A novel histological technique for distinguishing between epithelial cells in forensic casework

There are a number of forensic cases in which the identification of the epithelial cell type from which DNA originated would provide important probative evidence. This study aimed to develop a technique using histological staining of fixed cells to distinguish between skin, buccal and vaginal epithelium. First, 11 different stains were screened on formalin-fixed, wax-embedded cells from five women. Samples were analysed qualitatively by examining staining patterns (colour) and morphology (absence or presence of nuclei). Three of the staining methods – Dane's, Csaba's and Ayoub-Shklar – were successful in distinguishing skin epithelial cells from buccal and vaginal. Second, cells were smeared directly onto slides, fixed with one of five fixatives and stained with one of the three stains mentioned above. Methanol fixation, coupled with the Dane's staining method, specific to keratin, was the only technique that distinguished between all three cell types. Skin cells stained magenta, red and orange and lacked nuclei; buccal cells stained predominantly orange–pink with red nuclei; while vaginal cells stained bright orange with orange nuclei and a blue extracellular hue. This staining pattern in vaginal cells was consistent in samples collected from 50 women aged between 18 and 67. Identification of cell type from unlabelled micrographs by 10 trained observers showed a mean success rate of 95%. The results of this study demonstrate that histological staining may provide forensic scientists with a technique for distinguishing between skin, buccal and vaginal epithelial cells and thus would enable more conclusive analyses when investigating sexual assault cases.     

Intention to Stop Bullying following a Condemning,Empathy-Raising,or Combined Message from a Teacher – Do Students’ Empathy and Callous-Unemotional Traits Matter?

Journal of Youth and Adolescence - Knowing which intervention strategies work best and for which student is essential for teachers when they intervene in cases of bullying. The effects of...     

Female serial killers in the United States: means,motives, and makings

Most studies that have focused on female serial killers (FSKs), although informative, have examined limited sample sizes. We consulted mass media reports of demographics, motives, methods, mental health, and victim characteristics of 64 FSKs who committed their crimes in the US from 1821 to 2008. Consistent with other studies, our data showed that FSKs were typically White, educated, have been married, and held a caregiving role (e.g. mother, health care worker). Nearly 40% of FSKs in this sample experienced some form of mental illness. Their most common motive for murder was financial gain, and their most common method of killing was poisoning. FSKs knew all or most of their victims, and most were related to their victims. In all cases, FSKs targeted at least one victim who was a child, elderly, or infirm – those who had little chance of fighting back. We interpret these killers’ behaviors from clinical and evolutionary angles.