BILIRUBIN ENCEPHALOPATHY--MODELS AND METABOLIC STUDIES

这项建议的主要目标是发展候选人的 基础研究技能，同时深入了解病理生理学和 核黄素与胆红素毒性的作用机制。通过课程作业， 讨论和监督调查，了解将在 细胞新陈代谢和生理学水平特别适合 新生儿学和发育生物学的临床研究员。 这项建议的科学目标是为了理解 基本核黄斑的潜在细胞损伤仍不清楚。 虽然主要与胎儿红母细胞增生症有关，但核黄体肿大 此前，已在15%-25%的尸检新生儿中发现了这种病毒。这个 核黄体症的发生不仅取决于血清中的 未结合的胆红素；明显与白蛋白结合和 血脑屏障至少是影响胆红素的两个缓解因素 受伤。以前的模型已经被开发来确定什么是 核黄蜂的特征性组织病理学和行为学改变。 然而，包括我们自己在内的以前的研究表明，其中一些 在这些模型中只产生一过性胆红素脑病(TBE) 动物。在体外，胆红素已被证明对许多细胞有毒性。 许多不同类型细胞的功能。这些毒性中的哪一种 核黄蜂中的主要成分是已知的；确定这取决于 体内和体内可比较的生理功能障碍的证明 体外模型。 这项拟议的研究计划最初发展并具有不同的特点 核黄体动物模型，包括溶血诱导模型 模拟与核黄蜂相关的溶血条件。 组织病理学和行为学观察将确定核黄体损伤。 核黄体损伤将表现为神经生理学、磁学 共振成像和光谱学研究，包括能量评估 新陈代谢发生变化。使用这些生理和代谢标记物， 文中还将研究核黄龙和白蜡虫的异同。 体内研究还将检查降低胆红素的治疗方法 生产和它们预防核黄蜂的能力。 体外研究将进一步评估胆红素对神经源性细胞的毒性 细胞。能量代谢的磁共振波谱研究将 允许直接与核黄蜂的体内动物模型进行比较 我们计划的研究发现了大脑能量代谢的变化。这将是 帮助验证该模型在胆红素进一步研究中的使用 毒性。后续研究将评估蜂窝环境，包括 PH和白蛋白浓度，因为它影响胆红素毒性 细胞。最后，胆红素毒性的调查将包括化验。 离子通道对膜生理的影响。这些频道都很好- 在神经母细胞瘤细胞中具有特征，但不受胆红素的影响。如果 必要时，计划开发备用细胞系，用于In 胆红素毒性的体外研究。

The prime objective of this proposal is to development of the candidate's skills in basic research while gaining insight into the pathophysiology and mechanisms of kernicterus and bilirubin toxicity. By coursework, discussions and supervised investigation, understanding will be gained in cellular metabolism and physiology at a level particularly appropriate for a clinical investigator in neonatology and developmental biology. The scientific objective of this proposal is aimed at understanding the still obscure underlying cellular injuries fundamental kernicterus. Kernicterus, although primarily associated with erythroblastosis fetalis previously, has been found in 15-25% of autopsied newborns. The development of kernicterus depends on not only on serum level of unconjugated bilirubin; apparently binding to albumin and integrity of the blood-brain barrier are at least two mitigating factors affecting bilirubin injury. Prior models have been developed to determine what are the characteristic histopathologic and behavioral changes of kernicterus. However, previous studies including our own have shown that some of these models produce only a transient bilirubin encephalopathy (TBE) in these animals. In vitro, bilirubin has been shown to be toxic to many cellular functions of many different types of cells. Which of these toxicities predominates in kernicterus is known; determining this depends upon demonstration of comparable physiologic dysfunction in both in vivo and in vitro models. This proposed research plan initially develops and characterizes different animal models of kernicterus, including a hemolysis-induced model simulating hemolytic conditions associated with kernicterus. Histopathology and behavioral observations will define kernicterus injury. Kernicterus injury will then be characterized by neurophysiology, magnetic resonance imaging and spectroscopy studies, including evaluation of energy metabolism changes. Using these physiologic and metabolic markers, similarities and distinction between kernicterus and TBE will be studied. In vivo studies will also examine therapies to decrease bilirubin production and their ability to prevent kernicterus. In vitro studies will further evaluate bilirubin toxicity on neural-derived cells. Magnetic resonance spectroscopy studies of energy metabolism will allow direct comparison to in vivo animal models of kernicterus and the brain energy metabolism changes seen by our planned studies. This will help validate the use of this model for further studies of bilirubin toxicity. Subsequent studies will evaluate cellular environment including pH and albumin concentration, as it affects bilirubin toxicity in these cells. Finally, investigation of bilirubin toxicity will include assaying effects on membrane physiology of ion channels. These channels are well- characterize in neuroblastoma cells but not as affected by bilirubin. If necessary, contingencies are planned to develop alternate cell lines for in vitro studies of bilirubin toxicity.