Academic literature on the topic 'Postmortem intervals'

Orientador: Arício Xavier Linhares<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia<br>Made available in DSpace on 2018-08-21T03:37:18Z (GMT). No. of bitstreams: 1 Rezende_Fabio_M.pdf: 2094464 bytes, checksum: d1870c6b30f983e3d34cc084165c6f12 (MD5) Previous issue date: 2012<br>Resumo: O aumento no número de óbitos relacionados ao uso de drogas justifica o interesse por estudos entomotoxicológicos. Estes estudos devem focar a obtenção de dados diversos sobre a entomofauna necrófaga que contribuam para a formação de um banco de dados que auxilie em investigações criminais, principalmente quando a estimativa do intervalo pós-morte (IPM) é baseada na idade do inseto, visto que a mesma pode sofrer alteração quando uma dada substância interfere no ciclo de insetos que tenham se alimentado dos tecidos cadavéricos onde tais substâncias estão presentes. Assim, no presente estudo objetivou-se verificar o efeito de diferentes concentrações de Cloridrato de Metilfenidato isolado e associado ao Fenobarbital na taxa de desenvolvimento, sobrevivência e longevidade de imaturos de Chrysomya putoria (Wiedemann), Chrysomya albiceps (Wiedemann) e Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), quando acrescidos em dieta artificial oferecida como único substrato para seu desenvolvimento. Os imaturos foram obtidos a partir de colônias de moscas adultas mantidas em condições controladas de temperatura e umidade em laboratório. Foram feitas seis réplicas para cada grupo experimental, com 150 espécimes de cada espécie em questão, perfazendo um total de 900 larvas por espécie. Além disso, um grupo controle (sem adição da droga) foi mantido sob as mesmas condições de criação. Os imaturos foram pesados individualmente a cada 12h, sendo retirados 10 espécimes de cada grupo, desde as 12 horas após a eclosão até a pupariação. ANOVA de um fator foi realizada para comparar o efeito dos tratamentos no desenvolvimento dos imaturos, usando como resposta o ganho de massa larval. O teste de comparações múltiplas de Duncan também foi realizado para comparar as médias e apontar possíveis diferenças entre os grupos. As duas substâncias alteraram a taxa de desenvolvimento de todas as espécies estudadas, ampliando em até dois dias o tempo total de desenvolvimento dos imaturos. Desse modo seria recomendável que exames toxicológicos para a detecção de drogas em larvas fossem realizados invariavelmente para evitar erros quanto à estimativa do IPM, quando este for baseado no ciclo de desenvolvimento de insetos<br>Abstract: The increase on the number of deaths related to drug abuse justifies the interest in entomotoxicological studies. These studies are focused on obtaining data on the necrophagous insect fauna which contribute to the formation of a database to help in criminal investigations, especially when the estimate of the postmortem interval (PMI) is based on the age of immature necrophagous insect, since it can be altered when a given substance interferes with the larval development of insects that have fed on tissues containing this substance. The present study was aimed to evaluate the effect of different concentrations of methylphenidate hydrochloride isolated and associated with phenobarbital on the developmental rate, survival and longevity of immatures of Chrysomya putoria (Wiedemann), Chrysomya albiceps (Wiedemann) and Chrysomya megacephala (Fabricius ) (Diptera: Calliphoridae), reared in artificial diets with different concentrations of the drugs and offered as substrate for their development. The immatures were obtained from colonies of adult flies maintained under controlled temperature and humidity in the laboratory. Six replicates were performed for each experimental group, with 150 specimens of each species of blowfly, comprising a total of 900 larvae per group. In addition, a control group was maintained under the same conditions established for the other groups. Ten specimens of each group were removed and individually weighed every 12 hours, from 12 hours after hatching to pupariation. One-way ANOVA was performed to compare the effect of treatment on development of immatures, using larval weight as response variable. The Duncan Multiple Comparison Test was also performed to compare the means and to identify possible differences among the groups. The two substances were responsible for altering the rate of development of all species studied, retarding up to two days the total developmental time of the immatures. Thus, it is recommended that toxicological tests should be performed to detect drugs eventually present on larvae collected from corpses, in order to prevent errors in the estimation of IPM, when it is based on the developmental cycle of immature saprophagous insects<br>Mestrado<br>Parasitologia<br>Mestre em Parasitologia

