Postmortem Interval Estimation Using Protein Chip Technology Combined with Multivariate Analysis Methods / 法医学杂志

OBJECTIVES@#To estimate postmortem interval (PMI) by analyzing the protein changes in skeletal muscle tissues with the protein chip technology combined with multivariate analysis methods.@*METHODS@#Rats were sacrificed for cervical dislocation and placed at 16 ℃. Water-soluble proteins in skeletal muscles were extracted at 10 time points (0 d, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, 7 d, 8 d and 9 d) after death. Protein expression profile data with relative molecular mass of 14 000-230 000 were obtained. Principal component analysis (PCA) and orthogonal partial least squares (OPLS) were used for data analysis. Fisher discriminant model and back propagation (BP) neural network model were constructed to classify and preliminarily estimate the PMI. In addition, the protein expression profiles data of human skeletal muscles at different time points after death were collected, and the relationship between them and PMI was analyzed by heat map and cluster analysis.@*RESULTS@#The protein peak of rat skeletal muscle changed with PMI. The result of PCA combined with OPLS discriminant analysis showed statistical significance in groups with different time points (P<0.05) except 6 d, 7 d and 8 d after death. By Fisher discriminant analysis, the accuracy of internal cross-validation was 71.4% and the accuracy of external validation was 66.7%. The BP neural network model classification and preliminary estimation results showed the accuracy of internal cross-validation was 98.2%, and the accuracy of external validation was 95.8%. There was a significant difference in protein expression between 4 d and 25 h after death by the cluster analysis of the human skeletal muscle samples.@*CONCLUSIONS@#The protein chip technology can quickly, accurately and repeatedly obtain water-soluble protein expression profiles in rats' and human skeletal muscles with the relative molecular mass of 14 000-230 000 at different time points postmortem. The establishment of multiple PMI estimation models based on multivariate analysis can provide a new idea and method for PMI estimation.

Research Progress on Estimation of Postmortem Interval Based on Ocular Tissues Structure / 法医学杂志

Estimation of postmortem interval (PMI) is one of the important research contents in forensic pathology, and it has always been the focus and hot spot of research work. In recent years, scholars at home and abroad have made some research progress in estimating PMI by using ocular tissue. After death, the changes of cornea, aqueous humor, iris, lens, vitreous humor and retina all show time sequence change rule highly related to PMI. This paper reviews the research progress of PMI estimation based on the morphological, biochemical, molecular and genetic material changes of different ocular tissue structures after death, and discusses the existing problems and development trends.

Changes of 1, 5-AG in Vitreous Humor of Rabbit Cadavers with Hyperglycemic Metabolism / 法医学杂志

OBJECTIVES@#To investigate the concentration and change characteristics of 1, 5-anhydroglucitol (1, 5-AG) in the vitreous humor of rabbit cadavers with hyperglycemic metabolism, and to explore the value of 1, 5-AG in forensic pathology identification of death caused by hyperglycemic metabolism disorders.@*METHODS@#A diabetic hyperglycemic rabbit model was established by using alloxan. Eighteen rabbits with fasting glucose concentration ≥13.80 mmol/L (experimental group) and 18 healthy rabbits with fasting glucose concentration ≤6.10 mmol/L (control group) were selected. After death from air embolism. The blood samples were collected immediately, and vitreous humor samples were collected at 0 h, 12 h, 24 h and 36 h after death. The concentration of 1, 5-AG in the blood and vitreous humor of rabbits was determined.@*RESULTS@#The blood glucose concentration in the experimental group was (25.10±3.14) mmol/L. At the time of death, there was no significant difference in the concentration of 1, 5-AG in the blood [(0.94±0.20) μg/mL] and in the vitreous humor (0.99±0.05 μg/mL, P>0.05). The concentration of 1, 5-AG in the vitreous humor of the experimental group was lower than that of the corresponding control group at all time points (P<0.05), and there was no significant difference betwwen 1, 5-AG concentration in vitreous humor between earch time point in the experimental group and the control group (P>0.05). Correlation analysis showed that the concentration of 1,5-AG in blood was negatively correlated with blood glucose in both control group and experimental group (control group: r=-0.79, P<0.05; experimental group: r=-0.97, P<0.05).@*CONCLUSIONS@#Vitreous humor can replace blood as an effective test sample for 1,5-AG detection. The concentration of 1, 5-AG in rabbit vitreous humor remains stable within 36 hours after death and is not affected by the change of postmortem interval. If the concentration of 1, 5-AG decreases significantly, it indicates the existence of hyperglycemia in rabbits before death.

