Keisuke Mizuo

Experimental rat model for alcohol‐induced osteonecrosis of the femoral head

Alcohol‐induced osteonecrosis of the femoral head (ONFH) is observed in alcohol abusers and patients with alcoholic fatty liver disease. It has been reported that Toll‐like receptor 4 (TLR4) signalling plays a crucial role in the pathogenesis of alcoholic fatty liver disease. We previously reported a corticosteroid‐induced ONFH rat model, and suggested that TLR4 signalling contributes to the pathogenesis of ONFH. Thus, it is thought that the pathogenesis of alcohol‐induced ONFH is probably similar to that of corticosteroid‐induced ONFH. The aim of this study was to develop a new animal model for alcohol‐induced ONFH and to evaluate the relationship between the pro‐inflammatory response via TLRs and the development of ONFH in rats. Male Wistar rats were fed a Lieber–DeCarli liquid diet containing 5% ethanol (experimental group) or dextran (control group) for 1–24 weeks. Histopathological and biochemical analyses were performed. Feeding the ethanol‐containing liquid diet resulted in the development of ONFH with hepatic steatosis, hepatic dysfunction and hyperlipidaemia, whereas feeding the dextran‐containing diet did not cause ONFH. However, we could not recognize any relationship between the pro‐inflammatory response via TLR4 and the development of alcohol‐induced ONFH. Thus in this study we have developed a new rat model for alcohol‐induced ONFH based on the feeding of an ethanol liquid diet. ONFH was observed within seven days from the start of feeding with 5% ethanol‐containing liquid diet. Although this was linked to hepatic steatosis, a TLR4 association was not a feature of this model.

Time-related course of pleural space fluid collection and pulmonary aeration on postmortem computed tomography (PMCT)

Postmortem CT (PMCT) is increasingly used in forensic practice, and knowledge and classification of typical postmortem imaging findings would facilitate the interpretation of PMCT. The goal of this study was to define the time-related course of postmortem chest findings. Twelve cadavers (eight male, four female, 27-81 [mean, 60.0]years) were examined twice by PMCT within an interval of time (4-164 h [mean, 30.8; median, 17.5]). The pleural-space-fluid volume, pulmonary parenchyma volume, decreased aerated lung volume (DLV), %DLV (=DLV/pulmonary parenchyma volume) and chest cavity volume were compared between the first and second PMCT examinations. To evaluate the volume change rate, the rate of increase in pleural space fluid volume (mL/h) and the DLV rate (mL/h) were plotted according to the postmortem period. On the second PMCT, the volume of pleural space fluid (p=0.0469) and %DLV (p=0.0161) were significantly increased. The increase rate of the pleural space fluid increased at approximately 30 h and the volume continued to increase until approximately 40 h after death. The rate of DLV constantly decreased in the early postmortem period. In conclusion, the pleural-space-fluid collection and the DLV increased over different time-related courses in the postmortem period.

New pitfalls of high-density postmortem computed tomography

An 80-year-old female was transferred to the hospital due to a traffic accident. Multiple cranial bone fractures with intracranial hemorrhage and intracranial air were detected. Despite treatment, the patient died after 6h. Twenty-one hours after the patient died, her whole body was scanned by postmortem CT, and a region of high density was detected within the left putamen. The autopsy revealed a cerebral contusion and multiple skull base fractures. Moreover, superabsorbent polymers (SAPs) were found within the left lateral ventricle and adjacent to the putamen, which appeared as a high-density lesion on postmortem CT at the left putamen, where the SAPs were compacted. Both ante- and postmortem conditions should be considered to prevent misdiagnoses based only on postmortem CT.

