John S. Vogel

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UNLABELLED A new technique was evaluated to identify changes in bone metabolism directly at high sensitivity through isotopic labeling of bone Ca. Six women with low BMD were labeled with 41Ca up to 700 days and treated for 6 mo with risedronate. Effect of treatment on bone could be identified using 41Ca after 4-8 wk in each individual. INTRODUCTION(More)
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic amine rodent carcinogen that is found at the ppb level in cooked meat. Most laboratory studies are at 10(4)-10(7)-fold greater concentrations than actual ingested human doses. We report the first study of the bioavailability and fate of this heterocyclic amine at a human dietary(More)
The growth of accelerator mass spectrometry as a tool for quantitative isotope ratio analysis in the biosciences necessitates high-throughput sample preparation. A method has been developed to convert CO(2) obtained from carbonaceous samples to solid graphite for highly sensitive and precise (14)C quantification. Septa-sealed vials are used along with(More)
We present a sensitive tracer method, suitable for in vivo human research, that uses beta-[(14)C]carotene coupled with accelerator mass spectrometry (AMS) detection. Using this approach, the concentration-time course of a physiological (306 microgram 200 nCi) oral dose of beta-[(14)C]carotene was determined for 209 days in plasma. Analytes included(More)
A drug delivery microelectromechanical systems (MEMS) device was designed to release complex profiles of multiple substances in order to maximize the effectiveness of drug therapies. The device is based on micro-reservoirs etched into a silicon substrate that contain individual doses of drug. Each dose is released by the electrochemical dissolution of the(More)
Accelerator mass spectrometry (AMS) traces isotopically labeled biochemicals and provides significant new directions for understanding molecular kinetics and dynamics in biological systems. AMS traces low-abundance radioisotopes for high specificity but detects them with MS for high sensitivity. AMS reduces radiation exposure doses to levels safe for use in(More)
Accelerator MS (AMS) provides a novel method for obtaining and analyzing pharmacokinetics and pharmacodynamics in children. This paper reviews the scientific and ethical rationale for AMS in pediatric trials, the regulatory framework and general considerations with some specific examples of pediatric clinical trials using AMS. Microdosing in the context of(More)
BACKGROUND The ability of beta-carotene to deliver bioactive retinoids to tissues is highly variable. A clearer understanding of the environmental and genetic factors that modulate the vitamin A potential of beta-carotene is needed. AIM OF STUDY Assess the vitamin A value of orally administered beta-carotene relative to a co-administered reference dose of(More)