ABSTRACT
Objective: To improve the traditional teaching technique of using probe to destroy the brain tissue and spinal cord of toads. Methods:On the basis of the traditional teaching content, the distance of the probe entering the skull cavity and the specific feeling mark of destroying the brain tissue and spinal cord were added. Students were randomly divided into normal group and improved group according to the class. We observed the success rate and time spent on both the first and the second operations in the two groups. Results: The success rate of destroying the brain tissue and spinal cord in the improved group was high (93.2% vs. 72.3% for the first time). The secondary success rate was 97.7% vs. 85.1%, and it took less time (311.7±89.3) seconds vs. (511.6±171.1) seconds for the initial operation, The secondary operation time was (161.3±63.5) seconds vs. (266.0±98.2) seconds, with significant differences between the two groups (P<0.05).Conclusion: After the improvement of the content of destroying the brain tissue and spinal cord of toads in traditional teaching, it is easy to be mastered by students, with high success rate, less time spent, greater consistency with the 3R principle, and easier to be popularized and applied in teaching.
ABSTRACT
Objective To perform a spatial analysis of myocardium uhrastructure and the activity of mitochondrial succinate dehydrogenase in sub-acute Keshan disease. Methods Myocardium samples were collected from the cases with sub-acute Keshan disease and non-myocarditis(control), and their ultrastructure was observed under electron microscope. The density of mitochondrion volume and cristal membrane and its volume were measured by a point-counting method, while mitochondrion volume was estimated by water displacement method, succinate dehydrogenase activity of mitochondrion by iron-copper method in sub-acute Keshan disease and non-myocarditis cases. Results The volume ratio of mitochondrion to the cell on myoeardium [(47.79±6.20)%], the area ratio of mitochondrion to sarcoplasm [(55.06±6.50) %], mitochondrion to myofibrils [(1.43±0,41)%], mitochondrion section area[(0.78±0.15)μm2], and ratio of the lesion of cristal membrane area to the matrix area and mitochondrion volume[(67.14±13.96)%, (44.62±13.44)%]in sub-acute Keshan disease group were obviously higher than those in control [(33.20±7.62)%, (38.07±9.43)%, (0.71±0.33)%, (0.44±0.07)μm2, (14.11± 12.51)%, (9.34±11.28)%; t = 3.75,7.93,6.61,36.40,52.65,37.51, all P < 0.05]. The volume ratio of myofibrils to cell[(34.52±5.12)%]and the area ratio of cristae mitochondria to matrix[(32.43±14.42)%]in sub-acute Keshan disease group was obviously less than those in control [(48.51±4.30)%, (86.04±12.37)%; t = 9.85, 53.46, both P < 0.05)]. Succinate dehydrogenase activity was negative in sub-acute Keshan disease group. Conclusions Myocardium ultrastructure changes in sub-acute Keshan disease including the increase of volume and areas of mitochondria and the damage of the cristal membrane in mitochondria. Succinate dehydrogenase activity is decreased or even disappeared.