Aspectos clínicos y forenses del color rosa de los dientes: reporte de un caso / Clinical and forensic aspects of the pink color of teeth: report of a case

La coloración rosa de los dientes puede originarse por diferentes factores. En el ámbito forense se ha descrito al fenómeno denominado post mortem pink teeth como un signo asociado a muertes violentas de etiología diversa. En la práctica clínica también es posible observar pacientes con dientes rosados, fre-cuentemente ocasionados por traumatismos o iatro-genia proveniente de ortodoncia, cuyo mecanismo de producción obedece a distintas etiopatogenias, destacándose las reabsorciones dentinarias inter-nas, cemento-dentinarias externas y calcificaciones dentinarias. El presente artículo expone el caso de un individuo adulto con antecedente de trauma óseo-dentario por accidente vial que, luego de un prolon-gado tiempo, asiste al Servicio de Urgencias Odon-tológicas y Orientación de Pacientes de la Facultad de Odontología de la Universidad de Buenos Aires, en donde se le detecta, a modo de hallazgo exploratorio, una ostensible coloración rosada en el canino infe-rior derecho. La situación motivó un pormenorizado abordaje clínico y radiográfico, indagando respecto a los probables factores que intervinieron en su ge-neración y desarrollo (AU)

The pink coloration of the teeth can be caused by dif-ferent factors. In the forensic field, the phenomenon called post mortem pink teeth has been described as a sign associated with violent deaths of various etiology. In clinical practice, it is also possible to ob-serve patients with pink teeth, frequently caused by trauma or iatrogenesis from orthodontics, whose production mechanism is due to different etiopatho-genesis, highlighting internal dentin resorption, ex-ternal cemento-dentinal resorption and dentin calci-fications. This article presents the case of an adult individual with a history of bone-dental trauma due to a road accident who, after a long time, attends the Dental Emergency and Patient Guidance Service of the Faculty of Dentistry of the University of Bue-nos Aires, where an ostensible pink coloration was detected in the lower right canine as an exploratory finding. The situation motivated a detailed clinical and radiographic approach, inquiring about the probable factors that intervened in its generation and development (AU)

¿Es el "diente rosado" válido en el contexto forense actual? / Are "pink teeth" relevant to current forensics?

Introducción: El "diente rosado" es un fenómeno post mortem. Se caracteriza por una tonalidad rosa, rojiza y hasta púrpura, que puede observarse en los dientes. Su primera referencia se remite a 1829, cuando Thomas Bell lo describió, y genera polémica desde hace casi dos siglos. La temática plantea varias interrogantes: ¿sería más lógico nombrarlo "red teeth" o "purple teeth"?, ¿qué provoca esa tonalidad más intensa?, ¿la coloración rosada indica determinada causa de muerte?, ¿queda para siempre o puede desaparecer por diversos factores? Objetivo: Describir los indicadores de que el "diente rosado" o "pink teeth" pueda aún ser considerado un elemento importante para la investigación forense actual. Comentarios principales: Luego de la experiencia acumulada con los casos trabajados durante los últimos 20 años y la revisión bibliográfica realizada, se evidencia que el fenómeno aparece sobre todo en las piezas dentales anteriores y premolares monorradiculares. Además, puede verse tanto ante mortem como post mortem. Por causas diferentes el post mortem necesita de varios días para instaurarse y es un evento tafonómico, evidenciable tanto en muertes violentas como naturales, aunque la variación en su tonalidad depende de diversos factores. Consideraciones globales: Teniendo en cuenta la experiencia obtenida por los autores, y lo referido en la bibliografía sobre el tema, se evidencia que este signo, fenómeno o hallazgo (al aclararse las interrogantes planteadas) aún puede ser muy significativo y orientador en el contexto forense actual(AU)

