RESUMO
OBJECTIVE: To study the impact of anticoagulant to the quality of umbilical cord blood (UCB). METHODS: 6060 cord blood units (CBUs) were classified into five groups, such as 28 ml: (10-29) ml, 28 ml: (30-69) ml, 28 ml: (70-109) ml, 28 ml: (110-150) ml and 28 ml: (>150) ml according to volume ratio of anticoagulant and CBVs. The count of pre-cryopreservation total nucleated cell (pre-TNC), the viability of nucleated cell (VNC), the amount of CFU-GM and the ratio changes of CD34+ were evaluated and analyzed statistically. RESULTS: It was found that pre-TNC increased with the growth of volume of CBUs (r=0.9937) under the certain volume of antico-agulant, and the TNC in the minimum UCB volume group was (2.57±0.89)×108; the VNC grew up with the increasing count viability of volume (r=0.9897), and the average viability of the minimum volume group remained over 95%; the CFU-GM climbed up with the increasing of volume (r=0.9024), and the number of CFV-GM in minimum volume group reached to of 89/×105; CD34+% grew up with the increase of volume of CBUs (r=0.9641), and the ratio was (0.30±0.19)% for the minimum volume group. CONCLUSION: In certain volume of anticoagulant in collection-bag, pre-TNC, VNC, CFU-GM and CD34+% are all dropped with the decrease of CBUs volume , however, all above-mentioned indexes in the minimun random group still meet the requirement for clinical administration.
Assuntos
Criopreservação , Sangue Fetal , HumanosRESUMO
High-throughput screening, a powerful tool for the discovery of functionally important genes responsible for certain phenotypes, is performed according to loss-of-function or gain-of-function strategies. RNAi technology or knockout approaches have been widely used in high throughput screening due to their advantages of ease use, low cost and so on. However, imcomplete knockdown activity and off-target effect hindered their utility. More recently, CRISPR/Cas9 technology is becoming a robust tool for genome editing in diverse cells or animals, since it could generate a gene mutation in a target-specific manner. In this review, we first summarize the characterization of CRISPR/Cas9 and make comparison with traditional genetic tools, then describe recent achievements of genetic screen in several model organisms using CRISPR/Cas9, finally discuss on its future challenges and opportunities.
