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P Strippoli

Publications and source records attributed to P Strippoli.

At least 19 recordsLinked to original sources
PubMed1999

Long-term bone marrow cultures in Diamond-Blackfan anemia reveal a defect of both granulomacrophage and erythroid progenitors.

The hematopoietic defect of Diamond-Blackfan anemia (DBA) results in selective failure of erythropoiesis. Thus far, it is not known whether this defect originates from an intrinsic impediment of hematopoietic progenitors to move forward along the erythroid pathway or to the impaired capacity of the bone marrow (BM) microenvironment to support proliferation and differentiation of hematopoietic cells. Reduced longevity of long-term bone marrow cultures, the most physiologic in vitro system to study the interactions of hematopoietic progenitors and hematopoietic microenvironment, is consistent with a defect of an early hematopoietic progenitor in DBA. However, stromal adherent layers from DBA patients generated in a long-term culture system, the in vitro counterpart of BM microenvironment, did not show evidence of any morphologic, phenotypic, or functional abnormality. Our major finding was an impaired capacity of enriched CD34+ BM cell fraction from DBA patients, cultured in the presence of normal BM stromal cells, to proliferate and differentiate along the erythroid pathway. A similar impairment was observed in some DBA patients along the granulomacrophage pathway. Our result points to an intrinsic defect of a hematopoietic progenitor with bilineage potential that is earlier than previously suspected as a relevant pathogenetic mechanism of the disease. The finding of impaired granulopoiesis in some DBA patients underlines the heterogeneity of this rare disorder.

Adolescent↗
PubMed1999

Thrombopoietin and interleukin 11 have different modulatory effects on cell cycle and programmed cell death in primary acute myeloid leukemia cells.

The c-mpl ligand, thrombopoietin (TPO), is a physiologic regulator of platelet and megakaryocytic production, acting synergistically on thrombopoiesis with the growth factors interleukin 11 (IL-11), stem cell factor, interleukin 3 (IL-3), interleukin 6 (IL-6), and granulocyte-macrophage colony-stimulating factor. Because some of these growth factors, especially TPO and IL-11, are now being evaluated clinically to reduce chemotherapy-associated thrombocytopenia in cancer patients, we evaluated 25 acute myeloid leukemia (AML) samples to test whether TPO, IL-11, and other early-acting megakaryocyte growth factors can affect leukemic cell proliferation, cell cycle activation, and programmed cell death (PCD) protection. TPO induced proliferation in the majority of AML samples from an overall mean proportion of S-phase cells of 7.8% +/-1.5% to 14.5% +/- 2.1% (p = 0.0006). Concurrent G0 cell depletion was found in 47.3% of AML samples. TPO-supported leukemic cell precursor (CFU-L) proliferation was reported in 5 of 17 (29.4%) of the samples with a mean colony number of 21.4 +/- 9.6 x 10(5) cells plated. In 13 of 19 samples, a significant protection from PCD (from an overall mean value of 13% +/-0.7% to 8.8% +/- 1.8%;p = 0.05) was detected after TPO exposure. Conversely, IL-11-induced cell cycle changes (recruitment from G0 to S phase) were detected in only 2 of 14 samples (14.2%). In addition, IL-11 showed little, if any, effect on CFU-L growth (mean colony number = 17.5 9.5) or apoptosis. Combination of TPO with IL-11 resulted in only a slight increase in the number of CFU-L, whereas IL-3 and stem cell factor significantly raised the mean colony numbers up to 119.2 +/- 68.3 and 52.9 +/- 22.1 x 10(5) cells plated, respectively. We conclude that TPO induces cell cycle activation in a significant proportion of cases and generally protects the majority of AML blast cells from PCD. On the other hand, IL-11 has little effect on the cell cycle or PCD. Combination of both TPO and IL-11 is rarely synergistic in stimulating AML clonogenic growth. These findings may be useful for designing clinical studies aimed at reducing chemotherapy-associated thrombocytopenia in AML patients.