Pesquisas têm documentado como é variável a decomposição corporal e o intervalo de tempo verificado entre as diversas fases do processo de decomposição do cadáver e o momento em que se verificou a morte. Fatores ambientais como temperatura, umidade, condições aeróbica e anaeróbica, presença de microrganismos e condições do solo são considerados como fatores que interferem no processo que envolve a preservação ou não do cadáver. As circunstâncias que detêm a putrefação, uma vez iniciada, estão representadas pelos processos naturais conservadores dos cadáveres. A formação da adipocera foi investigada para confirmar a sua relação com o tempo de esqueletização relacionado ao sexo. O trabalho teve os seguintes objetivos: 1) registrar e comparar as variáveis ambientais temperatura, umidade relativa do ar, chuvas e as variáveis corporais peso e teor de gordura dos animais; 2) investigar se o processo de esqueletização sofre interferência hormonal, descrevendo, macroscopicamente, a esqueletização comparando-se os grupos conforme o sexo e a fase hormonal e 3) identificar a composição da massa cadavérica dos restos da decomposição corpórea através do método da cromatografia gasosa. Trata-se de trabalho experimental com ratos Wistar sendo utilizados 30 ratos divididos em três grupos: 10 machos castrados sem reposição de testosterona (MCST), 10 machos castrados com reposição de testosterona (MCCT) e 10 machos controles da testosterona (MCoT). Para a formação do grupo das fêmeas foram utilizadas 60 ratas divididas em seis grupos: 10 fêmeas controles na fase diestro (FCoD), 10 fêmeas controles na fase estro (FCoE), 10 fêmeas controles na fase proestro (FCoP), 10 fêmeas castradas sem reposição de hormônio (FCSH), 10 fêmeas castradas com reposição de estrógeno (FCCE) e 10 fêmeas castradas com reposição de progesterona (FCCP). Estes animais foram cuidados até atingirem o peso entre 350 e 450g, quando foram mortos em câmara de CO2 e depois envolvidos individualmente em gaze e algodão e colocados em urnas de madeira e depois sepultados dentro de uma caixa de cimento enterrada no solo. As análises realizadas para verificar a variação dos fatores ambientais e dos fatores corporais não interferiram no processo de esqueletização. Após as exumações, apenas o grupo MCoT apresentou esqueletização completa com o esqueleto visível livre de quaisquer restos remanescentes. Os grupos MCST e MCCT apresentaram esqueletização mínima com massa cadavérica recobrindo todo o corpo e alguns ainda apresentando órgãos e vísceras conservados. Todos os grupos das fêmeas apresentaram esqueletização parcial. Toda massa cadavérica analisada confirmou ser adipocera. Considerando-se que os dois grupos de animais foram sepultados no mesmo local, sob as mesmas condições ambientais e corporais, simultaneamente durante o mesmo intervalo de tempo, foi possível apontar a variável hormônio como o fator responsável pela diferença observada na decomposição corpórea.<br>Researches have been documenting as it is variable the corporal decomposition and the interval of time verified between the several phases of the process of decomposition of the corpse and the moment in which the death was verified. Environmental factors as temperature, humidity, aerobic and anaerobic conditions, presence of microorganisms and conditions of the soil are considered as factors that interfere in the process that involves the preservation or not of the corpse. The circumstances that stop the rotting, once initiated, are represented by the natural processes conservative of the corpses. The formation of the adipocere was investigated to confirm its relation to the time of skeletization related to the sex. The research had the following objectives: 1) to register and to compare the environmental temperature variables, relative humidity of the air, rain and the corporal weight variables and rate of fat of the animals; 2) to investigate if the skeletization process suffers hormonal interference, describing, macroscopically, the skeletization being compared to the groups according to the sex and the hormonal phase and 3) to identify the composition of the cadaverous mass of the remains of the corporal decomposition through the method of gas chromatography. It deals with experimental work with 30 Wistar rats divided into three groups: 10 castrated males no testosterone replacement (CMNT), 10 castrated males with testosterone replacement (CMWT) and 10 males control of testosterone (MCoT). For the formation of the group of the females, 60 female rats were used divided into six groups: 10 females control in the phase diestrus (FCoD), 10 females control in the phase estrus (FCoE), 10 females control in the phase proestrus (FCoP), 10 castrated females no hormone replacement (CFNH), 10 castrated females with estrogen replacement (CFWE) and 10 castrated females with progesterone replacement (CFWP). These animals were taken care of until they reached the weight between 350 and 450g, when they were killed in camera of CO2 and later involved individually in gauze and cotton and put in wood urns and later buried in a cement box placed in the soil. The analyses did to verify the variation of the environmental factors and of the corporal factors didn\'t interfere in the skeletization process. After the exhumations, just the group MCoT presented complete skeletization with the visible skeleton free from any remaining remains. The groups CMNT and CMWT presented minimum skeletization with cadaverous mass covering the whole body and some still presenting conserved organs and viscera. All of the groups of females presented partial skeletization. Every analyzed cadaverous mass was confirmed to be adipocere. Considering that the two groups of animals were buried in the same place, under the same environmental and corporal conditions, simultaneously during the same interval of time, it was possible to point out the variable hormone as the responsible factor for the difference observed in the corporal decomposition.

