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Chuang JC, Clifford AJ, Kim SH, Novotny JA, Kelly PB, Holstege DM, Walzem RL. Separation of Lipoproteins for Quantitative Analysis of 14C-Labeled Lipid-Soluble Compounds by Accelerator Mass Spectrometry. Int J Mol Sci 2024; 25:1856. [PMID: 38339135 PMCID: PMC10855872 DOI: 10.3390/ijms25031856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
To date, 14C tracer studies using accelerator mass spectrometry (AMS) have not yet resolved lipid-soluble analytes into individual lipoprotein density subclasses. The objective of this work was to develop a reliable method for lipoprotein separation and quantitative recovery for biokinetic modeling purposes. The novel method developed provides the means for use of small volumes (10-200 µL) of frozen plasma as a starting material for continuous isopycnic lipoprotein separation within a carbon- and pH-stable analyte matrix, which, following post-separation fraction clean up, created samples suitable for highly accurate 14C/12C isotope ratio determinations by AMS. Manual aspiration achieved 99.2 ± 0.41% recovery of [5-14CH3]-(2R, 4'R, 8'R)-α-tocopherol contained within 25 µL plasma recovered in triacylglycerol rich lipoproteins (TRL = Chylomicrons + VLDL), LDL, HDL, and infranatant (INF) from each of 10 different sampling times for one male and one female subject, n = 20 total samples. Small sample volumes of previously frozen plasma and high analyte recoveries make this an attractive method for AMS studies using newer, smaller footprint AMS equipment to develop genuine tracer analyses of lipophilic nutrients or compounds in all human age ranges.
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Affiliation(s)
| | | | - Seung-Hyun Kim
- Department of Applied Bioscience, College of Life and Environmental Science, Konkuk University, Seoul 143-701, Republic of Korea;
| | - Janet A. Novotny
- U.S. Department of Agriculture, Beltsville Human Nutrition Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705, USA;
| | - Peter B. Kelly
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Dirk M. Holstege
- UC Davis Analytical Lab, University of California, Davis, CA 95616, USA
| | - Rosemary L. Walzem
- Poultry Science Department, Graduate Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA
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2
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Takahashi RH, Malhi V, Liederer BM, Cho S, Deng Y, Dean B, Nugteren J, Yost E, Al-Sayah MA, Sane R, Kshirsagar S, Ma S, Musib L. The Absolute Bioavailability and Absorption, Metabolism, and Excretion of Ipatasertib, a Potent and Highly Selective Protein Kinase B (Akt) Inhibitor. Drug Metab Dispos 2023; 51:1332-1341. [PMID: 37524543 DOI: 10.1124/dmd.122.001175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 07/06/2023] [Accepted: 07/21/2023] [Indexed: 08/02/2023] Open
Abstract
Ipatasertib (GDC-0068) is a potent, highly selective, small-molecule inhibitor of protein kinase B (Akt) being developed by Genentech/Roche as a single agent and in combination with other therapies for the treatment of cancers. To fully understand the absorption, metabolism, and excretion of ipatasertib in humans, an open-label study using 14C-radiolabeled ipatasertib was completed to characterize the absolute bioavailability (period 1) and mass balance and metabolite profiling (period 2). In period 1, subjects were administered a 200 mg oral dose of ipatasertib followed by an 80 μg (800 nCi) intravenous dose of [14C]-ipatasertib. In period 2, subjects received a single oral dose containing approximately 200 mg (100 μCi) [14C]-ipatasertib. In an integrated analytical strategy, accelerator mass spectrometry was applied to measure the 14C microtracer intravenous pharmacokinetics in period 1 and fully profile plasma radioactivity in period 2. The systemic plasma clearance and steady-state volume of distribution were 98.8 L/h and 2530 L, respectively. The terminal half-lives after oral and intravenous administrations were similar (26.7 and 27.4 hours, respectively) and absolute bioavailability of ipatasertib was 34.0%. After a single oral dose of [14C]-ipatasertib, 88.3% of the administered radioactivity was recovered with approximately 69.0% and 19.3% in feces and urine, respectively. Radioactivity in feces and urine was predominantly metabolites with 24.4% and 8.26% of dose as unchanged parent, respectively; indicating that ipatasertib had been extensively absorbed and hepatic metabolism was the major route of clearance. The major metabolic pathway was N-dealkylation mediated by CYP3A, and minor pathways were oxidative by cytochromes P450 and aldehyde oxidase. SIGNIFICANCE STATEMENT: The study provided definitive information regarding the absolute bioavailability and the absorption, metabolism, and excretion pathways of ipatasertib, a potent, novel, and highly selective small-molecule inhibitor of protein kinase B (Akt). An ultrasensitive radioactive counting method, accelerator mass spectrometry was successfully applied for 14C-microtracer absolute bioavailability determination and plasma metabolite profiling.
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Affiliation(s)
- Ryan H Takahashi
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Vikram Malhi
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Bianca M Liederer
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Sungjoon Cho
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Yuzhong Deng
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Brian Dean
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - James Nugteren
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Edward Yost
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Mohammad A Al-Sayah
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Rucha Sane
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Smita Kshirsagar
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Shuguang Ma
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
| | - Luna Musib
- Drug Metabolism and Pharmacokinetics (R.H.T., B.M.L., S.C., Y.D., B.D., S.M.), Clinical Pharmacology (V.M., R.S., S.K., L.M.), BioAnalytical Sciences (J.N.), Small Molecule Pharmaceutics (E.Y.), and Small Molecule Analytical Chemistry (M.A.A.-S.), Genentech Inc., South San Francisco, California
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3
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Buchholz BA, Ahn KC, Huang H, Gee SJ, Stewart BJ, Ognibene TJ, Hammock BD. Pharmacokinetics, Metabolite Measurement, and Biomarker Identification of Dermal Exposure to Permethrin Using Accelerator Mass Spectrometry. Toxicol Sci 2021; 183:49-59. [PMID: 34460930 PMCID: PMC8404990 DOI: 10.1093/toxsci/kfab082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Impregnating military uniforms and outdoor clothing with the insecticide permethrin is an approach to reduce exposure to insect borne diseases and to repel pests and disease vectors such as mosquitos and sandflies, but the practice exposes wearers to prolonged dermal exposure to the pesticide. Key metabolite(s) from a low dose dermal exposure of permethrin were identified using accelerator mass spectrometry. Metabolite standards were synthesized and a high performance liquide chromatography (HPLC) elution protocol to separate individual metabolites in urine was developed. Six human subjects were exposed dermally on the forearm to 25 mg of permethrin containing 1.0 µCi of 14C for 8 h. Blood, saliva and urine samples were taken for 7d. Absorption/elimination rates and metabolite concentrations varied by individual. Average absorption was 0.2% of the dose. Serum concentrations rose until 12-24 h postdermal application then rapidly declined reaching predose levels by 72 h. Maximum saliva excretion occurred 6 h postdosing. The maximum urinary excretion rate occurred during 12-24 h; average elimination half-life was 56 h. 3-Phenoxybenzyl alcohol glucuronide was the most abundant metabolite identified when analyzing elution fractions, but most of the radioactivity was in still more polar fractions suggesting extensive degradative metabolism and for which there were no standards. Analyses of archived urine samples with the ultra performance liquid chromatography-accelerator mass spectrometry-mass spectrometry (UPLC-AMS-MS) system isolated a distinct polar metabolite but it was much diminished from the previous analyses a decade earlier.
