RADIOGRAPHIC AND ECHOCARDIOGRAPHIC ASSESSMENT OF LEFT ATRIAL SIZE IN 100 CATS WITH ACUTE LEFT‐SIDED CONGESTIVE HEART FAILURE

The aims of this study were to evaluate left atrial size in cats with acute left‐sided congestive heart failure. We hypothesized that left atrial size as determined by thoracic radiography can be normal in cats with acute left‐sided congestive heart failure. One hundred cats with acute left‐sided congestive heart failure in which thoracic radiography and echocardiography were performed within 12 h were identified. Left atrial size was evaluated using right lateral and ventrodorsal radiographs. Measurements were compared to two‐dimensional echocardiographic variables of left atrial size and left ventricular size. On echocardiography, left atrial enlargement was observed in 96% cats (subjective assessment) whereas maximum left atrial dimension was increased (>15.7 mm) in 93% cats. On radiographs left atrial enlargement (subjective assessment) was found in 48% (lateral view), 53% (ventrodorsal view), and 64% (any view) of cats whereas left atrial enlargement was absent in 36% of cats in both views. Agreement between both methods of left atrial size estimation was poor (Cohen's kappa 0.17). Receiver operating characteristic curve analysis identified a maximum echocardiographic left atrial dimension of approximately 20 mm as the best compromise (Youden index) between sensitivity and specificity in the prediction of radiographic left atrial enlargement. Left atrial enlargement as assessed by thoracic radiography may be absent in a clinically relevant number of cats with congestive heart failure. Therefore, normal left atrial size on thoracic radiographs does not rule out presence of left‐sided congestive heart failure in cats with clinical signs of respiratory distress.     

农村留守儿童交往问题的实证研究

通过自行编制的儿童交往量表,对2所农村初级中学和1所小学留守儿童进行抽样调查研究.结果表明,12个方面的交往特征上交往问题检测率分别为:亲情冷漠与憎恨占留守儿童数量的1.7%;孤独与郁闷占23.2%;受歧视占4.7%;亲情梦占51.0%;担忧与失眠占11.7%;学习辅导缺失占1.3%;受欺负与攻击占11.1%;放任与自暴自弃占14.8%;虚拟社区占2.3%;亲情管教缺失占9.4%;亲师占67.8%;疏远老师占17.1%;亲同学占84.9%;疏远同学占11.4%.留守儿童存在着比较严重的交往问题,最为典型的是亲情梦,孤独与郁闷,放任与自暴自弃,担忧与失眠,受欺负与攻击等.留守儿童的交往问题显著地受父母在外打工时间和回家间隔时间长短的影响,时间越长影响越严重.同时存在年级差异和性别差异,年级越低受到的影响越大,4年级留守儿童显著地在各个交往特征上受到最深重的影响.留守儿童女生比男生在交往交流问题上需要更多的关注和帮护.     

有机磷农药的检测思考

我校化学实验室首次开放，76名志愿者报名参加了这次探索性实验。以敌百虫为例阐述了有机磷农药检测原理、操作步骤，记录了实验数据并对它们进行了处理，总结出有机磷农药使用的最高限量和使用标准。     

Clinical vignette Fortuitous diagnosis of a persitent left cranial vena by color flow Doppler echocardiography in a dog

A persistent left cranial vena cava is described in an asymptomatic three-year-old female Shi Tzu. The purpose of this report is to show the value of color flow Doppler echocardiography in the diagnosis of this uncommon congenital cardiovasular abnormality.     

Effects of cardiac remodeling on atrial arrhythmogenesis in aged rabbit left atrium

AIM: To investigate the effects of myocardial remodeling of aged left atrium (LA) on atrial arrhythmogenesis in rabbits.METHODS: The male New Zealand rabbits were divided into young LA and aged LA groups. By observing the changes of monophasic action potential (MAP) and burst-pacing in LA of the rabbits in vivo, the main cardioelectrophysiological parameters such as resting membrane potential (RMP), action potential amplitude (APA), ma-ximum rise veloctiy of action potential (dv/dt_max), plateau potential and action potential duration at 30%, 50% and 90% (APD₃₀, APD₅₀ and APD₉₀), as well as the inducibility and duration of atrial arrhythmias were recorded. L-type calcium current (I_Ca,L) was analyzed via whole-cell patch-clamp technique in enzymatically dissociated single rabbit LA myocytes. The myocardial collagen content was quantified after Masson staining, and the ultrastructure of the LA cells was observed under scanning electron microscope. The expression of Cav1.2 in LA tissue of the 2 groups was detected by Western blot.RESULTS: Compared with young LA group, dv/dt_max and plateau potential were significantly decreased, APD₃₀ and APD₅₀ were shortened, and APD₉₀ was notably prolongated in aged LA group (P<0.01). The inducibility or duration of atrial arrhythmias was severely increased or prolongated in aged LA group (P<0.01). With voltage clamp model, the density of I_Ca,L in aged LA group was significantly decreased, and current-voltage curve was notably moved upward compared with young LA group. When the clamp potential was +20 mV, the density of I_Ca,L was notably modified from (11.72±1.39) pA/pF in young LA group to (6.08±0.98) pA/pF in aged LA group (P<0.01). Compared with young LA group, the protein level of collagen was significantly increased (P<0.01), and the arrange of atrial myocytes was irregular in LA of rabbits in aged LA group. The atrial myocytes of the LA wall in aged LA group exhibited abnormal ultrastructural alterations, such as karyopyknosis, irregular and swelling mitochondria with the presence of vacuoles, and mild and severe sarcomere degeneration. Compared with those in LA tissues of young rabbits, the expression levels of Cav1.2 in the LA tissues of aged rabbits were severely reduced (P<0.01), and had a significant positive correlation with the reduction of I_Ca,L (r=0.83, P<0.01).CONCLUSION: The pathophysiological characteristics of aged LA are significantly altered, and might contribute to vulnerability and susceptibility of occurrence of atrial fibillation in aged rabbits. The mechanisms might completely attribute to the notable reduction of I_Ca,L, abnormal alterations of ultrastructures and obvious decrease in the expression of Cav1.2 in the aged LA of aged rabbits.     