Decomposition chemistry refers to the biochemical degradation processes which occur in soft tissue as decomposition proceeds. This study aims to investigate the relationship between the release of decomposition fluids into contrasting soil environments and their potential correlation with the presence of a decomposing carcass. Soil from two different carcass decomposition trials was utilized to determine if seasonal and soil variation altered the soils reaction to a carcass. The reaction was determined by investigating the soil available phosphorus, extractable lipid-phosphate, pH, moisture and fatty acid content. A significant increase in the relative concentration of extractable lipid-phosphate, soil available phosphorus, and fatty acid content was identified, confirming the flux in the microbial biomass in the soil. Contrary to these nutrients, there were no notable changes in the soil pH and moisture content. The findings of this study were able to highlight the future forensic potential of these techniques and demonstrate a need for further research.

Postmortem interval (PMI) estimation is a necessary but often difficult task that must completed during a death investigation. The level of difficulty rises as time since death increases, especially with the case of skeletonized remains (long PMI). While challenging, a reliable PMI estimate may be of great importance for investigative direction and cost-savings (e.g. suspect identification, tailoring missing persons searches, non-forensic remains exclusion). Long PMI can be estimated by assessing changes in the organic content of bone (i.e. collagen), which degrades and is lost as the PMI lengthens. Visible-near infrared (VNIR) spectroscopy is one method that can be used for analyzing organic constituents, including proteins, in solid specimens. A 2013 preliminary investigation using a limited number of human cortical bone samples suggested that VNIR spectroscopy could provide a fast, reliable technique for assessing PMI in human skeletal remains. Clear separation was noted between "forensic" and "archaeological" specimen spectra within the near-infrared (NIR) bands. The goal of this research was to develop reliable multivariate classification models that could assign skeletal remains to appropriate PMI classes (e.g. "forensic" and "non-forensic"), based on NIR spectra collected from human cortical bone. Working with a large set of cortical samples (n=341), absorbance spectra were collected with an ASD/PANalytical LabSpec® 4 full range spectrometer. Sample spectra were then randomly assigned to training and test sets, where training set spectra were used to build internally cross-validated models in Camo Unscrambler® X 10.4; external validations of the models were then performed on test set spectra. Selected model algorithms included soft independent modeling of class analogy (SIMCA), linear discriminant analysis on principal components (LDA-PCA), and partial least squares discriminant analysis (PLSDA); an application of support vector machines on principal components (SVM-PCA) was attempted as well. Multivariate classification models were built using both raw and transformed spectra (standard normal variate, Savitzky-Golay) that were collected from the longitudinally cut cortical surfaces (Set A models) and the superficial cortical surface following light grinding (Set B models). SIMCA models were consistently the poorest performers, as were many of the SVM-PCA models; LDA-PCA models were generally the best performers for these data. Transformed-spectra model classification accuracies were generally the same or lower than corresponding raw spectral models. Set A models out-performed Set B counterparts in most cases; Set B models often yielded lower classification accuracy for older forensic and non-forensic spectra. A limited number of Set B transformed-spectra models out-performed the raw model counterparts, suggesting that these transformations may be removing scattering-related noise, leading to improvements in model accuracy. This study suggests that NIR spectroscopy may represent a reliable technique for assessing the PMI of unknown human skeletal remains. Future work will require identifying new sources of remains with established extended PMI values. Broadening the number of spectra collected from older forensic samples would allow for the determination of how many narrower potential PMI classes can be discriminated within the forensic time-frame.

