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Phuong Doan

Hematopoietic stem cells (HSCs) are enriched for aldehyde dehydrogenase (ALDH) activity and ALDH is a selectable marker for human HSCs. However, the function of ALDH in HSC biology is not well understood. We sought to determine the... more
Hematopoietic stem cells (HSCs) are enriched for aldehyde dehydrogenase (ALDH) activity and ALDH is a selectable marker for human HSCs. However, the function of ALDH in HSC biology is not well understood. We sought to determine the function of ALDH in regulating HSC fate. Pharmacologic inhibition of ALDH with diethylaminobenzaldehyde (DEAB) impeded the differentiation of murine CD34−c-kit+Sca-1+lineage− (34−KSL) HSCs in culture and facilitated a ninefold expansion of cells capable of radioprotecting lethally irradiated mice compared to input 34−KSL cells. Treatment of bone marrow (BM) 34−KSL cells with DEAB caused a fourfold increase in 4-week competitive repopulating units, verifying the amplification of short-term HSCs (ST-HSCs) in response to ALDH inhibition. Targeted siRNA of ALDH1a1 in BM HSCs caused a comparable expansion of radioprotective progenitor cells in culture compared to DEAB treatment, confirming that ALDH1a1 was the target of DEAB inhibition. The addition of all trans retinoic acid blocked DEAB-mediated expansion of ST-HSCs in culture, suggesting that ALDH1a1 regulates HSC differentiation via augmentation of retinoid signaling. Pharmacologic inhibition of ALDH has therapeutic potential as a means to amplify ST-HSCs for transplantation purposes. STEM CELLS 2010;28:523–534
Umbilical cord blood transplantation is becoming an acceptable alternative source of hematopoietic stem cells for patients with malignant diseases. Cord blood differs from bone marrow and peripheral blood progenitors in its immune... more
Umbilical cord blood transplantation is becoming an acceptable alternative source of hematopoietic stem cells for patients with malignant diseases. Cord blood differs from bone marrow and peripheral blood progenitors in its immune tolerance and kinetics of engraftment. In this article, we will review the biology of cord blood stem cells and clinical studies of cord blood transplants in pediatric and adult populations. We will also discuss potential uses of cord blood stem cells in regenerative medicine and novel methods for ex vivo expansion of hematopoietic stem cells. As we learn more about cord blood transplants, there is the potential to overcome the limitations of cord blood transplants so that they can become more widely available.
Research Interests:
The management of the interim phase of a complete oral rehabilitation in patients with severely worn dentition is often challenging due to loss of occlusal vertical dimension, loss of tooth structure, uneven wear of teeth creating an... more
The management of the interim phase of a complete oral rehabilitation in patients with severely worn dentition is often challenging due to loss of occlusal vertical dimension, loss of tooth structure, uneven wear of teeth creating an uneven plane of occlusion, and para-functional habits. This paper will demonstrate how a clear thermo-forming matrix fabricated from the diagnostic wax-up can be used as a guide to facilitate treatment.
Research Interests: