Ayumi Komatsu

Evaluation of postmortem serum and cerebrospinal fluid levels of thyroid-stimulating hormone with special regard to fatal hypothermia

The aim of the present study was to undertake, during routine forensic work, a comprehensive analysis of the serum and cerebrospinal fluid (CSF) levels of thyroid-stimulating hormone (TSH) and to examine hypophyseal TSH immunopositivity in relation to the cause of death, with particular regard to fatal hypothermia. Medicolegal autopsy cases (n=120; within 48 h postmortem; survival time, <24 h), including cases of blunt injury (n=9), sharp instrument injury (n=8), fire fatality (n=18), mechanical asphyxiation (n=10), drowning (n=21), poisoning (n=6), hypothermia (n=10), and acute ischemic heart disease (n=38), were examined. Serum and CSF TSH concentrations were measured using an electrochemiluminescence immunoassay. TSH immunoreactivity in adenohypophysis was quantitatively analyzed. Serum and CSF TSH levels were significantly lower in cases of hypothermia than in the other groups (p<0.05 and p<0.001, respectively). TSH immunopositivity in adenohypophysis was significantly lower in cases of hypothermia, but exhibited a large case-to-case variation for poisoning. These observations suggest that a decrease in serum and CSF TSH levels in hypothermia is related to hypothalamic adenohypophyseal dysfunction.

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.

Single-stranded DNA as an immunohistochemical marker of neuronal damage in human brain: an analysis of autopsy material with regard to the cause of death.

Single-stranded DNA (ssDNA) is a marker of apoptosis and programmed cell death, which appears prior to DNA fragmentation during delayed neuronal death. The present study investigated the immunohistochemical distribution of ssDNA in the brain to investigate apoptotic neuronal damage with regard to the cause of death in medicolegal autopsy cases (n=305). Neuronal immunopositivity for ssDNA was globally detected in the brain, independent of the age, gender of subjects and postmortem interval, and depended on the cause of death. Higher positivity was typically found in the pallidum for delayed brain injury death and fatal carbon monoxide intoxication, and in the cerebral cortex, pallidum and substantia nigra for drug intoxication. For mechanical asphyxiation, a high positivity was detected in the cerebral cortex and pallidum, while the positivity was low in the substantia nigra. The neuronal ssDNA increased during the survival period within about 24h at each site, depending on the type of brain injury, and in the substantia nigra for other blunt injuries. The neuronal positivity was usually lower for drowning and acute ischemic disease. Topographical analysis of ssDNA-positive neurons may contribute to investigating the cause of brain damage and survival period after a fatal insult.

Evaluation of postmortem calcium and magnesium levels in the pericardial fluid with regard to the cause of death in medicolegal autopsy.

Previous studies have suggested the usefulness of postmortem serum calcium (Ca) and magnesium (Mg) for investigating cause of death. The present study investigated their levels in the pericardial fluid of serial autopsy cases of adults within 48 h postmortem (n=385), including fatalities from blunt injury (n=57), sharp instrument injury (n=9), mechanical asphyxiation (n=28), salt- and freshwater drowning (n=14 and n=61, respectively), fire fatality (n=35), intoxication (n=23), hypothermia (cold exposure, n=12), hyperthermia (heat stroke, n=7), acute cardiac death (ACD, n=86), pneumonia (n=9) and spontaneous cerebral hemorrhage (n=11). The pericardial Ca level was independent of the postmortem interval, showing a value similar to that of the clinical reference range in cases other than saltwater drowning, while the Mg level was higher than the clinical reference range and showed a mild postmortem time-dependent increase. Pericardial Ca was significantly higher for saltwater drowning than other groups, and a lower level was seen for hyperthermia, and some cases of blunt injury and intoxication. The Mg level was also significantly higher for saltwater drowning than the other groups, and showed a higher level for sharp instrument injury, but a lower level for hypothermia. The Mg/Ca ratio was higher for sharp instrument injury and saltwater drowning, but was lower for hypothermia. These findings suggest that postmortem pericardial Ca and Mg can be used to investigate the cause of death, especially for saltwater drowning, hypothermia and hyperthermia.

Analysis of postmortem biochemical findings with regard to the lung weight in drowning

To clarify drowning death, positive evidence for aspiration of the immersion medium and the subsequent fatal mechanism is necessary. This study investigated biochemical findings with regard to lung weight in drowning cases of adults (n=56, >18 years of age, <48 h postmortem: salt water, n=19; fresh water, n=21; brackish water, n=16), using acute cardiac death cases (n=240) as controls. The biochemical markers used in this study were urea nitrogen (UN), sodium (Na), chloride (Cl), calcium (Ca) and magnesium (Mg) in the blood and pericardial fluid (PCF). The left-to-right ratio of cardiac blood UN levels was lower for drowning, showing an inverse correlation to the total lung weight. There was a mild postmortem decrease in serum and PCF Na and Cl levels; however, left cardiac serum and PCF Na, Cl, Ca and Mg levels were higher for saltwater drowning, and left cardiac serum Na and Cl levels were lower for fresh water drowning. Correlation of the left cardiac serum level with lung weight was positive for Na, Cl and Mg in saltwater and brackish water drowning, and was also positive for Ca in saltwater drowning. There was an inverse correlation with lung weight for PCF Na and Cl levels in freshwater drowning. These findings suggest that analyses of serum and pericardial markers in relation to lung weight are useful for evaluating the composition and amount of aspirated medium when investigating drowning death.

Morphological and functional alterations in the adenohypophysis in cases of brain death

In order to examine the function of the adenohypophysis during brain death, levels of adrenocorticotropic hormone (ACTH), growth hormone (GH), and thyroid stimulating hormone (TSH) were investigated during forensic autopsy. Cases examined were those of brain death (n=12; within 24h postmortem; time to cardiac death after cerebral death was diagnosed, approximately 4-25 days), including those in which the cause of death was head injury (subdural hematoma or brain contusion, n=10) and asphyxia (strangulation, n=2). The concentrations of ACTH and TSH were measured by enzyme chemiluminescent immunoassay (ECLIA), and that of GH by radioimmunoassay (RIA). The immunoreactivities of ACTH, GH, and TSH in the adenohypophysis were observed and analyzed with electron microscopy. Morphological studies revealed partial necrosis of the central anterior lobe, but preservation of its periphery. Immunohistochemical staining revealed the appearance of peripheral adenohypophysis with each hormone. Ultrastructural findings for the pituitary and hypothalamus indicated swelling of the mitochondria and dilation of both the smooth endoplasmic reticulum and Golgi apparatus. Furthermore, in most cases, concentrations of the anterior pituitary hormones in the serum and cerebrospinal fluid (CSF) were generally within the clinical reference range. These results indicate that the pituitary is partially preserved after brain death.

Potential risk factors for sudden cardiac death: An analysis of medicolegal autopsy cases

Chronic kidney disease and elevated serum C-reactive protein (CRP) have been suggested as clinical risk factors for cardiac attacks. The present study investigated postmortem blood urea nitrogen (BUN), creatinine (Cr) and CRP levels in the peripheral blood of sudden cardiac death cases. Adult autopsy cases of ischemic heart diseases (n=153, >20 years of age), including acute myocardial infarction (AMI, n=71), recurrent myocardial infarction (RMI, n=47), acute ischemic heart disease without infarction (AIHD, n=27) and chronic ischemic heart disease (CIHD, n=8), were examined and compared with chronic congestive heart disease (CHD, n=24), spontaneous cerebral hemorrhage (SCH, n=17) and mechanical asphyxiation (n=32). BUN was slightly higher for RMI and CHD, although Cr was slightly higher for SCH. CRP was higher for AMI than for AIHD. The correlation between BUN and Cr levels was significant for AMI, AIHD and CHD, but insignificant for RMI and CIHD. Heart weight was larger for all heart diseases and SCH than for asphyxiation, and was larger for RMI and CHD but lower for AIHD and CIHD among them. Body mass index (BMI) was slightly higher for AMI, RMI, AIHD and CHD, remaining within the reference interval in most cases, but was lower for CIHD. These findings suggest different risk factors or etiologies, including active atherosclerosis, latent renal failure, dehydration and cardiac hypertrophy, for sudden deaths due to these heart diseases.

