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Background: Post-mortem interval (PMI) is the cornerstone of the forensic field to investigate. The examination technique by seeing the changes in the body such as algor mortis, rigor mortis, and livor mortis is a traditional technique in which accuracy is influenced by many factors. A biomolecular technique that uses microRNA (miRNA) biomarkers is developing because miRNA has good stability than other RNA, so it meets the requirements to be used for PMI estimation. Method: Following the PRISMA guidelines, journals were taken from 5 databases: Scopus, Science Direct, PubMed, Embase, and Springer. The review was carried out by two people. Inclusion criteria in this review are original research, published in the last 10 years, discussing miRNA as a biomarker for PMI estimation, and free full access. While exclusion criteria are not original research and not using English. Result: Eighteen journals were reviewed in this study. The study was conducted using test animals (rats) and human samples with tissue sources taken from the liver, skeletal muscle, blood, bone, heart, skin, saliva, semen, brain, lung, vitreous humor, spleen, and kidney. miRNA expression levels after death showed different results based on miRNA target, tissue source, and others. Discussion: The results of each study are different due to the use of different types of miRNA targets and tissue sources. miRNA has great potential to estimate PMI in forensic science, but it is necessary to control the influencing factors to obtain an accurate conclusion. [ABSTRACT FROM AUTHOR]

The search for diatoms is the test that most of all may contribute to the forensic diagnosis of drowning. Diatoms can be extracted through different methods, which are all complex and long. In this preliminary study, we assessed human vitreous humor as an innovative substrate on which to research diatoms. Sampling and analyses were performed on 3 groups of 10 corpses each. The first one was composed of drowned victims. The second one of victims of traffic accidents with subsequent projection in water; based on the severe traumatic injuries reported at autopsy, we considered such victims as ideally assimilable to bodies immersed in water postmortem. The third group was composed of subjects who died for natural causes and without any relationship with water. The vitreous humor was centrifugated and cytocentrifuged and spotted on two different histological slides: one was left blank and the other one was assessed with hematoxylin and eosin staining. Microscopic observation successfully revealed diatoms in all cases of the first group; in the second group diatoms were not detected in 6 cases; in the third group, no diatoms at all were observed. Diatoms were always qualitatively and quantitatively consistent with those found in the corresponding viscera and waters, which had been investigated through classical acid digestion. Our analyses have demonstrated that the vitreous humor behaves in a completely similar way to the other viscera in cases of drowning. Although further investigations are necessary, vitreous humor has proved to be an innovative, suitable, and reliable substrate for the forensic research of diatoms. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) is a major cause of death and its accurate diagnosis is an important concern of daily forensic practice. However, it can be challenging to diagnose TBI in cases where macroscopic signs of the traumatic head impact are lacking and little is known about the circumstances of death. In recent years, several post-mortem studies investigated the possible use of biomarkers for providing objective evidence for TBIs as the cause of death or to estimate the survival time and time since death of the deceased. This work systematically reviewed the available scientific literature on TBI-related biomarkers to be used for forensic purposes. Post-mortem TBI-related biomarkers are an emerging and promising resource to provide objective evidence for cause of death determinations as well as survival time and potentially even time since death estimations. This literature review of forensically used TBI-biomarkers revealed that current markers have low specificity for TBIs and only provide limited information with regards to survival time estimations and time since death estimations. Overall, TBI fatality-related biomarkers are largely unexplored in compartments that are easily accessible during autopsies such as urine and vitreous humor. Future research on forensic biomarkers requires a strict distinction of TBI fatalities from control groups, sufficient sample sizes, combinations of currently established biomarkers, and novel approaches such as metabolomics and mi-RNAs. [ABSTRACT FROM AUTHOR]

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed. [ABSTRACT FROM AUTHOR]

