| Photothrombotic Induction of Capillary Ischemia in the Mouse Cortex during in vivo Two-Photon Imaging
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Author:
Date:
2017-07-05
[Abstract] Photothrombosis of blood vessels refers to the activation of a circulating photosensitive dye with a green light to induce clotting in vivo (Watson et al., 1985). Previous studies have described how a focused green laser could be used to noninvasively occlude pial arterioles and venules at the brain surface (Schaffer et al., 2006; Nishimura et al., 2007; Shih et al., 2013). Here we show that small regions of the capillary bed can similarly be occluded to study the ischemic response within the capillary system of the mouse cerebral cortex. The advantage of this approach is that the ischemic zone is restricted to a diameter of approximately 150-250 μm. This permits higher quality two-photon imaging of degenerative processes that would be ...
[摘要] 血管的血栓形成是指用绿光激活循环的光敏染料，以在体内诱发凝血（Watson等人，1985）。以前的研究已经描述了如何将聚焦的绿色激光器用于非侵入性地封闭脑表面的小动脉和小静脉（Schaffer等人，2006; Nishimura等人， 2007; Shih等人，2013）。这里我们显示毛细血管床的小区域可以类似地闭塞，以研究小鼠大脑皮质毛细管系统内的缺血反应。这种方法的优点是缺血区被限制在约150-250μm的直径。这允许退化过程的更高质量的双光子成像，否则由于过度的光子散射，否则难以用大规模中风的模型来可视化。毛细血管闭塞的结果是血脑屏障（BBB）的泄漏。在这里，通过使用双光子成像数据集，我们展示了如何通过确定静脉内染料外渗的空间范围和定位来量化毛细血管渗漏。
【背景】存在许多动物模型通过闭塞主要大脑动脉大规模诱发缺血（Carmichael，2005）。然而，在体内双光子成像中不能获得中风的一些方面。在经历更严重缺血的区域，由于离子不平衡而导致细胞膨胀，这种水肿过程有助于增加光散射，大大降低了体内双光子成像的质量和深度。较小的局部缺血区域将减少光子散射，并且仍然允许与局部缺血相关的神经血管变化随着时间的推移在体内更清晰地显现。
我们最近表明，空间受限区域的缺血可以通过聚焦的血栓形成的皮质毛细血管床照射产生（Underly等人，2017）。毛细血管闭塞是高度可重复的，可以针对特定的位置，并通过颅骨成像窗口在精确的时间开始。所得到的缺血区域占据通过典型颅窗可接近的面积的1％（图1D和1E），允许在一个窗口中检查多个笔触。 ...
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| Measuring Rat Serum Osmolality by Freezing Point Osmometry
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Author:
Date:
2016-10-05
[Abstract] Blood serum or plasma osmolality is the measure of electrolyte to water balance in the body’s circulation, and is tightly regulated in physiological states in order to maintain normal levels of serum solute (Bourque, 2008). Osmolality is defined as the number of osmoles of solute per kg of water (mOsm/kg) (Dufour, 1993) and can be measured using different techniques that rely on the colligative properties of the solution. The most commonly used in lab settings are vapour pressure and freezing point osmometry, which are relatively quick and easy to perform. Freezing point osmometry is preferred because it is insensitive to volatile compounds, such as alcohol, that may be present in the solution. Measurement of serum or plasma osmolality is clinically relevant for a number of conditions and ...
[摘要] 血清或血浆渗透压是体内循环中电解质与水平衡的量度，并且在生理状态下受到严格的调节，以维持血清溶质的正常水平（Bourque，2008）。重量摩尔渗透压浓度定义为每公斤水溶质渗透摩尔数（mOsm / kg）（Dufour，1993），并且可以使用依赖于溶液的碰撞性质的不同技术来测量。实验室设置中最常用的是蒸气压和凝固点渗透压测量法，它们相对快速且易于执行。凝固点渗透压是优选的，因为它对溶解中可能存在的挥发性化合物（例如醇）不敏感。血清或血浆渗透压的测量在许多病症和疾病方面具有临床意义，包括高钠血症，糖尿病酮症酸中毒和不良抗生素综合征（Ellison，2013; Lupsa和Inzucchi，2013; Reddi，2013）。在本协议中，我们描述了使用冰点渗透压测定技术测量大鼠血清渗透压的方法，原先在我们以前在败血症中的渗透调节扰动研究中概述（Stare等，2015）。
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| Targeted Occlusion of Individual Pial Vessels of Mouse Cortex
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Author:
Date:
2013-09-05
[Abstract] Targeted photothrombosis is a method to occlude individual arterioles and venules that lie on the surface of the cerebral cortex. It has been used to study collateral flow patterns within the pial vascular network following occlusion of single surface vessels (Schaffer et al., 2006; Blinder et al., 2010; Nguyen et al., 2011), as well as to generate localized ischemic strokes following occlusion of single penetrating vessels (Nishimura et al., 2007; Drew et al., 2010; Shih et al., 2013). The intravascular clot is formed by irradiation of a target vessel with a focused green laser after injection of a circulating photosensitizing agent, Rose Bengal (Watson et al., 1985). We briefly describe modifications of custom-designed and ...
[摘要] 目标光血栓形成是阻塞位于大脑皮质表面上的个体小动脉和小静脉的方法。它已经用于在封闭单表面血管后研究在Pial血管网内的侧支血流模式（Schaffer等人，2006; Blinder等人，2010; Nguyen 2011），以及在单一穿透血管闭塞后产生局部缺血性中风（Nishimura et al。，2007; Drew et al。 ，2010; Shih et al。，2013）。在注射循环的光敏剂，玫瑰红（Watson等人，1985）后，通过用聚焦的绿色激光器照射目标血管形成血管内凝块。我们简要介绍了定制设计和商业双光子成像系统的修改，引入绿色激光用于光血栓形成。我们进一步提供如何闭塞麻醉鼠标的体感皮层内的单个穿透小动脉的说明。
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