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Abbate JM, Grifò G, Capparucci F, Arfuso F, Savoca S, Cicero L, Consolo G, Lanteri G. Postmortem Electrical Conductivity Changes of Dicentrarchus labrax Skeletal Muscle: Root Mean Square (RMS) Parameter in Estimating Time since Death. Animals (Basel) 2022; 12:ani12091062. [PMID: 35565489 PMCID: PMC9105913 DOI: 10.3390/ani12091062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 11/29/2022] Open
Abstract
Simple Summary The estimation of postmortem interval (PMI) still poses a major challenge for pathologists worldwide, making the search for new and more accurate technologies to assist in PMI estimation worthy of growing scientific interest. This study aimed to explore for the first time the use of an oscilloscope coupled with a signal generator, as innovative technology, to evaluate changes in the electrical conductivity of skeletal muscle of sea bass specimens during the early postmortem interval, to find an accurate, quantitative parameter useful in PMI estimation. The use of the oscilloscope, especially for the RMS measured parameter, has been shown here as a promising technology for studying dielectric muscle properties during the early postmortem interval, with the advantage of being a rapid, non-destructive, and inexpensive method. Abstract Electric impedance spectroscopy techniques have been widely employed to study basic biological processes, and recently explored to estimate postmortem interval (PMI). However, the most-relevant parameter to approximate PMI has not been recognized so far. This study investigated electrical conductivity changes in muscle of 18 sea bass specimens, maintained at different room temperatures (15.0 °C; 20.0 °C; 25.0 °C), during a 24 h postmortem period using an oscilloscope coupled with a signal generator, as innovative technology. The root mean square (RMS) was selected among all measured parameters, and recorded every 15 min for 24 h after death. The RMS(t) time series for each animal were collected and statistically analyzed using MATLAB®. A similar trend in RMS values was observed in all animals over the 24 h study period. After a short period, during which the RMS signal decreased, an increasing trend of the signal was recorded for all fish until it reached a peak. Subsequently, the RMS value gradually decreased over time. A strong linear correlation was observed among the time series, confirming that the above time-behaviour holds for all animals. The time at which maximum value is reached strongly depended on the room temperature during the experiments, ranging from 6 h in fish kept at 25.0 °C to 14 h in animals kept at 15.0 °C. The use of the oscilloscope has proven to be a promising technology in the study of electrical muscle properties during the early postmortem interval, with the advantage of being a fast, non-destructive, and inexpensive method, although more studies will be needed to validate this technology before moving to real-time field investigations.
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Affiliation(s)
- Jessica Maria Abbate
- Department of Veterinary Sciences, University of Messina, Polo Universitario Annunziata, 98168 Messina, Italy; (J.M.A.); (F.A.)
| | - Gabriele Grifò
- Department of Mathematical, Computer, Physical and Earth Sciences, University of Messina, Polo Universitario Papardo, 98166 Messina, Italy; (G.G.); (G.C.)
| | - Fabiano Capparucci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Polo Universitario Papardo, 98166 Messina, Italy; (F.C.); (G.L.)
| | - Francesca Arfuso
- Department of Veterinary Sciences, University of Messina, Polo Universitario Annunziata, 98168 Messina, Italy; (J.M.A.); (F.A.)
| | - Serena Savoca
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, 98125 Messina, Italy;
- National Research Council, Institute for Marine Biological Resources and Biotechnology (IRBIM), 98122 Messina, Italy
| | - Luca Cicero
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Polo Universitario Papardo, 98166 Messina, Italy; (F.C.); (G.L.)
- Experimental Zooprophylactic Institute of Sicily “A. Mirri” (IZS), 98129 Palermo, Italy
- Correspondence:
| | - Giancarlo Consolo
- Department of Mathematical, Computer, Physical and Earth Sciences, University of Messina, Polo Universitario Papardo, 98166 Messina, Italy; (G.G.); (G.C.)
| | - Giovanni Lanteri
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Polo Universitario Papardo, 98166 Messina, Italy; (F.C.); (G.L.)
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Hansen ES, Baigent C, Reck SI, Connor M. Bioelectrical Impedance as a Technique for Estimating Postmortem Interval,. J Forensic Sci 2017; 63:1186-1190. [PMID: 29143324 DOI: 10.1111/1556-4029.13695] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 11/29/2022]
Abstract
Estimation of postmortem interval (PMI) is a critical component of death investigation. A cadaver can be hypothesized to be a resistor-capacitor (RC) circuit the impedance (Z) of which changes in a quantifiable manner as the cadaver decomposes. This hypothesis was tested using bioelectrical impedance analysis (BIA) equipment to apply a current with a fixed amplitude at a single frequency to four cadavers over time and measuring two components of Z, resistance (R) and reactance (Xc ). Quadratic regression analysis between Z and accumulated degree days (ADD) showed a statistically significant parabolic relationship. The parabolic relationship poses an initial challenge to the use of the method, and additional research is needed to address this issue. However, the results of the reported research support the hypothesis that Z measured using BIA has a relationship to PMI.
