Satoru Miyaishi

Typing of Y chromosome single nucleotide polymorphisms in a Japanese population by a multiplexed single nucleotide primer extension reaction

We have developed a new method for typing single nucleotide polymorphisms (SNPs) on the human Y chromosome based on a multiplexed single nucleotide primer extension. This method has the advantage that several SNPs are typed rapidly and simultaneously. We examined 15 different SNP loci on Y chromosome, M9, M105, M122, M125, M128, M130, SRY465, IMS-JST006241, IMS-JST006841, IMS-JST002611, IMS-JST003305, IMS-JST008425, IMS-JST021354, IMS-JST021355 and IMS-JST055457, in 159 Japanese males. From the typing results of these 15 loci, we found 13 haplotypes. Gene diversity for each locus ranged from 0.025 to 0.486 and the haplotype diversity was estimated to be 0.838. This method could be readily applied for personal identification and paternity testing.

Sudden unexpected death due to rupture of the stomach

We report a case of sudden unexpected death due to rupture of the stomach. A 49-year-old man was found dead in a public lavatory. Autopsy findings revealed two rupture wounds measuring 14 cm and 6 cm located in the fundus of stomach at the side of the greater curvature despite of any superficial injury. The deceased had an ulcer in the lesser curvature of stomach, and dilation in this area was expected to be impaired. Under this condition, excessive over-eating resulting in over-extension of the stomach wall at the greater curvature was speculated to have caused stomach rupture.

Water-restraint stress enhances methamphetamine-induced cardiotoxicity

Methamphetamine (MAP) and stress both cause a variety of cardiovascular problems. Stress also increases stimulant drug-seeking or drug-taking behavior by both humans and animals. In addition to the physiological effects on circulation, metabolism, and excretion, stress affects subjects responses to stimulant drugs such as MAP. However, the mechanisms underlying the drug-stress interactions remain unknown. In the present study, we assessed the effects of stress on myocardial responses to MAP in mice. Mice were injected with MAP (30mg/kg) immediately before exposure to water-restraint stress (WRS), which has often been used as a stressor in animal experiments. The combination of MAP with WRS produced a significant increase (p<0.01) in the leakage of proteins specific to myocardial damage and the levels of cytokines IL-6, TNF-α, and IL-10. The histological findings indicated the possibility that a combination of MAP with WRS induced cardiac myocytolysis. We also examined the expression of heat shock proteins (Hsps), which have cardioprotective effects. Administration of MAP alone significantly stimulated the RNA expressions of Hsp32, 60, 70, and 90 and the protein Hsp70 in cardiac muscles, whereas the expressions due to WRS or MAP plus WRS were not increased. These results reveal the fact that exposure to WRS depresses the induction of Hsps, in particular Hsp70, due to MAP injection, following to enhance MAP-induced myocardial damage. We believe that interactions between MAP and severe stress, including environmental temperature, affect the induction of Hsps, following to susceptibility of hosts to cardiotoxicity due to the stimulant drug.

Identification of human skeletal muscle from a tissue fragment by detection of human myoglobin using a double-sandwich ELISA

A method for identifying human skeletal muscle by detection of human myoglobin using a double-sandwich ELISA was developed. When an extract was prepared from 0.1 g skeletal muscle homogenized with 10 ml PBS, this method was able to detect human myoglobin in extracts diluted 10(4)-fold. There was no difference in the detection limit between individuals or sites of origin of skeletal muscles. Species specificity was good and no cross reaction occurred with skeletal muscle from other animals except the gorilla. Our method could also discriminate between skeletal muscle and other organs or tissues except the heart. Human myoglobin could be detected in skeletal muscles under the following conditions: putrefied at room temperature for 5 months, dried at room temperature for 11 months, heated at 100 degrees C for 72 h and immersed in fresh water at room temperature for 6 days. Two practical cases to which this method was applied are presented.

Massive pulmonary embolization with cerebral tissue due to gunshot wound to the head.

Autopsy findings in a 22-year-old man who received a gunshot wound to the head and died at the scene are presented. Massive white-grey emboli were found in the pulmonary arteries, and these were identified as cerebral cortical or glial tissue by histological examination. It was thought that the momentary severe increase of intracranial pressure and simultaneous rupture of the superior sagittal sinus due to the kinetic energy of the bullet had caused the lacerated cerebral tissue to enter the blood stream.

