The candidate, Oozawa Kuniaki (from Gunma Prefecture), received a Doctor of Medicine degree from Tokyo University of Science. His dissertation, titled "Long-Term Lymphohematopoietic Reconstitution by a Single CD34-Low/Negative Hematopoietic Stem Cell," investigates the identification and characterization of hematopoietic stem cells (HSCs). The study focuses on CD34-negative/Lin-negative/Sca-1-positive/c-Kit-positive cells, which are considered to be the most undifferentiated HSCs. Using FACS and other techniques, the candidate purified and analyzed these cells, demonstrating their ability to reconstitute hematopoiesis in mice over a long period. The results showed that CD34-negative/Lin-negative/Sca-1-positive/c-Kit-positive cells have a high frequency of hematopoietic stem cells, with over 80% of cells forming mixed colonies. Additionally, single-cell transplantation of these cells resulted in long-term hematopoietic reconstitution, indicating their high potency. The study also highlights the importance of understanding HSCs for clinical applications, as HSC dysfunction can lead to various hematological disorders. The candidate's research provides new insights into the identification and purification of HSCs, and the findings suggest that CD34-negative/Lin-negative/Sca-1-positive/c-Kit-positive cells may be a more accurate marker for HSCs in humans. The dissertation was evaluated by several professors from Tokyo University of Science, and the candidate was found to have sufficient qualifications to receive the Doctor of Medicine degree.The candidate, Oozawa Kuniaki (from Gunma Prefecture), received a Doctor of Medicine degree from Tokyo University of Science. His dissertation, titled "Long-Term Lymphohematopoietic Reconstitution by a Single CD34-Low/Negative Hematopoietic Stem Cell," investigates the identification and characterization of hematopoietic stem cells (HSCs). The study focuses on CD34-negative/Lin-negative/Sca-1-positive/c-Kit-positive cells, which are considered to be the most undifferentiated HSCs. Using FACS and other techniques, the candidate purified and analyzed these cells, demonstrating their ability to reconstitute hematopoiesis in mice over a long period. The results showed that CD34-negative/Lin-negative/Sca-1-positive/c-Kit-positive cells have a high frequency of hematopoietic stem cells, with over 80% of cells forming mixed colonies. Additionally, single-cell transplantation of these cells resulted in long-term hematopoietic reconstitution, indicating their high potency. The study also highlights the importance of understanding HSCs for clinical applications, as HSC dysfunction can lead to various hematological disorders. The candidate's research provides new insights into the identification and purification of HSCs, and the findings suggest that CD34-negative/Lin-negative/Sca-1-positive/c-Kit-positive cells may be a more accurate marker for HSCs in humans. The dissertation was evaluated by several professors from Tokyo University of Science, and the candidate was found to have sufficient qualifications to receive the Doctor of Medicine degree.