Postmortem serum protein S100B levels with regard to the cause of death involving brain damage in medicolegal autopsy cases

Neuroforensomics: metabolites as valuable biomarkers in cerebrospinal fluid of lethal traumatic brain injuries

Traumatic brain injury (TBI) is a ubiquitous, common sequela of accidents with an annual prevalence of several million cases worldwide. In forensic pathology, structural proteins of the cellular compartments of the CNS in serum and cerebrospinal fluid (CSF) have been predominantly used so far as markers of an acute trauma reaction for the biochemical assessment of neuropathological changes after TBI. The analysis of endogenous metabolites offers an innovative approach that has not yet been considered widely in the assessment of causes and circumstances of death, for example after TBI. The present study, therefore, addresses the question whether the detection of metabolites by liquid-chromatography-mass spectrometry (LC/MS) analysis in post mortem CSF is suitable to identify TBI and to distinguish it from acute cardiovascular control fatalities (CVF). Metabolite analysis of 60 CSF samples collected during autopsies was performed using high resolution (HR)-LC/MS. Subsequent statistical and graphical evaluation as well as the calculation of a TBI/CVF quotient yielded promising results: numerous metabolites were identified that showed significant concentration differences in the post mortem CSF for lethal acute TBI (survival times up to 90 min) compared to CVF. For the first time, this forensic study provides an evaluation of a new generation of biomarkers for diagnosing TBI in the differentiation to other causes of death, here CVF, as surrogate markers for the post mortem assessment of complex neuropathological processes in the CNS ("neuroforensomics").

The Role of Protein Degradation in Estimation Postmortem Interval and Confirmation of Cause of Death in Forensic Pathology: A Literature Review

It is well known that proteins are important bio-macromolecules in human organisms, and numerous proteins are widely used in the clinical practice, whereas their application in forensic science is currently limited. This limitation is mainly attributed to the postmortem degradation of targeted proteins, which can significantly impact final conclusions. In the last decade, numerous methods have been established to detect the protein from a forensic perspective, and some of the postmortem proteins have been applied in forensic practice. To better understand the emerging issues and challenges in postmortem proteins, we have reviewed the current application of protein technologies at postmortem in forensic practice. Meanwhile, we discuss the application of proteins in identifying the cause of death, and postmortem interval (PMI). Finally, we highlight the interpretability and limitations of postmortem protein challenges. We believe that utilizing the multi-omics method can enhance the comprehensiveness of applying proteins in forensic practice.

Forensic biomarkers of lethal traumatic brain injury

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.

Assessing Protein Biomarkers to Detect Lethal Acute Traumatic Brain Injuries in Cerebrospinal Fluid

Diagnosing traumatic brain injury (TBI) from body fluids in cases where there are no obvious external signs of impact would be useful for emergency physicians and forensic pathologists alike. None of the previous attempts has so far succeeded in establishing a single biomarker to reliably detect TBI with regards to the sensitivity: specificity ratio in a post mortem setting. This study investigated a combination of body fluid biomarkers (obtained post mortem), which may be a step towards increasing the accuracy of biochemical TBI detection. In this study, serum and cerebrospinal fluid (CSF) samples from 30 acute lethal TBI cases and 70 controls without a TBI-related cause of death were evaluated for the following eight TBI-related biomarkers: brain-derived neurotrophic factor (BDNF), ferritin, glial fibrillary acidic protein (GFAP), interleukin 6 (IL-6), lactate dehydrogenase, neutrophil gelatinase-associated lipocalin (NGAL), neuron-specific enolase and S100 calcium-binding protein B. Correlations among the individual TBI biomarkers were assessed, and a specificity-accentuated threshold value analysis was conducted for all biomarkers. Based on these values, a decision tree modelling approach was performed to assess the most accurate biomarker combination to detect acute lethal TBIs. The results showed that 92.45% of acute lethal TBIs were able to be diagnosed using a combination of IL-6 and GFAP in CSF. The probability of detecting an acute lethal TBI was moderately increased by GFAP alone and considerably increased by the remaining biomarkers. BDNF and NGAL were almost perfectly correlated (p = 0.002; R² = 0.944). This study provides evidence that acute lethal TBIs can be detected to a high degree of statistical accuracy using forensic biochemistry. The high inter-individual correlations of biomarkers may help to estimate the CSF concentration of an unknown biomarker, using extrapolation techniques.

