Mechanism of localization of /sup 99m/Tc-labeled pyrophosphate and tetracycline in infarcted myocardium
The gross and subcellular localizations of /suJm/Tc-labeled pyrophosphate and tetracycline in myocardial infarcts were studied in a rabbit model. Experiments utilizing double-nuclide labeling were carried out using a useful mapping technique. Concentration of the various chelates decreases in an expected manner from the center of the infarcted area toward its periphery, but it is higher near the epicardial surface than toward the endocardium. Technetium-99m-pyrophosphate is concentrated in the same infarcted areas as /sup 45/Ca ion or /sup 32/P-pyrophosphate, but to a much greater degree. The uptake is dependent on both the degree of necrosis and residual blood flow. Gel filtration experiments with rabbit serum indicate that /sup 99m/Tc-tagged pyrophosphate, tetracycline, and diphosphonate are mainly protein-bound, whereas /sup 32/P-pyrophosphate is not. Subcellular localization studies show that /sup 99m/Tc-tetracycline and /sup 99m/Tc-pyrophosphate are bound primarily to soluble protein, and only a small fraction is associated with nuclei, mitochondria, and microsomes. The uptake of technetium chelates in myocardial infarcts may be due to the formation of polynuclear complexes with denatured macromolecules rather than to the deposition of calcium in mitochondria.
- Research Organization:
- Tufts Univ., Boston
- OSTI ID:
- 7187503
- Journal Information:
- J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 17:7; ISSN JNMEA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Tc-99m HMDP (hydroxymethylene diphosphonate): a radiopharmaceutical for skeletal and acute myocardial infarct imaging. II. comparison of Tc-99m hydroxymethylene diphosphonate (HMDP) with other technetium-labeled bone-imaging agents in a canine model
Dual radionuclide study of myocardial infarction. Relationships between myocardial uptake of potassium-43, technetium-99m stannous pyrophosphate, regional myocardial blood flow, and creatine phosphorokinase depletion
Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
ANTIBIOTICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL LOCALIZATION
BIOLOGICAL MODELS
CARDIOVASCULAR DISEASES
CELL CONSTITUENTS
CHELATES
COMPLEXES
DIAGNOSIS
DISEASES
DRUGS
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MITOCHONDRIA
MYOCARDIAL INFARCTION
NECROSIS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
OXYGEN COMPOUNDS
PATHOLOGICAL CHANGES
PHOSPHONATES
PHOSPHORUS COMPOUNDS
PROTEINS
PYROPHOSPHATES
RADIOISOTOPES
TECHNETIUM 99
TECHNETIUM ISOTOPES
TETRACYCLINES
YEARS LIVING RADIOISOTOPES