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Biomedical subjects

C Almici

Publications and source records attributed to C Almici.

At least 37 records · Page 2Linked to original sources
PubMed1994

Autologous transplant for chronic myelogenous leukemia using marrow treated ex vivo with mafosfamide.

Ten adult patients with Ph-positive chronic myelogenous leukemia (CML) received autologous transplantation using marrow treated ex vivo with mafosfamide. At transplant, 7 patients were in chronic phase (5 in first, 2 in second) and 3 in accelerated phase. The median time to achieve 500 x 10(6)/l neutrophils was 32 days (range 17-72 days). A platelet count of 20 x 10(9)/l was achieved at a median of 40 days (range 24-151 days). After transplant, cytogenetic analysis revealed 100% Ph-negative marrow metaphases in 6 of 9 analyzable patients with a median duration of Ph-negative hematopoiesis of 6.5 months. After a median follow-up of 16 months (range 3-31 months), five patients evolved into blast crisis, two died of non-hematological causes, one is Ph-negative in chronic phase at +4 and one is in chronic phase, but Ph-positive, at +22. In conclusion, this pilot study demonstrates that: (1) engraftment can occur from Ph-negative stem cells selected by mafosfamide, (2) mafosfamide purging may induce a transient period of Ph-negative hematopoiesis, and (3) modifications of the purging procedure and post-transplant manipulations of the immune-hematopoietic system are required to prolong cytogenetic remission.

Adult↗
PubMed1993

Effect of recombinant human stem cell factor on mafosfamide-treated bone marrow clonogenic cells.

The availability of early-acting cytokines could allow the establishment of new approaches to chemical marrow purging. It was the aim of the present study to investigate the capability of recombinant human stem cell factor (SCF) in combination with other growth factors to support the in vitro growth of mafosfamide-treated progenitor cells such as mixed colony forming units (CFU-GEMM), erythroid burst forming units (BFU-E) and granulocyte-macrophage CFU (CFU-GM). When marrow cells were incubated (30 min, 37 degrees C) with increasing doses of mafosfamide (30-120 micrograms/ml) a statistically significant (p < or = .05), dose-dependent suppression of colony growth was observed. Addition of SCF (50 ng/ml) to marrow cultures stimulated with the standard mixture of growth factors (interleukin 3 or IL-3, granulocyte-macrophage colony stimulating factor or GM-CSF, and erythropoietin or Epo) significantly increased the mean (+/- SD) concentration of mafosfamide inducing 95% inhibition of CFU-GM (106 +/- 17 versus 130 +/- 29, p < or = .0005), but not granulocyte/erythroid/macrophage/megakaryocyte CFU (CFU-GEMM) (85 +/- 4 versus 90 +/- 1, p < or = .1) and BFU-E (90 +/- 5 versus 92 +/- 5, p < or = .1). SCF induces a dose-dependent, statistically significant enhancement of colony formation by CD34+, mafosfamide-treated cells. As shown by single colony transfer experiments, mafosfamide-resistant clones promoted by SCF have a significantly higher replating capacity as compared with mafosfamide-resistant clones grown without SCF.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1993

Autologous transplantation for chronic myelogenous leukemia with mafosfamide-treated marrow.

Ten adult patients with Ph-positive chronic myelogenous leukemia (CML) received autologous bone marrow transplantation (ABMT) using marrow treated ex vivo with mafosfamide. At the time of ABMT, six patients were in chronic phase and four in accelerated phase. Seven of ten patients reported herein were selected on the basis of a previous laboratory assessment of the numbers of normal and leukemic stroma-adherent progenitor cells within mafosfamide-treated marrow. Only patients showing > or = 50% Ph-negative stroma-adherent progenitor cells within mafosfamide-treated marrow were considered eligible for autografting. In nine out of ten evaluable patients, the median time to achieve 500 neutrophils/microliters was 32 days (range: 25-72). A platelet count of 2 x 10(4)/microliters was achieved at a median of 40 days (range: 27-97). Six out of nine analyzable patients engrafted Ph-negative. The median duration of the Ph-negative hematopoiesis, confirmed also by Southern blot analysis, was 6.5 months (range: 4-30). A good correlation was evident between the results of the in vitro preharvest screening test and the in vivo occurrence of normal hematopoiesis post-transplant. Two patients who showed 75% and 89% Ph-negative stroma-adherent progenitors engrafted Ph-positive, whereas four out of five evaluable patients who had 100% Ph-negative stroma-adherent progenitors engrafted Ph-negative. After a median follow-up of 16 months (range: 3-31), five patients evolved into blast crisis, three are alive in hematologic and cytogenetic relapse, and one died without evolving into blast crisis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Biological and chemical selection of Ph-negative clones.

