title: Quantification of nucleolar channel systems: uniform presence throughout the upper endometrial cavity.
abstract: OBJECTIVE
  To determine the prevalence of nucleolar channel systems (NCSs) by uterine region, applying continuous quantification.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Tertiary care academic medical center.
  
  
  METHODS
  Forty-two naturally cycling women who underwent hysterectomy for benign indications.
  
  
  METHODS
  NCS presence was quantified by a novel method in six uterine regions-fundus, left cornu, right cornu, anterior body, posterior body, and lower uterine segment (LUS)-with the use of indirect immunofluorescence.
  
  
  METHODS
  Percentage of endometrial epithelial cells (EECs) with NCSs per uterine region.
  
  
  RESULTS
  NCS quantification was observer independent (intraclass correlation coefficient 0.96) and its intrasample variability low (coefficient of variation 0.06). Eleven of 42 hysterectomy specimens were midluteal, ten of which were analyzable with nine containing >5% EECs with NCSs in at least one region. The percentage of EECs with NCSs varied significantly between the LUS (6.1%; interquartile range [IQR] 3.0-9.9) and the upper five regions (16.9%; IQR 12.7-23.4), with fewer NCSs in the basal layer of the endometrium (17 ± 6%) versus the middle (46 ± 9%) and luminal layers (38 ± 9%) of all six regions.
  
  
  CONCLUSIONS
  NCS quantification during the midluteal phase demonstrates uniform presence throughout the endometrial cavity, excluding the LUS, with a preference for the functional luminal layers. Our quantitative NCS evaluation provides a benchmark for future studies and further supports NCS presence as a potential marker for the window of implantation.
authors.affiliation: Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Szmyga
authors.forename: Eli A
authors.initials: EA
authors.lastname: Rybak
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Nejat
authors.forename: Erika H
authors.initials: EH
authors.lastname: Banks
authors.forename: Kathleen D
authors.initials: KD
authors.lastname: Whitney
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Polotsky
authors.forename: Debra S
authors.initials: DS
authors.lastname: Heller
authors.forename: U Thomas
authors.initials: UT
authors.lastname: Meier
mesh_terms: D000328:Adult; D001706:Biopsy; D002466:Cell Nucleolus / Q000648:ultrastructure*; D004717:Endometrium / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation