scholarly journals Automation of PRM-dependent D3-Leu tracer enrichment in HDL to study the metabolism of apoA-I, LCAT and other apolipoproteins

PROTEOMICS ◽  
2017 ◽  
Vol 17 (1-2) ◽  
pp. 1600085 ◽  
Author(s):  
Lang Ho Lee ◽  
Allison B. Andraski ◽  
Brett Pieper ◽  
Hideyuki Higashi ◽  
Frank M. Sacks ◽  
...  
Keyword(s):  
Tracer Enrichment

15N tracer enrichment in response to winter soil temperature manipulation differs between canopy trees and juveniles

Trees ◽  
2020 ◽  
Author(s):  
Hugh A. L. Henry ◽  
Juergen Kreyling ◽  
Gerhard Gebauer ◽  
Marcin Klisz ◽  
Robert Weigel
Keyword(s):  
Soil Temperature ◽  
15N Tracer ◽  
Canopy Trees ◽  
Temperature Manipulation ◽  
Tracer Enrichment

Relationship of plasma leucine and α-ketoisocaproate during a L-[1-13C]leucine infusion in man: A method for measuring human intracellular leucine tracer enrichment

Metabolism ◽  
1982 ◽  
Vol 31 (11) ◽  
pp. 1105-1112 ◽  
Author(s):  
D.E. Matthews ◽  
H.P. Schwarz ◽  
R.D. Yang ◽  
K.J. Motil ◽  
V.R. Young ◽  
...  
Keyword(s):  
Plasma Leucine ◽  
Relationship Of ◽  
Tracer Enrichment

Measurement of endogenous fecal excretion and true absorption of selenium in dairy cows

1991 ◽  
Vol 71 (1) ◽  
pp. 167-174 ◽  
Author(s):  
K. M. Koenig ◽  
J. A. Shelford ◽  
W. T. Buckley
Keyword(s):  
Stable Isotope ◽  
Dairy Cows ◽  
Tissue Distribution ◽  
Key Words ◽  
Dry Matter ◽  
Isotope Ratios ◽  
Holstein Cows ◽  
Fecal Excretion ◽  
Stable Isotope Ratios ◽  
Tracer Enrichment

A method combining balance techniques with an estimate of endogenous fecal selenium (Se) was evaluated as a measure of Se absorption in dairy cows. Endogenous fecal Se was estimated based on tracer enrichment in an index tissue (or fluid) that was assumed to represent enrichment of all endogenous sources of fecal Se. Two nonlactating Holstein cows fed a low-Se diet (0.035 mg Se kg−1 dry matter) were administered 4 mg Se-76, intraruminally, each day for 5 d (days 1–5). After a 10-d equilibration period, total collections of feces and urine were made at 24-h intervals for two 5-d periods (days 16–20 and days 21–25). On day 26 the animals were sacrificed and samples of all major tissues were collected. Samples were analyzed for total Se and Se stable isotope ratios. Selenium-76 enrichment was similar in tissues considered to be contributors to endogenous fecal Se, which supported the assumption that an index tissue could be used to estimate endogenous fecal excretion of Se. Endogenous fecal Se estimated from tracer enrichment in serum and liver was 22–36% of the total fecal Se excreted. True Se absorption was 10–16% of the daily Se intake. Key words: Selenium, stable isotope, tissue distribution, endogenous excretion, absorption, dairy cows

Oxidation of glutamine by the splanchnic bed in humans

2000 ◽  
Vol 278 (4) ◽  
pp. E593-E602 ◽  
Author(s):  
M. Haisch ◽  
N. K. Fukagawa ◽  
D. E. Matthews
Keyword(s):  
Plasma Glucose ◽  
Nasogastric Tube ◽  
Healthy Subjects ◽  
The Other ◽  
First Pass ◽  
Minor Portion ◽  
A Minor ◽  
Tracer Enrichment

