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.

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.

Effect of thiamethoxam (organophosphate) on the flies and beetle visitation and cadaveric decomposition process

ABSTRACT Entomofauna associated with decaying cadavers may be useful in criminal investigation, either through the development of immature insects of interest or through entomological succession in corpses. These factors may vary if the insects are exposed to toxic substances that can modify the insect's developmental cycle, as well as its own occurrence, which would imply significant changes in the results of any investigation. However, there are few studies on how contamination by toxic compounds can affect the action of insects on carcasses and their consequence for forensic expertise. Therefore, this study aimed to test the hypothesis that the normal visitation of flies and beetles is altered in insecticide-contaminated carcasses. The experiment was carried out in a sugarcane plantation, using pig carcasses contaminated with insecticide and the same number of carcasses without any type of contamination as a control. In all experiments, the contaminated carcasses reached the final phase of decomposition in a longer time than the uncontaminated carcasses of the control group. A total of 2.767 specimens were collected and identified, 2.103 individuals from the order Diptera and 664 from the order Coleoptera. There was a significant geometric regression adjustment during the decomposition phases only for the control group, different from the contaminated carcasses in which this pattern did not occur. Results show that contamination by insecticide alters decomposition time and phase, altering the action of flies and beetles, affecting the abundance, composition of species as well as their activities, which can alter the data used by experts in criminal experts.

Research Progress of Exosomes and Their Forensic Significance / 法医学杂志

Exosomes are membranous tiny vesicles secreted by cells, which are widely found in the extracellular matrix and various body fluids and carry a variety of biologically functional molecules such as proteins, lipids, messenger RNA (mRNA) and microRNA (miRNA). Exosomes not only play important biological roles in the field of immunology and oncology, but also have potential application value in the field of forensic medicine. This article reviews the discovery, production and degeneration mechanism, biological functions, isolation and identification methods of exosomes, summarizes the research on exosomes and their significance in the field of forensic science, and discusses their applications in body fluid identification, individual identification, postmortem interval estimation to provide ideas for the application of exosomes in forensic work.

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.

Visualization of Literature Information on Postmortem Interval Estimation Indexed by CNKI Database from 1990 to 2020 / 法医学杂志

OBJECTIVES@#To explore the development process of the postmortem interval (PMI) research in China from January 1990 to August 2020, research hotspots in different periods, authors and cooperation between institutions, and to provide a reference for the better development of PMI inference research through the visualization of the literature information of the PMI estimation research indexed in China National Knowledge Infrastructure (CNKI).@*METHODS@#The information visualization analysis software CiteSpace 5.7.R1 was used to carry out big data analysis on hotspots, high-frequency keywords, authors, institutions and other information in the research literature on PMI inference from January 1990 to August 2020 indexed in CNKI.@*RESULTS@#The peak time of publication of PMI was from 2006 to 2010 with 114 articles. In keyword co-occurrence network, the effective hot words were forensic entomology, DNA content analysis and some emerging words such as artificial intelligence and big data. In the cooperation network of institutions, the high-frequency institutions were mainly the scientific research institutions. The author cooperation network showed a trend of co-aggregation and multi-cooperation.@*CONCLUSIONS@#With the development of science and technology, the research on PMI estimation based on traditional methods is mature and novel strategies are emerging. Big data and artificial intelligence combined with forensic science provide new research directions on PMI estimation.

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.

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 Postmortem Biochemistry Analysis in Forensic Medicine / 法医学杂志

In recent years, postmortem biochemistry analysis has gradually been applied to forensic practice, providing objective evidence for health conditions before death, disease pathophysiological processes and forensic diagnosis of postmortem interval and cause of death. It is of great significance to understand the change patterns of postmortem biochemical indicators and their applications in forensic medicine. This article reviews the research progress of postmortem biochemistry and its application in forensic medicine, it summarizes the existing problems of postmortem biochemistry analysis in forensic medicine of China and discusses the application prospect of postmortem biochemistry analysis in forensic medicine. This review is expected to provide references for forensic practitioners.

