An automated method to control preload by compensation for stress relaxation in spontaneously contracting, isometric rat mesenteric lymphatics.
An automated method to control preload by compensation for stress relaxation in spontaneously contracting, isometric rat mesenteric lymphatics.
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一种通过补偿自发收缩、等长大鼠肠系膜淋巴管中的应力松弛来控制前负荷的自动化方法。
DOI：
10.1080/10739680701436152
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Zawieja,DavidC
中科院分区：
文献类型：
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作者：
Davis,MichaelJ;Lane,MeganM;Scallan,JoshuaP;Gashev,AnatoliyA;Zawieja,DavidC
目的：设计一种自动校正等长大鼠肠系膜血管（90-120 μm，ID）应力松弛的系统。应力松弛是一个特殊的问题，在等距研究的高度扩张的血管，是明显的，作为一个时间依赖性，二次下降后，突然长度增加的力量。由于相位收缩模式的phase-contraction是非常敏感的变化，在预负荷，应力松弛，使稳定的收缩模式难以实现和analyzed.Methods：DMT线肌描记器进行了修改，以适应尺蠖压电堆栈串联与标准的微米驱动器，允许自动控制的血管口径/力。的myograph的力输出被数字化和计算机算法被设计成伺服控制力通过改变vessel diameter.Results：该系统进行了测试，对被动pharmatics，被动小静脉，和pharmatics表现出自发的力瞬变。该软件被设计为在自发力瞬变期间暂时禁用伺服控制。对于主动和被动的atmohatics，稳定的预负荷保持得很好，表明该系统是足够的补偿应力relaxation.Conclusions：该方法工作良好，等距大鼠肠系膜atmohatics不干扰自发活动。其应适用于从其他组织和种属分离的动脉、静脉和淋巴管（直径80-500 μm）。
Objective:Our objective was to devise a system to automatically correct for stress relaxation of isometric rat mesenteric lymphatics (90–120 μm, ID). Stress relaxation is a particular problem in isometric studies of highly distensible vessels and is evident as a time-dependent, secondary decline in force after an abrupt length increase. Because the phasic contraction pattern of lymphatics is exquisitely sensitive to changes in preload, stress relaxation makes stable contraction patterns difficult to achieve and analyze.Methods:A DMT wire myograph was modified to accommodate an Inchworm piezo stack in series with a standard micrometer drive to permit automated control of vessel caliber/force. The force output of the myograph was digitized and computer algorithms were devised to servo control force by changing vessel diameter.Results:The system was tested on passive lymphatics, passive small veins, and lymphatics exhibiting spontaneous force transients. The software was designed to temporarily disable servo control during a spontaneous force transient. For both active and passive lymphatics, stable preloads were very well maintained, indicating that the system was adequately compensating for stress relaxation.Conclusions:The method works well with isometric rat mesenteric lymphatics without disturbing spontaneous activity. It should be applicable to arterial, venous, and lymphatic vessels (80–500 μm in diameter) isolated from other tissues and species.