title: Fertilization failure from a sperm chromatin defect in couples with unexplained infertility.
abstract: OBJECTIVE
  To investigate the relationship between unexplained infertility and fertilization failure from nucleoprotein defects in ejaculated human sperm and to study the usefulness of sperm chromatin assays, using AO fluorescence dye, to evaluate patients with unexplained infertility before treatment.
  
  
  METHODS
  From January 1999 to January 2000, 513 infertile couples had the clinical causes of their infertility assessed. During the next investigative period (February 2000-February 2001), 137 cases of unexplained infertility (n = 80) were chosen for this study, as were cases of tubal factor infertility (n = 57) as controls. The status of nuclear chromatin in ejaculated sperm was examined using acridine orange staining, followed by a conventional in vitro fertilization procedure.
  
  
  RESULTS
  The number of patients with immature ejaculated sperm was 16 of 30 (53.3%) unexplained infertility cases involving fertilization failure, 8 of 50 (16.0%) unexplained infertility cases without fertilization failure and 5 of 57 (8.8%) tubal factor infertility cases. A significant difference was observed between unexplained infertility cases with fertilization failure and the other groups (P < .0001).
  
  
  CONCLUSIONS
  These results suggest that the nuclear immaturity of ejaculated human sperm may be 1 of the primary factors underlying unexplained infertility.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Fukushima Medical University, 1-Hikarigaoka, Fukushima, Japan. katayose@fmu.ac.jp
authors.forename: Haruo
authors.initials: H
authors.lastname: Katayose
authors.forename: Kaoru
authors.initials: K
authors.lastname: Yanagida
authors.forename: Shoutaro
authors.initials: S
authors.lastname: Hayashi
authors.forename: Shouji
authors.initials: S
authors.lastname: Kuretake
authors.forename: Kazuto
authors.initials: K
authors.lastname: Morozumi
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
mesh_terms: D000165:Acridine Orange; D000328:Adult; D002843:Chromatin / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007248:Infertility, Male / Q000473:pathology*; D008297:Male; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000002:abnormalities* / Q000000981:diagnostic imaging; D017211:Treatment Failure; D014463:Ultrasonography
chemical_list: D002843:Chromatin; D005456:Fluorescent Dyes; D000165:Acridine Orange