title: Timing the window of implantation by nucleolar channel system prevalence matches the accuracy of the endometrial receptivity array.
abstract: OBJECTIVE
  To test if nucleolar channel system (NCS) prevalence matches the accuracy of the endometrial receptivity array (ERA) for identification of the window of endometrial receptivity.
  
  
  METHODS
  Comparative retrospective study, May 2008-May 2012.
  
  
  METHODS
  University-affiliated infertility clinic.
  
  
  METHODS
  Forty-nine healthy oocyte donors, regularly cycling, aged 20-34 years with a body mass index of 19-25 kg/m2.
  
  
  METHODS
  Endometrial biopsies were collected throughout the menstrual cycle. All samples underwent transcriptomic signature identification by ERA testing (performed in a prior study) and quantification of NCS prevalence by using indirect immunofluorescence (performed in the present study).
  
  
  METHODS
  Concordance of ERA results determining the window of implantation with NCS prevalence was statistically analyzed using the kappa index. Based on dating according to the luteinizing hormone surge, specimens were dichotomized into receptive (n=24) and nonreceptive (n=25). The NCS prevalence was expressed as percentage of NCSs per endometrial epithelial cells in each endometrial biopsy.
  
  
  RESULTS
  Concordance of ERA and NCS dating vs. luteinizing hormone yielded comparable kappa indices of 0.878 and 0.836, respectively. Direct comparison of ERA and NCS dating resulted in a kappa index of 0.796.
  
  
  CONCLUSIONS
  Prevalence of NCS identifies the window of endometrial receptivity previously identified by their transcriptomic signature using the ERA.
authors.affiliation: Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York; Department of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Nejat
authors.affiliation: IVIOMICS, Paterna, Valencia, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Ruiz-Alonso
authors.affiliation: IVIOMICS, Paterna, Valencia, Spain; Fundación Instituto Valenciano de Infertilidad, Valencia University, Valencia, Spain; Instituto Universitario IVI/Incliva, Valencia University, Valencia, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Simón
authors.affiliation: Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York. Electronic address: tom.meier@einstein.yu.edu.
authors.forename: U Thomas
authors.initials: UT
authors.lastname: Meier
mesh_terms: D000328:Adult; D002466:Cell Nucleolus / Q000378:metabolism*; D010064:Embryo Implantation; D004717:Endometrium / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D006801:Humans; D008183:Luteal Phase / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D018587:Oocyte Donation; D010061:Ovulation Detection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059467:Transcriptome / Q000502:physiology*; D055815:Young Adult
chemical_list: D009687:Nuclear Proteins
keywords: Nucleolar channel system (NCS); endometrial receptivity array (ERA); endometrium; receptivity; window of implantation (WOI)