Postmortal Interval Research Articles

Use of cadaveric stem cells: analysis of literature

Determination of Post Mortem Interval (PMI) has always been based on empirical analysis of microdata not always endowed with sufficient reliability. Due to its significancy in medico-legal issues, PMI estimation needs to be assessed by applying new and more reliable methods and/or biomarkers. Considering the growing interest and use of stem cells taken from cadaveric tissues and the success in their isolation from death donors, with the maintenance of vitality and regenerative capacity, we evaluated the Literature “state of the art” on this topic to understand if those stem cells could also be used for thanatochrologic estimation. The results obtained from Literature analysis show the possibility of using these cells as a marker for the post-mortal interval. In particular Mesenchymal Stem cells, isolated from adipose and muscular tissues, can be used to evaluate their regenerative capacity over time according to the PMI.

Modern ideas about the stages of decomposition and the possibilities of forensic reconstruction of the conditions of the postmortem period

The decomposition of a corpse is a long process in time and is one of the irreversible, as it is due to the natural need for the natural recycling of nutrients in dead organic matter (dead bodies of humans and animals). The duration of decomposition varies within very wide boundaries: from several months to several hundred and thousands of years. The article conducted an analytical review of works on the processes occurring in the dead body, the staging of decomposition, and the possibilities of forensic medical reconstruction of the conditions of the postmortem period, including the establishment of the duration of the post-mortal interval. A modern approach to the consideration of postmortem changes is presented, indicating that establishing the conformity of the pathomorphology of the decomposition of corpse tissues and its underlying abiotic and biotic factors can be a justification for its actual stages. However, the degradation characteristics of dead bodies depend on a number of factors acting together on the corpse and often catalytically or inhibitively acting on each other. All these changes, with the possibility of their comprehensive analysis (taking into account numerous factors affecting their dynamics), play a crucial role in establishing the duration of the postmortal interval.

Time of immersion of bodies found in water in Northern Patagonia Argentina

IntroductionThe estimation of the immersion time of bodies recovered from the water, through the evaluation of the cadaveric changes, allows inferring the time that they have remained in the water regardless of the cause of death. In the present study, the Daily Accumulation of Degrees (ADG) method is analyzed for the calculation of the immersion interval in bodies recovered from the water in 36 bodies with a known interval of permanence in the water. Material and methodsA total of 161 bodies were recovered from the water between 2007 and 2022, in 41 cases there was data to be analyzed by the ADG method and 36 were suitable for analysis of the method when confronted with the known intervals of immersion of the bodies. ResultsThe comparison of calculation by Daily Accumulation of Degrees versus Known Immersion Interval, of the sample of 36 cases, showed that the difference in days obtained is statistically significant (p 0.48 > 0.005). In 16 cases (44.4%) there was an underestimation by the Daily Accumulation of Degrees method with respect to the time spent in the known water that differed by an average of 40%, and in 18 cases (50%) an overestimation of 41%. Based on the observation of the cadaveric changes, the month of the year and the water temperature, a table was made to estimate the Postmortal Interval of Immersion for watercourses in Northern Patagonia. ConclusionThe method of Daily Accumulation of Degrees in bodies recovered from the water to estimate the immersion interval may give a false perception of accuracy due to the complexity of integrating all the changing factors that affect human decomposition in aquatic environments.

Data de inmersión en cuerpos recuperados del agua en el norte de la Patagonia Argentina

IntroductionThe estimation of the immersion time of bodies recovered from the water, through the evaluation of the cadaveric changes, allows inferring the time that they have remained in the water regardless of the cause of death. In the present study, the Daily Accumulation of Degrees (ADG) method is analyzed for the calculation of the immersion interval in bodies recovered from the water in 36 bodies with a known interval of permanence in the water. Material and methodsA total of 161 bodies were recovered from the water between 2007 and 2022, in 41 cases there was data to be analyzed by the ADG method and 36 were suitable for analysis of the method when confronted with the known intervals of immersion of the bodies. ResultsThe comparison of calculation by Daily Accumulation of Degrees versus Known Immersion Interval, of the sample of 36 cases, showed that the difference in days obtained is statistically significant (p= 0.48 > 0.005). In 16 cases (44.4%) there was an underestimation by the Daily Accumulation of Degrees method with respect to the time spent in the known water that differed by an average of 40%, and in 18 cases (50%) an overestimation of 41%. Based on the observation of the cadaveric changes, the month of the year and the water temperature, a table was made to estimate the Postmortal Interval of Immersion for watercourses in Northern Patagonia. ConclusionThe method of Daily Accumulation of Degrees in bodies recovered from the water to estimate the immersion interval may give a false perception of accuracy due to the complexity of integrating all the changing factors that affect human decomposition in aquatic environments.

The Role of DNA Degradation in the Estimation of Post-Mortem Interval: A Systematic Review of the Current Literature.

