PHOTODYNAMICS OF ULTRAVIOLET EPIDERMAL CHROMOPHORES

描述：（改编自申请人的摘要）压倒性的 有证据表明，过度暴露于太阳的紫外线（UV） 辐射抑制免疫反应，这可以促进肿瘤 生长和皮肤癌的风险。 暴露于紫外线辐射也 引起皮肤的多种组织学反应， 在替代真皮基质中胶原的弹性纤维中， 糖胺聚糖、胶原蛋白交联和表皮 增厚 这些过程开始皮肤中的天然发色团 吸收太阳辐射。 该提案描述了一项研究计划， 旨在研究两种表皮发色团的光反应性 尿刊酸和黑色素。 该项目的具体目标是：（a） 测量产生单线态的体外作用谱 分子氧后，激发反式尿刊酸， 确定该测量的作用谱是否定量地符合 任何已报道的各种组织学的体内作用谱 皮肤对UV暴露的反应，（B）开发综合模型 对于顺式- 尿刊酸及其各种作用光谱的测定 （c）建立一个全面的模式， 合成和天然黑色素的光谱学和光化学，以及 (d)研究药物分子如何与黑色素结合， 药物和色素的光动力学。

DESCRIPTION: (Adapted from the applicant's abstract) Overwhelming evidence indicates that excess exposure to the sun's ultraviolet (UV) radiation suppresses the immune responses, which can promote tumor growth and the risk of skin cancer. Exposure to UV radiation also causes a variety of histological responses in skin including an increase in elastic fibers replacing the collagen in the dermal matrix, an increase in glycosaminoglycans, collagen cross-linking, and epidermal thickening. These processes begin when natural chromophores in skin absorb solar radiation. This proposal describes a research program directed at studying the photoreactivity of two epidermal chromophores urocanic acid and melanin. The specific goals of the project are (a) to measure the in vitro action spectrum for the generation of singlet molecular oxygen following the excitation of trans-urocanic acid and to determine if this measured action spectrum quantitatively agrees with any of the reported in vivo action spectra for various histological responses of skin to UV exposure, (b) to develop a comprehensive model for the spectroscopy and wavelength-dependent photoreactivity of cis- urocanic acid and to determine action spectra for its various photochemical processes, (c) to develop a comprehensive model for the spectroscopy and photochemistry of synthetic and natural melanins, and (d) to study how drug molecules bound to melanin affect the photodynamics of both the drug and pigment.