Chronic myelogenous leukemia (CML) is a clonal disorder of the hematopoietic stem cell characterized by the co-existence of Philadelphia-negative with Ph-positive progenitors. CML progenitor cells have been shown to be defective in adherence to marrow stroma. The present study investigated at the cytogenetic level marrow-derived CML clonogenic cells generated from the stroma-adherent cell fraction. Mononuclear marrow cells from CML patients (n = 20) were incubated with mafosfamide (100 micrograms/ml) or control medium, seeded onto marrow stromal layers, and allowed to adhere (2 h, 37 degrees C). Following a short-term (3 days) liquid culture, the cells were harvested, incorporated in methylcellulose, and individual colonies were analyzed by single colony karyotyping. On direct cytogenetic analysis, the overall mean (+/- SD) percentage of Ph-negative metaphases was 9 +/- 20%. The mean (+/- SD) percentages of Ph-negative colonies grown from the stroma-adherent and the stroma-adherent mafosfamide-treated fraction were 41 +/- 32% and 62 +/- 40% (p < or = .005), respectively. Single colony transfer experiments revealed that 50 +/- 13% stroma-adherent and 70 +/- 24% stroma-adherent mafosfamide-treated progenitors gave rise to secondary colonies. In conclusion, the present data demonstrate the possibility to select Ph-negative clones that: 1) have a maintained capability of stroma adherence; 2) are mafosfamide resistant; and 3) have high-replating potential.

Cell Adhesion↗
PubMed1993

Fractionation of chronic myelogenous leukemia marrow cells by stroma adherence: implications for marrow purging.

Chronic myelogenous leukemia (CML) progenitor cells have been shown to be defective in their ability to adhere to marrow stroma. It was the aim of the present study to investigate at the cytogenetic level marrow-derived CML clonogenic cells fractionated on the basis of their ability to adhere to preformed, allogeneic, normal marrow-derived stromal layers. Mononuclear marrow cells from CML patients (n = 15) were incubated with mafosfamide (100 micrograms/ml) or control medium, seeded onto marrow stromal layers and allowed to adhere (3 hrs, 37 degrees C). Following a short-term liquid culture, the different cell fractions were harvested and incorporated in methylcellulose cultures. CFU-GM grown from these cultures were analyzed by single colony karyotyping. On direct cytogenetic analysis, the overall mean (+/- SD) percentage of Ph-negative metaphases was 7 +/- 20%. Following stroma adherence and shortterm suspension culture, the mean (+/- SD) percentages of Ph-negative clones were as follows: 33 +/- 25% for adherent CFU-GM, 59 +/- 40% for adherent, mafosfamide-treated CFU-GM, 12 +/- 16% for non-adherent CFU-GM, and 32 +/- 26% for non-adherent-mafosfamide-treated CFU-GM. If only the patients showing a percentage of Ph-negative clones > or = 20% were included in this analysis, the mean (+/- SD) percentages of Ph-negative clones were 47 +/- 19% for adherent CFU-GM, and 81 +/- 21% for adherent-Mafosfamide-treated CFU-GM. In contrast, the majority of pH-positive CFU-GM were detected within the stroma non-adherent cell fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Marrow Cells↗
PubMed1993

Adherence of human monocytes to haemodialysis membranes.