Research Progress on Developmental Biology of Sarcosaprophagous Insects / 法医学杂志

Forensic entomology provides a feasible way to estimate postmortem interval (PMI), of which the growth and development of sarcosaprophagous insects is the most widely used indicator in forensic practice. Over the years, forensic entomologists have carried out a large number of studies on the development biology of sarcosaprophagous insects. This paper illustrates the main factors that affect the development of sarcosaprophagous insects, including temperature, humidity, light, food types and poisons. The development indicators of sarcosaprophagous insects were reviewed from the perspectives of morphology, differential gene expression and biochemical characteristics. It is emphasized that future research of development biology on sarcosaprophagous insects should fully absorb and integrate the methods of artificial intelligence and omics, and the research object also needs further expansion in order to establish a more objective and more accurate PMI estimation method.

Estimating Postmortem Interval Using Intestinal Microbiota Diversity Based on 16S rRNA High-throughput Sequencing Technology / 法医学杂志

OBJECTIVES@#To explore the correlation between intestinal microbiota and postmortem interval(PMI) in rats by using 16S rRNA high-throughput sequencing technology.@*METHODS@#Rats were killed by anesthesia and placed at 16 ℃, and DNA was extracted in caecum at 14 time points of 0, 1, 2, 3, 5, 7, 9, 12, 15, 18, 21, 24, 27 and 30 d after death. The 16S rRNA high-throughput sequencing technology was used to detect intestinal microbiota in rat cecal contents, and the results were used to analyze the rat intestinal microbiota diversity and differences.@*RESULTS@#The total number of intestinal microbial communities did not change significantly within 30 days after death, but the diversity showed an upward trend. A total of 119 bacterial communities were significantly changed at 13 time points after death. The models for PMI estimation were established by using partial least squares (PLS) regression at all time points, before 9 days and after 12 days, reaching an R2 of 0.795, 0.767 and 0.445, respectively; and the root mean square errors (RMSEs) were 6.57, 1.96 and 5.37 d, respectively.@*CONCLUSIONS@#Using 16S rRNA high-throughput sequencing technology, the composition and structure of intestinal microbiota changed significantly within 30 d after death. In addition, the established PLS regression model suggested that the PMI was highly correlated with intestinal microbiota composition, showing a certain time series change.

Application of Chrysomya rufifacies (Diptera, Calliphoridae) to Postmortem Interval Estimation in Southwest China: A Case Report / 法医学杂志

Insect samples found on human corpses can provide the information important to estimating the minimum postmortem interval (PMImin). A female cadaver, found in a deserted factory in Chongqing of China, was confirmed as a homicide case after the forensic investigation and autopsy. Determining the time of death was difficult due to the inconsistent degree of decomposition in different parts of the decedent. The insect specimens found on the cadaver were identified to be Chrysomya rufifacies (C. rufifacies, Macquart) by morphology and mitochondrial DNA sequence analysis. The PMImin was estimated to be 452 h, based on the developmental rate of C. rufifacies. The PMImin was estimated suc-cessfully to be almost precise, which provided an important entomological evidence for case investiga-tion and suspect prosecution. In so doing, this highlights the usefulness of entomological evidence of specific species in the geographic area for PMI accurate estimation, especially in the case of advanceddecomposed corpses.

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.

Transcriptome Sequencing Analysis of Chrysomyia Megacephala Pupae in Different Growing Periods / 法医学杂志

Objective To study the growth regulation, environmental adaption and epigenetic regulation of Chrysomyia Megacephala pupae, in order to obtain the transcriptome data of Chrysomyia Megacephala in different growing periods, and lay the foundation for forensic application. Methods The Chrysomyia Megacephala was cultivated and after pupation, 3 pupae were collected every 24 h from pupation to emergence, and stored at -80 ℃ for later use. High-throughput sequencing was performed by Illumina Hiseq 4000 and Unigenes were obtained. The Unigenes were compared by comparison tool BLAST from NCBI in databases such as NR, STRING, SWISS-PROT （including Pfam）, GO, COG, KEGG in order to obtain the corresponding annotation information. The expression amount of Unigenes obtained by sequencing in Chrysomyia Megacephala in six different growing periods was calculated by FPKM method, and the discrepant genes were screened according to the following standards： the log2 multiple absolute value of FPKM expression amount between two different growing periods must be larger than 1 （log2|FC|>1）, and the false discovery rate must be less than 0.05. Results When the mean temperature was 25.6 ℃, Chrysomyia Megacephala emerged 6 d after they pupated. A total of 43 408 pieces of Unigenes were obtained and their mean length was 905 bp, of which 32 500, 18 720, 13 542, 9 191 and 18 720 pieces were annotated by NR, SWISS-PORT, Pfam, STRING and KEGG databases. According to the discrepant gene analysis of pupae in two different growing periods, the number of genes with variants ranged from 801 to 5 307, and the total number of discrepant genes was 45 676. Conclusion The gene expressions of the transcriptome data of Chrysomyia Megacephala pupae in different growing periods are different. The results provided a good foundation for further research on the transcriptome changes in each period of the pupae of sarcosaprophagous flies and provided the basis for exploring the genes associated with the growth of Chrysomyia Megacephala pupae.

