贯通动物解剖与厌氧微生物培养的实验教学改革

以本科动物生物学实验与微生物学实验教学为基础,利用两门课程在课程内容衔接、课时安排和实验材料利用上的连续性和时序性,将两门课程的部分实验内容进行有机整合,形成跨课程的综合性实验教学内容。通过这种整合,可以在以往独立实验操作训练的基础上,进一步系统地训练学生动物形态解剖与分类、无菌操作、厌氧菌培养及动物肠道微生物结构认知等。通过训练学生实验操作与贯穿实验内容,培养学生实验设计能力、实验操作能力、理论知识综合运用能力和创新能力,引导学生设计大学生创新创业项目并组织申请,达到有效提高实验教学效果并激发学生科研兴趣的培养目的。

Postmortem regional distribution of morphine in dependent rats

Objective: Morphine concentration measured in postmortem tissues may or may not reflect antemortem concentration. We measured levels of morphine in autopsied tissues to determine whether morphine distribution in morphine-dependent rats is altered after death. Methods: Solid-phase extraction was used to extract morphine from the samples, and morphine levels were measured at 0-96 h postmortem using gas chromatography. Results: The study of the morphine dependent rats showed a significant (P<0.05) increase of morphine concentration in postmortem cardiac blood, liver tissues and kidneys tissues. A significant increase was also observed at 72 h and 96 h postmortem in the brain, while morphine levels in cardiac tissues only increased at 24 h and 96 h postmortem. These changes were associated with an observed pH rapid decrease: pH of cardiac blood dropped from 7.36±0.15 to 6.86±0.09 (P<0.01), pH of liver tissues from 6.98±0.04 to 6.34±0.03 (P<0.05). Conclusion: The postmortem regional distribution of morphine occurs in dependent rats, but different from the change that occurs in acute poisoning rats. The morphine concentration in cardiac blood and tissues tends to increase during the period of 0-96 h postmortem in dependent rats. Morphine concentration increases with pH rapid decrease. The antemortem internal amount of morphine affects its postmortem regional distribution. It appears that several mechanisms are accountable for postmortem morphine distribution. The understanding of the mechanisms and patterns may eventually lead to better choices of samples which may better represent antemortem drug levels.

Improvement of mount preparations in showing myenteric nerve plexus from intestines of mice

Objective: The whole mount preparations of digestive tract is an effective experimental way to study the appearance and distribution of nerve plexus in digestive tract. Although myentric nerve plexus preparations technique was reported very early. But we have done experiment over and over during our research work in order to improve this traditional method and to meet the needs of our research work, we made some progresses in regular mount preparations after many experiments, which helped offer better situation in observing myentric nerve plexus. Methods: Five healthy male adult Kunming mice (20-30 g in weight) were used in this study. After intraperitoneal injection of muscle relaxant, with dislocation of cervical vertebra method, the abdominal cavity was exposed through abdominal median incision. After several steps of mount preparations the mucous layer and longitudinal muscle layer mount preparations with myentric nerve plexus were stripped under anatomical microscope. Immunohistochemical staining was also used in our study. Results: The mount preparation samples with myentric nerve plexus from intestines of mice showed positive SP immunoreaction. The positive cells were dark brown. Many of the cytons appeared circular and oval, while some appeared triangular or irregular. Conclusion: Our improved method is really a good method to show enteric nerve plexus. The method has many advantages and is particularly applied to small animals such as Kunming mice and BALB/c mice, weighing from 20 g to 30 g.

MORPHOLOGICAL CHANGES OF RATS MUSCLES AT VARIOUS POSTMORTEM INTERVALS BY SCANNING ELECTRON MICROSCOPY

The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the scanning electron microscope(SEM) and the light microscope by phosphotungstic acid haematoxylin(PTAH) stain. The results showed that the striations of muscle were blurred within 4 h, but they became apparent from 6 h to 24 h after death. The authors suggest that this phenomenon be associated with the increased resistance of muscle against the postmortal changes. The observations by scanning electron microscopy and light microscopy have revealed that the muscles do contract in the process of rigor mortis because the distance between two Z lines shortens and the I band narrows, compared with those in anaesthetised animals. The basic biochemical process for the formation of rigor mortis is the same as that of muscle contraction except that the former happens postmortem and the latter antemortem.

Anatomical Study of the Intercostobrachial Nerve in Sprague-Dawlay Rats

OBJECTIVE The aim of the study was to explore the anatomy of the in-tercostobrachial nerve in rats. METHODS Dissections of 8 Sprague-dawley rats were performed to examine the intercostobrachial nerve. Fifteen dissections were successful. The position of the nerve, origin, termination, length and diameter were measured and recorded. RESULTS 1) 80% of the nerves originated from the second intercostal space and 20% from the first intercostal space; 2) 60% of the nerves terminated in the latissimus dorsi and 40% in the axillary skin 3) the branches of the nerves only were divided into 2 types, single and double; 4) the length of the nerves ranged from 2.4 to 3.4 cm with an average of 2.97±0.90 cm; 5) the diameter of the nerves was thicker at their origin compared to their termination. CONCLUSION The intercostobrachial nerve is simple in rats with 60% terminating in the latissimus dorsi.

A new way to produce descending thoracic aorta dissection in the dogs

To oonstruct a canine thoracic aortic dissection （TAD） model for later studying. Methods： we opened the thorax of the dog and exposed the aorta. The descending aorta right below the left innominated artery was damped. The median was cut 1/3 in depth and 1/3 in circumference. Then the head of the ballcon was put into the interspace of the median, the balloon was dilated after putting forward the tube, the normal saline was instilled into the interspace and a suit pressure was kept. The balloon proceeded alongside the separation of the median. After that the elasticity Protease was instilled into the separation maintained for 2 hours. The balloon was put out, the other 2/3 of the median in depth and the intima were cut. The external 1/3 part of the median and the adventitia were sutured. At last the chest wall was dosed. Results： TAD model was established instantly, proved by angiography, MRI and autopsy. Conclusion： it is applicable to construction of a canine TAD model by this procedure.