Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bone Marrow Purging”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed1994

Interleukin-2 activation of human bone marrow in long-term cultures: an effective strategy for purging and generation of anti-tumor cytotoxic effectors.

Our previous studies have shown that IL-2 activated bone marrow cells develop potent tumoricidal activity in vitro and in vivo. With the dual aim of in vitro purging and generation of effectors which could mediate graft-versus-leukemia effects in vivo, IL-2 activation of human bone marrow in long-term cultures (LTC) was tested. Marked cytotoxicity was seen against A375 (melanoma), K562 (CML) and Daudi (lymphoma) cell lines in IL-2 (1000 U/ml) stimulated cultures. Hematopoietic progenitor cell number in these cultures was assessed by day 14 clonogenic assays. In 1-week-old IL-2 stimulated cultures a higher number of clonogenic cells was seen than control LTCs without IL-2. However, thereafter accelerated decrease in the number of clonogenic cells was seen in IL-2 cultures. In vitro purging efficacy was tested by elimination of A375 and K562 cells mixed with normal marrow at 1:10 and 1:100 ratios and co-cultured for 10 days. In IL-2 stimulated cultures, A375 cells capable of proliferation were not detectable at both mixing ratios. K562 elimination was complete only at 1:100 ratio. After 10 days in culture, no Ph1-positive metaphases were seen in IL-2 stimulated BM cultures of 4 patients with CML. These results indicate that IL-2 activation of BM in 1-2 week cultures can lead to generation of marked anti-tumor cytotoxicity and effective in vitro purging in a variety of tumor types.

Bone Marrow↗
PubMed2004

An update on the role of high-dose therapy with autologous or allogeneic stem cell transplantation in mantle cell lymphoma.

PURPOSE OF REVIEW: Early trials of high-dose therapy with autologous stem cell transplantation in mantle cell lymphoma were discouraging, with no clear survival advantage attributable to the procedure. Most early series were plagued by small numbers, retrospective designs, and short follow-up. Also, until recently, allogeneic stem cell transplantation was not an option for most mantle cell lymphoma patients who were too old or infirm to tolerate standard conditioning regimens. RECENT FINDINGS: New advances in allogeneic transplantation, particularly reduced-intensity conditioning regimens, have increased the availability of this procedure to patients with mantle cell lymphoma. New evidence has emerged during the last several years that suggests autologous stem cell transplantation in first complete remission may provide a survival advantage over conventional chemotherapy in patients with mantle cell lymphoma. Additionally, investigational strategies such as in vivo purging with rituximab and the use of radioimmunotherapy in conditioning regimens may further increase response rates and, hopefully, survival in mantle cell lymphoma patients. Finally, recent studies suggest the existence of a graft-versus-lymphoma effect in mantle cell lymphoma providing strong scientific rationale for the possible curative potential of allogeneic stem cell transplantation in this disease. SUMMARY: This review focuses on recent advances in allogeneic and autologous transplantation for mantle cell lymphoma. Particular emphasis is placed on the role of autologous transplantation in first complete remission, the role of in vivo purging with rituximab, the utility of radioimmunotherapy and, finally, the evolving strategy of reduced-intensity allogeneic stem cell transplantation.

Alemtuzumab↗
PubMed2004

[Mechanisms of dibutyl phthalate to purge leukemic cells].

OBJECTIVE: To determine the mechanism of dibutyl phthalate (DBP) to purge leukemic cells by inducing apoptosis. METHODS: The effects of DBP on the intracellular free Ca2+ concentration ([Ca2+]i) of leukemic cells were measured by Fura-2AM method. The effects of DBP on the protein expression of c-myc and bcl-2 genes of leukemic cells were measured by immunohistochemical assay. RESULTS: DBP elicited an intracellular Ca2+ redistribution and a potent extracellular calcium influx in leukemic cells. It also down-regulated the protein expression of c-myc and bcl-2 genes. CONCLUSION: DBP can purge leukemic cells in vitro by increasing [Ca2+]i in cells to initiate apoptosis and down-regulate bcl-2 and c-myc proto-gene expression to promote the cell apoptosis.

Bone Marrow Purging↗
PubMed1999

Enhanced cytotoxic interaction between 5-fluorouracil and 4-hydroperoxycyclophosphamide against L1210 murine leukemic cells: applicability to ex vivo purging.

