In vivo imaging and spectroscopy of pH and thiols status

描述(由申请人提供)： 这项提议将为P.I.提供新的培训和职业方向的重大转变，从基础物理化学和有机化学领域转向应用生物医学成像和光谱学领域。研究将在俄亥俄州立大学生物医学光谱和成像中心进行，这是一个独特的培训环境，采用了新兴的最先进技术，并提供了额外的实验生理学和细胞生物学方面的学习机会，将确保在独立于P.I.方面取得进展。整个实验计划将为P.I.及其同事先前合成的一组对pH和硫醇(SH)敏感的氮氧化物开发新的生物医学成像和光谱应用。现有的生物组织和生物体中pH和SH的时空检测方法要么有很大的局限性，要么根本不存在。因此，这些新的方法可能代表着在各种环境下的生理监测方面的突破。实验将重点放在与心脏缺血和缺血再灌注损伤相关的应用上。其具体目的是：(SA1)对现有的和新合成的pH和SH敏感的氮氧化物作为体内电子顺磁共振(EPR)应用的功能探针进行批判性评估。将研究功能敏感性、对生物组织还原的稳定性以及体内/细胞分布的能力。还将测试一系列专门为增强这些探测器属性而设计的新探测器。(SA2)开发基于EPR的功能性光谱和成像，用于研究活组织中时间和空间分辨的pH和SH含量。初步研究将优化探头管理技术，最大化空间和强度分辨率，并将毒性降至最低。这些实验计划使用这些技术来评估一个新的假设：即在预适应过程中，pH诱导的心肌缓冲能力的变化在随后的长时间缺血中对心脏的功能保护是重要的。初步实验证明了这一相对未知的机制的潜在重要性。(Sa3)在成像和医学方面获得必要的工具和技能，以便在物理化学、应用生物医学和成像技术之间建立联系。该项目的成功可能会对未来生物成像在医学上的应用产生重大影响。

DESCRIPTION (provided by applicant): This proposal will provide new training and a significant shift in career direction for the P.I. from fields of fundamental physical and organic chemistry to applied biomedical imaging and spectroscopy. Studies will be performed at the OSU Biomedical Spectroscopy and Imaging Center, a unique training environment with emerging state-of-the art techniques and with additional learning opportunities in experimental physiology and cell biology that will ensure progress toward independence of the P.I. The overall experimental plan will develop new biomedical imaging and spectroscopy applications for a group of pH- and thiol (SH)-sensitive nitroxides, previously synthesized by the P.I. and colleagues. Current methods for spatial and temporal detection of pH and SH in living tissues and organisms either have significant limitations or do not exist. Therefore, these new approaches could represent a breakthrough in physiologic monitoring in a variety of settings. Experiments will focus on applications related to cardiac ischemia and ischemia-reperfusion injury. The specific aims are: (SA1) To critically evaluate existing and newly synthesized pH- and SH-sensitive nitroxides as functional probes for in vivo electron paramagnetic resonance (EPR) applications. Functional sensitivity, stability towards reduction in biological tissues and capacity for in vivo/cellular distribution will be studied. A series of new probes will also be tested which are specifically designed to enhance these probe attributes. (SA2) To develop functional EPR-based spectroscopy and imaging for the investigation of time and spatially-resolved pH and SH content in living tissues. Initial studies will optimize techniques for probe administration, maximization of spatial and intensity resolution and minimization of toxicity. The experiments are planned using these techniques to evaluate a new hypothesis: namely, that pH-induced changes in myocardial buffering capacity, developed during preconditioning, are important in functional protection of the heart during subsequent prolonged ischemia. Preliminary experiments demonstrate the potential importance of this relatively unknown mechanism. (SA3) To obtain the necessary tools and skills in imaging and in medical science to bridge the interface between physical chemistry, applied biomedical sciences and imaging technology. The success of this project may have a significant impact on the future of bioimaging applications to medicine.