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Affiliation(s)
- Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National laboratory, Livermore, California 94550, USA
| | - Ki Chang Ahn
- Department of Entomology, University of California, Davis, California, USA
| | - Huazhang Huang
- Department of Entomology, University of California, Davis, California, USA
| | - Shirley J Gee
- Department of Entomology, University of California, Davis, California, USA
| | - Benjamin J Stewart
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Ted J Ognibene
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National laboratory, Livermore, California 94550, USA
| | - Bruce D Hammock
- Department of Entomology, University of California, Davis, California, USA
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4
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Garrod MG, Rossow HA, Calvert CC, Miller JW, Green R, Buchholz BA, Allen LH. 14C-Cobalamin Absorption from Endogenously Labeled Chicken Eggs Assessed in Humans Using Accelerator Mass Spectrometry. Nutrients 2019; 11:nu11092148. [PMID: 31500393 PMCID: PMC6769442 DOI: 10.3390/nu11092148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 08/31/2019] [Accepted: 09/04/2019] [Indexed: 12/27/2022] Open
Abstract
Traditionally, the bioavailability of vitamin B-12 (B12) from in vivo labeled foods was determined by labeling the vitamin with radiocobalt (57Co, 58Co or 60Co). This required use of penetrating radioactivity and sometimes used higher doses of B12 than the physiological limit of B12 absorption. The aim of this study was to determine the bioavailability and absorbed B12 from chicken eggs endogenously labeled with 14C-B12 using accelerator mass spectrometry (AMS). 14C-B12 was injected intramuscularly into hens to produce eggs enriched in vivo with the 14C labeled vitamin. The eggs, which provided 1.4 to 2.6 μg of B12 (~1.1 kBq) per serving, were scrambled, cooked and fed to 10 human volunteers. Baseline and post-ingestion blood, urine and stool samples were collected over a one-week period and assessed for 14C-B12 content using AMS. Bioavailability ranged from 13.2 to 57.7% (mean 30.2 ± 16.4%). Difference among subjects was explained by dose of B12, with percent bioavailability from 2.6 μg only half that from 1.4 μg. The total amount of B12 absorbed was limited to 0.5–0.8 μg (mean 0.55 ± 0.19 μg B12) and was relatively unaffected by the amount consumed. The use of 14C-B12 offers the only currently available method for quantifying B12 absorption in humans, including food cobalamin absorption. An egg is confirmed as a good source of B12, supplying approximately 20% of the average adult daily requirement (RDA for adults = 2.4 μg/day).
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Affiliation(s)
- Marjorie G Garrod
- USDA, ARS Western Human Nutrition Research Center, Davis, CA 95616, USA.
| | - Heidi A Rossow
- Population Health and Reproduction, University of California, Davis, CA 95616, USA.
| | | | - Joshua W Miller
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Ralph Green
- Department. of Medical Pathology and Laboratory Medicine, University of California, Davis, Sacramento, CA 95817, USA.
| | - Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
| | - Lindsay H Allen
- USDA, ARS Western Human Nutrition Research Center, Davis, CA 95616, USA.
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5
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Carratt SA, Hartog M, Buchholz BA, Kuhn EA, Collette NM, Ding X, Van Winkle LS. Naphthalene genotoxicity: DNA adducts in primate and mouse airway explants. Toxicol Lett 2019; 305:103-109. [PMID: 30684585 DOI: 10.1016/j.toxlet.2019.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/05/2019] [Accepted: 01/20/2019] [Indexed: 01/14/2023]
Abstract
Naphthalene (NA) is a ubiquitous environmental pollutant and possible human carcinogen that forms tumors in rodents with tissue/regional and species selectivity. This study seeks to determine whether NA is able to directly adduct DNA in an ex vivo culture system. Metabolically active lung tissue was isolated and incubated in explant culture with carbon-14 labeled NA (0, 25, 250 μM) or 1,2-naphthoquinone (NQ), followed by AMS analyses of metabolite binding to DNA. Despite relatively low metabolic bioactivation in the primate airway, dose-dependent NA-DNA adduct formation was detected. More airway adducts were detected in female mice (4.7-fold) and primates (2.1-fold) than in males of the same species. Few adducts were detected in rat airway or nasal epithelium. NQ, which is a metabolic product of NA, proved to be even more potent, with levels of adduct formation 70-80-fold higher than seen when tissues were incubated with the parent compound NA. This is the first study to demonstrate NA-DNA adduct formation at a site of carcinogenesis, the mouse lung. Adducts were also detected in non-human primate lung and with a NQ metabolite of NA. Taken together, this suggests that NA may contribute to in vivo carcinogenesis through a genotoxic mechanism.
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Affiliation(s)
- Sarah A Carratt
- Center for Health and the Environment, University of California Davis, Davis, CA 95616, USA
| | - Matthew Hartog
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Bruce A Buchholz
- Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Edward A Kuhn
- Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | | | - Xinxin Ding
- College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA.
| | - Laura S Van Winkle
- Center for Health and the Environment, University of California Davis, Davis, CA 95616, USA; Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA.
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6
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Buchholz BA, Carratt SA, Kuhn EA, Collette NM, Ding X, Van Winkle LS. Naphthalene DNA Adduct Formation and Tolerance in the Lung. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS 2019; 438:119-123. [PMID: 30631217 PMCID: PMC6322674 DOI: 10.1016/j.nimb.2018.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Naphthalene (NA) is a respiratory toxicant and possible human carcinogen. NA is a ubiquitous combustion product and significant component of jet fuel. The National Toxicology Program found that NA forms tumors in two species, in rats (nose) and mice (lung). However, it has been argued that NA does not pose a cancer risk to humans because NA is bioactivated by cytochrome P450 monooxygenase enzymes that have very high efficiency in the lung tissue of rodents but low efficiency in the lung tissue of humans. It is thought that NA carcinogenesis in rodents is related to repeated cycles of lung epithelial injury and repair, an indirect mechanism. Repeated in vivo exposure to NA leads to development of tolerance, with the emergence of cells more resistant to NA insult. We tested the hypothesis that tolerance involves reduced susceptibility to the formation of NA-DNA adducts. NA-DNA adduct formation in tolerant mice was examined in individual, metabolically-active mouse airways exposed ex vivo to 250 μΜ 14C-NA. Ex vivo dosing was used since it had been done previously and the act of creating a radioactive aerosol of a potential carcinogen posed too many safety and regulatory obstacles. Following extensive rinsing to remove unbound 14C-NA, DNA was extracted and 14C-NA-DNA adducts were quantified by AMS. The tolerant mice appeared to have slightly lower NA-DNA adduct levels than non-tolerant controls, but intra-group variations were large and the difference was statistically insignificant. It appears the tolerance may be more related to other mechanisms, such as NA-protein interactions in the airway, than DNA-adduct formation.
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Affiliation(s)
- Bruce A Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Sarah A Carratt
- Center for Health and the Environment, University of California, Davis, CA USA
| | - Edward A Kuhn
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Nicole M Collette
- Bioscience and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Xinxin Ding
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ USA
| | - Laura S Van Winkle
- Center for Health and the Environment, University of California, Davis, CA USA
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7
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Nanotracing and cavity-ring down spectroscopy: A new ultrasensitive approach in large molecule drug disposition studies. PLoS One 2018; 13:e0205435. [PMID: 30332475 PMCID: PMC6192596 DOI: 10.1371/journal.pone.0205435] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022] Open
Abstract
New therapeutic biological entities such as bispecific antibodies targeting tissue or specific cell populations form an increasingly important part of the drug development portfolio. However, these biopharmaceutical agents bear the risk of extensive target-mediated drug disposition or atypical pharmacokinetic properties as compared to canonical antibodies. Pharmacokinetics and bio-distribution studies become therefore more and more important during lead optimization. Biologics present, however, greater analytical challenges than small molecule drugs due to the mass and selectivity limitation of mass spectrometry and ligand-binding assay, respectively. Radiocarbon (14C) and its detection methods, such as the emerging 14C cavity ring down spectroscopy (CRDS), thus can play an important role in the large molecule quantitation where a 14C-tag is covalently bound through a stable linker. CRDS has the advantage of a simplified sample preparation and introduction system as compared to accelerator mass spectrometry (AMS) and can be accommodated within an ordinary research laboratory. In this study, we report on the labeling of an anti-IL17 IgG1 model antibody with 14C propionate tag and its detection by CRDS using it as nanotracer (2.1 nCi or 77.7 Bq blended with the therapeutic dose) in a pharmacokinetics study in a preclinical species. We compare these data to data generated by AMS in parallel processed samples. The derived concentration time profiles for anti-IL17 by CRDS were in concordance with the ones derived by AMS and γ-counting of an 125I-labeled anti-IL17 radiotracer and were well described by a 2-compartment population pharmacokinetic model. In addition, antibody tissue distribution coefficients for anti-IL17 were determined by CRDS, which proved to be a direct and sensitive measurement of the extravascular tissue concentration of the antibody when tissue perfusion was applied. Thus, this proof-of-concept study demonstrates that trace 14C-radiolabels and CRDS are an ultrasensitive approach in (pre)clinical pharmacokinetics and bio-distribution studies of new therapeutic entities.
