[The probability of microbiological contamination during the collection and processing of umbilical cord blood].

To study the pathogens incidences in cord blood and the efficiency of different detective methods, 60 samples were drawn and reserved from collected and processed cord blood, respectively. The BACTEC 9050 system, improved Martin/thioglycollate broth (22 degrees C) and thioglycollate broth (35 degrees C) were employed to detected bacteria (including fungus) at the same time. Two hundred and six cord blood serum samples were used to detect the HBV DNA and HCV RNA by molecular biology technique, HBsAg, Anti-HBC, Anti-HCV, Anti-HCMV-IgM, HTLV-1, HTLV-2, HIV-1 and HIV-2 by ELISA and RBC agglutination test were used to detect the TPHA.

[Effects of cryopreservation length on the proliferative potential of cord blood hematopoietic cells in vitro].

Aim: To study the effects of cryopreservation length on the proliferative potential of hematopoietic cells derived from cord blood.

Methods: Using Dextran-40 and 10% DMSO as cryoprotectants, separated nuclear cells were stored in liquid nitrogen after they were freezed according programme. One month or 4 months later, they were thawed and expanded in serum-free medium for culture and expansion of hematopoietic cell (SFEM) for 5 weeks.