THE COMPARATIVE ANALYSIS OF DIFFERENT TECHNIQUES OF LASER POLARIMETRY FOR DETERMINATION OF TIME OF DEATH IN THE STUDY OF POLYCRYSTALLINE FILMS OF CEREBROSPINAL FLUID.

The estimation of death coming prescription (DCP) is one of the most important issues that confronts a medical examiner during the corpse examination right at the scene of death. The most promising biological object for the DCP estimation is cerebrospinal fluid. Aim - to compare the effectiveness of methods being used: stokes-polarimetry, stokes-colorimetry, autofluorescence polarimetry in order to improve the accuracy of DCP for the long - and short-term time intervals. The object of the study - cerebrospinal fluid from 75 cadavers (study group) and 20 live individuals (control group). Methods used: stokes polarimetry, stokes-colorimetry, autofluorescence polarimetry. When analyzing the image of the biological sample within the statistical analysis using the stokes polarimetry it is possible to obtain some quantitative characteristics about the amount of the statistical moments of the 1st - 4th orders, which can be used to find the relationship between them and the DCP. However, the coordinate and morphological structure of biological samples are ignored when using this approach. A correlation method in this context is more functional and sensitive. Due to this a higher accuracy of DCP is achieved in a short period. The analysis revealed that the spatial-frequency filtration of polarization-inhomogeneous images of polycrystal films of cerebrospinal fluid improves the time monitoring sensitivity of biochemical changes in optically active molecular compounds. Speaking about fluorescence microscopy - it carries the information about the concentration of molecular complexes of proteins, NADH, flavins, porphyrins, etc. As in the postmortem period the changes in the cerebrospinal fluid begin with the changes in the concentration of biochemical compounds, and crystalline changes are secondary, this method is the most effective for diagnosing the death coming prescription in the first 8 hours. The fluorescent methods of laser polarimetric are precise at a short interval of DCP estimation, and the polarization ones allow us to estimate this parameter at the long-term time intervals, though with less accuracy.