RNA and DNA synthesis of epidermal basal cells after wounding. Comparison of vital and postmortem investigations

Review of the current and potential use of biological and molecular methods for the estimation of the postmortem interval in animals and humans

We provide here an overview of the state of applied techniques in the estimation of the early period of the postmortem interval (PMI). The biological methods included consist of body cooling, CSF potassium, body cooling combined with CSF potassium, and tissue autolysis. For each method, we present its application in human and veterinary medicine and provide current methodology, strengths, and weaknesses, as well as target areas for improvement. We examine current and future molecular methods as they pertain to DNA and primarily to messenger RNA degradation for the estimation of the PMI, as well as the use of RNA in aging wounds, aging blood stains, and the identification of body fluids. Various types of RNA have different lengths, structures, and functions in cells. These differences in RNAs determine various intrinsic properties, such as their half-lives in cells, and, hence, their decay rate as well as their unique use for specific forensic tests. Future applications and refinements of RNA-based techniques provide opportunities for the use of molecular methods in the estimation of PMI and other general forensic applications.

Omics era in forensic medicine: towards a new age

Background/aim

Forensic medicine and sciences is a multidisciplinary branch of science, which frequently benefit from novel technologies. State of the art omics technologies have begun to be performed in forensic medicine and sciences, particularly in postmortem interval, intoxication, drugs of abuse, diagnosis of diseases and cause of death. This review aims to discuss the role and use of great omics (metabolomics, proteomics, genomics and transcriptomics) in forensic sciences, in detail.

Materials and methods

A detailed review of related literature was performed, and studies were subdivided as per the type of omics.

Results and conclusion

Omics seems as a revolutionary step in forensic science and sure carries it towards a new age. The number of forensic studies utilizing omics steadily increases in last years. Omics strategies should be used together in order to gather more accurate and certain data. Additional studies need to be performed to incorporate omics into routine forensic methodology.

Forensic molecular pathology: its impacts on routine work, education and training

The major role of forensic pathology is the investigation of human death in relevance to social risk management to determine the cause and process of death, especially in violent and unexpected sudden deaths, which involve social and medicolegal issues of ultimate, personal and public concerns. In addition to the identification of victims and biological materials, forensic molecular pathology contributes to general explanation of the human death process and assessment of individual death on the basis of biological molecular evidence, visualizing dynamic functional changes involved in the dying process that cannot be detected by morphology (pathophysiological or molecular biological vital reactions); the genetic background (genomics), dynamics of gene expression (up-/down-regulation: transcriptomics) and vital phenomena, involving activated biological mediators and degenerative products (proteomics) as well as metabolic deterioration (metabolomics), are detected by DNA analysis, relative quantification of mRNA transcripts using real-time reverse transcription-PCR (RT-PCR), and immunohisto-/immunocytochemistry combined with biochemistry, respectively. Thus, forensic molecular pathology involves the application of omic medical sciences to investigate the genetic basis, and cause and process of death at the biological molecular level in the context of forensic pathology, that is, 'advanced molecular autopsy'. These procedures can be incorporated into routine death investigations as well as guidance, education and training programs in forensic pathology for 'dynamic assessment of the cause and process of death' on the basis of autopsy and laboratory data. Postmortem human data can also contribute to understanding patients' critical conditions in clinical management.

Vitality and time course of wounds

The term "wound" describes the morphologic-functional disruption of the continuity of a tissue structure. A wound can be inflicted during life--when the cardiovascular and respiratory system is still intact--or after death, i.e. after cardiac and respiratory arrest. Traumatization during life triggers vital reactions that do not occur in postmortem wounds. Three types of vital reactions in wound healing can be distinguished: Reactions of the scavenger type, which are almost exclusively mediated by blood cells. Reactions by complex signal transduction pathways, which involves cascade-like release of chemokines, cytokines and adhesion molecules and may influence type 1 and type 3 reactions. Reactions of the scarring type, which involve the final repair of the damaged tissue and are carried out primarily by cells residing at the wound edges, i.e. partly concerning mesenchymal cells and partly tissue-specific cells dependent on the involved organ system. The three different types of reaction follow roughly parallel temporal courses that include cascade-like interactions among themselves. Whereas demonstration of a vital reaction suffices to differentiate an intravital wound from a postmortem wound, the vital reactions themselves follow strictly temporal courses. The regular time-dependent occurrence of each phenomenon allows--in limits--a reliable temporal classification of wound healing. A review will be given especially demonstrating the actual German scientific research in vitality and in skin wound timing as well as in timing of mechanical injury of the brain.

Forensic wound examination

Wound examination is of prime importance in forensic pathology, and it is desirable to establish a wound examination system in order to evaluate and record the nature of wound more accurately and objectively. Modern diagnostic techniques and devices as well as advanced cell-biological methods should be introduced as the means for this aim. For example, radiological, endoscopic or magnetic resonance imaging (MRI) examination have been used in addition to examination with the naked eye. In our department, a binocular surgical operating microscope is routinely employed at forensic autopsy, which is useful for elucidating the nature of wound in more detail. It is also necessary to determine whether a wound has vitality, and, if antemortem, how long before death the wound has been sustained. For the determination of wound age including vitality, various biological factors such as cytokines and extracellular matrix components involved in wound healing have been examined by histopathological methods. Our studies have shown that interleukin (IL)-1alpha, IL-1 b, IL-6, IL-10 and tumor necrosis factor-alpha are possibly useful markers for wound age determination as well as cell-biological indicators of vitality. Furthermore, molecular biological techniques have been intended to be applied to wound examination; our experimental study has shown that even mRNA of cytokines mentioned above can be histologically detected by reverse transcriptase-polymerase chain reaction or in situ hybridization. A trial of forensic wound examination from macroscopic to molecular level is discussed.