Purpose: The detection and quantification of metabolites relevant for the diagnosis of fatal metabolic disorders by proton magnetic resonance spectroscopy (1H-MRS) was recently demonstrated. This prospective study aimed to compare the concentrations of beta-hydroxybutyrate (BHB), glucose (GLC), and lactate (LAC) derived from both biochemical analyses and 1H-MRS for the diagnosis of fatal metabolic disorders. Methods: In total, 20 cases with suspected fatal metabolic disorders were included in the study. For the agreement based on thresholds, the concentrations of BHB and GLC in the vitreous humor (VH) from the right vitreous and in cerebrospinal fluid (CSF) from the right lateral ventricle were derived from 1H-MRS and biochemical analyses. The predefined thresholds for pathological elevations were 2.5 mmol/l for BHB and 10 mmol/l for GLC based on the literature. In addition, concentrations of the same metabolites in white matter (WM) tissue from the corona radiata of the right hemisphere were analyzed experimentally using both methods. To enable the biochemical analysis, a dialysate of WM tissue was produced. For all three regions, the LAC concentration was determined by both methods. Results: The conclusive agreement based on thresholds was almost perfect between both methods with only one disagreement in a total of 70 comparisons due to the interference of a ferromagnetic dental brace. The differences in the concentrations between both methods showed high standard deviations. Confidence intervals of the bias not including 0 were found in CSF-GLC (− 3.1 mmol/l), WM-GLC (1.1 mmol/l), and WM-LAC (− 6.5 mmol/l). Conclusion: Despite a considerable total error attributable to both methods, MRS derives the same forensic conclusions as conventional biochemical analyses. An adaptation of the protocol to reduce the detected errors and more data are needed for the long-term validation of MRS for the diagnosis of fatal metabolic disorders. The production of WM dialysates cannot be recommended due to high glycolytic loss. [ABSTRACT FROM AUTHOR]

Hyponatremia is defined as a plasma sodium concentration less than 135 or 130 mEq/L (or mmol/L) and may be responsible for life threatening symptoms that can be observed in a variety of medical conditions. Cases of fatal hyponatremia have been reported in both clinical and forensic literature in situations of water intoxication due to psychogenic polydipsia, amphetamine derivative drug intake, high-endurance exercise, iatrogenic causes, and exceptional cases of child abuse by forced water intoxication. Vitreous sodium levels have been determined to be relatively stable during the early postmortem period and similar to levels found in normal serum of living subjects. Nevertheless, there are relatively few cases of fatal hyponatremia described in literature that underwent exhaustive postmortem biochemical investigations. A case of fatal water intoxication in a psychiatric patient who underwent medicolegal investigations, including postmortem biochemistry, was chosen as a starting point to a literature review of deaths by hyponatremia that may be encountered in the forensic setting. [ABSTRACT FROM AUTHOR]

The aim of this study was to measure catecholamines and their O-methylated metabolites in urine and vitreous humor collected in cardiac deaths and noncardiac control cases that underwent medicolegal investigations. Our first goal was to assess whether cardiac events of different types are characterized by different catecholamine/metanephrine urine and/or vitreous profiles. Our second goal was to determine whether noncardiac causes of death with different survival intervals are characterized by different catecholamine/metanephrine urine and/or vitreous profiles. Two study groups were prospectively and retrospectively formed, a cardiac death group (including three subgroups, according to the cause of death) and a noncardiac death group (including two subgroups, according to the length of the agonal period). Postmortem angiography, autopsy, histology, toxicology, and biochemistry were performed in all cases. First results seem to indicate that absolute values measured in urine and vitreous for each of the analyzed markers display no significant differences relating to each of the tested cardiac death subgroups. In the control group, absolute concentrations measured in urine and vitreous for each of the analyzed parameters failed to show significant differences relating to the length of agonal period. Our preliminary findings do not seem to confirm the conclusions of former studies and fail to corroborate the usefulness of urine catecholamine and metanephrine analysis to characterize stress response intensity or length of the dying process in the postmortem setting. [ABSTRACT FROM AUTHOR]

