Analysis of postmortem DNA degradation by single-cell gel electrophoresis

One of the most important longstanding problems in the field of forensic medicine is the determination of the time of death upon the discovery of a possible homicide victim. With a majority of homicide victims discovered within the first 48h, it is critically important to be able to determine time of death quickly, and with accuracy and precision. Current methods of determining postmortem interval (PMI) vary, but none can provide better than an 8-h window time estimate. In this paper, the potential application of single-cell gel electrophoresis (SCGE), also known as the comet assay, to evaluate postmortem cell death processes, specifically nuclear DNA fragmentation, is assessed. Upon the death of an organism, internal nucleases contained within the cells should cause chromosomal DNA to degrade into increasingly smaller fragments over time, and if these fragments can be isolated and visualized, the fragmentation should prove to be measurable and quantifiable. An original study providing proof of the concept of postmortem DNA fragmentation between early and late time periods was conducted using human leukocytes. With an established trend seen in the leukocyte results, this study was then expanded using a porcine animal model, over a longer time period, with more frequent time-points evaluated. DNA degradation in all samples was revealed by SCGE and quantified by the use of DNA-specific quantitative stains, as measured by digital camera affixed to a microscope. The comet 'tail-moment' gave a measure of the proportion of fragmented to non-fragmented DNA, while the 'tail-length' provided the relative size of degraded DNA fragments. In both models, an increase in DNA fragmentation was found to correlate with an increased PMI from 0 to 56h postmortem, as evaluated by comet-tail-moment and by comet-tail-length, with tail-length providing the strongest statistical correlation, based upon regression analysis. The postmortem DNA fragmentation observed in this study, reveals a sequential, time-dependent process with the potential for use as a predictor of PMI in homicide cases.     

Fairness and Rejection in the Ultimatum Bargaining Game

The ultimatum game is a standard instrument for laboratory experimentalists.It has been replicated in a large number of environments andpoints to special considerations for fairness. Although it hasbeen popular in the experimental community, researchers havenot harnessed all the statistical power they should to evaluatethe dynamics at work in this type of a bargaining game. Thisresearch uses two planned treatments, the first involving asignaling condition concerning a subject's "type," and the seconda price effect built into the structure of the game. We findthat there are no significant main effects as a result of thesignaling condition of a subject's type, but that there arestrong effects as a result of the different payoff parameters.Using a variety of multivariate models we find important, nonobviousinteractions with the gender of the subjects. The lesson thatwe take away from this research is that experimentalists canlearn more from data collected in the tightly controlled laboratoryenvironment by using statistical techniques that complementtheir research designs.     

STR-typing of human DNA from human fecal matter using the QIAGEN QIAamp stool mini kit

The purpose of this study was to compare the effectiveness of the QIAGEN QIAamp Stool Mini Kit against a standard phenolchloroform procedure for the extraction, quantitation, and STR-typing of human nuclear DNA from human feces. Stools from six subjects were sampled by swabbing and excision. Samples extracted with the QIAamp kit gave a wide range of DNA yields, whereas those extracted by the organic method yielded no DNA. DNA was not recovered from one subject's stools by either procedure. The QIAamp extracts were amplified with the Profiler Plus and COfiler kits, and PCR inhibition was observed with DNA extracts that were further concentrated. Substitution of water or TE-4 for the QIAamp elution buffer eliminated most, if not all, of the inhibition. A modified QIAamp procedure was used to extract thirty samples, which were subjected to one of five environmental conditions. DNA was recovered from all of these samples, and typing results were obtained on 93% of the samples.     

A forensic laboratory tests the Berkeley microfabricated capillary array electrophoresis device

Miniaturization of capillary electrophoresis onto a microchip for forensic short tandem repeat analysis is the initial step in the process of producing a fully integrated and automated analysis system. A prototype of the Berkeley microfabricated capillary array electrophoresis device was installed at the Virginia Department of Forensic Science for testing. Instrument performance was verified by PowerPlex 16 System profiling of single source, sensitivity series, mixture, and casework samples. Mock sexual assault samples were successfully analyzed using the PowerPlex Y System. Resolution was assessed using the TH01, CSF1PO, TPOX, and Amelogenin loci and demonstrated to be comparable with commercial systems along with the instrument precision. Successful replacement of the Hjerten capillary coating method with a dynamic coating polymer was performed. The accurate and rapid typing of forensic samples demonstrates the successful technology transfer of this device into a practitioner laboratory and its potential for advancing high-throughput forensic typing.     

Domestic violence and dependency courts: the Greenbook demonstration experience

This field study reports on a cross-site evaluation of dependency courts in communities receiving federal funding to implement the Greenbook initiative, a multisite demonstration for community improvement of coordinated responses to families victimized by domestic violence and child maltreatment. This article focuses on the dependency court, where child maltreatment cases are heard, specifically court participation in collaborative activities and court practice improvements. Findings indicate that perceptions of judicial leadership varied considerably by site. Cross-training appeared to increase over time, particularly with court staff. Collaborative efforts emerged across the Greenbook initiative with regard to the courts, and some innovative practices appeared within Greenbook sites, such as separate case plans for perpetrators and victims of violence in families, reducing the likelihood of controversial failure to protect charges. Results also highlight challenges inherent in changing court practices. Research and practice implications are discussed, focusing on relevance to other communities attempting to work collaboratively with the court system.     

PTSD compromises battered women's future safety

Intimate partner violence continues to be a social crisis that results in a complex array of physical and mental health problems. Although resources to counteract the effects of the violence are sometimes available, the posttrauma sequelae may prevent access by those in need. Using the Chicago Women's Health Risk Study, a naturalistic longitudinal study of 320 abused women, the current study examined the impact of posttraumatic stress disorder (PTSD) and depression on battered women's safety at follow-up. Participants completed both a baseline and follow-up interview, including data on abuse experiences. Results suggest symptoms of PTSD predict severity of violence at follow-up over the impact of help-seeking behaviors, perceived helpfulness of these behaviors, and social support. Implications of results are discussed.