Brain-dead and coma patients exhibit different serum metabolic profiles: preliminary investigation of a novel diagnostic approach in neurocritical care

There is a clear difference between severe brain damage and brain death. However, in clinical practice, the differentiation of these states can be challenging. Currently, there are no laboratory tools that facilitate brain death diagnosis. The aim of our study was to evaluate the utility of serum metabolomic analysis in differentiating coma patients (CP) from individuals with brain death (BD). Serum samples were collected from 23 adult individuals with established diagnosis of brain death and 24 patients in coma with Glasgow Coma Scale 3 or 4, with no other clinical symptoms of brain death for at least 7 days after sample collection. Serum metabolomic profiles were investigated using proton nuclear magnetic resonance (NMR) spectroscopy. The results obtained were examined by univariate and multivariate data analysis (PCA, PLS-DA, and OPLS-DA). Metabolic profiling allowed us to quantify 43 resonance signals, of which 34 were identified. Multivariate statistical modeling revealed a highly significant separation between coma patients and brain-dead individuals, as well as strong predictive potential. The findings not only highlight the potential of the metabolomic approach for distinguishing patients in coma from those in the state of brain death but also may provide an understanding of the pathogenic mechanisms underlying these conditions.

Significance of detecting postmortem serum IgE in frozen corpses for the diagnosis of anaphylaxis in forensic

The aim of this study was to detect the postmortem serum total IgE levels in frozen corpses and identify whether the death incident caused by an anaphylaxis in forensic medicine. Autopsy cases with pathological death (total, n = 106; 4-214 h postmortem) include cardiac disease (n = 15), pulmonary infection (n = 12), central nervous system disorder (n = 6), pulmonary emboliszn (n = 7), hapetic disease (n = 5), kidney disease (n = 6), enteric disease (n = 10), necrotizing pancreatitis (n = 7), diffuse peritonitis (n = 6), MODS (n = 6), toxicosis (n = 5:), anaphylactic shock (n = 7), bronchial asthma (n = 8) and other disease (n = 6) were examined. Results showed that there was no significant difference between serum IgE levels and ages, postmortem intervals (PMIs), gender as well as survival time. Serum IgE levels of deaths due to anaphylactic shock and bronchial asthma were higher than that of other groups. Forensic pathology examination results showed the main pathology changes of bronchial asthma were mucous congestion in bronchial lumen and eosinophils infiltration in bronchial mucosa. The main pathological features of anaphylactic shock were laryngeal edema and eosinophils infiltration in multiple organs (lung and spleen). This research proved that there was a great significance for IgE to infer whether the individual died due to an anaphylaxis even for a long PMI in frozen corpses. Furthermore, we can also preliminarily determine the type of allergic death combined with the examination of forensic pathology. These findings further verify the feasibility of postmortem serum IgE in the diagnosis of forensic causes of death and broaden the application scope of this marker.

Forensic Biochemical Markers to Evaluate the Agonal Period: A Literature Review

Currently, forensic research is multidisciplinary with new methods and parameters useful to define the cause and time of death as well as survival/agony times. The identification of biochemical markers able to estimate agonal period has been studied by many forensic researchers. It is known that the estimation of agonal time in different types of death is not always easy, hence our interest in literature's data. The studies analyzed in this review confirm the important role of thanatobiochemistry for the estimation of survival times. Regardless of the death cause, the survival/agony time between the primary event and death influences markers concentrations in biological samples (e.g., blood, urine, cerebrospinal fluid). Different biomarkers can be used for qualitative evaluations in deaths with short and long agony (e.g., C-reactive protein, ferritin, GFAP, etc.). Instead, the quantitative interpretation showed limits due to the lack of reference cut-offs. Thanatobiochemistry is a useful tool to confirm what emerged from autopsies findings (macroscopic and histological analysis), but further studies are desirable to confirm the evidence emerging from our review of the literature.

