Device development to measure cellular activity in brain

1. 快速扫描回波平面成像（EPI）方法被纳入到新开发的高灵敏度体内^<13>C核磁共振方法中，该方法是我们实验室通过将异核多重共振能力与临床成像相结合而开发的。用^<13>C标记的葡萄糖注射到活体器官中，用^ 1h -探测^<13>C NMR法无创追踪。葡萄糖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。这种快速成像技术可以在30分钟内获得大鼠脑中^<13> c标记的化合物。这些是作为前体的l-^<13> c -葡萄糖及其代谢产物，2-，3-和4-谷氨酰胺/谷氨酸。因此，对模型动物进行脑缺血期间代谢变化的跟踪研究是可行的。采用近红外光谱法监测无创血氧水平。为此，在chance博士的实验室开发了具有750和830nm光源和13通道检测器的分光光度计。用该仪器在30秒左右的时间内对大鼠脑缺血时的脱氧情况和血容量进行了跟踪，并绘制了脑缺血图。通过光谱和氧结合研究，证实了半no配体血红蛋白具有典型的t型结构。因此，这种血红蛋白可以作为一种有效的氧载体被利用到活组织的死亡部分。此外，这种血红蛋白的顺磁性可以用作磁共振成像的造影剂，它可以描绘活体动物的血管。

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.