Eradication of contaminated tumor cells in bone marrow is a matter of utmost concern in the setting of autologous bone marrow transplantation. 4-Hydroperoxycyclophosphamide (4-HC) is often used for ex vivo chemical purging of contaminated tumor cells in bone marrow. The marrow from patients pretreated with 5-fluorouracil (5-FU) is enriched with multifactor-responsive high proliferative potential colony-forming cells. To develop an efficient ex vivo chemical purging system, we evaluated interaction between 4-HC and 5-FU. We investigated the antitumor effect of cyclophosphamide, a mother compound of 4-HC, and 5-FU against L1210 ascites tumor in B6D2F1 mice. The median lifespan of the mice treated with 4-HC or 5-FU alone was 8 and 12 days, respectively. The combination of both drugs significantly extended the median lifespan to 18.5 days. The median effect plot analysis indicated a synergistic cytotoxic interaction between 5-FU and 4-HC in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl terazolium bromide (MTT) assay. Clonogenic assay also showed that combination of 4-HC and 5-FU significantly reduced L1210 leukemic colonies to 20% of untreated control. Bone marrow cells from the mice treated with 5-FU at 150 mg/kg body weight was resistant to 4-HC at concentrations as high as 0.2 microgram/ml, which was more than 70% inhibitory concentration for colony formation in L1210 leukemic cells. Findings suggest that sequential treatment with in vivo 5-FU followed by ex vivo 4-HC could selectively enhance antitumor effects of 4-HC in tumor cells remaining in bone marrow.

Animals↗
PubMed2001

Ifosamide, epirubicin and granulocyte colony-stimulating factor: a regimen for successful mobilization of peripheral blood progenitor cells in patients with multiple myeloma.

In general, the mobilization of peripheral blood progenitor cells (PBPC) in multiple myeloma (MM) patients is poor and is achieved in most cases by combined cyclophosphamide and G-CSF. This study was performed to examine the efficacy of combined ifosfamide/epirubicine and G-CSF for PBPC mobilization and purging. Sixteen patients suffering from multiple myeloma in stage II/A and III/A according to Durie and Salmon underwent chemotherapy consisting of a total of three cycles of ifosfamide (3 g/m(2) on days 1 and 2 and epirubicine 80 mg/m(2) on day 1) and G-CSF (10 or 20 microg/kg body weight (BW) daily until harvesting). PBPC harvesting was performed after the first and third cycle of chemotherapy. The median number of PBPC after the first cycle of chemotherapy was 7.79 x 10(6) CD34+ cells/kg BW (ranging from 0.94-26.36 x 10(6)) and 6.38 x 10(6) CD34+ cells/kg BW (ranging from 0.79-29.31 x 10(6)) after the third cycle of chemotherapy. Clinical re-evaluation after three cycles of chemotherapy showed 13 (81 per cent) patients in partial remission (PR), two (12 per cent) in complete remission (CR) and one (6.25 per cent) in stable disease (SD). No major side-effects were observed, six patients developed hematological toxicity stage IV WHO for a median of 3.9 days but no serious infection episodes occurred. Combined ifosfamide/epirubicin and standard G-CSF is able to mobilize sufficient PBPC without serious side-effects for patients with MM and for purging procedures resulting in a high proportion of complete remissions after tandem high-dose melphalan chemotherapy.

Adult↗
PubMed1999

Autologous transplantation of chemotherapy-purged PBSC collections from high-risk leukemia patients: a pilot study.

