Melatonin‐evoked potentiation of the juvenile rat tail artery neurogenic reactivity depends on degree of the change in the reactivity

Aim: Dependence of the melatonin‐evoked potentiation of the rat tail artery neurogenic reactivity on degree of the change in the reactivity was studied. Method: Electrical field stimulation‐evoked contractile response of the juvenile rat tail artery segment under isometric conditions was recorded. 0.1 μm melatonin was administered after the change in the response produced both spontaneously and by acidification (pH 6.6) or alkalinization (pH 7.8) of the solution. Results: During the course of experiment, the contraction force continuously declined, being reduced by 12 ± 5, 24 ± 7 and 32 ± 6% at 20, 70, and 170 min after beginning of experiment, respectively. Melatonin applied at these time points increased the contraction by 20 ± 5, 41 ± 10, and 48 ± 8%, respectively, relative to control. This increase in potentiating effect of melatonin during the course of experiment was not because of sensitization of the segment to the hormone. Acidosis‐induced considerable decline in neurogenic contraction was counteracted by melatonin, while after alkalosis‐induced augmentation in the contraction the hormone was not effective. Melatonin increased the artery response to 0.1 μm noradrenaline. Conclusion: These data suggest that melatonin can restore an attenuated neurogenic reactivity of the juvenile rat tail artery. The effect is more pronounced with further decrease in reactivity and might be due to a change in sensitivity of the post‐junctional membrane to noradrenaline.     

大鼠肝移植的麻醉

目的研究氯胺酮在大鼠肝移植中的合适剂量.方法对100只雄性Wister大鼠行40例肝移植,观察供受体麻醉过程、药物剂量和效果. 结果供体手术氯胺酮麻醉的剂量以100～125 mg/kg合适,受体手术氯胺酮麻醉的剂量以75～100 mg/kg合适.结论在大鼠肝移植的手术中,氯胺酮是一种理想的麻醉药品.     

酸性成纤维细胞生长因子促血管内皮细胞增殖作用的实验研究

目的　探讨不同浓度的aFGF对体外培养的大鼠主动脉内皮细胞生长的影响。方法　通过组织块培养法获取主动脉内皮细胞。将浓度为 5ng/ml,10ng/ml,2 0ng/ml的aFGF分别加入内皮细胞的培养液中作为实验组(Ⅰ～Ⅲ组 ) ,不加aFGF的组作为对照组。分别在 2 4h、48h和 72h应用MTT法进行细胞计数。结果　从大鼠主动脉成功地获取了内皮细胞。 3天内 ,实验组和对照组的主动脉内皮细胞都有不同程度的增殖 :培养 2 4h ,实验各组与对照组比较P >0 .0 5 ,无统计学差异 ;48h和 72h时 ,Ⅱ、Ⅲ组与对照组以及与Ⅰ组两两比较 ,有非常显著的差异 (P <0 .0 0 1) ;各时间段内 ,Ⅰ组与对照组 ,Ⅲ组与Ⅱ组比较 ,细胞数改变未见差异 (P >0 .0 5 )。结论　一定浓度的aFGF有非常明显的促血管内皮细胞生长的作用 ,可能对缺血性心脏病的促血管形成治疗有较大的帮助。     

柔肝消瘢饮对肝硬化大鼠血清和肝组织IL-1β和IL-6含量的影响

目的：观察柔肝消瘕饮对肝硬化大鼠肝组织病理形态学和血清、肝组织IL-1β、IL-6含量的影响。方法：采用复合因素造模法复制肝硬化大鼠模型，以复方鳖甲软肝片为对照，观察柔肝消瘢饮对肝硬化大鼠肝组织病理形态学、血清和肝组织IL-1β、IL-6含量的影响。结果：与正常组比较，模型组大鼠出现肝小叶损害，纤维组织增生，假小叶形成，血清IL-1β、IL-6含量和肝组织IL-6含量均明显升高（P〈0．01或P〈0．05）；与模型组比较，各治疗组肝组织病理损害减轻，血清IL-1β和肝组织IL-6含量均有明显下降，差异有显著性意义（P〈0．01或P〈0．05）；与对照组比较，高剂量组血清IL-6含量明显降低（P〈0．05）。结论：柔肝消瘢饮能显著下调肝硬化大鼠血清IL-1β、IL-6含量和肝组织IL-6含量，具有减轻肝硬化炎症损害，改善肝组织病理形态学作用。     