Introduction: "Pink teeth" are a post-mortem phenomenon characterized by a rose, reddish and even purple shade of color which may be observed in teeth. Their first reference dates back to 1829, when Thomas Bell described them. They have been a topic of debate for almost two centuries. The subject poses several questions: Would it be more logical to name them "red teeth" or "purple teeth"? What causes the increase in color intensity? Does the pink shade signal a specific cause of death? Does it remain forever or may it disappear for a variety of reasons? Objective: Describe the indicators that "pink teeth" may still be considered an important element in current forensic research. Main remarks: Based on the experience gathered from the cases analyzed in the last 20 years and the bibliographic review conducted, it is evident that the phenomenon appears mainly in anterior teeth and single-rooted premolars. On the other hand, pink teeth may be observed ante mortem as well as post mortem. For a number of reasons, post mortem pink teeth take several days to form, and they are a taphonomic phenomenon, present in violent as well as natural deaths, though their change in tone depends on various factors. General considerations: Founded on the experience obtained by the authors and the bibliography about the topic, it is evident that this sign, phenomenon or finding (upon clarification of the questions posed) may still be very significant and enlightening in the current forensic context(AU)

Research Progress of DNA-Based Technologies for Postmortem Interval Estimation / 法医学杂志

In criminal investigations, postmortem interval (PMI) is important information to be inferred in homicide investigations, as well as the focus and the difficulty in forensic pathology research. Because the DNA content in different tissues is relatively constant and shows changes regularly with the extension of PMI, it has become a research hotspot of PMI estimation. This paper reviews the recent progress of PMI estimation technologies including DNA-based single cell gel electrophoresis, image analysis, flow cytometry, real-time fluorescence quantitative PCR and high-throughput sequencing, hoping to provide references for forensic medicine practice and scientific research.

New Advances, Challenges and Opportunities in Forensic Applications of Microbiomics / 法医学杂志

The succession of microbiota is closely associated with several essential factors, including race, sex, health condition, lifestyle, postmortem interval, etc., and it has great potential application value in forensic medicine. This paper summarizes recent studies on the forensic applications of the microbiome, including individual identification, geographical feature identification, origin identification of the tissue or body fluid, and postmortem interval estimation, and introduces the current machine learning algorithms for microbiology research based on next-generation sequencing data. In addition, the current problems facing forensic microbiomics such as the extraction and preservation of samples, construction of standardization and database, ethical review and practical applicability are discussed. Future multi-omics studies are expected to explore micro ecosystems from a comprehensive and dynamic perspective, to promote the development of forensic microbiomics application.

Postmortem Distribution and Postmortem Redistribution of Carbofuran-7-Phenyl Glucuronic Acid in Rabbits / 法医学杂志

OBJECTIVES@#To establish a carbofuran intragastric administration death model in rabbits, and to observe the postmortem distribution and postmortem redistribution of carbofuran-7-phenyl glucuronic acid (Glu-7PH) in rabbits.@*METHODS@#The postmortem distribution: Rabbits were given an administration of 1/2LD50, LD50, 2LD50 carbofuran. Dead rabbits were dissected immediately. Rabbits that had remained alive 2 hours were sacrificed by carbon dioxide (CO2) inhalation and dissected immediately. The myocardium, cardiac blood, liver, spleen, lung, kidney, brain and right hindlimb muscle were collected. The postmortem redistribution: After giving an administration of 4LD50 carbofuran, the myocardium, cardiac blood, liver, spleen, lung, kidney, brain, and right hindlimb muscle were collected at 0, 12, 24, 48, and 72 h postmortem in supine position at 15 ℃ room temperature. The quantity of Glu-7PH was determined by LC-MS/MS.@*RESULTS@#The postmortem distribution: Among the three dose groups, there were significant differences in the quantities of Glu-7PH in different tissues. The postmortem redistribution: There was no significant difference in the Glu-7PH quantities in cardiac blood, mycardium, spleen, kidney, brain and right hindlimb muscle, but there was a significant difference in the Glu-7PH quantities in the liver and lung.@*CONCLUSIONS@#The mycardium, cardiac blood, liver, lung, kidney, brain and hindlimb muscle of rabbits can be used as appropriate samples for Glu-7PH detection. However, it should be noted that Glu-7PH was redistributed postmortem in rabbit liver and lung.