We have recently demonstrated that the combination of the alkylating agent nitrogen mustard (NM) and etoposide (VP-16) is capable of eliminating, ex vivo, leukemic cells contaminating PBSC collections and this is associated with a significant recovery of primitive and committed hematopoietic progenitor cells. Based on these data a pilot study on autologous transplantation of NM/VP-16 purged PBSC for high-risk leukemic patients was recently initiated. Twelve patients (seven females and five males) with a median age of 46 years (range 18-57) have been treated. Two patients had acute myeloblastic leukemia (AML) resistant to conventional induction treatment, four patients had secondary AML in I complete remission (CR), one patient was in II CR after failing a previous autologous BM transplantation, while two additional AML individuals were in I CR achieved after three or more cycles of induction treatment. Two patients with high-risk acute lymphoblastic leukemia (ALL) in I CR and one patient with mantle cell lymphoma and leukemic dissemination were also included. Eight patients showed karyotypic abnormalities associated with a poor clinical outcome. The mobilizing regimens included cytosine arabinoside and mitoxantrone with (n = 6) or without fludarabine (n = 3) followed by subcutaneous administration of G-CSF (5 microg/kg/day until the completion of PBSC collection) and G-CSF alone (n = 3) (15 microg/kg/day). A median of two aphereses (range 1-3) allowed the collection of 7.2 x 10(8) TNC/kg (range 3.4-11.5), 5 x 10(6) CD34+ cells/kg (range 2.1-15.3) and 9.2 x 10(4) CFU-GM/kg (0.3-236). PBSC were treated with a constant dose of 20 microg of VP-16/ml and a median individual-adjusted dose (survival < or = 5% of steady-state BM CFU-GM) of NM of 0.7 microg/ml (range 0.25-1.25). Eleven patients were reinfused after busulfan (16 mg/kg) and Cy (120 mg/kg) conditioning with a median residual dose of 0.3 x 10(4) CFU-GM/kg (0-11.5). The median time to neutrophil engraftment (>0.5 x 10(9)/l) for evaluable patients was 25 days (range 12-59); the median time to platelet transfusion independence (>20 and >50 x 10(9)/l) was 40 days (18-95) and 69 days (29-235), respectively. Hospital discharge occurred at a median of 25 days (18-58) after stem cell reinfusion. Four individuals are alive in CR (n = 3) or with residual nodal disease (n = 1 lymphoma patient) with a follow-up of 32, 26, 3 and 14 months, respectively. Seven patients died due to disease progression or relapse (n = 5) or extrahematological transplant toxicity (n = 2). Our data suggest that pharmacological purging of leukapheresis collections of leukemic patients at high-risk of relapse is feasible and ex vivo treated cells reconstitute autologous hematopoiesis.

Acute Disease↗
PubMed2000

Selective elimination of leukemic CD34(+) progenitor cells by cytotoxic T lymphocytes specific for WT1.

Hematologic malignancies such as acute and chronic myeloid leukemia are characterized by the malignant transformation of immature CD34(+) progenitor cells. Transformation is associated with elevated expression of the Wilm's tumor gene encoded transcription factor (WT1). Here we demonstrate that WT1 can serve as a target for cytotoxic T lymphocytes (CTL) with exquisite specificity for leukemic progenitor cells. HLA-A0201- restricted CTL specific for WT1 kill leukemia cell lines and inhibit colony formation by transformed CD34(+) progenitor cells isolated from patients with chronic myeloid leukemia (CML), whereas colony formation by normal CD34(+) progenitor cells is unaffected. Thus, the tissue-specific transcription factor WT1 is an ideal target for CTL-mediated purging of leukemic progenitor cells in vitro and for antigen-specific therapy of leukemia and other WT1-expressing malignancies in vivo.

Adult↗
PubMed2002

In vivo purging and relapse prevention following ASCT.

The combination of high-dose chemotherapy and autologous stem cell transplantation (ASCT) is a potentially curative therapy for patients with relapsed chemosensitive non-Hodgkin's lymphoma (NHL) and is increasingly being considered as a first-line treatment for NHL patients with poor prognosis or poor outcomes from chemotherapy. However, there is a degree of relapse following the latter which is associated with high levels of tumour cell contamination of the stem cells and/or the presence of residual malignant cells in the host following chemotherapy. Reducing the rate of relapse can be achieved by pre-transplant purging of the stem cell graft followed by post-transplant maintenance to minimise residual disease. Various methods of in vitro purging have been shown to reduce, but not eliminate, the level of stem cell contamination and invariably result in a reduced harvest. To date, this has been reflected in disappointing outcomes for the patient. In contrast, in vivo purging with rituximab during the process of stem cell mobilisation and collection does not adversely affect the yield or function of stem cells and shows a significant improvement in the level of tumour cell contamination as measured by bcl-2 clearance. The relapse potential from residual malignant cells in the host can be addressed by a programme of post-transplant rituximab maintenance therapy. In one study 17 patients with follicular lymphoma who underwent ASCT with in vivo rituximab-purged stem cells, followed by rituximab maintenance, have all remained in complete response at a median follow-up of 12.4 months. The optimum in vivo rituximab purging protocol and the precise effect in terms of overall and disease-free survival are currently being evaluated but appear to present an attractive first-line alternative for NHL patients with poor prognosis or poor outcomes following chemotherapy.

