The changes of Fourier transform infrared spectroscopy in rat's brain / 法医学杂志

OBJECTIVE@#To apply Fourier transform infrared (FTIR) spectroscopy to study the process of postmortem degradation of the rat brain and to provide a new way for the estimation of postmortem interval (PMI).@*METHODS@#The rats were sacrificed by cervical dislocation and the bodies were kept in a controlled environmental chamber set at (30 +/- 2) degrees C. To measure the content of the chemical groups in postmortem rat brains at the different time points from 0 to 36 h using the FTIR spectrograph.@*RESULTS@#With prolongation of PMI, the peak position of main absorbance bands in the FTIR spectra showed no significant changes, while the peak levels showed dramatic changes: (1) The relative peak intensity of 1080 cm(-1), 1238 cm(-1) (I1080/I1398, I1238/I1398) associated with nucleic acid decreased obviously; (2) The peak intensity ratio at Amide I, II (I1647/I1541) decreased; (3) The peak intensities at 1456 cm(-1) and 1398 cm(-1) showed a decreased and an increased trend, respectively; (4) Compared to the peak intensity of 1647 cm(-1), the peak intensities at 2852 cm(-1), 2871 cm(-1), 2923 cm(-1), and 2958 cm(-1) tended to increase, with only a slightly increased tendency in peak intensity of 2871 cm(-1).@*CONCLUSION@#FTIR spectroscopy may be potentially used as an effective method for estimating the PMI in medicolegal practice using brain tissue sample.

Expression of brain natriuretic peptide and c-fos gene in rat after acute myocardial ischemia and its medicolegal significance / 法医学杂志

OBJECTIVE@#To study the mRNA expression of BNP and c-fos gene in rat heart after acute myocardial ischemia (AMI) and to provide a marker for its medicolegal diagnosis.@*METHODS@#AMI animal model of rat was made by ligating LAD. mRNA expression of BNP and c-fos gene were studied with RT-qPCR and ordinary PCR at 10 min, 30 min, 60 min and 3h after the successful ligation. The H&E staining was also used. Changes of the mRNA expression in different time groups were compared.@*RESULTS@#There was significant difference in BNP mRNA expression of the 3 h group by RT-qPCR compared with normal control group, 10 min, 30 min, and 60 min groups (P < 0.05). There were dramatic differences in c-fos mRNA expression between every two groups (P < 0.05) except between the normal group and the 10 min group, between the 30 min group and the 3 h group. The peak of c-fos expression was in 60 min group. No difference was shown between groups by the ordinary PCR. Myocardial fiber acidophilia staining and wavy changes could be seen occasionally at 3 h experimental group by H&E staining.@*CONCLUSIONS@#C-fos gene probably be used as an auxiliary test for myocardial ischemia of duration of 30 minutes or longer. RT-qPCR may be suitable for diagnosis of early AMI.

Morphological changes in rabbits died of potassium intoxication / 法医学杂志

OBJECTIVE@#Morphologic features of the corpse of rabbits died of potassium intoxication were studied in order to elucidate an objective evidence for forensic determination of death caused by potassium intoxication.@*METHODS@#Macroscopic, microscopic, and ultrastructural (by transmission electron microscopy) changes were observed in the heart, brain, and kidney of rabbits killed by intravenous push or continuous infusion at 100 drips per minute with 0.3% and 1% KCl, respectively. Normal rabbits without any treatment killed by bleeding were used as controls.@*RESULTS@#Macroscopically, cardiac dilatation and congestion/stasis as well as ischemic and hypoxic changes in various organs were observed in rabbits died of potassium injection. Microscopically and ultrastructurally, there were destruction of the cardiac fibers with thickening, concentrating, or disappearing of the Z-line, constriction of the glomerular capillaries, enlargement of the Bowman capsule, thinning and fusion of foot processes, as well as apoptosis with phagocytosis in brain observed, particularly in the group infused with 1% KCl.@*CONCLUSION@#The morphologic changes observed in the heart and kidney appear to be characteristic, supporting death caused by potassium intoxication.

Accuracy of age estimation in 14-year-old females by two skeletal age standards / 法医学杂志

OBJECTIVE@#To study the accurate of Li Guozhen's Percent Numeration and the Development Standard of Chinese Wrist Bone CHN Numeration of age estimation in 14-year-old females.@*METHODS@#Fifty-one 14-year-old females from three middle schools in Loudi City in Hunan were selected randomly, whose left wrists were photographed with X-rays under the same condition. Skeletal age was estimated following the two numerations. The two skeletal ages were compared with each other and with chronological age.@*RESULTS@#The skeletal age from Percent Numeration and CHN Numeration have no significance difference, P > 0.05. And the skeletal ages of the two Numerations have no significance difference either, P > 0.05.@*CONCLUSION@#The Percent Numeration and the CHN Numeration are still suited for age estimation in 14-year-old females.