Evaluating the effects of causes of death on postmortem interval estimation by ATR-FTIR spectroscopy

Estimating postmortem interval (PMI) is one of the most challenging tasks in forensic practice due to the effects of many factors. Here, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy combined with chemometrics was utilized to evaluate the effects of causes of death when estimating PMI and to establish a partial least square (PLS) regression model, which can precisely predict PMI under different causes of death. First, the sensitivities to causes of death (brainstem injury, mechanical asphyxia, and hemorrhage shock) of seven kinds of organs were evaluated based on their degrees of cohesion and separation. Then, the liver was selected as the most sensitive organ to establish a PMI estimation model to compare the predicted deviations from different causes of death. It turns out that the cause of death has no significant effect on estimating PMI. Next, a PLS regression model was built with kidney tissues, which have the lowest sensitivity, and this model showed a satisfactory predictive ability and wide applicability. This study demonstrates the feasibility of using ATR-FTIR spectroscopy in conjunction with chemometrics as a powerful alternative for detecting changes in biochemistry and estimating PMI. A new perspective was also provided for evaluating the effect of causes of death when predicting PMI.

Post-mortem in situ stability of serum markers of cerebral damage and acute phase response

The aim of the given study was to test the in situ stability of biochemical markers of cerebral damage and acute phase response in the early post-mortem interval to assess their usability for forensic pathology. A monocentric, prospective study investigated post-mortem femoral venous blood samples at four time points obtained within 48 h post-mortem starting at the death of 20 deceased, using commercial immunoassays for the ten parameters: S100 calcium-binding protein B (S100B), glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), C-reactive protein (CRP), procalcitonin (PCT), ferritin, soluble tumor necrosis factor receptor type 1 (sTNFR1), and lactate dehydrogenase (LDH). Significant changes in serum levels were observed only later than 2 h after death for all markers. Inter-laboratory comparability was high, and intra-assay precision was sufficient for most markers. Most of the biomarker levels depended on the severity of hemolysis and lipemia but were robust against freeze-thaw cycles. Serum levels increased with longer post-mortem intervals for S100B, NSE, ferritin, sTNFR1, and LDH (for all p < 0.001) but decreased over this period for CRP (p = 0.089) and PCT (p < 0.001). Largely unchanged median values were found for GFAP (p = 0.139), BDNF (p = 0.106), and IL-6 (p = 0.094). Serum levels of CRP (p = 0.059) and LDH (p = 0.109) did not differ significantly between the final ante-mortem (resuscitation) and the first post-mortem sample (moment of death). Collecting the post-mortem blood sample as soon as possible will reduce the influence of post-mortem blood changes. Serum GFAP for detection of cerebral damage as well as serum IL-6 and CRP as proof of acute phase response seemed to be preferable due to their in situ stability in the first 2 days after death.

Measurement of Cerebral Biomarkers Proving Traumatic Brain Injuries in Post-Mortem Body Fluids

Until now, it is impossible to identify a fatal traumatic brain injury (TBI) before post-mortem radiological investigations or an autopsy take place. It would be preferable to have an additional diagnostic tool such as post-mortem biochemistry to get greater insight into the pathological pathways and survival times after sustaining TBI. Cerebrospinal fluid (CSF) and serum samples of 84 autopsy cases were collected from forensic autopsies with post-mortem intervals (PMI) of up to 148 h. The cases were categorized into a fatal TBI case group (n = 42) and non-TBI controls (n = 42). The values of glial fibrillary acidic protein (GFAP), brain-derived neurotrophic factor (BDNF), and neutrophil gelatinase-associated lipocalin (NGAL) were analyzed by means of quantitative chemiluminescent multiplex immunoassays. The main results indicate that the usage of liquid samples with good macroscopic quality is more relevant for meaningful biomarker analyses than the length of the PMI. All three proteins were shown to differentiate TBI fatalities from the controls in CSF. In serum, only GFAP could be shown to be able to identify TBI cases. This study is the first approach to measure the three proteins together in CSF and serum in autopsy cases. Determined threshold values may differentiate between fatal TBI and control cases. The presented results emphasize the possible use of post-mortem biochemistry as a supplemental tool in everyday forensic routine.