In the present study we evaluated spontaneous and stimulated adherence of human monocytes to regenerated cellulose and polyacrylonitrile (AN69) membranes. Spontaneous adherence at 60 min was significantly higher for regenerated cellulose (28 +/- 2%, P < 0.001) than for AN69 (11 +/- 2) membranes. Stimuli such as bacterial lipopolysaccharide, TNF alpha, interleukin-1 and -6 as well as platelet-activating factor, but not IL-4, significantly enhanced adherence at 60 min to AN69 (28 to 30%). In contrast, adherence was not further inducible in the presence of regenerated cellulose. Both spontaneous and cytokine/bacterial lipopolysaccharide-stimulated adherence were significantly reduced by SDZ-63072, a specific platelet-activating factor receptor antagonist. This difference in sensitivity of monocyte adherence reflects probably the intrinsic ability of regenerated cellulose to provide maximal spontaneous monocyte adhesion. These data suggest that PAF may act as an adherence mediator. This is in line with the ability of regenerated cellulose to directly stimulate monocytes to synthesize platelet-activating factor and with the ability of cytokines and bacterial lipopolysaccharide to stimulate its synthesis. Although AN69 has a low adherence potential, bacterial lipopolysaccharide or cytokines may blunt the biocompatibility of this membrane.

Cell Adhesion↗
PubMed1993

Counterflow centrifugal elutriation: present and future.

Counterflow centrifugal elutriation (CCE) has been proposed as a method for separating heterogeneous cell populations into distinct subpopulations on the basis of different sedimentation characteristics, without impairment of cell function or yield. The advantages of this technique are the high recovery and viability of fractionated cells and the rapidity and reproducibility of results. CCE alone or in combination with other separation methods can provide homogeneous populations of cells for further investigations. Recently, CCE has been employed in clinical studies aimed at preventing GVHD in BMT recipients by depleting lymphocytes prior to BM infusion. Furthermore, ongoing studies are concentrating on the use of negative selection procedures on the fractions currently excluded from the graft with the purpose of adding these depleted fractions to the graft preparation to augment the number of stem cells, accessory cells and unselected lymphocyte subsets. In the experimental field, CCE combined with negative and positive selection techniques may be useful in the study of hematopoiesis by separating 'pure' stem cell populations from more committed hematopoietic progenitors. We review here the present and possible future applications of elutriation in the clinical and experimental field.

Cell Separation↗
PubMed1992

Use of recombinant human granulocyte-macrophage colony-stimulating factor in patients with lymphoid malignancies transplanted with unpurged or adjusted-dose mafosfamide-purged autologous marrow.

The neutropenia-related morbidity and mortality occurring after autologous bone marrow transplantation (ABMT) is increased by marrow purging procedures. While phase I through III clinical trials showed the enhancing activity of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on neutrophil recovery after ABMT with unpurged marrow, controversial results have been reported when purged marrow was used. Therefore, it was the aim of the present study to evaluate the efficacy of rhGM-CSF administration in a group of patients (n = 15) with lymphoid malignancies transplanted in complete remission with mafosfamide-purged (n = 10) or unpurged (n = 5) marrow. Mafosfamide concentrations used for marrow purging were evaluated on an individual basis by means of a recently described technique that destroys the granulocyte-macrophage (granulocyte-macrophage colony-forming units [CFU-GM]) compartment, but spares 50% of the more primitive stroma adherent colony-forming cells (CFU-Blast). rhGM-CSF (10 micrograms/kg/d) was started within 24 hours of ABMT and administered in a 4-hour infusion daily until the absolute neutrophil count (ANC) reached 500 x 10(6)/L and then for 7 more days. Patients receiving mafosfamide-purged or unpurged marrow failed to show any difference in terms of median number of days required to achieve an ANC > or = 500 x 10(6) (13 v 14.0, P > .4) cells/L. As compared with retrospective controls, granulocytic recovery was reduced by a median time of 11 (P < or = .0005) and 5 (P < or = .0005) days for patients grafted with purged and unpurged marrow, respectively. The number of CFU-GM (mean +/- SD) infused per kilogram of body weight was significantly lower in patients who received purged autografts as compared with those receiving unpurged autografts (0.85 +/- 0.79 x 10(4) v 15.7 +/- 9.2 x 10(4), P < or = .0005). The dose of CFU-GM progenitors infused per kilogram of body weight did not correlate (r = .031, P > .05) with the time required to reach an ANC > or = 500 x 10(6) cells/L. The number of CFU-Blast (mean +/- SD) infused per kilogram of body weight was not significantly different between patients who received purged or unpurged autografts (5.05 +/- 2.51 x 10(3)/kg v 6.18 +/- 2.66 x 10(3)/kg, P < or = .375). A statistically significant correlation (r = -.658, P < or = .05) was observed between the number of CFU-Blast infused and the number of days required to reach an ANC > or = 500 x 10(6) cells/L.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Counterflow centrifugal elutriation: experimental and clinical applications.

