Determination Of Postmortem Interval Research Articles

Evaluation of the effect of clonazepam and its metabolites on the life cycle of Megaselia scalaris (Loew) (Diptera: Phoridae)

Fly colonization patterns and development are crucial in estimating the post-mortem interval (PMI) of decomposing corpses. Understanding the potential effects of xenobiotics on species development in cadaveric entomofauna is essential for accurate PMI estimation, given their presence in decomposing bodies. Benzodiazepines, commonly prescribed for their anxiolytic, hypnotic, and muscle relaxant effects, are of forensic interest due to their potential for abuse, dependence, intoxication, and overdose-related deaths. This study aimed to explore the effect of clonazepam and its metabolites on Megaselia scalaris, a species commonly used to estimate PMI, the alteration of which could impact the accuracy of said estimation. The S9 biotransformation fraction, an in vitro model consisting of an array of metabolic enzymes, was used to generate phase I and II metabolites for evaluating their effect on M. scalaris development, representing an innovative approach to this type of study. Megaselia scalaris larvae were reared in synthetic growth media under controlled conditions. The study compared different groups: control, clonazepam, and clonazepam with S9 fraction. Larvae were measured daily to determine growth rate, and clonazepam concentrations were analyzed using HPLC-DAD. Results showed that larvae grown in media containing clonazepam or clonazepam with S9 fraction developed faster than control larvae, reaching their pupal stage earlier. Growth rates were also altered in treated groups. In conclusion, the presence of clonazepam and its metabolites accelerated the life cycle of M. scalaris, potentially impacting the accuracy of PMI estimation. These findings underscore the importance of considering xenobiotics in forensic entomological studies for precise post-mortem interval determination.

Evaluation of the effect of clonazepam and its metabolites on the life cycle of Megaselia scalaris (Loew) (Diptera: Phoridae)

Fly colonization patterns and development are crucial in estimating the post-mortem interval (PMI) of decomposing corpses. Understanding the potential effects of xenobiotics on species development in cadaveric entomofauna is essential for accurate PMI estimation, given their presence in decomposing bodies. Benzodiazepines, commonly prescribed for their anxiolytic, hypnotic, and muscle relaxant effects, are of forensic interest due to their potential for abuse, dependence, intoxication, and overdose-related deaths. This study aimed to explore the effect of clonazepam and its metabolites on Megaselia scalaris, a species commonly used to estimate PMI, the alteration of which could impact the accuracy of said estimation. The S9 biotransformation fraction, an in vitro model consisting of an array of metabolic enzymes, was used to generate phase I and II metabolites for evaluating their effect on M. scalaris development, representing an innovative approach to this type of study. Megaselia scalaris larvae were reared in synthetic growth media under controlled conditions. The study compared different groups: control, clonazepam, and clonazepam with S9 fraction. Larvae were measured daily to determine growth rate, and clonazepam concentrations were analyzed using HPLC-DAD. Results showed that larvae grown in media containing clonazepam or clonazepam with S9 fraction developed faster than control larvae, reaching their pupal stage earlier. Growth rates were also altered in treated groups. In conclusion, the presence of clonazepam and its metabolites accelerated the life cycle of M. scalaris, potentially impacting the accuracy of PMI estimation. These findings underscore the importance of considering xenobiotics in forensic entomological studies for precise post-mortem interval determination.

The micro CT evaluation of crown and root pulp volume versus dentin thickness in teeth in postmortem interval (PMI).