The determination of the post-mortal interval (PMI) is an extremely discussed topic in the literature and of deep forensic interest, for which various types of methods have been proposed. The aim of the manuscript is to provide a review of the studies on the post-mortem DNA degradation used for estimating PMI. This review has been performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the PRISMA Guidelines. Several analytical techniques have been proposed to analyse the post-mortem DNA degradation in order to use it to estimate the PMI. Studies focused mainly on animal models and on particular tissues. The results have been mixed: while on the one hand literature data in this field have confirmed that in the post-mortem several degradation processes involve nucleic acids, on the other hand some fundamental aspects are still little explored: the influence of ante and post-mortem factors on DNA degradation, the feasibility and applicability of a multiparametric mathematical model that takes into account DNA degradation and the definition of one or more target organs in order to standardize the results on human cases under standard conditions.

Ultrastructural changes of renal epithelial cells during postmortem autolysis: Experimental work

Determination of schedule and certain predictable regularities of ultrastructural changes of proximal tubules epithel of kidney during post mortal interval would be very useful in forensic medicine when it is needed to determine the exact time of death. In this research there were 52 experimental animals, laboratory rats "Wistar" type, which had been killed by choking. Four animals were selected to be a control group right after death, and 48 rats were divided into three equal groups: The rats were then fended on different temperatures: 8-10 degrees C, 18-20 degrees C, 28-30 degress C, respectively. In each and every group the rats were divided into four groups based on time interval after death: 1, 2, 4 and 6 hours. There were four rats in each of those four subgroups. Preparations were analyzed and photographed using transmission electronic microscope. It was found that pace of ultrastructure changes of proximal tubules epitel the cells of kidney was directly dependable on the duration of autolysis and temperatures that the body was stored at. First changes on nucleus, which are separation of external and internal membranes, occurred during the fourth hour of autolysis. Decomposition of external membrane occurred also during fourth hour on temperatures of 8-10 degress C and 18-20 degrees C. When the body was stored at 30 degrees C lysised decomposition of both membranes of nucleus and loss of natural nucleus shape were noticeable even during the first hour of autolysis. During the sixth hour nucleus membranes were almost lysised around the perimeter and that led to "leaking" of chromatin in sarkoplasm. Mitochondria kept their normal shape six hours after death when the body was stored on 8-10 degrees C and 18-20 degrees C and lysis and fragmentation of cristae were noticeable from the first hour of autolysis. Mitochondria lost their natural shape and inner composition during the first hour when the body was stored at 30 degrees C. So, after the fourth hour only balloon like and lightened remaining of mitochondria and fragmented pieces of their cristae were noticeable. All of the predictable changes found in morphological changes on subcell level of kidney tissue can be useful to determine very precisely the time of death. They can be also used to determine vital value of tissue and organs.

Analysing of 228Th, 232Th, 228Ra in human bone tissues for the purpose of determining the post mortal interval

Bone tissues of thirteen deceased persons were analyzed to determine the activity concentration of the radionuclides 228Ra, 228Th, 232Th and 230Th. The activity ratios enable to assess the post-mortem-interval (PMI). The samples were prepared for analysis by incinerating and pulverizing. 228Ra was directly detected by γ-spectrometry. 228Th, 230Th, 232Th were detected by α-spectrometry after radiochemical purification and electro-deposition. It is shown that the method is principally suited to determine the PMI. A minimum of 300 g (wet weight) of human bone tissue is required for the analysis. Counting times are in the range of one to two weeks.

Improved estimation of postmortem interval based on differential behaviour of vitreous potassium and hypoxantine in death by hanging

Many formulae are available to estimate the relation between the potassium ([K +]) and hypoxantine ([Hx]) concentration in the vitreous humour and the postmortem interval (PMI). Typically these have been based on a correlation test and linear regression using the postmortal interval as the independent variable and [K +] or [Hx] as the dependent variable in order to estimate the confidence interval. However, a recent study has shown that a more precise measurement of PMI can be obtained if [K +] is used as the independent variable. The regression lines obtained from the most recent deceased subjects with forensic relevance received for autopsy in the Institute of Legal Medicine are [K +]=5.589+0.174PMI and [Hx]=26.459+3.017PMI, by changing the variables, we obtain PMI=3.967[K +]−19.186 ( R 2=0.688, P<0.001) and PMI=0.172[Hx]+0.170 ( R 2=0.518, P<0.001). In this paper we propose the cause of death as an extra factor which modifies the relationship and gives even greater precision in estimating PMI. In cases of death by hanging the results are considerably improved with [K +]=5.224+0.225PMI and [Hx]=15.161+4.957PMI, respectively, and consequently, PMI=3.631[K +]−17.334 ( R 2=0.818, P<0.001) and PMI=0.153[Hx]−0.368 ( R 2=0.757, P<0.001): the slope is less and the precision is obviously enhanced.

Cytokinetics of epidermic cells in skin from human cadavers. I. Dependency on the postmortal interval.

