Fatal craniocerebral trauma in a young child. I: Forensic documentation,model generation and geometric impact conditions

The aim of forensic biomechanics is the reconstruction of traumatic events based on the pathological findings in the victim's morphology and on the traces and shapes of the traumatizing tools. The introduction of Streifenlichttopometrie into forensic science enables 3-dimensional and proportionally accurate documentation of the victim's body and injuring agent with submillimeter precision. The advantages of this method of documentation are the possibilities of producing animated models which correspond exactly to the body's shape and injury topography, and of ascertaining the physical parameters (centers of mass, moments of inertia) of the various body parts and the geometrical impact conditions for the reconstruction of the injury dynamics. This way of proceeding thus enables more precise models than hitherto possible for kinetic and dynamic reconstruction. In the case of an infant who was fatally injured by a wooden sculpture the generation and application of computer aided 3-dimensional reconstruction models are shown.     

Immunocytochemical examination of biological traces on knife blades

In cases of penetrating stab wounds by different knives it is highly relevant to prove which knife caused which injury, especially if one of the injuries was lethal. This is possible by immunocytochemical examination of cellular material remaining on the injuring blade because some organs have organ-specific antigen determinants such as alpha-l-fetoprotein in the liver cells or cardiac troponin I in the heart muscle cells, to which antibodies can bind. Even when penetrations occur through several layers of clothing, enough cells from the injured organ remain on the blade of a knife to allow immunohistochemical examination. These cells can be collected by means of adhesive film or wiping the blade and can be stained immunocytochemically. The organ specificity of the examined proteins allows proof of their origin. The present study shows that immunocytochemical alpha-l-fetoprotein and cardiac troponin I staining of the cells remaining on a knife blade enables proof of whether the knife blade injured the heart or the liver, or both.     

Immunohistochemical proof of amelogenin in teeth--a contribution to the evaluation of the age in the identification of unknown corpses

When a corpse is found that cannot be identified, one of the forensic tasks is to determine how old the person was when she or he died. To solve this frequently asked question in forensic practice, the enamel protein amelogenin was marked immunohistochemically in 249 extracted teeth. Amelogenin is already produced during prenatal development and is gradually used up throughout life into old age. Hence, the demonstrability decreases with age. The extent of the labelling can be quantified by measuring the mean optical density (MOD). While it is not possible to determine the age on the basis of the mean optical density measurements alone, logistic regression of the MOD together with dichotomisation of the teeth according to age allows statements as to whether the person was younger or older than 30 years.     

Delimitation of the time of death by immunohistochemical detection of insulin in pancreatic beta-cells

To improve the possibilities to delimitate the time of death after longer laytime, it was examined if this is possible by immunohistochemical insulin detection. The results show that in our examination material, the pancreatic beta-cells of up to 12-day-old corpses produce a positive immunoreaction towards insulin in all cases, whereas none of the corpses older than 30 days show such a reaction. This means that in case of a negative immunoreaction, the time of death can be assumed to lie more than 12 days before the autopsy. The fact that a negative immunoreaction occurs consistently after 30 days leads to the conclusion that when insulin has been stained in a specimen, the death of the respective person must lie a maximum of 29 days earlier, whereby these time-limits may change in considerably different surrounding conditions.     

Visualization of biological traces on evidence by ninhydrin

Because of possible contamination of samples with PCR inhibitors and to avoid the typing of mixed profiles the source material for forensic DNA investigations should be collected as directly and securely as possible from the evidence. This approach requires a detectability of the source material which is often not given. The procedure introduced here using selected cases enables visualization of DNA-containing materials on evidence and hence controlled analysis. For this purpose the specimen is treated with ninhydrin. A following dye reaction verifies the presence of biological material, which possibly contains DNA. An impact on subsequent STR-analysis was not observed.     

Pharmacokinetic features in forensic medicine

As a rule, the concentration curves of substances in various body volumes, in particular in plasma and blood volume, can be reproduced by a number of exponentional functions. A compartment system can be isomorphically assigned to such a representation in which a mass exchange takes place between the constituent volumes. In forensic medicine (toxicology), the "central compartment model" is used in which an exchange of substances between the blood space (central compartment) and the peripheral spaces (peripheral compartments) takes place. Characteristic parameters of the compartment models are their volumes and the intercompartmental mass flows or their rate constants. They can be determined from the mathematical representations of the concentration curves. It is possible to obtain knowledge on the properties (e.g. permeability) of the convectional/diffusional transcapillary transport on the basis of these parameters.