Basal Metabolism of Intraperitoneally Injected Carrier-Free ⁷⁴As-Labeled Arsenate in Rabbits

Abstract

74As]arsenate metabolites in Flemish Giant rabbits was investigated. As absorbed rapidly, reaching maximal concentrations in plasma and packed cells after 30 min and 2 hr, respectively. As species is lower than that in other rabbits and more similar to that of humans. The tissue 74 As distribution varied widely with the highest concentrations in kidneys, liver, and lungs. 74As accumulated in bone whereas other tissues and blood showed rapid clearance rates. In muscle and heart an important part of arsenic was associated with components insoluble in phosphate-buffered isotonic saline. Binding of arsenic to soluble tissue proteins was most important in the kidneys, liver, and spleen. [ The biotransformation of arsenic in humans and other mammals is dependent on the chemical form administered. Arsenate and arsenite are methylated in vivo initially into monomethylarsonic acid (MMA) and subsequently to dimethylarsenic acid (DMA) (Tarn et al., 1979a;Yamauchi and Yamamura, 1983). This methylation process can be seen

Arsenic Binding to Proteins

“…Since the heme moiety strongly absorbs light at 420 nm, simultaneous detection of both 74 As and the heme moiety after size exclusion chromatography (SEC) revealed that arsenic was bound to hemoglobin in packed blood cells of rabbits intraperitoneally injected with 74 As-labeled arsenate. 204 This binding was also observed in the red blood cells of rats, as SEC showed that the 74 As was predominantly associated with a protein that had a molecular mass of ∼60 kDa and a strong absorption band at 420 nm. 209 To study potential arsenic binding partners in serum, cation and anion exchange separation schemes with fast protein liquid chromatrography were applied to serum that had been incubated in vitro with 74 As-labeled arsenate.…”

“…204 Up to 18% of total plasma 74 As was found to bind to transferrin. Similarly, a transferrin-specific affinity column was used to further confirm the identity of transferrin in serum of patients on continuous ambulatory peritoneal dialysis.…”

Real‐time tumor tracking using implanted positron emission markers: Concept and simulation study

“…Potentially useful isotopes are 124 I ͑T 1/2 = 4.2 days͒, 74 As ͑T 1/2 = 17.8 days͒, and 84 Rb ͑T 1/2 = 32.7 days͒. These isotopes have already been used for PET imaging [24][25][26][27][28] and are commercially available.…”

Detector development for positron emission based real-time tumor tracking

“…The optimal gating parameters were selected to be 10 ps gate width and 100V gating voltage. Before applying the gating voltage, a few spectra of our positron emission source, 22 These results indicate that with our optimized gating parameters, the gating circuit is operating in a way that the performance of our detector unit is still as good and system electronics are not as disturbed.…”

“…After the calibration, the following setup was arranged to evaluate the localization ability of PeTrack prototype and algorithm. As shown in figure 5.1.1, two 22 Na sources were placed 2.54 cm away from each other on a rotating disk. Both data acquisition systems were set to only record the coincidence events (coincidence window was open for 35 ns).…”