/sup 13/N-labeled L-amino acids for in vivo assessment of local myocardial metabolism
The hot cell synthesis of sterile, pyrogen-free /sup 13/N-labeled L-amino acids was accomplished by employing the appropriate immobilized enzymes on a CNBr-activated Sepharose support and using remote, semiautomated systems. The syntheses were completed 6-12 min after cyclotron production of (/sup 13/N)ammonia. Myocardial time-activity curves after intracoronary injection of /sup 13/N-labeled L-amino acids in dogs were triexponential in both normal and ischemic myocardium. Higher retention of /sup 13/N activity was observed in ischemic segments. Positron computed tomography imaging also showed increased uptake of /sup 13/N-labeled L-glutamate and L-alanine in ischemic segments compared with normal myocardium when blood flow corrections were made. Myocardial transaminases are primarily responsible for the observed retention fractions. It suggests the participation of the carbon skeletons of these amino acids in the Krebs cycle.
- OSTI ID:
- 5515909
- Journal Information:
- J. Med. Chem.; (United States), Journal Name: J. Med. Chem.; (United States) Vol. 24:6; ISSN JMCMA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL LOCALIZATION
BLOOD FLOW
BODY
CARBOXYLIC ACIDS
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
CHEMICAL PREPARATION
COUNTING TECHNIQUES
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
DIAGNOSTIC USES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
HEART
ISCHEMIA
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MINUTES LIVING RADIOISOTOPES
MUSCLES
MYOCARDIUM
NITROGEN 13
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PATHOLOGY
RADIOISOTOPE SCANNING
RADIOISOTOPES
RADIONUCLIDE KINETICS
SCINTISCANNING
SYNTHESIS
USES
VASCULAR DISEASES