Acute Disease↗
PubMed1999

Regioselective synthesis and biological profiling of butyric and phenylalkylcarboxylic esters derivated from D-mannose and xylitol: influence of alkyl chain length on acute toxicity.

Regiospecific synthesis of 12 novel n-butyric and phenylalkylcarboxylic monoesters of mannose and xylitol was achieved. The strategy adopted, avoided a tedious intramolecular transesterification step, previously described for the synthesis of analogous compounds and permitted the facile synthesis of a new generation of stable derivatives. The general tolerance of the drugs has been assayed after intravenous administration of a bolus dose into mice. Monobutyric esters showed a low toxicity commensurate with the requirements for future development. A relationship was observed between chain length and toxicity. In contrast, phenylacetic, 3-phenylpropionic and 4-phenylbutyric esters were found to be toxic. Phenylbutyric esters induced marked and specific neuromuscular damage. Preliminary biological investigations of the new series of monobutyric esters showed them to retain the benificial biological properties of butyric acid whilst remaining relatively non toxic. They induced an inhibition of in vitro proliferation of 10 human cases of de novo acute myeloid leukemia (AML) primary cultures and AML established cell lines. AML blasts growth appeared to be blocked and cell differentiation was established. Transcription and expression of maturation markers and finally apoptosis were observed. Moreover, human gamma-chain hemoglobin (HbF) synthesis in erythroleukemia cells was stimulated by monobutyric esters. Mannose and xylitol butyric derivatives would appear to have exciting potential in treatment of beta-Hemoglobinopathies, sickle cell anemia and cancer.

Animals↗
PubMed1998

Production of stem cell factor and expression of c-kit in human rhabdomyosarcoma cells: lack of autocrine growth modulation.

Human rhabdomyosarcoma cells produce autocrine and paracrine growth factors that can sustain their growth and malignancy. Here we report constitutive production of stem cell factor (SCF) by 5 of 5 human rhabdomyosarcoma cell lines both of alveolar and embryonal histotype. SCF production, ranging from 30 to 162 pg/ml, was independent from the degree of myogenic differentiation and was not modulated by exogenous addition of retinoic acid (RA) or tumor necrosis factor-alpha (TNF-alpha). Four of 5 rhabdomyosarcoma cell lines expressed the mRNA for SCF receptor c-kit, while the 5th cell line became weakly positive for c-kit mRNA only after stimulation with retinoic acid. On the cell surface, c-kit protein was detectable at very low levels in only 1 of 5 rhabdomyosarcoma cell lines and was not up-regulated by RA or TNF-alpha. Addition of anti-c-kit and anti-SCF blocking antibodies, or of exogenous SCF did not alter the in vitro growth ability of rhabdomyosarcoma cells. In conclusion, our data show that rhabdomyosarcoma cells produce consistent amounts of SCF but did not demonstrate autocrine growth modulation. SCF secretion may thus have a paracrine, rather than an autocrine activity in this tumor.

Autocrine Communication↗
PubMed1998

Mutational screening of thrombopoietin receptor gene (c-mpl) in patients with congenital thrombocytopenia and absent radii (TAR).

Thrombocytopenia with absent radii (TAR) is a rare autosomal recessive disease characterized by hypomegakaryocytic thrombocytopenia and bilateral radial aplasia. We performed mutational screening of coding and promoter regions of the c-mpl gene, encoding thrombopoietin (TPO) receptor, by sequence analysis in four unrelated patients affected by TAR syndrome. Our results indicate that c-mpl gene mutations are not a common cause of thrombocytopenia in TAR syndrome.

Adolescent↗
PubMed1997

Regulation of polymorphonuclear cell activation by thrombopoietin.

