Expression of Bcl2l1, Clcf1, IL-28ra and Pias1 in the mouse heart after single and repeated administration of chlorpromazine.

Several chlorpromazine (CPZ)-related deaths have been suspected in forensic autopsies but these are difficult to identify precisely because only low concentrations of CPZ can usually be detected. Patients on CPZ therapy exhibit various cardiovascular diseases, such as arrhythmia and cardiomyopathy. As our previous study revealed that CPZ administration affects the expression of immediate early genes that are induced before any other genes, we expected that CPZ probably affects the heart and, in particular, the gene expression in heart. CPZ changes tumor necrosis factor (TNF) production. After stimulation of TNF, the Janus kinase signal transducer and activator of transcription (JAK-STAT) signaling pathway is activated via TNF receptor (TNF-R), and the pathway participates in the regulation of cellular responses such as apoptosis [1]. We used semi-arrays to determine the JAK-STAT signaling pathway in a mouse cardiomyocyte cell line, HL-1, and real-time quantitative-PCR to determine whether the semi-array data applied in vivo in mouse heart after single and once-daily repeated (1-4weeks) low-dose (0.75mg/kg) or high-dose (7.5mg/kg) CPZ treatment. We found that expression of B cell lymphoma 2 like 1 (Bcl2l1), Cardiotrophin-like cytokine factor 1 (Clcf1), Interleukin-28 receptor alpha (IL-28ra) and Protein inhibitor of activated STAT-1 (Pias1) were significantly changed in vivo. All these genes are associated with apoptosis. The expression level of Bcl2l1 was elevated after a single high-dose CPZ treatment and after 1week of repeated high doses, but returned to baseline from week 2 to week 4. Clcf1 and IL-28ra expression increased from week 2 or 3 after low-dose CPZ treatment. Pias1 also increased from week 2 after low-dose CPZ treatment. Our results indicate that different doses of CPZ can induce distinct patterns of gene expression for preventing the apoptotic progression in mouse cardiomyocytes, suggesting that CPZ can affect cardiomyocytes via the JAK-STAT signaling pathway and that this might lead to cardiomyopathy. In addition, our data may help to clarify the pathophysiology of cardiomyopathy induced by CPZ and to diagnose cardiac sudden death following CPZ treatment.

Expression of C-fos, Fos-B, Fosl-1, Fosl-2, Dusp-1 and C-jun in the mouse heart after single and repeated chlorpromazine administrations.

Many cases of sudden chlorpromazine (Chl)-related deaths have been identified in forensic autopsies. Because Chl concentration detected in such cases is often low, identifying the cause of death can be difficult. Patients on Chl therapy exhibit arrhythmia and cardiomyopathy. Thus, Chl may affect the heart, particularly, gene expression there. Immediate early genes (IEGs) are expressed following stimulation. Using real-time quantitative-PCR, we investigated the mRNA expression of IEGs, including C-fos, Fos-B, Fosl-1, Fosl-2, Dusp-1 and C-jun, in the mouse heart after once-daily high-dose (7.5 mg/kg) or low-dose (0.75 mg/kg) of Chl single and repeated (1-4 weeks) injections. We showed that single high-dose Chl administration induced IEGs except C-jun. This induction was not observed after the repeated administration, and thus; suggested that the transcriptome is altered after repeated administration and tolerance is developed to Chl. Moreover, C-jun expression decreases after repeated administration. These results reflect that C-jun is down-regulated to avoid cardiomyopathy caused by the over stimulation of C-jun. In future, we intend to clarify the Chl-induced IEG cascade via IEGs in the mouse heart. Chl treatment can result in cardiovascular diseases. Investigation of the transcriptome in the heart after repeated Chl administration will aid in elucidating the patho-physiology of Chl-related cardiovascular diseases.

Effect of glucocorticoid on the biosynthesis of growth hormone-containing secretory granules in pituitary cells.

