Methods:1) The CD34~+ hematopoietic stem cells were isolated from mononuclear cells prepared with Ficoll-Hypaque density-gradients centrifugation from human cord blood using CD34~+Progenitor Cell Isolation Kit by magnetic cell sorting system (MACS);

• 方法:1)利用Ficoll-Hypaque密度梯度离心法分离脐静脉血单个核细胞,免疫磁珠法分离脐血CD34~+干细胞。