Thrombopoietin (TPO) regulates early and late stages of platelet formation as well as platelet activation. TPO exerts its effects by binding to the receptor, encoded by the protooncogene c-mpl, that is expressed in a large number of cells of hematopoietic origin. In this study, we evaluated the expression of c-Mpl and the effects of TPO on human polymorphonuclear cells (PMN). We demonstrate that PMN express the TPO receptor c-Mpl and that TPO induces STAT1 tyrosine phosphorylation and the formation of a serum inducible element complex containing STAT1. The analysis of biological effects of TPO on PMN demonstrated that TPO, at concentrations of 1-10 ng/ml, primes the response of PMN to n-formyl-met-leu-phe (FMLP) by inducing an early oxidative burst. TPO-induced priming on FMLP-stimulated PMN was also detected on the tyrosine phosphorylation of a protein with a molecular mass of approximately 28 kD. Moreover, we demonstrated that TPO by itself was able to stimulate, at doses ranging from 0.05 to 10 ng/ml, early release and delayed synthesis of interleukin 8 (IL-8). Thus, our data indicate that, in addition to sustaining megakaryocytopoiesis, TPO may have an important role in regulating PMN activation.

Animals↗
PubMed1997

An erythroid and megakaryocytic common precursor cell line (B1647) expressing both c-mpl and erythropoietin receptor (Epo-R) proliferates and modifies globin chain synthesis in response to megakaryocyte growth and development factor (MGDF) but not to erythropoietin (Epo).

A human megakaryocyte cell line (B1647) has been established from bone marrow cells obtained from a patient with acute myelogenous leukaemia (FAB M2). The cells were CD34-, CD33+, HLA-DR+, CD38+, and expressed the immunophenotypic markers of the megakaryocyte lineage (CD41 and von Willebrand factor). Moreover the cells expressed the c-mpl (thrombopoietin receptor) mRNA and protein. On the other hand, the B1647 cells also possessed erythroid lineage characteristics: the vast majority of cells were glycophorin positive, and about 10% of unstimulated cells stained with an anti-globin gamma chain MoAb. In addition, S1 protection analysis demonstrated expression of beta-globin mRNA, and Epo receptor (Epo-R) protein was detected by cytofluorimetric assay. Several growth factors, when tested alone or in combination, failed to influence the B1647 cell growth. A significant increase of cell proliferation was observed only after the addition, in serum-free culture, of recombinant human megakaryocyte growth development factor (MGDF), a recombinant c-mpl ligand encompassing the receptor-binding domain and identical to thrombopoietin (TPO), at concentrations ranging from 0.01 to 1 ng/ml. Interestingly, MGDF failed to induce megakaryocytic differentiation of the B1647 cells, but significantly increased the synthesis of the globin gamma-chain. B1647 cells could be a useful model for studying the biological effect of TPO on common megakaryocyte and erythroid progenitors.

Cell Division↗
PubMed1997

Mutations of the Fanconi anemia group A gene (FAA) in Italian patients.

Fanconi anemia (FA) is an autosomal recessive disease characterized by progressive pancytopenia, congenital malformations, and predisposition to acute myeloid leukemia. At least five complementation groups (FA-A-FA-E) have been identified. The relative prevalence of FA-A has been estimated at an average of approximately 65% but may widely vary according to ethnic background. In Italy, 11 of 12 patients analyzed by cell-fusion studies were assigned to group FA-A, suggesting an unusually high relative prevalence of this FA subtype in patients of Italian ancestry. We have screened the 43 exons of the FAA gene and their flanking intronic sequences in 38 Italian FA patients, using RNA-SSCP. Ten different mutations were detected: three nonsense and one missense substitutions, four putative splice mutations, an insertion, and a duplication. Most of the mutations are expected to cause a premature termination of the FAA protein at various sites throughout the molecule. Four protein variants were also found, three of which were polymorphisms. The missense mutation D1359Y, not found in chromosomes from healthy unrelated individuals, was responsible for a local alteration of hydrophobicity in the FAA protein, and it was likely to be pathogenic. Thus, the mutations so far encountered in the FAA gene are essentially all different. Since screening based on the analysis of single exons by genomic DNA amplification apparently detects only a minority of the mutations, methods designed to detect alterations in the genomic structure of the gene or in the FAA polypeptide may be helpful in the identification of FAA mutations.

Cell Cycle Proteins↗
PubMed1997

Stem cell factor suppresses apoptosis in neuroblastoma cell lines.

