Garazdiuk M. Time monitoring of posthumous changes of autofluorescence of liquor films for post-mortem interval estimation

Post-mortem interval estimation, improving the accuracy of its establishment in the first hour, and establishing of death causes are the most important problems of forensic medicine practice. Since posthumous changes in human body tissue are accompanied by complex complex changes in their morphological structure and biochemical composition, such processes, in addition to traditional forensic methods, allow to be estimated and evaluated by modern biophysical diagnostic methods. The aim of the study was to develop a complex of forensic medical criteria to improve the accuracy of establishing the prescription of death on a short-term time interval (1-6 hours) and the differentiation of causes of death due to cardiovascular disease and alcohol poisoning according to cytological data, spectrophotometry in ultraviolet rays, polarization correlation and fluorescence microscopy of cerebrospinal fluid of a human corpse on the basis of statistical and scale-selective analysis temporal dynamics of the spectrophotometric density of cerebrospinal fluid and coordinate distributions of polarization and fluorescence correlation maps its polycrystalline films. Materials and methods. The object of the study was native films, painted films and liquid samples of cerebrospinal fluid, taken in 140 corpses of both sexes (the main group of research) from the age of 19 to the 93 with the previously known time of death ranging from 1 to 40 hours, and 30 healthy volunteers (a comparison group). The cause of death of corpses were cardiovascular pathology. The exclusion criteria were: the presence of craniocerebral injury, central nervous system disease, suspicion of stroke. The research used the following methods: 1. spectrophotometry in the ultraviolet range of the spectrum of electromagnetic radiation in the range of wavelengths from 280 μm to 380 μm; 2. cytological study of time dynamics of posthumous change of morphology of cells of cerebrospinal fluid; 3. two-dimensional polarimetry of polycrystalline films of cerebrospinal fluid: • stokes-polarimetry in different spectral bands of optical radiation - determination of coordinate distributions of azimuth values and ellipticity of polarization; • stokes-correlometry - the definition of coordinate distributions of the values of a complex degree of mutual polarization, which characterizes the consistency of states of polarization at different points of the microscopic image; 4. stokes polarimetry of microscopic images of polycrystalline films of a cerebrospinal fluid with spatial frequency filtration; 5. stokes polarimetry of fluorescence microscopic images of polycrystalline films of cerebrospinal fluid. Results and conclusions. The dissertation provides a theoretical basis and experimentally determines set of current forensic diagnostic cytological, spectrophotometric, polarization-correlation and spectral-selective interrelations between post-mortem interval and causes of death due to cardiovascular pathology and severe alcohol intoxication with a possible lethal outcome and statistical moments of 1 - 4- th orders that characterize the time variations of the coordinate distributions of the spectral density, azimuth, ellipticity, complex degree mutual polarization and fluorescence polarization azimuth polycrystalline films of cerebrospinal fluid in postmortal period. It was established that the time dynamics of the change in the magnitude of the statistical moments of the 3rd and 4th orders, which characterize the coordinate distributions of azimuths of the laser-induced fluorescence polarization in the "green-yellow" (asymmetry from 0.68 to 1.53, an excess of 1.23 to 1.89) and "red" (asymmetry from 0.58 to 1.57; excess from 0.82 to 1.67) spectral regions ensures the precision of post-mortem interval estimation in the value of ±7,5 minutes at a time interval of 6 hours after death. Significant signs for forensic differential diagnostics of cardiovascular pathology and severe alcohol intoxication with a possible lethal outcome by the method of laser-induced fluorescence in the "red" section of the spectrum were revealed.