the transfusion regimens.

Adolescent↗
PubMed1994

Pilot trial of combined administration of erythropoietin and granulocyte colony-stimulating factor to children undergoing allogeneic bone marrow transplantation.

We carried out a pilot study to evaluate the combined use of recombinant human erythropoietin (rhEpo) and granulocyte colony-stimulating factor (G-CSF) for accelerating marrow engraftment in children given allogeneic bone marrow transplantation (BMT). Fifteen consecutive children were enrolled in this study; 13 completed it and were evaluable. Using analysis of variance, laboratory and clinical data referring to these children were compared with those of 15 patients previously treated with rhEpo alone and with those of 16 historical controls. Erythroid repopulation, evaluated sequentially through serum transferrin receptor and reticulocyte count, was similarly accelerated in children receiving rhEpo alone and in those receiving combined treatment. These latter, however, showed a further reduction in the total number of red blood cell units required to reach transfusion independence (1.1 +/- 0.7 in the study population vs 2.7 +/- 1.2 in rhEpo group vs 4.2 +/- 2.3 in historical controls; values are mean +/- 1 SD; p < 0.001). Neutrophil engraftment, i.e. time for neutrophils to reach 0.5 x 10(9)/l, was 11 +/- 3 days in children receiving combined treatment, significantly shorter than that of the control groups (16 +/- 3 and 18 +/- 5, respectively; p < 0.001). Acceleration of neutrophil recovery translated into fewer infections: days of fever were significantly reduced in the study population (4 +/- 2 vs 11 +/- 8 vs 15 +/- 6, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Accelerated erythroid repopulation with no stem-cell competition effect in children treated with recombinant human erythropoietin after allogeneic bone marrow transplantation.

We carried out a pilot study on the use of recombinant human erythropoietin (rHuEPO) to accelerate erythropoietic engraftment in paediatric patients undergoing allogeneic BMT. rHuEPO was administered intravenously at a dose of 75 U/kg per day for 30 d after transplant. Erythroid repopulation, evaluated sequentially through the serum transferrin receptor, was faster in 15 patients receiving rHuEPO than in 16 historical controls (P = 0.0003). This faster erythroid engraftment resulted in a reduction in the total number of red blood cell units required to reach transfusion independence (2.7 +/- 1.2 v 4.2 +/- 2.3, P = 0.027). No significant difference in leucocyte or platelet regeneration was observed. These findings indicate that rHuEPO administration can accelerate erythroid recovery after allogeneic BMT and reduce red cell transfusion requirements with no stem-cell competition effect.

Adolescent↗
PubMed1993

Erythrophagocytosis increases the expression of erythroid potentiating activity mRNA in human monocyte-macrophages.

The aim of the present study was to evaluate whether the erythropoietic response to hemolysis can be mediated by other regulatory peptides in addition to erythropoietin. For this purpose, we have investigated the influence of erythrophagocytosis by human monocytes and macrophages on the mRNA expression of several growth factor genes, including interleukin-3 (IL-3), granulocyte/macrophage colony-stimulating factor (GM-CSF) and erythroid potentiating activity (EPA), which are supposed to influence erythropoiesis. Immunologically mediated erythrophagocytosis increased the expression of EPA mRNA (2 to 3 times). Such increase appeared to be specifically associated with phagocytosis of erythrocytes, since phagocytosis of yeast microorganisms or antibody-coated latex particles had no effect on EPA gene expression. Yeast, however, powerfully stimulated the expression of GM-CSF, granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6) mRNAs which, with the exception of G-CSF, were not influenced by erythrophagocytosis. Erythropoietin and IL-3 mRNAs were never detected in cultured monocytes, either in control or in treated samples. Our findings may suggest that phagocytosis of erythrocytes by monocytes/macrophages increases the expression, and possibly the production, of EPA. This could in turn potentiate the erythropoietic response to extravascular hemolysis by increasing the number of cells responsive to erythropoietin. Thus, EPA might be a mediator of an end-product positive feedback on the rate of red cell production.

