Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo.
Tissue-type plasminogen activator (t-PA) effectively lyses active thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m (99mTc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. 99mTc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. 99mTc-labeled human serum albumin was not retained at clot sites. Systemically administered 99mTc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear.
Takahashi
A
A
Department of Neurosurgery, Hokkaido University School of Medicine, Sapporo.
Itoh
K
K
Tsukamoto
E
E
Furudate
M
M
Kamiyama
H
H
Abe
H
H
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000503:physiopathology; D002415:Cats; D002533:Cerebral Angiography; D005337:Fibrin / Q000378:metabolism; D007275:Injections, Intravenous; D002542:Intracranial Embolism and Thrombosis / Q000139:chemically induced / Q000175:diagnosis* / Q000503:physiopathology; D011851:Radioactivity; D012709:Serum Albumin / Q000378:metabolism; D017556:Technetium Compounds / Q000097:blood / Q000493:pharmacokinetics; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*
D012709:Serum Albumin; D017556:Technetium Compounds; D005337:Fibrin; D010959:Tissue Plasminogen Activator