Weight bearing does not contribute to the development of osteonecrosis of the femoral head

The hip joint is one of the major structures in the human body and the resultant force acting through the hip joint is 300% of body weight. Therefore, weight bearing, as a cause of ischaemia, may contribute to the development of non‐traumatic osteonecrosis of the femoral head (ONFH). However, it remains unclear whether weight bearing is related to the development of non‐traumatic ONFH. Therefore the aim of this study was to clarify the role of weight bearing in the development of non‐traumatic ONFH. Non‐weight‐bearing (NWB) rats were tail suspended to prevent any weight coming to bear on the hindlimbs from day 1 to the time of sacrifice. The weight‐bearing (WB) group rats were also housed individually, although without tail suspension. All rats were injected with lipopolysaccharide and methylprednisolone to promote the development of non‐traumatic ONFH. All animals were sacrificed three weeks after the final methylprednisolone injection. Histopathological analysis was performed. Osteonecrosis of the femoral head was observed not only in the NWB but also in the WB rats; however, no osteonecrosis of the humeral head was observed in either group. We confirmed that non‐traumatic ONFH developed in NWB rats, suggesting that weight bearing does not contribute to the development of non‐traumatic ONFH in rats.

Postmortem computed tomography findings in the thorax – Experimental evaluation

OBJECTIVE Experimental fatal models were prepared to investigate the time-related course of lung changes using postmortem CT (PMCT). This study was approved by our institutional animal ethics committee. MATERIALS AND METHODS Twenty-four NZW rabbits (female 24, 2.30-4.30 (mean 3.10)kg) were divided into 4 fatal groups; drowning, hypothermia, bag suffocation, and Potassium Chloride intravenous (control) group. All individuals were examined by CT (Aquilion CX, Toshiba, Japan) on postmortem time course until detection of putrefaction air. The percent of aerated lung volume (%ALV=100*(ALV/total lung volume)) was measured and the pleural space fluid was investigated by axial imaging. A paired t-test and Bonferroni/Dunn study were employed for statistical evaluation. RESULTS In intra-group analysis, the %ALV showed statistically different periods compared with each pre-image: 4-48 h in control, 1-24h in drowning, 5-6h in hypothermia, and 1-4h in bag suffocation. In inter-group comparison (compared with control group), the %ALV increased in suffocation and decreased in drowning within 12h. The %ALV remained significantly high in hypothermia until 24h. The earliest detection times of pleural space fluid collection were different in each group: control (20 h), drowning (18 h), suffocation (36 h), and hypothermia (95 h). CONCLUSION The lung hypostasis and the appearance of pleural space fluid collection presented differently in individual causes of death and depending on the postmortem time.

TLR4 stimulation and corticosteroid interactively induce osteonecrosis of the femoral head in rat

We previously reported that a toll‐like receptor 4 signaling contributes to the development of osteonecrosis of the femoral head. Also, oxidative stress is suggested to be one of the possible pathogenesis of osteonecrosis of the femoral head. A recent study showed that toll‐like receptor 4 signaling leads to oxidative stress. The aim of the present study was to evaluate whether toll‐like receptor 4 stimulation and subsequent corticosteroid treatment lead to the development of osteonecrosis of the femoral head in rat, and oxidative stress is associated with it. Male Wistar rats were randomly divided into four treatment groups: Saline + Saline, Saline + Methylprednisolone, Lipopolysaccharide + Saline, Lipopolysaccharide + Methylprednisolone. Osteonecrosis of the femoral head at 14 days after the treatment was observed in 1 of 10 Lipopolysaccharide + Saline, and 5 of 10 Lipopolysaccharide + Methylprednisolone treated rats. However, it was not observed at all in the Saline + Saline and Saline + Methylprednisolone treated groups. Glutathione peroxidase activity in the liver at 1 day after the treatment was significantly increased when treated with lipopolysaccharide. However, methylprednisolone treatment reduced the activity. On the other hand, glutathione peroxidase activity in the femur did not change in any intergroup. In conclusion, the present study showed that toll‐like receptor 4 stimulation by lipopolysaccharide administration strengthen incidence of corticosteroid‐induced osteonecrosis of the femoral head, however, concomitant oxidative stress via toll‐like receptor 4 signaling may not contribute to the development of osteonecrosis of the femoral head in rats.

Freezing effect on brain density in postmortem CT

Two 60-year-old males were found at their homes whose bodies had deteriorated due to putrefaction. To prevent worm invasion and minimize deterioration, dry ice was used prior to the autopsy investigation. Prior to autopsy, postmortem CT demonstrated a decreased density in brain parenchyma at the dry-iced side, and autopsy revealed deteriorated brain parenchyma with frozen effect (presented like sherbet). Moreover, the deteriorated cerebral parenchyma maintained their structure and they were evaluated by cutting. When lower CT density presents in postmortem CT, the freezing effect may need to be considered and the physician should evaluate the cadavers postmortem condition to prevent misdiagnoses.

