Yui Igari
Tohoku University
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Featured researches published by Yui Igari.
Legal Medicine | 2016
Yui Igari; Yoshiyuki Hosokai; Masato Funayama
In determining the time of death in infants based on rectal temperature, the same methods used in adults are generally used. However, whether the methods for adults are suitable for infants is unclear. In this study, we examined the following 3 methods in 20 infant death cases: computer simulation of rectal temperature based on the infinite cylinder model (Ohnos method), computer-based double exponential approximation based on Marshall and Hoares double exponential model with Henssges parameter determination (Henssges method), and computer-based collinear approximation based on extrapolation of the rectal temperature curve (collinear approximation). The interval between the last time the infant was seen alive and the time that he/she was found dead was defined as the death time interval and compared with the estimated time of death. In Ohnos method, 7 cases were within the death time interval, and the average deviation in the other 12 cases was approximately 80 min. The results of both Henssges method and collinear approximation were apparently inferior to the results of Ohnos method. The corrective factor was set within the range of 0.7-1.3 in Henssges method, and a modified program was newly developed to make it possible to change the corrective factors. Modification A, in which the upper limit of the corrective factor range was set as the maximum value in each body weight, produced the best results: 8 cases were within the death time interval, and the average deviation in the other 12 cases was approximately 80min. There was a possibility that the influence of thermal isolation on the actual infants was stronger than that previously shown by Henssge. We conclude that Ohnos method and Modification A are useful for death time estimation in infants. However, it is important to accept the estimated time of death with certain latitude considering other circumstances.
European Journal of Radiology | 2015
Yusuke Kawasumi; Akihito Usui; Yoshiyuki Hosokai; Yui Igari; Tadashi Hosoya; Yoshie Hayashizaki; Haruo Saito; Tadashi Ishibashi; Masato Funayama
OBJECTIVES Infant cases frequently show a diffuse increase in the concentration of lung fields on post-mortem computed tomography (PMCT). However, the lungs often show simply atelectasis at autopsy in the absence of any other abnormal changes. Thus, we retrospectively reviewed the PMCT findings of lungs following sudden infant death and correlated them with the autopsy results. MATERIALS AND METHODS We retrospectively reviewed infant cases (0 year) who had undergone PMCT and a forensic autopsy at our institution between May 2009 and June 2013. Lung opacities were classified according to their type; consolidation, ground-glass opacity and mixed, as well as distribution; bilateral diffuse and areas of sparing. Statistical analysis was performed to assess the relationships among lung opacities, causes of death and resuscitation attempt. RESULTS Thirty infant cases were selected, which included 22 sudden and unexplained deaths and 8 other causes of death. Resuscitation was attempted in 22 of 30 cases. Bilateral diffuse opacities were observed in 21 of the 30 cases. Of the 21 cases, 18 were sudden and unexplained deaths. Areas of sparing were observed in 4 sudden and unexplained deaths and 5 other causes of death. Distribution of opacities was not significantly associated with causes of death or resuscitation attempt. The 21 cases with bilateral diffuse opacities included 6 consolidations (4 sudden and unexplained deaths, 2 other causes of death), 4 ground-glass opacities (3 sudden and unexplained deaths and 1 other) and 11 mixed (11 sudden and unexplained deaths). Types of opacities were not significantly associated with causes of death or resuscitation attempt. CONCLUSION Atelectasis is very common in sudden and unexplained death of infants. Bilateral diffuse mixed opacity was observed only in sudden and unexplained deaths. Bilateral diffuse pure consolidation or ground-glass opacity was also observed in other causes of death.
Legal Medicine | 2013
Masaki Hashiyada; Kiyotaka Usui; Yoshie Hayashizaki; Tadashi Hosoya; Yui Igari; Jun Sakai; Masato Funayama
An elderly person died of uncontrolled bradycardia in a hospital. The doctor had prescribed 1.35 mg of bisoprolol fumarate orally, but a nurse mistakenly gave the patient 10 mg of the drug 9 hours prior to her death. Bisoprolol was detected in her blood by liquid chromatography-mass spectrometry at a concentration of 176 ng/mL. Even if the patient had chronic heart failure, this concentration is double the expected value. This patient was found to have a mutation within cytochrome P2D6, with thymidine substituted for cytosine at position 100 and cytosine for guanine at position 4180, causing proline to serine and threonine to serine amino acid substitutions. This mutation in the intermediate metabolizer allele reportedly reduces enzyme activity by half. However, in addition to the type of cytochrome P450 allelic variant, the amount of enzyme product influences metabolism of this drug. In this case, the high blood concentration of bisoprolol was only partly attributable to an error in prescription; its concentration was inexplicably high.
Acta radiologica short reports | 2013
Akihito Usui; Yusuke Kawasumi; Yoshiyuki Hosokai; Haruo Saito; Yui Igari; Masato Funayama
Gallbladder injuries are extremely rare in blunt trauma, with a reported incidence of <2%. We report an autopsy case of fatal hemorrhagic shock due to intra-abdominal bleeding resulting from complete avulsion of the gallbladder associated with liver cirrhosis. Multiplanar images derived from multislice computed tomography (MSCT) performed as part of pre-autopsy screening showed complete avulsion of the gallbladder without any other associated intra-abdominal injuries, facilitating forensic autopsy planning. In this report, we discuss the role of MSCT in cases of fatal intra-abdominal bleeding caused by avulsion of the gallbladder and discuss the mechanism of this injury.