Recent studies have suggested that treatment of glucocorticoid to immature growth hormone (GH)-producing cell line, MtT/S cells, dramatically induced the accumulation of GH-containing secretory granules in the cytosol and differentiated into mature GH-producing cells. However, the molecular mechanism of glucocorticoid-induced GH-containing secretory granule biogenesis in the MtT/S cells remains unknown. In the present study, we found that GH mRNA expression was facilitated by application of glucocorticoid. We artificially increased GH synthesis by transfection of green fluorescent protein-tagged GH (GH-GFP) gene. We found that the artificial elevation of GH expression in the cells did not accumulate the secretory granules in the cytosol, whereas glucocorticoid-induced the biogenesis of granules in GH-GFP-expressing MtT/S cells. We next performed DNA microarray and real-time RT-PCR analysis and found that glucocorticoid significantly altered the expression of membrane trafficking-related protein, syntaxin11 (Syx11). Immunocytochemical analysis further demonstrated that Syx11 positive structures were well colocalized with GH-containing granules in both MtT/S cells and rat anterior pituitary gland. Our findings indicate that glucocorticoid regulate the expression of Syx11 and facilitate the biogenesis and the trafficking of GH-containing granules in the MtT/S cells.

C-fos, fos-B, c-jun and dusp-1 expression in the mouse heart after single and repeated methamphetamine administration.

In forensic autopsy, there are numerous sudden methamphetamine (MA)-related deaths. The concentration of MA in the blood is measured to determine the cause of death in case of MA-related death. As a low concentration of MA is detected in MA-related death cases, it is sometimes difficult to identify to the cause of death. MA abusers often exhibit various cardiovascular diseases. MA induces arrhythmia and morphological change in cultured cardiomyocytes. Therefore, MA might affect heart cells, especially in terms of gene expression. Immediate early genes (IEGs) are expressed before some specific gene expressions following certain stimuli. We investigated the expression of IEGs, including c-fos, fos-B, c-jun and dusp-1 mRNA, in the mouse heart after a once-daily MA injection for 1day, 2 or 4weeks using real-time quantitative PCR. We showed that high-dose (10mg/kg) MA administration on day 1 induced mRNA expression of the four IEGs. In contrast, low-dose (1mg/kg) administration on day 1 did not induce any c-fos expression. These findings were characteristic only of the heart, since c-fos increased after treatment at any dose in the brain, suggesting that the intracellular signal cascade differs in these two organs. Nevertheless, we confirmed the transcriptional tolerance in the heart as well as the brain on chronic administration by investigating IEG expression. We were unable to explain why the expressions of IEGs were similar between both doses of MA after chronic administration, although these differed after the single treatment. Additionally, these results strongly suggest that the transcriptome must be altered after long-term treatment. As MA abuse results in various cardiovascular diseases, investigation of the transcriptome in the heart after chronic MA administration will aid in elucidating the patho-physiology of MA-related cardiovascular disease.

Mitochondrial DNA analysis of Yayoi period human skeletal remains from the Doigahama site.

We analyzed the mitochondrial DNA extracted from 14 human skeletal remains from the Doigahama site in Japan to clarify the genetic structure of the Doigahama Yayoi population and the relationship between burial style and kinship among individuals. The sequence types obtained in this study were compared with those of the modern Japanese, northern Kyushu Yayoi and ancient Chinese populations. We found that the northern Kyushu Yayoi populations belonged to the groups that include most of the modern Japanese population. In contrast, most of the Doigahama Yayoi population belonged to the group that includes a small number of the modern Japanese population. These results suggest that the Doigahama Yayoi population might have contributed less to the formation of the modern Japanese population than the northern Kyushu Yayoi populations. Moreover, when we examined the kinship between individuals in the Doigahama site, we found that the vicinal burial of adult skeletons indicated a maternal kinship, although that of juvenile skeletons did not. The vicinal burial style might have been influenced by many factors, such as paternal lineages, periods and geographical regions, as well as maternal lineages. In addition, skeletons considered to be those of shamans or leaders had the same sequence types. Their crucial social roles may have been inherited through maternal lineage.

Increase in dual specificity phosphatase 1, TGF-beta stimulated gene 22, domain family protein 3 and Luc7 homolog (S. cerevisiae)-like messenger RNA after mechanical asphyxiation in the mouse lung.

