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Cordeiro C.,National Institute of Legal Medicine and Forensic science Center Branch | Cordeiro C.,University of Coimbra | Seoane R.,University of Santiago de Compostela | Camba A.,University of Santiago de Compostela | And 5 more authors.
Journal of Forensic Sciences | Year: 2015

Research into maximizing the speed, precision, and reliability of estimating the postmortem interval (PMI) has been a recurring object of investigation and methodologies based on the vitreous humor (VH) have provided good results. However, contamination from causes not readily apparent, such as blood, can occur, and thus lead not only to an erroneous estimation of PMI, but also interfere with the correct identification of other substances in the VH. We have developed a flow cytometry method which quantifies blood contamination and is able to detect erythrocytes in 1:750,000 dilution of contaminated VH which affects the results of hypoxanthine. It is an improvement on the previous more complex mass spectrometry method, being faster, more sensitive, and readily available. As such, it could be proposed for the rapid screening of appropriate samples by detecting and eliminating blood contaminated samples from PMI estimation. © 2015 American Academy of Forensic Sciences . Source

Rodriguez S.,University of Santiago de Compostela | Gonzalez A.,University of Santiago de Compostela | Simon A.,National Institute of Legal Medicine and Forensic science Center Branch | Rodriguez-Calvo M.S.,University of Santiago de Compostela | And 4 more authors.
Legal Medicine | Year: 2014

This study evaluates the efficacy of a radiological method to estimate stature from measurements of the first and second metatarsal taken from a collection of metatarsals of a Portuguese Caucasian population in which the measurements were made directly on the bone. The highest coefficient of determination and the lowest standard error were obtained with the physiological length of the second metatarsal (F2), using the equation S=895.4803+10.7848F2. The linear regressions obtained show significant differences between the estimated heights from M1. In addition, we offer a simple method for sex determination based on the maximum length (M1) and width (W1) of the first metatarsal, where W1=x1; (M1/W1)=x2; β0=55.4767; β1=-2.5796 and β2=-4.6898. Here we present a method of measurement using computerized tomography that enables population studies using live volunteers without incurring the difficulties of on the bone measurement. © 2014 Elsevier Ireland Ltd. Source

Monteiro C.,National Institute of Legal Medicine and Forensic science Center Branch | Monteiro C.,Forensic Science Center | Franco J.M.,National Institute of Legal Medicine and Forensic science Center Branch | Franco J.M.,Forensic Science Center | And 11 more authors.
Forensic Science International | Year: 2014

A simple and sensitive procedure, using n-propanol as internal standard (IS), was developed and validated for the qualitative and quantitative analysis of a group of 11 volatile organic substances with different physicochemical properties (1-butanol, 2-propanol, acetaldehyde, ethyl acetate, acetone, acetonitrile, chloroform, diethyl ether, methanol, toluene and p-xylene) in whole blood, urine and vitreous humor. Samples were prepared by dilution with an aqueous solution of internal standard followed by Headspace Gas Chromatography with a Flame-ionization Detector (HS GC-FID) analysis. Chromatographic separation was performed using two capillary columns with different polarities (DB-ALC2: 30. m. ×. 0.320. mm. ×. 1.2. μm and DB-ALC1: 30. m. ×. 0.320. mm. ×. 1.8. μm), thus providing a change in the retention and elution order of volatiles. This dual column confirmation increases the specificity, since the risk of another substance co-eluting at the same time in both columns is very small. The method was linear from 5 to 1000. mg/L for toluene and p-xylene, 50-1000. mg/L for chloroform, and 50-2000. mg/L for the remaining substances, with correlation coefficients of over 0.99 for all compounds. The limits of detection (LOD) ranged 1 to 10. mg/L, while the limits of quantification (LOQ) ranged from 2 to 31. mg/L. The intra-day precision (CV. <. 6.4%), intermediate precision (CV. <. 7.0%) and accuracy (relative error ±10%) of the method were in conformity with the criteria normally accepted in bioanalytical method validation. The method developed has been applied to forensic cases, with the advantages that it uses a small sample volume and does not require any extraction procedure as it makes use of a headspace injection technique. © 2014. Source

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