An Alu-based, MGB Eclipse real-time PCR method for quantitation of human DNA in forensic samples

The forensic community needs quick, reliable methods to quantitate human DNA in crime scene samples to replace the laborious and imprecise slot blot method. A real-time PCR based method has the possibility of allowing development of a faster and more quantitative assay. Alu sequences are primate-specific and are found in many copies in the human genome, making these sequences an excellent target or marker for human DNA. This paper describes the development of a real-time Alu sequence-based assay using MGB Eclipse primers and probes. The advantages of this assay are simplicity, speed, less hands-on-time and automated quantitation, as well as a large dynamic range (128 ng/microL to 0.5 pg/microL).     

Virtopsy: postmortem minimally invasive angiography using cross section techniques--implementation and preliminary results

Postmortem investigation is increasingly supported by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). This led to the idea to implement a noninvasive or minimally invasive autopsy technique. Therefore, a minimally invasive angiography technique becomes necessary, in order to support the vascular cross section diagnostic. Preliminary experiments investigating different contrast agents for CT and MRI and their postmortem applicability have been performed using an ex-vivo porcine coronary model. MSCT and MRI angiography was performed in the porcine model. Three human corpses were investigated using minimally invasive MSCT angiography. Via the right femoral artery a plastic tube was advanced into the aortic arch. Using a flow adjustable pump the radiopaque contrast agent meglumine-ioxithalamate was injected. Subsequent MSCT scanning provided an excellent anatomic visualization of the human arterial system including intracranial and coronary arteries. Vascular pathologies such as calcification, stenosis and injury were detected. Limitations of the introduced approach are cases of major vessel injury and cases that show an advanced stage of decay.     

SNPs and MALDI-TOF MS: tools for DNA typing in forensic paternity testing and anthropology

DNA markers used for individual identification in forensic sciences are based on repeat sequences in nuclear DNA and the mitochondrial DNA hypervariable regions 1 and 2. An alternative to these markers is the use of single nucleotide polymorphisms (SNPs). These have a particular advantage in the analysis of degraded or poor samples, which are often all that is available in forensics or anthropology. In order to study the potential of SNP analysis in these fields, 41 SNPs were selected on the basis of following criteria: conservation, lack of phenotypic expression, and frequency of occurrence in populations. Thirty-six autosomal SNPs were used for genotyping 21 inclusionary and 3 exclusionary paternity cases. The behavior of 5 X-chromosome SNPs was analyzed in a French representative population. Our approach to SNP typing is a multiplex PCR based amplification followed by simultaneous detection by primer extension (PEX) analyzed by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). The selected autosomal SNPs showed independent inheritance and gave clear results in paternity investigation. All X-SNPs were useful as both paternity and identification markers. PEX and MALDI-TOF MS, with their high sensitivity, precision and speed, gave a powerful method for forensic and anthropological exploitation of biallelic markers.     

Fatal pulmonary cement embolism following percutaneous vertebroplasty (PVP)

A case of fatal pulmonary embolism with acrylic cement occuring during a percutaneous vertebroplasty on account of a fracture of L1 is described. Autopsy confirmed the presence of large amounts of surgical cement in the paravertebral venous system and in the pulmonary arteries. This rare complication occurred because perivertebral venous cement migration was not recognized during vertebroplasty. To our knowledge, this is the first case of fatal pulmonary embolism caused by surgical cement following a percutaneous vertebroplasty.     

Estimation of postmortem interval in real cases based on experimentally obtained entomological evidence

Using the entomological evidence obtained in several forensic cases analyzed in our laboratory for comparison, we evaluated the results of an experimental study carried out in a semiurban setting to determine the structure of the sarcosaprophagous fauna from a Mediterranean region of SE Spain. In all, 18 orders of arthropods were collected. The summarized experimental results refer to the most important taxa for estimating the postmortem interval. Thus, the seasonal character of certain Diptera species, such as Phaenicia sericata, Calliphora vicina, Chrysomya albiceps and Musca domestica, is cited. Among the Coleoptera, the role of Dermestidae as a necrophagous species, and of Staphylinidae and Histeridae as necrophilous, or Cleridae, Tenebrionidae and Nitidulidae as omnivorous, as well as their appearance on the corpse, is described. Among the Hymenoptera, Formicidae were as the most abundant group, acting as omnivores and not apparently related to any particular decomposition stage. The real cases are discussed using data from the literature and the experimentally obtained results. In every case, the most relevant factors for estimating PMI are briefly discussed, mentioning, when possible, the relation with the experimental results. We confirm the significance of the experimental results because they seem to be applicable to actual forensic cases, the details of which enlarge our very little knowledge on the subject in the Iberian Peninsula. The importance of regional faunistic studies of the sarcosaprophagous arthropod community, the results of which may be applied to forensic practice, is mentioned.     

Y-chromosome STR haplotypes and alleles in the ethnic group of Polish Tatars residing in the Northeastern Poland

Haplotype and allele frequencies for eight Y-STRs were determined in a population sample of the ethnic group of Polish Tatars residing in the Northeastern Poland. A total of 125 unrelated males produced 101 different haplotypes. Thirteen haplotypes occurred more than once, while 88 haplotypes were unique. The observed gene diversity was 0.9638. The ethnic group of Polish Tatars can be distinguished from the autochthonous Poles based on AMOVA estimates in all the analyzed systems except DYS385.