Application of Linear Regression Model of Gpnmb Gene in Rat Injury Time Estimation / 法医学杂志

OBJECTIVES@#To investigate the effects of injury time, postmortem interval (PMI) and postmortem storage temperature on mRNA expression of glycoprotein non-metastatic melanoma protein B (Gpnmb), and to establish a linear regression model between Gpnmb mRNA expression and injury time, to provide aimed at providing potential indexes for injury time estimation.@*METHODS@#Test group SD rats were anesthetized and subjected to blunt contusion and randomly divided into 0 h, 4 h, 8 h, 12 h, 16 h, 20 h and 24 h groups after injury, with 18 rats in each group. After cervical dislocation, 6 rats in each group were collected and stored at 0 ℃, 16 ℃ and 26 ℃, respectively. The muscle tissue samples of quadriceps femoris injury were collected at 0 h, 12 h and 24 h postmortem at the same temperature. The grouping method and treatment method of the rats in the validation group were the same as above. The expression of Gpnmb mRNA in rat skeletal muscle was detected by RT-qPCR. The Pearson correlation coefficient was used to evaluate the correlation between Gpnmb mRNA expression and injury time, PMI, and postmortem storage temperature. SPSS 25.0 software was used to construct a linear regression model, and the validation group data was used for the back-substitution test.@*RESULTS@#The expression of Gpnmb mRNA continued to increase with the prolongation of injury time, and the expression level was highly correlated with injury time (P<0.05), but had little correlation with PMI and postmortem storage temperature (P>0.05). The linear regression equation between injury time (y) and Gpnmb mRNA relative expression (x) was y=0.611 x+4.489. The back-substitution test proved that the prediction of the model was accurate.@*CONCLUSIONS@#The expression of Gpnmb mRNA is almost not affected by the PMI and postmortem storage temperature, but is mainly related to the time of injury. Therefore, a linear regression model can be established to infer the time of injury.

Research Progress of Forensic Diagnosis Approaches of Early Acute Myocardial Infarction / 法医学杂志

The postmortem diagnosis of acute myocardial infarction (AMI), especially the postmortem diagnosis of early AMI that died immediately after onset or within 1 hour, has always been a difficulty in forensic identification. This article reviews the forensic application of diagnosis and analysis methods for AMI postmortem diagnosis including autopsy imaging, histomorphology, immunohisto-chemistry, biochemical marker and molecular biology diagnosis, and explores the feasible scheme of early postmortem diagnosis in AMI.

Relationship between Water Temperature and Floating Time of Aquatic Cadavers / 法医学杂志

OBJECTIVES@#To study the relationship between water temperature and floating time of aquatic cadavers, providing a reference for more precise positioning and searching for floating corpses.@*METHODS@#The floating model of guinea pig after drowning at 17-30 ℃ was established, and the floating times of carcasses were recorded. The collected data of 32 floating corpse cases in the Pearl River were sorted out and analyzed according to the floating time of corpses corresponding to each degree of water temperature. The relationship models between water temperature and the floating time of guinea pig carcass, and between that and the floating time of real cases were established.@*RESULTS@#The floating time of the cadaver was negatively correlated with water temperature. The power function fitting equation of the relationship between floating time and water temperature of guinea pig carcass was y=1×1015x-10.530(R2=0.871, P<0.01), and the power function fitting equation of the relationship between corpse floating time and water temperature was y=3×106x-3.467(R2=0.802, P<0.01).@*CONCLUSIONS@#It is found that average floating cadaver time has a power function with water temperature, which provides a reference for locating floating cadavers and establishing search models.