Histopathological changes of the hypophysis in malnutrition in elderly subjects

Major objectives in forensic gerontology are physical and mental disorders during aging. which can be caused by various factors involving nutrition and stress, often accompanied by dysfunction in the neuroendocrine systems including the hypophysis. The objective of the present study was to investigate the histopathological changes in the adenohypophysis in elderly subjects using autopsy materials. Hypophyses with a scaphoid shape (group S: 16 males and 4 females: mean age. 78.6 years) and a normal one (group C: 30 males and 20 females: mean age. 65.2 years) were compared. Incidence of the scaphoid-shaped hypophysis mildly increased with age, being 17% in the elderly over 65 years of age. The weight of the pituitary gland in group S (0.42 ± 0.1 g) was lower than that of group C (0.65 ± 0.2 g). The degree of fibrosis was higher in group S (31.6% ± 5.4%) than in group C (18.3% ± 6.3%). lmmunohistochemical staining showed no significant differences in the proportion of the ACTH cells and the TSH cells between the two groups (p>0.05). However, there was an increase in the proportion of gonadotrophs. prolactin cells, and S-100-containing cells in group S and a decrease in that of GH cells (p<0.05). These findings may be associated with reduced anabolic, gonadal and hepatic functions due to malnutrition.

Sudden infant death due to Lactococcal infective endocarditis

Infective endocarditis (IE) of infants is rare, most of which occur associated with congenital heart disease or its cardiac surgery. We experienced a case of sudden death of a four-month-old male infant without congenital heart disease. It was elucidated by postmortem examination that the dead had suffered severe IE, which led him to death. In the microbiological genetic analysis using histological section, the pathogen causing inflammation in the present case was identified as Lactococcus lactis subspecies, although Staphylococci have been reported to be common and important one. Previously reported infectious diseases by Lactococcus lactis subspecies were all adult cases and this is the first report of an infantile death due to Lactococcal IE according to our knowledge. Any fatal disease may be included in sudden death cases targeted for forensic autopsy, even if it is rare. It is expected for forensic pathologists that they note such case and share each experience among themselves and other medical fields to develop a strategy for prevention.

Child deaths with persistent neglected experiences from medico-legal documents in Japan

Few studies have examined the actual conditions of fatal neglect in Japan. The aims of this study were to investigate persistent neglect among child fatalities using medico‐legal documents, and to describe the characteristics of the socio‐familial background and biological data.

Factors that prolong the ‘postmortem interval until finding’ (PMI-f) among community-dwelling elderly individuals in Japan: analysis of registration data

Objectives To clarify the factors affecting ‘postmortem interval until finding’ (PMI-f) among elderly unexpected death cases. Design Cross-sectional study. Setting All area of Yamagata prefecture in Japan. Participants Entering subjects were 5675 elderly cases with age of ≥65 years selected from all 9002 cases of unexpected death from 2002 to 2007 in Yamagata prefecture between 2002 and 2007. Our final study subjects consisted of 3387 cases sampled with several criteria to assess the factors to prolong PMI-f. Primary outcome measures The outcome was the postmortem interval until finding (PMI-f) as the time from death until finding the body which we defined in this study. Results ‘Living alone’ showed the highest adjusted HR (3.73, 95% CI 3.37 to 4.13), also ‘unnatural death’ (1.50, 1.28 to 1.75), ‘found at own home’ (1.37, 1.22 to 1.55) and ‘younger subjects’ (0.99, 0.98 to 0.99). In the model including interactions with the household situation, we found ‘male subjects living alone’ and ‘female subjects living with family’ tended to be found later. Conclusions PMI-f is an effective outcome for quantitative analyses of risk of bodies left. To prevent the elderly dead bodies left for long time, it is necessary to keep regular home-based contact with elderly individuals living alone.

Polymorphism of the D12S391 microsatellite in a Japanese population sample

Using the polymerase chain reaction (PCR), we studied the short tandem repeat (STR) polymorphism observed at the D12S391 locus. In 350 Japanese examined, 14 different alleles ranging from 209 bp to 261 bp were detected. Allele 18 (221 bp) showed the highest frequency at 0.30. Observed and expected values of respective genotypes satisfied the Hardy-Weinberg equilibrium (chi 2 = 24.08, P = 0.24, df = 20). In addition, 18 additional sequence structures (suballeles), were detected in this study. Within the suballeles, sequence variants, in which the initial repeat of (AGAT) was replaced with (AGGT), was found in five samples. It was found that the analysis of single-strand conformation polymorphism (SSCP) before sequence analysis was useful for distinguishing these suballeles.