Cells, Cultured↗
PubMed1993

Inhibitors of tyrosine phosphorylation induce apoptosis in human leukemic cell lines.

Experimental evidence suggests that hematopoietic growth factors promote cell survival by suppressing apoptosis or programmed cell death. Since interleukin 3 (IL-3) and granulocyte-macrophage colony stimulating factor (GM-CSF) induce tyrosine phosphorylation of a common set of proteins in the factor-dependent cell line M07e, we have investigated whether growth-factor-induced tyrosine phosphorylation is involved in the promotion of cell survival and suppression of apoptosis. Experiments were carried out with the leukemic cell lines HL-60 and M07e and the tyrosine kinase inhibitors genistein and tyrphostin AG82. Both the tyrosine kinase inhibitors induced apoptosis of HL-60 and M07e cells. This was indicated by the appearance of DNA degradation and morphologic evidence of nuclear condensation and fragmentation. It was also confirmed by flow cytometry of DNA, which showed apoptotic cells as a fraction of cells characterized by a diminished DNA stainability, represented on the DNA frequency histograms as a distinct peak below the G0/G1 population. Kinase inhibitors also reduced the fraction of cells in the S phase of the cell cycle. That tyrphostin specifically inhibited tyrosine kinases was further suggested by the prevention of its effects by the tyrosine phosphatase inhibitor sodium orthovanadate (vanadate), at least during the first 18-24 h of treatment. The incomplete prevention of genistein effects by vanadate suggests that genistein is a less specific inhibitor of tyrosine kinases than tyrphostin, and may also act as an inhibitor of topoisomerase II. Vanadate also prevented apoptosis and reduction of the S phase in M07e cells cultured for 24 h in the absence of growth factors. These results suggest that tyrosine phosphorylation is an essential step in IL-3 and GM-CSF signal transduction. Since in our experimental model the effects of tyrosine kinase inhibition and growth factor deprivation could be reversed by concomitant inhibition of tyrosine phosphatases, it is suggested that a balance between tyrosine kinases and tyrosine phosphatases establishes whether a cell will survive or undergo apoptosis.

Apoptosis↗
PubMed1992

Subcutaneous erythropoietin for treatment of refractory anemia in hematologic disorders. Results of a phase I/II clinical trial.

We have used recombinant human erythropoietin (rHuEPO) in a phase I/II clinical trial to evaluate its ability to reverse refractory anemia in hematologic disorders. rHuEPO was administered subcutaneously 5 days per week at escalating doses (50 to 150 U/kg per day). The aim of treatment was a hemoglobin (Hb) level greater than or equal to 10 g/dL without blood transfusion. Of 25 patients treated, 17 were evaluable, most of them with a regular need for transfusion. Eight of these had lymphoproliferative disorders (three cases of malignant lymphoma and five of monoclonal gammopathy) and were exposed to cytotoxic therapy. The other nine patients had hematopoietic stem cell disorders (four cases of myelodysplastic syndrome, three of idiopathic myelofibrosis, and two of chronic myelogenous leukemia). All patients with lymphoproliferative disorder had serum EPO levels inappropriately low for the degree of anemia, while patients with stem cell disorder showed variable values. Erythroid marrow activity was inadequate in all cases. Seven of eight patients with lymphoproliferative disorder responded to treatment maintaining Hb above 10 g/dL without transfusion. The median dose of rHuEPO required for correction of anemia was 75 U/kg. In four cases response was maintained with 50 U/kg, three times per week. There was no complete response among patients with hematopoietic stem cell disorder, although transfusion requirement was eliminated or reduced in four cases. Four patients developed functional iron deficiency during rHuEPO treatment and required iron supplementation to obtain response. Aggravation of splenomegaly was observed in two cases of myeloproliferative disorder. We conclude that: (1) subcutaneous administration of rHuEPO can be effective and safe in patients with lymphoproliferative disorder exposed to chemotherapy and showing inappropriate EPO response to anemia; (2) this is less likely in hematopoietic stem cell disorders, although favorable responses may be observed in occasional patients; and (3) functional iron deficiency as a cause of nonresponse to rHuEPO is frequent also in nonrenal anemia.