Determining the postmortem interval (PMI) is one of the main study subjects of forensic sciences. The main purpose of this prospective in vitro study that was the Micro-CT evaluation of teeth crown and root pulp volume versus dentin thickness in terms of PMI determination. The study involved 60 female Wistar rats, with weights ranging from 270 to 320g. These rats were grouped into six different post-mortem period categories. Following the animals' sacrifice, they were subjected to a natural putrefaction period, with a control group, in the grounds of a sheltered garden. Hemi-mandible samples were then extracted and placed in glass tubes for Micro-CT evaluations, following the progression of putrefaction processes. The pulp volume and dentin thickness were assessed using Micro-CT, and the gathered data underwent statistical analysis. Micro-CT was employed to analyze sixty right mandibular second molar teeth in the hemi-mandible. The crown pulp volume exhibited a reduction in group 6, with a value of 0.239 mm3 after a three-month period of natural putrefaction (p < 0.001). There is statistically differences among groups in case of pairwise comparison (p < 0.05). However, the root pulp volume and dentin thickness variables did not display any statistically significant changes. Despite certain limitations associated with this study, the Micro-CT findings concerning teeth pulp volume can serve as an objective parameter, especially for late postmortem investigations and the estimation of time of death.

Determination of Postmortem Interval in Mice.

Despite the major use of mice in biomedical research, little information is available with regard to identifying their postmortem changes and using that information to determine the postmortem interval (PMI), defined as the time after death. Both PMI and environmental conditions influence decomposition (autolysis and putrefaction) and other postmortem changes. Severe decomposition compromises lesion interpretation and disease detection and wastes limited pathology resources. The goal of this study was to assess postmortem changes in mice in room temperature cage conditions and under refrigeration at 4 °C to develop gross criteria for the potential value of further gross and histologic evaluation. We used 108 experimentally naïve C57BL/6 mice that were humanely euthanized and then allocated them into 2 experimental groups for evaluation of postmortem change: room temperature (20 to 22 °C) or refrigeration (4 °C). PMI assessments, including gross changes and histologic scoring, were performed at hours 0, 4, 8, and 12 and on days 1 to 14. Factors such as temperature, humidity, ammonia in the cage, and weight change were also documented. Our data indicates that carcasses held at room temperature decomposed faster than refrigerated carcasses. For most tissues, decomposition was evident by 12 h at room temperature as compared with 5 d under refrigeration. At room temperature, gross changes were present by day 2 as compared with day 7 under refrigeration. Mice at room temperature lost 0.78% of their baseline body weight per day as compared with 0.06% for refrigerated mice (95% CI for difference 0.67% to 0.76%, P < 0.0005). This study supports the consideration of temperature and PMI as important factors affecting the suitability of postmortem tissues for gross and histologic evaluation and indicates that storage of carcasses under refrigeration will significantly slow autolysis.

Accurate Prediction of Death Time via Integrating Microbial Community Dynamics

This study addresses the challenge of accurately estimating Postmortem Interval (PMI), the time since death, employing a data-driven approach. PMI determination is crucial in forensic investigations, and traditional methods often lack precision. We focus on utilizing a data mining approach Regularized Random Forest with cross-validation to enhance PMI prediction accuracy. Unlike conventional methods, our approach incorporates external information about the deceased, recognizing the impact of contextual factors on PMI estimation. Recent advancements have seen statistical methods leveraging dynamic changes in microbial communities to predict PMI. However, accuracy has been hindered by various sources of noise. To overcome this limitation, we propose a novel data mining approach, integrating cross-validation techniques and external information to refine PMI predictions. Through an empirical demonstration, we establish that our approach surpasses existing procedures in terms of accuracy, as validated against published datasets. This research contributes to the advancement of PMI estimation methodologies, emphasizing the importance of incorporating comprehensive data mining techniques and contextual information for more precise forensic applications.

Impact of aluminum phosphide on development of the forensically important fly, Chrysomya albiceps (Diptera: Calliphoridae).

Chrysomya albiceps (Calliphoridae) is among the earliest successional fauna on human and animal cadavers. Some immature Calliphoridae can be useful for determination of post-mortem interval. Toxins, particularly pesticides, can affect the rate of insect growth. Aluminum phosphide (AlP) is an affordable insecticide that has not been adequately entomotoxicologically evaluated. So, the impact of AlP on the developmental rate of different stages of C. albiceps was investigated. Larvae of C. albiceps were reared on the rabbit carcasses containing AlP as a treated group, and distilled water as a control group. The substances were administered by a gastric tube. The duration needed for development of C. albiceps stages was documented. Body length, width and weight of larvae were measured after 24, 48, 72 and 96 h from egg hatching. The duration of development increased significantly in the treated group compared to the control group. Larvae body measurements were significantly smaller in the treated group than in the control group. Therefore, it was demonstrated that AlP significantly influences the size of C. albiceps larvae and extends their development. During forensic application, interpretation of C. albiceps data should be used with caution when aluminum phosphide may be the cause of death.

