Biomedical subjects

Yoshimasa Kanawaku

Publications and source records attributed to Yoshimasa Kanawaku.

7 recordsLinked to original sources

PubMed2006

Computer simulation for postmortem cooling processes in the outer ear.

INTRODUCTION: A simulation using a computer model was undertaken to investigate postmortem cooling patterns in the outer ear. METHODS: Cooling patterns were analyzed using a 3-dimensional head model built from brain CT images of a volunteer. The simulation was verified with a case subject under constant environmental conditions to obtain an appropriate heat transmission coefficient. RESULTS: The cooling pattern of the head model agreed with that of the case subject when the heat transmission coefficient was 6W/m(2) degrees C, and it could be approximated to a single exponential curve. DISCUSSION: This is the first simulative study to show the postmortem cooling pattern of the head of an adult human. Our head model will prove useful to predict the cooling patterns of not only the outer ear but also of the entirety of the head.

Body Temperature↗

PubMed2006

Automatic continuous monitoring of rectal temperature using a button-type thermo data logger.

We performed automatic continuous monitoring of rectal and ambient temperatures using button-type thermo data loggers in autopsy cases. The button-type data loggers have a battery-powered memory that can record 2048 temperature readings. The measurement intervals and other initial settings are determined by computer software, and the measurements were taken at 5-min intervals for this study. At autopsy, the data loggers were retrieved and recorded temperature graphs were produced. This study obtained three representative cases. In one case, the button-type data logger was not discharged regardless of how the body was moved after the device was inserted into the rectum. In two other cases, the cooling curves of the rectal temperature readings clearly followed changes in ambient cooling conditions. The advantages of the tested devices are their small size (diameter, 17.4 mm; thickness, 5.9 mm) and ease of insertion into the rectum, requiring no special skills. Many temperature-based algorithms to determine time of death have been developed, and as a matter of course, the temperature values must be accurate and reliable. Ensuring the validity of each temperature reading requires continuous data from an internal data logger. A button-type data logger is ideal for this purpose.

Body Temperature↗

PubMed2006

Effects of rounding errors on postmortem temperature measurements caused by thermometer resolution.

Beginning 7 h after death, a datalogger was used to measure the temperature in the external auditory canal of an adult male body placed in a refrigerated room. The sequence of measured values approximated a single exponential function with a correlation coefficient of 0.998475. This suggests that the starting time of body cooling in the refrigerated room under constant temperature can be calculated with less error using any two data points recorded by the datalogger. However, the results of such calculations varied widely and longer postmortem intervals demonstrated greater calculation errors. Periodic errors also appeared. Mathematical simulations showed that this variation was caused by rounding errors, which represent the difference between the thermometer readings and the true temperature. The resolution of the thermometer was 0.1 degrees C, a normal specification; however, even this led to noticeable rounding errors. Therefore, significant errors may influence postmortem interval estimations using other body temperatures. When body temperatures are used to determine the time of death, a method that minimizes rounding errors should be considered.

Body Temperature↗

PubMed2006

Sudden infant death: lingual thyroglossal duct cyst versus environmental factors.

An 8-month-old female baby was found collapsed in the prone position 30 min after being positioned under soft-bedding. She was taken to the emergency room with cardiopulmonary arrest. Her heartbeat was recovered after resuscitation and continued for 20 h under artificial respiration, at which point the child died. At autopsy, the child showed no significant pathological abnormalities apart from a thyroglossal duct cyst of 2.0 cm diameter, therefore, it seemed that the cyst, which was close to the epiglottis, had caused asphyxia through airways occlusion. However, the child had shown no respiratory problems before death, and the risk of airway occlusion as a result of lingual cysts is more likely in a supine rather than a prone position. A small amount of evidence suggested that the child died as a result of suffocation from being covered by soft-bedding, which could have caused fatal asphyxia; it is also possible that a hypoxic state induced by airway obstruction might have been enhanced by being covered with bedding. It seemed reasonable to assume that death was caused by a combination of the lingual thyroglossal duct cysts and asphyxia caused by being covered in bedding, though the main factor appeared to be the large cyst.

Airway Obstruction↗

PubMed2005

12 Y-chromosomal STR haplotypes in Japanese.

Haplotypes and allele frequencies of 12 Y-STRs were examined in a population sample of 381 Japanese male volunteers. A total of 315 haplotypes were identified, of which 288 haplotypes were unique, and 18, three, three, two, one and one were found in two, three, four, five, eight and 18 individuals, respectively. Total gene diversity was 0.997.

Asian People↗

PubMed2005

Concentrations of toluene in the body killed by an injury to the head shortly after ingesting thinner.

An autopsy was conducted on a male showing leather-like skin damage, revealing the cause of death to be an injury to the head. Thinner was found scattered around the scene of death, and stomach and intestine contents smelled strongly of solvent. Toxicological analysis was conducted to determine whether or not the solvent was of a lethal level. Using gas chromatography, peaks of toluene, xylene, and ethylbenzene were detected in the blood and gastric contents. No toluene was detected in the urine, and therefore it was concluded that the decedent died of a severe head injury shortly after solvent ingestion. In the literature, toluene concentrations in blood and lung samples were determined as both fatal and non-fatal but clear differences in the fatality of toluene in solid organ samples, namely, the brain, liver and kidneys were shown. The brain is especially useful in postmortem analysis. In this case, the concentration of toluene in the brain was 20.0 microl/g, which was considered as a non-lethal level.

Benzene Derivatives↗

PubMed2005

The relationship of a high level of serum beta-hydroxybutyrate to cause of death.

To examine the state of ketoacidosis in relation to the cause of death, three kinds of ketone bodies (acetoacetate, beta-hydroxybutyrate and acetone) were measured in postmortem serum. Of 100 autopsy cases, 22 had ketone body increasing pathophysiological conditions, overlapped in some cases, namely a poorly-nourished state (10 cases), alcoholic fatty liver damage (10), diabetes (5) and infectious disease (5). Of the 3, 11, 7 and 15 cases in which the beta-hydroxybutyrate concentration was greater than 10,000, 1000-10,000, 500-1000 and 200-500 micromol/l, 3 (100%), 8 (73%), 3 (43%) and 5 (33%), respectively, had one or more pathophysiological conditions that usually produce ketone bodies. Of the 64 cases in which the beta-hydroxybutyrate concentrations were less than 200 micromol/l, only 3 (5%) had some of these conditions. Cases showing high levels of ketone bodies tended to have pathophysiological states that can produce them, although the level of beta-hydroxybutyrate and these states did not show parallel relationships. When autopsy findings fail to explain the cause of death, a diagnosis as death caused by ketoacidosis would be reasonable if the serum beta-hydroxybutyrate level is over 1000 micromol/l and the body has pathophysiological conditions that tend to increase ketone bodies.

3-Hydroxybutyric Acid↗