Stem cell factor (SCF) is a glycoprotein growth factor produced by marrow stromal cells that acts after binding to its specific surface receptor, which is the protein encoded by the protooncogene c-kit. SCF synergizes with specific lineage factors in promoting the proliferation of primitive hematopoietic progenitors, and has been administered to expand the pool of these progenitors in cancer patients treated with high-dose chemotherapy. SCF and its c-kit receptor are expressed by some tumor cells, including myeloid leukemia, breast carcinoma, small cell lung carcinoma, melanoma, gynecological tumors, and testicular germ cell tumors. Previous studies of SCF in neuroblastoma have produced conflicting conclusions. To explore the role of SCF in neuroblastoma, we studied five neuroblastoma lines (IMR-5, SK-N-SH, SK-N-BE, AF8, and SJ-N-KP) and the neuroepithelioma line CHP-100. All lines expressed mRNA for c-kit and c-kit protein at low intensity as measured by flow cytometry, and secreted SCF in medium culture as shown by ELISA. Exogenous SCF did not modify 3H thymidine uptake in the neuroblastoma and neuroepithelioma cell lines. After 6 days' culture in the presence of anti-c-kit, the number of viable neuroblastoma cells was significantly lower than the control, and terminal deoxynucleotidyl transferase assay showed a substantial increase of apoptotic cells: The percentage of positive cells was 1-3% in the control lines, whereas in the presence of anti c-kit it varied from 29% of SK-N-BE to 92% of CHP-100. After 9 days' culture in the presence of anti-c-kit, no viable cells were detectable. These data indicate that SCF is produced by some neuroblastoma cell lines via an autocrine loop to protect them from apoptosis.

Antibodies, Monoclonal↗
PubMed1995

Cross-sectional comparison of malnutrition in continuous ambulatory peritoneal dialysis and hemodialysis patients.

Although malnutrition is not uncommon in continuous ambulatory peritoneal dialysis (CAPD) and maintenance hemodialysis (MHD) patients, there has never been a large-scale comparison study of nutritional status with these two dialysis modalities. We therefore assessed protein-calorie nutrition in 224 CAPD patients and 263 MHD patients who were treated in eight centers in Italy. The CAPD patients were slightly older than the MHD patients (60.2 +/- 14.2 years v 56.3 +/- 15.1 years; P < 0.01), had undergone dialysis for less time (2.32 +/- 2.10 years v 3.66 +/- 2.66 years; P < 0.0001), and had higher residual renal function (1.83 +/- 2.29 mL/min v 0.27 +/- 0.91 mL/min; P < 0.0001). Protein nitrogen appearance was 60.5 +/- 16.6 g/d and 61.9 +/- 16.5 g/d in the CAPD and MHD patients, respectively. In CAPD versus MHD patients, serum total protein and albumin tended to be lower; serum transferrin and midarm muscle circumference were similar; and relative body weight, skinfold thickness, and estimated percent body fat tended to be greater. These greater values in CAPD patients were particularly evident in those who were 65 years of age or older. Serum glucose, total cholesterol, and triglycerides also were greater in CAPD patients. The subjective global nutritional assessment indicated a significantly greater proportion of malnourished CAPD patients than MHD patients (42.3% v 30.8%). The greater prevalence of malnutrition in CAPD patients diminished with age. Maintenance hemodialysis patients older than 76 years were more likely to be malnourished than CAPD patients. In patients less than 65 years of age, protein-calorie malnutrition was more likely to be present in CAPD patients than in MHD patients.

Adult↗
PubMed1995

Nutritional status in the elderly patient with uraemia.

