Faculty of Medicine School of Medicine Department of Social Medicine, Legal Medicine


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  • Life Science / Forensics medicine


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  • Conventional diatom testing using strong acid: Notable false-positive results caused by an underestimated contamination source (blind spot)

    Kakizaki E., Shinkawa N., Sonoda A., Yukawa N.

    Forensic Science International   330   111131   2022.1

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Forensic Science International  

    Low rates of diatom positivity in the closed organs of drowning victims present challenges for diatom testing. High positivity rates in closed organs of non-drowning victims also raise an important issue. These contradictory findings were common in diatom testing studies undertaken during the 1960–80 s, but the reasons remained unclear. In the present study, we identified one of the most important factors associated with false-positive results in diatom testing using strong acid. One to 290 false-positive diatoms were found in reused Kjeldahl flasks that were thoroughly washed after the first diatom testing and kept free of tissue before the second testing. False-positive results occurred in 11 of 20 cases when more than approximately 10,000 diatoms were present in digested tissue or water samples. Reused flasks were found to contain many common diatoms (<30 µm), including Cocconeis, Cymbella, Diatoma, Gomphonema, Navicula, and Nitzschia, in agreement with reports of diatoms identified in closed organs. Surprisingly, such false-positive results occurred even at the sixth diatom testing using the same flasks kept free of tissues in each analysis. In contrast, no diatoms were detected in any reagent or associated with other glassware. Thus, reuse of Kjeldahl flasks can readily cause false-positive results that cannot be completely prevented by cleaning the flasks using alkali detergents, as evidenced by detection of diatoms even after six tests. We assume that diatoms causing false-positive results are partially melted by heating and fixed onto the flask's inner surface glass, as the diatom frustule consists primarily of SiO2, similar to glass. Adherent diatoms are then released from the glass by re-heating at the next diatom testing. These results also suggest that the number of diatoms remaining in a flask can increase steadily as a result of repeated reuse for analysis of lung or water samples. In contrast, in analyses using only new flasks, only one or two diatoms were found in 4 of 20 kidney, 2 of 12 liver, and 2 of 8 blood samples from 20 drowning victims. It is difficult to determine whether such diatoms are actually carried via the blood circulation, as contamination with a few diatoms can occur during autopsy procedures and diatom testing. In conclusion, only new (unused) Kjeldahl flasks should be used for diatom testing with strong acid digestion. Moreover, these data suggest that the number and frequency of diatoms present in closed organs of drowning victims may be much lower than previously thought.

    DOI: 10.1016/j.forsciint.2021.111131



  • Adult Dismembered Body With Myositis Ossificans: Evidence for Physical Abuse in an Autopsy Case Report

    Shinkawa N., Kakizaki E., Sonoda A., Yukawa N.

    The American journal of forensic medicine and pathology   42 ( 1 )   73 - 76   2021.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:The American journal of forensic medicine and pathology  

    ABSTRACT: A case involving an adult dismembered body with myositis ossificans (MO) is described. A woman in her 20s was found dead in her cohabitants' room. The body had dismembered into 15 pieces. Computed tomography showed ectopic mineralization in the bilateral upper arms and thighs. On autopsy, the skin and soft tissue were in the process of adipocere formation. Darkened areas that appeared to be subcutaneous hemorrhage were distributed on the face, left chest, and back. Bilateral upper arms and thighs showed organized granulations adherent to underlying bone. Microscopically, these organized lesions represented mature bone tissue in the periphery, cartilage tissue in the middle layer, and fibrotic tissue in the central part. These were typical findings of MO. Myositis ossificans and subcutaneous hemorrhage seemed to be evidence of antemortem repetitive physical abuse. In cases of dismemberment, the absence of organs and parts of the body provide limitations to determining cause of death. In forensic fields, adult autopsy cases involving MO are rare. This is an unusual case in which MO revealed antemortem physical abuse despite dismemberment of the body.

    DOI: 10.1097/PAF.0000000000000628



  • "black ring-shaped burn" in button battery ingestion is not a burn - Comparison with charring using spectral CT

    Shinkawa N., Meiri T., Kakizaki E., Sonoda A., Yukawa N.

    British Journal of Radiology   94 ( 1128 )   20210271   2021

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:British Journal of Radiology  

    Objectives: To compare "black ring-shaped burn"(BRSB) and charring using spectral computed tomography (CT). Methods: Spectral CT was performed using chicken pectoralis minor muscle, processed in three ways and unprocessed as a control: A) BRSB generated by bringing the negative pole surface of a 3 V button battery (BB) into contact with the muscle; b) BRSB caused by a 1.5 V BB; c) charring caused by broiling; and d) control. Attenuation values were compared between BRSB and charring. Muscles were formalin-fixed and stained with Perls' Prussian blue. Results: Attenuation values from polychromatic 120-kVp images were significantly higher for BRSBs than for charring. In the spectral Hounsfield unit curve, attenuation values for BRSBs were higher for lower energy. Histopathologically, BRSBs stained positively with Perls' Prussian blue. Conclusions: This study using spectral CT revealed that BRSB contains metal and confirmed the presence of Fe3+ histopathologically. BRSB differs from charring due to burns.

    DOI: 10.1259/bjr.20210271



  • 小児のボタン電池誤飲を防ぐために – 低電圧1.5Vのボタン電池でも組織傷害性アルカリは生成される(第2報).

    新川慶明,中野 敦,柿崎英二,林 里采,園田 愛,湯川修弘.

    日本医事新報   2020.11

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  • Acceleration effect of the forensic luminol reaction induced by visible light irradiation of whole human blood aqueous solutions. Reviewed

    Hayashi S, Kakizaki E, Sonoda A, Shinkawa N, Shiragami T, Yukawa N.

    Forensic Science International   2019.4

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    Publishing type:Research paper (scientific journal)  

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Grant-in-Aid for Scientific Research 【 display / non-display

  • 水死体の鑑別診断に簡便・迅速に対応するための新規スクリーニング検査法の開発

    2018 - 2021.03

    科学研究費補助金  挑戦的萌芽研究