Comparison between MACSprep™ forensic sperm microbead kit and Erase Sperm Isolation kit for the enrichment of sperm fractions recovered from sexual assault samples

International Journal of Legal Medicine - Sexual assault samples often contain mixtures of cells coming from at least two donors. Ideally, one would need to separate the cells into two cellular...     

Assessing PreCR™ repair enzymes for restoration of STR profiles from artificially degraded DNA for human identification

Forensic scientists have used several approaches to obtain short tandem repeat (STR) profiles from compromised DNA samples, including supplementing the polymerase chain reaction (PCR) with enhancers and using procedures yielding reduced-length amplicons. For degraded DNA, the peak intensities of the alleles separated by electrophoresis generally decrease as the length of the allele increases. When the intensities of the alleles decrease below an established threshold, they are described as drop-outs, thus contributing to a partial STR profile. This work assesses the use of repair enzymes to improve the STR profiles from artificially degraded DNA. The commercial PreCR™ repair kit of DNA repair enzymes was tested on both purified DNA and native DNA in body fluids exposed to oxidizing agents, hydrolytic conditions, ultraviolet (UV) and ionizing radiation, and desiccation. The strategy was to restrict the level of DNA damage to that which yields partial STR profiles in order to test for allele restoration as opposed to simple allele enhancement. Two protocols were investigated for allele restoration: a sequential protocol using the manufacturer's repair procedure and a modified protocol reportedly designed for optimal STR analysis of forensic samples. Allele restoration was obtained with both protocols, but the peak height appeared to be higher for the modified protocol (determined by Mann–Kendall Trend Test). The success of the approach using the PreCR™ repair enzymes was sporadic; it led to allele restoration as well as allele drop-out. Additionally, allele restoration with the PreCR™ enzymes was compared with restoration by alternative, but commonly implemented approaches using Restorase™, PCRBoost™, bovine serum albumin (BSA) and the Minifiler™ STR system. The alternative methods were also successful in improving the STR profile, but their success also depended on the quality of the template encountered. Our results indicate the PreCR™ repair kit may be useful for restoring STR profiles from damaged DNA, but further work is required to develop a generalized approach.     

Development and validation of a novel method “SpermX™” for high throughput differential extraction processing of sexual assault kits (SAKs) for DNA analysis

The Sperm X method uses a nanotechnology derived polymer membrane that functions as a separation medium to effectively trap sperm cells while enabling efficient flow through of the digested epithelial cell DNA. This specialized membrane enabled development of a method that could significantly increase a forensic laboratory’s ability to obtain male sperm fraction DNA profiles. The SpermX device provides a rapid, reproducible procedure that is easy to implement in a single-tube format as well as high-throughput truly automated hands-free workflows.Validation studies, performed using the manual SpermX method, include sensitivity, stability, precision (reproducibility and repeatability), mixtures, and a method comparison to the traditional differential extraction. Sensitivity and method comparison studies demonstrated a wide range of sperm cells, from a high of over 2.78 million cells (9158 ng) to a low of 25 cells (83 pg), can be trapped by the SpermX membrane. Stability studies on various substrates (i.e., carpet, cotton, denim, polyester, and silk) and degraded semen gave the expected male DNA profiles. Data from the same operator and a different operator were consistent with low variance. Mixtures, with ratios ranging from approximately 10:1–18182:1, created to simulate real casework type samples including buccal/semen, vaginal epithelial/semen, and post coital swabs at different time intervals, were tested. A comparison of the SpermX method to the conventional differential extraction method resulted in comparable probative male profile allelic data and associated statistical probabilities. For low level sperm samples, down to 25 sperm cells (83 pg), the SpermX method outperformed the conventional differential extraction with more genotypic information and associated probabilities.     

Striated abrasions from a knife with non-serrated blade—identification of the instrument of crime on the basis of an experiment with material evidence

This paper presents an experiment with a knife seized as material evidence in a homicide case. The reason for the experiment was the necessity to determine whether the injuries of the deceased could have been inflicted with this instrument since in the course of the investigation doubt arose as to the origin of linear, parallel scratches around one of the wounds and on the abdominal integuments suggesting a serrated blade. The knife found near the crime scene had a smooth blade and small serrations only on the borderline between its blade and hilt. However, the performed experiment showed that if the knife is directed towards the integuments of the body in a special way, its serrations, even though not located on the blade itself, may leave such striated marks on the body, as those found during the autopsy, suggesting their origin from a serrated blade.     