Post-mortem biochemistry of NSE and S100B: A supplemental tool for detecting a lethal traumatic brain injury?

PURPOSE

Traumatic brain injury (TBI) is a very common entity that leads to numerous fatalities all over the world. Therefore, forensic pathologists are in desperate need of supplemental methodological tools for the diagnosis of TBI in everyday practice besides the standard autopsy. The present study determined post-mortem neuron specific enolase (NSE) and S100 calcium-binding protein B (S100B) levels as biological markers of an underlying TBI in autopsy cases.

METHODS

Paired serum and CSF samples of 92 fatalities were collected throughout routine autopsies. Afterwards, the marker levels were assessed using commercially available immunoassays (ECLIA, Roche Diagnostics). For statistical analysis, we compared the TBI cases to three control groups (sudden natural death by acute myocardial infarction, traumatic death without impact on the head, cerebral hypoxia). Moreover, the TBI cases were subdivided according to their survival time of the trauma. Brain specimens have been collected and stained immunohistochemically against the aforementioned proteins to illustrate their typical cellular staining patterns with an underlying TBI compared to non-TBI fatalities.

PRINCIPAL RESULTS

CSF NSE and S100B levels were elevated after TBI compared to all control groups (p < 0.001). Although this finding can already be investigated among the TBI cases dying immediately subsequent to the trauma, the marker levels in CSF increase with longer survival times until a peak level within the first three days after trauma. There is a strong correlation between both marker levels in CSF (r = 0.67). The presence or absence of cerebral tissue contusion following the initial trauma does not seem to affect the CSF levels of both proteins (p > 0.05). Post-mortem serum levels of both proteins were not elevated in TBI cases compared to controls (p > 0.05). Former elaborated cut-off values in CSF were confirmed and were only exceeded when a TBI survival time of at least 30 min was reached.

MAJOR CONCLUSIONS

The present results report that post-mortem NSE and S100B CSF levels are significantly elevated subsequent to a fatal TBI.

The experimental design of postmortem studies: the effect size and statistical power

Purpose

The aim is of this study was to show the poor statistical power of postmortem studies. Further, this study aimed to find an estimate of the effect size for postmortem studies in order to show the importance of this parameter. This can be an aid in performing power analysis to determine a minimal sample size.

Methods

GPower was used to perform calculations on sample size, effect size, and statistical power. The minimal significance (α) and statistical power (1 − β) were set at 0.05 and 0.80 respectively. Calculations were performed for two groups (Student’s t-distribution) and multiple groups (one-way ANOVA; F-distribution).

Results

In this study, an average effect size of 0.46 was found (n = 22; SD = 0.30). Using this value to calculate the statistical power of another group of postmortem studies (n = 5) revealed that the average statistical power of these studies was poor (1 − β < 0.80).

Conclusion

The probability of a type-II error in postmortem studies is considerable. In order to enhance statistical power of postmortem studies, power analysis should be performed in which the effect size found in this study can be used as a guideline.

