title: Efficiency of slush nitrogen vitrification of human oocytes vitrified with or without cumulus cells in relation to survival rate and meiotic spindle competence.
abstract: OBJECTIVE
  To evaluate the efficiency of slush nitrogen vitrification of human oocytes with or without cumulus cells in terms of survival rate and maintenance of meiotic spindle.
  
  
  METHODS
  Randomized, comparative study.
  
  
  METHODS
  Medical center.
  
  
  METHODS
  A total of 274 oocytes obtained from 46 couples undergoing infertility treatment.
  
  
  METHODS
  Metaphase II oocytes were divided into groups A and B, vitrified with and without cumulus cells, respectively.
  
  
  METHODS
  Survival rates and maintenance of meiotic spindle observed immediately after warming and 3 hours after incubation.
  
  
  RESULTS
  No statistically significant difference was detected between the two groups in terms of survival rate, but a significantly higher percentage of detectable spindle was observed in group B (completely denuded oocytes), either immediately after warming or 3 hours after incubation.
  
  
  CONCLUSIONS
  Complete denudation of oocytes before slush nitrogen vitrification does not influence survival rates but positively affects oocyte meiotic spindle competence. These data support the hypothesis that cumulus cells during vitrification represent an obstacle to cryoprotectant penetration more than having a protective role for the oocyte.
authors.affiliation: Center for Reproductive Medicine, European Hospital, Rome, Italy. mg.minasi@gmail.com
authors.forename: Maria Giulia
authors.initials: MG
authors.lastname: Minasi
authors.forename: Gemma
authors.initials: G
authors.lastname: Fabozzi
authors.forename: Valentina
authors.initials: V
authors.lastname: Casciani
authors.forename: Susanna
authors.initials: S
authors.lastname: Ferrero
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Litwicka
authors.forename: Ermanno
authors.initials: E
authors.lastname: Greco
mesh_terms: D000328:Adult; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods*; D054885:Cumulus Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D007246:Infertility / Q000503:physiopathology / Q000628:therapy*; D007558:Italy; D008540:Meiosis; D008854:Microscopy, Electron; D009584:Nitrogen; D009865:Oocytes / Q000473:pathology*; D011247:Pregnancy; D027724:Reproductive Techniques, Assisted; D008941:Spindle Apparatus / Q000473:pathology*; D013997:Time Factors; D058989:Vitrification
chemical_list: D009584:Nitrogen