Genetic data for PowerPlex 21™ autosomal and PowerPlex 23 Y-STR™ loci from population of the state of Uttar Pradesh,India

International Journal of Legal Medicine - In the present study, the statistical forensic parameters were evaluated for the loci present in PowerPlex 21 autosomal and PowerPlex 23 Y-STR multiplex...     

Does the punishment fit the crime? Judicial sentencing in adolescent and adult sexual assault cases

This is the first Canadian study to focus directly on whether factors commonly identified as reflecting the seriousness of a sexual assault are noted by judges, and in turn, related to the severity of the sentences they impose. We examined adolescent and adult female sexual assault cases heard in Ontario between 1993 and 2001. Two hundred twenty-one cases were identified using Quicklaw, Canada's most comprehensive on-line legal information system, with data extracted onto a coding instrument. In 201 (91%) of these cases, a perpetrator had been sentenced to prison or jail. Judges reported that in a substantial proportion of these women they had been penetrated (67%), forced (49%), coerced (50%), physically injured (33%), and psychologically harmed (65%). However, only two of the six offence seriousness factors examined were associated with a prison versus jail sentence: the occurrence of vaginal and/or anal penetration and the threat or use of a weapon(s).     

The medical and ethical aspects of photography in the sexual assault examination: why does it offend?

This paper reviews the literature in respect to the photo-colposcopic examination of anogenital injury in the sexually assaulted child, considered to be the 'gold standard' of examination, and how this compares with gross visualisation, still the standard procedure in adult examinations. It then examines the claim that, because the presence of injury does not provide a distinction between consensual and non-consensual intercourse in adults, photo-documentation is unnecessary medically and constitutes an invasive procedure which is ethically unacceptable. The paper questions whether the unwillingness of forensic physicians to extend photo-colposcopy to the examination of adult victims is related more to political and gender issues than to claims made on ethical and medical grounds, and concludes that any move to ban anogenital photography in adult forensic examinations (currently under consideration in the author's own jurisdiction) would possibly constitute an interference with independent clinical judgment and an incursion into the patient's right to evidence-based medicine.     

Does the punishment fit the crime? Judicial sentencing in adolescent and adult sexual assault cases

This is the first Canadian study to focus directly on whether factors commonly identified as reflecting the seriousness of a sexual assault are noted by judges, and in turn, related to the severity of the sentences they impose. We examined adolescent and adult female sexual assault cases heard in Ontario between 1993 and 2001. Two hundred twenty-one cases were identified using Quicklaw, Canada's most comprehensive on-line legal information system, with data extracted onto a coding instrument. In 201 (91%) of these cases, a perpetrator had been sentenced to prison or jail. Judges reported that in a substantial proportion of these women they had been penetrated (67%), forced (49%), coerced (50%), physically injured (33%), and psychologically harmed (65%). However, only two of the six offence seriousness factors examined were associated with a prison versus jail sentence: the occurrence of vaginal and/or anal penetration and the threat or use of a weapon(s).     

Inter-laboratory evaluation of SNP-based forensic identification by massively parallel sequencing using the Ion PGM™

Next generation sequencing (NGS) offers the opportunity to analyse forensic DNA samples and obtain massively parallel coverage of targeted short sequences with the variants they carry. We evaluated the levels of sequence coverage, genotyping precision, sensitivity and mixed DNA patterns of a prototype version of the first commercial forensic NGS kit: the HID-Ion AmpliSeq™ Identity Panel with 169-markers designed for the Ion PGM™ system. Evaluations were made between three laboratories following closely matched Ion PGM™ protocols and a simple validation framework of shared DNA controls. The sequence coverage obtained was extensive for the bulk of SNPs targeted by the HID-Ion AmpliSeq™ Identity Panel. Sensitivity studies showed 90–95% of SNP genotypes could be obtained from 25 to 100 pg of input DNA. Genotyping concordance tests included Coriell cell-line control DNA analyses checked against whole-genome sequencing data from 1000 Genomes and Complete Genomics, indicating a very high concordance rate of 99.8%. Discordant genotypes detected in rs1979255, rs1004357, rs938283, rs2032597 and rs2399332 indicate these loci should be excluded from the panel. Therefore, the HID-Ion AmpliSeq™ Identity Panel and Ion PGM™ system provide a sensitive and accurate forensic SNP genotyping assay. However, low-level DNA produced much more varied sequence coverage and in forensic use the Ion PGM™ system will require careful calibration of the total samples loaded per chip to preserve the genotyping reliability seen in routine forensic DNA. Furthermore, assessments of mixed DNA indicate the user’s control of sequence analysis parameter settings is necessary to ensure mixtures are detected robustly. Given the sensitivity of Ion PGM™, this aspect of forensic genotyping requires further optimisation before massively parallel sequencing is applied to routine casework.     