We investigated the transcriptome profile of mechanical asphyxia and decapitation at 60 min after death using serial analysis of gene expression. After comparing the results, 11 genes were significantly increased by the mechanical asphyxia treatment in the mouse lung. Of those genes, quantitative real-time PCR revealed that dual specificity phosphatase 1 (Dusp1), TGF-beta stimulated gene 22, domain family protein 3 (TSC22d3) and Luc7 homolog (Saccharomyces cerevisiae)-like (Luc7l) after asphyxia were more significantly increased than those after decapitation. Dusp1 inactivated mitogen activated protein kinase, which functions in cell proliferation. However, the consumption of oxygen had a disadvantageous effect on survival, because tissue or cells were not able to produce energy by internal respiration under the suddenly hypoxic condition following asphyxia. The increased transcripts of Dusp1 following asphyxia suppressed oxygen consumption. TSC22d3 was isolated as a TGF-beta-inducible gene and it is also identified as a glucocorticoid (GC)-induced leucine zipper (GILZ). GC was released from the adrenal gland via HPA axis under the hypoxic condition. Especially in acute suffocation, GC rapidly increased. Therefore, the increase in TSC22d3 may be induced by the increased GC following asphyxia. We were unable to clarify the Luc7l increase, because there are no reports in relation to asphyxia. In addition, GILZ mediates the antiproliferative activity of glucocorticoids. We thought that the increasing TSC22d3 may lead to the suppression of oxygen consumption to avoid wasting energy, as in proliferation, the same as the increase in Dusp1. Our data indicated that the determination of the protein product level in the lung could help in diagnosing asphyxia. In addition, these data may contribute to revealing the patho-physiology of asphyxia and to help diagnose asphyxia, including hanging.

The time-course analysis of gene expression during wound healing in mouse skin.

RNA analysis has been applied to forensic work to determine wound age. We investigated mRNA expression using quantitative RT-PCR of ten genes, including c-fos, fosB, mitogen-activated protein kinase phosphatase-1 (MKP-1), CD14, chemokine (C-C motif) ligand 9 (CCL9), placenta growth factor (PlGF), mast cell protease-5 (MCP-5), growth arrest specific 5 (Gas5), beta-2 microglobulin (B2M) and major urinary protein-1 (MUP-1), in terms of repair response in adult mice. The expression level of c-fos, fosB and MKP-1 transcripts increased drastically, peaked within 1h, and that of the CD14 and CCL9 transcripts peaked from 12 to 24h. An increase in PlGF and MCP-5 mRNA appeared on about day 5. Gas5, B2M and MUP-1 transcripts showed no significant change. Each gene had differentially expressional patterns with time-course. Our result implied that the observation of the 7 genes in wounded skin could serve to aid in the accurate diagnosis of wound age.

Temporal expression of immediate early gene mRNA during the supravital reaction in mouse brain and lung after mechanical asphyxiation.

In forensic pathology, the reactions that occur in the body from somatic death to cell death are commonly termed "supravital reactions". There are many reports of grossly visible and microscopic supravital reactions; however, few papers are available on the supravital reaction concerning gene expression. The aim of this study was to examine the gene expression of immediate early genes (IEGs) including c-fos, fos-B and c-jun in mechanically asphyxiated mouse brain and lung after somatic death and to identify the IEGs expressed at the point of supravital reaction in the brain and lung. Our results confirm that the expression of IEGs changed after death during supravital reaction and that the alterations differed according to the cause of death and the types of organ examined. In addition, IEG expression significantly increased following mechanical asphyxia. These results suggest that there is a specific pattern of gene expression following asphyxia. It is therefore important to identify the specific genes involved, as this may give significant information to aid in the post-mortem diagnosis of strangulation and hanging.

Toluene inhalation induced changes of gene expression in rat brain: fluorescence differential display PCR analysis.

Toluene, an abused substance in Japan, is well known as a neurotoxic chemical and has been shown to have neurobehavioral and electrophysiological effects. We used a fluorescence differential display PCR technique to analyze the genes expressed in the brain by toluene inhalation. We found 20 genes that were differentially expressed by toluene exposure. We confirmed by re-amplified PCR, nucleotide sequence and quantitative real-time PCR that of the 20 cDNAs, only 10 showed reproducible expression patterns by toluene inhalation. Of these genes, four had high homology with known genes (MIDA1, PEBP2 beta, phosphatidylserine synthase 2 and SKAP55) and six fragments were new sequence tags of unknown genes. This result may contribute to reveal the patho-physiological effects of toluene inhalation on rat brain.

Identification of novel genes expressed in hypoxic brain condition by fluorescence differential display.