CT-guided percutaneous needle placement in forensic medicine

We have developed a technique of CT-guided needle placement in the destructed human body in forensic practice. A sixty-year-old male was found in a burned car and he was also destructed severely. Although blood was needed for the external examination, it was difficult to approach the vessels because of the severely burned condition of the cadaver. Thus, we attempted to obtain a blood sample from a vessel using a CT-guided technique. Postmortem CT demonstrated the presence of blood-containing vessels in the pelvis. Indeed, CT-guided needle placement had no difficulty with surface markers, table location, or depth measurement from the surface. CT-guide needle placement is a feasible and reliable technique, so that when the tissue/blood sample is at risk of being spoiled, CT-guided needle placement could be a substitute for conventional sampling techniques.

Classification of hemopericardium on postmortem CT

Postmortem CT (PMCT) is increasingly used in forensic practice, and knowledge and classification of typical hemopericardium on PMCT would help to assure correct radiological interpretation. The goal of this study was to evaluate the pericardial and pleural space fluid volumetry, and to evaluate the signs on PMCT pointing to cardiac tamponade as the cause of death, and their pitfalls. Fourteen cadavers (eleven male, three female, 49-87 [mean, 70.9] years) were examined by PMCT. The pericardial volume and pericardial findings with/without pleural space fluid collection were compared with autopsy findings. In addition, the appearance of pericardial lesions on PMCT was documented and compared with the autopsy findings. The respective volumes of pericardial space, and right and left pleural space fluid showed as 172.0-711.0 (mean 368.7) ml, 0-1830.0 (266.1) ml, 0-231.0 (75.2) ml on PMCT, and were 136.0-652.0 (311.1) ml, 0-2100 (299.0) ml, and 0-300.0 (61.3) ml on autopsy. In statistical evaluation, the pericardial space volume was significantly greater on PMCT (p<0.05), but there was no significant difference in pleural space fluid volume. The hemopericardium PMCT showed 3 patterns: double band, single band, and horizontal level, and the former two patterns presented as coagulated blood at autopsy. Single band and horizontal level patterns were thought to result from CPR-related causes and/or postmortem manipulation. In conclusion, double and single band patterns on PMCT were indicative findings of cardiac tamponade. An understanding of the pericardial PMCT appearance and its significance can help to avoid misreading, and is important for making correct radiological interpretation.

Experimental drowning lung images on postmortem CT - Difference between sea water and fresh water

PURPOSE Experimental drowning models were prepared to investigate the time-related course of lung changes using postmortem CT. This study was approved by our institutional animal ethics committee. MATERIALS AND METHODS Fifteen NZW rabbits (female fifteen, 2.6-4.3 (mean 3.3)kg) were divided into 3 groups: fresh water drowning (FRESH), sea water drowning (SEA), and sea water drowning with anterior chest compression (ACC). All individuals were examined by CT (Aquilion CX, Toshiba, Japan) on postmortem time course. The rabbits head was submerged in a water bath for a total of 10 min. In ACC, cardiopulmonary resuscitation was performed for 2 min, additionally. The percentage of aerated lung volumes (%ALV=100 (aerated lung volume/total lung volume)) were statistically evaluated and the lung CT image patterns and pleural fluid appearance time were investigated. RESULTS All lungs had decreased their %ALV within 24h, and there were no statistical differences in and among the 3 groups. After 36 h, %ALV tended to increase in all groups, and only ACC presented a statistical difference between 1h and 36 h (p<0.005). On postmortem lung CT, all lungs presented ground-glass opacity with interstitial thickening spread pattern (100%) and no pattern change during the follow-up period. After presenting pleural space fluid collection, the %ALV tended to increase. CONCLUSION There were no differences among FRESH, SEA, and ACC in %ALV within 24h. Only ground-glass opacity could be detected on postmortem lung CT, experimentally.