Determination of the age of wounds by histochemical and biochemical methods

Methods of enzyme histochemistry can reveal vital changes around skin wounds and burns inflicted about one hour before death. This is about 8 times earlier than was possible before, when only histological methods were used. Histochemical methods act further as a guide to estimate the approximate age of wounds, especially of those inflicted 1–16 hours before death. However, conditions like senility, cachexia and severe brain injuries may impair the local reactions and thus complicate the dating of wounds. The determination of the age of wounds becomes more reliable when several independent methods are used simultaneously. The techniques of enzyme biochemistry seem to provide an experimental basis of new methods for the distinction between ante-mortem and post-mortem wounds. Isoelectric focusing in polyacrylamide gel has revealed qualitative differences between the enzymes (arylaminopeptidases and esterases) from ante-mortem and post-mortem wounds, respectively. Autopsy studies on the applicability of enzyme biochemical methods are in progress. By contrast, biochemical histamine and serotonin determinations, as well as enzyme histochemistry, are applicable even in forensic practice. According to our autopsy studies, a distinct increase (twofold, at least, in regard to serotonin, and 1.5-fold or more, concerning histamine) in the serotonin and free histamine content, as compared to a control sample of neighbouring intact skin, indicates the ante-mortem origin of an injury. The increases in serotonin and histamine are the earliest vital reactions so far known, becoming demonstrable after a survival time of as little as some minutes.