Adult↗
PubMed1992

c-abl function in normal and chronic myelogenous leukemia hematopoiesis: in vitro studies with antisense oligomers.

By using antisense oligomers the functional role of the c-abl proto-oncogene in the in vitro growth of bone marrow hematopoietic progenitors from normal subjects and patients with chronic myelogenous leukemia (CML) has been evaluated. Light density bone marrow cells (LDBMs) were depleted of adherent cells, pre-incubated for 15 h with the appropriate oligomer at a concentration of 14 microns, and then plated in methylcellulose for the evaluation of colony formation. Both anti-exon Ia and anti-exon Ib antisense oligomers produced a significant inhibition of normal day 14 CFU-GM growth in vitro (n = 5, 41 +/- 11%, and 36 +/- 7%, respectively; p less than 0.01). In contrast, normal BFU-E growth was not significantly influenced by antisense oligomers (n = 5, 14 +/- 21% and 7 +/- 19%, respectively; p less than 0.05). These findings were confirmed by plating CD34 positive progenitors. When interleukin 3 (IL-3) (100 ng/ml) was added to the culture medium during the preincubation of LDBMCs, the inhibitory effects of antisense oligomers on normal CFU-GM growth were abolished. Seven patients with CML were also studied, all of whom had cytogenetic evidence of 100% clonal hematopoiesis. In five patients in the chronic phase, antisense oligomers were inhibitory on in vitro growth of both day 14 CFU-GM (37 +/- 20% and 37 +/- 15%, p less than 0.05) and BFU-E (45 +/- 15% and 41 +/- 11%, p less than 0.05), and this inhibition was not removed by pre-incubation with IL-3. No significant effect was observed on cluster or colony formation in two patients with CML in accelerated or blastic phase, and on in vitro growth of clonogenic cells from the Ph1-positive K-562 cell line. These findings (i) confirm previous observations showing a lineage specific requirement of c-abl function in normal hematopoiesis, and (ii) suggest that the residual c-abl expression has a role in chronic phase CML hematopoiesis, as its inhibition impairs both myeloid and erythroid colony formation in vitro.

Base Sequence↗
PubMed1991

Cytotoxic activity of an anti-transferrin receptor immunotoxin on normal and leukemic human hematopoietic progenitors.

The process of cellular iron uptake involves a specific receptor for the plasma carrier transferrin and a pathway of receptor-mediated endocytosis. Transferrin receptor expression is closely related to the rate of cell proliferation, and conjugates between anti-transferrin receptor monoclonal antibodies and toxins have been shown to have potent cytotoxic activity. We have constructed an anti-transferrin receptor immunotoxin by conjugating the anti-transferrin receptor monoclonal antibody B3/25 to a ribosome-inactivating protein, the saporin-6 (SO6), which is derived from the seeds of the plant Saponaria officinalis. The immunotoxin B3/25-SO6 was tested for in vitro cytotoxic activity against the human cell lines K-562 and HL-60 and against normal human bone marrow hematopoietic progenitors and acute myeloid leukemia clonogenic cells. The immunotoxin proved to be an effective inhibitor of K-562 and HL-60 clonogenic cell growth, in vitro colony formation being completely inhibited at immunotoxin concentrations ranging from 10(-7) to 10(-10) M. B3/25-SO6 markedly reduced the recloning efficiency of HL-60 clonogenic cells at 10(-12) M. Exposure of HL-60 cells in suspension culture to 10(-9) M B3/25-SO6 for 48-72 h completely abolished their clonogenic potential. The immunotoxin was also found to be cytotoxic against normal human bone marrow progenitor cells (burst-forming unit-erythroid and colony-forming unit-granulocyte, macrophage) in a dose-dependent manner. However, exposure of normal colony-forming unit-granulocyte, macrophage in suspension culture to 10(-9) M B3/25-SO6 for 72 h resulted in only 50% suppression of their clonogenic potential. Finally, B3/25-SO6 was found to be a potent inhibitor of in vitro growth of acute myeloid leukemia clonogenic cells. The cytotoxic effects of B3/25-SO6 were shown to be specific, since both saporin alone and irrelevant immunotoxins did not have any effect in the cellular systems examined. We conclude that the immunotoxin B3/25-SO6 has dose-related cytotoxic effects on both normal and leukemic human hematopoietic progenitors. Since there are substantial differences between normal and leukemic progenitors with respect to the proportion of cycling cells and the expression of transferrin receptors, B3/25-SO6 or similar immunotoxins may have clinical application in bone marrow-purging procedures.

