Study on the establishment of a method for estimating postmortem time by precise analysis of stomach contents using mass spectrometry

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K21153
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0908:Society medicine, nursing, and related fields
• Research Institution: Osaka Medical and Pharmaceutical University
• Principal Investigator: Mori Kazuya 大阪医科薬科大学, 医学部, 助教 (60796738)
• Project Period (FY): 2021-08-30 – 2024-03-31
• Keywords: 法医学 / 死後経過時間

Outline of Final Research Achievements

We focused on stomach contents with the aim of establishing a new indicator for estimating time since death.
In this study, we used mass spectrometry to identify primary metabolic products such as amino acids that appear during the digestive decomposition process of food contained in stomach contents, and to confirm changes in their behavior over time.
We decided to use cooked rice grains as the food to be analyzed, which is the staple food of the Japanese people and is often found in stomach contents during forensic autopsies. When cooked rice grains were reacted with artificial gastric juice, statistically significant differences were found in the expression levels of some amino acids over time. Therefore, it was suggested that this could be established as a new indicator for estimating time since death.

Free Research Field

法医学

Academic Significance and Societal Importance of the Research Achievements

死後経過時間を推定することは、我が国における社会の安全や治安維持等も含めて法務実務上重要な課題の１つである。しかしながら、現段階では死後経過時間の推定には確固たる指標が存在せず、種々の情報を組み合わせることでそれらを導き出している。また、それら情報の判断には主観的要素が強くいため、正確な死後経過時間を導出することに困難な状況になっている。本方法が確立することで客観的な指標の１つとなり、より精度の高い死後経過時間の推定に寄与するものと考える。