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The properties and structure of the crystalline lens change as time after death passes. Some experiments have suggested that these might be used to estimate the postmortem interval (PMI). In this study, the organization and texture of the rabbit lens were objectively evaluated as a function of the PMI using two-photon excitation fluorescence (TPEF) imaging microscopy. Between 24 h and 72 h, the lens presented a highly organized structure, although the fiber delineation was progressively vanishing. At 96 h, this turned into a homogeneous pattern where fibers were hardly observed. This behaviour was similar for parameters providing information on tissue texture. On the other hand, the fiber density of the lens is linearly reduced with the PMI. On average, density at 24 h was approximately two-fold when compared to 96 h after death. The present results show that TPEF microscopy combined with different quantitative tools can be used to objectively monitor temporal changes in the lens fiber organization after death. This might help to estimate the PMI, which is one of the most complex problems in forensic science.

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The diagnosing of drowning remains one of the most challenging activities for the forensic pathologist. There is little information on the impact on the lung as a target organ in death by drowning. We aimed to investigate the concentration of trace elements in the lungs of people who had suffered different types of death to evaluate the discriminating ability of trace elements to identify seawater drowning (SWD). A total of 11 trace elements were analyzed by Inductively Coupled Plasma-Mass Spectrometry in 74 forensic cases. Sampler scanning electron microscopy and Energy Dispersive X-ray spectroscopy (EDX) were used to identify ultrastructural lung alterations. A Principal Component Analysis (PCA) of trace elements was carried out. The trace elements in SWD lungs were detected in the following order of concentration: Br˃Zn˃Sr˃Cr˃Cu˃As˃Pb˃Se˃Mn˃Ni˃Cd. Our results showed significantly higher concentrations of Br and Sr (P = 0.010 and P = 0.000) and significantly lower concentrations of Zn, Pb, Cu, Cd, and Se in SWD compared with other causes of death. After adjusting by confounder factors, Sr and Br remained as predictive independent factors for diagnosis of drowning (p = 0.042, in both cases). These results were confirmed by PCA, which revealed a wide separation between SWD and the rest of the causes of death. Our SWD cohort was characterized by high concentrations of the trace elements Br and Sr and low concentrations of Zn, Pb, Cu, Cd, and Se in lung tissue, while PCA showed its discriminatory capacity to identify death by seawater drowning. These findings, together with those obtained using other techniques, can be of great importance in the diagnosis of SWD.

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Teeth are a fundamental tool in forensic odontology for identification in a legal context of those individuals who cannot be identified visually or by other means. Dentine presents physiological exchanges of in trace elements after a period of mineralization and several factors can affect its concentration. The aim of this study was to investigate the concentration of 25 trace elements in the coronal dentine according to sex and type of tooth to determine their relationship with age. A total of 25 trace elements were analyzed in 150 human coronal dentine. Teeth were classified into three age groups, sex and tooth type. The trace elements were grouped as potentially toxic or essential. Inductively Coupled Plasma-Mass Spectrometry and Atomic Emission Spectroscopy were used. The toxic and essential elements were detected in the following order of concentration: Al > Pb > Sn > Li > As > Cd and Ca > P > Mg > Na > S > K > Sr > Zn > Ba > Fe > B > Ti > Mn > Cr > Ni > Cu > Co > Se > V. Our findings show an increase in the concentration of toxic (Pb, Li and Sn) and essential (B, Ba, K, Sr, S and Mg) elements in coronal dentin related to the age of the teeth, regardless of sex. The concentrations of Pb and K in dentin of molars and premolars are the elements that best relate their variations with age. In view of our results, the analysis of these trace elements in dentin in combination with other types of techniques could be established as an element to consider in age dating studies in different forensic situations.