Antibodies, Monoclonal↗
PubMed1991

Tumor necrosis factor alpha modulates the messenger RNA expression of hematopoietic growth factor genes in fresh blast cells from patients with acute myeloblastic leukemia.

Tumor necrosis factor alpha (TNF-alpha) has been previously shown to modulate the expression of hematopoietic growth factor genes in monocytes and other mesenchymal cells. As acute myeloblastic leukemia (AML) blasts can express and produce hematopoietic growth factors, the influence of TNF-alpha on the accumulation of mRNAs for c-myc, interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, IL-6 and IL-1 beta was evaluated in fresh blasts from 13 patients with AML. Total cellular RNA was extracted from blast cells cultured for 24 hours with or without TNF-alpha (500 U/ml). The c-myc transcript level was decreased by TNF-alpha treatment in 9/13 cases, and increased in only one case. Among the growth factor genes, the GM-CSF gene was more often and consistently influenced by TNF-alpha, increased levels of its transcript being observed in 6/13 cases following treatment with the cytokine; in no case was there a reduction of GM-CSF mRNA. G-CSF and IL-6 transcripts were more heterogeneously influenced, whereas the IL-3 transcript was never detected in our AML samples. The IL-1 beta message was present in 8/13 untreated and in 13/13 TNF-alpha treated samples. Moreover, in untreated cells, GM-CSF, G-CSF and IL-6 expression was always associated with IL-beta expression. These findings indicate that TNF-alpha can modulate the levels of growth factor transcripts in AML blasts, and raise questions about the effects of TNF-alpha on leukemic hematopoiesis, considering that TNF-alpha, IL-1 and GM-CSF can synergistically stimulate the growth of AML clonogenic cells.

Gene Expression Regulation, Leukemic↗
PubMedDate not supplied

Poor outcome of patients with resectable breast cancer receiving adjuvant high-dose sequential chemotherapy following preoperative treatment.

BACKGROUND/OBJECTIVES: The prognosis of resectable high risk breast cancer (BC) patients (N+ > 10) is poor with a five-year disease-free survival (DFS) after standard adjuvant ADM/CMF chemotherapy (CT) of about 40%. An improvement in survival has been reported when high-dose chemotherapy with autologous stem cell support is given. It has been recently suggested that nodal status and the degree of pathological remission following preoperative CT administered in patients harbouring tumors larger than 3 cm represent the most important prognostic factors for DFS. Since no data are available regarding the impact of primary CT in the high dose CT adjuvant setting, we retrospectively evaluated the efficacy of administering megadoses of cytotoxic drugs with stem cell support in the subgroup of patients showing poor response to preoperative CT., PATIENTS AND METHODS: Fourteen women with high risk BC, N+ > 10 and tumor size > 3 cm following antracyclin-based primary CT, received high dose sequential chemotherapy (HDS). The median number of positive axillary nodes at surgery was 18 and tumor size was greater than 5 cm in 6 patients. HDS chemotherapy consisted of cyclophosphamide (7 gr/m2), methotrexate (8 gr/m2) plus vincristin (2 mg), 2 courses of carboplatin (360 mg/m2), and Thiotepa (600 mg/m2) plus L-PAM (160 mg/m2) as final myeloablative regimen requiring stem cell support. RESULTS: At a minimum follow up of 12 months (median 18 months, range 12-40) 5 patients remained disease free (36%) and 9 (64%) have relapsed (7 within the first 10 months). CONCLUSION: Our retrospective analysis suggests that BC patients showing poor response to primary CT might fail to achieve the benefits expected from high dose intensification.