Fluorescence differential display (FDD) and comparative RT-PCR have been used extensively to detect differentially expressed genes. We investigated hypoxia-induced gene expression in the brain by FDD-PCR and comparative RT-PCR. Mice were anaesthetized after which hypoxia was induced by neck ligation for 1 min or 25 min, then were killed by decapitation, and the brains were dissected either immediately or 30 min after death (Group A1-0, Group A25-0, Group A1-30 and Group A25-30). Control mice without ligation of the neck were killed by decapitation under anaesthesia immediately (Group C-0) or 30 min after death (Group C-30). FDD-PCR, sequence analysis and comparative RT-PCR revealed that mitochondrial thymidine kinase 2, Rab6, selenoprotein T and two novel cDNAs were enhanced in Group A25-0 and Group A25-30 compared with the other groups. In Group A25-30, only RAP2 interacting protein and another novel cDNA were induced. In Group A25-0, one novel gene was detected. These findings were consistent with the results of statistical analysis by ANOVA. No differences of band pattern were observed among Groups A1-0, A1-30, C-0 and C-30. The genes exhibiting altered expression were associated with vital cellular functions, e.g., intracellular signaling and mitochondrial metabolism. In addition, we identified four novel genes, expressed after extended hypoxic conditions in mouse brain with suffocation. These results may contribute to clarify the pathophysiology of asphyxia in the brain and aid in the diagnosis of suffocation.

Homology between ABH-carrier alpha2-seminoglycoprotein and Mac-2 binding protein.

alpha2-seminoglycoprotein (alpha2-SGP), purified from human seminal plasma, is a carrier of glycoprotein for the ABO blood grouping. The alpha2-SGP exists in the secretions of the seminal vesicle and various glands. However, the function of alpha2-SGP is, as yet, unknown. In this study, we determined that two internal amino acid sequences of 8 and 12 residues of alpha2-SGP were Ala-Val-Asp-Thr-Trp-Ser-Trp-Gly and Thr-Leu-Gln-Ala-Leu-Glu-Phe-His-Thr-Val-Pro-Phe. These sequences were completely coincident with the domain 3 of human Mac-2 binding protein (M2BP), which was identified as a tumor-associated antigen. In addition, we also confirmed an alpha2-SGP binding activity to galectin-3 that was one of a ligand for M2BP, and the immunological cross-reactivity between alpha2-SGP and M2BP. These findings strongly suggested that alpha2-SGP was identical with M2BP.

Gene response of mouse skin to pressure injury in the neck region.

We analyzed the gene expression pattern in mouse skin following compression of the neck by fluorescent mRNA differential display (FDD-PCR). RNA was isolated from the skin tissue immediately or 30 min after ligation at the neck for 25 min resulting in death (Group A-0, Group A-30). Control mice underwent no compression of the neck and were killed by decapitation (Group C-0, Group C-30). FDD-PCR and sequence analysis revealed that the faciogenital dysplasia gene (Rho member families) and secreted frizzled related protein 1 (modulator of Wnt networks) were enhanced only in the Group A-30. In addition, common salivary protein 1 and mouse 0 day neonate skin cDNA clone z4631433E12 from the RIKEN full-length enriched library were also induced in Groups A-0 and A-30. These findings were consistent with the results of statistical analysis by ANOVA following quantitative real-time PCR. No differences in band pattern were observed between Group C-0 and Group C-30. Therefore, our findings suggested that the altered expression of genes was associated with signal transduction. The results may contribute to clarifying the pathophysiology of compression of the skin and may be useful in the diagnosis of suffocation.

Effect of hypothermia on postmortem alterations in MAP2 immunostaining in the human hippocampus.

Ischemic neuronal injury induce degradation of microtubule-associated protein 2 (MAP2). In addition to ischemia, postmortem brains show alterations in MAP2 immunoreactivity in the hippocampus, suggesting that the factors inducing cytoskeletal disruption in postmortem brain are similar to those in ischemic brains. Hypothermia reduces the severity of ischemic injury including disruption of MAP2 in the hippocampus. However, whether hypothermia reduces postmortem changes of MAP2 was not clear. In this study, we evaluated the effect of hypothermia on postmortem degradation of MAP2 in the human hippocampus at various postmortem intervals using immunohistochemistry. In postmortem brains without hypothermia (the normothermic group), the locus of MAP2 immunoreactivity moved from the dendrites to the cell bodies prior to becoming undetectable with increasing postmortem interval, particularly in the CA1-subiculum region. On the other hand, the change in MAP2 immunoreactivity was remarkably attenuated in brains of death from cold (the hypothermic group). The present study demonstrated that MAP2 disruption is remarkable in the CA1-subiculum region of autopsied brains and that hypothermia reduces the postmortem change of MAP2, as observed in ischemic brain. Therefore, immunostaining of MAP2 in the hippocampus could be used to diagnose hypothermia.

