Embryonic stem cells have remarkable proliferative and differentiation developmental capabilities and thus have great potential for cell therapy, disease modeling, and drug development. However, such totipotency has resulted in genomic instability, especially in the case of DNA damage. Human embryonic stem cells possess particular repair mechanisms to avoid the accumulation of such damage within the cell or its transmission to the offspring, thus ensuring the accuracy and safety of self-replication and differentiation development. This paper summarized the repair mechanisms of DNA damage in human embryonic stem cells and intends to provide a basis for further exploration of new ideas of stem cell therapy in conjunction with their repair mechanisms.

Embryonic stem cells have remarkable proliferative and differentiation developmental capabilities and thus have great potential for cell therapy, disease modeling, and drug development. However, such totipotency has resulted in genomic instability, especially in the case of DNA damage. Human embryonic stem cells possess particular repair mechanisms to avoid the accumulation of such damage within the cell or its transmission to the offspring, thus ensuring the accuracy and safety of self-replication and differentiation development. This paper summarized the repair mechanisms of DNA damage in human embryonic stem cells and intends to provide a basis for further exploration of new ideas of stem cell therapy in conjunction with their repair mechanisms.

Objective To constitute a database of chronic wounds for characterizing the patients with chronic wounds.Methods Based on the guideline of chronic wounds defined by international wound healing society,86 outpatients with chronic wounds were selected between January and October in 2013 to set up a wound database using the wound information management system.The parameters including etiology,age distribution,mean time of fracture healing and wound healing time posterior to different treatments were analyzed.Results (1) Statistical difference existed for cause distribution (P ＜0.05).Top three causes were trauma (29％),varicosity (26％) and pressure sore (19％).(2) Age distribution varied significantly among the patients with various causes of chronic wounds (P ＜ 0.05).(3) Statistical difference was observed in healing time of various types of chronic wounds (P ＜ 0.05).Diabetic wound and varicose ulcer took the longest healing time,with average 116.36 days and 88.48 days respectively.(4) Patients treated with novel dressings had shorter healing time than those managed with traditional dressings (P ＜ 0.05).Conclusions Trauma,varicosity and pressure ulcer are relatively common among the outpatients.Etiology of chronic wounds is strongly related to age and novel dressings contributed to a shortened cause of the disorder.