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8
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Enright HA, Falso MJS, Malfatti MA, Lao V, Kuhn EA, Hum N, Shi Y, Sales AP, Haack KW, Kulp KS, Buchholz BA, Loots GG, Bench G, Turteltaub KW. Maternal exposure to an environmentally relevant dose of triclocarban results in perinatal exposure and potential alterations in offspring development in the mouse model. PLoS One 2017; 12:e0181996. [PMID: 28792966 PMCID: PMC5549899 DOI: 10.1371/journal.pone.0181996] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/11/2017] [Indexed: 12/31/2022] Open
Abstract
Triclocarban (TCC) is among the top 10 most commonly detected wastewater contaminants in both concentration and frequency. Its presence in water, as well as its propensity to bioaccumulate, has raised numerous questions about potential endocrine and developmental effects. Here, we investigated whether exposure to an environmentally relevant concentration of TCC could result in transfer from mother to offspring in CD-1 mice during gestation and lactation using accelerator mass spectrometry (AMS). 14C-TCC (100 nM) was administered to dams through drinking water up to gestation day 18, or from birth to post-natal day 10. AMS was used to quantify 14C-concentrations in offspring and dams after exposure. We demonstrated that TCC does effectively transfer from mother to offspring, both trans-placentally and via lactation. TCC-related compounds were detected in the tissues of offspring with significantly higher concentrations in the brain, heart and fat. In addition to transfer from mother to offspring, exposed offspring were heavier in weight than unexposed controls demonstrating an 11% and 8.5% increase in body weight for females and males, respectively. Quantitative real-time polymerase chain reaction (qPCR) was used to examine changes in gene expression in liver and adipose tissue in exposed offspring. qPCR suggested alterations in genes involved in lipid metabolism in exposed female offspring, which was consistent with the observed increased fat pad weights and hepatic triglycerides. This study represents the first report to quantify the transfer of an environmentally relevant concentration of TCC from mother to offspring in the mouse model and evaluate bio-distribution after exposure using AMS. Our findings suggest that early-life exposure to TCC may interfere with lipid metabolism and could have implications for human health.
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Affiliation(s)
- Heather A. Enright
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
- * E-mail:
| | - Miranda J. S. Falso
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Michael A. Malfatti
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Victoria Lao
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Edward A. Kuhn
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Nicholas Hum
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Yilan Shi
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Ana Paula Sales
- Data Analytics and Decision Sciences, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Kurt W. Haack
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Kristen S. Kulp
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Bruce A. Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Gabriela G. Loots
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Graham Bench
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Kenneth W. Turteltaub
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
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9
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Kim A, Yu BY, Dueker SR, Shin KH, Kim HS, Ahn H, Cho JY, Yu KS, Jang IJ, Lee H. An Accelerator Mass Spectrometry-Enabled Microtracer Study to Evaluate the First-Pass Effect on the Absorption of YH4808. Clin Pharmacol Ther 2017; 102:537-546. [PMID: 28214288 DOI: 10.1002/cpt.672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/23/2017] [Accepted: 02/14/2017] [Indexed: 12/25/2022]
Abstract
14 C-labeled YH4808, a novel potassium-competitive acid blocker, was intravenously administered as a microtracer at 80 μg (11.8 kBq or 320 nCi) concomitantly with the nonradiolabeled oral drug at 200 mg to determine the absolute bioavailability and to assess the effect of pharmacogenomics on the oral absorption of YH4808. The absolute bioavailability was low and highly variable (mean, 10.1%; range, 2.3-19.3%), and M3 and M8, active metabolites of YH4808, were formed 22.6- and 38.5-fold higher after oral administration than intravenous administration, respectively. The product of the fraction of an oral YH4808 dose entering the gut wall and the fraction of YH4808 passing on to the portal circulation was larger in subjects carrying the variants of the CHST3, SLC15A1, and SULT1B1 genes. A combined LC+AMS is a useful tool to construct a rich and highly informative pharmacokinetic knowledge core in early clinical drug development at a reasonable cost.
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Affiliation(s)
- A Kim
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea.,Clinical Trial Center, Ajou University Medical Center, Suwon, Korea
| | - B-Y Yu
- Korea Institute of Science and Technology, Seoul, Korea
| | | | - K-H Shin
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Korea
| | - H S Kim
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea
| | - H Ahn
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea
| | - J-Y Cho
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea
| | - K-S Yu
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea
| | - I-J Jang
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea
| | - H Lee
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea.,Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
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10
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Burt T, John CS, Ruckle JL, Vuong LT. Phase-0/microdosing studies using PET, AMS, and LC-MS/MS: a range of study methodologies and conduct considerations. Accelerating development of novel pharmaceuticals through safe testing in humans – a practical guide. Expert Opin Drug Deliv 2016; 14:657-672. [DOI: 10.1080/17425247.2016.1227786] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Mortimer M, Petersen EJ, Buchholz BA, Orias E, Holden PA. Bioaccumulation of Multiwall Carbon Nanotubes in Tetrahymena thermophila by Direct Feeding or Trophic Transfer. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8876-85. [PMID: 27398725 PMCID: PMC4991038 DOI: 10.1021/acs.est.6b01916] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Consumer goods contain multiwall carbon nanotubes (MWCNTs) that could be released during product life cycles into the environment, where their effects are uncertain. Here, we assessed MWCNT bioaccumulation in the protozoan Tetrahymena thermophila via trophic transfer from bacterial prey (Pseudomonas aeruginosa) versus direct uptake from growth media. The experiments were conducted using (14)C-labeled MWCNT ((14)C-MWCNT) doses at or below 1 mg/L, which proved subtoxic since there were no adverse effects on the growth of the test organisms. A novel contribution of this study was the demonstration of the ability to quantify MWCNT bioaccumulation at low (sub μg/kg) concentrations accomplished by employing accelerator mass spectrometry (AMS). After the treatments with MWCNTs at nominal concentrations of 0.01 mg/L and 1 mg/L, P. aeruginosa adsorbed considerable amounts of MWCNTs: (0.18 ± 0.04) μg/mg and (21.9 ± 4.2) μg/mg bacterial dry mass, respectively. At the administered MWCNT dose of 0.3 mg/L, T. thermophila accumulated up to (0.86 ± 0.3) μg/mg and (3.4 ± 1.1) μg/mg dry mass by trophic transfer and direct uptake, respectively. Although MWCNTs did not biomagnify in the microbial food chain, MWCNTs bioaccumulated in the protozoan populations regardless of the feeding regime, which could make MWCNTs bioavailable for organisms at higher trophic levels.
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Affiliation(s)
- Monika Mortimer
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California 93106, United States
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia
| | - Elijah J. Petersen
- Biosystems and Biomaterials Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Bruce A. Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Eduardo Orias
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, United States
| | - Patricia A. Holden
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, California 93106, United States
- Corresponding Author. ; tel: 805-893-3195; fax: 805-893-7612
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12
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Kuhn HG, Eisch AJ, Spalding K, Peterson DA. Detection and Phenotypic Characterization of Adult Neurogenesis. Cold Spring Harb Perspect Biol 2016; 8:a025981. [PMID: 26931327 PMCID: PMC4772100 DOI: 10.1101/cshperspect.a025981] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Studies of adult neurogenesis have greatly expanded in the last decade, largely as a result of improved tools for detecting and quantifying neurogenesis. In this review, we summarize and critically evaluate detection methods for neurogenesis in mammalian and human brain tissue. Besides thymidine analog labeling, cell-cycle markers are discussed, as well as cell stage and lineage commitment markers. Use of these histological tools is critically evaluated in terms of their strengths and limitations, as well as possible artifacts. Finally, we discuss the method of radiocarbon dating for determining cell and tissue turnover in humans.
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Affiliation(s)
- H Georg Kuhn
- Institute for Neuroscience and Physiology, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Amelia J Eisch
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070
| | - Kirsty Spalding
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm SE-171 77, Sweden
| | - Daniel A Peterson
- Center for Stem Cell and Regenerative Medicine, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
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13
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Nallathamby PD, Mortensen NP, Palko HA, Malfatti M, Smith C, Sonnett J, Doktycz MJ, Gu B, Roeder RK, Wang W, Retterer ST. New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies. NANOSCALE 2015; 7:6545-55. [PMID: 25790032 PMCID: PMC4847546 DOI: 10.1039/c4nr06441k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nanomaterial based drug delivery systems allow for the independent tuning of the surface chemical and physical properties that affect their biodistribution in vivo and the therapeutic payloads that they are intended to deliver. Additionally, the added therapeutic and diagnostic value of their inherent material properties often provides extra functionality. Iron based nanomaterials with their magnetic properties and easily tailorable surface chemistry are of particular interest as model systems. In this study the core radius of the iron oxide nanoparticles (NPs) was 14.08 ± 3.92 nm while the hydrodynamic radius of the NPs, as determined by Dynamic Light Scattering (DLS), was between 90-110 nm. In this study, different approaches were explored to create radiolabeled NPs that are stable in solution. The NPs were functionalized with polycarboxylate or polyamine surface functional groups. Polycarboxylate functionalized NPs had a zeta potential of -35 mV and polyamine functionalized NPs had a zeta potential of +40 mV. The polycarboxylate functionalized NPs were chosen for in vivo biodistribution studies and hence were radiolabeled with (14)C, with a final activity of 0.097 nCi mg(-1) of NPs. In chronic studies, the biodistribution profile is tracked using low level radiolabeled proxies of the nanoparticles of interest. Conventionally, these radiolabeled proxies are chemically similar but not chemically identical to the non-radiolabeled NPs of interest. This study is novel as different approaches were explored to create radiolabeled NPs that are stable, possess a hydrodynamic radius of <100 nm and most importantly they exhibit an identical surface chemical functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and detection techniques. The radiolabeling approach described here is applicable to the synthesis of a large class of nanomaterials with multiple core and surface functionalities. This work combined with the biodistribution data suggests that the radiolabeling schemes carried out in this study have broad implications for use in pharmacokinetic studies for a variety of nanomaterials.
