Hochmeister M N, Whelan M, Borer U V, Gehrig C, Binda S, Berzlanovich A, Rauch E, Dirnhofer R
Institute of Legal Medicine, University of Berne, Switzerland.
J Forensic Sci. 1997 Mar;42(2):316-9.
Toluidine blue is an important tool to detect and document genital and perianal injuries following sexual assault. Application of toluidine blue dye and its subsequent removal from unstained areas by means of a destaining reagent, such as diluted acetic acid or a lubricant has been shown to increase the detection rate of posterior fourchette lacerations from 16% to 40% in adult rape victims. Currently, limited information on toluidine blue positive findings in sexually active control groups imposes some limitation on the interpretation of these injuries. Because injuries could otherwise be attributed to improper handling of an examination speculum or the improper insertion of the examining finger, the toluidine blue test should be performed prior to any digital or speculum examination and thus prior to the collection of forensic evidence. For forensic DNA identity testing, it becomes pertinent to determine whether toluidine blue and the destaining reagents used in a sexual assault examination have an adverse effect on the recovery of high molecular weight DNA from postcoital vaginal swabs and thereby have an impact on restriction fragment length polymorphism (RFLP) analysis or PCR-based tests. It is known that some of the lubricants used can have a destructive effect on sperm motility. In order to investigate the potential effects, postcoital vaginal swabs were taken 6 h after sexual intercourse and exposed directly to 1% toluidine blue in aqueous solution, 1-10% acetic acid, and various surgical and vaginal lubricants. Subsequently, the DNA was isolated and DNA identity typing (RFLP and PCR-based) was performed. The results demonstrate, that these reagents have no negative effect on the ability to obtain DNA profiles, either RFLP or PCR-based, from shallow and deep vaginal swabs. The quantity and quality of extractable high molecular weight DNA obtained was comparable with that from uncontaminated postcoital vaginal swabs. RFLP patterns and PCR-based typing results on the D1S80, HUMTH01, TPOX, and CSF1PO loci were consistent with the uncontaminated control swabs and the corresponding whole blood samples of the donors. Therefore, evidentiary material inadvertently contaminated with these reagents can be successfully typed.
甲苯胺蓝是检测和记录性侵犯后生殖器及肛周损伤的重要工具。在成年强奸受害者中，应用甲苯胺蓝染料，随后通过诸如稀释乙酸或润滑剂等脱色剂从未染色区域去除染料，已显示可将后穹窿撕裂伤的检出率从16%提高到40%。目前，关于性活跃对照组中甲苯胺蓝阳性结果的信息有限，这对这些损伤的解释造成了一定限制。由于这些损伤否则可能归因于检查窥器使用不当或检查手指插入不当，甲苯胺蓝试验应在任何指检或窥器检查之前进行，从而在收集法医证据之前进行。对于法医DNA同一性检测，确定在性侵犯检查中使用的甲苯胺蓝和脱色剂是否对性交后阴道拭子中高分子量DNA的回收有不利影响，进而对限制性片段长度多态性（RFLP）分析或基于PCR的检测有影响，就变得至关重要。已知一些使用的润滑剂会对精子活力产生破坏作用。为了研究潜在影响，在性交后6小时采集性交后阴道拭子，并将其直接暴露于1%的甲苯胺蓝水溶液、1 - 10%的乙酸以及各种手术和阴道润滑剂中。随后，分离DNA并进行DNA同一性分型（基于RFLP和PCR）。结果表明，这些试剂对从浅层和深层阴道拭子中获得基于RFLP或PCR的DNA图谱的能力没有负面影响。所获得的可提取高分子量DNA的数量和质量与未受污染的性交后阴道拭子相当。在D1S80、HUMTH01、TPOX和CSF1PO基因座上的RFLP图谱和基于PCR的分型结果与未受污染的对照拭子以及供体相应的全血样本一致。因此，被这些试剂意外污染的证据材料可以成功分型。