Analyses of cardiac blood cells and serum proteins with regard to cause of death in forensic autopsy cases

To investigate hematological and serum protein profiles of cadaveric heart blood with regard to the cause of death, serial forensic autopsy cases (n=308, >18 years of age, within 48 h postmortem) were examined. Red blood cells (Rbc), hemoglobin (Hb), platelets (Plt), white blood cells (Wbc), total protein (TP) and albumin (Alb) were examined in bilateral cardiac blood. Blood cell counts, collected after turning the bodies at autopsy, approximated to the clinical values. Postmortem changes were not significant for these markers. In non-head blunt injury cases, Rbc counts, Hb, TP and Alb levels in bilateral cardiac blood were lower in subacute deaths (survival time, 1-12 h) than in acute deaths (survival time <1 h). Wbc counts of left cardiac blood were significantly higher for non-head injury than for head injury in subacute deaths. In fire fatality cases, Plt count was markedly higher with an automated hematology analyzer than by using a blood smear test, suggesting Rbc fragmentation caused by deep burns, while increases in Wbc count and decreases in Alb levels were seen for subacute deaths. For asphyxiation, Rbc count, Hb, TP and Alb levels in bilateral cardiac blood were higher than other groups, and TP and Alb levels in the right cardiac blood were higher for hanging than for strangulation. These findings suggest that analyses of blood cells and proteins are useful for investigating the cause of death.

Postmortem serum levels of pulmonary surfactant-associated proteins A and D with regard to the cause of death in medicolegal autopsy

Pulmonary surfactant-associated proteins A and D (SP-A and -D) are tissue-specific components. Previous studies showed an increase in the postmortem serum SP-A level due to acute pulmonary alveolar damage and acute respiratory distress. The present study comparatively investigated serum SP-A and SP-D levels with regard to the cause of death in serial medicolegal autopsy cases (n=679, within 48 h postmortem). SP-A and SP-D levels were usually higher in left cardiac blood than at other sites, independent of postmortem interval. The left-to-right difference was significantly larger for mechanical asphyxiation, drowning, intoxication and spontaneous cerebral hemorrhage. Both SP-A and -D levels in bilateral cardiac blood were significantly higher for drowning and secondary pulmonary damage involving ARDS after traumas, but were lower for hypothermia (cold exposure). SP-A was predominantly elevated in fire fatality and delayed deaths from injury and fires, while pneumonia showed a predominant elevation of SP-D. These findings suggest that comparative analysis of serum SP-D and SP-A is useful for investigating primary or secondary pulmonary alveolar damage in the death process.

Immunohistochemical distribution of chromogranin A in medicolegal autopsy materials

Chromogranin A (CgA) was recently reported as a marker of various stress responses. The aim of this study was to investigate the immunohistochemical distribution of CgA in human tissues in medicolegal autopsy cases as a basis for postmortem investigation of stress responses. The autopsy cases (n=30, within 48 h postmortem) comprised cases of mechanical asphyxia (n=15: strangulation, n=8; hanging, n=7) and acute myocardial infarction/ischemia (AMI, n=15). Routinely formalin-fixed paraffin-embedded tissue sections, including those of the hypothalamus, pituitary gland, cardiac muscle, lungs, liver, kidneys, spleen, skeletal muscle, skin, thyroid gland, submandibular gland, pancreas, and adrenal gland, were stained with polyclonal anti-human CgA antibodies and CgA positivity was quantitatively examined. Localization of CgA immunopositivity was clearly demonstrated in specific cell components in all tissue sections. CgA was mainly observed in the anterior lobe of the pituitary, adrenal medulla, neurons and some gliocytes in the hypothalamus, submandibular gland, follicular epithelial cells and connective tissue in the thyroid gland and pancreatic islet cells. CgA immunopositivity showed no significant difference between mechanical asphyxia and AMI cases. Positivity was slightly higher in adenohypophysis, adrenal medullar, and pancreatic islet cells (approximately 50-80%) than in the thyroid and submandibular glands (approximately 30-60%); however, a large case difference was observed in hypothalamic CgA immunopositivity (0-100%). These findings suggest that hypothalamic CgA immunopositivity can be used as a marker for investigating individual differences in stress responses during the death process. Further investigation of other causes of death is needed.