Nakai H, Yamamoto Y L, Diksic M, Matsuda H, Takara E, Meyer E, Redies C
Cone Neurosurgical Research Laboratory, Montreal Neurological Institute, McGill University, Quebec, Canada.
J Cereb Blood Flow Metab. 1987 Oct;7(5):640-8. doi: 10.1038/jcbfm.1987.117.
Time-dependent changes in the lumped and rate constants in a bilateral middle cerebral artery (MCA) occlusion in cats were evaluated. These variables were measured in 11 cats after a sham operation, in five after a 1-h occlusion, in two after a 2-h occlusion, in five after a 4-h occlusion, and in four after a 16-h occlusion. The time course of the cerebral tissue radioactivity [Ci* (t)] was monitored by external coincidence counting during a programmed infusion of [18F]2-fluorodeoxyglucose (FDG). Arterial plasma concentration [Cp* (t)] of tracer was kept constant during the first 45 min. Comparison of k2* and k3* in the sham-operated group, estimated by external coincidence counting, and by the ratio of extraction fractions of glucose and [18F]2-FDG, demonstrated no significant difference between these rate constants in these two groups of animals. The rate and lumped constants were also estimated from Ci* (t) and Cp* (t), as well as from the ratio of extraction fractions of glucose and [18F]2-FDG, respectively, in the MCA occlusion group. Significant decrease in k3* was observed after 1 h of occlusion (20% lower than in the sham operation, p less than 0.05); in k1* decrease occurred within 4 h of occlusion (21% lower than in the sham operation, p less than 0.05). However, decrease in k2* was observed only after 16 h of occlusion (26% lower than in the sham operation, p less than 0.05). Namely, decrease of rate constants occurred first in k3* then in k1* and k2*.(ABSTRACT TRUNCATED AT 250 WORDS)
评估了猫双侧大脑中动脉闭塞时集总常数和速率常数随时间的变化。在11只猫进行假手术后、5只猫进行1小时闭塞后、2只猫进行2小时闭塞后、5只猫进行4小时闭塞后以及4只猫进行16小时闭塞后测量了这些变量。在程序性输注[18F]2-氟脱氧葡萄糖（FDG）期间，通过外部符合计数监测脑组织放射性[Ci*(t)]的时间进程。在前45分钟内，示踪剂的动脉血浆浓度[Cp*(t)]保持恒定。通过外部符合计数以及葡萄糖和[18F]2-FDG提取分数之比估算假手术组中的k2和k3，结果表明这两组动物的这些速率常数之间无显著差异。在大脑中动脉闭塞组中，还分别根据Ci*(t)和Cp*(t)以及葡萄糖和[18F]2-FDG提取分数之比估算了速率常数和集总常数。闭塞1小时后观察到k3显著降低（比假手术组低20%，p<0.05）；闭塞4小时内k1降低（比假手术组低21%，p<0.05）。然而，仅在闭塞16小时后观察到k2降低（比假手术组低26%，p<0.05）。也就是说，速率常数首先在k3中降低，然后在k1和k2中降低。（摘要截断于250字）