Effect of hypothermia on postmortem alterations in MAP2 immunostaining in the human hippocampus.

Ischemic neuronal injury induce degradation of microtubule-associated protein 2 (MAP2). In addition to ischemia, postmortem brains show alterations in MAP2 immunoreactivity in the hippocampus, suggesting that the factors inducing cytoskeletal disruption in postmortem brain are similar to those in ischemic brains. Hypothermia reduces the severity of ischemic injury including disruption of MAP2 in the hippocampus. However, whether hypothermia reduces postmortem changes of MAP2 was not clear. In this study, we evaluated the effect of hypothermia on postmortem degradation of MAP2 in the human hippocampus at various postmortem intervals using immunohistochemistry. In postmortem brains without hypothermia (the normothermic group), the locus of MAP2 immunoreactivity moved from the dendrites to the cell bodies prior to becoming undetectable with increasing postmortem interval, particularly in the CA1-subiculum region. On the other hand, the change in MAP2 immunoreactivity was remarkably attenuated in brains of death from cold (the hypothermic group). The present study demonstrated that MAP2 disruption is remarkable in the CA1-subiculum region of autopsied brains and that hypothermia reduces the postmortem change of MAP2, as observed in ischemic brain. Therefore, immunostaining of MAP2 in the hippocampus could be used to diagnose hypothermia.

An adult autopsy case of acute encephalopathy associated with influenza A virus.

On a cold winter morning, a 35-year-old male was unexpectedly found dead and therefore autopsied. Macro- and microscopically, the lungs were demonstrated bronchopneumonia. On the surface of brain, small blood vessels were slightly congested. Microscopically, brain edema was also observed, and proliferation of lymphocytes was observed around the capillary vessels of the hippocampus. These findings suggested a viral infection of the cerebrum. We conducted an immunohistochemical study with antibody against influenza virus. Influenza A virus antigen was detected in both the lungs and brain. Therefore, findings were compatible with influenza A encephalopathy. Even when serological inspection is not performed, it is useful to inspect localization of the virus antigen immunohistochemically. We considered that it is necessary to perform pathological examination for influenza encephalopathy in sudden death cases when influenza is epidemic.

The expression of '150-kDa oxygen regulated protein (ORP-150)' in human brain and its relationship with duration time until death.

The expression of oxygen regulated protein 150-kDa (ORP-150) was strongly induced in human brain under the hypoxic conditions. We examined the expression of ORP-150 in the brain samples, and discussed its significance in forensic practice. The cerebral cortexes of 31 cases (asphyxia: 9 cases, hypothermia: 4, exsanguinations: 5, CO intoxication (CO): 6, sudden cardiac death (SCD): 7) were used for this study. Each tissue section was incubated with anti-ORP-150 polyclonal antibody and the number of ORP-150 positive cells were counted. In the multiple linear regression method, the estimated regression coefficient of ORP-150 on age was significant (P=0.039) thus, we could find that the ORP-150 expression level depended on age. Using analysis of covariance, we compared the means of ORP-150, LSMEAN, which means hypothetic average value excluding influence of age, for each cause of death. The LSMEAN+/-SE was 84.74+/-9.03 in hypothermia, 57.52+/-6.34 in asphyxia, 46.68+/-6.70 in CO, 24.84+/-8.05 in exsanguinations, and 16.24+/-7.35 in SCD. As a result of the analysis, the LSMEAN of the ORP-150 expression level was related to the cause of death. There might be differences in the duration of brain ischemia before death. For example, SCD is presumed to be instant death, while brain ischemia continues for several minutes in asphyxia, CO and exsanguinations, and for several hours in hypothermia cases. Therefore, the immunohistochemical and morphometrical analysis of ORP-150 in the brain may be very useful to determine the duration of brain ischemia before death in forensic autopsy cases.

Immunohistochemical study on the induction of heme oxygenase-1 by traumatic brain injury.