Inferring Postmortem Submersion Interval in Rats Found in Water Based on Vitreous Humor Metabolites / 法医学杂志

OBJECTIVES@#The metabolomics technique of LC-MS/MS combined with data analysis was used to detect changes and differences in metabolic profiles in the vitreous humor of early rat carcasses found in water, and to explore the feasibility of its use for early postmortem submersion interval (PMSI) estimation and the cause of death determination.@*METHODS@#The experimental model was established in natural lake water with 100 SD rats were randomly divided into a drowning group (n=50) and a postmortem (CO2 suffocation) immediately submersion group (n=50). Vitreous humor was extracted from 10 rats in each group at 0, 6, 12, 18 and 24 h postmortem for metabolomics analyses, of which 8 were used as the training set to build the model, and 2 were used as test set. PCA and PLS multivariate statistical analysis were performed to explore the differences in metabolic profiles among PMSI and causes of death in the training set samples. Then random forest (RF) algorithm was used to screen several biomarkers to establish a model.@*RESULTS@#PCA and PLS analysis showed that the metabolic profiles had time regularity, but no differences were found among different causes of death. Thirteen small molecule biomarkers with good temporal correlation were selected by RF algorithm. A simple PMSI estimation model was constructed based on this indicator set, and the data of the test samples showed the mean absolute error (MAE) of the model was 0.847 h.@*CONCLUSIONS@#The 13 metabolic markers screened in the vitreous humor of rat corpses in water had good correlations with the early PMSI. The simplified PMSI estimation model constructed by RF can be used to estimate the PMSI. Additionally, the metabolic profiles of vitreous humor cannot be used for early identification of cause of death in water carcasses.

Aspectos médico-legais do olho / Medicolegal aspects of the eye

RESUMO A oftalmologia fornece um campo vasto de conhecimentos necessários à medicina legal e às perícias médicas. O presente artigo objetivou revisar as informações na perícia criminal e cível, as repercussões da morte e os achados post-mortem que o exame ocular pode fornecer. Demonstrou-se que a perícia ocular é complexa e multifacetada, fornecendo ferramentas importantes para a classificação das lesões corporais, verificação da capacidade laboral, investigação da causa mortis e estimativa do tempo de morte.

ABSTRACT Ophthalmology provides a vast field of knowledge necessary for forensic medicine and medical expertise. The present article aimed to review the information on criminal and civil medical expertise, the repercussions of death, and the postmortem findings that the eye examination can provide. Ocular expertise has been shown to be complex and multifaceted, providing important tools to classify bodily injuries, verify work capacity, investigate the cause of death, and estimate the time of death.

Consentimiento informado en la toma de muestras postmortem: revisión bibliográfica / Informed consent of postmortem sampling: Bibliographic review

Justificación: el consentimiento informado, se fundamenta en el principio de autonomía de las personas, la concepción moral sobre el respeto de la dignidad del ser humano y por tanto en su libertad. En el consentimiento informado se articulan el resto de los principios bioéticos universales: la no maleficencia, la justicia, y la beneficencia. Objetivo: Establecer las situaciones en las cuales es pertinente aplicar el consentimiento informado en la toma de muestras postmortem desde un enfoque bioético versus un enfoque legal. Metodología: se realizó una revisión en: Scielo, LILACS, IBECS, CUMED, NIH, Repositorio de la Organización Panamericana de la Salud; usando palabras clave: consentimiento informado, derechos humanos, autonomía, bioética, autopsia, muestras postmortem y médicos forenses y combinaciones de estas. Los criterios de inclusión: artículos con antigüedad máxima de cinco años, en español e inglés de libre acceso. Resultados: se obtuvieron 113 artículos utilizando las palabras clave y sus combinaciones, más otros 43 registros adicionales identificados de otras fuentes como leyes, reglamentos etc. Al eliminar las fuentes: duplicadas, no relevantes, inhabilitadas e incompletas se trabajó con un total de 49 artículos. Conclusiones: existe la necesidad de incluir en las pautas éticas nacionales e internacionales que regulan la investigación científica, lineamientos a seguir sobre la realización del proceso del consentimiento informado en los estudios que involucren muestras postmortem, utilizadas posteriormente a su uso primario...(AU)

