MONITORING A SIDS MODEL IN NEONATAL SWINE

拟议研究的长期目标是评估 心脏机制在猝死病因中的作用 婴儿死亡综合征(SIDS)。因此，这个项目直接关系到 这是婴儿生存和健康的问题。《公约》的具体目标 拟议的研究旨在检验这样一种假设： 心脏神经支配的发育异常可减少脑室 电稳定，有利于心源性猝死的发生。这个 研究设计和手术方法已经在 上一次赠款期间；因手术导致不平衡的新生猪 在心脏中，将持续监测自主神经支配(24 小时。)在出生后的八周内。那些幸存下来的和类似的 手术准备好的窝产仔将(在2，4，6，8周龄)进行测试 心血管反应：(I)缺氧，(Ii)高碳酸血症，(Iii) 心肺感受器的刺激，以及(Iv) 压力感受器传入信息。从这些研究中获得的结果 可能的诱发因素应该揭示出增加的 有猝死风险的新生儿的易感性。睡眠是最重要的 新生儿的主要行为状态与脑电睡眠的个体发育 可以通过连续的脑电记录来监测新生儿的病情。我们计划 检查作为VCR磁带确定的状态的函数的心电记录 行为、隔膜肌电和脑电，并将这些变量相互关联 对年龄和去神经类型都有不利影响。心脏的非线性分析 婴儿的心率变异性显示了复杂性的增加 成熟度和我们自己的结果也包括在小猪身上的类似发现。 这项拨款提案将追寻这些发现以及 关于这种复杂性的选择性心脏去神经，相关结果 在失去神经的小猪身上突然死亡。这样的研究应该证实 我们关于心脏神经支配重要性的工作假说 在婴儿猝死的病因学上。因此，我们正在 假定效应器水平异常，即心脏异常 水平，具体地说：心脏正常神经的成熟 以及它的反射控制。

The long-term objective of the proposed research is to evaluate the role of cardiac mechanisms in the etiology of sudden death in the Sudden Infant Death Syndrome (SIDS). Thus this project is directly related to a problem in infant survival and health. The specific aims of the proposed research are designed to test the hypothesis that a developmental anomaly in cardiac innervation could reduce ventricular electrical stability and favor the onset of sudden cardiac death. The research design and surgical methods have been worked out in the previous grant period; newborn swine with surgically induced imbalance in cardiac autonomic innervation will be continuously monitored (24 hrs.) throughout eight postnatal weeks. Those surviving and similarly surgically prepared littermates will be tested (at ages 2,4,6,8 wks) for cardiovascular responses to: (i) hypoxia, (ii) hypercapnia, (iii) stimulation of cardiopulmonary receptors, and (iv) alterations in baroreceptor afferent inputs. Results obtained from study of these possible precipitating factors should reveal the increased susceptibility of the neonate at risk for sudden death. Sleep is the predominant behavioral state of the neonate and ontogeny of EEG sleep in neonates can be monitored by serial EEG recordings. We plan to examine ECG recordings as a function of state determined by VCR tapes of behavior, diaphragmatic EMG and EEG, and correlate these variables against both age and type of denervation. Nonlinear analysis of heart rate variability in infants has revealed an increase in complexity with maturation and our own results included similar findings in piglets. This grant proposal would pursue these findings and the effects of selected cardiac denervation on this complexity, correlating results with sudden death in denervated piglets. Such studies should confirm our working hypothesis regarding the importance of cardiac innervation in the etiology of sudden death in infants. We are, therefore, postulating an abnormality at the effector level, i.e., at the cardiac level, specifically: maturation of the normal innervation of the heart and its reflex control.