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.     

THE FIFTH WORLD CONGRESS ON FAMILY LAW AND THE RIGHTS OF CHILDREN AND YOUTH

Editor's note on the 5^th World Congress on Family Law and Children's Rights held in Halifax Nova Scotia, August 23–26, 2009     

俄中美三角中的俄罗斯东部地区

21世纪初西伯利亚和远东的地理政治与地理经济作用正逐渐增长,太平洋地区国家对该地区的兴趣和关注也在飞速增长.莫斯科、北京和华盛顿在广袤的西伯利亚和远东的利益将如何部署,这种部署会建立在合作的基础之上还是会成为引发各种冲突表现的主要原因?它将怎样影响在太平洋地区和全世界的国际关系?一种关于"俄中美三角关系"在西伯利亚和远东广大地区相互作用之前景的观点得出了关于潜在冲突的结论,这种潜在的冲突埋伏在三方态度和利益的差异上.在太平洋地区潜在的国家利益和全球及地区力量分配的改变可能会给三方利益和立场的确定带来调整.     

Toxicological analysis after asphyxial suicide with helium and a plastic bag

A 23-year-old man was found on a raised hide in lying position, the head wrapped in a plastic bag connected with a helium gas cylinder by a polypropylene tube. The autopsy did not show any specific findings nor did the routine toxicological analysis reveal significant information regarding the cause of death (BAC 0.9 mg/g, diphenhydramine 0.81 μg/ml in heart serum). For the detection of helium in the lungs, gas samples from both lungs were collected by a method ensuring minimal dilution. Gas analyses were performed using a GC–MS with a split–splitless injector and a headspace syringe. As carrier gas the commonly used helium was replaced by nitrogen. Helium was found in clearly elevated concentrations in gas samples from both lungs. Therefore, suffocation by breathing helium enriched, and thus oxygen deficient atmosphere, can strongly be assumed as the cause of death.