大鼠移植胰腺冷缺血再灌注后细胞凋亡的变化

目的　探讨移植胰腺冷缺血再灌注后胰腺细胞凋亡的变化过程。方法　 6 5只SD大鼠随机分成 7组 :假手术组 ,冷缺血 2h组 ,冷缺血 2h再灌注 1、3、6、9、12h组。通过HE染色后光镜及电镜观察各组的胰腺组织的病理变化 ;采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(TUNEL)检测凋亡细胞的分布及计数。结果　胰腺移植后早期即可观察到细胞凋亡的典型改变 ,胰腺冷缺血再灌注后发生凋亡的高峰期为再灌注后 3h[AI为 (9.4 6± 2 .91) % ,P <0 .0 1) ,再灌注 6h较 3小时细胞凋亡有所减少 [AI为 (5 .74± 1.6 6 ) % ,P <0 .0 1],再灌注 9h及 12h细胞凋亡进一步减少 [AI分别为 (3.6 0± 1.6 4 ) %及 (3.2 6± 1.35 ) % ,P <0 .0 5 ]。结论　细胞凋亡是胰腺移植后的早期事件 ,移植胰腺冷缺血再灌注后早期主要的死亡方式是凋亡 ;移植胰腺冷缺血再灌注后的凋亡高峰发生在再灌注后 3h。     

Pharmacological studies on siculine syrup. II: effects on smooth,skeletal and cardiovascular muscle preparations

Earlier pharmacological screening showed that siculine syrup (a traditional herbal remedy purported to be useful in the prevention and treatment of sickle cell pain – crises, due to sickle cell anaemia – SCA) had antisickling and analgesic activities as well as antimicrobial and diuretic effects. SCA is an important haemoglobinopathy in Africa and many other communities/countries worldwide, with relatively high morbidity and mortality. The present study was to determine the effects of the extract on various isolated muscle preparations – smooth, skeletal and cardiovascular. Siculine (4–20 µg/mL), like acetylcholine (40–400 µg/mL), contracted the isolated rat uterus concentration dependently. Similar effects were observed with the guinea‐pig ileum and rabbit jejunum (2–20 µg/mL). In contrast to these effects, the direct (muscle) and indirect (nerve) stimulations of rat phrenic nerve–diaphragm were relaxed by siculine (4 and 8 µg/mL) and d ‐tubocurarine (0.8 µg/mL). Siculine also concentration‐dependently decreased both the rate and force of contraction of guinea‐pig atria and rabbit heart and also resulted in a fall in cat blood pressure in a manner similar to those of acetylcholine. The possible therapeutic and/or toxicological consequences of these effects including the hypotensive activity is noteworthy since siculine syrup is used by the local population for the prevention and treatment of sickle cell pain crises. Copyright © 2008 John Wiley & Sons, Ltd.     

大鼠胰腺十二指肠移植的手术技巧

目的探讨建立大鼠胰腺十二指肠移植模型的手术技巧。方法不阻断体循环，采用双套管将供胰所带腹主动脉、门静脉分别与受鼠的左肾动、静脉进行套管吻合，尽量减轻对全身血流动力学的影响；同时行十二指肠空肠端侧吻合引流胰液，重建胰腺外分泌途径；围手术期注意补液、保暖及抗凝。结果100例手术中83例手术成功，术后移植胰腺具有内分泌功能，胰腺轻度充血水肿。结论该移植模型不阻断体循环且操作简单实用，其成功的关键在于手术操作及围手术期处理。     

自发性高血压大鼠颈动脉血管平滑肌中抑癌基因P53和原癌基因c-jun、c-fos、c-myc mRNA表达的研究

目的探讨自发性高血压大鼠颈动脉中抑癌基因P53和原癌基因c-jun、c-fos、c-myc mRNA的表达.方法用逆转录聚合酶链式反应检测两种基因的表达水平.正常雄性大鼠作为对照组.结果 SHR颈动脉中,抑癌基因P53和原癌基因c-jun、c-fos、c-myc均有高表达,较WKY差异有显著性(P<0.05).结论自发性高血压大鼠颈动脉组织中抑癌基因P53和原癌基因c-jun、c-fos、c-myc均有高表达,癌基因的活化可能与自发性高血压大鼠颈动脉血管重构有关.     

Plasma volume in fasted pregnant rats

The effect of a two day fast on maternal plasma volume and plasma protein concentration was explored in pregnant rats. Fasting between days 17 and 19 of gestation prevented the rise in plasma volume observed in ad libitum fed rats. Plasma protein concentration declined between day 17 and day 19 in both fasted and not fasted rats. Placental weight was not reduced by fasting during this stage of gestation. Fetal weight in the fasted group was 91% of the fetal weight of the ad libitum fed group. These results show that acute undernutrition, like longer term food or protein restriction, can prevent adequate plasma volume expansion and slow fetal growth.     

Orthotopic placement of the dunning R3327 AT-3 prostate tumor in the copenhagen X fischer rat

Orthotopic placement of in vitro propagated Dunning R3327 AT-3 tumor cells resulted in a greater percentage of tumor takes and a two-fold shift in the exponential growth curve compared to flank implantation. The orthotopic tumor appeared to disseminate preferentially to regional lymph nodes, rather than to the lungs which is characteristic of flank tumors. The results suggest an important role of stromal-epithelial interactions in the growth of this tumor. © 1995 Wiley-Liss, Inc.