A gas chromatography-mass spectrometry (GC-MS) method for the simultaneous measurement of isotopic enrichment and concentration of guanidinoacetate (GAA) and creatine in plasma sample for kinetic studies is reported. The method, based on preparation of the bis(trifluoromethyl)pyrimidine methyl ester derivatives of GAA and creatine, is robust and sensitive. The lowest measurable m(1) and m(3) enrichment for GAA and creatine, respectively, was 0.3%. The calibration curves for measurements of concentration were linear over ranges of 0.5 to 250microM GAA and 2 to 500microM for creatine. The method was reliable for inter- and intraassay precision, accuracy, and linearity. The technique was applied in a healthy adult to determine the in vivo fractional synthesis rate of creatine using primed-constant rate infusion of [1-(13)C]glycine. It was found that isotopic enrichment of GAA reached a plateau by 30min of infusion of [1-(13)C]glycine, indicating either a small pool size or a rapid turnover rate (or both) of GAA. In contrast, the tracer appearance in creatine was slow (slope=0.00097), suggesting a large pool size and a slow rate of synthesis of creatine. This method can be used to estimate the rate of synthesis of creatine in vivo in human and animal studies.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3496933 | PMC |
| http://dx.doi.org/10.1016/j.ab.2009.07.037 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
High-precision Cu isotopic analysis of human dietary Cu sources via multi-collector ICP-mass spectrometry.
Food Chem
December 2024
Atomic and Mass Spectrometry - A&MS Research Unit, Department of Chemistry, Ghent University, 9000 Ghent, Belgium. Electronic address:
The disruption of Cu homeostasis is associated with the pathogenesis of many diseases and can result in alterations in Cu isotope fractionation. Changes in the Cu isotope ratio (Cu/Cu) of body fluids and tissues have been observed in liver disorders, cancers, and other diseases, displaying diagnostic/prognostic potential. However, it is not entirely clear whether certain physiological or lifestyle factors may also influence the bodily Cu isotopic composition, potentially obfuscating the signature of the pathology.
View Article and Find Full Text PDFFood web architecture and trophic interactions between organisms can be studied using ratios of naturally occurring stable isotopes of carbon (C/C) and nitrogen (N/N). Most studies, however, focused on free-living organisms, but recently, there has been growing interest in understanding trophic interactions of parasites. The crustacean ectoparasite is a well-studied parasite of freshwater teleost fish, which has low host specificity and a cosmopolitan distribution.
View Article and Find Full Text PDFTracking hydrothermal infiltration within light oil reservoirs using organic geochemical proxies in the Shunbei area of Tarim Basin in China.
Sci Rep
January 2025
Northwest Oilfield Company, SINOPEC, Ürümqi, 830011, China.
Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organic properties of crude oils. Understanding the interplay between hydrothermal fluids and crude oils would provide useful constraints for reconstructing hydrocarbon accumulation processes and predicting the distribution patterns of crude oils.
View Article and Find Full Text PDFFatty acid carbon isotopes as tracers of trophic structure and contaminant biomagnification in Arctic marine food webs.
Sci Total Environ
January 2025
Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada. Electronic address:
Mercury (Hg) and persistent organic pollutant (POP) accumulation among species and biomagnification through food webs is typically assessed using stable isotopes of nitrogen (δN) and carbon (δC) in bulk (whole) tissues. Yet, bulk isotopic approaches have limitations, notably from the potential overlap of isotope values from different dietary sources and from spatial variation in source (baseline) signals. Here, we explore the potential of fatty acid carbon isotopes (FA δC) to (1) evaluate the trophic structure of a marine food web, (2) distinguish feeding patterns among four marine mammal consumers, (3) trace contaminant biomagnification through a food web, and (4) explain interspecific variation in contaminants among high-trophic position predators.
View Article and Find Full Text PDFIsotopic variability of the invasive blue crab Callinectes sapidus in the Gulf of Cadiz: Impacts and implications for coastal ecosystem management.
J Environ Manage
January 2025
Department of Ecology and Coastal Management, Instituto de Ciencias Marinas de Andalucía (ICMAN-CSIC), Avda. República Saharaui, 2, Puerto Real, Cadiz, 11510, Spain; Associate Research Unit "Blue Growth", Spanish National Research Council (CSIC) - Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), Cadiz, Spain. Electronic address:
The variability in trophic position and carbon isotopic signatures can provide information about their dietary flexibility and its ability to adapt to changing environmental conditions. The impact of the invasive blue crab Callinectes sapidus was assessed by estimating its trophic position and isotopic niche using stable isotopes (δ³C, δ⁵N, δ³⁴S) across different invaded Atlantic coastal areas. This study, the first of its kind in the eastern Atlantic range, reveals the crab's omnivorous behavior with a wide trophic position (TP = 2-4), consistent with findings from its native range.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!