A radioimmunoassay for parathyroid hormone is described that circumvents some previous difficulties. Parathyroid hormone binds strongly to other serum components. Consequently, a “control” curve is set up for each specimen, the specimen consisting of serum, diluent, and radiolabel, but no antibody. Final calculations are then based on the difference between the control curve and the curve obtai...

Generations of microbiologists have pondered over the issue of bacterial activity and whether most bacteria in the environment are “active,” “inactive,” or “dormant” (Stevenson 1978). This is a question with clear practical implications, in terms of food, sanitary, and clinical microbiology, as well as profound ecological implications. The issue started to be debated in earnest within the aquat...

Compounds 8a-d have been designed as bioisosters of tariquidar for imaging P-gp expression and density by PET. The results displayed that compounds 8b and 8d could be considered potential P-gp/BCRP ligands suitable as (11)C and (18)F radiotracers, respectively.

OBJECTIVE Radiotracers targeting prostate-specific membrane antigen (PSMA) have increasingly been recognized as showing uptake in a number of normal structures, anatomic variants, and non-prostate-cancer pathologies. We aimed to explore the frequency and degree of uptake in peripheral ganglia in patients undergoing PET with the PSMA-targeted agent 18F-DCFPyL. METHODS A total of 98 patients wh...

Levels of endothelin-1 (ET-1) are elevated in many disease states, although its total body kinetics of elimination are poorly understood. Therefore, it remains uncertain whether the presence of elevated levels of ET-1 in the setting of disease are secondary to changes in production or clearance or some combination thereof. Using a 125I-labeled ET-1 infusion technique, the volume of distribution...

The key function of the heart, a well-orchestrated series of contractions, is controlled by cardiac action potentials. These action potentials are initiated and propagated by a single isoform of voltage gated sodium channels - SCN5A. However, linking changes in SCN5A expression levels to human disease in vivo has not yet been possible. Radiocaine, an F-18 radiotracer for positron emission tomog...

UNLABELLED The chemokine stromal-derived factor-1alpha (SDF-1alpha, CXCL12) and its receptor CXCR4 are implicated as key mediators of hematopoietic stem cell retention, cancer metastasis, and HIV infection. Their role in myocardial infarction (MI) is not as well defined. The noninvasive in vivo quantitation of CXCR4 expression is central to understanding its importance in these diverse processe...

UNLABELLED (11)C-choline and (18)F-fluoromethylcholine ((18)F-FCH) have been used in patients to study tumor metabolic activity in vivo; however, both radiotracers are readily oxidized to respective betaine analogs, with metabolites detectable in plasma soon after injection of the radiotracer. A more metabolically stable FCH analog, (18)F-fluoromethyl-[1,2-(2)H4]choline ((18)F-D4-FCH), based on...