Forensically Important and Seasonal Changes in Temperatures of Developmental Stages in Life Cycle of Sarcophagidae Fly, Sarcophaga Africa

Sarcophaga Africa is one of the hairy maggot flesh flies that feeds on meat carrion, and dead and decaying matter of animals to complete its life cycle which is useful for post-mortem interval (PMI). Determination in forensic investigations. The actual life cycle hours and days are calculated due to the morphological parameter of the life cycle of Sarcophaga Africa were studied in different seasons; The Life cycle in the rainy season was completed in 270 ± 1.25 hrs (11.25 ± 0.40 days), when the maximum temperature was 27.02°C and the minimum temperature was 26.4°C; in summer season when the maximum temperature was 36.6°C and the minimum temperature 33.2°C, the life cycle was completed in 220± 1.17 hrs (6.16. ± 0.10 days), while in cycle was completed in 310 ± 1.35hrs (12.91 ± 0.21 days) when the maximum and minimum winter season life cm temperatures were 27.4°C and 17.2°C respectively. The temperature plays an important role in determining the developmental stages of the life cycle of Sarcophaga Africa which should be considered during PMI determination. The external parameters of different stages differ from season to season. Larvae were healthy and bigger in the rainy season but in summer were short and small-sized. The size of larvae in the winter season was also smaller than the size in both summer and rainy seasons.

Estimation of postmortem interval using histological and oxidative biomarkers in human bone marrow.

In forensic medicine, estimating the postmortem interval (PMI) is of great importance for the timeline and the reconstruction of the events surrounding death. Bone marrow (BM) is one of the largest organs in the body, with good resistance to autolysis and contamination. Therefore, the present study aims to correlate different postmortem intervals and bone marrow antioxidant enzyme levels using an Enzyme-linked immunosorbent assay (ELISA). In addition, detection of the changes in the histological structure of human bone marrow in relation to the time passed since death. BM samples from 20 forensic autopsy cadavers were obtained from cases referred to the Department of Forensic Medicine in the Ministry of Justice, Dakahlia Governorate, processed for histopathological examination as well as estimation of reduced glutathione (GSH), glutathione peroxidase (GPX), and glutathione reductase (GRX) using ELISA. Results of ELISA analysis showed a significant decrease in the level of antioxidant enzymes with increasing PMI; regarding histopathological examination, from 6 to > 18h PMI, the changes in morphology after death were gradual, progressive, and regular, indicating great value in PMI determination. Also, 18h of PMI showed loss of cellular details, absence of fat cells, and necrosis of BM with the nucleus dispersed as eosinophilic debris. Estimation of antioxidant enzymes level in human bone marrow using ELISA and detection of the changes in the histological structure of human bone marrow in relation to time passed since the death, either separately or in combination, can be used to estimate PMI accurately.

Expression of human cardiac-specific genes: a novel method for post-mortem interval estimation.

In legal medicine, the determination of post-mortem interval (PMI) is not only an important but also one of the most difficult aspects. Several methods are used to estimate PMI such as physicochemical, entomological, biochemical, metabolic, autolytic, and physical methods. These methods provide a wide range of PMI as they are affected by different factors. The approach behind the present study is to calculate an accurate PMI by using mRNA degradation and fold change expression (FCE) of cardiac-specific genes viz. N-terminal pro-B-type natriuretic peptide (NPPB) and cardiac troponin I (TNNI3). Seventeen cadaver heart tissues were analysed within a time frame of up to 12 hours from the time since death, at different time intervals at room temperature. Gene expression was determined and the data were analysed using the value of average delta Ct (ΔCt) value of the assessed gene and housekeeping gene. Delta delta Ct (ΔΔCt) method was used to calculate the FCE at the different 7-time groups. The FCE of TNNI3 was almost stable till 15 hours of PMI and then after 15 hours, expression shows a decrease up to 24 hours after death; whereas, NPPB shows that FCE was stable till 12 hours of PMI and then after 12 hours, expression shows a decrease up to 24 hours after death. The FCE of NPPB and TNNI3 was almost stable till 12 hours. Thus, the estimation of PMI by analysis of the FCE of cardiac-specific genes can be a new promising method in forensic medicine.