Currently, forensic scientists are only able to determine time since death (or postmortem interval) up to the first 60 hours. This is based largely on insect activity. Herein, it is proposed to use the degradation of the intervertebral disc (IVD) after death to determine a relationship between the mechanical properties of cadaveric tissue and time since death in order to extend the 60-hour window. To that end, 1 fresh human spine and 6 pig spines were each separated into sections (6 human and 48 pig), with each section having one intact disc. The sections were buried, unearthed, and cleaned, leaving only the disc and bone. To determine the mechanical properties, each disc underwent three different tests: cyclic conditioning, compression, and stress relaxation testing. The Schapery collocation method was used to create a theoretical curve from the data for the experimental curve. Observations were made involving the corresponding k values of the curve. Although there are trends in the data for k values that approximate the experimental stress relaxation curve, a correlation could not be determined.<br>M.S.M.E.<br>Department of Mechanical, Materials and Aerospace Engineering;<br>Engineering and Computer Science<br>Mechanical Engineering

Em casos de investigação criminal, a determinação do tempo de morte pode inocentar ou culpar algum suspeito. Atualmente, os estudos publicados relacionados ao advento da autópsia virtual não consideram a possibilidade da utilização dos exames complementares de imagem como auxílio à estimativa do intervalo postmortem, sendo esta uma das principais motivações para a realização do presente estudo, já que a tomografia computadorizada é excelente método de medida de densidade. Diante desse cenário, o objetivo do trabalho foi aprimorar a estimativa do intervalo postmortem por meio da avaliação tomográfica das hipóstases viscerais torácicas. Foi realizado estudo prospectivo observacional com dados obtidos de 23 corpos de pacientes de ambos os sexos que foram encaminhados ao Serviço de Verificação de Óbitos da Capital São Paulo. Foram obtidos cortes tomográficos do segmento torácico de modo sequencial utilizando-se o tomógrafo SOMATOM® Emotion syngo CT 2012E, com intervalo de uma hora entre os exames, a fim de permitir a análise das modificações de densidade das hipóstases ao longo do tempo. Na janela de mediastino, foram selecionados os átrios direito e esquerdo para obtenção das medidas de densidade tecidual média. Foi possível concluir que a maioria das hipóstases pulmonares se estabiliza entre 8 e 12 horas e as hipóstases intracardíacas em torno de 12 horas. Além disso, o modelo estatístico de Mitscherlich pode ser utilizado para descrever o comportamento da hipóstase em função do intervalo de morte decorrido<br>In cases of criminal investigation, the determination of the time of death can acquit or condemn a suspect. Currently, the published studies related to the raising of the postmortem CT do not consider the possibility of using the complementary image exams as support to the estimate of the postmortem interval, being that one of the main motivations to the execution of the present study, once the multislice computed tomography is an excellent method of measure of density. In this scenery, the goal of this study was to improve the precision of the determination of the time of death through the tomographic evaluation of the visceral thoracic hypostasis. A prospective study was performed with data obtained from 23 bodies of patients, which were forward to the autopsy center of the city of São Paulo. Tomographic images of thorax were obtained sequentially, by using SOMATOM® Emotion syngo CT 2012E, with intervals of one hour each one between the exams, in order to allow the analysis of the modifications of the density of the hypostasis over time. In the mediastinum window, the right and left atrium were selected in order to obtain the measures of the average organ density. It was possible to conclude that the majority of the pulmonary hypostasis would stabilize between 8 and 12 hours and the intracardiac hypostasis around 12 hours. Furthermore, the statistical model of Mitscherlich can be used to describe the behavior of the images according to the postmortem interval

