Immunohistochemical localization of heat shock protein 70 in the human medulla oblongata in forensic autopsies

Systematic Review on Post-Mortem Protein Alterations: Analysis of Experimental Models and Evaluation of Potential Biomarkers of Time of Death

Estimating the post-mortem interval (PMI) is a very complex issue due to numerous variables that may affect the calculation. Several authors have investigated the quantitative and qualitative variations of protein expression on post-mortem biological samples in certain time intervals, both in animals and in humans. However, the literature data are very numerous and often inhomogeneous, with different models, tissues and proteins evaluated, such that the practical application of these methods is limited to date. The aim of this paper was to offer an organic view of the state of the art about post-mortem protein alterations for the calculation of PMI through the analysis of the various experimental models proposed. The purpose was to investigate the validity of some proteins as “molecular clocks” candidates, focusing on the evidence obtained in the early, intermediate and late post-mortem interval. This study demonstrates how the study of post-mortem protein alterations may be useful for estimating the PMI, although there are still technical limits, especially in the experimental models performed on humans. We suggest a protocol to homogenize the study of future experimental models, with a view to the next concrete application of these methods also at the crime scene.

Traumatic Brain Injury: A Forensic Approach: A Literature Review

Traumatic brain injury (TBI) is the principal cause of invalidity and death in the population under 45 years of age worldwide. This mini-review aims to systematize the forensic approach in neuropathological studies, highlighting the proper elements to be noted during external, radiological, autoptical, and histological examinations with particular attention paid to immunohistochemistry and molecular biology. In the light of the results of this mini-review, an accurate forensic approach can be considered mandatory in the examination of suspected TBI with medico-legal importance, in order to gather all the possible evidence to corroborate the diagnosis of a lesion that may have caused, or contributed to, death. From this point of view, only the use of an evidence-based protocol can reach a suitable diagnosis, especially in those cases in which there are other neuropathological conditions (ischemia, neurodegeneration, neuro-inflammation, dementia) that may have played a role in death. This is even more relevant when corpses, in an advanced state of decomposition, are studied, where the radiological, macroscopic and histological analyses fail to give meaningful answers. In these cases, immune-histochemical and molecular biology diagnostics are of fundamental importance and a forensic neuropathologist has to know them. Particularly, MiRNAs are promising biomarkers for TBI both for brain damage identification and for medico-legal aspects, even if further investigations are required to validate the first experimental studies. In the same way, the genetic substrate should be examined during any forensic examination, considering its importance in the outcome of TBI.

Expression patterns of adhesion molecules P-selectin, von Willebrand factor and PECAM-1 in lungs: A comparative study in cases of burn shock and hemorrhagic shock

For comparative examination of the pathological findings in burn shock and hemorrhagic shock, histological and immunohistochemical investigations of the lungs were performed. Histological specimens of 30 cases each were examined by means of immunohistological staining with P-selectin, von Willebrand factor (vWF) and PECAM-1. The results showed statistically significant differences between the two groups. There was strong staining for P-selectin (especially in the lumina of the blood vessels) and vWF (especially in the endothelium of medium-sized blood vessels) in the specimens of burn shock fatalities. In cases of rapid death after exposure to fire the strong expression of adhesion molecules, which are mainly responsible for the initial inflammatory reaction of leucocytes and platelets in burn shock, suggests prompt activation of inflammatory cells in the lung tissue. In cases of hemorrhagic shock, this reaction was much less distinct in the early stages. The same is true of the expression of PECAM-1, which was lower in lungs from burn shock fatalities than in those from hemorrhagic shock fatalities. The low expression of PECAM-1 in burn shock is a clue to the migration/diapedesis of leucocytes into the areas of burn damage. In total, the results of the investigation indicate different pathophysiological processes even in the very early stages of burn shock and hemorrhagic shock.

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.

Expression of heat-shock protein 70 (Hsp70) in the respiratory tract and lungs of fire victims

Immunohistochemical investigation of the respiratory tract and lungs of 63 fire victims revealed a statistically significant enhanced expression of heat-shock protein 70 (Hsp70) in the epiglottis, the trachea, and the main and the peripheral bronchi compared with a control group. In the fire victims, a strong expression of Hsp70 was discernible not only particularly in the vessels but also in seromucous secretory cells, ciliated epithelial cells, smooth muscle cells, and alveolar cells. The results suggest a vital or supravital reaction due to the inhalation of hot fire fumes.

Utilization of lectin-histochemistry in forensic neuropathology: lectin staining provides useful information for postmortem diagnosis in forensic neuropathology

We have investigated the deposition of glycoconjugates in human brain tissue with or without brain disorders. In this review we describe the application of lectin-histochemistry techniques to forensic neuropathology. Lectin staining is able to reveal several kinds of carbohydrate-related depositions in addition to the conventional degenerative changes including senile plaques, neurofibrillary tangles and corpora amylacea. The senile plaques and neurofibrillary tangles were clearly stained by Con A, PSA and GSI lectins, the corpora amylacea which is relevant to repeated brain hypoxia and mitochondrial damage was also easily detected by these and many other kinds of lectins. Amorphous spaces were detected around blood vessels and independently from blood vessels by lectin staining in the white matter from patients with brain disorders or severe edema. The white matter lesions were not considered relevant for forensic pathology, until a large group of cerebral white matter lesions were detected in the elderly with increasing frequency by modern neuro-imaging methods. The spherical deposits were newly detected by lectin staining in the molecular layer of the dentate gyrus of the hippocampal formation chiefly from patients with schizophrenia or cognitive dysfunctions.