Progress and Application of Entomological Evidence in Forensic Science / 法医学杂志

Entomological evidence provides entry points and clues for cases detection, in terms of estimation of the postmortem interval （PMI）, and place and cause of death. In recent years, the feasibility of entomological evidence in practice has been proved by theories and cases. It especially plays an important role in the investigation of cases with unnatural death, no monitoring, and highly corrupt cadaver. However, there are still some key issues to be further studied and standardized before the application of entomological evidence to forensic practice, to improve the effect of entomological evidence in forensic investigation and trial. This paper retrospectively reviews key studies of the application of entomological evidence in forensic science, mainly including discussion of forensic entomology inspection standard, identification studies of sarcosaprophagous insect species, collection of sarcosaprophagous insect growth and succession data under different environments and forensic entomotoxicology. With the rapid development of information technology and biotechnology, applying artificial intelligence and whole genome sequencing technology in forensic entomology has become a new research direction, which can improve the application value and range of entomological evidence in forensic science.

Development of Dermestes Maculatus at a Constant Temperature and Its Larval Instar Determination / 法医学杂志

Objective To establish the basic data for estimating minimum postmortem interval （PMImin） of heavily decayed and skeletonized remains by studying the development of Dermestes maculatus DeGeer （Coleoptera: Dermestidae）. Methods The developmental stages of Dermestes maculatus were observed at four constant temperatures of 20 ℃, 24 ℃, 28 ℃ and 32 ℃, and the changes in body length were also examined as the biological indicator to estimate larval day-age and instar. Results The total developmental time from egg to adult at 20 ℃, 24 ℃, 28 ℃ and 32 ℃ were （126.7±10.6） d, （69.4±8.2） d, （50.4±8.4） d and （49.6±6.5） d, respectively. The body length increased gradually, but changed irregularly as a whole. Conclusion The study provides basic data on the development and growth of Dermestes maculatus, especially on its developmental duration as a significant value for estimating PMImin of heavily decayed and skeletonized remains. Nevertheless, the change of body length is not found to be the best biological indicator for instar determination.

Sequential Changes of Total Adenine Nucleotide and Adenylic-Acid Energy Charge in Muscles of Rats after Death / 法医学杂志

Objective To determine the purine adenylate [adenosine triphosphate （ATP）, adenosine diphosphate （ADP）, adenosine monophosphate （AMP）] content in the muscles of both hind limbs of rats at different postmortem interval （PMI）, calculate the changes in the total adenine nucleotide （TAN） content and the adenylic-acid energy charge （AEC）, and explore their relationship with PMI. Methods Healthy rats were sacrificed by cervical dislocation and kept at 20 ℃. The muscles of their hind limbs were extracted at 0, 24, 48, 72, 96, 120, 144, and 168 h after death. Reversed-phase high performance liquid chromatography was used to determine the content of purine adenylates, the TAN and AEC of the muscles of the both hind limbs were calculated, and the related regression equations of their relationship with PMI were established. Results Within 168 h of death of rats, the trend of ATP change was different from ADP, and the content of AMP continuously increased. The TAN value gradually increased with the extension of PMI, and the AEC showed a downward trend within 168 h after death. Among them, the patterns of AEC changes with PMI were obvious, the correlation coefficient was high （ R2=0.903）, and the curve fitting relationship was good; the fitting relationship between ATP, ADP, AMP, TAN and PMI was poor （ R2=0.198-0.754）. Conclusion The postmortem change patterns of AEC provide new research ideas for PMI estimation in the forensic field.