Device development to measure cellular activity in brain

1.将快速扫描回波平面成像(EPI)方法引入本实验室新发展的高灵敏活体核磁共振方法中，该方法是在临床影像的基础上，结合异核多重共振能力而发展起来的。用~1H-检测~(13)&gt；C核磁共振方法无创地示踪~(13)&gt；C标记的葡萄糖进入活体器官。葡萄糖在体内达到最高水平后迅速下降，而葡萄糖代谢反应产生的谷氨酰胺/谷氨酸在1小时内达到最高水平，并在此高水平维持约2小时。这种快速成像技术使在30分钟内获得大鼠大脑中的~(13)C标记化合物成为可能。它们是作为前体的L-β-C-葡萄糖及其代谢物2-、3-和4-谷氨酰胺/谷氨酸。因此，在动物模型上跟踪脑缺血时的代谢变化是可行的。近红外光谱学被用来监测血液中的无创氧水平。为此，钱斯博士的实验室研制了一台具有750 nm和830 nm光源以及13个通道探测器的分光光度计。利用该仪器跟踪了大鼠脑缺血期间的氧合和血容量，并在大约30秒内构建了它们的地图。光谱分析和氧结合研究表明，半无配体血红蛋白具有典型的T-结构。因此，这种血红蛋白可以作为活组织中死亡部分的有效氧载体。此外，这种血红蛋白的顺磁性可以作为磁共振成像的造影剂，可以显示活体动物的血管。

1. Fast scanning echo planar imaging (EPI) approach was incorporated into newly developed highly sensitive in vivo ^<13>C NMR method, which was developed in our laboratory by the integration of hetero-nuclear multiple resonance capability with the basis of clinical imager.2. Injected glucose labeled by ^<13>C into living organs was traced non-invasively by ^1H-detected ^<13>C NMR method. Glucose reached to the highest level in and decreased rapidly, however, glutamine/glutamate derived by the metabolic reaction of the glucose reached to the highest level in 1 hour and stayed in a this high level for approximately two more hours.3. This fast imaging technique made it possible to obtain ^<13>C-labled chemical compounds in rat brain within 30 minute period. These were l-^<13>C-glucose as a precursor and its metabolites, 2-, 3-, and 4- glutamine/glutamate. Therefore, it is feasible to follow the metabolic change during brain ischemia in model animals.4. Near infra red spectroscopy was employed to monitor non-invasively oxygen level in blood. For this a spectrophotometer having 750 and 830nm light sources and 13 channel detector was developed in Dr.Chance's laboratory. With this instrument deoxygenation and blood volume were traced during brain ischemia in rat and their maps were also constructed in approximately 30 seconds.5. A half NO-liganded hemoglobin was elucidated to be in typical T-structure by spectroscopic and oxygen binding studies. Therefore, this hemoglobin may be utilized as an effective oxygen carrier to deceased part in living tissue. In addition, the paramagnetism of this hemoglobin may be used as a contrast reagent in MR imaging, which can delineate blood vessels in living animas.