Adult↗
PubMedDate not supplied

Evaluation of erythroid marrow response to recombinant human erythropoietin in patients with cancer anaemia.

BACKGROUND: Anaemia is a frequent finding in patients with cancer and may be due to different causes, including blunted erythropoietin production. MATERIALS AND METHODS: In a pilot study, we administered recombinant human erythropoietin (rHuEPO) to twelve patients with solid tumours and secondary anaemia. rHuEPO was given subcutaneously 5 d per week at escalating doses (75 to 150 U/kg per day): the aim of treatment was a Hb level > or = 10 g/dl without blood transfusion. We evaluated endogenous EPO production through serum EPO levels and erythroid marrow activity by means of serum transferrin receptor (TfR). RESULTS: Six out of 12 subjects had defective endogenous EPO production. All patients but two responded to treatment with steady increases in Hb levels above 10 g/dl, and the median dose of rHuEPO required for correction of anaemia was 75 U/kg. Response was associated with an early increase in serum TfR. Six patients developed functional iron deficiency and required iron supplementation to obtain response. Treatment improved functional ability in 4/10 responders. CONCLUSIONS: Subcutaneous rHuEPO can stimulate erythroid marrow activity in cancer anaemia, even in patients with advanced disease, and marrow response can be adequately monitored by serum TfR. Functional iron deficiency as a cause of nonresponse to rHuEPO is frequent in these patients and may require parenteral iron administration. Although erythropoietin can improve the anaemia of cancer, the decision to treat should be individualised for each patient, looking more at the quality of life and cost-effectiveness than at cosmetic increases in the haemoglobin level.

Aged↗
PubMedDate not supplied

Pure red cell aplasia following peripheral stem cell transplantation: complete response to a short course of high-dose recombinant human erythropoietin.

We studied a patient who developed pure red cell aplasia (PRCA) following peripheral stem cell transplantation for non-Hodgkin lymphoma. Serum erythropoietin was appropriate for the degree of anemia. Corticosteroid treatment was ineffective. Four months after transplantation rHuEpo was administered subcutaneously at a dose of 150 U/Kg per day, five days a week for 8 weeks. Treatment induced an erythropoietic response and corrected anemia. Response was maintained following discontinuation of rHuEpo. This study and previous reports indicate that high doses of rHuEpo given over a short time can resolve PRCA following autologous or allogeneic stem cell transplantation.

Dose-Response Relationship, Drug↗
PubMedDate not supplied

Effect of recombinant human erythropoietin on hematopoietic and non-hematopoietic malignant cell growth in vitro.

BACKGROUND: Several clinical studies have shown that recombinant human erythropoietin (rHuEpo) can ameliorate the anemia associated with hematologic malignancies and solid tumors. On the other hand, only a few studies have been performed to investigate whether rHuEpo can affect or modulate the growth of malignant cells. MATERIALS AND METHODS: We studied the effects of rHuEpo (0.5 to 10 IU/mL) on clonogenic growth and cell kinetics in ten cell lines derived from both hematologic malignancies and solid tumors. Clonogenic assays were performed by plating 5 x 10(3) cells in agar, while the percentage of cells in S phase was assessed by DNA flow cytometry. RESULTS: rHuEpo did not affect either in vitro colony formation or S phase percentage in the human erythroid cell lines K-562 and HEL expressing erythropoietin receptors (< 40 receptors per cell). No effect of rHuEpo was observed in the remaining hematopoietic cell lines or in five solid tumor cell lines. CONCLUSIONS: These findings indicate that rHuEpo, even at very high concentrations, does not affect either clonogenic growth or DNA synthesis in the cell lines tested. Available evidence suggests that rHuEpo can be safely employed in all malignancies except acute myeloid leukemia.

Cell Division↗