Shogo Tokudome

Analysis of Maxillofacial Injuries of Vehicle Passengers Involved in Frontal Collisions

PURPOSE To clarify the incidence and mechanisms of maxillofacial injuries sustained by motor vehicle passengers, in-depth data from the Institute for Traffic Accident Research and Data Analysis, Japan, were retrospectively analyzed. MATERIALS AND METHODS From the Institute for Traffic Accident Research and Data Analysis in-depth data for 1993 through 2005, data were collected for 226 individuals with maxillofacial injuries who were adult passengers involved in frontal motor vehicle collisions. The accident information, a subjects medical data, and anatomic Injury Severity Scores were examined. RESULTS The median Injury Severity Score was 2, and the mean equivalent barrier speed of the vehicles was 35.2 ± 13.0 km/hour. The most common maxillofacial injuries were lacerations (46.7%), followed by abrasions (41.9%), fractures (14.0%), and dental injuries (5.7%). Maxillofacial fractures occurred more often in unrestrained drivers without airbag deployment (18.4%) and less often in restrained drivers with airbag deployment (4.3%). The incidences of fractures caused by impacts with areas other than the steering wheel were markedly decreased using any safety device (35.5% to 0%). CONCLUSION Combined use of seat belts and airbags by occupants decreases fractures compared with completely unrestrained occupants. Furthermore, wearing a seat belt prevents the free flight of drivers within a vehicle and contact with the interior of a vehicle (other than the steering wheel). Although the anatomic Injury Severity Score of maxillofacial injuries was relatively low, because these injuries are also associated with socioeconomic costs, the correct use of safety devices and further development of more effective injury prevention systems are needed.

Effects of seat belts worn by pregnant drivers during low-impact collisions

OBJECTIVE The aim of this study was to understand the injury mechanisms of pregnant drivers and associated fetal outcomes. STUDY DESIGN Frontal and rear impact tests using a dummy representing the anthropometry of a pregnant woman were conducted. RESULTS In frontal impact tests without a seat belt, abdominal pressure peaked at the point where the dummy contacted the steering wheel. Rear impact tests without a seat belt showed that the dummy moved forward because of rebound and contacted the steering wheel, which was avoided when a seat belt was worn. CONCLUSION Wearing a seat belt reduces abdominal pressure or prevents contact with the steering wheel during collisions.

Analysis of seating position and anthropometric parameters of pregnant Japanese drivers.

Objective. An anthropometric study was performed to understand the quantitative characteristics of the seating posture of Japanese pregnant drivers. Methods. Twenty pregnant women with a mean gestation of 31.4 ± 1.9 weeks and 20 age-matched, non-pregnant women provided written informed consent to participate in this study. A mid-sized, sedan-type passenger vehicle was used for measurement. The subjects, wearing light clothing, sat in the drivers seat of the vehicle and fastened the seatbelt after adjusting the seat to their usual driving posture. Longitudinal displacement of the slide adjuster and the reclining angle of the seat back were measured, relative to the reference position. Seating posture was investigated by measuring the coordinates of the anthropometric datum points of the drivers (head, shoulder, hip joint, knee joint, and the clearance between the steering wheel and the upper torso). Results. The mean horizontal clearance between the lower rim of the steering wheel and the abdomen of the pregnant women was 146 ± 56 mm, significantly smaller than that of the non-pregnant women (251 ± 51 mm), due to the protrusion of the abdomen. There was no significant difference in seat adjustment position between the two groups. The height of the pregnant women and the horizontal distance from the lower rim of the steering wheel to the abdomen showed a moderate linear correlation in the pregnant group (R 2 = 0.56). Conclusions. Compared to previous studies, the differences of longitudinal distance were found between American and Japanese subjects without significant differences of body heights, due to the difference of body weights and abdominal circumferences. This is the first report to analyze the seating position and anthropometric parameters of pregnant drivers in an Asian population.

