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991.
ATP敏感性钾通道在预缺血对麻醉家兔缺血心肌保护中的作用 总被引:14,自引:2,他引:12
在氨基甲酸乙酯和戊巴比妥钠两种不同麻醉的家兔心肌缺血-再灌注模型,观察了ATP敏感性钾通道开发剂cromaklim(Cro)和预缺血(IP)对血流动力学和心肌梗塞范围的影响,旨在阐明KATP通道是否与IP对IR心肌的保护机制。 相似文献
992.
K. Akiyama T.L. Gluckman A. Terhakopian P.M. Jinadasa S. Narayan S. Singaswamy B. Massey III R.J. Bing 《Tissue & cell》1997,29(6):733-743
We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions. 相似文献
993.
结扎兔冠状动脉前降支与左室支的急性心肌梗塞比较 总被引:6,自引:0,他引:6
本文比较了结扎兔冠状动脉前降支(LAD组)和左室支(LVA组)两种方法建立的急性心肌梗塞模型。结果发现1:ECG标测,三天内不同时间LVA组∑△ST升高毫伏数均高于LAD组(P<0.01或P<0.05);2:N-BT染色,LVA组心肌梗塞占心室重的百分率为17.3%±0.56%,而LAD组为8.2%±2.42%,两者相差非常显著(P<0.01),证实了LVA组心梗面积较LAD组大且相对稳定。采用增强(Gd-DTPA)磁共振成像(MRI)扫描发现LVA组急性心梗范围在三天内基本稳定。作者认为,兔急性心梗模型采用结扎LVA优于结扎LAD。 相似文献
994.
缺氧条件下冻伤对大鼠微循环血液灌流量的影响 总被引:1,自引:1,他引:0
本文采用体重200±20g健康雄性Wistar大鼠,随机分为平原冻伤(FN)组、急性缺氧冻伤(FAH)组和缺氧习服缺氧冻伤(FHAC)组,实验观察了大鼠右后肢重度冻伤前后各组大鼠双后肢皮肤微循环灌流量的改变。结果表明,平原冻伤使大鼠双后肢微循环灌流量明显减少,提示局部重度冻伤对微循环的影响不只局限于冻区也涉及到对侧肢体。冷冻前FAH组大鼠微循环灌流量已明显低于FN组,表明急性缺氧时血容量进行代偿性的再分配,使微循环灌流量减少;FAH组大鼠冻后双后肢微循环灌流量的改变结果提示急性缺氧可加重其冻伤对微循环的损伤程度。FHAC组大鼠冻前微循环灌流量非常明显地低于正常对照,也明显低于急性缺氧对照,表明缺氧习服可造成微循环障碍;FHAC组大鼠冻肢微循环灌流量非常明显地低于FN组,提示缺氧习服加重高原冻伤引起的微循环障碍。 相似文献
995.
缺氧对右心室最大心肌血流量的影响 总被引:4,自引:0,他引:4
为了探讨缺氧对冠状血管贮备力的影响,我们观察了缺氧时大鼠血流动力学及右心室最大心肌血流量的变化。结果表明,急性缺氧引起PaO2、心输出量及氧运送量降低,但右心室心肌血流量增加,右心室最大与安静血流量比值降低。慢性缺氧时PaO2降低,血球比积和右心室重量指数增加,氧运送量和右心室血流量正常,但最大血流量降低,小动脉增厚、外膜胶元增加。以上结果提示,慢性缺氧对冠状血管贮备减少可能是小动脉壁增厚、外膜胶元增加和血液粘滞性增加及右心室肥大的结果。 相似文献
996.
化石研究的新技术──激光扫描共聚焦显微系统 总被引:2,自引:1,他引:2
激光扫描共聚焦显微技术的根本特性在于任何时候都将照明光与探测到物体表面的光限制在物体某一个相同点上。如果这个点非常小又在极小衍射范围内,那么激光扫描共聚焦成像系统的分辨率要比任何传统显微镜高许多。通过变换焦距,可做一系列虚拟断层切面。利用这个特点,对那些用常规手段无法进行切片磨面的微体化石采用激光扫描共聚焦新技术进行研究,获得了对小壳化石、昆虫、孢粉等化石研究的新成果。 相似文献
997.
998.
H Piepenbrink J Frahm A Haase D Matthaei 《American journal of physical anthropology》1986,70(1):27-28
Clinical applications of nuclear magnetic resonance (NMR) imaging have demonstrated its great potential for noninvasive examinations of soft tissues. Here preliminary experiments are reported on mummified human tissue by means of NMR cross-sectional and transmission imaging. For this purpose the natural viscosity of the tissues has been lowered by rehydration with an aqueous solution of 20% acetone. 相似文献
999.
Benedetta Boari Raffaella Salmi Massimo Gallerani Anna Maria Malagoni Fabio Manfredini Roberto Manfredini 《Biological Rhythm Research》2007,38(3):155-167
Convincing evidence has demonstrated that cardiovascular diseases do not occur randomly throughout the day, the week, or the year but show a well defined temporal organization. This article will review circadian, weekly, and seasonal patterns of occurrence of acute myocardial infarction, along with their underlying pathophysiological triggering factors. 相似文献
1000.
Anastasia Nikolopoulou Theodosia Maina Petros Sotiriou Paul Cordopatis Berthold A. Nock 《Journal of peptide science》2006,12(2):124-131
Two somatostatin analogues, [99mTc]Demotide and [99mTc]Demotate 4, were compared with [99mTc]Demotate 1, a previously reported somatostatin receptor subtype 2 (sst2) targeting tracer. Conjugates were prepared by coupling an open‐chain tetraamine chelator to D ‐Phe1 of [Tyr3]‐octreotide or [Tyr3]‐octreotate, respectively, via a p‐benzylaminodiglycolic acid spacer adopting solid‐phase peptide synthesis techniques. Peptide conjugates were collected in a highly pure form after chromatographic purification. Eventually, [99mTc]Demotide and [99mTc]Demotate 4 were obtained in ~1 Ci/µmol specific activity and >96% purity after labeling under alkaline conditions. Demotide and Demotate 4 exhibited similar high binding affinities for the sst2 expressed in AR4‐2J cells with IC50 values 0.16 and 0.10 nM, respectively. The (radio)metallated analogues [99mTc]Demotide and [99mTc]Demotate 4 showed equally high affinities to the sst2 during saturation binding assays in AR4‐2J cell membranes (Kds 0.08 and 0.07 nM, respectively). During incubation at 37 °C with AR4‐2J cells, the radiopeptides internalized effectively via a receptor‐mediated process, with [99mTc]Demotate 4 exhibiting a faster internalization rate than [99mTc]Demotide. After injection in athymic mice bearing sst2‐expressing AR4‐2J tumors, the radiotracers showed high and specific uptake in the tumor (>25%ID/g at 1 h) and in the sst2–positive organs. However, both [99mTc]Demotide and [99mTc]Demotate 4 showed unfavorably higher background activity, especially in the abdomen, in comparison to [99mTc]Demotate 1 and are, therefore, less suited than [99mTc]Demotate 1 for sst2‐targeted tumor imaging in man. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. 相似文献