染料木素对心肌缺血大鼠的血流动力学影响

[目的]研究染料木素对大鼠心肌缺血的保护作用,观察染料木素对心肌缺血大鼠的血流动力学各项参数的影响。[方法]采用结扎左冠状动脉前降支致急性心肌梗死模型,将心肌梗死模型大鼠随机分为：心肌缺血模型组,假手术组,染料木素高、中、低剂量组,丹参对照组,测左心室等容收缩期室内压最大上升速率（＋dp/dtmax）、左心室等容舒张期室内压最大下降速率（-dp/dtmax）;运用N-BT染色法测定各组心肌缺血梗死面积。[结果]染料木素可明显增加心肌缺血大鼠LVSP、±dp/dt max,降低LVEDP,与模型组相比有显著性差异（P〈0.05）;染料木素可以明显减少结扎大鼠冠脉所致大鼠心肌缺血所引起的心肌梗死面积,与模型组相比有显著性差异（P〈0.05）。[结论]染料木素可提高大鼠心肌缺血心室壁顺应性,改善心脏功能,降低心肌缺血心肌梗死面积。     

Systemic arterial hypertension secondary to chronic kidney disease in two captive-born large felids

Systemic arterial hypertension (SHT) has been widely described in the domestic cat (Felis catus). In these feline patients, SHT is considered as the most common vascular disorder of middle-aged to older animals, and secondary SHT related to chronic kidney disease (CKD) represents the most common form of the disease.We describe here the first two cases of spontaneous SHT in large felids, i.e. one 18-year old, 34.4 kg, male North-Chinese leopard (Panthera pardus japonensis, case #1) and one 20-year old, 28.7 kg, female snow leopard (Panthera uncia, case #2), both captive-bred and previously diagnosed with CKD. Both animals underwent complete echocardiographic examination under general anesthesia due to abnormal cardiac auscultation (heart murmur and/or gallop sound), and recurrent lethargy in case #1. The combination of left ventricular remodeling with moderate aortic regurgitation of high velocity was highly suggestive of SHT, which was confirmed by indirect blood pressure measurement (systolic arterial blood pressure of 183 mmHg for case #1 and 180 mmHg for case #2). Amlodipine was prescribed (0.35–0.70 mg/kg/day orally) for 31 and 6 months respectively after the initial diagnosis. In case #1, concurrent amlodipine and benazepril treatment was associated with decreased heart murmur grade and reduced aortic insufficiency severity. These reports illustrate that, similarly to domestic cats, SHT should be suspected in old large felids with CKD and that amlodipine is a well-tolerated antihypertensive drug in these species.     

Functional improvement of infarct heart by implantation of human adipose-derived mesenchymal stem cells delivered by matrigel

AIM: To investigate the implantation of matrigel carrying human adipose-derived mesenchymal stem cells to enhance the cell survival and the improvement of the ventricular functions in infarct heart.METHODS: Human adipose-derived mesenchymal stem cells (ADMSCs) were isolated and cultured from adult adipose tissue. SD rats with one-week-old myocardial infarction were randomly received the following 4 treatments: injection of PBS, matrigel, PBS+ADMSCs or matrigel+ADMSCs, respectively. Labeled ADMSCs either in matrigel or in saline were injected into the border area of ischemia. The controls received the injection of matrigel or saline only. Four weeks after injection, the heart functions were determined by echocardiography. The densities of the micro-vessels within the infarct area were also measured.RESULTS: Four weeks after implantation of ADMSCs, the cell graft size, the heart functions and the micro-vessel densities within the infarct area improved in matrigel+ADMSCs group as compared to other groups.CONCLUSION: The co-injection of ADMSCs with matrigel enhances the graft survival, increases the density of the micro-vessels in the myocardium and improves the cardiac functions.     

Biological characteristics of primarily cultured microvascular endothelial cells in mouse myocardium

AIM：To investigate an effective and stable method to isolate myocardial microvascular endothelial cells (MMVECs) from the mouse heart and to observe their biological characteristics.METHODS：The cells from the mouse heart were isolated by collagenase II digestion followed by different speed adhesion. Then the cells were cultured on the dish coated with polylysine in endothelial cell-specific culture medium. The biological characteristics were observed by trypan blue staining. The cell growth curve and the cell proliferation were also evaluated by MTT assay at different passages. The expression of DiI-ac-LDL, FITC-UEA-1, specific markers of endothelial cells and the expression of CD31, vWF and CD34 were determined by immunofluoresence staining. To evaluate the function of the MMVECs, in vitro tube formation was evaluated under microscope.RESULTS：Two days after the enzyme digestion, the MMVECs formed small and isolated clusters. The MMVECs grew quickly in monolayer with the characteristics of endothelial cell shape at 4~5 d. The cells became confluent and cobblestone-like which were ready for passage at 7~8 d. After passage, the viability of the cells was more than 95%. The first and the third generation of the cells presented an S-shape growth curve. The cell proliferation of the first to the third generation was quick and slowed down after the fifth passage. MMVECs were highly positive for DiI-ac-LDL and FITC-UEA-1 ［(89.2±3.5)%］, indicating the cells were MMVECs. The other relative antigen expression (CD31, vWF and CD34) on the MMVECs was (56.7±3.7)%, (78.5±2.6)% and (67.8±4.2)%, respectively. The MMVECs formed the tubes in vitro after cultured for 6～12 h.CONCLUSION：We can obtain high-purity MMVECs using the combination of collagenase II digestion, the different speed adhesion process and the endothelial cell-specific culture medium for effective and reliable MMVECs isolation and culture.     