Sudden Death While Driving a Four-Wheeled Vehicle: An Autopsy Analysis

We retrospectively analysed forensic autopsies to resolve various issues associated with sudden natural death while driving. We collected information about the medical history, drug treatment, anthropometry and body mass index (BMI) of 34 individuals who suddenly died of natural causes while driving four-wheeled vehicles. The reasons for driving, details of the vehicle, type of collision, perspective of vehicle behaviour and types of avoidance manoeuvres were also examined. The injury severity score (ISS), the Abbreviated Injury Scale (AIS) and the degree of cardiomegaly of the driver were determined from autopsy findings. The dominant cause of death was ischemic heart disease, which closely agreed with previous findings. However, forensic signs indicated that only 20.6% of deceased drivers had attempted avoidance manoeuvres such as braking or steering before the fatal accident, which contradicts previous findings.

CD2-mediated regulation of peripheral CD4+ CD25+ regulatory T-cell apoptosis accompanied by down-regulation of Bim

Extensive studies on CD4+ CD25+ regulatory T (Treg) cells suggest that they are important in regulating immune responses. However, mechanisms of peripheral Treg cell homeostasis are unknown. We found that stromal cells isolated from secondary lymphoid organs such as spleen and lymph nodes could support the survival of Treg cells. This was dependent on CD2 engagement and a direct interaction between Treg cells and stromal cells. In the presence of stromal cells, Bim, a pro‐apoptotic factor, was partially decreased in Treg cells. This effect could be inhibited by anti‐CD2 blocking antibodies, indicating that stimulation through CD2 on Treg cells regulates Bim expression, which may be relevant to Treg cell apoptosis. Therefore, Treg cell interactions with stromal cells through CD2 may be essential for Treg cell survival. Surprisingly, the expression of CD2 ligands on stromal cells was not detected. Hence, it is not clear how CD2 on Treg cells contributes to a direct interaction with the stromal cells and participates in survival support for Treg cells. Taken together, CD2 stimuli were mandatory for Treg cell survival with reduced Bim expression, but CD2 may not function as a direct receptor for molecules on stromal cells.

Assessing injury severity in bicyclists involved in traffic accidents to more effectively prevent fatal bicycle injuries in Japan

The objective of this study was to clarify the relationship between injury severity in bicyclists involved in traffic accidents and patient outcome or type of vehicle involved in order to propose effective measures to prevent fatal bicycle injuries. Hospital records were reviewed for all patients from 2007 to 2010 who had been involved in a traffic accident while riding a bicycle and were subsequently transferred to the Shock Trauma Center of Dokkyo Medical University Koshigaya Hospital. Patient outcomes and type of vehicle that caused the injury were examined. The mechanism of injury, Abbreviated Injury Scale (AIS) score, and Injury Severity Score (ISS) of the patient were determined. A total of 115 patients’ records were reviewed. The mean patient age was 47.1 ± 27.4 years. The average ISS was 23.9, with an average maximum AIS (MAIS) score of 3.7. The ISS, MAIS score, head AIS score, and chest AIS score were well correlated with patient outcome. The head AIS score was significantly higher in patients who had died (mean of 4.4); however, the ISS, MAIS score, and head AIS score did not differ significantly according to the type of vehicle involved in the accident. The mean head AIS scores were as high as 2.4 or more for accidents involving any type of vehicle. This study provides useful information for forensic pathologists who suspect head injuries in bicyclists involved in traffic accidents. To effectively reduce bicyclist fatalities from traffic accidents, helmet use should be required for all bicyclists.

