ALDEFLUOR™ Assay Buffer

Educational resources:

•  VIDEO: ALDEFLUOR™: Detect Normal and Cancer Precursor Cells
•  WEBINAR: ALDEFLUOR™ and Cancer Stem Cells
•  TECH BULLETIN: Identification of ALDH-Expressing Cancer Stem Cells using ALDEFLUOR™ (Catalog #29937)
•  TECH BULLETIN: Immunophenotyping of ALDEFLUOR™-Reacted Cells
•  TECH BULLETIN: Identification of viable stem and progenitor cells with ALDEFLUOR™ (Catalog #28728)
•  TECH BULLETIN: A guide to identification of stem cells without antibodies (Catalog #29140)
•  BROCHURE: ALDEFLUOR™ Selected Cancer References
•  VIDEO: The Basic FACS About ALDEFLUOR™ - A Guide To Successful Flow Cytometry Analysis
•  TECH BULLETIN: ALDEFLUOR™ Assay Optimization

MSDS:

•  01701-MSDS.pdf

FAQS:

• 
  ALDEFLUOR™ PROCEDURE: REAGENT ACTIVATION AND STORAGE
  
  
  • Q. THE REAGENTS IN THE KIT WERE FROZEN WHEN I RECEIVED IT. WILL THIS CAUSE A PROBLEM?
    A. No, the reagents in the kit are stable to freezing. Assay performance will not be affected.
  • Q. IS IT ACCEPTABLE FOR ACTIVATION OF THE ALDEFLUOR™ REAGENT TO EXCEED 30 MINUTES?
    A. Yes, as long as room temperature does not exceed 22°C, the reaction can proceed for up to 6 hours with no effect on the assay.
  • Q. CAN I SPEED UP THE ACTIVATION REACTION BY INCUBATING AT 37°C?
    A. This is not recommended. Incubation of the activation reaction at 37°C will not significantly speed up the reaction, and degradation of the activated substrate will occur more quickly at higher temperatures.
  • Q. WILL THE ACTIVATION REACTION PROCEED AT REFRIGERATOR (2 - 8°C) TEMPERATURES?
    A. The ALDEFLUOR™ reagent will remain active for 1 week when stored at 2 - 8°C. For longer storage, divide the remaining reagent into aliquots and store at or below -20°C. Activated ALDEFLUOR™ reagent is stable for 1 year when stored frozen.
  • Q. HOW SHOULD I STORE THE ALDEFLUOR™ REAGENT AFTER IT IS ACTIVATED?
    A. The ALDEFLUOR™ reagent will remain active for 1 week when stored at 2 - 8°C. For longer storage, divide the remaining reagent into aliquots and store at or below -20°C. Activated ALDEFLUOR™ reagent is stable for 1 year when stored frozen.
  
  ALDEFLUOR™ PROCEDURE: STAINING REACTION
  
  
  • Q. WHY MUST THE ALDEFLUOR™ ASSAY BUFFER BE ADDED?
    This assay has been optimized for detecting stem and progenitor cells by addition of the ALDEFLUOR™ assay buffer. Stem and progenitor cells have high ABC transporter activity and BAAA is a substrate for these efflux pumps. The assay buffer incorporates an efflux pump inhibitor to produce optimal discrimination of the ALDHbr cells and to maximize fluorescent signal stability. We thus recommend that cells be kept on ice and that the ALDEFLUOR™ assay buffer be used throughout all procedures performed after ALDH staining. Not using the assay buffer produces a proportionate loss in the assay signal, depending on the time and temperature at which the stained cells are held.
  • Q. IS IT ACCEPTABLE FOR THE STAINING REACTION TO EXCEED 30 MINUTES?
    A. It depends on the cell type. With hematopoietic cells the reaction time can be up to 1 hour at 37°C with no effect on the fluorescence intensity. Incubation periods exceeding 1 hour may lead to an weaker signal and/or higher background. For nonhematopoietic cells optimal incubation times may be different. For example, for the human mammary epithelial SKBR3 cell line, the optimal incubation time was 45 minutes in experiments done at STEMCELL. It is recommended to test different incubation times and determine the optimal incubation time for different cell types.
  • Q. WILL THE STAINING REACTION PROCEED AT REFRIGERATOR (2 - 8°C) TEMPERATURES?
    A. Yes, but full staining will take at least 3 - 4 hours. The staining reaction can continue for up to 24 hours at 2 - 8°C without any effect on the assay.
  • Q. CAN I ADD ANY OTHER EFFLUX INHIBITORS TO THE ALDEFLUOR™ ASSAY BUFFER?
    A. Yes. To prevent efflux of the activated ALDEFLUOR™ reagent and the reaction product, the following may be added individually or in combination. These reagents may also improve discrimination of the ALDHbr population, but results will vary by sample type.
    • 50 - 100 µM verapamil
    • 2.5 mM probenecid
    • 100 mM 2-deoxy-D-glucose
    • 1 mg/mL sodium azide (0.1%) Note: Sodium azide may be toxic to cells. Do not use if cellular function assays are to be performed after the ALDEFLUOR™ assay.
    Note: Ice is the universal efflux inhibitor. Keep all ALDEFLUOR™-reacted samples on ice or at 2 - 8°C as much as possible.
  • Q. CAN I STAIN THE CELLS AT A CONCENTRATION HIGHER THAN 1 X 10⁶ CELLS/ML?
    A. Increasing the concentration of cells up to 5-fold the recommended concentration should have no effect on performance of the assay when using human blood cells. Increasing cell concentrations greater than 5-fold the recommended concentration will decrease assay signal and thereby decrease discrimination of the ALDHbr population. However, different cell types may produce different results. Cell titration experiments may be necessary to determine the optimal cell concentration for different cell types. To stain large number of cells it may be better to increase the sample and reagent volume.
  