Counterflow centrifugal elutriation (CCE) separates mixed cell populations into distinct subpopulations, on the basis of different sedimentation characteristics, without impairment of cell function or yield. The advantages of this technique are the high recovery and viability of fractionated cells, as well as the rapidity and the reproducibility of results. CCE alone, or in combination with other separation methods, can provide homogeneous populations of cells for further investigations. Recently, CCE was employed in clinical studies aimed at preventing graft-versus-host disease in bone marrow transplant recipients, by depleting lymphocytes prior to bone marrow infusion. This article reviews the principles of elutriation and describes the possible experimental and clinical applications of this technique, which seems suitable for both peripheral blood (PB) and bone marrow (BM) separation.

Bone Marrow Transplantation↗
PubMed1992

Differential sensitivity of adherent CFU-blast, CFU-mix, BFU-E, and CFU-GM to mafosfamide: implications for adjusted dose purging in autologous bone marrow transplantation.

The availability of an in vitro assay able to detect hematopoietic progenitor cells closely related to those responsible for marrow engraftment following autologous bone marrow transplantation (ABMT) prompted us to establish a procedure aimed at maximally increasing the concentration of the cyclophosphamide derivative mafosfamide used for marrow purging. It, therefore, was the aim of the present study to investigate in a group of patients with acute nonlymphoblastic leukemia (ANLL; n = 19) and acute lymphoblastic leukemia (ALL; n = 19) in complete remission the effect of mafosfamide at the level of adherent blast colony-forming units (blast colony-forming units, CFU-Blast), as well as multipotential (granulocyte erythrocyte macrophage megakaryocyte colony-forming units, CFU-GEMM), erythroid (erythroid burst-forming units, BFU-E), and granulocyte-macrophage (granulocyte-macrophage colony-forming units, CFU-GM) progenitor cells. When nonadherent marrow mononuclear cells (MNCs) were incubated (30 min, 37 degrees C) with increasing doses of mafosfamide (30-120 micrograms/ml), a statistically significant (p less than or equal to 0.0005) dose-dependent suppression of CFU-Blast growth was observed. The mean (+/- 1 standard error of the mean [SEM]) values of 50% inhibition (ID50) of the CFU-Blast growth were not significantly different for ANLL (106 +/- 5) and ALL (107 +/- 5) patients. Analysis of CFU-Blast ID50 distribution demonstrated that ID50 ranged from 100 to 120 micrograms/ml in 17 cases (45%), whereas it ranged from 60 to 100 micrograms/ml in 12 cases and from 120 to 160 micrograms/ml in 9 cases. A statistically significant (p less than or equal to 0.05), dose-dependent suppression of colony growth from multi-potential and lineage-restricted progenitor cells was also observed. However, the value of CFU-Blast ID50 was significantly higher (p less than or equal to 0.05) than CFU-GEMM, BFU-E, and CFU-GM ID50 and ID95 values. In conclusion, our data demonstrate that: 1) the CFU-Blast assay allows to detect on an individual basis the doses of mafosfamide used for marrow purging, and 2) the concentrations of mafosfamide extrapolated by using the CFU-Blast assay are significantly higher than those obtained with the CFU-GM assay. The absence of any detrimental effect on marrow engraftment in vivo supports the safety of the CFU-Blast assay to evaluate the dose of mafosfamide used for marrow purging before ABMT.

Antineoplastic Agents↗
PubMed1991

In vitro marrow purging in chronic myelogenous leukemia: effect of mafosfamide and recombinant granulocyte--macrophage colony-stimulating factor.