The potential of using non-coding RNAs in forensic science applications.

With the continuous development and integration of molecular biology and forensic science, non-coding RNAs (ncRNAs), especially ncRNAs with regulatory functions such as microRNA, long non-coding RNA, and circular RNA, have recently been actively explored by forensic scholars. In this study, we review the literature on these ncRNAs in various fields of forensic science, including postmortem interval determination, wound age estimation, forensic age assessment, cause of death analysis, and body fluid identification, aiming to evaluate the current research and provide a perspective for future applications.

Estimating the time of human decomposition based on skeletal muscle biopsy samples utilizing an untargeted LC-MS/MS-based proteomics approach.

Accurate estimation of the postmortem interval (PMI) is crucial in forensic medico-legal investigations to understand case circumstances (e.g. narrowing down list of missing persons or include/exclude suspects). Due to the complex decomposition chemistry, estimation of PMI remains challenging and currently often relies on the subjective visual assessment of gross morphological/taphonomic changes of a body during decomposition or entomological data. The aim of the current study was to investigate the human decomposition process up to 3months after death and propose novel time-dependent biomarkers (peptide ratios) for the estimation of decomposition time. An untargeted liquid chromatography tandem mass spectrometry-based bottom-up proteomics workflow (ion mobility separated) was utilized to analyse skeletal muscle, collected repeatedly from nine body donors decomposing in an open eucalypt woodland environment in Australia. Additionally, general analytical considerations for large-scale proteomics studies for PMI determination are raised and discussed. Multiple peptide ratios (human origin) were successfully proposed (subgroups < 200 accumulated degree days (ADD), < 655 ADD and < 1535 ADD) as a first step towards generalised, objective biochemical estimation of decomposition time. Furthermore, peptide ratios for donor-specific intrinsic factors (sex and body mass) were found. Search of peptide data against a bacterial database did not yield any results most likely due to the low abundance of bacterial proteins within the collected human biopsy samples. For comprehensive time-dependent modelling, increased donor number would be necessary along with targeted confirmation of proposed peptides. Overall, the presented results provide valuable information that aid in the understanding and estimation of the human decomposition processes.

Effect of Pesticide Poison on Post-Mortem Interval Determination Based on Entomological Study

Determination of post-mortem intervals (PMI) is a major key in forensic investigation. On the discovery of a decomposed corpse, a post mortem examination is difficult. PMI can be made by observation of insects that appear around the corpse, called forensic entomology. Forensic entomology carried out by analyzing the species of larvae and calculating the age of insects so that the time of death can be estimated. Forensic entomology has been developed in toxicological examinations so that insects found can be used as toxicological samples. The cause of death can be due to poisoning. Poisons often used in case of poisoning or suicide is pesticides. This research is a Systematic Review, a study that takes and collects data from various previous studies related to the chosen theme. The study was conducted according to protocol and registration with reference to PRISMA and JBI. Literature searches are obtained from online databases. The results were obtained by 21 studies after selection and elimination in accordance with protocol. The most accurate determination of the post mortem interval depends on post-death changes and the decomposition process. Some types of pesticides can cause the decomposition process to take place faster but some other types of pesticides can slow down the decomposition process. The content of toxins in the body ingested has an effect on the development and growth of necrophagous insects. The growth of flies will be stunted or even stopped, the presence of toxins in the corpse can be a contributing factor in the determination of the post-mortem interval. Deaths caused by toxins still need to be further researched because different types of toxins can show different side effects on the body.