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Affiliation(s)
- Eriek S Hansen
- Department of Biological Sciences, Colorado Mesa University, 1100 North Avenue, Grand Junction, CO, 81501
| | - Christiane Baigent
- Department of Social and Behavioral Sciences, Forensic Investigation Research Station, Colorado Mesa University, 1100 North Avenue, Grand Junction, CO, 81501
| | - Sophia I Reck
- Department of Biological Sciences, Colorado Mesa University, 1100 North Avenue, Grand Junction, CO, 81501
| | - Melissa Connor
- Department of Social and Behavioral Sciences, Forensic Investigation Research Station, Colorado Mesa University, 1100 North Avenue, Grand Junction, CO, 81501
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Wang Q, He H, Li B, Lin H, Zhang Y, Zhang J, Wang Z. UV-Vis and ATR-FTIR spectroscopic investigations of postmortem interval based on the changes in rabbit plasma. PLoS One 2017; 12:e0182161. [PMID: 28753641 PMCID: PMC5533326 DOI: 10.1371/journal.pone.0182161] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/13/2017] [Indexed: 11/23/2022] Open
Abstract
Estimating PMI is of great importance in forensic investigations. Although many methods are used to estimate the PMI, a few investigations focus on the postmortem redistribution. In this study, ultraviolet-visible (UV-Vis) measurement combined with visual inspection indicated a regular diffusion of hemoglobin into plasma after death showing the redistribution of postmortem components in blood. Thereafter, attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy was used to confirm the variations caused by this phenomenon. First, full-spectrum partial least-squares (PLS) and genetic algorithm combined with PLS (GA-PLS) models were constructed to predict the PMI. The performance of GA-PLS model was better than that of full-spectrum PLS model based on its root mean square error (RMSE) of cross-validation of 3.46 h (R2 = 0.95) and the RMSE of prediction of 3.46 h (R2 = 0.94). The investigation on the similarity of spectra between blood plasma and formed elements also supported the role of redistribution of components in spectral changes in postmortem plasma. These results demonstrated that ATR-FTIR spectroscopy coupled with the advanced mathematical methods could serve as a convenient and reliable tool to study the redistribution of postmortem components and estimate the PMI.
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Affiliation(s)
- Qi Wang
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Haijun He
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Bing Li
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Hancheng Lin
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Yinming Zhang
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Ji Zhang
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Zhenyuan Wang
- Department of Forensic Pathology, College of Forensic Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, China
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Li C, Wang Q, Zhang Y, Lin H, Zhang J, Huang P, Wang Z. Research progress in the estimation of the postmortem interval by Chinese forensic scholars. Forensic Sci Res 2016; 1:3-13. [PMID: 30483604 PMCID: PMC6197124 DOI: 10.1080/20961790.2016.1229377] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 08/23/2016] [Indexed: 10/25/2022] Open
Abstract
The determination of time since death or the postmortem interval (PMI) is one of the most important and frequently asked questions in forensic medicine. Medicolegal scholars and forensic pathologists around the world have studied the estimation of PMI extensively in the past, and many novel methods and advanced technologies have now been applied in the field. For several centuries, Chinese forensic examiners have also worked on the estimation of the PMI, and there are a large number of excellent studies published in Chinese rather than in English, and these are not easily accessible or known internationally. Therefore we have conducted a review of relevant studies published by Chinese forensic scholars in the last few decades. The scope of this review is to provide a concise summary of the current progress in the estimation of PMI by Chinese forensic researchers using molecular biology, spectroscopic technology, entomological methods, energy changes, thanatochemistry and other methods.
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Affiliation(s)
- Chengzhi Li
- School of Forensic Science and Medicine, Xi'an Jiaotong University, Xi'an, China.,Shanghai Key Laboratory of Forensic Science, Shanghai Forensic Service Platform, Institute of Forensic Science, Ministry of Justice, PRC, Shanghai, China
| | - Qi Wang
- School of Forensic Science and Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Yinming Zhang
- School of Forensic Science and Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Hancheng Lin
- School of Forensic Science and Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Ji Zhang
- School of Forensic Science and Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Ping Huang
- Shanghai Key Laboratory of Forensic Science, Shanghai Forensic Service Platform, Institute of Forensic Science, Ministry of Justice, PRC, Shanghai, China
| | - Zhenyuan Wang
- School of Forensic Science and Medicine, Xi'an Jiaotong University, Xi'an, China
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The experimental design of postmortem studies: the effect size and statistical power. Forensic Sci Med Pathol 2016; 12:343-9. [PMID: 27412160 PMCID: PMC4967085 DOI: 10.1007/s12024-016-9793-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2016] [Indexed: 01/06/2023]
Abstract
Purpose The aim is of this study was to show the poor statistical power of postmortem studies. Further, this study aimed to find an estimate of the effect size for postmortem studies in order to show the importance of this parameter. This can be an aid in performing power analysis to determine a minimal sample size. Methods GPower was used to perform calculations on sample size, effect size, and statistical power. The minimal significance (α) and statistical power (1 − β) were set at 0.05 and 0.80 respectively. Calculations were performed for two groups (Student’s t-distribution) and multiple groups (one-way ANOVA; F-distribution). Results In this study, an average effect size of 0.46 was found (n = 22; SD = 0.30). Using this value to calculate the statistical power of another group of postmortem studies (n = 5) revealed that the average statistical power of these studies was poor (1 − β < 0.80). Conclusion The probability of a type-II error in postmortem studies is considerable. In order to enhance statistical power of postmortem studies, power analysis should be performed in which the effect size found in this study can be used as a guideline.
