NCJ Number
248155
Journal
Forensic Science International Genetics Volume: 12 Dated: September 2014 Pages: 161-167
Date Published
September 2014
Length
7 pages
Annotation
Results for the identification of spermatozoa from sexual assault evidence were compared with the use of a fluorescent microscopy method (SPERM HY-LITER) and Baecchi's method for the identification of human spermatozoa (traditional histological staining).
Abstract
The study found that SPERM HY-LITER was generally more effective than traditional histological staining by Baicchi's method. SPERM HY-LTER was also specific for human spermatozoa; whereas, Baecchi's method did not distinguish between human and non-human sperm contributors. The higher specificity and effectiveness of SPERM HY-LITER thus enables faster and more reliable visual screening of evidentiary material for spermatozoa. SPERM HY-LITER was developed and validated for the microscopic analysis of human spermatozoa from sexual assault evidence. The specificity of this method is obtained through an Alexa 488 fluorescently (green flourescein isothiocyanate - FTIC) tagged monoclonal antibody, which specifically targets an antigen on the nuclear membrane of sperm cells. In conjunction with the Alexa 488 tag, the blue nuclear stain, 4',6-diamidino-2-pheny-lindole (DAPI) is also incorporated as part of the staining. As a result, all cells containing DNA-rich nuclei can be visualized through the selective use of a DAPI compatible fluorescent filter. This enables the visualization of the various cells without the need for selective degradation of epithelial vaginal cells by proteinase K treatment prior to microscopic analysis. Due to the intense fluorescence, as few as one sperm cell can be identified among a dense sample of vaginal epithelial cells common in sexual assault type swabs. 5 tables, 2 figures, and 22 references