[Application of immunohistochemistry for forensic pathological diagnosis: finding of human brain in forensic autopsy]

We researched the application of immunohistochemistry for the purpose of establishing forensic pathological diagnoses. In the present study, we examined the induction and expression of heat shock protein (HSP), oxygen regulated protein (ORP), inducible nitric oxide synthase (iNOS), excitatory amino acid transporter 2 (EAAT2) and apolipoprotein E (apo E) in the human brain using forensic autopsy cases as our subjects. Hypoxic/ischemic brain damage. In cases of longer survival and with a history of hypoxic attacks, the proteins HSP and ORP were found in the parieto-occipital lobe and hippocampus. And we are able to observe a weak stain for EAAT2 in almost all asphyxia deaths. Traumatic brain injury (TBI). In traumatic brain injury (TBI), the prolonged induction of iNOS was demonstrated in the neutrophils, microglia/macrophage, and vascular smooth muscle cells in the traumatized brain. Apo E was identified with neurons in the traumatized cortical hemisphere from only a two-hour survival case to long survival cases. To the contrary, there was no positive apo E staining in the contralateral cortical hemisphere at all. In one one-hour survival case, a weak stain for EAAT2 was observed, but intensive expression of EAAT2 was observed from brief to one-day survival cases. Sudden infant death (SID). Numerous ferritin-positive cells were observed in the brain in the cases of pneumonia or myocarditis that we examined. To the contrary, the numbers of ferritin-positive cells were obviously decreased in the cases of sudden infant death syndrome (SIDS). The transferrin-positive cells were in an inverse proportion to the ferritin positive cells in each SIDS case. Also, numerous ORP-150 positive cells were observed in the brain in cases of pneumonia and the SIDS group. In forensic practice, immunohistochemical investigation of these proteins can be a great value for diagnosing not only the cause of death but also the pathophysiological changes and the victims past history.