Forensic molecular pathology: its impacts on routine work, education and training

The major role of forensic pathology is the investigation of human death in relevance to social risk management to determine the cause and process of death, especially in violent and unexpected sudden deaths, which involve social and medicolegal issues of ultimate, personal and public concerns. In addition to the identification of victims and biological materials, forensic molecular pathology contributes to general explanation of the human death process and assessment of individual death on the basis of biological molecular evidence, visualizing dynamic functional changes involved in the dying process that cannot be detected by morphology (pathophysiological or molecular biological vital reactions); the genetic background (genomics), dynamics of gene expression (up-/down-regulation: transcriptomics) and vital phenomena, involving activated biological mediators and degenerative products (proteomics) as well as metabolic deterioration (metabolomics), are detected by DNA analysis, relative quantification of mRNA transcripts using real-time reverse transcription-PCR (RT-PCR), and immunohisto-/immunocytochemistry combined with biochemistry, respectively. Thus, forensic molecular pathology involves the application of omic medical sciences to investigate the genetic basis, and cause and process of death at the biological molecular level in the context of forensic pathology, that is, 'advanced molecular autopsy'. These procedures can be incorporated into routine death investigations as well as guidance, education and training programs in forensic pathology for 'dynamic assessment of the cause and process of death' on the basis of autopsy and laboratory data. Postmortem human data can also contribute to understanding patients' critical conditions in clinical management.

S100B immunoreactivity: a new marker of hypoxia-related cardiac damage in newborn piglets

OBJECTIVE

The evaluation of the expression of S100B protein, in the swine heart in an experimental model of hypoxia - reoxygenation.

METHODS

Normocapnic hypoxia was induced in 40 male Landrace/Large White neonatal piglets by decreasing the inspired concentration of oxygen to 6-8%. When animals developed bradycardia or severe hypotension, reoxygenation was initiated. Piglets were allocated in four groups of 10, according to the oxygen concentration they were reoxygenated with: Group 1, 2, 3 and 4 resuscitated with 18%, 21%, 40% and 100% oxygen, respectively. The animals were further classified into 4 groups according with the time required for reoxygenation: group A (<15 min); group B (16-60 min); group C (>60 min); group D (deceased animals).

RESULTS

Immunostaining for S100B protein was detected in 14 out of the 40 heart samples (35%), both inside the cytoplasm of cardiomyocytes and as globular deposits in the interstitial spaces. Significant differences were observed among groups 1-4 regarding S100B expression. Reactivity for S100B in cardiac cells was detected in 50%, 50%, 10% and 33% of animals in groups 1 and 2, 3 and 4, respectively. Marked differences were also observed among groups A-D: 75%, 33%, 12% and 22% of the animals in group 1, 2, 3 and 4, respectively, showed reactivity for S100B in the heart.

CONCLUSIONS

Expression of S100B protein occurred in the heart of some of newborn piglets following severe hypoxia. S100B storage in cardiomyocytes correlates with the different oxygen concentration used during reoxygenation, being higher in piglets reoxygenated with 18% and 21%, and lower in animals reoxygenated with 40% oxygen. Intermediate levels of S100B expression were found in 100% O2-treated animals. The finding of a higher percentage of S100B-immunoreactive hearts in piglets with a fast recovery and the detection of a decreased reactivity in animals with a slow and a very slow recovery clearly indicates S100B protein as an early protective factor with a positive prognostic value in asphyxiated newborn piglets.

S100B and NSE as useful postmortem biochemical markers of traumatic brain injury in autopsy cases

Postmortem analysis of relevant biomarkers might aid in characterizing causes of death and survival times in legal medicine. However, there are still no sufficiently established results of practical postmortem biochemical investigations in cases of traumatic brain injury (TBI). The two biomarkers--S100 protein subunit B (S100B) and neuronal specific enolase (NSE)--could be of special interest. Therefore, the aim of the present study was to investigate changes in their postmortem levels for further determination of brain damage in TBI. In 17 cases of TBI (average age, 58 years) and in 23 controls with different causes of death (average age, 59 years), serum and cerebrospinal fluid (CSF) samples were analyzed with a chemiluminescence immunoassay for marker expression. An increase in serum S100B, as well as a subsequent decrease after survival times>4 days, were detected in TBI cases (p<0.01). CSF NSE values >6,000 ng/mL and CSF S100B levels >10,000 ng/mL seem to indicate a TBI survival time of at least 15 min (p<0.01). It is of particular interest that CSF S100B levels (p<0.01) and serum S100B levels (p<0.05) as well as CSF NSE values (p<0.01) were significantly higher in TBI cases in comparison to the controls, especially when compared with fatal non-head injuries. In conclusion, the present findings emphasize that S100B and NSE are useful markers in postmortem biochemistry in cases of suspected TBI. Further, S100B may be helpful to estimate the survival time of fatal injuries in legal medicine.