  DETECTING HEMATOPOIETIC CELLS
  
  
  • Q. WHAT ANTICOAGULANTS CAN BE USED TO COLLECT SAMPLES?
    A. Optimal assay performance can be achieved with peripheral blood and leukapheresis samples anticoagulated with acid-citrate dextrose (ACD), ethylenediaminetetraacetic acid (EDTA), or sodium heparin. Bone marrow should be anticoagulated with sodium heparin. Cord blood units may be collected into citrate phosphate dextrose anticoagulant.
  • Q. DO ERYTHROCYTES (RED BLOOD CELLS) INTERFERE WITH THE ASSAY?
    A. The large number of erythrocytes present in peripheral blood, apheresis collections, bone marrow, and umbilical cord blood samples can compete with stem/progenitor cells for the ALDEFLUOR™ substrate. For optimal assay performance, lyse the erythrocytes by treating the samples with ammonium chloride. The ratio of lysis buffer to cell numbers or blood volume must be optimized (10 to 40 parts buffer to sample), and the time (10 - 30 minutes) and temperature (RT or 2 - 8°C) of incubation must be carefully controlled for each lysis buffer and sample type.
  • Q. WHAT SOLUTIONS CAN BE USED TO LYSE ERYTHROCYTES?
    A. Optimal erythrocyte lysis can be achieved with buffers containing:
    • Ammonium chloride (e.g. 0.17 M NH4CI, 10 mM Tris HCI, 0.25 mM EDTA),
    • 1X ABC Lysis Buffer (eBioscience, San Diego, CA)
    • VitaLyse® (BioE, St Paul, MN).
    We do not recommend use of the following or any other solution that contains a fixative, as these will render the cells nonviable:
    • CyLyse® (Partec GMBH, Munster, Germany),
    • FACS™ Lysing solution (BD Biosciences, San Jose, CA.)
  • Q. CAN FIXED CELLS BE USED WITH THIS ASSAY?
    A. No. The ALDEFLUOR™ reagent is a substrate for the enzyme aldehyde dehydrogenase. ALDEFLUOR™ is a viability marker since the substrate is taken up, catalyzed and retained only by viable cells. It is important to ensure that reagents used for erythrocyte lysis do not contain a fixative.
  • Q. DOES THE ALDEFLUOR™ ASSAY WORK ON CRYOPRESERVED CELLS?
    A. ALDEFLUOR™ has been extensively tested on fresh and cryopreserved umbilical cord blood, peripheral blood and leukapheresis samples from patients and mobilized donors. If done correctly, cryopreservation and thawing should not cause loss in cell viability or fluorescence intensity of ALDHbr cells. As only viable cells retain the ALDEFLUOR™ reaction product, a loss in viability will be reflected as a decrease in the percentage of ALDHbr cells and an increase in the percentage of dead/dying cells (detectable by staining for propidium iodide or other viability dyes).
  
