Publications by authors named "Masayuki Nata"

An autopsy case of sudden death due to pulmonary arterial hypertension (PAH) in a 5-year-old boy whose cause of death was not determined during autopsy, but was later determined by postmortem examination, is presented. The boy developed convulsions that subsequently stopped, but remained unconscious. He was transported to hospital by ambulance, but died soon after.

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Acute gastric volvulus resulting in abdominal compartment syndrome was determined to be the cause of death in a 4-year-old girl who presented with abdominal distension. At about 1AM on the day of her death, she was brought to our emergency medical center. Physical examination and plain abdominal X-ray revealed pronounced gastric dilatation.

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There is a close relationship between the central nervous system activity and bone metabolism. Therefore, methamphetamine (METH), which stimulates the central nervous system, is expected to affect bone turnover. The aim of this study was to investigate the role of METH in bone metabolism.

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Methamphetamine (METH) abuse continues to be a worldwide problem, damaging the myocardial tissues, as well as the brains of individual users. In addition, stressors that increase drug cravings also contribute to cardiovascular diseases. The aim of the present study was to examine the myocardial effects of METH, including METH‑stress interactions and particularly, the effect of METH RNA expression in the heart.

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A 77-year-old female in the hospital was found tachycardic and hypothermic by a nurse, and the patient's respiration subsequently ceased. Forensic autopsy revealed an intracranial cystic tumor that would have compressed the brainstem. On microscopic examination, the tumor was diagnosed as an Antoni A schwannoma growth, and recent multiple intratumoral hemorrhages in the intracranial schwannoma were observed, suggesting the sudden enlargement of the intracranial schwannoma due to intratumoral hemorrhaging.

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The aim of this study was to molecular-biologically investigate the interaction between heat exposure and pulmonary fat embolization in regards to the development of acute lung injury (ALI). Ten-week-old Wistar male rats were divided into four groups: (1) oleic acid injected into caudal vein after heat exposure, (2) oleic acid injected without heat exposure, (3) soybean oil injected after heat exposure, and (4) soybean oil injected without heat exposure, and then mRNA expression of eight inflammatory mediators related to ALI/acute respiratory distress syndrome (ARDS) and heat shock protein 70 (Hsp70) in lung was determined 1h after the injection. mRNA expression of interleukin 1 beta (Il1b), tumor necrosis factor alpha (Tnfa), vascular endothelial growth factor A (Vegfa), transforming growth factor beta 1 (Tgfb1) and Hsp70 was significantly increased by heat exposure, while that of Il1b, interleukin 6 (Il6), Tnfa, macrophage inflammatory protein 2 (Mip2) and granulocyte macrophage-colony stimulating factor (Gm-csf) was significantly elevated by the injection of oleic acid.

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The aim of this study was to investigate the difference between the pharmacokinetics of haloperidol in normal rats and in rats with fatty liver disease. A therapeutic dosage (0.1 mg/kg) and a toxic dose (15 mg/kg) of haloperidol were administrated to normal 9-week-old male rats or those with severe fatty liver disease, and the blood concentration of haloperidol was determined 15 min, 1, 2, and 3 h following haloperidol administration.

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The aim of this study was to investigate direct effects of heat exposure on the heart molecular-biologically and pathohistologically, using rats exposed to high temperatures. The mRNA expression of natriuretic peptide type A (Nppa), natriuretic peptide type B (Nppb), actin alpha 1 skeletal muscle (Acta1), myosin heavy polypeptide 6 cardiac muscle alpha (Myh6) and myosin heavy polypeptide 7 cardiac muscle alpha (Myh7) was determined in the hearts of the rats. Whereas the expression of Nppa and Nppb rapidly increased immediately after the heat exposure, the expression of Acta1 was gradually reduced, which indicated cardiac overload.

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Article Synopsis
  • A 6-year-old boy was found dead with severe vomiting, and a postmortem CT scan showed an epidural haematoma in his brain.
  • An autopsy revealed that the haematoma was caused by a laceration in a blood vessel, which happened about a week before his death, leading to a gradual and then sudden increase in blood accumulation in the brain.
  • Ultimately, the cause of death was determined to be choking on vomit, which was a result of increased pressure in the brain due to the expanding haematoma.
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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 subject's responses to stimulant drugs such as MAP.

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Abuse of many substances is one of the serious problems in Japan, and we often encounter an autopsy case where the individual died in association with the administration of them. Although their intoxication is mainly diagnosed on the basis of their serum concentrations, it is difficult to diagnose as their poisoning when their concentrations are less than lethal level. Moreover, the mechanism of death induced by them is still unclear.

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In order to investigate the interaction in the heart between the administration of methamphetamine (MAP) and restraint of the body following it, we administrated MAP intraperitoneally to mice and restrained them, and then determined the level of mRNA expression of 22 genes in the heart using quantitative RT-PCR method. The mRNA expressions of Nfkbiz, Nr4a1 and Dusp1 changed significantly after the administration of MAP, suggesting the induction of an inflammatory condition such as damage to the myocardium. Moreover, the serum concentrations of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1 beta and IL-6 were significantly increased by the administration of MAP.

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Exposure to stress activates the hypothalamus-pituitary-adrenal (HPA) axis, which is followed by an increase in production of its end product, corticosterone, considered to be the most important glucocorticoid (GC) in rodents. Glucocorticoid receptor (GR) signaling has been suggested as a potential mechanism responsible for the pathogenesis of many clinical disorders. Here, we investigated the involvement of the GR polymorphism in stress response.

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Stress-induced gastric mucosal injury is a common clinical entity. On the other hand, abuse of methamphetamine (MA) represents a growing social problem. MA users are frequently in stressful situations.

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Primary Sjögren syndrome (SjS) has a comparatively good prognosis except when it is complicated by non-Hodgkin's lymphoma. We performed an autopsy on a young female patient with primary SjS who had died suddenly during a meal, and we discuss the relationship between primary SjS and the cause of death. Eosinophilic change of the cardiomyocytes and severe arteriolosclerosis were observed within the myocardium.

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The aim of this study was to examine whether the detection of pulmonary fat embolization is valid as a significant indicator of heat exposure in forensic autopsies. In 54 cases where there was no evidence of fracture, burn or pancreatitis, 25 cases (46.3%) showed pulmonary fat embolization, the degree of which was pathohistologically classified as slight in all cases.

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