Antibodies, Monoclonal↗
PubMed2006

Randomised comparison of two B-cell purging protocols for patients with B-cell non-Hodgkin lymphoma: in vivo purging with rituximab versus ex vivo purging with CliniMACS CD34 cell enrichment device.

We investigated the feasibility, safety and efficacy of two B-cell purging methods in patients with CD20+ non-Hodgkin lymphoma (NHL) receiving autologous stsem cell transplantation. Myeloid and immune recoveries between the methods were compared. Twenty-seven patients were randomised to either in vivo purging with rituximab or ex vivo purging by CD34+ cell selection. Both purging methods were efficient at eliminating B-cells in infusates. When compared with in vivo purging, ex vivo purging was associated with CD34+ cell loss and delayed median neutrophil (10 d vs. 11 d) and platelet (12.5 d vs. 17 d) count recoveries. Lymphocyte recovery was similar in both groups, but immunoglobulin recovery was delayed after in vivo purging. Late-infectious complications were few in both arms. At a median follow-up of 27 months, 2-year probabilities of event-free survival (EFS) rates were 81% for in vivo purging and 76% for ex vivo purging (P = 0.66). When compared with 53 unpurged patients, all 27 purged patients had improved 3-year probabilities of overall survival (89% vs. 70%, P = 0.014) and a trend for improved EFS (78% vs. 57%, P = 0.075). In conclusion, although both purging methods were feasible and safe, rituximab purging was superior as it did not impair CD34+ cell mobilisation and was associated with faster myeloid recovery. Further studies are needed to determine whether rituximab purging is more effective than the use of unpurged autografts.

Adult↗
PubMed1987

Comparative cytotoxicity of various drug combinations for human leukemic cells and normal hematopoietic precursors.

The development of suitable methods for purging the malignant cells contaminating the bone marrow of patients with cancer may offer a better chance of success for autologous bone marrow transplantation. In this paper, we further describe our efforts at purging acute myelogenous leukemia cells. HL-60, a promyelocytic leukemia cell line, was used as a model. 4-Hydroperoxycyclophosphamide (4-HC), VP-16-213 (VP-16), and Adriamycin were used alone or in combination to develop the best method to purge HL-60 cells. The cytotoxicity of 29.2 micrograms/ml (100 microM) of 4-HC was 99.8 +/- 0.12% (SD) on HL-60 cells and 82.5% on colony forming units-granulocyte, macrophage. Ninety-nine % of HL-60 cells and 72.7% of colony forming units-granulocyte, macrophage were inhibited by VP-16 at a concentration of 25 micrograms/ml (42.5 microM). The cytotoxicity of 1.5 micrograms/ml (2.76 microM) of Adriamycin on HL-60 cells was 98.6 +/- 0.8% and inhibited colony forming units-granulocyte, macrophage by 50.8%. The cytotoxicity and interactions of any two drug combinations at different combination ratios and the different effect levels were quantitatively determined by median effect plot and the multiple drug effect equation (T-C. Chou and P. Talalay. Adv. Enzyme Regul. 22: 27-55, 1984). The combination of 4-HC and VP-16 at a 4-HC:VP-16 drug ratio of 1:0.342 was found to be the best for selective toxicity towards HL-60 cells and was superior to the 4-HC-Adriamycin or VP-16 Adriamycin combination for usefulness in purging bone marrow.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Immunologic purging of autologous peripheral blood stem cell products based on CD34 and CD133 expression can be effectively and safely applied in half of the acute myeloid leukemia patients.

PURPOSE: Several studies have shown survival benefit by autologous stem cell transplantation in acute myeloid leukemia (AML) after purging of grafts. This has, however, not been confirmed in randomized studies due to high toxicity of purging modalities for normal progenitor/stem cells. In this study, we investigated whether positive selection for CD34+ and/or CD133+ cells, which results in high recovery of normal progenitor/stem cells, is applicable for purging AML grafts. EXPERIMENTAL DESIGN: Positive selections of normal stem cells using CD34 and/or CD133 can be done if one or both markers are absent or have dim expression and remain so during the course of the disease. Marker expressions in newly diagnosed AML were measured with flow cytometry using a cutoff value for positivity of 1%. Stability of marker expression was studied by pairwise comparison of material at diagnosis and relapse. Leukemia associated phenotype expression was used to measure the efficacy of tumor cell reduction. RESULTS: In newly diagnosed AML (n = 165), we found no CD34 and/or CD133 expression in 32% of the cases and dim expression in 20% of the cases. No increase in the percentage of CD34+ cells (n = 44) and CD133+ cells (n = 29) was found in corresponding relapses. Positive selection using grafts contaminated with AML blasts, showing either no or dim expression of CD34 or CD133, resulted in a 3 to 4 log tumor cell reduction (n = 11) with median 50% recovery of normal stem cells. CONCLUSIONS: Purging by positive selection of CD34+ and/or CD133+ cells can safely, effectively, and reproducibly be applied in about 50% of AML cases.