  DETECTING NON-HEMATOPOIETIC CELLS
  
  
  • Q. WILL ALDEFLUOR™ BUFFER PREVENT EFFLUX IN CELLS FROM NON-HEMATOPOIETIC TISSUES OR FROM OTHER SPECIES?
    A. The proprietary ALDEFLUOR™ assay buffer has been designed to optimize the detection of ALDH-positive (or ALDHbr) cells in human blood. The buffer contains an ATP-binding cassette (ABC) transport inhibitor that prevents active efflux of the ALDEFLUOR™ product from these cells. This transport inhibitor may not prevent efflux from other tissue types or from other species. Consequently, when using samples other than human blood, following the incubation with the activated ALDEFLUOR™ reagent at 37°C, the reacted cells should be kept at 2 - 8°C to prevent efflux, and thus the loss of fluorescence. For a list of additional efflux inhibitors that may be added to the ALDEFLUOR™ buffer see the "CAN I ADD ANY OTHER EFFLUX INHIBITORS TO THE ALDEFLUOR™ ASSAY BUFFER?" question.
  • Q. WILL DEAB INHIBIT ALDH ACTIVITY IN CELLS FROM NON-HEMATOPOIETIC TISSUES OR FROM OTHER SPECIES?
    A. The specific ALDH gene product expressed in non-human, non-blood products may not be inhibited by DEAB. A lack of difference between test and negative control samples may indicate that the inhibitor was not effective, or that there is no ALDH activity in the cells in the sample. Kinetic studies (a progressive increase in ALDEFLUOR™ fluorescence in the negative control tube with time of reaction) may be useful to differentiate these two alternatives. Other ALDH inhibitors can be used as appropriate for the enzyme isoform expressed. For example, Disulfuram inhibits several mammalian ALDH gene products.
  
  TISSUE-SPECIFIC PROTOCOL OPTIMIZATION
  
  
  • Q. CAN I USE A GREATER CONCENTRATION OF THE ALDEFLUOR™ SUBSTRATE TO IMPROVE THE DISCRIMINATION OF THE ALDHBR POPULATION?
    A. When staining non-blood products, it may be necessary to titrate the ALDEFLUOR™ substrate to determine the optimal concentration. We suggest a range of concentrations from 5-fold less to 10-fold more than the standard concentration. During titration we recommend maintaining the concentration of DEAB at 10-fold molar excess of activated ALDEFLUOR™ reagent, and therefore, it is necessary to adjust the amount of DEAB when titrating the substrate.
  
  ALDEFLUOR™-COMPATIBLE ASSAYS
  
  
  • Q. CAN I ANALYZE CELLS BY THE ALDEFLUOR™ ASSAY AND THE SIDE POPULATION ASSAY SIMULTANEOUSLY?
    A. Yes, the side population assay can be performed in conjunction with the ALDEFLUOR™ assay (Pearce and Bonnet. Exp Hematol 35: 1437-1446, 2007). The Side Population assay should be performed first, followed by the ALDEFLUOR™ assay. We recommend adding 50 µM verapamil to the ALDEFLUOR™ assay buffer when performing both assays.
  • Q. WHY ARE ALL THE CELLS IN THE CYTOGRAM FLUORESCENT TO SOME DEGREE?
    A. The ALDEFLUOR™ substrate is a non-polar fluorescent molecule that freely diffuses into all cells. In the DEAB-treated control, fluorescence will reflect the size of the intracellular substrate pool. Fluorescence in the test sample will additionally reflect ALDH activity. Human stem and progenitor cells typically have more ALDH activity than mature cells, and this quantitative difference allows stem cells to be resolved from the other cells.
  • Q. HOW DO I COMPENSATE FOR MULTIPARAMETER FLOW ANALYSIS WHEN THE STAINING OF ALDHBR CELLS IS SO BRIGHT?
    A. We would recommend washing your cells with ALDEFLUOR™ assay buffer after the reagent reaction to eliminate background fluorescence from excess substrate. The ALDEFLUOR™ reagent shows an emission spectrum similar to FITC with peak emission at 512 nm. Due to spectral overlap of the ALDEFLUOR™ reagent with fluorochromes that are detected below 650 nm, we recommend using antibodies conjugated to fluorochromes that emit at higher wavelengths for antigens which typically exhibit low levels of expression. For example, when studying the coexpression of CD34 on ALDHbr cells we used the antibody combination, CD45 phycoerythrin (PE), 7- aminoactinomycin D (7-AAD) and CD34 allophycocyanin (APC). Due to the brightness of the ALDEFLUOR™ reagent fluorophore, we strongly recommend the use of compensation controls for every experiment. Adequate compensation will not be achieved with commercially available fluorescent beads.

