Silva-Bessa Angela, Ramage Stuart, Ferreira Maria Teresa, Dinis-Oliveira Ricardo Jorge, Forbes Shari L, Dawson Lorna
Centre for Functional Ecology, Laboratory of Forensic Anthropology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
Associate Laboratory i4HB - Institute for Health and Bioeconomy, University Institute of Health Sciences - CESPU, 4585-116, Gandra, Portugal.
Int J Legal Med. 2025 Mar 26. doi: 10.1007/s00414-025-03476-4.
Postmortem interval (PMI) estimation is a challenging task in forensic investigations. PMI assessment frequently requires the application of the currently available methods which can lead to unsatisfactory results due to the poor accuracy of time interval estimation. To address these concerns, the present study aimed to evaluate whether there is a correlation between human hair proteolysis and PMI. Scalp hair samples of three living donors and eleven individuals exhumed from different burial types from Portuguese cemeteries were analysed by ATR-FTIR (attenuated total reflectance - Fourier-transform infrared). Four band areas and three hair degradation indices were considered in the 2000-1000 cm spectral region. When analysing the entire dataset (i.e., 126 infrared spectra) - and when separating and analysing the spectroscopic data by burial type - the ratio between amide II (∼1550 cm) and S = O and SO combined (∼1074 cm and ∼1043 cm, respectively) suggests there is a correlation between hair proteolysis and PMI (p < 0.05). Nevertheless, it is recommended that a larger dataset is required to confirm the preliminary results obtained in this study and to explore how this correlation can be used to estimate PMI in forensic casework.
死后间隔时间（PMI）的估计是法医调查中的一项具有挑战性的任务。PMI评估通常需要应用当前可用的方法，由于时间间隔估计的准确性较差，这些方法可能会导致不尽人意的结果。为了解决这些问题，本研究旨在评估人类头发蛋白水解与PMI之间是否存在相关性。通过衰减全反射傅里叶变换红外光谱（ATR-FTIR）分析了三名在世捐赠者以及从葡萄牙墓地不同埋葬类型中挖掘出的11个人的头皮毛发样本。在2000-1000 cm光谱区域考虑了四个谱带区域和三个毛发降解指数。在分析整个数据集（即126个红外光谱）时，以及按埋葬类型分离和分析光谱数据时，酰胺II（1550 cm）与S=O和SO总和（分别为1074 cm和~1043 cm）之间的比率表明头发蛋白水解与PMI之间存在相关性（p<0.05）。然而，建议需要更大的数据集来确认本研究中获得的初步结果，并探索这种相关性如何用于法医案件工作中PMI的估计。