AC133 Antigen↗
PubMed1999

Peripheral blood stem cell contamination in mantle cell non-Hodgkin lymphoma: the case for purging?

Intensification using peripheral blood stem cells collected after chemotherapy followed by growth factors is being increasingly investigated as an alternative to conventional chemotherapy for mantle cell non-Hodgkin lymphoma. We investigated 14 grades III-IV, t(11;14)-positive cases for contamination of PBSC collected after a polychemotherapy regimen followed by G-CSF. Patients were first treated with a polychemotherapy regimen. There were four CR, seven PR, two refractory and one early death. Seven patients have been transplanted, in whom PBSC were mobilized, using either cyclophosphamide/VP16 or Dexa-BEAM followed by G-CSF. For all patients, whether actually autografted or not, PB cells were tested at the time of regeneration on G-CSF after the first polychemotherapy or after the mobilizing regimen. PCR evaluation of contamination was performed first by a semi-quantitative approach, using serial dilutions of initial DNA, then confirmed using a limiting-dilution analysis. Two patients were not informative (one early death and one without an available molecular marker). PB cells collected at regeneration contained at least one log more lymphoma cells than steady-state blood or marrow, apart from in two cases. Moreover, where a mobilizing treatment diminished tumor burden in the patient, at the same time it increased PB contamination in most cases. We conclude that advanced mantle cell NHL appears to be largely resistant to significant in vivo purging by conventional chemotherapy. Where treatment brings benefits by reducing tumor load, it may at the same time negate it by mobilizing malignant cells into the collections used to intensify. Although the clonogenic potential of this massive infiltration is unknown (only gene marking studies could provide a definitive answer regarding the source of relapses), strategies aimed at reducing the level of contamination in the graft should be considered when designing future protocols.

Adult↗
PubMed2001

Continuous complete remission in adult patients with acute lymphocytic leukaemia at a median observation of 12 years after autologous bone marrow transplantation.

We report our long-term experience with autologous bone marrow transplantation (ABMT) for 32 adult patients with acute lymphocytic leukaemia (ALL) in second or later remission (CR), or in first CR but with high-risk. Bone marrow was purged with mafosfamide (n = 25) or with immunomagnetic beads and monoclonal antibodies (n = 7). Retrospective analysis showed that 12 out of 32 patients were in continuous complete remission (CCR) at a median of 143 months (range 66-181 months). A plateau was reached at 50 months and the disease-free and overall survival rates were both 37.5%. It was notable that durable CCR could be achieved for patients in second (three out of nine) or third (one out of six) CR. ABMT could produce durable CCR and the long-term outcome compared favourably with those reported for allogeneic transplantation.

Adolescent↗
PubMed1999

Shiga-like toxin-1 receptor on human breast cancer, lymphoma, and myeloma and absence from CD34(+) hematopoietic stem cells: implications for ex vivo tumor purging and autologous stem cell transplantation.

The ribosome-inactivating protein, Shiga-like toxin-1 (SLT-1), targets cells that express the glycolipid globotriaosylceramide (CD77) on their surface. CD77 and/or SLT-1 binding was detected by flow cytometry and immunocytochemistry on lymphoma and breast cancer cells recovered from biopsies of primary human cancers as well as on B cells or plasma cells present in blood/bone marrow samples of multiple myeloma patients. Breast cancer cell lines also expressed receptors for the toxin and were sensitive to SLT-1. Treatment of primary B lymphoma, B-cell chronic lymphocytic leukemia, and myeloma B or plasma cells with SLT-1-depleted malignant B cells by 3- to 28-fold, as measured by flow cytometry. Depletion of myeloma plasma cells was confirmed using a cellular limiting dilution assay followed by reverse transcriptase-polymerase chain reaction analysis of clonotypic IgH transcripts, which showed a greater than 3 log reduction in clonotypic myeloma cells after SLT-1 treatment. Receptors for the toxin were not detected on human CD34(+) hematopoietic progenitor cells (HPC). HPC were pretreated with a concentration of SLT-1 known to purge primary malignant B cells and cultured for 6 days. The number of HPC was comparable in toxin-treated and untreated cultures. HPC were functionally intact as well. Colony-forming units (CFU) were present at an identical frequency in untreated and SLT-1 pretreated cultures, confirming that CFU escape SLT-1 toxicity. The results suggest the ex vivo use of SLT-1 in purging SLT-1 receptor-expressing malignant cells from autologous stem cell grafts of breast cancer, lymphoma, and myeloma patients.

