Biomedical subjects

Jun Kanetake

Publications and source records attributed to Jun Kanetake.

10 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

The relationship between bedding and face-down death in infancy: mathematical analysis of a respiratory simulation system using an infant mannequin to assess gas diffusibility in bedding.

Rebreathing is a model for the relationship between a prone sleeping position and sudden infant death syndrome. This study used a mechanical simulation model to establish the relationship between types of bedding and rebreathing potential for an infant placed prone (face down) at different postnatal ages. The infant mannequin was connected to a respirator set to deliver physiologically appropriate combinations of tidal volume (V(T)) and respiratory rates (RR) across a range of postnatal ages (0-18 months). Before measurements were made, CO(2) flow was regulated to 5+/-0.1% of end-tidal PCO(2) (EtCO(2)). After the model was placed in a prone position, any increase in the fractional concentration of inspired CO(2) (FiCO(2)) was measured. FiCO(2) increased immediately and rapidly, and reached a maximum value within a few minutes. The maximum FiCO(2) ranged from under 2% to over 10%, depending on the bedding. FiCO(2) was also affected by V(T) and RR. This model is not applicable to actual infants because of the large tissue stores of CO(2) in infants; however, it is useful for evaluation of gas diffusibility of bedding and will simplify the investigation of sleeping environments when a baby is found dead with its face covered by soft bedding. In general, the higher the FiCO(2), the greater the rebreathing potential. Theoretically, considering the paucity of body stores of O(2), changes in FiO(2) would be affected not by changes in FiCO(2), but by CO(2) production and gas movement around the infant's face. The rapid decrease of FiO(2) is approximated at the inverse of the FiCO(2) timecourse, suggesting the significance of not only CO(2) accumulation but also O(2) deprivation in the potential space around the baby's face.

Bedding and Linens↗

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

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↗

PubMed2004

A parent-of-origin detectable polymorphism in the hypermethylated region upstream of the human H19 gene.

The H19 gene is a paternally imprinted gene located on chromosome 11p15.5. In this study the H19FR haplotype polymorphism including three SNPs upstream of the H19 gene was investigated. Six genotypes derived from three alleles were detected in the Japanese population by means of PCR and subsequent constant denaturing gel electrophoresis. Based on the methylation status of the genomic DNA from blood samples, selective detection of the parental allele for H19FR was examined by using two types of enzyme, the methylation-sensitive restriction enzymes HpaII or HhaI and McrBC. Genomic DNA digested by either HpaII or HhaI, revealed a single band derived from the paternal allele, as a result of cleavage of unmethylated recognition sites on the maternal allele. On the contrary, the use of McrBC, which can digest a methylated paternal sequence, resulted in exclusively amplifying the maternal allele. This method could be one of the useful techniques for discriminating the parental origin of alleles.

Alleles↗

PubMed2003

A case of acute gasoline intoxication at the scene of washing a petrol tank.

We encountered a case of acute gasoline intoxication at the scene of washing the inner wall of a petrol tank. The decedent was a 50-year-old male, who was the supervisor. Two young workers wearing mask respirators began to wash the inner wall of the gasoline tank under poor ventilation. About 1 h later, because one of the workers lost consciousness, the supervisor entered the tank, without a mask respirator, to rescue the worker. However, the supervisor immediately fainted, and died 26 h after the accident. In the autopsy, blisters were observed on the skin of the face, neck, anterior chest, upper extremities, and back. The heart contained hemolyzed blood. Histologically, hemorrhagic pulmonary edema, pneumonia, and proximal tubular necrosis were found. In the toxicological analyzes, toluene, xylene, and trimethylbenzene were detected in the blood, brain, and gastric contents. Toluene concentrations in the blood and brain were 0.3 mug/ml and 3.7 mug/g, respectively. Since pathological findings were consistent with the reported findings concerning gasoline intoxication, and constituents of gasoline were in the body, death was attributed to acute gasoline intoxication. It was considered that sufficient ventilation and proper use of a mask respirator were essential for this kind of work.

Accidents, Occupational↗

PubMed2003

Evaluation of rebreathing potential on bedding for infant use.

BACKGROUND: Rebreathing is thought to be associated with sudden infant death syndrome (SIDS). The aim of the present study was to evaluate the rebreathing potential of different types of Japanese infant bedding. METHODS: The rebreathing potential of various combinations of infant bedding was measured using a mechanically simulated breathing model. The types of bedding included five types of mattresses, four types of o-nesyo sheets (waterproof sheets) and a towel. The half-life of the expiratory CO2 concentration, t1/2-value was calculated as the index of the rebreathing potential. The softness of the bedding was also measured. RESULTS: There was a moderate proportional correlation between the t1/2-value and the softness (correlation coefficient = 0.509). When a new hard infant mattress was used, the t1/2-values were 13.6-14.1 s, and when o-nesyo sheet was added, the values were 14.1-16.2 s. When other mattresses were used with the o-nesyo sheet, the values were 14.1-19.2 s. Adding a towel onto the bedding, the t1/2-value (18.5-22.3 s) was prolonged without exception. CONCLUSION: It is difficult to estimate the rebreathing potential of the bedding on the basis its appearance or its softness. All infants should be placed on appropriate bedding in case they turn to a prone-sleeping position. Our recommendations to avoid rebreathing are as follows: (i) a new hard mattress specifically designed for babies should be used; (ii) a towel should not be used; (iii) an o-nesyo sheet may be used with a new hard infant mattress if necessary.

Bedding and Linens↗