This product has been used in:

1. Ying Chen et al. Aldehyde dehydrogenase 1B1 (ALDH1B1) Is a Potential Biomarker for Human Colon Cancer.Biochem Biophys Res Commun (January 6, 2011)
2. M Yao et al. Prostate-regenerating capacity of cultured human adult prostate epithelial cells.Cells Tissues Organs 191 (3) 203-212 (2010)
3. Claus S Sondergaard et al. Human cord blood progenitors with high aldehyde dehydrogenase activity improve vascular density in a model of acute myocardial infarction.J Transl Med 8 24 (2010)
4. Junyang Lou et al. The effect of aspirin on endothelial progenitor cell biology: preliminary investigation of novel properties.Thromb Res 126 (3) e175-9 (September 2010)
5. Y Xiao et al. The lymphovascular embolus of inflammatory breast cancer exhibits a Notch 3 addiction.Oncogene (September 13, 2010)
6. Satoki Nakamura et al. The FOXM1 transcriptional factor promotes the proliferation of leukemia cells through modulation of cell cycle progression in acute myeloid leukemia.Carcinogenesis (September 10, 2010)
7. Congxiao Liu et al. Progenitor cell dose determines the pace and completeness of engraftment in a xenograft model for cord blood transplantation.Blood 116 (25) 5518-5527 (September 10, 2010)
8. Kota Ishizawa et al. Tumor-initiating cells are rare in many human tumors.Cell Stem Cell 7 (3) 279-282 (September 3, 2010)
9. Kanya Honoki et al. Possible involvement of stem-like populations with elevated ALDH1 in sarcomas for chemotherapeutic drug resistance.Oncol Rep 24 (2) 501-505 (August 2010)
10. Liheng Zhou et al. The prognostic role of cancer stem cells in breast cancer: a meta-analysis of published literatures.Breast Cancer Res Treat 122 (3) 795-801 (August 2010)
11. Jim B Boonyaratanakornkit et al. Selection of Tumorigenic Melanoma Cells Using ALDH.J Invest Dermatol (August 26, 2010)
12. Eren G??nd??z et al. Evaluation of mobilized peripheral stem cells according to CD34 and aldehyde dehydrogenase expression and effect of SSC(lo) ALDH(br) cells on hematopoietic recovery.Cytotherapy (August 24, 2010)
13. Michael Rasper et al. Aldehyde dehydrogenase 1 positive glioblastoma cells show brain tumor stem cell capacity.Neuro Oncol (July 13, 2010)
14. Matilde Todaro et al. Colon cancer stem cells: promise of targeted therapy.Gastroenterology 138 (6) 2151-2162 (June 2010)
15. Christel van den Hoogen et al. High aldehyde dehydrogenase activity identifies tumor-initiating and metastasis-initiating cells in human prostate cancer.Cancer Research 70 (12) 5163-5173 (June 15, 2010)
16. Franz-Josef Obermair et al. A novel classification of quiescent and transit amplifying adult neural stem cells by surface and metabolic markers permits a defined simultaneous isolation.Stem Cell Res (May 16, 2010)
17. Shuyang Sun et al. ALDH(high) adenoid cystic carcinoma cells display cancer stem cell properties and are responsible for mediating metastasis.Biochem Biophys Res Commun (May 4, 2010)
18. Shan Deng et al. Distinct Expression Levels and Patterns of Stem Cell Marker, Aldehyde Dehydrogenase Isoform 1 (ALDH1), in Human Epithelial CancersPLoS One 5 (4) (April 21, 2010)
19. Masumi Nagano et al. Hypoxia responsive mesenchymal stem cells derived from human umbilical cord blood are effective for bone repair.Stem Cells Dev (March 26, 2010)
20. Garrett G Muramoto et al. Inhibition of Aldehyde Dehydrogenase Expands Hematopoietic Stem Cells with Rradioprotective Capacity.Stem Cells (January 6, 2010)
21. Meritxell Rovira et al. Isolation and characterization of centroacinar/terminal ductal progenitor cells in adult mouse pancreas.Proc Natl Acad Sci U S A 107 (1) 75-80 (January 5, 2010)
22. Karine Vauchez et al. Aldehyde dehydrogenase activity identifies a population of human skeletal muscle cells with high myogenic capacities.Mol Ther 17 (11) 1948-1958 (November 2009)
23. Madhuri Kakarala et al. Targeting breast stem cells with the cancer preventive compounds curcumin and piperine.Breast Cancer Res Treat (November 7, 2009)