A comparison of ABAcard® p30 and RSID™-Semen test kits for forensic semen identification

The screening and confirmatory tests available to a forensic laboratory allow evidence to be examined for the presence of bodily fluids. With the majority of evidence being submitted involving sexual assaults, it is important to have confirmatory tests for the identification of semen that are straightforward, quick, and reliable. The purpose of this study was to compare two commonly used semen identification kits utilized by forensic laboratories: ABAcard^® p30 and Rapid Stain Identification of Human Semen (RSID?-Semen). These kits were assessed with aged semen stains, fresh and frozen post-vasectomy semen, post-coital samples collected on different substrates, post-vasectomy semen mixed with blood, saliva, and urine, a series of swabs collected at increasing time intervals after sexual intercourse, and multiple non-semen samples. The test kits were compared on the basis of sensitivity, specificity, and the cost and time effectiveness of each protocol. Overall, both semen identification tests performed well in the studies. Both kits proved specificity for identifying semen, however the ABAcard^® p30 test surpassed the RSID?-Semen test in sensitivity, cost per test, and simplified test protocol.     

MVP™ Micro Vascular Plug Systems for the Treatment of Pulmonary Arteriovenous Malformations

CardioVascular and Interventional Radiology - To describe our institutional experience with MVP™ micro vascular plug systems for the treatment of pulmonary arteriovenous malformations...     

Developmental validation of STRmix™ NGS,a probabilistic genotyping tool for the interpretation of autosomal STRs from forensic profiles generated using NGS

We describe the developmental validation of the probabilistic genotyping software – STRmix™ NGS – developed for the interpretation of forensic DNA profiles containing autosomal STRs generated using next generation sequencing (NGS) also known as massively parallel sequencing (MPS) technologies. Developmental validation was carried out in accordance with the Scientific Working Group on DNA Analysis Methods (SWGDAM) Guidelines for the Validation of Probabilistic Genotyping Systems and the International Society for Forensic Genetics (ISFG) recommendations and included sensitivity and specificity testing, accuracy, precision, and the interpretation of case-types samples. The results of developmental validation demonstrate the appropriateness of the software for the interpretation of profiles developed using NGS technology.     

Accuracy of the SenseWear Armband™ during ergocycling

The present study aims to show the accuracy of a portable motion sensor, the SenseWear Armband, for the estimation of energy expenditure vs. energy expenditure measured by indirect calorimetry during ergocycling. 31 healthy adults (52% women; age: 26.7±6.3 years; Body Mass Index: 23.9±3.3?kg/m2) completed a 45-min ergocycling session at 50% of their VO2(peak). Despite a significant underestimation of 18.7±13.2?kcal during the first 10?min of the activity (T=5.06; p<0.001), we observed an overall good agreement between energy expenditure estimated by the SenseWear Armband during ergocycling and indirect calorimetry (260.3±80.1 vs. 287.8±97.1?kcal, respectively) (T=-2.148; p=0.04) and a significant intra-class correlation (r=0.81; p<0.001). The results of the present study indicate that the SenseWear Armband underestimated energy expenditure during a 45-min ergocycling session at a 50% VO2(peak) intensity, mainly during the first 10?min. Underestimation at the onset of the activity warrants further research.     

Forensic differentiation between peripheral and menstrual blood in cases of alleged sexual assault—validating an immunochromatographic multiplex assay for simultaneous detection of human hemoglobin and D-dimer

International Journal of Legal Medicine - Sexual assault is a serious offense and identification of body fluids originating from sexual activity has been a crucial aspect of forensic investigations...     

Use of the Trellis™ Peripheral Infusion System for Enhancement of rt-PA Thrombolysis in Acute Lower Limb Ischemia

The Trellis Peripheral Infusion System is an over-the-wire 0.035 guidewire compatible device, designed to isolate a region of the peripheral vasculature to allow for lytic drug infusion and dispersion. We used it successfully through a percutaneous approach in two cases of acute thrombosis of a native lower limb artery. The total amount of rt-PA used was 12 and 9 mg, respectively and was delivered through bolus injections obviating the need for a supplementary continuous infusion of the agent. The time for dissolution of thrombus was 45 and 35 minutes, respectively. No complications were observed.