The use of photographs to record variation in bruising response in humans.

There is considerable value in developing tools capable of accurately and reliably determining when bruises were inflicted in humans. Previous work has focused on the visual changes observed in a bruise as the injury develops and heals. However, due to variables such as how and where on the body the bruise was inflicted, differing tissue compositions at the injured skin site between individuals and inter- and intra-observer variation; a technique sufficiently robust for use in a clinical or medicolegal setting has not yet been identified. In this study we present a series of photographs taken under controlled conditions illustrating standardised bruises induced on participants using a weight dropping mechanism. We show that variation in the appearance of bruises over time across individuals is large and, although photography may be a suitable technique for the recording of injuries, it is not sufficiently reliable for determining the age of a bruise.

Efficacy of several candidate protein biomarkers in the differentiation of vaginal from buccal epithelial cells.

Currently, there is no accurate method to differentiate vaginal epithelial cells from buccal epithelial cells in biological samples typically encountered in forensic casework. This study tested the expression of a selection of candidate proteins in buccal and vaginal epithelial cells. We investigated six candidate biomarkers, such as loricrin, vimentin, stratifin, cytokeratin 4, cytokeratin 13, small proline-rich protein 2, and involucrin, using Western blot analysis on whole protein extracts and immunohistochemistry (IHC) on intact cells in an attempt to identify cell-specific markers that would differentiate these cells by microscopy. Involucrin, loricrin, and stratifin showed differential expression during Western blot analysis and were carried through to IHC. Although proteins unique to vaginal epithelial cells and buccal epithelial cells were not identified from among the proteins tested, the increased expression levels of two proteins, loricrin and stratifin in vaginal cells, when compared to buccal cells, do provide encouraging results in the search for epithelial cell-specific markers.

Effects of histological staining on the analysis of human DNA from archived slides.

Archived slides of cell smears treated with histological stains for sperm detection are often the only source of DNA available when cold cases are reopened. There have been conflicting reports as to the negative effects of particular histological stains on DNA recovery and quality from human cells, making stain selection an important consideration for forensic laboratories. This study investigates the effect of several staining systems on DNA recovery from histological slide samples stored from 0 to 10 weeks. DNA profiles obtained after analysis of these samples with AmpFlSTR(®) Identifiler™ and increased cycle AmpFlSTR(®) SGM Plus™ short tandem repeat (STR) profiling systems and the effects that these stains have on DNA quantity and quality over time are described. Results indicate that Christmas Tree and Hematoxylin and Eosin stains do not have significantly different effects on DNA quality after 10-week storage of slides. This research will assist scientists to select staining systems that have minimal deleterious effects on the DNA recovered.