[1,2-13C2]glutamine and [ ring-2H5]phenylalanine were infused for 7 h into five postabsorptive healthy subjects on two occasions. On one occasion, the tracers were infused intravenously for 3.5 h and then by a nasogastric tube for 3.5 h. The order of infusion was reversed on the other occasion. From the plasma tracer enrichment measurements at plateau during the intravenous and nasogastric infusion periods, we determined that 27 ± 2% of the enterally delivered phenylalanine and 64 ± 2% of the glutamine were removed on the first pass by the splanchnic bed. Glutamine flux was 303 ± 8 μmol ⋅ kg− 1 ⋅ h− 1. Of the enterally delivered [13C]glutamine tracer, 73 ± 2% was recovered as exhaled CO2 compared with 58 ± 1% of the intravenously infused tracer. The fraction of the enterally delivered tracer that was oxidized specifically on the first pass by the splanchnic bed was 53 ± 2%, comprising 83% of the total tracer extracted. From the appearance of 13C in plasma glucose, we estimated that 7 and 10% of the intravenously and nasogastrically infused glutamine tracers, respectively, were converted to glucose. The results for glutamine flux and first-pass extraction were similar to our previously reported values when a [2-15N]glutamine tracer [Matthews DE, Morano MA, and Campbell RG, Am J Physiol Endocrinol Metab 264: E848–E854, 1993] was used. The results of [13C]glutamine tracer disposal demonstrate that the major fate of enteral glutamine extraction is for oxidation and that only a minor portion is used for gluconeogenesis.

Oxidation of glutamic acid by the splanchnic bed in humans

1995 ◽  
Vol 269 (2) ◽  
pp. E269-E276 ◽  
Author(s):  
A. Battezzati ◽  
D. J. Brillon ◽  
D. E. Matthews
Keyword(s):  
Glutamic Acid ◽  
Healthy Subjects ◽  
Glutamate Uptake ◽  
15N Tracer ◽  
Intravenous Route ◽  
First Pass ◽  
Tracer Enrichment

[1,2-13C2]glutamate and [ring-2H5]phenylalanine were infused for 7 h into postabsorptive healthy subjects on two occasions. The tracer infusion was by the intravenous route for 3.5 h and by the nasogastric route for 3.5 h. The order of tracer infusion routes was switched between the two occasions. From the plasma tracer enrichment measurements at plateau during the intravenous and enteral infusion periods, we determined that 33 +/- 3% of the enterally delivered phenylalanine and 96 +/- 1% of the glutamate were removed on the first pass by the splanchnic bed; 78 +/- 3% of the enterally delivered [13C]glutamate tracer was recovered as exhaled CO2 compared with 79 +/- 2% of the intravenously infused tracer. The fraction of the enterally delivered tracer that was sequestered specifically on the first pass by the splanchnic bed was 75 +/- 2%. These results verify the previously reported large uptake of [15N]glutamate by the splanchnic bed [Matthews et al. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E848-E854, 1993] and demonstrate that the uptake of tracer is not due to an artifactual loss of the 15N tracer by reversible transamination but to glutamate uptake for oxidation.

scholarly journals Measurement of Fractional Synthetic Rates of Multiple Protein Analytes by Triple Quadrupole Mass Spectrometry

2012 ◽  
Vol 58 (3) ◽  
pp. 619-627 ◽  
Author(s):  
Anita Y H Lee ◽  
Nathan A Yates ◽  
Marina Ichetovkin ◽  
Ekaterina Deyanova ◽  
Katie Southwick ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Turnover ◽  
Selected Reaction Monitoring ◽  
Constant Infusion ◽  
Leucine Incorporation ◽  
Multiple Protein ◽  
Sds Page ◽  
A New Technique ◽  
Highly Correlated ◽  
Tracer Enrichment