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Affiliation(s)
- Prakash D. Nallathamby
- Battelle Center for Fundamental and Applied Systems Toxicology, Battelle Memorial Institute, Columbus, OH 43201, USA
- Biological and Environmental Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Aerospace and Mechanical Engineering; Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Ninell P. Mortensen
- Biological and Environmental Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Heather A. Palko
- Battelle Center for Fundamental and Applied Systems Toxicology, Battelle Memorial Institute, Columbus, OH 43201, USA
- Biosciences and Biotechnology Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Mike Malfatti
- Biosciences and Biotechnology Division, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Catherine Smith
- Battelle Center for Fundamental and Applied Systems Toxicology, Battelle Memorial Institute, Columbus, OH 43201, USA
| | - James Sonnett
- Battelle Center for Fundamental and Applied Systems Toxicology, Battelle Memorial Institute, Columbus, OH 43201, USA
| | - Mitchel J. Doktycz
- Biological and Environmental Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Baohua Gu
- Biological and Environmental Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Ryan K. Roeder
- Department of Aerospace and Mechanical Engineering; Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Wei Wang
- Biological and Environmental Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Scott T. Retterer
- Biological and Environmental Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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14
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Devineni D, Murphy J, Wang SS, Stieltjes H, Rothenberg P, Scheers E, Mamidi RNVS. Absolute oral bioavailability and pharmacokinetics of canagliflozin: A microdose study in healthy participants. Clin Pharmacol Drug Dev 2014; 4:295-304. [PMID: 27136910 DOI: 10.1002/cpdd.162] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/25/2014] [Indexed: 12/17/2022]
Abstract
Absolute oral bioavailability of canagliflozin was assessed by simultaneous oral administration with intravenous [(14) C]-canagliflozin microdose infusion in nine healthy men. Pharmacokinetics of canagliflozin, [(14) C]-canagliflozin, and total radioactivity, and safety and tolerability were assessed at prespecified timepoints. On day 1, single-dose oral canagliflozin (300 mg) followed 105 minutes later by intravenous [(14) C]-canagliflozin (10 µg, 200 nCi) was administered. After oral administration, the mean (SD) Cmax of canagliflozin was 2504 (482) ng/mL at 1.5 hours, AUC∞ 17,375 (3555) ng.h/mL, and t1/2 11.6 (0.70) hours. After intravenous administration, the mean (SD) Cmax of unchanged [(14) C]-canagliflozin was 17,605 (6901) ng/mL, AUC∞ 27,100 (10,778) ng.h/mL, Vdss 83.5 (29.2) L, Vdz 119 (41.6) L, and CL 12.2 (3.79) L/h. Unchanged [(14) C]-canagliflozin and metabolites accounted for about 57% and 43% of the plasma total [(14) C] radioactivity AUC∞ , respectively. For total [(14) C] radioactivity, the mean (SD) Cmax was 15,981 (2721) ng-eq/mL, and AUC∞ 53,755 (15,587) ng-eq.h/mL. Renal (34.5% in urine) and biliary (34.1% in feces) excretions were the major elimination pathways for total [(14) C] radioactivity. The absolute oral bioavailability of canagliflozin was 65% (90% confidence interval: 55.41; 76.07). Overall, oral canagliflozin 300 mg coadministered with intravenous [(14) C]-canagliflozin (10 µg) was generally well-tolerated in healthy men, with no treatment-emergent adverse events.
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Affiliation(s)
| | - Joseph Murphy
- Janssen Research & Development, LLC, Raritan, NJ, USA
| | | | - Hans Stieltjes
- Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | | | - Ellen Scheers
- Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
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15
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Dingley KH, Ubick EA, Vogel JS, Ognibene TJ, Malfatti MA, Kulp K, Haack KW. DNA isolation and sample preparation for quantification of adduct levels by accelerator mass spectrometry. Methods Mol Biol 2014; 1105:147-57. [PMID: 24623226 DOI: 10.1007/978-1-62703-739-6_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Accelerator mass spectrometry (AMS) is a highly sensitive technique used for the quantification of adducts following exposure to carbon-14- or tritium-labeled chemicals, with detection limits in the range of one adduct per 10(11)-10(12) nucleotides. The protocol described in this chapter provides an optimal method for isolating and preparing DNA samples to measure isotope-labeled DNA adducts by AMS. When preparing samples, special precautions must be taken to avoid cross-contamination of isotope among samples and produce a sample that is compatible with AMS. The DNA isolation method described is based upon digestion of tissue with proteinase K, followed by extraction of DNA using Qiagen isolation columns. The extracted DNA is precipitated with isopropanol, washed repeatedly with 70 % ethanol to remove salt, and then dissolved in water. DNA samples are then converted to graphite or titanium hydride and the isotope content measured by AMS to quantify adduct levels. This method has been used to reliably generate good yields of uncontaminated, pure DNA from animal and human tissues for analysis of adduct levels.
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Affiliation(s)
- Karen H Dingley
- Biology and Biotechnology Research Program, Center for Accelerator Mass Spectroscopy, Lawrence Livermore National Laboratory, Livermore, CA, 94551, USA,
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16
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Warren AD, Gaylord ST, Ngan KC, Dumont Milutinovic M, Kwong GA, Bhatia SN, Walt DR. Disease detection by ultrasensitive quantification of microdosed synthetic urinary biomarkers. J Am Chem Soc 2014; 136:13709-14. [PMID: 25198059 PMCID: PMC4183649 DOI: 10.1021/ja505676h] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The delivery of exogenous agents can enable noninvasive disease monitoring, but existing low-dose approaches require complex infrastructure. In this paper, we describe a microdose-scale injectable formulation of nanoparticles that interrogate the activity of thrombin, a key regulator of clotting, and produce urinary reporters of disease state. We establish a customized single molecule detection assay that enables urinary discrimination of thromboembolic disease in mice using doses of the nanoparticulate diagnostic agents that fall under regulatory guidelines for "microdosing."
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Affiliation(s)
- Andrew D Warren
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Building 76-453, Cambridge, Massachusetts 02139, United States
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17
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Abstract
Use of the highly toxic and easily prepared rodenticide tetramethylenedisulfotetramine (TETS) was banned after thousands of accidental or intentional human poisonings, but it is of continued concern as a chemical threat agent. TETS is a noncompetitive blocker of the GABA type A receptor (GABAAR), but its molecular interaction has not been directly established for lack of a suitable radioligand to localize the binding site. We synthesized [(14)C]TETS (14 mCi/mmol, radiochemical purity >99%) by reacting sulfamide with H(14)CHO and s-trioxane then completion of the sequential cyclization with excess HCHO. The outstanding radiocarbon sensitivity of accelerator mass spectrometry (AMS) allowed the use of [(14)C]TETS in neuroreceptor binding studies with rat brain membranes in comparison with the standard GABAAR radioligand 4'-ethynyl-4-n-[(3)H]propylbicycloorthobenzoate ([(3)H]EBOB) (46 Ci/mmol), illustrating the use of AMS for characterizing the binding sites of high-affinity (14)C radioligands. Fourteen noncompetitive antagonists of widely diverse chemotypes assayed at 1 or 10 µM inhibited [(14)C]TETS and [(3)H]EBOB binding to a similar extent (r(2) = 0.71). Molecular dynamics simulations of these 14 toxicants in the pore region of the α1β2γ2 GABAAR predict unique and significant polar interactions for TETS with α1T1' and γ2S2', which are not observed for EBOB or the GABAergic insecticides. Several GABAAR modulators similarly inhibited [(14)C]TETS and [(3)H]EBOB binding, including midazolam, flurazepam, avermectin Ba1, baclofen, isoguvacine, and propofol, at 1 or 10 μM, providing an in vitro system for recognizing candidate antidotes.
