These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: 99mTc-MAEC complexes: new renal radiopharmaceuticals combining characteristics of (99m)Tc-MAG3 and (99m)Tc-EC.
    Author: Taylor AT, Lipowska M, Hansen L, Malveaux E, Marzilli LG.
    Journal: J Nucl Med; 2004 May; 45(5):885-91. PubMed ID: 15136640.
    Abstract:
    UNLABELLED: 99mTc-Mercaptoacetyltriglycine ((99m)Tc-MAG3) and (99m)Tc-L,L-ethylenedicysteine ((99m)Tc-LL-EC) are useful renal radiopharmaceuticals; however, both agents have renal clearances less than that of (131)I-orthoiodohippurate ((131)I-OIH), and (99m)Tc-LL-EC exists in dianionic and monoanionic forms at physiologic pH. In an effort to develop a superior (99m)Tc agent with a rapid clearance comparable with that of (131)I-OIH, we have designed a new ligand system, mercaptoacetamide-ethylene-cysteine (MAEC), which combines important structural features of both MAG3 and EC. METHODS: Biodistribution and clearance studies were performed on Sprague-Dawley rats using syn- and anti-(99m)Tc-L- and -D-MAEC coinjected with (131)I-OIH. Studies were also performed by coinjecting each isomer ( approximately 74 MBq [ approximately 2 mCi]) and 7.4-11.1 MBq (200-300 micro Ci) of (131)I-OIH in 3 volunteers with dual-isotope imaging performed using a camera system fitted with a high-energy collimator. Blood samples were obtained from 3 to 90 min after injection and urine samples were obtained at 30, 90, and 180 min. RESULTS: In the rats, <10% of the injected dose remained in the blood at 10 min after injection for all isomers, and the urine dose at 60 min ranged from 84% to 99% that of (131)I-OIH. The clearances of syn- and anti-(99m)Tc-L-MAEC in the rats were higher than the clearances for the D-isomers (P <or= 0.02) and were 102% and 105% that of (131)I-OIH, respectively. In humans, the plasma protein binding of the (99m)Tc-MAEC complexes ranged from 82% to 89%. All 4 complexes provided excellent renal images. The (99m)Tc-MAEC complex/(131)I-OIH plasma clearance ratio in humans ranged from 45% (anti-(99m)Tc-L-MAEC) to 74% (syn-(99m)Tc-D-MAEC) with the 180-min urine excretion equivalent to that of (131)I-OIH for all 4 complexes. CONCLUSION: Initial data in humans suggest that syn-(99m)Tc-D-MAEC has a higher clearance than that of (99m)Tc-MAG3; however, none of the (99m)Tc-MAEC tracers have a clearance equivalent to that of (131)I-OIH and further ligand design is needed.
    [Abstract] [Full Text] [Related] [New Search]