title: Silica wool filtration (SIFT) assay: a simple system to estimate the percentage of acrosome-reacted sperm.
abstract: OBJECTIVE
  To develop a simple assay using the silica wool filtration (SIFT) procedure to estimate percentage of acrosome-reacted (AR) sperm.
  
  
  METHODS
  Private andrology laboratory.
  
  
  METHODS
  Capacitated sperm processed by the SIFT procedure to remove nonviable sperm and those with broken membrane were acrosome reacted by induction with a calcium ionophore. Following the acrosome reaction, the sample was processed by the SIFT procedure. Sperm concentration and acrosomal status were also determined before and after the SIFT procedure.
  
  
  RESULTS
  The SIFT procedure prevented AR sperm from filtering (mean +/- SD, 22.2 +/- 1.9 vs. 9.8 +/- 4.9%). The mean percent of sperm retained in the filter (SIFT assay: 61.8 +/- 21.5%) was significantly higher than the percent of AR sperm estimated by a staining technique (26.4 +/- 7.3%), but they were significantly correlated (r = .34) with each other. The filtration of capacitated sperm prior to induction of the acrosome reaction eliminated, or at least minimized, the possibility of falsely increasing the percent of AR sperm estimated by the SIFT assay. The higher estimate obtained by SIFT assay, therefore, suggests that it may be estimating sperm at various stages that are undergoing the acrosome reaction.
  
  
  CONCLUSIONS
  The findings suggest that the SIFT assay could be used to estimate the percentage of AR spermatozoa.
authors.affiliation: Northwestern University Medical School, Chicago, Illinois, USA.
authors.forename: J
authors.initials: J
authors.lastname: Fan
authors.forename: V C
authors.initials: VC
authors.lastname: Acosta
authors.forename: K
authors.initials: K
authors.lastname: Yao
authors.forename: N
authors.initials: N
authors.lastname: Jeyadevan
authors.forename: R S
authors.initials: RS
authors.lastname: Jeyendran
mesh_terms: D000177:Acrosome / Q000378:metabolism*; D005307:Fertilization in Vitro / Q000379:methods*; D005374:Filtration / Q000379:methods; D006801:Humans; D008297:Male; D012016:Reference Values; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide; D013075:Sperm Capacitation / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D012822:Silicon Dioxide