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Proteomic techniques in bones forensic samples are increasingly, being applied. The main aim of forensic sciences is the estimation of postmortem interval. Most current techniques are useful for the first post-mortem stages. However, in the case of osseous remains, these techniques may be difficult to use due to the high level of decomposition of the sample. Our objective was to attempt to know whether there is a protein profile in human bone remains that would enable a late postmortem. interval ranging from 5 to 20 years postmortem to be estimated. A total of 40 femur bones from 40 different cadavers (data range 5-20 years) were use. Of the 275 total proteins, we excluded the circulating ones (n = 227), leaving a total of 48 proteins (29 structural and 19 functional) were found. A multiple correspondence analysis was applied on the 48 proteins. Finally selecting 32 proteins that allowed us to discriminate between the. two groups of postmortem interval. Analysis of the protein profile present in bone permits an approximation of the date of death within the studied interval, and could be used to complement other tests for estimating the postmortem interval.

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Estimating the postmortem interval (PMI) is an important goal in forensic medicine and continues to be one of the most difficult tasks of the forensic investigator. Few accurate methods exist to determine the time since death of skeletonized human remains due to the great number of intrinsic and external factors that may alter the normal course of postmortem change. The purpose of this research was to assess the usefulness of various biochemical parameters, such as nitrogenous bases (adenine, guanine, purines, cytosine, thymine, pyrimidines, hypoxanthine and xanthine), DNA and Collagen Type I peptides to estimate PMI. These parameters were analysed in cortical bone for the establishment of data in a total of 80 long bones of 80 corpses (50 males, 30 females) with a mean age of 68.31 years (S.D.=18.021, range=20-97). The bones were removed from the cement niches of a cemetery in Murcia (south-eastern Spain), where they had lain for between 5 and 47 years (mean time 23.83 years, S.D.=10.85). Our results show a significant decrease in adenine (p=0.0004), guanine (p=0.0001), purines (p=0.0001), cytosine (p=0.0001), thymine (p=0.0226), pyrimidines (p=0.0002) and the number of peptides of Collagen type I (p=0.0053) in those with a PMI≥20 years. In a curvilinear regression analysis the results show that 30.6% of the variable PMI could be explained by guanine concentration, in bones with a PMI<20 years, while in cases of a PMI≥20 years, the variable that best explained membership of this group was adenine (38.0%). In the discriminant analysis applied to the all the variables as a function of PMI when two groups were established, 86.7% of the cases were correctly classified. These results show that the quantification of Collagen type I proteins and nitrogenous bases could be used as a complementary tool, together with other analyses, in the estimation of PMI.

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Forensic pathology often uses osteobiography, which involves biological profiles based on a determination of the age, sex, constitution, pathological states and other anomalies (paleopathology) of subjects for identification purposes. In this paper, proteins were analysed in bone remains. A total of 45 long bones from 45 different cadavers (29 males, 16 females) with a mean age of 66.31 years (S.D.=19.48, range 20-97) were used to search for pathological biomarkers which are closely related to several diseases. The bones were removed from the cement niches of a cemetery in Murcia (south-eastern Spain), where they had lain for between 18 and 45 years (mean time 25.84 years, S.D.=8.91). After a specific extraction using Tris-Urea buffer, were measured using HPLC/MS/MS. Our results show that proteins resulting from tumoral diseases and bacterial and viral pathogens can be detected and identified in the skeletal remains, making them useful pathological biomarkers for constructing biological profiles.

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Establishing the postmortem interval is a very complex problem in Forensic Science despite the existence of several macro- and microscopic methods. In the case of ocular methods, most are based on an evaluation of the biochemical components of the vitreous humour 24-36h after death, but, to our knowledge, there are no studies on the relationship between lens and the postmortem interval. Since the lens is protected between the vitreous humour and the aqueous humour inside the eyeball, postmortem changes are assumed to start later in the lens. To evaluate the usefulness of using the lens to establish the postmortem interval, we examined 80 rabbit lens enucleated 24, 48, 72 and 96h after death, assessing changes in sphericity and absorbance at different wavelengths and any histological alterations. Both sphericity and absorbance were seen to decrease to a statistically significant extent, and there was a gradual loss of structure and organisation of the lens components as a function of the postmortem interval. Modifications in the lens were seen to be useful for determining the postmortem interval between 24 and 96h.

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