Cambios histológicos del tejido muscular estriado lingual en ratas Sprague Dawley (Rattus norvegicus) para estimar el intervalo postmortem / Histological changes of lingual striated muscle tissue in Sprague Dawley rats (Rattus norvegicus) for estimating the postmortem interval

RESUMEN: El intervalo postmortem (IPM) equivale al tiempo que ha transcurrido desde que un ser humano ha muerto hasta su examinación postmortem. Después de la muerte, el cuerpo experimenta modificaciones en su composición física y química denominados cambios postmortem expresados por signos que pueden ser analizados para el cálculo del IPM. El objetivo del estudio fue describir los cambios histológicos presentes en la musculatura estriada lingual de rata en diferentes IPM. Se utilizaron 10 ratas machos Sprague dawley de dos meses de edad. Los animales fueron eutanasiados y dejados a temperatura ambiente (4 - 14 ?C) para tomar muestras de la lengua a distintos IPM (0, 6, 12, 24, 48, 72, 96 y 120 horas postmortem). El estudio se llevó a cabo considerando las recomendaciones de la Guía para el Cuidado y Uso de Animales de Laboratorio. Las muestras fueron fijadas en formaldehido tamponado a 10 % y procesadas para su inclusión en paraplast. Se realizaron cortes de 5 μm de grosor y fueron teñidas con HE para su análisis con microscopía óptica. Los cambios histológicos en las células musculares estriadas de la lengua estaban asociados a los distintos IPM. A las 6 horas postmortem, hubo cambios iniciales en la morfología nuclear y su pigmentación. A las 12 y 24 horas postmortem, se observaron cambios en las estrías musculares y aumento en el número de casos con alteraciones nucleares. A las 48 y 72 horas postmortem, eran evidentes las vacuolas citoplasmáticas, cambios en la coloración de las miofibras y aumento en las alteraciones nucleares. A las 92 y 120 horas postmortem, se observó disminución de las estrías musculares y núcleos celulares. Los núcleos eran picnóticos y puntiformes; hubo pérdida de la morfología celular y presencia de musculo liso. En conclusión, los cambios de la histología del músculo estriado lingual de rata permiten estimar el IPM. Este modelo podría ser aplicable a la medicina forense.

SUMMARY: The postmortem interval (PMI) equals the time that has elapsed since a human being has died until his postmortem examination. After death, the body experiences modifications in its physical and chemical composition know as postmortem changes expressed by signs that can be analyzed for the calculation of the MPI. The aim of the study was to describe the histological changes present in rat lingual striated musculature in different PMIs. 10 two-month-old male Sprague dawley rats were used. The animals were euthanized and left at room temperature (4-14 ?C) to sample the tongue at different PMIs (0, 6, 12, 24, 48, 72, 96 and 120 hours postmortem). The study was carried out considering the recommendations of the Guide for the Care and Use of Laboratory Animals. The samples were fixed in 10% buffered formaldehyde and processed for inclusion in paraplast. 5 μm thick sections were made and stained with HE for análisis with light microscopy. Histological changes in the striated muscle cells of the tongue were associated with the different PMIs. At 6 hours postmortem, there were initial changes in nuclear morphology and its pigmentation. At 12 and 24 hours postmortem, changes in muscle striae and an increase in the number of cases with nuclear alterations were observed. At 48 and 72 hours postmortem, cytoplasmic vacuoles, changes in myofiber coloration, and increased nuclear alterations were evident. At 92 and 120 hours postmortem, a decrease in muscle striae and cell nuclei was observed. The nuclei were pyknotic and pinpoint; there was loss of cell morphology and presence of smooth muscle. In conclusion, changes in the histology of rat lingual skeletal muscle make it possible to estimate MPI. This model could be applicable to forensic medicine.