Urea nitrogen, creatinine, and uric acid are relatively stable in postmortem serum and may, therefore, be used for diagnostic purposes when chronic kidney disease and end-stage renal failure are investigated as causes of death. Nevertheless, uncertainties remain in defining the best alternative to postmortem serum for the identification and assessment of significantly decreased kidney function. In this study, we investigated urea nitrogen, creatinine, and uric acid levels in postmortem serum, pericardial fluid, and vitreous humor in a series of medico-legal cases (500 autopsies) with various causes of death. No postmortem interval-related differences were observed in any of the investigated fluids for any analyzed parameter, confirming the biochemical stability of all compounds after death. Data analysis failed to reveal statistically significant differences between postmortem serum and pericardial fluid urea nitrogen, creatinine, and uric acid concentrations. Conversely, statistically significant differences were observed in all analyzed biomarkers between postmortem serum and vitreous humor levels, with lower concentrations of all markers measured in vitreous. The results of this study suggest that, in order to estimate as accurately as possible blood analyte concentrations at the time of death, pericardial fluid should be preferred to vitreous humor. [ABSTRACT FROM AUTHOR]

When interpreting gamma-hydroxybutyric acid (GHB) concentrations in post-mortem specimens, a possible increase in GHB concentrations because of post-mortem generation must be considered. In this study, endogenous GHB concentrations in post-mortem biological fluids were investigated. Additionally, we review post-mortem GHB concentrations already published in the literature. Heart and peripheral blood samples, cerebrospinal fluid, urine, and vitreous humor were collected from 64 autopsies in subjects where the cause of death excluded GHB exposure. Sample analysis was carried out either on the day of autopsy or later after immediate freezing and storage at −20 °C. GHB concentrations in venous blood samples ( n = 61) were <0.6-28.7 mg/L (mean 11.9 mg/L; median 10.6 mg/L), <0.6-65.3 mg/L (mean 15.2 mg/L; median 12.8 mg/L) in heart blood ( n = 56), <0.6-25.1 mg/L (mean 6.0 mg/L; median 3.8 mg/L) in urine ( n = 50), <0.6-39.0 mg/L (mean 9.6 mg/L; median 7.5 mg/L), in vitreous humor ( n = 54), and <0.6-24.0 mg/L (mean 4.2 mg/L; median 3.2 mg/L) in cerebrospinal fluid ( n = 52). There was no significant difference between GHB concentrations in cases where there were signs of beginning putrefaction at the time of autopsy ( n = 9) and cases without obvious signs of putrefaction. In one case with advanced putrefaction, the GHB concentration in venous blood was 32.7 mg/L. In conclusion, for post-mortem venous blood, urine, and cerebrospinal fluid, an interpretative cut-off of 30 mg/L for GHB concentrations is suggested in cases where GHB analysis is conducted on the day of sample collection at autopsy or if samples have been stored at −20 °C immediately after collection. [ABSTRACT FROM AUTHOR]

We hypothesized that miRNAs present in vitreous humor could be a sort of 'biological black box,' storing information about physiological and environmental circumstances at death. As a proof of concept, we analyzed the vitreous humor miRNA signature to explore its forensic potential applications, such as determining the time of the day at death. The miRNAs present in vitreous humor from individuals who died at daytime or at nighttime were analyzed by quantitative real-time polymerase chain reaction (qPCR) array. Target miRNAs showing significant differences between groups were studied in a larger sample by individual qPCR assays. After array analysis of miRNAs in seven samples, significant expression differences were detected between individuals who died at daytime and at nighttime regarding mir-34c, mir-541, mir-888, mir-484, and mir-142-5p. miR-222 appeared as the best reference gene. The results were replicated in 34 vitreous humor samples, and the day-night differences were confirmed for miR-142-5p and miR-541, suggesting that miRNA levels may be related to either the ambient light or the circadian clock at the time of death. There was no correlation between miRNA levels and the time elapsed after death, suggesting that they were stable at least for 24 h. In conclusion, this report supports the potential forensic utility of the analysis of miRNAs in the vitreous humor in applications such as determining the time of death. [ABSTRACT FROM AUTHOR]