运动性和高血压性心脏肥大心肌间质胶原网络重塑及其对左心室功能的影响

目的：探讨运动性和高血压性心脏肥大大鼠心肌间质胶原网络的重塑及其对左心室功能的影响。方法：采用跑台训练方式和腹主动脉缩窄术分别建立运动性心肌肥大大鼠模型和高血压性心肌肥大大鼠模型。心脏离体灌注测定左心室功能;扫描电镜和透射电镜观察心肌胶原网络重构;通过羟脯氨酸测定心肌胶原的浓度;Western-blot进行Ⅰ型、Ⅲ型胶原分析。结果：高血压大鼠的平均动脉压始终较高（P<0.05）,而训练组大鼠的动脉血压始终较低（P<0.05）;高血压大鼠的心脏舒张速率低于训练组（P<0.05）;高血压性大鼠左心室羟脯氨酸的浓度明显升高（P<0.05）,而训练大鼠左心室羟脯氨酸浓度并没有显著升高;高血压大鼠的左心室Ⅲ型胶原与Ⅰ型胶原的比值下降明显（P<0.05）,而训练组大鼠并没有表现出相同的结果。结论：运动训练可以使大鼠心肌细胞与间质胶原同步增长,心脏功能提高,心肌舒缩性能增强;而慢性高血压性大鼠导致心肌细胞与间质胶原不成比例的增长,间质胶原过度增生,心脏功能受到损伤。心肌间质胶原网络的重塑对大鼠左心室功能具有重要影响。     

左右江革命老区扶贫攻坚的路径与成效探析——以贵州省荔波县月亮山区的大土苗族村为例

分析了地处左右江革命老区腹地的贵州省荔波县大土苗族村近30年来的科学造林、巧筑梯田、劈山修路和发展林下经济、开展乡村旅游、实施新农村建设等一系列扶贫举措及模式,探讨了大土村在反贫困斗争中因地制宜取得的成效及其成功经验。认为大土村的反贫困举措、扶贫模式、脱贫路径是极为成功的,在当今精准扶贫、精准脱贫的决胜会战实践中具有一定的应用价值与参考借鉴意义。因此,对其扶贫攻坚的路径、成效、经验进行梳理和分析,目的是希望有助于整个左右江革命老区和中西部贫困地区农村的精准脱贫与同步小康建设的推进。     

Heat stress in rat adriamycin cardiomyopathy: heat shock protein 25 and Myosin accumulation

In order to evaluate the effects of hyperthermia on adriamycin cardiomyopathy and its relationship with heat shock protein induction and myosin accumulation, female Sprague-Dawley rats (21-24 days) were randomized into four groups: the control, adriamycin, temperature and temperature-adriamycin groups. Adriamycin was injected i.v. at a dose of 27 mg/Kg (0.1 ml). The rats were exposed to a temperature of 45oC for 35 min, followed by a recovery (1 h) at room temperature prior to adriamycin treatment. Body weight was recorded weekly. The thickness of the ventricular wall and percentage of cellular damage were biometrically and ultrastructurally evaluated, respectively. Heat shock protein 25 and myosin accumulation were determined through Western blot analysis. The determinations were carried out monthly until the third month after treatment. At eight and twelve weeks after treatment, the thickness of the ventricular wall seemed to decrease in the adriamycin-treated rats in relation to the other groups. An electron microscopic analysis of the adriamycin group's left ventricular wall samples, showed more sarcomeric changes and loss of myofibrils than the control, temperature and temperature-adriamycin groups. At 24 hours after treatment with adriamycin, higher levels of heat shock protein 25 and myosin were observed (week 0) in the temperature-adriamycin group than in the control and adriamycin groups (4, 8 and 12 weeks). Hyperthermia was confirmed by a multivariate approach to induce heat shock protein 25 and myosin, which would strengthen cardiac-sarcomeric myosin arrangement.     

植物耐荫性研究进展

植物为适应荫蔽的环境，导致在叶片形态，解剖构造，叶绿体结构与运动，光合色素含量及光量子产额，光合作用单位，电子传递等方面产生变化或特化，以保证在弱光量子照射条件下仍能充分利用光能，维持生长所需的能量平衡，进行正常的生命活动。