Studies were conducted on the effects of alcohol and opioids on the development of forensically important flies. In addition different methods of degree-day calculations and development thresholds were used to determine the effects on PMI estimates. The first study determined the effects of ethanol on the development of Phormia regina in vitro. Ground pork loin was treated with a 1, 5, or 10% ethanol solution to give an equivalent Blood Alcohol Concentration (BAC) of 0.01, 0.04, and 0.8 % w/v. A significant difference in the time for second instarsâ to complete the stage was seen between the 1% treated and control. Significant differences were also found among pupal and adult weights between all treatments and the control. A significant difference was shown between growth curves of the 5% treated and control for third instar larvae using the Kolmogorov-Smirnov test. The ethanol content of Phormia regina in migrating third instar larvae that fed on treated meat was examined using headspace-gas chromatography (HSGC). All larvae had a content of 0.01% w/v, including the control. The effects of ante-mortem injection of oxycodone in pigs were examined with respect to insect succession patterns and the development rates of Phormia regina. Pigs were given a subcutaneous injection of oxycodone hydrochloride (3 mg/kg by weight) and antemortem blood samples were collected prior to and following drug injection. Shortly after death the carcasses were placed at an open field site and allowed to decompose in a field cage. Insect samples were collected from carcasses for seven days post-mortem and the collected data were used to develop occurrence matrices. The Simple Matching Coefficient showed that successional patterns were similar between treated and untreated animals. Loin and liver from the carcasses were used as rearing media for in vitro development studies of Phormia regina. Kolmogorov-Smirnov test showed that third instar P. regina maggots from treated loin tissue were significantly longer in length than maggots feeding on untreated loin tissue. A significant difference in time was found among larvae on loin for the time from eclosion to completion of the second instar. Significant differences were seen in the weight of adults reared on liver and loin. A chi-square for homogeneity showed that adults were biased towards males (2:1) from untreated loin tissue. A final study compared weather data sources, Accumulated Degree-Day (ADD) methods, and postmortem interval (PMI) estimations based on threshold and developmental data source. Four pigs were used for statistical comparisons. Pigs were taken to a test site and allowed to decompose in an experimental cage. Probes recorded ambient temperatures and body temperatures. Maggot sampling was completed every day for each pig. A three way factorial linear fit model was used to test for statistical differences. Significant differences were seen in the calculated ADD based on probe location and the development threshold used. The ADD calculated from local weather station locations: Kentland Farm, Moore Farm, and Blacksburg Airport were also compared. A significant difference in ADD was found in the main effects among locations (Airport 44.1 ADD, Kentland 37.5 ADD, Moore 48.6 ADD), as well as among the thresholds used (10,12.2, and 14°C). Different PMI estimations also resulted when using development data from different development studies on Phormia regina.<br>Ph. D.

Forensic anthropologists rely on forensic evidence to estimate the postmortem interval of a decedent. This may include the study of the degree of deterioration of the human body, the life stage of insects, and the degradation of associated material evidence. Material evidence comes in many forms, and certain taphonomic processes will affect the material and must be considered when making inferences about a PMI. These include variables such as the characteristics of the soil, microorganisms, and the presence of a decaying organic material. Previous research has undertaken studies in how fabric degrades over time; however, there is no standard methodology in use. The purpose of this research project is to establish a comprehensive scoring system and description standard after analyzing the degradation of four different fabric types. This will be useful for future studies in need of a standard methodology. In addition, the methods used in this project can be applied to actual forensic cases. After retrieval, the fabric type with the highest degradation was the cotton with about 1/3 of all cotton fabric swatches demonstrating more than 50% total degradation. For all fabric types, swatches that were positioned flat tended to degrade more than those that were positioned crumpled. Cotton fabric swatches degraded more in Trench 1 and Trench 2 than the Ground Surface, however, all other fabric types demonstrated slightly more degradation on the Ground Surface than the other two Areas. Soil moisture fluctuated the most on the Ground Surface while Trench 1 and Trench 2 were able to retain more water in the soil. Overall, cotton was the only fabric type to degrade significantly enough to show how it degrades over time, while the other fabric types have longer degradation intervals that must be studied further.<br>B.A.<br>Bachelors<br>Sciences<br>Anthropology