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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.
Asunto(s)
Humanos , Cambios Post Mortem , Autopsia/métodos , ADN/genética , Medicina Legal , Patologia ForenseRESUMEN
Objective: To investigate the modification of live cell membranes with cholesterol linked deoxyribonucleic acid (cholesterol-DNA). Methods: The suspension L1210 cells and adherent PC-12 cells were included. L1210 cells and PC-12 cells were divided into the experimental group (incubated with cholesterol-DNA) and the control group (treated with phosphate buffer saline), respectively. The fluorescence intensity of the cells in the two groups was obtained and the experimental group cells were three-dimensional reconstructed by confocal microscopy. The morphology of the cells in the experimental group was observed by scanning electron microscopy (SEM). The effect of cholesterol-DNA modification on cell membrane fluidity was detected by fluorescence recovery after photobleaching. Results: The results of suspension cells and adherent cells were consistent. Compared with the control group, the fluorescence intensity of cell surface in the experimental group was increased (both P=0.000). Three-dimensional reconstruction of confocal microscopy showed that the fluorescence of the cells in the experimental group was distributed across the surface of the global cell. SEM showed that the morphology of the cells in the experimental group did not change with cholesterol-DNA modification. After fluorescence photobleaching, the relative fluorescence intensity of the L1210 cells in the experimental group was decreased to 0.090, and then recovered to 0.860 within 110 s. Conclusion: Cholesterol-DNA can modify the whole live cell membranes, and the modified cell membranes still have fluidity. This method can modify not only the suspension cells, but also the adherent cells.
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[Objective] To explore the clinical significance of quantitative detection of hepatitis B patients with chronic hepatitis B virus DNA(HBV DNA). [Method] To select 107 cases of chronic hepatitis B patients as the research object in May 2010~March 2013 in our hospital, respectively by using fluores-cence quantitative polymerase chain reaction(FQ-PCR), enzyme-linked immunosorbent assay(ELISA) and rate method to determine the HBV DNA,the hepatitis B virus e antigen(HBeAg) and alanine aminotransferase(ALT) of al the research object. [Results] (1)To compare with mild, moderate and severe chronic hepatitis B patients with HBV DNA level, there was no statistical significance in the difference.(2)Patients with chronic hepatitis B had no correlation between HBV DNA levels and ALT levels. (3) HBeAg positive group of patients with HBV DNA level was significantly higher than that of HBeAg negative patients;to compare the two groups, there was statistical y significant difference. [Conclusion] The severity of patients with chronic hepatitis B and liver celldamage degree have no obvious relationship with HBV DNA level, but the existence of HBeAg and HBV DNA in serum levels have a close relationship, and in the process of clinical diagnosis and treatment of chronic hepatitis B patients, we should consider several factors.
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Objective To investigate the effect of daphnetin on superoxide dismutase (SOD) activity and DNA synthesis in P. falciparum in vitro. Methods The effect of daphnetin, daphnetin-Fe complex and desferrioxamine B on SOD activity of P. falciparum (P. f) FOCI in vitro was determined with a SOD test-kit. The level of DNA synthesis of P. f synchronized cultured in vitro at various developmental stages after treatment of daphnetin or desferrioxamine B was assayed by fluorescein Hoechest 33258. Results The total SOD activity decreased by 60% after daphnetin treatment while it only decreased by 22% if treated with desferrioxamine B. No effect on SOD activity of P. f treated with daphnetin-Fe complex was observed. The level of DNA synthesis of P. f trophozoites in synchronized in vitro culture was significantly lower than that of the control. Conclusion Daphnetin lowered SOD activity and decreased DNA synthesis of P. f in vitro.
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Objective:To provide evidence instruction for breast-feeding,the investigation of positive rates with serum hepatitis B virus markers(HBVM) in infants of breast-feeding to HBVM positive mothers.Methods:The serum HBVM of pregnant women and their infants were determined by ELISA and HBV-DNA in positive serum and colostrum were determined by fluorescence quantitative PCR.The relation between HBVM in the infant serum and the feeding way was analysed.Results:In 67 parturients with serum HBVM antigen positive,the positive rates of HBV-DNA were 84%,26% and 27%,0% in serum and colostrum with HBeAg positive and HBeAg negative mothers;and there was a positive relationship between the serum and colostrum.The positive rates of HBeAg of mothers were 41% and 13% in the artificial feeding group and breast feeding group,there was significant difference between them( P 0.05).Conclusion:The breast-feeding were safe to HBVM positive mothers by active and passive immunization with pregnant women and their infants.