Biological mechanism of action of the potential myocardial perfusion imaging agent tr-(99m-Tc(DMPE)/sub 2/Cl/sub 2/)/sup +/

Conference · Wed May 01 00:00:00 EDT 1985 · J. Nucl. Med.; (United States)

OSTI ID:6795754

Vanderheyden, J L; Deutsch, E

This study was undertaken to probe the biological mechanism of action of the cationic complex tr-(99m-Tc(DMPE)/sub 2/-Cl/sub 2/)/sup +/ (DMPE = 1,2-bis(dimethylphosphino)ethane), and specifically to assess whether or not in vivo reduction of this species to the neutral analog tr-(99mm-Tc(DMPE)/sub 2/Cl/sub 2/)/sup 0/ occurs. This assessment was made through the use of the rhenium analog tr-(186-Re(DMPE)/sub 2/)Cl/sub 2/)/sup +/ which has identical size, shape, charge and lipophilicity, but is 190 mV more difficult to reduce. The two related complexes (M(DMPE)/sub 3/)/sup +/ (M=Tc,Re) were also prepared as a control set since neither of these agents can be reduced to a neutral form. Qualitative imaging studies in dogs, and quantitative tissue distribution studies in rats, show that (99m-Tc(DMPE)/sub 3/)/sup +/ and (186-Re(DMPE)/sub 3/)/sup +/ have identical biological behavior, but that tr-(99m-Tc(DMPE)/sub 2/Cl/sub 2/)/sup +/ and tr-(186-Re(DMPE)/sub 2/Cl/sub 2/)/sup +/ and tr-(186-Re(DMPE)/sub 2/Cl/sub 2/)/sup +/ have markedly dissimilar biodistributions. When the two control complexes are co-injected into rats, the ratio of Tc-99m to Re-186 activity in all tissues is essentially 1.0. However, when tr-(99m-Tc(DMPE)/sub 2/)Cl/sub 2/)/sup +/ and tr-(186-Re(DMPE)/sup 2/-Cl/sub 2/)/sup +/ are co-injected into rats the Tc-99m/Re-186 ratio varies from one tissue to the next (from 0.14 to 6.0). Highest ratios are observed in organs of the RES, supporting the conclusion that tr-(99m-Tc(DMPE)/sub 2/Cl/sub 2/)/sup +/ is reduced in vivo to the neutral analog (which behaves as a colloid) whereas tr-(186-Re(DMPE)/sub 2/)Cl/sub 2/)/sup +/ is not reduced in vivo. This in vivo reduction of tr-(99m-Tc(DMPE)/sub 2/Cl/sub 2/)/sup +/ detracts from the utility of this cationic agent by promoting transfer of radioactivity from the heart to the liver.

• Research Organization: Univ. of Cincinnati, Cincinnati, OH
• OSTI ID: 6795754
• Report Number(s): CONF-850611-; TRN: 87-010627
• Journal Information: J. Nucl. Med.; (United States), Vol. 26:5; Conference: 32. annual meeting of the Society of Nuclear Medicine, Houston, TX, USA, 2 Jun 1985
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
59 BASIC BIOLOGICAL SCIENCES
HEART
RADIOCARDIOGRAPHY
RADIOISOTOPE SCANNING
LIVER
MYOCARDIUM
RADIOPHARMACEUTICALS
TISSUE DISTRIBUTION
UPTAKE
RETICULOENDOTHELIAL SYSTEM
RHENIUM COMPLEXES
TECHNETIUM COMPLEXES
CARBOXYLIC ACIDS
DOGS
LABELLING
METABOLISM
QUANTITATIVE CHEMICAL ANALYSIS
RATS
RHENIUM 186
SCINTISCANNING
TECHNETIUM 99
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARDIOGRAPHY
CARDIOVASCULAR SYSTEM
CHEMICAL ANALYSIS
COMPLEXES
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DISTRIBUTION
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GLANDS
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MUSCLES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
RHENIUM ISOTOPES
RODENTS
TECHNETIUM ISOTOPES
TISSUES
TRANSITION ELEMENT COMPLEXES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550501 - Metabolism- Tracer Techniques