We investigated the dynamics of the induction of heme oxygenase-1 (HO-1) in the human brain after death caused by traumatic brain injury (TBI). HO-1 was found to stain neurons and microglia/macrophages in cases with TBI, whereas no positive staining except for a few round cells in the arachnoidal space was observed in control cases. In a case with 7h survival, a considerable number of HO-1 positive neurons and microglia were observed. The number of HO-1 positive cells and level of HO-1 staining gradually increased up to 24h survival. Although HO-1 positive neurons were seldom observed in cases with more than 7-day survival, HO-1 positive microglia were still observed even in cases with 5-month survival. The results indicate that HO-1 may be induced by TBI in human cases, and suggest that prolonged HO-1 induction in microglia might reflect its role in protecting those cells from secondary damage including oxidative stress.

The expression of a novel stress protein '150-kDa oxygen regulated protein' in sudden infant death.

The oxygen regulated protein 150-kDa (ORP-150) is only induced in hypoxic conditions. We performed an immunohistochemical and morphometrical study on the expression of ORP-150 in the brains of sudden infant death (SID) victims. The cerebral cortexes of 18 infants were used for this study. Each tissue section was incubated with anti-ORP-150 polyclonal antibodies and the number of ORP-150 positive cells was counted. In the cluster analysis, the 18 cases were classified into three groups (A-C groups). Group A was composed of six sudden infant death syndrome (SIDS) cases and its mean value of ORP-150 positive cells was 66.75+/-3.44, Group B (six severe respiratory infectious disease such as pneumonia and bronchitis including sepsis): 39.50+/-2.52 and Group C (five SIDS and one severe respiratory infectious disease): 16.00+/-2.92, respectively. These results might reflect chronic hypoxic condition before death, because ORP-150 is only induced when a hypoxic condition exist, but not acute hypoxia. And chronic hypoxic state is likely to be antecedent to SIDS. Therefore, immunohistochemical analysis of OPR-150 in the brain of SID cases may be very useful to differentiate between SIDS and acute asphyxia.

The expression of excitatory amino acid transporter 2 in traumatic brain injury.

It is well recognized that glutamate is the major excitatory neurotransmitter, which is removed from the synaptic cleft by excitatory amino acid transporter 2 (EAAT2) located on the perisynaptic astrocytes and that neuronal death has been associated with an increased extracellular glutamate concentration. In this study, we have immunohistochemically demonstrated the expression of EAAT2 protein in the human brain after traumatic brain injury (TBI). The EAAT2 expression patterns can be divided into three types: continuous and highly extensive staining (E); continuous but sporadic staining (M); and sporadic pattern staining (S). In six of the nine short survival cases studied (1 h to 1 day), continuous and highly extensive staining for EAAT2 (E type) was observed in the ipsilateral cerebral cortex. On the other hand, we were able to demonstrate weak staining (S and M types) in 5 of the 7 long survival cases (> or =1 day) and in 12 of the 14 very short survival cases (<1 h) studied. Similar findings were obtained in the contralateral cerebral cortex and also in the ipsilateral hippocampus. In addition, positive staining for glial fibrillary acidic protein was detected around the cerebral contusion, but the EAAT2-positive expression was not observed in the same region for all of the six short and long survival cases (> or =1 h) after TBI. These findings clearly showed the differences in EAAT2 expression in the cerebral cortex according to the survival time and severity of cerebral contusion after TBI. Therefore, we emphasized that EAAT2 might play an important role in contributing to extracellular glutamate concentrations and secondary brain injury after TBI.

Induction of apolipoprotein E after traumatic brain injury in forensic autopsy cases.

We investigated the dynamics of the induction of apolipoprotein E (apoE) in the human brain after death caused by traumatic brain injury (TBI). A striking difference in apoE immunoreactivity in the traumatised cortical hemisphere compared with the contralateral non-traumatised hemisphere was observed. ApoE was detected within the neurons of the traumatised cortical hemisphere in cases surviving only about 2 h, as well as in those surviving for extended periods. In contrast, no apoE staining within the neurons was seen in the contralateral cortical hemisphere. ApoE staining within astrocytes was faint in both traumatised and contralateral hemispheres of cases surviving only 2 h. However, staining was intense in the traumatised hemispheres in short as well as long surviving cases, even those surviving more than 1 month. ApoE immunoreactivity was also observed in areas adjacent to capillaries and surrounding the neuropil of the injured hemisphere. These observations corroborated the idea of a prolonged induction of apoE within the neurons and also in the extracellular matrix after TBI. Furthermore, the possibility is suggested that the alteration of apoE distribution may contribute to a cerebroprotective mechanism immediately after TBI.