ALTERAZIONI MICROSCOPICHE DELLA DECOMPOSIZIONE:IMPLICAZIONI PER LA MEDICINA LEGALE

One of the most crucial issues in forensic pathology is the interpretation of decompositional and taphonomical alterations. Decomposition processes encompass every kind of modification which may take place in corpses after death; literature and common experience agree on the specific and individual characteristics of such processes which are dependant on several environmental variables, and only few of them are well known and predictable. The analysis of transformative processes therefore is relevant in order to obtain information concerning the relationship between the environmental characteristics and the corpses. To investigate the process of decomposition we performed experiment on animal corpes to verify macroscopic and microscopic changes of corpses within different environments. In particular we analyzed the decomposition processes of 16 pig carcasses (as surrogates of human cadavers) placed in the open air, under the water, inside a plastic bag, inside the concrete and buried. The pig carcass placed in the open air had been previously burned on a wood pyre. The macroscopic and microscopic information obtained from experimental studies have been completed by studying tissue samples collected from human corpses in different states of putrefaction. The second part of the study is based on the diagnosis of the vitality of the wounds, to identifying the histological features useful to differentiate an intravital wound from a postmortem one. Macroscopic haemorrhagic infiltration of the fresh skin can be, in some cases, sufficient to reveal the vitality of the wound but in many cases histological, histochemical, ultrastructural and biochemical analyses have been proposed. The differential diagnosis between vital and post-mortem bone injuries may be more difficult both during macroscopic and microscopic examination: also in these cases histological, histochemical, biochemical and ultrastructural analyses may be useful. The aim of this study was to investigate histological signs of the vitality of soft tissue and bone lesions in an advanced state of decomposition using a monoclonal anti-human Glycophorine A antibody to demonstrate the presence and the distribution of blood cells in the tissues. Moreover we tested the utility of Luminol, a chemical reagent routinely utilized by the Scientific Police to reveal the trace of blood in the scene of crime, to detect the presence of red blood cells in histological samples of wounds. Finally, we used the SEM-EDX (scanning electron microscopy coupled with energy dispersive x-ray analysis) to detect the gunshot residues to identify bone gunshot wounds. This technique demonstrated the GSR on the wounds also when the histologic analyses failed to identify them.