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Wang H, He Y, Yan Q, You F, Fu F, Dong X, Shi X, Yang M. Correlation between the dielectric properties and biological activities of human ex vivo hepatic tissue. Phys Med Biol 2015; 60:2603-17. [PMID: 25761728 DOI: 10.1088/0031-9155/60/6/2603] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Dielectric properties are vital biophysical features of biological tissues, and biological activity is an index to ascertain the active state of tissues. This study investigated the potential correlation between the dielectric properties and biological activities of human hepatic tissue with prolonged ex vivo time through correlation and regression analyses. The dielectric properties of 26 cases of normal human hepatic tissue at 10 Hz to 100 MHz were measured from 15 min after isolation to 24 h at 37 °C with 90% humidity. Cell morphologies, including nucleus area (NA) and alteration rate of intercellular area (ICAR), were analyzed as indicators of biological activities. Conductivity, complex resistivity, and NA exhibited opposing changes 1 h after isolation. Relative permittivity and ex vivo time were not closely correlated (p > 0.05). The dielectric properties measured at low frequencies (i.e. <1 MHz) were more sensitive than those measured at high frequencies in reflecting the biological activity of ex vivo tissue. Highly significant correlations were found between conductivity, resistivity and the ex vivo time (p < 0.05) as well as conductivity and the cell morphology (p < 0.05). The findings indicated that establishing the correlation between the dielectric properties and biological activities of human hepatic tissue is of great significance for promoting the role of dielectric properties in biological science, particularly in human biology.
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Affiliation(s)
- Hang Wang
- Department of Biomedical Engineering, Fourth Military Medical University, 169 West Changle Road, 710032, Xi'an, People's Republic of China
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Estimation of PMI depends on the changes in ATP and its degradation products. Leg Med (Tokyo) 2013; 15:235-8. [PMID: 23639682 DOI: 10.1016/j.legalmed.2013.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/18/2013] [Accepted: 03/27/2013] [Indexed: 11/24/2022]
Abstract
Estimating the time since death, or postmortem interval (PMI), has been one of the biggest difficulties in modern forensic investigation. This study tests if the concentrations of breakdown products of adenosine triphosphate (ATP) correlate with PMI in multiple organs from rat. Brains, spleens, and kidneys of rats were harvested at different time points in carcasses maintained at 4°C or 20°C. High Performance Liquid Chromatography (HPLC) was used to quantify concentrations of metabolites related to ATP degradation. A K value (Kv=100×(Hx+HxR)/(ATP+ADP+AMP+IMP+HxR+Hx)) was calculated and correlated with PMI for each organ and temperature. The results indicate that the K value is a robust index for the estimation of PMI based on highly significant linear correlations between PMI and concentrations of ATP breakdown products. Compared with other current research methods, the changing tendency of ATP and its degradation products may be potentially a better way for the estimation of PMI in medico-legal practice.
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Dorandeu A, Lorin de la Grandmaison G. [Contribution of the TUNEL method for post-mortem interval estimation: an experimental study]. Ann Pathol 2013; 33:80-3. [PMID: 23582832 DOI: 10.1016/j.annpat.2012.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 11/12/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Abstract
The assessment of post-mortem interval is of major importance in forensic pathology. Many methods have been used in the early post-mortem period but remain rough. To test the hypothesis of an increased rate of apoptosis increasing with post-mortem interval, TUNEL method was applied in rats to study the relationship between the number of apoptotic cells in skin samples and the post-mortem interval. Our study showed that the post-mortem processes were associated with apoptosis in skin cells. The apoptosis rate was statistically correlated with post-mortem interval in the early post-mortem (less than 48 hours after death). The application of the TUNEL method for estimating the post-mortem interval in forensic pathology is discussed.
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Affiliation(s)
- Anne Dorandeu
- Service de médecine légale, hôpital Lapeyronie, 371, avenue du Doyen-Gaston-Giraud, 34295 Montpellier cedex 5, France
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