Effect of temporary freezing on postmortem protein degradation patterns

BackgroundA precise determination of time since death plays a major role in forensic routine. Currently available techniques for estimating the postmortem interval (PMI) are restricted to specific time periods or cannot be applied for individual case-specific reasons. During recent years, it has been repeatedly demonstrated that Western blot analysis of postmortem muscle protein degradation can substantially contribute to overcome these limitations in cases with different background. Enabling to delimit time points at which certain marker proteins undergo distinct degradation events, the method has become a reasonable new tool for PMI delimitation under various forensic scenarios. However, additional research is yet required to improve our understanding of protein decomposition and how it is affected by intrinsic and extrinsic factors.Since there are temperature limits for proteolysis, and investigators are confronted with frozen corpses, investigation of the effects of freezing and thawing on postmortem protein decomposition in the muscle tissue is an important objective to firmly establish the new method. It is also important because freezing is often the only practical means to intermittently preserve tissue samples from both true cases and animal model research.MethodsSets of dismembered pig hind limbs, either freshly detached non-frozen, or thawed after 4 months of freeze-storage (n = 6 each), were left to decompose under controlled conditions at 30 °C for 7 days and 10 days, respectively. Samples of the M. biceps femoris were regularly collected at predefined time points. All samples were processed via SDS-PAGE and Western blotting to identify the degradation patterns of previously characterized muscle proteins.ResultsWestern blots show that the proteins degrade predictably over time in precise patterns that are largely unaffected by the freeze-and-thaw process. Investigated proteins showed complete degradation of the native protein band, partly giving rise to degradation products present in distinct time phases of the decomposition process.ConclusionThis study provides substantial new information from a porcine model to assess the degree of bias that freezing and thawing induces on postmortem degradation of skeletal muscle proteins. Results support that a freeze–thaw cycle with prolonged storage in frozen state has no significant impact on the decomposition behavior. This will help to equip the protein degradation–based method for PMI determination with a robust applicability in the normal forensic setting.

Influence of the ear temperature range on the measurement bias between an infrared thermometer and a reference probe for post-mortem interval determination

The aim of this study was to assess the influence of the post-mortem outer ear temperature (OET) on the measurement bias previously observed for short post-mortem intervals (PMI) between a commercially available infrared thermometer and a reference metal probe thermometer. To that end, 100 refrigerated bodies were added to our initial cohort to investigate lower OET. In contrast to our previous findings, a very good concordance was noted between both methods. There was still an overall underestimation of ear temperatures with the infrared thermometer, but the average bias was significantly reduced compared to that observed in the initial cohort (1.47 °C for the right ear and 1.32 °C for the left ear). Most importantly, this bias progressively decreased as the OET decreased, becoming negligible for OET lower than 20 °C. These results are in agreement with literature data regarding these temperature ranges. The discrepancy observed with our previous observations may be due to the technical characteristics of the infrared thermometers. The lower the temperatures measured, the more the measurements approach the lower limit of the measuring range of the device and tend to give constant values, resulting in a smaller underestimation of the measurements. Further research is needed to assess the interest of integrating in the already validated OET-based formulae a variable dependent on the temperature measured with the infrared thermometer, to eventually allow infrared thermometry to be used for PMI estimation in forensic practice.

Determination of postmortem interval and cause of death: Do the levels of biochemical parameters in vitreous humor provide an additional assistance to medico legal expert?

