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Recent studies show that Langerhans cell density increases in vital lesions and ligature marks when compared with post-mortal wounds. The enzyme, iNOS, has been established as a marker for estimating time of agony and serves in the regulation of dendritic cell behaviour. It is the aim of this paper, therefore, to evaluate the expression of this enzyme by Langerhans cells and the possible consequences that may be related to the production of nitric oxide by these cells in other types of lesions, including hanging furrows. The results show a greater expression of iNOS by Langerhans cells at the level of the hanging furrow when compared with other examined groups. Apart from an increase in the expression of iNOS, a large fraction of the mast cell population in the class II MHC molecules was observed in the hanging furrow. This corroborates that interactions between mast cells and dendritic cells are critical for the differentiation of these latter cellular types. Hence, the results suggest that iNOS plays a crucial role in the forensic practice of establishing the time interval in defining the vitality in hanging marks. [ABSTRACT FROM AUTHOR]

Hanging deaths are common and characterized by their brief survival time. Macroscopic and histological exams are frequently unable to distinguish vital lesions from post-mortem lesions. This pilot study investigates the dendritic and mast cells in hanging marks to establish vitality lesions. Skin specimens were taken from vital wounds, ligature marks, and post-mortem lesions. Cryosections were stained for haematoxylin eosin, avidin, CD1a and MHC class II+ antigens and examined under light or fluorescence microscopies. Using digitized photomicrographs the images were then analysed. Differences were found in the Langerhans cells and epidermal MHC density, the vital lesions and ligature marks and the other specimens. The results may prove useful in forensic practice when neither macro nor microscopic objective evidence of vitality is available. The results could very possibly support the hypothesis that the amount of time it takes to die from hanging is less than currently believed (< 5 min). [ABSTRACT FROM AUTHOR]