title: Toluidine blue test for sperm DNA integrity and elaboration of image cytometry algorithm.
abstract: BACKGROUND
  Sperm DNA integrity is of paramount importance in the prognosis of fertility. We applied image cytometry to a toluidine blue (TB) test we recently proposed.
  
  
  METHODS
  Sperm samples from 33 men were assayed for standard sperm parameters and classified as normal or abnormal. Sperm smears were subjected to the TB test, DNA denaturation testing with acridine orange (AO), and terminal deoxyuridine triphosphate biotin nick end labeling (TUNEL). In CCD image analysis, TB-stained sperm cell heads were microscopically assigned to one of four color groups (dark, blue, light violet, and light blue). The optical densities of 6,600 cells in green and red CCD images were used to elaborate an algorithm for discrimination of these groups.
  
  
  RESULTS
  The proportions of sperm in TB color groups, as estimated with the developed image cytometry algorithm, correlated with microscopic features. The number of TB dark cells correlated with the number of AO-red and TUNEL(+) cells. The proportion of TB dark cells in normal samples did not exceed 35%. Light-blue sperm cell heads prevailed in normal samples, whereas dark and blue sperm cell heads dominated in abnormal samples.
  
  
  CONCLUSIONS
  The TB test was suitable for the assessment of sperm cell DNA integrity. The elaborated image cytometry algorithm can be used for this purpose and for finer determination of sperm nucleus status.
authors.affiliation: Biomedical Research and Study Centre, University of Latvia, Riga, Latvia. katrina@biomed.lu.lv
authors.forename: Jekaterina
authors.initials: J
authors.lastname: Erenpreisa
authors.forename: Juris
authors.initials: J
authors.lastname: Erenpreiss
authors.forename: Talivaldis
authors.initials: T
authors.lastname: Freivalds
authors.forename: Maija
authors.initials: M
authors.lastname: Slaidina
authors.forename: Rasma
authors.initials: R
authors.lastname: Krampe
authors.forename: Jelena
authors.initials: J
authors.lastname: Butikova
authors.forename: Andrey
authors.initials: A
authors.lastname: Ivanov
authors.forename: Dace
authors.initials: D
authors.lastname: Pjanova
mesh_terms: D000165:Acridine Orange / Q000494:pharmacology; D000465:Algorithms; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000737:chemistry; D006801:Humans; D019044:Image Cytometry / Q000379:methods*; D020287:In Situ Nick-End Labeling; D008297:Male; D008853:Microscopy / Q000379:methods*; D018715:Microscopy, Video; D013094:Spermatozoa / Q000378:metabolism*; D014048:Tolonium Chloride / Q000494:pharmacology*
chemical_list: D002843:Chromatin; D014048:Tolonium Chloride; D004247:DNA; D003851:Deoxyribonucleases; D000165:Acridine Orange