Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two techniques for labeling of albumin with copper-67 (67Cu) and 62Cu were investigated; one using the native Cu(II) binding site of the protein and the other employing a bifunctional chelate, 6-bromoacetamidobenzyl-1,4,8,11-tetraazacyclotetradecane- N,N'N",N"'-tetraacetic acid (Br-benzyl-TETA or BAT), conjugated to the protein. Rat biodistribution experiments with 67Cu demonstrated retention of i.v. 67Cu-benzyl-TETA-albumin in the blood pool identical to co-injected 125I-albumin. By contrast, i.v. administration of either [67Cu]-Cu-acetate or [67Cu]-Cu-acetate pre-mixed with albumin results in relatively rapid clearance of blood-pool radioactivity as the tracer is excreted into the urine. The 62Cu-benzyl-TETA-albumin radiopharmaceutical was obtained in ca. 17% radiochemical yield (end of synthesis, without decay correction) following a procedure that can be completed in 15-18 min. In PET experiments with a baboon, myocardial blood volume images with 62Cu-benzyl-TETA-albumin were identical to those obtained with C15O. Use of the 62Cu-benzyl-TETA-albumin image for blood-pool subtraction of a 62Cu-PTSM myocardial perfusion image is illustrated. Copper-62-benzyl-TETA-HSA should be a useful, generator-produced radiotracer for the detection of the vascular pool at PET facilities without cyclotrons.
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PMID:In vivo comparison of copper blood-pool agents: potential radiopharmaceuticals for use with copper-62. 200 56

62Cu(T1/2 = 9.8 min) is a generator-produced positron-emitting radionuclide with a half-life amenable to blood-pool imaging with PET. Three bifunctional chelates [cyclic anhydride of diethylenetriaminepentaacetic acid (cDTPAA), 6-bromoacetamidobenzyl-1,4,8,11-tetraazacyclotetradecane-N,N ',N", N"'-tetraacetic acid (BAT), and p-carboxyethylphenylglyoxal-bis-(4N-methyl-thiosemicarbazone (CE-DTS)] were conjugated to HSA and labeled with 67Cu. The labeling efficiency of 67Cu-DTS-HSA was > 90%, whereas the labeling yields of 67Cu-DTPA-HSA and 67Cu-benzyl-TETA-HSA were less than 70%. Blood clearance and biodistribution of these three 67Cu-labeled conjugates were determined in rats. Of the three 67Cu-labeled bifunctional chelate-HSA conjugates, 67Cu-benzyl-TETA-HSA remained in the blood pool the longest, achieving stable blood levels at times longer than 24 h post-injection. The 67Cu radioactivity cleared the blood within 60 min post-injection of 67Cu-DTS-HSA, and within 10 min after administration of 67Cu-DTPA-HSA, indicating the dissociation of Cu2+ from these conjugates. Copper-labeled DTS-HSA achieved stable blood concentrations for at least 30 min post-injection and was therefore evaluated as a vascular imaging agent. DTS-HSA and benzyl-TETA-HSA were labeled with 62Cu and administered to a dog for blood-pool imaging using PET. Images were nearly identical to an image taken after administration of C15O. Because of the high labeling efficiency, DTS-HSA can be labeled with 62Cu without purification, making it more practical than 62Cu-benzyl-TETA-HSA as a blood-pool imaging agent.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of copper-labeled bifunctional chelate-albumin conjugates for blood pool imaging. 850 88