24. Thomas J Povsic et al. Aldehyde dehydrogenase activity allows reliable EPC enumeration in stored peripheral blood samples.J Thromb Thrombolysis 28 (3) 259-265 (October 2009)
25. Elise Jean et al. Aldehyde dehydrogenase activity promotes survival of human muscle precursor cells.J Cell Mol Med (October 16, 2009)
26. Joseph E Carpentino et al. Aldehyde dehydrogenase-expressing colon stem cells contribute to tumorigenesis in the transition from colitis to cancer.Cancer Res 69 (20) 8208-8215 (October 15, 2009)
27. Christophe Ginestier et al. Retinoid signaling regulates breast cancer stem cell differentiation.Cell Cycle 8 (20) 3297-3302 (October 15, 2009)
28. Dan Ran et al. Aldehyde dehydrogenase activity among primary leukemia cells is associated with stem cell features and correlates with adverse clinical outcomes.Exp Hematol 37 (12) 1423-1434 (October 8, 2009)
29. Olivier Pierre-Louis et al. Dual SP/ALDH Functionalities Refine The Human Hematopoietic Lin(-) CD34(+) CD38(-) Stem/Progenitor Cell Compartment.Stem Cells 27 (10) 2552-2562 (July 30, 2009)
30. Benjamin J Capoccia et al. Revascularization of ischemic limbs after transplantation of human bone marrow cells with high aldehyde dehydrogenase activity.Blood 113 (21) 5340-5351 (May 21, 2009)
31. Feng Jiang et al. Aldehyde dehydrogenase 1 is a tumor stem cell-associated marker in lung cancer.Mol Cancer Res 7 (3) 330-338 (March 2009)
32. Thomas J Povsic et al. Common endothelial progenitor cell assays identify discrete endothelial progenitor cell populations.Am Heart J 157 (2) 335-344 (February 2009)
33. Antonio Jimeno et al. A direct pancreatic cancer xenograft model as a platform for cancer stem cell therapeutic development.Mol Cancer Ther 8 (2) 310-314 (February 2009)
34. Scott J Dylla et al. Colorectal cancer stem cells are enriched in xenogeneic tumors following chemotherapy.PLoS One 3 (6) e2428 (2008)
35. S A Boxall et al. Haematopoietic repopulating activity in human cord blood CD133(+) quiescent cells.Bone Marrow Transplant 43 (8) 627-635 (November 10, 2008)
36. Stefania Corti et al. Neural stem cell transplantation can ameliorate the phenotype of a mouse model of spinal muscular atrophy.J Clin Invest 118 (10) 3316-3330 (October 2008)
37. Georg Feldmann et al. An orally bioavailable small-molecule inhibitor of Hedgehog signaling inhibits tumor initiation and metastasis in pancreatic cancer.Mol Cancer Ther 7 (9) 2725-2735 (September 2008)
38. M Lioznov et al. Transportation and cryopreservation may impair haematopoietic stem cell function and engraftment of allogeneic PBSCs, but not BM.Bone Marrow Transplant 42 (2) 121-128 (July 2008)
39. Peppino Mirabelli et al. Extended flow cytometry characterization of normal bone marrow progenitor cells by simultaneous detection of aldehyde dehydrogenase and early hematopoietic antigens: implication for erythroid differentiation studies.BMC Physiology 8 (1) 13 (May 29, 2008)
40. Suling Liu et al. BRCA1 regulates human mammary stem/progenitor cell fate.Proc Natl Acad Sci U S A 105 (5) 1680-1685 (January 29, 2008)
41. William Matsui et al. Clonogenic multiple myeloma progenitors, stem cell properties, and drug resistance.Cancer Res 68 (1) 190-197 (January 1, 2008)
42. T Gentry et al. Isolation of early hematopoietic cells, including megakaryocyte progenitors, in the ALDH-bright cell population of cryopreserved, banked UC blood.Cytotherapy 9 (6) 569-576 (2007)
43. T Gentry et al. Simultaneous isolation of human BM hematopoietic, endothelial and mesenchymal progenitor cells by flow sorting based on aldehyde dehydrogenase activity: implications for cell therapy.Cytotherapy 9 (3) 259-274 (2007)
44. Ingrid Ibarra et al. A role for microRNAs in maintenance of mouse mammary epithelial progenitor cells.Genes Dev. 21 (24) 3238-3243 (December 15, 2007)
45. Roberta Riccioni et al. M4 and M5 acute myeloid leukaemias display a high sensitivity to Bortezomib-mediated apoptosis.Br J Haematol 139 (2) 194-205 (October 2007)