An upward rise has been observed in the pattern of unnatural deaths in the recent years and the same has been found during the post mortem examination. During the trial in the court of law prosecution as well as defense require the time passed death before examination and the cause of death in particular circumstances, as it is mandatory to fix the exact duration either to punish the guilty or NOT to punish the innocent. Vitreous humor is different from other body fluids as it has relative stability in its composition so as also biochemical parameters. It was further hypothesized that postmortem vitreous humor biochemistry closely mimics antemortem serum biochemistry and may be a useful aid in establishing postmortem diagnoses. Various studies have been carried out on vitreous electrolyte concentration changes to arrive at postmortem interval. Many workers found the importance of potassium in the determination of postmortem interval, whereas among all the biochemical parameters, vitreous potassium is found to be more useful to find out time since death. Postmortem biochemical analysis of vitreous humor may be helpful in the establishment of antemortem disease or metabolic disorder. The present study was carried out jointly in department of Forensic Medicine and Toxicology and department of Biochemistry of Surat Municipal Institute of Medical Education &amp; Research (SMIMER), Surat. A total of 100 subjects were taken up for this study. The samples were collected from dead bodies during postmortem examination with all aseptic precautions. A detailed performa was made with all the details of age, sex, length, weight and date and time of admission, date and time of death and manner of death such as suicide, homicide, sudden death and accidents was recorded. Cases below 15 years of age were not considered in this study. Out of 100 cases there were 24 (24%) females and 76 (76%) were males, out of these 56% were between 15-35 years, 32% were of 36-55 years, 9% were of 56-65 years, and 3% were of 66-77 years age group. According to the manner of death 50 subjects were of accident, 26 subjects were of sudden death, 21 subjects were of suicide and 3 subjects were of homicide. According to time interval between sample collection and time of death, 47 subjects were of 0-24 hours, 36 subjects were of 24-48 hours, 11 subjects were of 48-72 hours and 6 subjects were of 72-96 hours. In present study we observed that there is definitive correlation between time of death and changes in level of these biochemical parameters. This was a preliminary study in this region and can be considered as a pilot study. The levels of vitreous Potassium have been found to be significantly altered as the time progresses after death. A progressive decrease in sodium/potassium and increase in potassium/ calcium ratios was also observed.

Significance of Forensic Fly and Seasonal Variation in the Temperature of Developmental Stages in Lifecycle for Family Sarcophagidae, Sarcophaga Africa

Sarcophaga Africa, is one of the hairy maggot flesh flies which feeds on meat carrion, and dead and decaying matter of animals to the completes its life cycle which is the useful for post mortem interval (PMI). Determination in forensic investigations. The actual life cycle hours and days are calculated due to their morphological parameter of their life cycle of Sarcophaga Africa were studied in different seasons; Life cycle in rainy season was completed in 270± 1.25 hrs (11.25 ± 0.40 days), when the maximum temperature was 27.02°C and the minimum temperature was 26.4°C; in summer season when the maximum temperature was 36.6°C and the minimum temperature 33.2°C, the life cycle was completed in 220± 1.17 hrs (6.16. ± 0.10 days), while in cycle was completed in 310 ± 1.35hrs (12.91 ± 0.21 days) when the maximum and minimum winter season life cm temperatures were 27.4°C and 17.2°C respectively. The temperature is the important role to determine the developmental stages of life cycle of Sarcophaga Africa which should be considered during PMI determination. The external parameters of different stages differ from season to season. Larvae were healthy and bigger in size in rainy season but in summer were short and small sized. The size of larvae in winter season was also smaller than the size in both summer and rainy seasons.

Characteristics of histochemical, molecular genetic and radiation-induced liver changes depending on the postmortem interval

The aim of this study is to analyze literature data on postmortem changes in the liver and their use in determination of postmortem interval. Biological death expectedly causes the development of postmortem disorders not only in the liver structure, but also changes in its biochemical and histochemical parameters. Literature data about changes of histochemical, immunohistochemical and biomolecular characteristics of liver tissue, as well as bacterial migration to the liver depending on the duration of postmortem period, are presented. The effectiveness of radiology for visualization of postmortem changes and, accordingly, for determining the postmortem interval is noted.

