Forensic Diagnostics Research Articles

Microfluidic Paper-Based Analytical Devices (μPADs) and Micro Total Analysis Systems (μTAS): Development, Applications and Future Trends

Microfluidic paper-based analytical devices and micro total analysis systems are relatively new group of analytical tools, capable of analyzing complex biochemical samples containing macromolecules, proteins, nucleic acids, toxins, cells or pathogens. Within one analytical run, fluidic manipulations like transportation, sorting, mixing or separation are available. Recently, microfluidic devices are a subject of extensive research, mostly for fast and non-expensive biochemical analysis but also for screening of medical samples and forensic diagnostics. They are used for neurotransmitter detection, cancer diagnosis and treatment, cell and tissue culture growth and amplification, drug discovery and determination, detection and identification of microorganisms. This review summarizes development history, basic fabrication methods, applications and also future development trends for production of such devices.

Can clinical CT data improve forensic reconstruction?

In accidents resulting in severe injuries, a clinical forensic examination is generally abandoned in the initial phase due to high-priority clinical needs. However, in many cases, data from clinical computed tomography (CT) examinations are available. The goals of this prospective study were (a) to evaluate clinical CT data as a basis for forensic reconstruction of the sequence of events, (b) to assess if forensic radiological follow-up reading improves the forensic diagnostic benefit compared to the written clinical radiological reports, and (c) to evaluate if full data storage including additional reconstructed 0.6-mm slices enhances forensic analysis. Clinical CT data of 15 living individuals with imaging of at least the head, thorax, and abdomen following polytrauma were examined regarding the forensic evaluation of the sequence of events. Additionally, 0.6-mm slices and 3D images were reconstructed for forensic purposes and used for the evaluation. At the forensic radiological readings, additional traumatic findings were observed in ten of the 15 patients. The main weakness of the clinical reports was that they were not detailed enough, particularly regarding the localization of injuries and description of wound morphology. In seven cases, however, forensic conclusions were possible on the basis of the written clinical reports, whereas in five cases forensic reconstruction required specific follow-up reading. The additional 0.6-mm slices were easily available and with improved 3D image quality and forensic diagnostics. In conclusion, the use of clinical CT data can considerably support forensic expertise regarding reconstruction issues. Forensic follow-up reading as well as the use of additional thin slices for 3D analysis can further improve its benefit for forensic reconstruction purposes.

Gas-discharge diagnostics of text on paper

Barrier gas discharge in avalanche form has been used to study a hand-written text on paper with various ages of records. A comparison of the optical images of this text with gas-discharge patterns showed that the latter possess certain advantages. It is demonstrated that barrier discharge can be used for forensic diagnostics of hand-written paper documents with the aim of revealing additions written at various times.

Development of a Long QT-Syndrome mutation detection method

Sudden cardiac death (SCD) especially in younger adults with no previous symptoms is a challenging problem in forensic diagnostics, occurring with an incidence of about 80,000 per year in Germany. Long QT-Syndrome (LQTS) and other cardiac disorders associated with abnormality of cardiac rhythm triggered by mutations of cardiac ion channels have to consider if no cause of death is detectable during autopsy. A molecular genetic screening can help to ensure. Meanwhile twelve genes are known in which more than 700 different mutations are associated with LQTS. The three major LQTS-susceptibility genes are KCNQ1, KCNH2 and SCN5A. They are responsible for 75% of all congenital LQTS cases. We developed a rapid, sensitive and reasonable method for the simultaneously screening of the most common LQTS mutations, focused on these three genes. Using the SNaPshot ® minisequencing primer extension assay a total of 91 Single-Nucleotide Polymorphisms (SNPs) were examined in six multiplex assays. The data suggest that this technique is applicable, solid, flexible and a good alternative to complete sequencing.

Forensic use of radiometric method for determination of gases, acid–alkaline balance and fractions of haemoglobin in blood/practical significance of blood gases examination to forensic diagnostics

Forensic use of radiometric method for determination of gases, acid–alkaline balance and fractions of haemoglobin in blood/practical significance of blood gases examination to forensic diagnostics

Immunohistochemical Staining as a Potential Method for the Identification of Vaginal Epithelial Cells in Forensic Casework*

There is currently no accurate method to identify vaginal epithelial cells uniquely. This study aimed to use a cell extraction procedure compatible with routine forensic sampling methods, and to investigate the expression of cytokeratin (CK), estrogen receptor-alpha (ERalpha), and phosphodiesterase 5 (PDE5) in order to distinguish between skin, buccal, vaginal, and external penile epithelial cells. Seminal fluid samples were also examined. Epithelial cell samples were fixed in formalin, embedded in agarose, and processed using histological methods. Antigen-antibody reactions were detected using the DAKO Envision+ detection system. CK was present in all cells from all five sources confirming the origin of cells as epithelial. Both ERalpha and PDE5 positively labeled vaginal, buccal, and skin epithelial cells. Although an antigen unique to vaginal epithelial cells was not identified, we have described a cell extraction procedure for use in the immunohistochemical detection of a wide range of antigens, an approach compatible with forensic diagnostics.