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18
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Mass balance and metabolism of the antimalarial pyronaridine in healthy volunteers. Eur J Drug Metab Pharmacokinet 2014; 40:75-86. [DOI: 10.1007/s13318-014-0182-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 02/21/2014] [Indexed: 11/26/2022]
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19
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Etminan N, Buchholz BA, Dreier R, Bruckner P, Torner JC, Steiger HJ, Hänggi D, Macdonald RL. Cerebral aneurysms: formation, progression, and developmental chronology. Transl Stroke Res 2013; 5:167-73. [PMID: 24323717 DOI: 10.1007/s12975-013-0294-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 10/06/2013] [Accepted: 10/08/2013] [Indexed: 02/08/2023]
Abstract
The prevalence of unruptured intracranial aneurysms (UIAs) in the general population is up to 3%. Existing epidemiological data suggests that only a small fraction of UIAs progress towards rupture over the lifetime of an individual, but the surrogates for subsequent rupture and the natural history of UIAs are discussed very controversially at present. In case of rupture of an UIA, the case fatality is up to 50%, which therefore continues to stimulate interest in the pathogenesis of cerebral aneurysm formation and progression. Actual data on the chronological development of cerebral aneurysm has been especially difficult to obtain and, until recently, the existing knowledge in this respect is mainly derived from animal or mathematical models or short-term observational studies. Here, we review the current data on cerebral aneurysm formation and progression as well as a novel approach to investigate the developmental chronology of cerebral aneurysms.
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Affiliation(s)
- Nima Etminan
- Department of Neurosurgery, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225, Dusseldorf, Germany,
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20
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Chung IM, Kim SH. Biological and biomedical (14)C-accelerator mass spectrometry and graphitization of carbonaceous samples. Analyst 2013; 138:3347-55. [PMID: 23626987 DOI: 10.1039/c3an00077j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accelerator mass spectrometry (AMS) is the ultimate technique for measuring rare isotopes in small samples. Biological and biomedical applications of (14)C-AMS (bio-(14)C-AMS) commenced in the early 1990s and are now widely used in many research fields including pharmacology, toxicology, food, and nutrition. For accurate, precise, and reproducible bio-(14)C-AMS analysis, the graphitization step in sample preparation is the most critical step. So, various sample preparation methods for a process called graphitization have been reported for specific applications. Catalytic graphitization using either a flame-sealed borosilicate tube or a septa-sealed vial is a popular sample preparation method for bio-(14)C-AMS. In this review, we introduce the AMS system, especially for bio-(14)C-AMS. In addition, we also review the graphitization method for bio-(14)C-AMS to promote further understanding and improvement of sample preparation for this technique. Examples of catalytic graphitization methods over the past two decades are described.
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Affiliation(s)
- Ill-Min Chung
- Department of Applied Bioscience, College of Life and Environmental Science, Konkuk University, Seoul 143-701, Republic of Korea
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21
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Abstract
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 this article refers to studies using a negligible amount (nanocuries) of (14)C as tracer, and AMS as a quantitative technique. The technology is by no means a panacea for the deficiency in pediatric clinical research; however, it lessens the challenges and provides the most quantitative tool for pediatric pharmacology studies.
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22
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Neuwirth C, Mosesso P, Pepe G, Fiore M, Malfatti M, Turteltaub K, Dekant W, Mally A. Furan carcinogenicity: DNA binding and genotoxicity of furan in rats in vivo. Mol Nutr Food Res 2012; 56:1363-74. [PMID: 22865590 DOI: 10.1002/mnfr.201200226] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 05/21/2012] [Accepted: 06/05/2012] [Indexed: 11/09/2022]
Abstract
SCOPE Furan is a potent hepatotoxicant and liver carcinogen in rodents. However, short-term tests for genotoxicity of furan are inconclusive. The aim of this study was to assess the potential of furan to covalently bind to DNA, and to assess furan genotoxicity in rats in vivo. MATERIALS AND METHODS Accelerator mass spectrometry was used to determine the (14) C-content in DNA following administration of [3,4-(14) C]-furan (0.1 and 2.0 mg/kg bw) to F344 rats. DNA damage, micronuclei, chromosomal aberrations, and sister chromatid exchanges were analyzed in F344 rats treated with furan for up to 28 days. CONCLUSION The (14) C-content in liver DNA was significantly increased in a dose-dependent manner, with mean concentrations of 7.9 ± 3.5 amol (14) C/μg DNA and 153.3 ± 100.2 amol (14) C/μg DNA, corresponding to 16.5 ± 7.4 and 325.2 ± 212.7 adducts/10(9) nucleotides at 0.1 and 2.0 mg/kg bw, respectively. There was no evidence for genotoxicity of furan in peripheral blood and bone marrow cells. However, a dose-related increase in the incidence of chromosomal aberrations in rat splenocytes and some indication of DNA damage in liver were observed. Collectively, results from this study indicate that furan may operate-at least in part-by a genotoxic mode of action.
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Affiliation(s)
- Carolin Neuwirth
- Department of Toxicology, University of Würzburg, Würzburg, Germany
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23
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Schebb NH, Buchholz BA, Hammock BD, Rice RH. Metabolism of the antibacterial triclocarban by human epidermal keratinocytes to yield protein adducts. J Biochem Mol Toxicol 2012; 26:230-4. [PMID: 22711420 PMCID: PMC3522462 DOI: 10.1002/jbt.21411] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies of triclocarban suggest that its biotransformation could yield reactive metabolites that form protein adducts. Since the skin is the major route of triclocarban exposure, present work examined this possibility in cultured human keratinocytes. The results provide evidence for considerable biotransformation and protein adduct formation when cytochrome P450 activity is induced in the cells by 2,3,7,8-tetrachlorodibenzo-p-dioxin, a model Ah receptor ligand. Since detecting low adduct levels in cells and tissues is difficult, we utilized the novel approach of accelerator mass spectrometry for this purpose. Exploiting the sensitivity of the method, we demonstrated that a substantial portion of triclocarban forms adducts with keratinocyte protein under the P450 inducing conditions employed.
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Affiliation(s)
- Nils Helge Schebb
- Institute of Food Toxicology and Chemical Analysis, University of Veterinary Medicine Hannover, Germany
| | - Bruce A. Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - Bruce D. Hammock
- Department of Entomology and Cancer Center, University of California, Davis, CA
| | - Robert H. Rice
- Department of Environmental Toxicology, University of California, Davis, CA
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24
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Food authenticity using natural carbon isotopes (12C, 13C, 14C) in grass-fed and grain-fed beef. Food Sci Biotechnol 2012. [DOI: 10.1007/s10068-012-0040-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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25
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Gao L, Li J, Kasserra C, Song Q, Arjomand A, Hesk D, Chowdhury SK. Precision and Accuracy in the Quantitative Analysis of Biological Samples by Accelerator Mass Spectrometry: Application in Microdose Absolute Bioavailability Studies. Anal Chem 2011; 83:5607-16. [DOI: 10.1021/ac2006284] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - Qi Song
- Accium BioSciences, Inc., Seattle, Washington 98122, United States
| | - Ali Arjomand
- Accium BioSciences, Inc., Seattle, Washington 98122, United States
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26
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Dueker SR, Vuong LT, Lohstroh PN, Giacomo JA, Vogel JS. Quantifying exploratory low dose compounds in humans with AMS. Adv Drug Deliv Rev 2011; 63:518-31. [PMID: 21047543 PMCID: PMC3062634 DOI: 10.1016/j.addr.2010.10.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 10/08/2010] [Accepted: 10/18/2010] [Indexed: 11/20/2022]
Abstract
Accelerator Mass Spectrometry is an established technology whose essentiality extends beyond simply a better detector for radiolabeled molecules. Attomole sensitivity reduces radioisotope exposures in clinical subjects to the point that no population need be excluded from clinical study. Insights in human physiochemistry are enabled by the quantitative recovery of simplified AMS processes that provide biological concentrations of all labeled metabolites and total compound related material at non-saturating levels. In this paper, we review some of the exploratory applications of AMS (14)C in toxicological, nutritional, and pharmacological research. This body of research addresses the human physiochemistry of important compounds in their own right, but also serves as examples of the analytical methods and clinical practices that are available for studying low dose physiochemistry of candidate therapeutic compounds, helping to broaden the knowledge base of AMS application in pharmaceutical research.