S100B protein expression in the heart of deceased individuals by overdose: a new forensic marker?

OBJECTIVE

The evaluation of S100B protein expression in the human heart and its correlation with drug-related death.

METHOD

Left ventricular samples were collected from 74 serial forensic autopsies (15 overdose-related deaths; 59 non-overdose-related deaths) from 2007 to 2010. Tissue sections from each sample were immunostained for S100B protein by a commercial antibody.

RESULTS

The S100B protein was detected in the heart samples of all 15 cases of drug-related deaths; S100B immunoreactivity was mainly observed in the cytoplasm of cardiomyocytes and as globular deposits in the interstitial spaces. No reactivity or weak reactivity was found in the cardiomyocytes of the 59 subjects who died of other causes.

CONCLUSION

Our preliminary data show that the S100B protein accumulates in injured cardiomyocytes during drug-related sudden death. Given the near absence of S100B protein in the heart of subjects who died from causes other than drug overdose, S100B immunopositivity may be used as a new ancillary screening tool for the postmortem diagnosis of overdose-related cardiac death.

Altered brain myelin sheath morphology after rewarming in situ

In this study cerebral ultrastructure was examined in an in vivo rat model, after rewarming from profound hypothermia (15-13 degrees C). Animals held at 37 degrees C served as controls. After rewarming, brains were examined by electron microscope. Micrographs were taken randomly, analyzed anonymously, and quantified by morphometry. Serum analysis of the stress marker S-100beta was carried out in identical groups. The most striking findings in rewarmed animals, when compared to controls, were alterations of myelin sheaths (p<.008) and elevated S-100beta (p<.0001). This indicates that cells in the central nervous system are susceptible to injury in an experimental model of accidental hypothermia and rewarming.

S100B in the cerebrospinal fluid--a marker for glial damage in the rabbit model of pneumococcal meningitis

The rabbit model provides an important experimental setting for the evaluation of antibiotic agents against pneumococcal meningitis. One of the primary targets of this model is the study of neuronal and glial cell damage in bacterial meningitis. The aim of this investigation was to evaluate whether a significant increase of S100B in the cerebrospinal fluid (CSF) as an indicator of white matter damage could be observed in this meningitis model. Seven rabbits were infected intracisternally with S. pneumoniae, and CSF S100B concentrations were examined serially before infection, at 12h, 14h, 17h, 20h, and at 24h after infection. The course of CSF S100B increase and its relation to other parameters of brain tissue destruction and CSF inflammation were measured. Axonal damage was visualized by amyloid precursor protein (APP) immunostaining and demyelination by Luxol Fast Blue/Periodic Acid Schiff (LFB-PAS) stain. In each animal, we observed a distinct rise in S100B concentration in the CSF due to pneumococcal meningitis. We conclude that the CSF concentration of the glial S100B protein can be used as an additional parameter for future interventional studies focusing on glial cell damage in the rabbit model of bacterial meningitis.