Journal of Forensic and Legal Medicine | 2017
Yui Igari; Shirushi Takahashi; Akihito Usui; Yusuke Kawasumi; Masato Funayama
A 4-year-old girl who had been treated for asthma since the age of 2 years had a severe coughing fit and died suddenly. The patient had a history of occasional severe coughing fits, and these fits had been worsening in severity during the week before her death. Prior to death, she was taken to a clinician, and thymic hypertrophy was suspected based on chest X-ray findings. The clinician recommended that she visit a general hospital at a later date; however, she died that night. Postmortem radiology and autopsy revealed a large mass in the anterior mediastinum compressing the heart and airway, and no other findings attributable to sudden death were observed. Therefore, we concluded that the patients death was attributable to acute respiratory and cardiac circulatory failure secondary to the pressure induced by the mass. Microscopically, the mass showed a cavernous structure composed of cystically dilated, thin-walled large vessels filled with blood. The final diagnosis was a cavernous hemangioma. Hemangiomas are the most common benign vascular anomalies seen in young children; however, mediastinal hemangiomas are rare and can cause life-threatening complications because of their size and location. Therefore, forensic pathologists should include hemangioma as a differential diagnosis in children with anterior mediastinal masses.
Legal Medicine | 2015
Tomoya Ikeda; Akihito Usui; Takashi Matsumura; Tomomi Aramaki; Tadashi Hosoya; Yui Igari; Tsukasa Ohuchi; Yoshie Hayashizaki; Kiyotaka Usui; Masato Funayama
A man in his 40s was found unconscious on a sofa in a communal residence for people with various disabilities. He appeared to have drunk 800 ml of undiluted citric acid from a commercial plastic bottle. The instructions on the label of the beverage specified that the beverage be diluted 20- to 30-fold before consumption. The patient was admitted to an emergency hospital with severe metabolic acidosis (pH, 6.70; HCO3(-), 3.6 mEq/L) and a low ionized calcium level (0.73 mmol/L). Although ionized calcium and catecholamines were continuously administered intravenously to correct the acidosis, the state of acidemia and low blood pressure did not improve, and he died 20 h later. Citric acid concentrations in the patients serum drawn shortly after treatment in the hospital and from the heart at autopsy were 80.6 mg/ml and 39.8 mg/dl, respectively (normal range: 1.3-2.6 mg/dl). Autopsy revealed black discoloration of the mucosal surface of the esophagus. Microscopically, degenerated epithelium and neutrophilic infiltration in the muscle layer were observed. In daily life, drinking a large amount of concentrated citric acid beverage is rare as a cause of lethal poisoning. However, persons with mental disorders such as dementia may mistakenly drink detergent or concentrated fluids, as in our case. Family members or facility staff in the home or nursing facility must bear in mind that they should not leave such bottles in places where they are easily accessible to mentally handicapped persons.
Legal Medicine | 2014
Yui Igari; Tadashi Hosoya; Yoshie Hayashizaki; Tsukasa Ohuchi; Akihito Usui; Yusuke Kawasumi; Masaki Hashiyada; Masato Funayama
A 3-year-old girl with no particular medical history complained of a stomachache and died on the way to the hospital. The autopsy revealed marked right ventricular hypertrophy and dilation with no other cardiac abnormalities. Microscopically, the pulmonary small arteries showed marked medial hypertrophy and varying degrees of intimal and adventitial thickening. We supposed that the cause of death was attributable to pulmonary arterial hypertension (PAH). PAH is a rare disease that can cause sudden, unexpected death at any age. Forensic pathologists should consider PAH in the differential diagnosis of sudden death.
Forensic Science International | 2014
Yui Igari; Tadashi Hosoya; Yoshie Hayashizaki; Akihito Usui; Yusuke Kawasumi; Kiyotaka Usui; Masato Funayama
A middle-aged female patient with a depressive disorder presented to a mental hospital because of a 2-month worsening history of headache, dizziness, and nausea. The next morning, she was observed to be sleeping, but was then found dead 1h later. Postmortem computed tomography and autopsy revealed a large cyst in the right cerebellar hemisphere, hydrocephalus, and transforaminal herniation. Careful observation revealed an approximately 0.4cm×0.8cm slightly grayish discoloration in the cyst wall that was diagnosed as hemangioblastoma based on its histological features. Finally, we concluded that the cause of death in this case was attributable to the brain stem compression, which was caused by obstructive hydrocephalus secondary to the cystic hemangioblastoma in the cerebellum. The symptoms for 2 months before her death had most likely resulted from increased intracranial pressure. Hemangioblastomas usually appear as nodules in the wall of the cyst, but the tumor in our case looked like just a slightly grayish discoloration. Therefore, cystic lesions in the CNS need to be carefully examined.
Forensic Toxicology | 2014
Kiyotaka Usui; Masaki Hashiyada; Yoshie Hayashizaki; Yui Igari; Tadashi Hosoya; Jun Sakai; Masato Funayama
Materials Science Forum | 1998
T. Takaoka; Haruo Saito; Yui Igari; Isao Kusunoki