Abstract BACKGROUND Current approaches to measure protein turnover that use stable isotope-labeled tracers via GC-MS are limited to a small number of relatively abundant proteins. We developed a multiplexed liquid chromatography–selected reaction monitoring mass spectrometry (LC-SRM) assay to measure protein turnover and compared the fractional synthetic rates (FSRs) for 2 proteins, VLDL apolipoprotein B100 (VLDL apoB100) and HDL apoA-I, measured by both methods. We applied this technique to other proteins for which kinetics are not readily measured with GC-MS. METHODS Subjects were given a primed-constant infusion of [5,5,5-D3]-leucine (D3-leucine) for 15 h with blood samples collected at selected time points. Apolipoproteins isolated by SDS-PAGE from lipoprotein fractions were analyzed by GC-MS or an LC-SRM assay designed to measure the M+3/M+0 ratio at >1% D3-leucine incorporation. We calculated the FSR for each apolipoprotein by curve fitting the tracer incorporation data from each subject. RESULTS The LC-SRM method was linear over the range of tracer enrichment values tested and highly correlated with GC-MS (R2 > 0.9). The FSRs determined from both methods were similar for HDL apoA-I and VLDL apoB100. We were able to apply the LC-SRM approach to determine the tracer enrichment of multiple proteins from a single sample as well as proteins isolated from plasma after immunoprecipitation. CONCLUSIONS The LC-SRM method provides a new technique for measuring the enrichment of proteins labeled with stable isotopes. LC-SRM is amenable to a multiplexed format to provide a relatively rapid and inexpensive means to measure turnover of multiple proteins simultaneously.

Hyperinsulinemic euglycemic step clamping with tracer glucose infusion and labeled glucose infusate for assessment of acute insulin resistance in pigs

2010 ◽  
Vol 298 (6) ◽  
pp. E1305-E1312 ◽  
Author(s):  
Petter Fosse Gjessing ◽  
Ole-Martin Fuskevåg ◽  
Martin Hagve ◽  
Arthur Revhaug ◽  
Øivind Irtun
Keyword(s):  
Insulin Resistance ◽  
Insulin Dose ◽  
Glucose Infusion ◽  
Insulin Clearance ◽  
Whole Body ◽  
Glucose Disposal ◽  
Surgical Trauma ◽  
Response Characteristics ◽  
Surgical Instrumentation ◽  
Tracer Enrichment

The present study aimed to establish hyperinsulinemic euglycemic step clamping with tracer glucose infusion and labeled glucose infusate (step hot-GINF HEC) for assessment of acute insulin resistance in anesthetized pigs and to arrange for combination with invasive investigative methods. Tracer enrichment was measured during d-[6,6-2H2]glucose infusion before and after surgical instrumentation ( n = 8). Insulin dose-response characteristics were determined by two step hot-GINF HEC procedures, with accordingly labeled glucose infusates performed at a total of six insulin infusion rates ranging from 0.2 to 2.0 mU·kg−1·min−1 ( n = 8). Finally, three-step hot-GINF HEC (0.4, 1.2, and 2.0 mU·kg−1·min−1) was performed subsequent to major surgical trauma ( n = 8). Tracer enrichment, basal glucose kinetics, and circulating levels of C-peptide, cortisol, glucagon, and catecholamines were not influenced by surgical instrumentation. Mean intraindividual coefficient of variance levels for glucose infusion rates and repeatedly measured insulin, glucose, and tracer enrichment indicated stable clamping conditions. Basal and maximal insulin-stimulated glucose utilization was twice as high as in humans at ∼5.5 and 21 mg·kg−1·min−1. Surgical trauma elicited pronounced peripheral and moderate hepatic insulin unresponsiveness (45% lower whole body glucose disposal and 19% less suppressed endogenous glucose release) and apparently diminished metabolic insulin clearance. Step hot-GINF HEC seems suitable for assessment of acute insulin resistance in anesthetized pigs, and combination with invasive investigative methods requiring surgical instrumentation can be accomplished without the premises for utilization of the technique being altered, but attention must be paid to alterations in metabolic insulin clearance.

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