Time-dependent changes of lumped and rate constants in the deoxyglucose method in experimental cerebral ischemia.
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)
Nakai
H
H
Cone Neurosurgical Research Laboratory, Montreal Neurological Institute, McGill University, Quebec, Canada.
Yamamoto
Y L
YL
Diksic
M
M
Matsuda
H
H
Takara
E
E
Meyer
E
E
Redies
C
C
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000150:complications; D001158:Arteries; D002545:Brain Ischemia / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D002415:Cats; D002539:Cerebral Arterial Diseases / Q000150:complications; D002560:Cerebrovascular Circulation; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000097:blood / Q000378:metabolism*; D007700:Kinetics; D008722:Methods; D008959:Models, Neurological; D013997:Time Factors
D003837:Deoxy Sugars; D003847:Deoxyglucose