Effects of apelin-13 on transient sodium currents in rat ischemic ventricular myocardial cells

AIM：To investigate the effects of apelin on ventricular arrythmias and cardiac functions in rat Langendorff perfusion-simulated myocardial ischemia model by observing the changes of transient sodium currents (INa) in normal cells and the simulated ischemic cells in rat left ventricle. METHODS：Ventricular cells were enzymatically isolated by the Langendorff perfusion system. INa was recorded by the technique of whole-cell patch-clamp. Some elements in the extracellular fluid were changed to simulate the normal or ischemic status. Forty Wistar rats were divided into 4 groups：normal group, ischemic group, normal with apelin group and ischemic with apelin group. The effect of apelin-13 on INa was observed. The method of rat Langendorff perfusion was used to simulate the ischemic heart model. The ventricular arrhythmia scores and heart functional parameters were compared. The expression level of sodium channel protein,type V,alpha subunit (SCN5A) in ventricular ischemic cells was measured by Western blotting. RESULTS： Apelin-13 increased INa amplitude in both normal myocardial cells ［(-86±13） pA/pF］ and ischemic myocardial cells ［(-52±15） pA/pF］. The results of current-voltage curve analysis indicated that apelin-13 did not change the conduction velocity of INa in the 4 groups ［(3.2±0.2） pS/pF, （3.1±0.3） pS/pF,（2.9±0.1）pS/pF and （2.8±0.4） pS/pF,respectively, P>0.05］. The membrane potentials at 50% maximal activation in the 4 groups were （-21.9±0.6） mV, （-28.7±0.3） mV, （-30.5±0.7） mV and （-36.8±0.2） mV, respectively, and the slope of activation curves was 5.6±0.3, 5.1±0.4, 4.3±0.3 and 4.9±0.6 (P>0.05), respectively. No difference of ventricular arrhythmia scores between normal group and normal with apelin group, as well as between ischemic group and ischemic with apelin group was observed. LVEDP in normal with apelin group was lower than that in normal group.The dp/dtmax and dp/dtmin in normal with apelin group were higher than those in normal group. Apelin improved cardiac function parameters in the ischemic hearts. The expression of SCN5A was not affected by apelin (28.8±3.6, 29.4±4.1, 30.1±2.9 and 31.3±3.8,respectively,P>0.05). CONCLUSION：Apelin-13 changes the gating properties of sodium channel, enhances the peak INa and facilitates the opening of sodium channel without inducing ventricular arrhythmias. Apelin-13 has a positive inotropic effect on both normal and ischemic hearts.     

奶牛氧化应激研究进展

高产奶牛更容易发生氧化应激,氧化应激可以导致生物学大分子和生物膜系统的破坏,并可以增加炎症反应时的组织损伤：奶牛氧化应激的产生除了与机体的生理状态、健康状况和饲料成分有关外,环境因素也会引起氧化应激。目前主要通过饲喂抗氧化添加剂来预防奶牛氧化应激。     

冷温血停搏液联合灌注对犬心肌超微结构的影响

为客观地比较血停搏液不同灌注对心肌保护作用,２８只低温体外循环犬,按停搏液灌注方式随机分为４组：Ａ组为冷晶组,Ｂ组为冷血组,Ｃ组为温血组,Ｄ组为冷温血组。采用电子透射显微镜观察实验犬心肌缺血再灌注期心肌细胞的超微结构变化。结果显示,冷温血停搏液联合灌注组在心肌缺血期,再灌注６０ｍｉｎ两时点,与冷晶组,冷血组和温血组各对应点相比,心肌细胞的线粒体损伤最轻,心肌破坏较小。     

营养素对心肌肥厚影响的研究进展

心肌肥厚(Myocardial hypertrophy,MH)是一种以心室壁增厚为主要特征,长期可诱发心脏收缩和舒张功能不全,最终导致心肌衰竭、心律失常、心肌缺血甚至猝死的功能性改变并发症。研究发现,心血管疾病的病因,与遗传、环境和生活方式等因素有关,合理的膳食营养素摄入可以影响心脏的代谢水平,改善心血管功能,降低心肌肥厚发病的风险。通过调整饮食结构来预防和缓解心肌肥厚无疑提供了一种全新的治疗新思路。论文综述近年来蛋白质、糖类、脂肪等宏量营养素及维生素、矿物质等微量营养素对心肌肥厚发病的影响,并从膳食营养素的角度探索预防和治疗心肌肥厚的策略。     

小麦条锈病防治指标的初步研究

通过对不同小麦品种的产量损失预测,根据损失的程度,将感病品种分为比较耐病品种、一般感病品种及特别敏感型品种。研制了用普遍率转换病情指数的Inc-Ind模型,认为二者的关系用Weibull模型拟合较好。研究结果表明,病害防治指标的确定,以小麦扬花期普遍率低于30％、旗叶始见期在4％时较为适宜。并且根据田间实查的病情推算出病害防治指标的方法,编排了实用的计算机程序。