Antibodies, Monoclonal↗
PubMed2000

CD34 selection as a stem cell purging strategy for neuroblastoma: preclinical and clinical studies.

BACKGROUND: The suitability of CD34 selection for purging peripheral blood progenitor cells (PBPC) collected from patients with neuroblastoma (NB) has been called into question, largely because of reports of detection of low levels of CD34 on the surface of some NB cell lines and tumors. PROCEDURE: We used three approaches to address the issue of purging of NB from stem cell specimens and possible labeling of NB: 1) Flow cytometric detection of CD34 on NB cell lines. We assessed CD34 expression using a panel of anti-CD34 monoclonal antibodies (MoAbs) including 9C5, 12.8, and QBend10 and showed no increase in labeling over secondary-only control. 2) Spiking experiments with the Isolex 50 system. NB cell lines were used to contaminate aliquots of PBPC collections, after which the products were purified using the Isolex 50. Purging of NB was assessed by quantitative multiplex RT-PCR (TaqMan system) using a tumor-specific transcript, GAGE. We demonstrated >2 logs of tumor cell depletion from these specimens. 3) Analysis of clinical specimens. PBPC pre- and post-CD34 selection were analyzed from patients treated on the CHP-594 transplant trial. RESULTS: In nine specimens selected using the Ceprate LC CD34 selection system where tumor was detectable by immunocytochemistry preselection, we observed >2.4 to >4.6 logs of NB purging after selection. We then analyzed 23 aliquots of PBPC infused into patients post-CD34 selection and compared them to the product preselection; 20/23 specimens showed depletion of NB, although some level of GAGE message was observed in most post-CD34 selection specimens. CONCLUSION: These data show that purging of NB from PBPC specimens using CD34 selection is feasible, yielding infused products that are negative at the level of ICC but often positive at the level of RT-PCR.

Antigens, CD34↗
PubMed1994

Effects of neocarzinostatin upon the development of tumors from murine neuroblastoma cells.

The use of differentiation-inducing agents has been proposed for the purging of bone marrow and for the treatment of minimal residual disease prior to autologous bone marrow transplantation in patients with metastatic neuroblastoma. The present studies examine the effects of the enediyne differentiation inducer neocarzinostatin (NCS) on tumor development from subcutaneous implants of murine (Neuro-2A) neuroblastoma cells. Prior in vitro treatment with NCS results in a concentration- and drug exposure time-dependent decrease in the incidence of tumors from subcutaneously implanted cells. In vivo treatment results in a dose-dependent decrease in the rate of tumor growth. These results imply that enediynes such as NCS may be useful in ex vivo purging regimens and in in vivo treatment of microscopic residual disease in patients with neuroblastoma.

Animals↗
PubMed2000

Pulsed electric fields for selection of hematopoietic cells and depletion of tumor cell contaminants.

Purging of tumor cells and selection of stem cells are key technologies for enabling stem cell transplantation and stem cell gene therapy. Here we report a strategy for cell selection based on physical properties of the cells. Exposing cells to an external pulsed electric field (PEF) increases the natural potential difference across the cell membrane until a critical threshold is reached and pore formation occurs, resulting in fatal perturbation of cell physiology. Attaining this threshold is a function of the applied field intensity and cell size, with larger cells porated at lower field intensities than smaller cells. Since hematopoietic stem cells are smaller than other hematopoietic cells and tumor cells, we found that exposure of peripheral blood mononuclear cells (PBMCs) to PEFs caused stepwise elimination of monocytes without affecting the function of smaller lymphocyte populations. Mobilized peripheral blood exposed to PEFs was enriched for CD34+/CD38- cells and stem cell function was preserved. Furthermore, PEF treatment was able to selectively purge blood preparations of tumor cells and eradicate transplantable tumor.

ADP-ribosyl Cyclase↗