Punch biopsies taken from the extensor side of the thigh of 35 human cadavers were incubated in vitro with radioactively labeled thymidine (3H-thymidine = 3H-TdR, 14C-thymidine = 14C-TdR) to determine whether a relationship exists between changes in the proliferative activity of the skin and the postmortal interval after irreversible cardiac arrest. The cadavers were stored at 4 degrees C. Cadavers with indeterminable time of death or presence of intoxication, drug therapy with cytostatic agents, or a skin disease were excluded from the study. Single, double, or multiple biopsies were performed on the same cadaver; single labeling with 3H-TdR was done in all cases; double labeling with 3H-TdR and 14C-TdR in selected cases. No relevant changes in the labeling index (mean, 2.39 +/- 1.03%) were demonstrable within the examined postmortal interval of 77.75 h. The DNA synthesis time (ts) was, on the average, 4.75 +/- 1.44 h; a certain relationship to the postmortal interval existed since ts declined with increasing storage time. The potential doubling time (tpot) decreased accordingly, beginning with 181.7 h (mean storage time, 29.9 h) and ending with 137.7 h (mean storage time, 41.7 h). No statistically relevant differences, however, were established at the 1% level. Whereas both labeling index and tpot during the early postmortal interval are comparable with observations in live humans, ts was relatively short as compared to that for the epidermis of live humans.

Supravital electrical excitability of muscles

A new method of postmortem electrical stimulation of muscles, measuring the force of the reaction against time, is presented. Preliminary investigations have yielded the following results: The maximum force of reaction in response to a definitive stimulation, measured by a sensitive force transducer, decreases in proportion to the post mortem interval. Using this method, the mechanical reactions of muscles by electrical stimulation can be demonstrated over a much longer postmortem period as these movements are visible. The duration of postmortem reaction of different muscles seems to be much more uniform than was previously assumed. Occasionally, reactions of the M. orbicularis oculi can be seen for the longest time. The basal muscular tonus changes relative to time. The time course of a single force reaction also changes relative to the postmortal interval: the reaction becomes slower. It has been theoretically established that measurement of influencing factors such as temperature and pH in the tested muscle will enable the time of death to be more precisely estimated.

Significance of the putrefactive bacterium Clostridium sordellii for the determination of age of the cadaver

The method of determining postmortal interval by means of the content of ABU, GABA and GLU in putrefied postmortem brain is based on the speed of spreading, the metabolism and the growth of certain clostridia. The experiments have shown that the fecal bacteria can reach the brain in a few days. The significance of this temperature-dependent invasion ability of the bacteria for the determination of the age of the corpse is discussed.

Enzyme activity of isolated leukocyte populations. II. Cytochemical and zymographic studies of cadaver blood

Blood was taken from the femoral vein of 17 autopsied cadavers with different diagnoses and postmortal intervals (10-120 h). The granulocytes and lymphocytes were isolated with routine methods. The cell suspensions were subject to morphologic, enzyme-cytochemical (naphthol AS-D chloroacetate esterase) and electrophoretic (PGM1, PGM3, GOTM, PEPA, MEM, FUCA) investigations. The following results were obtained: Erythrocyte-free cell suspensions are only found during short postmortal intervals; Isolation of pure lymphocytes from cadaver blood using the described method is only possible very early in the postmortal interval (within 10 h); The isolated granulocytes contain an impressively high percentage of eosinophilic granulocytes; The percentage of naphthol AS-D-chloroacetate esterase-positive granulocytes is considerably lower in stored, conserved blood than in blood smears; Identification of the above mentioned enzymes from isolated granulocytes from all cadavers is possible by electrophoresis.

Enzyme alterations in brain tissue during the early postmortal interval with reference to the histomorphology: review of the literature.

The state of research on enzyme alterations in brain tissue during the early postmortal interval is surveyed with special reference to the histomorphology; the questions currently discussed in the literature are given special consideration. The type of alterations appearing during the postmortal interval and their dependency on the length of the interval are described so that practically applicable conclusions may be drawn. The findings on enzyme alterations presented in the literature (enzymes of the oxidative metabolism, transmitter, enzymes) are compiled in tables. It could be shown that important structural alterations ascertainable with light microscopy and quantitative alterations in enzyme activity ascertainable with biochemical methods do not usually occur during a 6- to 8-h postmortal interval. Qualitative investigations (i.e., histoenzymatic studies) with longer postmortal intervals and with positive findings are applicable.

Postmortal diffusion of plasma albumin in rat brain.

After i.v. injection of Evans blue solution (EB), the postmortal diffusion of plasma albumin and its relationship to the postmortal interval (0 to 48 h) were studied in rat brain. A decrease in intravascular plasma albumin with increasing evidence of the same fraction in relation to the length of the postmortal interval was observed via diffuse EB fluorescence in the perivascular, periventricular, and subpial neuropil. Stained nerve cells and single endothelial cells were found grouped around individual vessels, particularly in the region of the basis encephali. The EB-fluorescent cells proved to be hyperchromatic when subsequently stained with cresyl violet; the nerve cells therefore were considered dark neurons. EB-fluorescent dark neurons were also found around the lesion in experiments involving postmortal traumatic damage of cerebral tissue. Since all EB-fluorescent nerve cells proved to the dark neurons, but not all dark neurons exhibited EB fluorescence, it was concluded that dark neurons possess a capacity for intensifying the absorption of plasma albumin. No fluorescence was demonstrated in control studies of cerebral tissue in which EB had not been injected.