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27
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Kim SH, Chuang JC, Kelly PB, Clifford AJ. Carbon isotopes profiles of human whole blood, plasma, red blood cells, urine and feces for biological/biomedical 14C-accelerator mass spectrometry applications. Anal Chem 2011; 83:3312-8. [PMID: 21452856 DOI: 10.1021/ac103038s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Radiocarbon ((14)C) is an ideal tracer for in vivo human ADME (absorption, distribution, metabolism, elimination) and PBPK (physiological-based pharmacokinetic) studies. Living plants peferentially incorporate atmospheric (14)CO(2) versus (13)CO(2) versus (12)CO(2), which result in unique signature. Furthermore, plants and the food chains they support also have unique carbon isotope signatures. Humans, at the top of the food chain, consequently acquire isotopic concentrations in the tissues and body fluids depending on their dietary habits. In preparation of ADME and PBPK studies, 12 healthy subjects were recruited. The human baseline (specific to each individual and their diet) total carbon (TC) and carbon isotope (13)C (δ(13)C) and (14)C (F(m)) were quantified in whole blood (WB), plasma, washed red blood cell (RBC), urine, and feces. TC (mg of C/100 μL) in WB, plasma, RBC, urine, and feces were 11.0, 4.37, 7.57, 0.53, and 1.90, respectively. TC in WB, RBC, and feces was higher in men over women, P < 0.05. Mean δ(13)C were ranked low to high as follows: feces < WB = plasma = RBC = urine, P < 0.0001. δ(13)C was not affected by gender. Our analytic method shifted δ(13)C by only ±1.0 ‰ ensuring our F(m) measurements were accurate and precise. Mean F(m) were ranked low to high as follows: plasma = urine < WB = RBC = feces, P < 0.05. F(m) in feces was higher for men over women, P < 0.05. Only in WB, (14)C levels (F(m)) and TC were correlated with one another (r = 0.746, P < 0.01). Considering the lag time to incorporate atmospheric (14)C into plant foods (vegetarian) and or then into animal foods (nonvegetarian), the measured F(m) of WB in our population (recruited April 2009) was 1.0468 ± 0.0022 (mean ± SD), and the F(m) of WB matched the (extrapolated) atmospheric F(m) of 1.0477 in 2008. This study is important in presenting a procedure to determine a baseline for a study group for human ADME and PBPK studies using (14)C as a tracer.
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Affiliation(s)
- Seung-Hyun Kim
- Department of Nutrition, University of California Davis, 95616, USA
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Accelerator mass spectrometry-enabled studies: current status and future prospects. Bioanalysis 2011; 2:519-41. [PMID: 20440378 DOI: 10.4155/bio.09.188] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Accelerator mass spectrometry is a detection platform with exceptional sensitivity compared with other bioanalytical platforms. Accelerator mass spectrometry (AMS) is widely used in archeology for radiocarbon dating applications. Early exploration of the biological and pharmaceutical applications of AMS began in the early 1990s. AMS has since demonstrated unique problem-solving ability in nutrition science, toxicology and pharmacology. AMS has also enabled the development of new applications, such as Phase 0 microdosing. Recent development of AMS-enabled applications has transformed this novelty research instrument to a valuable tool within the pharmaceutical industry. Although there is now greater awareness of AMS technology, recognition and appreciation of the range of AMS-enabled applications is still lacking, including study-design strategies. This review aims to provide further insight into the wide range of AMS-enabled applications. Examples of studies conducted over the past two decades will be presented, as well as prospects for the future of AMS.
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Analytical validation of accelerator mass spectrometry for pharmaceutical development. Bioanalysis 2011; 2:469-85. [PMID: 21083256 DOI: 10.4155/bio.10.14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of (14)C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the (14)C label), stable across samples storage conditions for at least 1 year, linear over four orders of magnitude with an analytical range from 0.1 Modern to at least 2000 Modern (instrument specific). Furthermore, accuracy was excellent (between 1 and 3%), while precision expressed as coefficient of variation was between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of (14)C, respectively (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with (14)C corresponds to 30 fg equivalents. Accelerator mass spectrometry provides a sensitive, accurate and precise method of measuring drug compounds in biological matrices.
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AMS method validation for quantitation in pharmacokinetic studies with concomitant extravascular and intravenous administration. Bioanalysis 2011; 3:393-405. [DOI: 10.4155/bio.11.5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A technique has emerged in the past few years that has enabled a drug’s intravenous pharmacokinetics to be readily obtained in humans without having to conduct extensive toxicology studies by this route of administration or expend protracted effort in formulation. The technique involves the intravenous administration of a low dose of 14C-labelled drug (termed a tracer dose) concomitantly with a non-labelled extravascular dose given at therapeutically levels. Plasma samples collected over time are analysed to determine the total parent drug concentration by LC–MS (which essentially measures that arising from the oral dose) and by LC followed by accelerator mass spectrometry (AMS) to determine the 14C-drug concentration (i.e., that arising from the intravenous dose). There are currently no published accounts of how the principles of bioanalytical validation might be applied to intravenous studies using AMS as an analytical technique. The authors describe the primary elements of AMS when used with LC seperation and how this off-line technique differs from LC–MS. They then discuss how the principles of bioanalytical validation might be applied to determine selectivity, accuracy, precision and stability of methods involving LC followed by AMS analysis.
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Stewart BJ, Navid A, Turteltaub KW, Bench G. Yeast dynamic metabolic flux measurement in nutrient-rich media by HPLC and accelerator mass spectrometry. Anal Chem 2010; 82:9812-7. [PMID: 21062031 DOI: 10.1021/ac102065f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabolic flux, the flow of metabolites through networks of enzymes, represents the dynamic productive output of cells. Improved understanding of intracellular metabolic fluxes will enable targeted manipulation of metabolic pathways of medical and industrial importance to a greater degree than is currently possible. Flux balance analysis (FBA) is a constraint-based approach to modeling metabolic fluxes, but its utility is limited by a lack of experimental measurements. Incorporation of experimentally measured fluxes as system constraints will significantly improve the overall accuracy of FBA. We applied a novel, two-tiered approach in the yeast Saccharomyces cerevisiae to measure nutrient consumption rates (extracellular fluxes) and a targeted intracellular flux using a (14)C-labeled precursor with HPLC separation and flux quantitation by accelerator mass spectrometry (AMS). The use of AMS to trace the intracellular fate of (14)C-glutamine allowed the calculation of intracellular metabolic flux through this pathway, with glutathione as the metabolic end point. Measured flux values provided global constraints for the yeast FBA model which reduced model uncertainty by more than 20%, proving the importance of additional constraints in improving the accuracy of model predictions and demonstrating the use of AMS to measure intracellular metabolic fluxes. Our results highlight the need to use intracellular fluxes to constrain the models. We show that inclusion of just one such measurement alone can reduce the average variability of model predicted fluxes by 10%.
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Affiliation(s)
- Benjamin J Stewart
- Lawrence Livermore National Laboratory, Center for Accelerator Mass Spectrometry, 7000 East Avenue P.O. Box 808, L-397 Livermore, California 94551, USA.
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Aklamati EK, Mulenga M, Dueker SR, Buchholz BA, Peerson JM, Kafwembe E, Brown KH, Haskell MJ. Accelerator mass spectrometry can be used to assess vitamin A metabolism quantitatively in boys in a community setting. J Nutr 2010; 140:1588-94. [PMID: 20660280 PMCID: PMC3139233 DOI: 10.3945/jn.110.125500] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A survey indicated that high-dose vitamin A (HD-VA) supplements had no apparent effect on vitamin A (VA) status, assessed by serum retinol concentrations, of Zambian children lt 5 y of age. To explore possible reasons for the lack of response, we quantified absorption, retention, and urinary elimination of either a single HD-VA supplement (209.8 micromol; 60 mg) or a smaller dose of stable isotope (SI)-labeled VA (17.5 micromol; 5 mg), which was used to estimate VA pool size, in 3- to 4-y-old Zambian boys (n = 4 for each VA dose). A tracer dose of [(14)C(2)]-labeled VA (0.925 kBq; 25 nCi) was coadministered with the HD-VA supplement or SI-labeled VA, and 24-h stool and urine samples were collected for 3 and 7 consecutive days, respectively, and 24-h urine samples at 4 later time points. Accelerator MS was used to quantify (14)C in stool and urine. Estimates of absorption, retention, and the urinary elimination rate (UER) were 83.8 +/- 7.1%, 76.3 +/- 6.7%, and 1.9 +/- 0.6%/d, respectively, for the HD-VA supplement and 76.5 +/- 9.5%, 71.1 +/- 9.4%, and 1.8 +/- 1.2%/d, respectively, for the SI-labeled VA. Mean estimates of absorption, retention, and the UER did not differ by size of the VA dose administered. Estimated absorption and retention were negatively associated with reported fever (r = minus 0.83; P = 0.011). The HD-VA supplement and SI-labeled VA were adequately absorbed, retained, and utilized in apparently healthy Zambian preschool-age boys; absorption and retention may be affected by recent fever.
