Johann Zwirner, Pavithran Devananthan, Paul D Docherty, Benjamin Ondruschka, Natalia Kabaliuk
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Thirty sheep brains were examined, including the frontal lobe, parietal lobe, anterior and posterior deep brain, superior colliculi, pons, medulla, and cerebellum. Rheometry tests were conducted, and receiver operator characteristic analyses were employed to establish cut-off values. At 4 °C storage, all investigated biomechanical properties of the examined brain regions remained stable for at least one day post-mortem. Using cerebellar samples stored at 4 °C, a post-mortem interval of at least two days could be determined with excellent diagnostic ability. Complex shear modulus values below 1435 Pa or storage modulus values below 1313 Pa allowed prediction of two or more days post-mortem. Comparisons between 4 °C and 20 °C revealed brain region-specific results. For instance, the complex shear moduli of the anterior deep brain at 4 °C were significantly higher on all individual testing days when compared to 20 °C. In contrast, the combined medulla and pons samples were similar on each day. Rheometry testing of brain tissue consistently stored at 4 °C since death proved valuable for forensic time since death estimations starting from two days after death.</p>","PeriodicalId":14071,"journal":{"name":"International Journal of Legal Medicine","volume":" ","pages":"2541-2549"},"PeriodicalIF":2.2000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11490522/pdf/","citationCount":"0","resultStr":"{\"title\":\"The influence of cooling on biomechanical time since death estimations using ovine brain tissue.\",\"authors\":\"Johann Zwirner, Pavithran Devananthan, Paul D Docherty, Benjamin Ondruschka, Natalia Kabaliuk\",\"doi\":\"10.1007/s00414-024-03267-3\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>The significance of biomechanical analyses for forensic time since death estimations has recently been demonstrated. Previous biomechanical analyses successfully discriminated post-mortem brain tissue from tissue with a post-mortem interval of at least one day when held at 20 °C. However, the practical utility of such analyses beyond day one at 20 °C was limited. This study investigates the storage, loss, and complex shear modulus of various brain regions in sheep stored at 4 °C in 24-hour intervals over four days post-mortem using rheometry tests. The aim is to identify the critical biomechanical tissue property values to predict post-mortem time and assess the temperature sensitivity of the rheometry method by comparing results to recent findings at 20 °C. Thirty sheep brains were examined, including the frontal lobe, parietal lobe, anterior and posterior deep brain, superior colliculi, pons, medulla, and cerebellum. Rheometry tests were conducted, and receiver operator characteristic analyses were employed to establish cut-off values. At 4 °C storage, all investigated biomechanical properties of the examined brain regions remained stable for at least one day post-mortem. Using cerebellar samples stored at 4 °C, a post-mortem interval of at least two days could be determined with excellent diagnostic ability. Complex shear modulus values below 1435 Pa or storage modulus values below 1313 Pa allowed prediction of two or more days post-mortem. Comparisons between 4 °C and 20 °C revealed brain region-specific results. For instance, the complex shear moduli of the anterior deep brain at 4 °C were significantly higher on all individual testing days when compared to 20 °C. In contrast, the combined medulla and pons samples were similar on each day. 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引用次数: 0
摘要
生物力学分析对法医估计死亡时间的重要性最近得到了证实。以前的生物力学分析成功地将死后脑组织与在 20 °C下至少间隔一天的组织区分开来。然而,此类分析在 20 °C下保存一天后的实际效用有限。本研究使用流变仪测试方法,研究了绵羊死后四天内以 24 小时为间隔在 4 °C 下保存的不同脑区的储存、损耗和复合剪切模量。目的是确定关键的生物力学组织属性值,以预测死后时间,并通过将结果与最近在 20 °C 下的研究结果进行比较,评估流变学方法的温度敏感性。研究人员检查了 30 个绵羊大脑,包括额叶、顶叶、大脑前部和后部深部、上丘、脑桥、延髓和小脑。进行了流变学测试,并采用接收器操作者特征分析法确定了临界值。在 4 °C的储存条件下,所有受检脑区的生物力学特性在死后至少一天内都保持稳定。小脑样本在 4 °C下保存,可以确定死后至少两天的间隔时间,诊断能力极强。低于1435帕的复合剪切模量值或低于1313帕的储存模量值可预测死后两天或更长时间。4 °C和20 °C之间的比较显示了特定脑区的结果。例如,与 20 °C相比,4 °C下大脑前深部的复合剪切模量在所有测试日都明显较高。相比之下,髓质和脑桥的组合样本在每一天的测试结果都相似。对死亡后一直保存在 4 ° C 的脑组织进行流变仪测试,证明对法医从死亡后两天开始估算死亡时间很有价值。
The influence of cooling on biomechanical time since death estimations using ovine brain tissue.
The significance of biomechanical analyses for forensic time since death estimations has recently been demonstrated. Previous biomechanical analyses successfully discriminated post-mortem brain tissue from tissue with a post-mortem interval of at least one day when held at 20 °C. However, the practical utility of such analyses beyond day one at 20 °C was limited. This study investigates the storage, loss, and complex shear modulus of various brain regions in sheep stored at 4 °C in 24-hour intervals over four days post-mortem using rheometry tests. The aim is to identify the critical biomechanical tissue property values to predict post-mortem time and assess the temperature sensitivity of the rheometry method by comparing results to recent findings at 20 °C. Thirty sheep brains were examined, including the frontal lobe, parietal lobe, anterior and posterior deep brain, superior colliculi, pons, medulla, and cerebellum. Rheometry tests were conducted, and receiver operator characteristic analyses were employed to establish cut-off values. At 4 °C storage, all investigated biomechanical properties of the examined brain regions remained stable for at least one day post-mortem. Using cerebellar samples stored at 4 °C, a post-mortem interval of at least two days could be determined with excellent diagnostic ability. Complex shear modulus values below 1435 Pa or storage modulus values below 1313 Pa allowed prediction of two or more days post-mortem. Comparisons between 4 °C and 20 °C revealed brain region-specific results. For instance, the complex shear moduli of the anterior deep brain at 4 °C were significantly higher on all individual testing days when compared to 20 °C. In contrast, the combined medulla and pons samples were similar on each day. Rheometry testing of brain tissue consistently stored at 4 °C since death proved valuable for forensic time since death estimations starting from two days after death.
期刊介绍:
The International Journal of Legal Medicine aims to improve the scientific resources used in the elucidation of crime and related forensic applications at a high level of evidential proof. The journal offers review articles tracing development in specific areas, with up-to-date analysis; original articles discussing significant recent research results; case reports describing interesting and exceptional examples; population data; letters to the editors; and technical notes, which appear in a section originally created for rapid publication of data in the dynamic field of DNA analysis.