Correlación entre sodio, cloro y potasio del cuerpo vítreo y el intervalo postmortem sobre los 2. 850 msnm / Correlation between sodium, chlorine and potassium of the vitreous body and the postmortem interval above 2. 850 msnm

RESUMEN: El intervalo Postmortem (IPM) es un importante desafío por resolver en la patología forense, y consiste en poder determinar el tiempo transcurrido desde la muerte hasta el momento de la autopsia. Dada la poca confiabilidad de algunos métodos por la gran influencia de factores externos y propios del cadáver, la bioquímica forense ha recibido considerable atención por sus niveles de seguridad. La ciudad de Quito se ubica en la cordillera de Los Andes a 2850 msnm, sin embargo, en la literatura no existen reportes de medición de estos parámetros a una altura como ésta. El objetivo fue establecer una correlación entre sodio (Na+), cloro (Cl-) y potasio (K+) del humor vítreo del cuerpo vítreo y el IPM a la altura de la ciudad de Quito. Para el estudio se utilizaron 128 muestras de cuerpo vítreo provenientes de 16 autopsias practicadas en la Unidad de Medicina Legal Zona 9, en IPM de 6, 12, 24, 48, 72, 96, 120 y 144 horas. Para la obtención del humor vítreo se siguió el método convencional, se dividió para las 8 alícuotas y se llevó a congelación -20 °C hasta el momento de su análisis. La cuantificación de la concentración de electrolitos Na+, Cl- y Potasio+ se realizó mediante analizador ISE de Roche Cobas (Roche Diagnostics) C501, calibrado para uroanálisis, y no fue necesaria la dilución. Durante la calibración y cada tres muestras, se midió un estándar interno para corregir los efectos de la desviación sistemática en la calibración. El enfoque estadístico se basó en un análisis de correlación lineal, utilizando el coeficiente de correlación de Spearman. La correlación entre las horas postmortem y las concentraciones de los diferentes electrolitos, fueron estadísticamente significativas. Se pudo corroborar una correlación lineal significativa entre el IPM y el aumento del K+ en el HV.

SUMMARY: The postmortem interval (PMI) is an important challenge to be solved in forensic pathology, and it consists of being able to determine the time elapsed from death to the moment of autopsy. Given the unreliability of some methods due to the great influence of external factors and those specific to the corpse, forensic biochemistry has received considerable attention for its levels of safety. The city of Quito is located in the Andes mountain range at 2850 meters above sea level, however, in the literature there are no reports of measurement of these parameters at a height like this. The objective was to establish a correlation between sodium (Na+), chlorine (Cl-) and potassium (K+) of the vitreous humor and the MPI at a height of 2,850 masl. For the study, 128 samples of vitreous humor were used from 16 autopsies performed in the Zone 9 Legal Medicine Unit, in IPM of 6, 12, 24, 48, 72, 96, 120 and 144 hours. To obtain the vitreous humor, the conventional method was followed, it was divided for the 8 aliquots and it was frozen at -20 ° C until the moment of its analysis. The quantification of the concentration of electrolytes Na+, Cl- and K+ was carried out using an ISE analyzer from Roche Cobas (Roche Diagnostics) C501, calibrated for urinalysis, and no dilution was necessary. During calibration and every third sample, an internal standard was measured to correct for the effects of systematic deviation on the calibration. The statistical approach was based on a linear correlation analysis, using the Spearman correlation coefficient. The correlation between the postmortem hours and the concentrations of the different electrolytes were statistically significant. A significant linear correlation between the PMI and the increase in K+ in vitreous humor could be corroborated.