According to the hypothesis of Traub, also known as the 'formula of Traub', postmortem values of glucose and lactate found in the cerebrospinal fluid or vitreous humor are considered indicators of antemortem blood glucose levels. However, because the lactate concentration increases in the vitreous and cerebrospinal fluid after death, some authors postulated that using the sum value to estimate antemortem blood glucose levels could lead to an overestimation of the cases of glucose metabolic disorders with fatal outcomes, such as diabetic ketoacidosis. The aim of our study, performed on 470 consecutive forensic cases, was to ascertain the advantages of the sum value to estimate antemortem blood glucose concentrations and, consequently, to rule out fatal diabetic ketoacidosis as the cause of death. Other biochemical parameters, such as blood 3-beta-hydroxybutyrate, acetoacetate, acetone, glycated haemoglobin and urine glucose levels, were also determined. In addition, postmortem native CT scan, autopsy, histology, neuropathology and toxicology were performed to confirm diabetic ketoacidosis as the cause of death. According to our results, the sum value does not add any further information for the estimation of antemortem blood glucose concentration. The vitreous glucose concentration appears to be the most reliable marker to estimate antemortem hyperglycaemia and, along with the determination of other biochemical markers (such as blood acetone and 3-beta-hydroxybutyrate, urine glucose and glycated haemoglobin), to confirm diabetic ketoacidosis as the cause of death. [ABSTRACT FROM AUTHOR]

Postmortem chemistry is becoming increasingly essential in the forensic pathology routine and considerable progress has been made over the past years. Biochemical analyses of vitreous humor, cerebrospinal fluid, blood and urine may provide significant information in determining the cause of death or in elucidating forensic cases. Postmortem chemistry may essentially contribute in the determination of the cause of death when the pathophysiological changes involved in the death process cannot be detected by morphological methods (e.g. diabetes mellitus, alcoholic ketoacidosis and electrolytic disorders). It can also provide significant information and useful support in other forensic situations, including anaphylaxis, hypothermia, sepsis and hormonal disturbances. In this article, we present a review of the literature that covers this vast topic and we report the results of our observations. We have focused our attention on glucose metabolism, renal function and electrolytic disorders. [ABSTRACT FROM AUTHOR]

The use of vitreous humor (VH) as an alternative matrix to blood in the field of forensic toxicology has been described for numerous drugs. Interpretation of drug concentrations measured in VH, as in other matrices, requires statistical analysis of a data set obtained on a significant series. In the present study, two diagnostic tests interpreting postmortem VH concentrations of meprobamate in 117 sets of autopsy data are reported. (1) A VH meprobamate concentration threshold of 28 mg/l was statistically equivalent to that of blood meprobamate concentration threshold of 50 mg/l distinguishing overdose from therapeutic use in blood. The intrinsic qualities of the test were good, with sensitivity of 0.95 and absolute specificity of 1. (2) A novel interpretation tool is proposed, allowing blood concentration range to be evaluated, with a known probability, from VH concentration. [ABSTRACT FROM AUTHOR]

In clinical practice, biochemical markers, particularly serum glucose levels are used to diagnose diabetes mellitus. However, at autopsy this marker is of no value due to the substantial and capricious fluctuations in glucose levels after death. The aim of this study was to evaluate the usefulness of the postmortem determination of fructosamine in vitreous humor for confirming the presence of antemortem hyperglycemia. This was a study of 92 cadavers with a mean age of 60.05 years (SD 17.73) and a mean postmortem interval of 17.02 h (SD 9.76, range 2–58 h). Cases were assigned to two diagnostic groups according to the antemortem diagnosis of diabetes mellitus based on the patients’ medical records. In vitreous humor statistically significant differences were found in glucose and fructosamine concentrations between the two diagnostic groups, the highest values being obtained in the group of subjects with a previous diagnosis of diabetes mellitus. [ABSTRACT FROM AUTHOR]