46. Daniel J Pearce et al. The combined use of Hoechst efflux ability and aldehyde dehydrogenase activity to identify murine and human hematopoietic stem cells.Exp Hematol 35 (9) 1437-1446 (September 2007)
47. Jan S Moreb et al. Heterogeneity of aldehyde dehydrogenase expression in lung cancer cell lines is revealed by Aldefluor flow cytometry-based assay.Cytometry B Clin Cytom 72 (4) 281-289 (July 2007)
48. A M S Cheung et al. Aldehyde dehydrogenase activity in leukemic blasts defines a subgroup of acute myeloid leukemia with adverse prognosis and superior NOD/SCID engrafting potential.Leukemia 21 (7) 1423-1430 (July 2007)
49. Eli E. Bar et al. Cyclopamine-mediated hedgehog pathway inhibition depletes stem-like cancer cells in glioblastoma.Stem Cells 25 (10) 2007-0166 (July 12, 2007)
50. Piero Dalerba et al. Phenotypic characterization of human colorectal cancer stem cells.Proc Natl Acad Sci U S A 104 (24) 10158-10163 (June 12, 2007)
51. Georg Feldmann et al. Blockade of hedgehog signaling inhibits pancreatic cancer invasion and metastases: a new paradigm for combination therapy in solid cancers.Cancer Res 67 (5) 2187-2196 (March 1, 2007)
52. Tarja A Juopperi et al. Isolation of bone marrow-derived stem cells using density-gradient separation.Exp Hematol 35 (2) 335-341 (February 2007)
53. John P Chute et al. Inhibition of aldehyde dehydrogenase and retinoid signaling induces the expansion of human hematopoietic stem cells.Proc Natl Acad Sci U S A 103 (31) 11707-11712 (August 1, 2006)
54. Stefania Corti et al. Identification of a primitive brain-derived neural stem cell population based on aldehyde dehydrogenase activity.Stem Cells 24 (4) 975-985 (April 2006)
55. David Hess et al. Selection based on CD133 and high aldehyde dehydrogenase activity isolates long-term reconstituting human hematopoietic stem cells.Blood 107 (5) 2162-2169 (March 1, 2006)
56. Stefania Corti et al. Transplanted ALDHhiSSClo neural stem cells generate motor neurons and delay disease progression of nmd mice, an animal model of SMARD1.Hum Mol Genet 15 (2) 167-187 (January 15, 2006)
57. Diana J Laird et al. Stem cells are units of natural selection in a colonial ascidian.Cell 123 (7) 1351-1360 (December 29, 2005)
58. Robert W Storms et al. Distinct hematopoietic progenitor compartments are delineated by the expression of aldehyde dehydrogenase and CD34.Blood 106 (1) 95-102 (July 1, 2005)
59. M V Lioznov et al. Aldehyde dehydrogenase activity as a marker for the quality of hematopoietic stem cell transplants.Bone Marrow Transplant 35 (9) 909-914 (May 2005)
60. Lyle Armstrong et al. Phenotypic characterization of murine primitive hematopoietic progenitor cells isolated on basis of aldehyde dehydrogenase activity.Stem Cells 22 (7) 1142-1151 (2004)
61. Jingli Cai et al. In search of "stemness".Exp Hematol 32 (7) 585-598 (July 2004)
62. Jingli Cai et al. Membrane properties of rat embryonic multipotent neural stem cells.J Neurochem 88 (1) 212-226 (January 2004)
63. Paul Fallon et al. Mobilized peripheral blood SSCloALDHbr cells have the phenotypic and functional properties of primitive haematopoietic cells and their number correlates with engraftment following autologous transplantation.Br J Haematol 122 (1) 99-108 (July 2003)
64. R W Storms et al. Isolation of primitive human hematopoietic progenitors on the basis of aldehyde dehydrogenase activity.Proc Natl Acad Sci U S A 96 (16) 9118-9123 (August 3, 1999)
65. R J Jones et al. Characterization of mouse lymphohematopoietic stem cells lacking spleen colony-forming activity.Blood 88 (2) 487-491 (July 15, 1996)
66. R J Jones et al. Assessment of aldehyde dehydrogenase in viable cells.Blood 85 (10) 2742-2746 (May 15, 1995)
67. Daniel J Pearce et al. Characterization of cells with a high aldehyde dehydrogenase activity from cord blood and acute myeloid leukemia samples.Stem Cells 23 (6) 752-760