2005 Lasker Awards Honor Groundbreaking Biomedical Research, Public Service

PIONEERING STEM CELL RESEARCHers, innovative geneticists, and a tireless advocate of breast cancer research and awareness are being honored this week as recipients as the 2005 Albert Lasker Medical Research Awards. Now celebrating its 60th anniversary, the Lasker Awards are the United States’ most distinguished honor for contributions to basic and clinical medical research, as well as public service on behalf of the medical research enterprise. The Lasker Award for Basic Medical Research is shared by Ernest McCulloch, MD, and James Till, PhD, of the Ontario Cancer Institute, in Toronto, Canada, for experiments that first identified a blood-forming stem cell and set the stage for current research on adult and embryonic stem cells. The Lasker Award for Clinical Medical Research is awarded to Sir Edwin Southern, FRS, of the University of Oxford, and Sir Alec Jeffreys, FRS, of the University of Leicester, both in the United Kingdom, for development of two genetic technologies, Southern hybridization and DNA fingerprinting, that together revolutionized human genetics and forensic diagnostics. The Mary Woodard Lasker Award for Public Service honors Nancy Brinker, founder and president of the Dallas, Tex.–based Susan G. Komen Breast Cancer Foundation, for creating one of the world’s most notable foundations devoted to curing breast cancer and dramatically increasing public awareness about this disease. Joseph Goldstein, MD, a past Lasker winner who serves as chairman of the international jury that selects recipients of the Lasker Awards for research, explained that thisyear’sBasic andClinicalResearchawardsrecognizedresearchers whose insights had far-reaching effects. “Occasionally scientists take special note of an observation or interpret it in a novel way,” he said. “These ‘eureka moments’ can profoundly alter the course of scientific progress. This year’s Lasker Awards honor three such achievements.” Daniel Koshland, PhD, professor emeritus at the University of California, Berkeley, and chairman of the selection committee for the Lasker Award for Public Service, explained why Nancy Brinker was chosen. “Brinker has devoted her life to fulfilling a pledge to her dying sister to raise public awareness about breast cancer, promote its early diagnosis and effective treatment, and increase medical research to achieve its eventual eradication.” The awards will be presented at a luncheon ceremony on September 23 in New York City.

Combination of DNA-Based and Conventional Methods to Detect Human Leukocyte Antigen Polymorphism and Its Use for Paternity Testing

In cases of disputed paternity, the scientific goal is to promote either the exclusion of a falsely accused man or the affiliation of the alleged father. Until now, in addition to anthropologic characteristics, the determination of genetic markers included human leukocyte antigen gene variants; erythrocyte antigens and serum proteins were used for that reason. Recombinant DNA techniques provided a new set of highly variable genetic markers based on DNA nucleotide sequence polymorphism. From the practical standpoint, the application of these techniques to paternity testing provides greater versatility than do conventional genetic marker systems. The use of methods to detect the polymorphism of human leukocyte antigen loci significantly increases the chance of validation of ambiguous results in paternity testing. The outcome of 2384 paternity cases investigated by serologic and/or DNA-based human leukocyte antigen typing was statistically analyzed. Different cases solved by DNA typing are presented involving cases with one or two accused men, exclusions and nonexclusions, and tests of the paternity of a deceased man. The results provide evidence for the advantage of the combined application of various techniques in forensic diagnostics and emphasizes the outstanding possibilities of DNA-based assays. Representative examples demonstrate the strength of combined techniques in paternity testing.

Investigations on the reliability of determiningan individual's age from the proximal femur

In the context of individual identifications the reliable determination of age is important. It has been suggested that the femur is appropriate for reliably determining age and excellent results were indeed claimed but calculated errors of estimation were often missing in the studies. In order to check the reliability and validity for forensic diagnostics, two independent investigators who were not informed of the actual age of the femur specimens evaluated x-ray views of 90 femurs according to methods described in the literature. The results of the two investigators differed by maximally 5 years in 64.4% of all cases examined; the average error of estimation amounted to 10.1-17.0 years. Only one-seventh of all cases examined could be precisely grouped into the 5-year class. Deviations of more than 15 years occurred in nearly one fourth of all cases. In particular, individuals over 50 years of age were estimated as being much younger. We must therefore conclude that the method under examination is only appropriate for rough estimations of age. A more accurate estimation within a five-year interval is only rarely possible.

Vibrational spectrum of strychnine: detection at the nanogram level using a Raman microscope

The complete vibrational spectra of strychnine is reported. Strychnine, a compound with medicinal value at the proper dosage, is also a potent toxin at certain concentration levels. Down to 5 ng of strychnine were detected from its spectrum using a microscope attached to a Raman spectrophotometer. The complete Raman and Fourier transform IR spectra were also recorded for positive identification. The prominent vibrational band wavenumbers useful as a reference source for the identification of strychnine in an emergency situation are discussed. The Raman spectra of a bulk sample and of a strychnine microcrystal are given to facilitate positive identification. The potential application of the vibrational analysis of strychnine for forensic diagnostics is discussed. Copyright © 1999 John Wiley & Sons, Ltd.