The current situation and development tendency of medical functional virtual experiments teaching / 中华医学教育探索杂志

Virtual experiments teaching has been characterized by openness, interactivity and re-source sharing. It efficiently improves the experiments teaching effects and promotes the teaching reform. At present the virtual experiment systems used by domestic universities can realize simulation of the ex-perimental principle, apparatus, object, operation and data. In the virtual experiment system students deepen the understanding of the experiments through foregrounding and the networked virtual experiment manage-ment effectively improves the effects of experiments teaching through behind-the-scenes action.

Melatonin Attenuates Noise Stress-induced Gastrointestinal Motility Disorder and Gastric Stress Ulcer: Role of Gastrointestinal Hormones and Oxidative Stress in Rats

BACKGROUND/AIMS: There are increasing evidences for gastrointestinal motility disorder (GIMD) and gastric stress ulcer induced by noise stress. The present study was to investigate the reversed effect of melatonin on GIMD and gastric stress ulcer induced by noise stress and potential mechanism. METHODS: Noise stress was induced on rats, and melatonin (15 mg/kg) was administered to rats by intraperitoneal injection. Differences were assessed in gastric residual rate (GRR), small intestine propulsion rate (SPR), Guth injury score, cortisol, gastrointestinal hormones (calcitonin-gene-related peptide and motilin) and oxidative stress markers (superoxide dismutase and malondialde hyde) in blood plasma as well as gastric mucosa homogenate with or without melatonin. The pathological examination of gastric mucosa was also performed. RESULTS: The GRR and SPR were improved by noise stress compared with control (P < 0.05). The pathological examination and Guth injury score revealed gastric stress ulcer. Moreover, the levels of cortisol, motilin and malondialdehyde in blood plasma and malondialdehyde in gastric mucosa homogenate were increased by noise stress (P < 0.05). CGRP and superoxide dismutase activity in both of blood plasma and gastric mucosa homogenate were significantly decreased (P< 0.05). Furthermore, melatonin reversed changes in GRR, SPR, pathological examination, Guth injury score, cortisol, motilin, CGRP, superoxide dismutase activity and malondialdehyde (P < 0.05). CONCLUSIONS: Melatonin is effective in reversing the GIMD and gastric stress ulcer induced by noise stress. The underlying mechanism may be involved in oxidative stress and gastrointestinal hormones.

Homologous amelogenin gene test of archaeological samples / 法医学杂志

OBJECTIVE@#Based on the sequence differences of Amelogenin homologous gene in the X and Y chromosomes, a pair of specific primers was designed to identify the sex of archaeological samples.@*METHODS@#Ancient DNA fragments were extracted from the bones and teeth of sacrificial slaves with an improved method that combines phenol-chloroform extraction, silicon dioxide adsorption with ultrafiltration concentration. The polyacrylamide gel electrophoresis (PAGE) was used to detect PCR products.@*RESULTS@#Seven in sixteen samples from eight graves showed positive results and the targeted segments were visible: a male with two bands of 106bp (Amel-X) and 112 bp (Amel-Y), while a female with only one band of 106 bp (Amel-X). Ancient DNA analyzing results from tooth samples are more marked than that from bones.@*CONCLUSION@#The improved extraction method is more effective for ancient DNA extraction, which reduced the PCR inhibitors and lowered experimental costs. The sex determination technology based on Amelogenin homologous gene is an important and feasible method in the molecular archaeological research.