Clinical and experimental evidence revealing Ph1-negative hematopoietic stem cells in the majority of chronic myelogenous leukemia (CML) patients, suggests that autologous bone marrow transplantation (ABMT) may represent a therapeutic approach for these patients. It was the aim of the present study to evaluate the efficacy of the cyclophosphamide derivative mafosfamide as a marrow purging agent in a group (n = 15) of CML patients. Chemical purging was followed by a short-term liquid culture phase supplemented with recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF). Mafosfamide (100 micrograms/ml) incubation induced a marked inhibition of progenitor cell growth, the percentages of surviving CFU-GEMM, BFU-E, and CFU-GM being 3.4, 5.4, and 4.9, respectively. At the cytogenetic level, the purging procedure failed to show any modulating effect on Ph1-negative clones in 9/15 cases. In contrast, 6/15 cases showed a significant increase in the mean (+/- SD) percentage of Ph1-negative metaphases in response to rGM-CSF (46 +/- 26, p less than or equal to 0.05), mafosfamide incubation (53 +/- 12, p less than or equal to 0.01), and the combination of mafosfamide incubation plus rGM-CSF (63 +/- 29, p less than or equal to 0.025). Immunological analysis revealed that mafosfamide incubation induced a significant enrichment of MY10 (28 +/- 9, 0.05) B73.1-positve cells (25 +/- 9, p less than or equal to 0.05). Four mafosfamide-responsive patients with CML in second chronic phase have been autografted with mafosfamide purged marrow. In all patients a Ph1-negative phase lasting 5-14 months was observed. In conclusion, it appears that (a) in a subgroup of CML patients mafosfamide purging is effective in reducing the size of the malignant clone and might induce through its cytotoxic and immune actions a modification of the balance between leukemic and normal clones, and (b) this experimental approach may be used as a screening test to select patients to undergo marrow harvest and ABMT with mafosfamide purged marrow.

Adult↗
PubMed1990

Growth of CD34+ acute myeloblastic leukemia colony-forming cells in response to recombinant hematopoietic growth factors.

In order to minimize the interactions of clonogenic cells with accessory cells and characterize the direct effect of recombinant hematopoietic growth factors (HGF) on acute myelogenous leukemia colony-forming cells (AML-CFU), the response of CD34+ AML-CFU to individual or combined recombinant HGF, i.e., interleukin-1 (IL-1), interleukin-3 (IL-3), interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), and macrophage colony-stimulating factor (M-CSF), was studied in 10 patients and compared with the growth response obtained from unfractionated marrow cells. IL-3 and GM-CSF had a similar stimulating activity on AML-CFU growth. G-CSF resulted the most efficient stimulus for colony formation and was additive or synergistic with IL-3 and GM-CSF, M-CSF, used alone, had a negligible stimulating activity. When CD34+ cells were used, IL-1 by itself had a low stimulating activity and displayed little or no synergy with IL-3, GM-CSF, and G-CSF. On the contrary, when unfractionated cells were used, IL-1 was very effective in inducing AML-CFU formation and was markedly synergistic with IL-3 and GM-CSF. These results show that IL-1-induced leukemic colony formation is prevalently mediated by accessory cells. IL-6 supported AML-CFU growth in seven of 10 cases, thus showing a direct effect on CD34+ leukemic cells, and enhanced the growth of IL-3-(+47 to +167%) and GM-CSF-dependent (+60 to +110%) AML-CFU. Recloning studies of single colonies demonstrated that primary CD34+ AML-CFU, stimulated by IL-3 and GM-CSF, generated secondary and tertiary colonies, whereas primary AML-CFU stimulated by G-CSF and IL-6 failed to give rise to secondary colonies, thus indicating a complete suppression of self-renewal. Sequential recloning of colonies grown in the presence of IL-3 + IL-6 demonstrated that addition of IL-6 and IL-3-containing plates resulted in a nearly complete suppression of self-renewal. In conclusion, these results demonstrate the heterogeneity of the CD34+ leukemic cell fraction and indicate the existence of complex regulatory events at the level of CD34+ leukemic cells. Data obtained from recloning experiments are of therapeutic interest in view of the clinical application of HGFs in the treatment of myeloid leukemias.

Adult↗