Sperm Cell Capture Based on ABH Antigen Differences to Separate Two Men in Mixed Seminal Stains

Personal identification of two individuals in mixed semen samples in forensic DNA testing in general usually involves analysis using autosomal and Y chromosome short tandem repeats (STRs). Results may exclude unrelated donors but cannot identify individuals. In this study, sperm cell capture based on ABH antigen differences was used to obtain the cells with the single ABO blood type. Immunohistochemical staining using labeled anti-A, anti-B, and anti-H antibodies and the laser microdissection system can be used to enrich sperm with different ABO types in mixed seminal stains from two individuals. Then, PCR amplification and capillary electrophoresis were performed to genotype the STR loci. To some extent, after sperm cell capture based on ABH antigen differences, autosomal STR typing using enriched single blood group cells can be utilized to partially identify different individuals in a mixed seminal stain sample from two individuals.

Thermal Effects on DNA Degradation in Blood and Seminal Stains: Forensic View

Forensic investigations using DNA analysis have been grown rapidly. Samples retrieved from crime scene may be exposed to different conditions before proceeding. This study aimed to evaluate the effect of different grades of temperature and burn on DNA extraction and typing. Methods: Seven mL of blood and four mL of semen were collected from each volunteer. Effects of temperature grades (100 °C, 50 °C, 37 °C, 4 °C, −20 °C, and burn) on blood and seminal stain were tested. Results: Bloodstains exposed to temperature grades 100 °C, 50 °C, 37 °C, 4 °C, and −20 °C can be identified using preliminary test while burnt blood stain cannot. Seminal stains exposed to temperature grades 37 °C, 4 °C, and −20 °C can be identified by Florence test while those exposed to 100 °C, 50 °C, and burn cannot. Blood and seminal stains exposed to temperature grades 100 °C, 50 °C, and burn show marked reduction in DNA concentration while maximum DNA conc could be recovered from stains exposed to temperature grade temperature. Both blood and seminal DNA was affected only in case of burn without significant difference between THO1 and Amelogenin primers. Conclusion: High environmental temperature affect the quantity of extracted DNA from different stains but less effect on the quality of extracted DNA. Burn affects both preliminary test, DNA quantity, and quality in stains.

Evaluation of the relationship between the detectability of seminal stains on laundered fabric and stain age

In some cases of sexual assault that are not reported to judicial authorities within a certain time, it is important to detect and identify seminal stains on laundered fabrics. In this study, we aimed to reveal the effect of the time from staining to laundering on the detectability and identification of seminal stains on laundered clothes. A total of 180 pieces of fabric (four different colours and five different types) were stained with seminal fluids, and three different lag times (12 hours, 1 week and 1 month) from staining to laundering were used. Three different laundering protocols were applied to these fabrics after staining. The built-in camera of the Mobile Multispectral UV-VIS-IR Imaging System® was used to take photos (1260 in total) of the stains with seven different wavelength and filter options, and the obtained images were evaluated. The Seratec® PSA Semiquant test was used to analyse the presence of prostate-specific antigen (PSA) in the seminal stains laundered after different lag times. We observed that in examining with the forensic light source (FLS) system, the time from staining to laundering affected the detectability of seminal stains on pieces of cloth. The best fluorescence was obtained in the examination of semen-stained fabric with FLS, particularly when the fabric was not laundered for one month after staining. On the other hand, the time from staining to laundering had a more limited effect on PSA test positivity than on the results of the examination with FLS.

Sexual Assault Forensic Examination in adult and child cases: Is Colposcopy Really Necessary?

Sexual assault is a complex situation with medical, psychological, and legal aspects. Victims should be examined by a specially trained medico-legal examiner to collect evidence and avoid multiple examinations. The use of colposcopy in child and adult sexual assault cases is becoming increasingly more widespread however; it is still not a routine aspect of all examinations in most countries. The present study aimed to evaluate the importance of using the colposcope in the examination of the sexual assault cases admitted to the violence against women and child clinic in the Forensic Medicine Authority in Egypt. The study included (150) cases, divided into two groups according to age: Group A (1 to 18 years) (124) male and female children and Group B (19-40 years) (26) females. -General, then local examination with the naked eye and colposcopy had been performed. Internal genitalia was examined by using disposable plastic Casco in adult non-virgin victims only. -Vaginal and anal swabs were collected for the detection of seminal stains. The results of the colposcopic examination revealed a significant difference in both negative and positive results when compared to the other methods of examination (naked eye, swabs, and clothes examination). Colposcopic magnification power with high resolution and illumination light permits to discover microtrauma which may not be discovered with a normal examination by naked eyes. Colposcope seems to be an important noninvasive tool for the examination of children and adults when sexual abuse is suspected. Its documentation could allow for supervision, teaching, and second opinions in an ethically difficult setting. The colposcopic examination should be introduced to all forensic departments in Egypt to be used as a routine aspect of all sexual assault examinations. Future studies are recommended to be conducted on a national scale. Keywords: Sexual assault; Colposcope; Toluidine blue dye; Examination