An increasing number of elderly patients with uraemia are treated by dialysis therapy. Virtually every published study on nutritional status of patients undergoing maintenance haemodialysis treatment or continuous ambulatory peritoneal dialysis (CAPD) has indicated that a substantial proportion of patients undergoing regular dialysis treatment have protein calorie malnutrition. Problems of undernutrition increase significantly with age; a combination of socioeconomic, psychological, and biochemical problems interfering with acquiring and assimilating a balanced diet are responsible for nutritional deficiencies in older people. We assessed the prevalence of protein calorie malnutrition in 183 regular dialysis patients aged 65 years or older treated with haemodialysis or CAPD. This group of patients was compared to two other groups aged 18-40 years (62 patients) and 41-64 years (239 patients). Presence of malnutrition was assessed by selected serum chemistries, anthropometry and Subjective Global Nutritional Assessment. Adequacy of dialysis, protein nitrogen appearance, as an index of protein intake, and residual renal function were measured. The results indicate that protein calorie malnutrition occurs commonly in regular dialysis patients, with a higher prevalence of malnutrition in the elderly; 51% of patients of the elderly group were classified as malnourished, and no difference was found with the two dialytic modalities.

Adolescent↗
PubMed1995

Epithelial cells are the major source of biologically active granulocyte macrophage colony-stimulating factor in human endometrium.

Granulocyte macrophage colony-stimulating factor (GM-CSF) has emerged as an important growth factor for trophoblast and other placental cells, leading to improved placental functioning and fetal survival. Recent observations have indicated that GM-CSF is synthesized by epithelial cells in the murine pregnant and non-pregnant uterus. In this study, the production of GM-CSF by cells derived from human endometrium is assessed using a sensitive bioassay and specific neutralization of the cytokine bioactivity with a monoclonal antibody to GM-CSF. Originally, GM-CSF was assayed in the culture supernatants of explant cultures of human endometria. Concentrations of GM-CSF up to 4440 pg/ml were detected. Subsequently, enriched epithelial cell cultures were prepared from glands isolated from human endometrium. The purity of epithelial cultures was demonstrated by the expression of cytokeratin, a weak immunoreactivity for vimentin and a lack of immunoreactivity for leukocyte common antigen, CD68, a macrophage-specific protein and endothelial marker (factor VIII-related antigens). Detected concentrations of GM-CSF were as high as 18,800 pg/ml. Furthermore, pure epithelial cells of a neoplastic endometrial cell line ECC1 secreted GM-CSF, confirming the ability of endometrial epithelial cells to secrete this cytokine. The immunostaining of dated endometria from proliferative and secretory phases showed primarily that epithelial cells, and to a lesser extent stromal cells, exhibited immunoreactivity for GM-CSF. A Western blot analysis, performed to validate the immunohistochemical data, confirmed the presence of an immunoreactive gene product for GM-CSF in human endometrium throughout the menstrual cycle. These findings indicate that human endometrium synthesizes GM-CSF and that epithelial cells are a major contributor to its production.

Adult↗
PubMed1995

Cytofluorimetric and functional analysis of c-kit receptor in acute leukemia.

The SR-1 monoclonal antibody (MoAb) recognizes an epitope of the c-kit receptor (KR), present on normal hemopoietic CD34+ stem cells as well as on blasts from patients with acute leukemia. Cytometric analysis by indirect immunofluorescence with the SR-1 MoAb was performed in 98 patients with acute myeloblastic leukemia (AML) and in 37 patients with acute lymphoblastic leukemia (ALL) in order to detect the presence of the KR and to examine its prognostic significance. Sixty-nine of 98 (70%) AML patients were SR-1 positive independently of the FAB subtype, although a higher incidence of SR-1 positive cases was observed in M4 and M5 AML and in those cases that also coexpressed lymphoid antigens. Fourteen AML samples were studied by Northern blot analysis and the KR mRNA was detected in the majority of SR-1 positive cases and also in 2 of 3 SR-1 negative samples. Furthermore, "in vitro" cultures from 15 cases showed that recombinant human Stem cell factor (rhSCF) induced an increased proliferative activity in most tested cases (11/15); this was further enhanced when rhSCF was combined with rhIL-3 + rhGM-CSF (p = 0.007) and with the GM-CSF/IL-3 fusion protein PIXY321 (p = 0.003). Thirty-seven ALL cases were also studied and all but one were SR-1 negative. Interestingly, the only SR-1 positive case also coexpressed myeloid antigens and showed an "in vitro" response when stimulated with rhSCF. Finally, the complete remission (CR) rate, survival and event-free survival were evaluated in 75 AML patients who received standard and identical chemotherapy; unlike previous studies which utilized a different anti-KR MoAb (YB5.B8) and which showed a poor prognosis for KR positive patients, we were unable to document any significant difference in CR rate, survival and event-free survival.

