Research Progress on Molecular Changes in Pulmonary Hypoxia and Cause of Death Identification in Mechanical Asphyxia / 法医学杂志

Lung is the largest organ of the respiratory system. During hypoxia, pulmonary cells undergo rapid damage changes and activate the self-rescue pathways, thus leading to complex biomacromolecule modification. Death from mechanical asphyxia refers to death due to acute respiratory disorder caused by mechanical violence. Because of the absence of characteristic signs in corpse, the accurate identification of mechanical asphyxia has always been the difficulty in forensic pathology. This paper reviews the biomacromolecule changes under the pulmonary hypoxia condition and discusses the possibility of application of these changes to accurate identification of death from mechanical asphyxia, aiming to provide new ideas for related research.

Analysis of spectrum-activity relationship among antioxidant parts of Lycii Fructus using three different chemometrics methods / 中国中药杂志

The chemical components of Lycii Fructus were analyzed by liquid chromatography( LC) and mass spectrometry( MS for the establishment of spectrum-activity relationship,on the basis of which its antioxidant active ingredients were determined. In this experiment,Lycii Fructus was extracted with different solvents and then separated into 80 samples by macroporous adsorption resin and reversed-phase chromatography,respectively. The antioxidant components were enriched into 11 samples and their scavenging abilities against DPPH free radical and ferric ion reducing antioxidant power( FRAP) were significantly stronger than those before the treatment( P<0. 05). The spectrum-activity relationship regarding the antioxidant activity in vitro of Lycii Fructus was established by Pearson correlation analysis,orthogonal partial least squares( OPLS) and elastic net regression. Six chromatographic peaks greatly contributing to the antioxidant activity in vitro of Lycii Fructus were identified as rutin( P6),quercetin( P35),scopoletin( P14),N-cis-feruloyl-4-O-β-D-glucopyranosyl-tyramine or N-( 4-O-β-D-glucopyranosyl-trans-feruloyl)-tyramine( P8), ferulic acid( P13) and1,3,5-dihydroxy-2-isoprenyl-3-xanthone( P23). The active components associated with free radical scavenging were rutin and quercetin both belonging to flavonoids. The reduction of Fe3+was based on phenylpropanoids such as ferulic acid,scopoletin,xanthone and phenolic amides. These results indicated that the antioxidant activity of Lycii Fructus was ascribed to the synergistic action of different products through different ways. Besides,the data analysis model should be chosen carefully for the establishment of spectrum-activity relationship,thus ensuring the reliability of results.

Significance of Hypoxia-related microRNA for Estimating the Cause of Mechanical Asphyxia Death / 法医学杂志

Under hypoxia condition, microRNA （miRNA） can interact with transcription factors for regulating the cell metabolism, angiogenesis, erythropoiesis, cellular proliferation, differentiation and apoptosis. The biological processes above may play an important role in mechanical asphyxia death. This article reviews the regulating function of miRNA under hypoxia condition and the influence of hypoxia to biosynthesis of miRNA, which may provide some new ideas to the research of miRNA on determining the cause of mechanical asphyxia death in the field of forensic medicine.

Research Progress on Estimation of Early Postmortem Interval / 法医学杂志

Estimation of postmortem interval （PMI） is very important for judging the nature of cases, restricting the scope of investigation and suspect, which is always the emphasis and difficulty for forensic pathology. Early postmortem interval is the time between 0 and 24 hours after death. Due to the shorter time after the case occurred, precisely estimating early postmortem interval can help solve crimes, which has important significance in forensic medicine. In recent years, series of advanced methods and technologies are used to estimate the early PMI by the internal and overseas scholars who work in the forensic area. This paper reviews the research progress on fluids biochemistry, supravital reactions, metabolomics, imageology and the degradation rule of genetic material to provide a new idea to the study and application for estimation of early PMI.

Correlation between RNA Degradation Patterns of Rat's Brain and Early PMI at Different Temperatures / 法医学杂志

OBJECTIVES@#To explore the correlation between early postmortem interval （PMI） and eight RNA markers of rat's brain at different temperatures.@*METHODS@#Total 222 SD rats were randomly divided into control group （PMI=0 h） and four experimental groups. And the rats in the experimental groups were sacrificed by cervical dislocation and respectively kept at 5 ℃, 15 ℃, 25 ℃ and 35 ℃ in a controlled environment chamber. The RNA was extracted from brain tissues, which was taken at 9 time points from 1 h to 24 h postmortem. The expression levels of eight markers, β-actin, GAPDH, RPS29, 18S rRNA, 5S rRNA, U6 snRNA, miRNA-9 and miRNA-125b, were detected using real-time fluorescent quantitative PCR, respectively. Proper internal reference was selected by geNorm software. Regression analysis of normalized RNA markers was performed by SPSS software. Mathematical model for PMI estimation was established using R software. Another 6 SD rats with known PMI were used to verify the mathematical model.@*RESULTS@#5S rRNA, miR-9 and miR-125b were suitable as internal reference markers for their stable expression. Both β-actin and GAPDH had well time-dependent degradation patterns and degraded continually with prolongation of PMI in 24 h postmortem. The mathematical model of the variation of ΔCt values with PMI and temperature was set up by R software and the model could be used for PMI estimation. The average error rates of model validation using β-actin and GAPDH were 14.1% and 22.2%, respectively.@*CONCLUSIONS@#The expression levels of β-actin and GAPDH are well correlated with PMI and environmental temperature. The mathematical model established in present study can provide references for estimating early PMI under various temperature conditions.

Correlation between five RNA markers of rat's skin and PMI at different temperatures / 法医学杂志

OBJECTIVE@#To explore the correlation between postmortem interval (PMI) and five RNA markers of rat's skin--β-actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 18S ribosomal RNA(18S rRNA), 5S ribosomal RNA (5S rRNA), and microRNA-203 (miR-203), at different temperatures.@*METHODS@#Eighteen SD rats were randomly divided into three environmental temperature groups: 4 °C, 15 °C and 35 °C, respectively. Skin samples were taken at 11 time points from 0 h to 120 h post-mortem. The total RNA was extracted from the skin samples and the five RNA levels were detected by real-time fluorescent quantitative PCR. Proper internal reference was selected by geNorm software. Regression analysis of the RNA markers was conducted by GraphPad software.@*RESULTS@#5S rRNA and miR-203 were most suitable internal references. A good linear relationship between PMI and RNA levels (β-actin and GAPDH) was observed in two groups (4 °C and 15 °C), whereas the S type curve relationship between the expression levels of the two markers (β-actin and GAPDH) and PMI was observed in the 35 °C group. The partial linear relationship between 18S rRNA and PMI was observed in the groups (15 °C and 35 °C).@*CONCLUSION@#Skin could be a suitable material for extracting RNA. The RNA expression levels of β-actin and GAPDH correlate well with PMI, and these RNA markers of skin tissue could be additional indice for the estimation of PMI.