Evaluation of postmortem S100B levels in the cerebrospinal fluid with regard to the cause of death in medicolegal autopsy

Previous studies have suggested the usefulness of the postmortem serum S100B level as a marker of the severity of brain damage. In this study, we investigated the S100B level in the cerebrospinal fluid (CSF) in serial autopsy cases (n=216, within 3 days postmortem), including those of blunt injury (n=34: fatal head injury, n=20; others, n=14), sharp instrument injury (n=9), mechanical asphyxiation (n=19), drowning (n=11), fire fatality (n=26), intoxication (n=20), hypothermia (cold exposure, n=16), hyperthermia (heat stroke, n=9), acute cardiac death (n=52) and pneumonia (n=20). The CSF S100B level showed a moderate postmortem time-dependent increase for acute cardiac death (r=0.58, p<0.0001) and asphyxia (r=0.741, p<0.001). In cases of survival time within 48 h, drowning and hypothermia usually showed a lower CSF S100B level (around 500 ng/ml), and the level was higher for delayed head injury death, asphyxia, intoxication, and hyperthermia (around 1500 ng/ml) (p<0.05). In fatal head injury cases, however, CSF S100B did not correlate with the survival time or postmortem interval. A CSF S100B level of >2000 ng/ml in the early postmortem period might be considered a biochemical sign of fatally severe brain damage.

Postmortem serum catecholamine levels in relation to the cause of death

Catecholamines are major humoral factors and neurotransmitters that contribute to various stress responses. However, they have been considered unstable due to agony, terminal medical care and postmortem interference. The present study was a comprehensive investigation of postmortem serum levels of adrenaline (Adr), noradrenaline (Nad) and dopamine (DA) with regard to the cause of death in serial medicolegal autopsy cases (n=542) including fatalities from various traumas and diseases. There was a slight tendency toward postmortem increases of Nad and DA in cardiac blood as well as Adr and Nad in peripheral blood, a slight age-dependent decrease in Adr and DA in right heart blood, and a marked increase in serum DA due to administration during critical medical care. When these factors were taken into consideration, significantly higher cardiac blood levels were observed for Adr and Nad in injury and asphyxiation cases and for Adr in fatal methamphetamine (MA) abuse and other poisoning cases, whereas those levels were lower in fatal hypothermia. Drowning, fire fatality, acute cardiac death and cerebrovascular disease showed intermediate Adr and Nad levels. The DA level was elevated in cases of injury, hyperthermia, MA fatality and other poisoning. Topographical analyses suggested that the major sources of increased serum catecholamines in cases of injury was abdominal viscera including adrenal glands, and that in cases of asphyxiation, drowning, fire fatality, hyperthermia, MA fatality, other poisoning, acute cardiac death and cerebrovascular disease was the extremities in addition to abdominal viscera. However, there was in part a large case-to-case difference in each marker related to individual causes of death. These findings differed markedly from clinical observations and suggest that the postmortem serum catecholamine levels may reflect the magnitude of physical stress responses during the process of death in individual cases.

Immunohistochemical distribution of S-100 protein in the cerebral cortex with regard to the cause of death in forensic autopsy

S-100 protein (S100) is an acidic calcium-binding protein, which is abundantly found in the brain. The aim of the present study was to investigate the immunohistochemical distribution of S100 in the cerebral cortex in forensic autopsy cases with regard to the cause of death and relationship to its serum levels. The cases (n = 286, 3-48 h postmortem) included fatal head injuries (n = 89), acute death from other blunt injuries (n = 29), sharp instrument injuries (n = 20), asphyxiation (n = 29: strangulation/hanging, n = 22; aspiration, n = 7), drownings (n = 22), fire fatalities (n = 68), cerebrovascular diseases (n = 9) and acute myocardial infarction/ischemia (AMI, n = 20). S100-immunopositivity was mainly observed in the gliacytes, in part, in the neurons and myelins. For S100B-immunostaining, the gliacytes and myelins were positive, whereas the neurons were negative. Positivity in astrocytes was dependent on the cause of death, and was significantly lower in acute deaths due to strangulation/hanging and drowning, and mildly low in those due to injuries. Positivity in neurons and myelins was frequently observed in delayed head injury deaths and fire fatalities, showing an inverse relationship with the positivity in astrocytes in head injury cases. For cases of acute death, there was an inverse relationship between S100-positivity in the astrocytes and the serum S100B level. These observations suggest that astrocytes are more rapidly and severely injured than neurons during fatal brain damage, thereby causing an elevation in the serum S100B level.