Adolescent↗
PubMed1993

Clinical implications of the heterogeneity of hematopoietic progenitors elicited in peripheral blood by anticancer therapy with cyclophosphamide and cytokine(s).

Clinical investigators have found that the hematopoietic system irreversibly damaged by cancer therapy with myeloablative high doses of chemoradiotherapy can be reconstituted by transplantation of autologous hematopoietic progenitors retrieved from peripheral blood. In comparison with patients transplanted with bone marrow, those who receive peripheral blood progenitors undergo shorter periods of neutropenia and thrombocytopenia, require less platelet and erythrocyte transfusions and, most importantly, experience overall reduced treatment-related morbidity. In this article, we speculate that an explantation for this clinical achievement may be that committed hematopoietic progenitors as well as ancestral uncommitted pluripotent stem cells are retrieved from circulation and transplanted after myeloablative cancer therapy. As indicated by studies in rodents, transplantation of hematopoietic progenitors is followed by two phases of engraftment associated with progenitors at different stages of maturation. An initial phase corresponding to early hematopoietic recovery is produced by committed progenitors, and a second sustained engraftment phase is produced by the pluripotent stem cell. Should this multiphase engraftment model be true of humans also, the exceptionally prompt and sustained blood cell count recovery achieved by transplanting blood progenitor cells may reflect transplantation of heterogeneous progenitors such as committed progenitors and pluripotent stem cells producing an early engraftment phase and then sustained hematopoiesis, respectively.

Antineoplastic Agents↗
PubMed1993

M-07e cell bioassay detects stromal cell production of granulocyte-macrophage colony stimulating factor and stem cell factor in normal and in Diamond-Blackfan anemia bone marrow.

Ten healthy donors and four patients with Diamond-Blackfan anemia (DBA) have been investigated for granulocyte-macrophage colony stimulating factor (GM-CSF) and stem cell factor (SCF) production by bone marrow-enriched fibroblasts (BMEF) in a highly sensitive biological assay on growth factor-dependent M-07e cells. M-07e cells detected active soluble kit-ligand from normal bone marrow fibroblasts as well as from DBA BMEF which produce constitutively significant amounts of SCF. Interleukin 1 beta (IL-1 beta) induced a significant increase of soluble SCF from both normal and DBA BMEF. GM-CSF was undetectable in unstimulated cultures, while its production by bone marrow microenvironmental cells was documented for both normal and DBA patients after IL-1 beta stimulation in vitro.

Adult↗
PubMed1993

Production of interleukin 6, leukemia inhibitory factor and granulocyte-macrophage colony stimulating factor by peripheral blood mononuclear cells in Fanconi's anemia.

The aim of this study was to test the in vitro cytokine production by peripheral blood mononuclear cells (PBMCs) in patients with Fanconi's anemia (FA). Phytohemagglutinin (PHA)-stimulated PBMCs from 21 patients with FA were studied for their ability to produce interleukin 6 (IL-6), leukemia inhibitory factor (LIF) and granulocyte-macrophage colony stimulating factor (GM-CSF). Enzymatic immunoassay (EIA) was used for both IL-6 and LIF, while GM-CSF was evaluated in a highly sensitive biological assay provided by GM-CSF-dependent M-07e cells. A significant decrease of IL-6 was detected in 9 out of 11 FA patients compared with five normal donors, while similar amounts of LIF were produced from 21 FA patients and 21 healthy subjects. A drastic increase of active GM-CSF was documented in PHA-stimulated PBMC-conditioned medium in all 18 FA patients tested. Since IL-6 and GM-CSF play an important role in maintaining basal hemopoiesis, our results suggest that an abnormal cytokine network may be involved in the pathogenesis of FA pancytopenia.

Adolescent↗