Inferring the Postmortem Interval of Rat Cadaver after Boiling Water Treatment Based on Microbial Community Succession

Abstract Background: In forensic investigations, accurate estimation of the postmortem interval (PMI) is an important task, but also an ongoing challenge. Especially in cases where the cadaver has been specially treated, for example, by boiling, the determination of PMI becomes extremely difficult. Previous studies have shown that the succession of the microbial community after decomposition of the cadaver can be used to infer PMI. However, the feasibility of determining the PMI of boiled cadavers has not yet been demonstrated. Aims and Objectives: The main objective of this study was to test whether we can infer PMI of boiled cadavers based on the succession of microbial communities. Materials and Methods: SD rats were killed by cervical dislocation. Subsequently, the rat cadavers were divided into the case (boiled cadavers) and control (unboiled cadavers) groups. Rectal samples were collected from the rats for 45 days and at nine time points. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community in the rectum. Results: The results showed that the composition and relative abundance of bacterial communities at the phylum level were significantly different between the case and control groups. The alpha diversity of the microbial community showed a decreasing trend with the decomposition process. Principal coordinate analysis showed that the case and control groups had obvious patterns along the succession of microbial communities. The rectal microbial communities showed a significant linear trend in the time course of decomposition. A random forest model was used to infer PMI. The goodness-of-fit (R2) of the model was 68.00% and 84.00%, and the mean absolute errors were 2.05 and 1.48 days within 45 days of decomposition for the case and control groups, respectively. Conclusions: Our results suggest that microbial community succession could be a potential method to infer PMI of boiled cadavers.

Evaluation of elements in human dental tissue in terms of determination of postmortem interval: Experimental study

Despite many methods, there has not been a method yet that exactly determines PMI. This study aims to examine the relationship between the element levels in the dental tissue and the postmortem process in a corpse whose exact time of death is unknown and in the open field and to evaluate its use in determining the time of death by evaluating the increase-decrease-changes. For the study, the healthy and extracted third molars of the patients who applied to the Oral and Maxillofacial Surgery Polyclinic for the extraction of their third molars for various reasons and whose third molars were extracted by the dentists were taken. The samples were divided into 6 groups, with 10 samples in each group. The teeth were left to decay in the open air in a jaw-like plastic model. Na, Mg, P, Ca, Fe, Mn, Co, Zn, Cd, Pb, and Si elements were measured using Inductively Coupled Plasma-Mass Spectrometer analysis method. In our study, it was determined that there were statistically significant changes in the Na, Mg, Fe, Co, Pb, Si elements in the tooth structure. For the Co and Na elements, 2 regression equations were created that can be used to predict the time of death. This work showed that postmortem tooth element concentration changes can be used to predict the time of death. As a result of experiments that will cover longer periods with more elements and be carried out in different environments, a great contribution will be made to the subject of estimation of time of death which is not clear yet.

POST-MORTEM INTERVAL ESTIMATION BASED ON LIVER AND STRIATED MUSCLE COMPUTED TOMOGRAPHY ATTENUATIONS IN RATS

OBJECTIVE: The interest on post-mortem computed tomographic studies targeting post-mortem interval (PMI) estimations is increasing. Most studies have been conducted in an uncontrolled or relatively less controlled condition. However, this study investigates the usefulness of computed tomography attenuations of the liver and striated muscles in PMI estimation under strictly controlled environmental conditions. MATERIAL AND METHODS: Post-mortem computed tomography images of 30 Wistar Albino rats were obtained in the first 30 min after death and 12, 24, 36, 48, 72, 96, 120, 144 and 168-hours following death. Repeated attenuations of both thelateral lobes of the liver and paraspinal muscle were recorded in 0.12-cm2 regions of interest. RESULTS: The attenuation values of the liver and paraspinal muscles were higher 12-hour post-mortem. A significant difference was observed between the images obtained 30 minutes post-mortem and those obtained 12 hours post-mortem in both male (p=0.01) and female rats (p=0.01). Different cut-off attenuation values for the liver and muscle tissue were determined to estimate the post-mortem interval. CONCLUSIONS: The use of attenuation values of the liver and striated muscles with the proposed model was found to be beneficial for the determination of PMI. The cut-off values of attenuation, especially for the liver, can be used in the delimitation of the post-mortem interval.