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Affiliation(s)
- Emmanuel K. Aklamati
- Program in International and Community Nutrition and Department of Nutrition, University of California, Davis, CA 95616
| | - Modest Mulenga
- Tropical Diseases Research Center, Ndola Central Hospital, Ndola 50100, Zambia
| | | | - Bruce A. Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratories, Livermore, CA 94551
| | - Janet M. Peerson
- Program in International and Community Nutrition and Department of Nutrition, University of California, Davis, CA 95616
| | - Emmanuel Kafwembe
- Tropical Diseases Research Center, Ndola Central Hospital, Ndola 50100, Zambia
| | - Kenneth H. Brown
- Program in International and Community Nutrition and Department of Nutrition, University of California, Davis, CA 95616
| | - Marjorie J. Haskell
- Program in International and Community Nutrition and Department of Nutrition, University of California, Davis, CA 95616,To whom correspondence should be addressed. E-mail:
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Kim SH, Kelly PB, Clifford AJ. Calculating radiation exposures during use of (14)C-labeled nutrients, food components, and biopharmaceuticals to quantify metabolic behavior in humans. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:4632-7. [PMID: 20349979 PMCID: PMC2857889 DOI: 10.1021/jf100113c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/12/2010] [Accepted: 03/16/2010] [Indexed: 05/29/2023]
Abstract
(14)C has long been used as a tracer for quantifying the in vivo human metabolism of food components, biopharmaceuticals, and nutrients. Minute amounts (< or =1 x 10 (-18) mol) of (14)C can be measured with high-throughput (14)C-accelerator mass spectrometry (HT (14)C-AMS) in isolated chemical extracts of biological, biomedical, and environmental samples. Availability of in vivo human data sets using a (14)C tracer would enable current concepts of the metabolic behavior of food components, biopharmaceuticals, or nutrients to be organized into models suitable for quantitative hypothesis testing and determination of metabolic parameters. In vivo models are important for specification of intake levels for food components, biopharmaceuticals, and nutrients. Accurate estimation of the radiation exposure from ingested (14)C is an essential component of the experimental design. Therefore, this paper illustrates the calculation involved in determining the radiation exposure from a minute dose of orally administered (14)C-beta-carotene, (14)C-alpha-tocopherol, (14)C-lutein, and (14)C-folic acid from four prior experiments. The administered doses ranged from 36 to 100 nCi, and radiation exposure ranged from 0.12 to 5.2 microSv to whole body and from 0.2 to 3.4 microSv to liver with consideration of tissue weighting factor and fractional nutrient. In comparison, radiation exposure experienced during a 4 h airline flight across the United States at 37000 ft was 20 microSv.
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Kim SH, Kelly PB, Ortalan V, Browning ND, Clifford AJ. Quality of graphite target for biological/biomedical/environmental applications of 14C-accelerator mass spectrometry. Anal Chem 2010; 82:2243-52. [PMID: 20163100 PMCID: PMC2837469 DOI: 10.1021/ac9020769] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 02/03/2010] [Indexed: 11/28/2022]
Abstract
Catalytic graphitization for (14)C-accelerator mass spectrometry ((14)C-AMS) produced various forms of elemental carbon. Our high-throughput Zn reduction method (C/Fe = 1:5, 500 degrees C, 3 h) produced the AMS target of graphite-coated iron powder (GCIP), a mix of nongraphitic carbon and Fe(3)C. Crystallinity of the AMS targets of GCIP (nongraphitic carbon) was increased to turbostratic carbon by raising the C/Fe ratio from 1:5 to 1:1 and the graphitization temperature from 500 to 585 degrees C. The AMS target of GCIP containing turbostratic carbon had a large isotopic fractionation and a low AMS ion current. The AMS target of GCIP containing turbostratic carbon also yielded less accurate/precise (14)C-AMS measurements because of the lower graphitization yield and lower thermal conductivity that were caused by the higher C/Fe ratio of 1:1. On the other hand, the AMS target of GCIP containing nongraphitic carbon had higher graphitization yield and better thermal conductivity over the AMS target of GCIP containing turbostratic carbon due to optimal surface area provided by the iron powder. Finally, graphitization yield and thermal conductivity were stronger determinants (over graphite crystallinity) for accurate/precise/high-throughput biological, biomedical, and environmental (14)C-AMS applications such as absorption, distribution, metabolism, elimination (ADME), and physiologically based pharmacokinetics (PBPK) of nutrients, drugs, phytochemicals, and environmental chemicals.
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Affiliation(s)
| | | | | | | | - Andrew J. Clifford
- To whom correspondence should be addressed. E-mail: . Tel: 530-752-3376. Fax: 530-752-8966
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Early human ADME using microdoses and microtracers: bioanalytical considerations. Bioanalysis 2010; 2:441-54. [DOI: 10.4155/bio.10.8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Quantitative assessment of metabolites of drug candidates in early-phase clinical development presents an analytical challenge when methods, standards and assays are not yet available. Radioisotopic labeling, principally with radiocarbon (14C), is the preferred method for discovering and quantifying the absolute yields of metabolites in the absence of reference material or a priori knowledge of the human metabolism. However, the detection of 14C is inefficient by decay counting methods and, as a result, high radiological human 14C-doses had been needed to assure sensitive detection of metabolites over time. High radiological doses and the associated costs have been a major obstacle to the routine (and early) use of 14C despite the recognized advantages of a 14C-tracer for quantifying drug metabolism and disposition. Accelerator mass spectrometry eliminates this long-standing problem by reducing radioactivity levels while delivering matrix-independent quantitation to attomole levels of sensitivity in small samples or fractionated isolates. Accelerator mass spectrometry and trace 14C-labeled drugs are now used to obtain early insights into the human metabolism of a drug candidate in ways that were not previously practical. With this article we describe some of our empirically based approaches for regualted bioanalysis and offer perspectives on current applications and opportunities for the future.
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Accelerator mass spectrometry best practices for accuracy and precision in bioanalytical 14C measurements. Bioanalysis 2010; 2:455-68. [DOI: 10.4155/bio.10.13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Accelerator mass spectrometers have an energy acceleration and charge exchange between mass definition stages to destroy molecular isobars and allow single ion counting of long-lived isotopes such as 14C (t½=5370 years.). ‘Low’ voltage accelerations to 200 kV allow laboratory-sized accelerator mass spectrometers instruments for bioanalytical quantitation of 14C to 2–3% precision and accuracy in isolated biochemical fractions. After demonstrating this accuracy and precision for our new accelerator mass spectrometer, we discuss the critical aspects of maintaining quantitative accuracy from the defined biological fraction to the accelerator mass spectrometry quantitation. These aspects include sufficient sample mass for routine rapid sample preparation, isotope dilution to assure this mass, isolation of the carbon from other sample combustion gasses and use of high-efficiency biochemical separations. This review seeks to address a bioanalytical audience, who should know that high accuracy data of physiochemical processes within living human subjects are available, as long as a 14C quantitation can be made indicative of the physiochemistry of interest.
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Microdosing: a valuable tool for accelerating drug development and the role of bioanalytical methods in meeting the challenge. Bioanalysis 2009; 1:1293-305. [DOI: 10.4155/bio.09.107] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The concept of specifically determining the clinical pharmacokinetics of a compound using a very low nonpharmacologically active dose (microdose) with an abridged safety and chemistry, manufacturing and control package is relatively new. It is not without its controversy and it is still a subject of discussion. Here, the rationale and application of this approach are examined, together with the regulatory and bioanalytical framework. There are two bioanalytical methods commonly used for human microdosing studies: LC–MS/MS and accelerator MS (AMS). Each method has advantages and disadvantages with the choice of instrumentation being closely tied to the primary objective(s) of the study. If a rapid decision is required on the appropriateness of a pharmacokinetic profile or if a choice is needed from a series of compounds, especially before radiolabeled material is available, LC–MS/MS may be preferable. However, if extreme sensitivity is required, data are required on all drug-related material and metabolites, or a simultaneous intravenous microdose is used to determine absolute bioavailability (sometimes referred to as microtracing), AMS becomes the analytical method of choice. Examples are provided of microdosing studies utilizing both of these bioanalytical techniques. It is emphasized that microdosing is only one tool in the drug developer’s tool box and it should be used in the context of all available data. However, when used appropriately, microdosing is a valuable tool, bridging between lead optimization and early clinical development.