Analysis of child-vehicle collision injuries by vehicle type

PURPOSE This study aimed to determine the severity of injuries to each body region of child pedestrians struck by different types of vehicles. METHODS We collected in-depth data from the Institute for Traffic Accident Research and Data Analysis on pedestrians younger than 13 years with any bodily injuries from collisions with vehicles between 1993 and 2004. RESULTS Sixty-eight patients with a mean age of 6.9 ± 2.4 years were included in the study. In collisions, vehicles caused higher Abbreviated Injury Scale (AIS) scores than those from impact with the road. Injury Severity Score and AIS values were higher with one-box or sports utility vehicles compared with those in sedan vehicles, but the differences were not statistically significant. The mean AIS score of head injuries was significantly higher with one-box or sports utility vehicles than that with sedans (1.6 ± 2.1 vs 0.5 ± 1.1, P < .05). The mean AIS score of the lower extremities was significantly higher with sedans than that with one-box or sports utility vehicles (1.2 ± 1.0 vs 0.5 ± 0.9, P < .05). CONCLUSIONS The type and severity of injuries in child-car collisions vary by type of vehicle and pedestrian kinematics.

Differential gene expression of multiple chondroitin sulfate modification enzymes among neural stem cells, neurons and astrocytes.

Chondroitin sulfate/dermatan sulfate (CS/DS) polysaccharides have been reported to play a crucial role in the proliferation and maintenance of neural stem cells (NSCs). However, little is known about the structural changes and functional role of CS/DS chains in the differentiation of NSCs. Western blots of NSCs, neurons and astrocytes in culture, with three CS-polysaccharide antibodies of different specificities, revealed marked differences in CS structure among the three cell types. To confirm this finding, we measured gene expression levels of CS sulfotransferases and C5-epimerase in these cell types, as these are responsible for producing the high structural diversity of CS/DS. Expressions of chondroitin 4-O-sulfotransferase, chondroitin 6-O-sulfotransferase, and N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase mRNAs were low in cultures of differentiated neural cells, such as neurons and astrocytes, in comparison to NSCs. In contrast, expressions of uronyl 2-O-sulfotransferase and C5-epimerase mRNAs were higher in the differentiated neural cells than NSCs. Thus, we first provide evidence to support the hypothesis that CS/DS undergoes structural changes during NSC differentiation. The structural changes in CS/DS may be implicated in the regulation of NSC differentiation through interactions with growth/neurotrophic factors and cytokines.

AUTOPSY CASES OF SUDDEN UNEXPECTED INFANT DEATHS EXAMINED AT THE TOKYO MEDICAL EXAMINER'S OFFICE, 1964-1993

The medical examination system in Japan covers only four regions (Yokohama, Osaka, Kobe and the 23 wards in Tokyo). In almost all other regions, it is difficult to perform reliable epidemiologic studies. This report presents a chronological analysis of sudden infant deaths, including sudden infant death syndrome, over 30 years (1964-93) in the 23 Tokyo wards.

Problems on the diagnosis of sudden infant death syndrome.

Various autopsy cases of sudden unexpected death (SUD) in infancy were examined at the Tokyo Medical Examiners Office between 1985 and 1994. More than half of the SUD were diagnosed as sudden infant death syndrome (SIDS), but a number of other causes, such as mechanical asphyxia, were also diagnosed. SIDS is diagnosed by autopsy, but there are no clear diagnostic criteria differentiating SIDS from other causes of SUD. SUD is diagnosed as SIDS when other causes are excluded, but it is difficult to distinguish between SIDS and mechanical asphyxia. There was not a large difference in autopsy findings, or in death scene or statistical data, between SIDS and non‐SIDS cases. In their estimation of the diagnostic ratio of SIDS to other causes of death, medical examiners might be divided into three groups: ‘SIDS tolerationist’ examiners think that SUD should be positively diagnosed as SIDS, insofar as another cause of death is not proved clearly. A second group of examiners might be regarded as ‘SIDS exclusionist’; these consider microscopic findings or peculiar death scenes as important contributing factors leading to death. The third group represents a middle stance somewhere between these two. We thought that (forensic) pathologists as well as medical examiners in Japan might have differing stances on SIDS diagnosis. The statistical analysis of SIDS in certain research areas may be affected by the diagnostic ‘preference’ of pathologists belonging to a certain institute.