Application of CD83 and HSF5 to Identify Antemortem and Postmortem Skin Burns / 法医学杂志

OBJECTIVES@#To explore the forensic application value of cluster of differentiation 83 (CD83) and heat shock transcription factor 5(HSF5) in identifying antemortem and postmortem skin burns.@*METHODS@#Through reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR), CD83 and HSF5 mRNA levels in the skin tissues of antemortem and postmortem burned mice and human samples were detected quantitatively.@*RESULTS@#Compared with the control group and the postmortem burned group, the mRNA levels of CD83 and HSF5 in antemortem burned mice were higher. The high mRNA expressions of CD83 could be detected 96 h after death, and the mRNA expressions of HSF5 could be observed 72 h after death. Compared with undamaged skin, increased CD83 and HSF5 mRNA levels were detected in 11 out of 15 cases(P<0.05).@*CONCLUSIONS@#CD83 and HSF5 can be used in forensic practice as indicators for vital reaction in antemortem burn identification.

Research Progress on Accumulated Degree Days for PMI Estimation / 法医学杂志

Among many factors that affect postmortem interval （PMI）, temperature is undoubtedly the most important factor, but simply considering temperature in estimation of PMI has limitations. Accumulated degree days （ADD） is an important indicator related to biological growth and development, which considers two major variables, environmental temperature and elapsed time. Therefore, the establishment of mathematical model of ADD and some evaluation indicators to estimate PMI, is obviously better than single temperature variable. This article briefly describes the research history of ADD, its application in PMI estimation, and the problems it faces, to provide reference for the further development of ADD to improve the accuracy of PMI estimation.

Application of Sarcosaprophagous Insects to Estimate the Postmortem Interval in 11 Cases / 法医学杂志

Objective To test the feasibility and accuracy of with sarcosaprophagous insects postmortem interval （PMI） estimation with sarcosaprophagous insects and provide references for estimation practice. Methods Eleven cases confirmed by the detection results, with complete entomological evidence were selected. The insect species, estimation results and true results involved in the cases were statistically analyzed and compared. Results Thirteen species of insects were found at the criminal scene, including Chrysomya megacephala （Fabricius）, Chrysomya rufifacies （Macquart）, Chrysomya nigripes （Aubertin）, Lucilia sericata （Meigen）, Hydrotaea spinigera Stein, Muscina stabulans （Fallén）, Sarcophagid （species were not identified）, Megaselia scalaris （Loew）, Hermetia illucens （Linnaeus）, Saprinus splendens （Paykull）, Creophilus maxillosus （Linnaeus）, Dermestes maculatus （De Geer） and Necrobia ruficollis （Fabricius）. The PMI of all eleven cases was within the range of estimated PMI. The estimated results of 72.73% cases were on the same day of the true results. Conclusion Sarcosaprophagous insects can estimate the PMI simply and conveniently. In cases where the PMI is within the time range of one generation of flies or beetles, the estimation results are relatively accurate. However, the estimation is less accurate when the PMI is beyond the time range.

Research Progress on Species Identification of Sarcosaprophagous Flies / 法医学杂志

Estimation of postmortem interval （PMI） has always been one of the difficult problems for forensic scientists. It is especially hard to estimate the PMI of highly decomposed corpses in the wild or in secluded houses with conventional methods. Therefore, application of insect evidence at the scene is usually required for estimation. Sarcosaprophagous flies of different species have totally different developmental rates. In actual cases, direct measurement of the body length of the larvae, calculation of accumulated temperature and succession stages without species identification, or calculation based on incorrect species identification would often lead to a large deviation between the calculated results and the real PMI. This mistake would also mislead the case investigation. Therefore, accurate species identification should be implemented before any PMI estimation of decomposed corpses with forensic entomological methods. This article reviews the general and ultramicroscopic species identification and molecular biological species identification methods of different stages of sarcosaprophagous flies, in order to provide new ideas and methods for related research and practice, and provide reference for the application and promotion of forensic entomology in the front line of public security.