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Hah SS, Henderson PT, Turteltaub KW. Recent advances in biomedical applications of accelerator mass spectrometry. J Biomed Sci 2009; 16:54. [PMID: 19534792 PMCID: PMC2712465 DOI: 10.1186/1423-0127-16-54] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Accepted: 06/17/2009] [Indexed: 11/13/2022] Open
Abstract
The use of radioisotopes has a long history in biomedical science, and the technique of accelerator mass spectrometry (AMS), an extremely sensitive nuclear physics technique for detection of very low-abundant, stable and long-lived isotopes, has now revolutionized high-sensitivity isotope detection in biomedical research, because it allows the direct determination of the amount of isotope in a sample rather than measuring its decay, and thus the quantitative analysis of the fate of the radiolabeled probes under the given conditions. Since AMS was first used in the early 90's for the analysis of biological samples containing enriched 14C for toxicology and cancer research, the biomedical applications of AMS to date range from in vitro to in vivo studies, including the studies of 1) toxicant and drug metabolism, 2) neuroscience, 3) pharmacokinetics, and 4) nutrition and metabolism of endogenous molecules such as vitamins. In addition, a new drug development concept that relies on the ultrasensitivity of AMS, known as human microdosing, is being used to obtain early human metabolism information of candidate drugs. These various aspects of AMS are reviewed and a perspective on future applications of AMS to biomedical research is provided.
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Affiliation(s)
- Sang Soo Hah
- Department of Chemistry and Research Institute for Basic Sciences, Kyung Hee University 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-701, Korea.
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Zhu M, Zhang D, Zhang H, Shyu WC. Integrated strategies for assessment of metabolite exposure in humans during drug development: analytical challenges and clinical development considerations. Biopharm Drug Dispos 2009; 30:163-84. [DOI: 10.1002/bdd.659] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Salehpour M, Forsgard N, Possnert G. FemtoMolar measurements using accelerator mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:557-563. [PMID: 19177507 DOI: 10.1002/rcm.3903] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Accelerator mass spectrometry (AMS) is an ultra-sensitive analytical method suitable for the detection of sub-nM concentrations of labeled biological substances such as pharmaceutical drugs in body fluids. A limiting factor in extending the concentration measurements to the sub-pM range is the natural (14)C content in living tissues. This was circumvented by separating the labeled drug from the tissue matrix, using standard high-performance liquid chromatography (HPLC) procedures. As the separated total drug amount is in the few fg range, it is not possible to use a standard AMS sample preparation method, where mg sizes are required. We have utilized a sensitive carbon carrier method where a (14)C-deficient compound is added to the HPLC fractions and the composite sample is prepared and analyzed by AMS. Using 50 microL human blood plasma aliquots, we have demonstrated concentration measurements below 20 fM, containing sub-amol amounts of the labeled drug. The method has the immediate potential of operating in the sub-fM region.
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Affiliation(s)
- Mehran Salehpour
- Ion Physics, Angström Laboratory, Department of Engineering Sciences, Box 534, Uppsala University, SE-751 21 Uppsala, Sweden.
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Kim SH, Kelly PB, Clifford AJ. Biological/biomedical accelerator mass spectrometry targets. 1. optimizing the CO2 reduction step using zinc dust. Anal Chem 2008; 80:7651-60. [PMID: 18785761 PMCID: PMC2651631 DOI: 10.1021/ac801226g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biological and biomedical applications of accelerator mass spectrometry (AMS) use isotope ratio mass spectrometry to quantify minute amounts of long-lived radioisotopes such as 14C. AMS target preparation involves first the oxidation of carbon (in sample of interest) to CO2 and second the reduction of CO2 to filamentous, fluffy, fuzzy, or firm graphite-like substances that coat a −400-mesh spherical iron powder (−400MSIP) catalyst. Until now, the quality of AMS targets has been variable; consequently, they often failed to produce robust ion currents that are required for reliable, accurate, precise, and high-throughput AMS for biological/biomedical applications. Therefore, we described our optimized method for reduction of CO2 to high-quality uniform AMS targets whose morphology we visualized using scanning electron microscope pictures. Key features of our optimized method were to reduce CO2 (from a sample of interest that provided 1 mg of C) using 100 ± 1.3 mg of Zn dust, 5 ± 0.4 mg of −400MSIP, and a reduction temperature of 500 °C for 3 h. The thermodynamics of our optimized method were more favorable for production of graphite-coated iron powders (GCIP) than those of previous methods. All AMS targets from our optimized method were of 100% GCIP, the graphitization yield exceeded 90%, and δ13C was −17.9 ± 0.3‰. The GCIP reliably produced strong 12C− currents and accurate and precise Fm values. The observed Fm value for oxalic acid II NIST SRM deviated from its accepted Fm value of 1.3407 by only 0.0003 ± 0.0027 (mean ± SE, n = 32), limit of detection of 14C was 0.04 amol, and limit of quantification was 0.07 amol, and a skilled analyst can prepare as many as 270 AMS targets per day. More information on the physical (hardness/color), morphological (SEMs), and structural (FT-IR, Raman, XRD spectra) characteristics of our AMS targets that determine accurate, precise, and high-hroughput AMS measurement are in the companion paper.
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Affiliation(s)
- Seung-Hyun Kim
- Department of Nutrition, University of California Davis, One Shields Avenue, Davis, California 95616, USA
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Kim SH, Kelly PB, Clifford AJ. Biological/biomedical accelerator mass spectrometry targets. 2. Physical, morphological, and structural characteristics. Anal Chem 2008; 80:7661-9. [PMID: 18785762 PMCID: PMC2651734 DOI: 10.1021/ac801228t] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The number of biological/biomedical applications that require AMS to achieve their goals is increasing, and so is the need for a better understanding of the physical, morphological, and structural traits of high quality of AMS targets. The metrics of quality included color, hardness/texture, and appearance (photo and SEM), along with FT-IR, Raman, and powder X-ray diffraction spectra that correlate positively with reliable and intense ion currents and accuracy, precision, and sensitivity of fraction modern ( F m). Our previous method produced AMS targets of gray-colored iron-carbon materials (ICM) 20% of the time and of graphite-coated iron (GCI) 80% of the time. The ICM was hard, its FT-IR spectra lacked the sp (2) bond, its Raman spectra had no detectable G' band at 2700 cm (-1), and it had more iron carbide (Fe 3C) crystal than nanocrystalline graphite or graphitizable carbon (g-C). ICM produced low and variable ion current whereas the opposite was true for the graphitic GCI. Our optimized method produced AMS targets of graphite-coated iron powder (GCIP) 100% of the time. The GCIP shared some of the same properties as GCI in that both were black in color, both produced robust ion current consistently, their FT-IR spectra had the sp (2) bond, their Raman spectra had matching D, G, G', D +G, and D '' bands, and their XRD spectra showed matching crystal size. GCIP was a powder that was easy to tamp into AMS target holders that also facilitated high throughput. We concluded that AMS targets of GCIP were a mix of graphitizable carbon and Fe 3C crystal, because none of their spectra, FT-IR, Raman, or XRD, matched exactly those of the graphite standard. Nevertheless, AMS targets of GCIP consistently produced the strong, reliable, and reproducible ion currents for high-throughput AMS analysis (270 targets per skilled analyst/day) along with accurate and precise F m values.
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Affiliation(s)
- Seung-Hyun Kim
- Department of Nutrition, University of California Davis, One Shields Avenue, Davis, California 95616, USA
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Lappin G, Simpson M, Shishikura Y, Garner C. High-performance liquid chromatography accelerator mass spectrometry: Correcting for losses during analysis by internal standardization. Anal Biochem 2008; 378:93-5. [DOI: 10.1016/j.ab.2008.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 03/17/2008] [Accepted: 03/19/2008] [Indexed: 11/26/2022]
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Lockley WJS. Tritium chemistry: history, current status and future developments; a brief review. J Labelled Comp Radiopharm 2007. [DOI: 10.1002/jlcr.1232] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chang MS, Ji Q, Zhang J, El-Shourbagy TA. Historical review of sample preparation for chromatographic bioanalysis: pros and cons. Drug Dev Res 2007. [DOI: 10.1002/ddr.20173] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abstract
Accelerator mass spectrometry (AMS) counts individual rare, usually radio-, isotopes such as radiocarbon at high efficiency and specificity in milligram-sized samples. AMS traces very low chemical doses (micrograms) and radiative doses (100 Bq) of isotope-labeled compounds in animal models and directly in humans for pharmaceutical, nutritional, or toxicological research. Absorption, metabolism, distribution, binding, and elimination are all quantifiable with high precision after appropriate sample definition.
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Affiliation(s)
- John S Vogel
- Lawrence Livermore National Laboratory, University of California, Livermore, CA 94551, USA.
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