Validation of short tandem repeats (STRs) for forensic usage: performance testing of fluorescent multiplex STR systems and analysis of authentic and simulated forensic samples

The amplification and typing conditions for the 13 core CODIS loci and their forensic applicability were evaluated. These loci are CSF1PO, FGA, TH01, TPOX, vWA, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, and D21S11. Results were obtained using the multiplex STR systems AmpFlSTR Profiler Plus and AmpFlSTR COfiler (Applied Biosystems, Foster City, CA), GenePrint PowerPlex (Promega Corporation, Madison, WI), and subsets of these kits. For detection of fluorescently labeled amplified products, the ABI Prism 310 Genetic Analyzer, the ABI Prism 377 DNA Sequencer, the FMBIO II Fluorescent Imaging Device, and the Fluorlmager were utilized. The following studies were conducted: (a) evaluation of PCR parameter ranges required for adequate performance in multiplex amplification of STR loci, (b) determination of the sensitivity of detection of the systems, (c) characterization of non-allelic PCR products, (d) evaluation of heterozygous peak intensities, (e) determination of the relative level of stutter per locus, (f) determination of stochastic PCR thresholds, (g) analysis of previously typed case samples, environmentally insulted samples, and body fluid samples deposited on various substrates, and (h) detection of components of mixed DNA samples. The data demonstrate that the commercially available multiplex kits can be used to amplify and type STR loci successfully from DNA derived from human biological specimens. There was no evidence of false positive or false negative results and no substantial evidence of preferential amplification within a locus. Although at times general balance among loci labeled with the same fluorophore was not observed, the results obtained were still valid and robust. Suggested criteria are provided for determining whether a sample is derived from a single source or from more than one contributor. These criteria entail the following: (a) the number of peaks at a locus, (b) the relative height of stutter products, and (c) peak height ratios. Stochastic threshold levels and the efficiency of non-templated nucleotide addition should be considered when evaluating the presence of mixtures or low quantity DNA samples. Guidelines, not standards, for interpretation should be developed to interpret STR profiles in cases, because there will be instances in which the standards may not apply. These instances include (a) a primer binding site variant for one allele at a given locus, (b) unusually high stutter product, (c) gene duplication, and (d) translocation.     

Entrapment in small, enclosed spaces: a case report and points to consider regarding the mechanism of death

The mechanism of death due to confinement in an enclosed space is usually ascribed to asphyxia from oxygen deprivation. We report the case of the decomposed remains of a 23-year-old man discovered in an unused industrial size refrigerator in which the mechanism of death is heatstroke. The investigation of the death indicates the subject most likely voluntarily entered the refrigerator and for unknown reasons, closed the door. Injuries identified at autopsy and damage to the inside of the structure indicate he struggled to exit the cabinet. The autopsy shows no significant natural disease processes and toxicology studies were negative. The diagnosis of heat stroke typically rests on the evaluation of multiple features, including the age and size of the decedent, the ambient temperature, the medical history of the decedent, whole body hydration, body fat content, alcohol and drug use, medication history, general physical condition, and many other factors. The diagnosis of heatstroke due to confinement in an enclosed container requires evaluation of the heat stress of the container, the heat strain experienced by the individual, autopsy findings suggesting signs of a struggle to exit the container, and other factors. In all such cases, a careful death investigation with correlation of autopsy findings is required to accurately determine the mechanism and cause of death. We suggest that for all such deaths, physiological and environmental factors promoting hyperthermia and heatstroke be considered as a possible mechanism of death, along with those associated with the more obvious danger of asphyxiation.     

Microscopic characteristics of hacking trauma

The purpose of this study was to determine if it is possible to associate machetes, axes, and cleavers with the microscopic parallel striations they leave on the cut surfaces of the bone. Hacking trauma was experimentally inflicted on pig bones using machetes, axes, and cleavers. Negative impressions of both the cut surfaces of the bone and the weapon blades were analyzed using scanning electron microscopy. The results of this investigation indicate that it is possible to correlate a class of hacking weapons to trauma inflicted on bone by these weapons.     

Determination of heavy metals in some human organs, tissue, and fluids under normal conditions

A table has been created, presenting normal levels of heavy metals (Hg, Cd, Cr, Cu, Fe, Mn, Pb, Ni, Zn, Sn, Tl, Ag) in human biological media. In contrast to other handbooks, the authors use the normal values derived on the basis of their own investigations at the spectral laboratory of Bureau of Forensic Medical Expert Evaluations, Public Health Committee of Moscow and published reports. Comparative analysis was carried out for each element in human organs, tissues, and urine, which will facilitate expert work. Every laboratory engaged in expert evaluations and analysis in cases with suspected poisoning with heavy metal salts is to have reference values of these elements' concentrations in human organs and tissues obtained in this very laboratory on available equipment with consideration for specific features of its biogeochemical region.     

Hypophyseal damage in persons with cerebrocranial injuries and who died in the hospital

The pituitary was examined in patients with craniocerebral injuries who died in hospital in various periods after treatment. Control group consisted of victims died at the site of accident. The results indicate the significance of examining the pituitary in craniocerebral injuries for the diagnosis of thanatogenesis, particularly in patients died in hospital. Causes of traumatic changes in the organ were determined, highly incident in the practice of forensic medical experts: directly during injury, as a result of skull bone fractures; during development of dislocation syndrome and in disorders of blood and lymph circulation in the brain matter; resultant from augmenting traumatic edema of the brain.     

Clinico-morphological parameters of heroin abuse and pathology connected with it

Morphological manifestations of narcomania in heroin users are described. Diseases associated with heroin narcomania and causes of death of heroin users are presented. Morphological manifestations at the site of injections and inflammatory reactions in parenchymatous organs are characterized. The authors pay special attention to the productive inflammation which can serve as one of the signs that confirm narcomania in cases with parenteral injections of crude heroin. The authors refer the granulomas to toxic allergic form of granulomatous hypersensitive inflammation.     

Profenofos metabolites in human poisoning

Profenofos and its metabolites were determined in a case of fatal poisoning. Little profenofos and large amounts of metabolites were detected by gas chromatography/flame photometric detection in the acid extracts of blood and urine after methylation with diazomethane. Four major metabolites containing phosphorus were identified with the synthesized metabolites, namely, despropylated profenofos, desethylated profenofos and des-S-propylated profenofos, respectively. 4-Bromo-2-chlorophenol (BCP), an aryl moiety of profenofos, was also determined in blood and urine with high performance liquid chromatograph (HPLC) as free or conjugated metabolites.     

Cranio-facial morphanalysis: a new method for enhancing reliability while identifying skulls by photo superimposition

Skull-photograph superimposition continues to be the most prevalent method employed for identifying a skull recovered in a criminal case as that belonging to a putative victim whose face photograph is available. The reliability of identification achieved has been shown to be 91%, indicating the possibility of a skull mismatching with a face photograph belonging to a person other than the actual deceased. This lack of reliability dampens the confidence of the expert and in turn confounds the mind of the judge. It has been shown that the variations in the shape of the facial organs are influenced by the corresponding variations in the skeletal elements of the facial skull. "Cranio-facial morphanalysis", a new anthroposcopic method proposed here for evaluating the shape correlations between a skull and a face photograph, when applied conjointly with skull-photograph superimposition is shown to increase the reliability in forensic skull identification.