BurnhamInstitute SanDiego CA92037 USA;
DepartmentofGynecologyandObstetrics ChanghaiHospital;
DepartmentofHistologyandEmbryology PekingUniversity Peking P.R.China;
DepartmentofMicrobiology;
SecondMilitaryMedicalUniversity Shanghai 200433 P.R.China;
Nationalstemcellcenter PekingUniversity Peking P.R.China;