The retention, distribution, metabolism, and excretion of [(14)C]octamethylcyclotetrasiloxane (D(4)) were studied in Fischer 344 rats after single and multiple exposures to 7, 70, or 700 ppm [(14)C]D(4). Subset groups were established for body burden, distribution, and elimination. Retention of inhaled D(4) was relatively low (5-6% of inhaled D(4)). Radioactivity derived from [(14)C]D(4) inhala...

The natural (40K) and anthropogenic (137Cs) radioactivity concentration in four different typologies of early childhood (up to two years old) foods, i.e., homogenized fruit, meat, biscuits baby pasta, produced Italy sold Italian large retailers, was investigated through High Purity Germanium (HPGe) gamma spectrometry. present study is carried out with the aim to: (i) evaluate background levels ...

The metabolism and pharmacokinetics of moxonidine, a potent central-acting antihypertensive agent, were studied in four healthy subjects after a single oral administration of approximately 1 mg (approximately 60 muCi) of [(14)C(3)]moxonidine. Moxonidine was rapidly absorbed, with peak plasma concentration achieved between 0.5 to 2 h postdose. The maximal plasma concentration and the area under ...

UNLABELLED The potential of 76Br-bromodeoxyuridine as a PET tracer for characterizing proliferation potential was investigated in multicellular tumor aggregates and in healthy rats and pigs. METHODS Bromine-76-bromide was produced by proton irradiation of a 76Se-enriched target using a 17-MeV cyclotron and recovered by thermal diffusion. Bromine-76-BrdU was prepared from the corresponding tri...

UNLABELLED Studies in rodents indicate that the disruption of P-glycoprotein (P-gp) function increases drug distribution into the developing fetus and organs such as the brain. To simultaneously and serially evaluate the effect of P-gp activity and inhibition on the tissue distribution of drugs in a more representative animal model, we tested the feasibility of conducting whole-body PET of the ...

The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides...

The disposition and metabolism of isopropyl N-[(2S)-7-cyano-4-(2-pyridylmethyl)-2,3-dihydro-1H-cyclopenta[b]indol-2-yl]carbamate (LY2452473; a selective androgen receptor modulator) in humans was characterized after a single 15-mg (100 μCi) oral dose of [¹⁴C]LY2452473 to six healthy male subjects. LY2452473 was absorbed rapidly (time to reach maximum plasma concentration for both LY2452473 and ...

The dopamine agonist rotigotine was developed for the treatment of Parkinson's disease and restless legs syndrome. Disposition, metabolism, elimination, and absolute bioavailability of rotigotine were determined in six healthy male subjects by using two different forms of administration in a randomized sequence with a crossover design. Treatment A (continuous infusion) consisted of a single rad...

The distribution, excretion and biotransformation of 14C-cloxazolam were studied in rats and mice. The tissue concentration reached the maximum at about 1 and 3 hr after oral administration to rats and mice, respectively. The brain concentration was higher and lasted longer in mice than in rats. In the whole-body autoradiograms of mice, no significant radioactivity was detected in the tissues e...

The pharmacokinetics and placental transfer of a single dermal 10.0 mg (10microCi)/kg dose of uniformly phenyl-labeled [14C] methyl parathion (0,0-dimethyl 0-4-nitrophenyl phosphorothioate) were investigated in pregnant Sprague-Dawley rats at 14-18 days of gestation. Three rats were killed at each time interval: 1, 2, 4, 12, 24, 48, 72, and 96 h after dosing. Radioactivity disappeared biexponen...