Post-mortem changes of methomyl in blood

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K18978
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 58040:Forensics medicine-related
• Research Institution: Chiba University
• Principal Investigator: Yamagishi Yoshikazu 千葉大学, 大学院医学研究院, 特任助教 (50834470)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: メソミル / ヘモグロビン / アミノ酸付加体 / カーバメート系殺虫剤 / 酸化反応

Outline of Final Research Achievements

Forensic toxicology is one of the applied research fields of toxicology and necessary to protect people's rights. The accurate determination of blood drug concentration is mandatory to prove death by drug poisoning. However, it has been reported that the fatal drug concentration in blood at autopsy differs from that at the time of death. In this study, methomyl, is specifically bound to Hemoglobin (Hb), which results in the decrease in blood concentration of its free form after death. Methomyl is preferably bound to tryptophan, tyrosine, and valine residues in Hb.Furthermore, it was clarified that the blood concentration at the time of death can be estimated from the amounts of postmortem metabolites produced after death. Moreover, we found that oxime-type carbamate pesticides having an oxime moiety such as aldicarb, butocarboxim, methomyl, oxamyl, and thiofanoxwere decomposed by Hb in a temperature-dependent fashion.

Free Research Field

法中毒学

Academic Significance and Societal Importance of the Research Achievements

法中毒学は、人々の権利を守るために必要な薬学・医学・法学の要素が含まれる、言わば毒性学の応用研究分野の一つであり、薬毒物に関連した死因を究明するために、ご遺体から採取された血液等の検体の薬毒物分析を主要な手法としている。この日々の実務の中から、血中薬物濃度の死後変化というクリニカルクェスチョンを着想し、その解決に向けて研究を実施している。本研究成果であるヘモグロビンが関与した血中死後薬物濃度変化を明らかにしたことにより、血中薬物濃度を正確に把握することが可能になり、薬毒物に関連した死因を究明することに役立つと考えられる。