Conductance to Measure Cardiac Mechanics

描述(申请人的逐字描述)：Left的申请 心室压力-容量关系的转基因小鼠精确到 衡量收缩能力的方法并不广泛。这笔赠款的长期目标是 就是量化完好小鼠的左心功能。测量 电导提供了一种产生瞬时余量的方法 脑室容量信号。目前可用的瞬时电导 输出是血液和左心室肌信号的组合，但 需要的是血容量(仅限)。这个问题可以通过使用两个方法来解决 同时频率，因为心肌电阻率随频率变化 而血液的电阻率则不是。 这项工作将证明双频电导系统是 优于标准单频系统。一种实验性的组合 研究和数值模型将被用来校准血容量 从组合的血液和肌肉信号中提取时的计算。最后， 提出了在仪器方面的进展，以将双频系统转移到 小鼠开胸准备，增强商业利益。 通过去除瞬时心肌对容量信号的贡献 在一过性下腔静脉阻断期间获得的，绝对的 测量左心室收缩能力将是可行的。这将会 扩大完整的小鼠左心室的血流动力学特征 由于压力-体积分析提供了丰富的信息。 建议的商业应用： 双频电导系统将使科学家能够精确地测量 心血管疾病转基因小鼠模型的复杂表型，如 充血性衰竭。对左心功能的量化也将使药物 该行业将在转基因小鼠中进行新药快速筛选。这些项目的时机 了解选定基因类型的表型的研究是理想的人类基因组 该项目接近完成；由于人类和小鼠共享高度保守的 与心血管功能相关的基因。

DESCRIPTION (Applicant's Description Verbatim): The application of left ventricular pressure-volume relationships to transgenic mice to precisely measure contractility is not widely available. The long-term goal of this grant is to quantify left ventricular function in the intact mouse. Measurement of electrical conductance offers a method to generate an instantaneous left ventricular volume signal. The presently available instantaneous conductance output is a combination of blood and left ventricular muscle signals, but the blood volume (only) is desired. The problem can be solved by using two simultaneous frequencies, since myocardial resistivity varies with frequency while blood resistivity does not. The work will demonstrate that the dual frequency conductance system is superior to the standard single frequency system. A combination of experimental studies and numerical models will be used to calibrate the blood volume calculation when extracted from the combined blood and muscle signal. Finally, advances in instrumentation are proposed to move the dual frequency system to a closed-chest mouse preparation to enhance commercial interest. By removing the instantaneous myocardial contribution to the volume signal obtained during transient occlusion of the inferior vena cava, absolute measures of left ventricular contractility would be available. This would broaden the hemodynamic profile available from the intact murine left ventricle due to the wealth of information provided by pressure-volume analysis. PROPOSED COMMERCIAL APPLICATION: A dual frequency conductance system would allow scientists to precisely measure the complex phenotype of transgenic murine models of cardiovascular disease, such as congestive failure. Quantitation of left ventricular function would also allow the pharmaceutical industry to perform rapid screenting of new durgs in transgenic mice. The timing for these studies to understand the phenotype of selected genotypes is ideal as the Human Genome Project nears completion; and since humans and mice share a subset of highly conserved genes related to cardiovascular function.