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Development of a method for simultaneous measurement of blood flow and blood gases

血流和血气同时测量方法的开发

基本信息

批准号：
07557191
负责人：
MORIMOTO Taketoshi
金额：
$ 0.45万
依托单位：
Kyoto Prefectural University of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07557191/
关键词：
micro-circulation blood flow fluorescence liposome partial pressure of oxygen

项目摘要

A novel method to measure blood flow and blood gases simultaneously in vivo was developed. This method is based on in vivo fluorometry of chemical substances sensitive to physiological parameters such as blood gases, blood temperature, pH and so on. The fluorescent dye was encapsulated in liposomes so as to administer into blood circulation. The liposome was also used to measure blood flow velocity using transit time method.Multilamellar liposome was fabricated from phosphatydylcholine using reverse-phase evaporation methods. Addition of cholesterol enabled to sustain fluorescent chemicals well, and activated methoxypolyethylene glycol reduced uptake of liposome by reticulo-endothelial system. The size of liposome was standardized using polycarbonate membrane filter. When liposome with less than 8mum of diameter were used, the flow velocity observed in mesenteric vessel showed no difference with that observed with erythrocytes. The administration of this liposome caused no embolism and toxicity for at least a week.The optical system finally attained after several trials is as follows : argon-laser was used modulating with Acousto-Optic modulator, exciting and signal laser was transferred with plastic optical fibers, and the fluorescence intensity was determined using photon counting. Since the relaxation time of the fluorescence is related to the oxygen concentration by Stern-Volmer equation, exygen tension of liposome suspension was determined from the lifetime of the signal light. Using this system we measured successfully the partial pressure of oxygen in vitro experiment and also in vivo experiment using anesthetized rat.The application of this system for the continuous monitoring of physiological parameters including CO_2 tension, and local temperature are underway.

提出了一种同时测量体内血流量和血气的新方法。这种方法是基于对生理参数（如血气、血液温度、pH值等）敏感的化学物质的体内荧光测定法。将荧光染料包封在脂质体中，使其进入血液循环。脂质体也被用来测量血液流速用过境时间法。以磷脂酰胆碱为原料，采用反相蒸发法制备了多层脂质体。添加胆固醇可以很好地维持荧光化学物质，并且激活甲氧基聚乙二醇可以减少网状内皮系统对脂质体的摄取。采用聚碳酸酯膜滤器对脂质体的大小进行标准化。当使用直径小于8mum的脂质体时，肠系膜血管流速与红细胞流速无明显差异。这种脂质体的施用在至少一周内没有引起栓塞和毒性。经过多次试验，最终得到的光学系统是：氩气激光用声光调制器调制，激励和信号激光用塑料光纤传输，荧光强度用光子计数测定。由于荧光的弛豫时间与氧浓度通过Stern-Volmer方程相关，因此脂质体悬浮液的氧张力由信号光的寿命来确定。利用该系统，我们在体外实验和麻醉大鼠体内实验中成功地测量了氧分压。该系统在连续监测co2浓度和局部温度等生理参数方面的应用正在进行中。