scholarly journals Quantification of Rifapentine, a Potent Antituberculosis Drug, from Dried Blood Spot Samples Using Liquid Chromatographic-Tandem Mass Spectrometric Analysis

2014 ◽  
Vol 58 (11) ◽  
pp. 6747-6757 ◽  
Author(s):  
Teresa L. Parsons ◽  
Mark A. Marzinke ◽  
Thuy Hoang ◽  
Erin Bliven-Sizemore ◽  
Marc Weiner ◽  
...  
Keyword(s):  
Whole Blood ◽  
Dried Blood Spots ◽  
Population Based ◽  
Spectrometric Analysis ◽  
Tandem Mass ◽  
Antituberculosis Drug ◽  
Dose Escalation Study ◽  
Drug Concentrations ◽  
Tandem Mass Spectrometric ◽  
Finger Stick

ABSTRACTThe quantification of antituberculosis drug concentrations in multinational trials currently requires the collection of modest blood volumes, centrifugation, aliquoting of plasma, freezing, and keeping samples frozen during shipping. We prospectively enrolled healthy individuals into the Tuberculosis Trials Consortium Study 29B, a phase I dose escalation study of rifapentine, a rifamycin under evaluation in tuberculosis treatment trials. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying rifapentine in whole blood on dried blood spots (DBS) to facilitate pharmacokinetic/pharmacodynamic analyses in clinical trials. Paired plasma and whole-blood samples were collected by venipuncture, and whole blood was spotted on Whatman protein saver 903 cards. The methods were optimized for plasma and then validated for DBS. The analytical measuring range for quantification of rifapentine and its metabolite was 50 to 80,000 ng/ml in whole-blood DBS. The analyte was stable on the cards for 11 weeks with a desiccant at room temperature and protected from light. The method concordance for paired plasma and whole-blood DBS samples was determined after correcting for participant hematocrit or population-based estimates of bias from Bland-Altman plots. The application of either correction factor resulted in acceptable correlation between plasma and whole-blood DBS (Passing-Bablok regression corrected for hematocrit;y= 0.98x+ 356). Concentrations of rifapentine may be determined from whole-blood DBS collected via venipuncture after normalization in order to account for the dilutional effects of red blood cells. Additional studies are focused on the application of this methodology to capillary blood collected by finger stick. The simplicity of processing, storage, shipping, and low blood volume makes whole-blood DBS attractive for rifapentine pharmacokinetic evaluations, especially in international and pediatric trials.

scholarly journals Tandem Mass Spectrometric Analysis for Amino, Organic, and Fatty Acid Disorders in Newborn Dried Blood Spots

2001 ◽  
Vol 47 (11) ◽  
pp. 1945-1955 ◽  
Author(s):  
Thomas H Zytkovicz ◽  
Eileen F Fitzgerald ◽  
Deborah Marsden ◽  
Cecilia A Larson ◽  
Vivian E Shih ◽  
...  
Keyword(s):  
Amino Acid ◽  
Multiple Reaction Monitoring ◽  
Dried Blood Spots ◽  
Spectrometric Analysis ◽  
Tandem Mass ◽  
Predictive Values ◽  
Screening Programs ◽  
Blood Spots ◽  
Chain Acyl ◽  
Tandem Mass Spectrometric

Abstract Background: Tandem mass spectrometry (MS/MS) is rapidly being adopted by newborn screening programs to screen dried blood spots for >20 markers of disease in a single assay. Limited information is available for setting the marker cutoffs and for the resulting positive predictive values. Methods: We screened >160 000 newborns by MS/MS. The markers were extracted from blood spots into a methanol solution with deuterium-labeled internal standards and then were derivatized before analysis by MS/MS. Multiple reaction monitoring of each sample for the markers of interest was accomplished in ∼1.9 min. Cutoffs for each marker were set at 6–13 SD above the population mean. Results: We identified 22 babies with amino acid disorders (7 phenylketonuria, 11 hyperphenylalaninemia, 1 maple syrup urine disease, 1 hypermethioninemia, 1 arginosuccinate lyase deficiency, and 1 argininemia) and 20 infants with fatty and organic acid disorders (10 medium-chain acyl-CoA dehydrogenase deficiencies, 5 presumptive short-chain acyl-CoA dehydrogenase deficiencies, 2 propionic acidemias, 1 carnitine palmitoyltransferase II deficiency, 1 methylcrotonyl-CoA carboxylase deficiency, and 1 presumptive very-long chain acyl-CoA dehydrogenase deficiency). Approximately 0.3% of all newborns screened were flagged for either amino acid or acylcarnitine markers; approximately one-half of all the flagged infants were from the 5% of newborns who required neonatal intensive care or had birth weights <1500 g. Conclusions: In screening for 23 metabolic disorders by MS/MS, an mean positive predictive value of 8% can be achieved when using cutoffs for individual markers determined empirically on newborns.

Tandem mass spectrometric determination of purine metabolites and adenosine deaminase activity for newborn screening of ADA–SCID

2015 ◽  
Vol 2 (3) ◽  
pp. 135-145 ◽  
Author(s):  
Osama Y. Al-Dirbashi ◽  
Svetlana Ogrel ◽  
Nathan McIntosh ◽  
Lauren Higgins ◽  
Christine McRoberts ◽  
...  
Keyword(s):  
Adenosine Deaminase ◽  
Severe Combined Immunodeficiency ◽  
False Negative ◽  
Screening Method ◽  
Dried Blood Spots ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Tandem Mass ◽  
Adenosine Deaminase Activity ◽  
Tandem Mass Spectrometric

Background: Screening newborns for severe combined immunodeficiency (SCID) aims for early identification and treatment of the affected newborns. Adenosine deaminase (ADA) deficiency, a defect in the purine metabolic pathway, is a major cause of SCID and is characterized by the accumulation of adenosine (Ado) and deoxyadenosine (dAdo) in dried blood spots (DBSs). If left untreated, infants with this disorder are at risk of life-threatening infections. Analysis of T-cell receptor excision circles (TRECs) in DBS samples is the gold-standard screening method. However, TREC analysis is insufficient to determine SCID etiology, and a fraction of ADA–SCID may not be detected.Methods: We used the original DBS screening sample to measure Ado, dAdo, and ADA activity. Erythro-9-(2-hydroxy-3-nonyl) adenine was used as an ADA inhibitor to imitate ADA deficiency, making it possible to create quality control material with pathological enzyme activity and metabolite levels. Quantification was achieved by tandem mass spectrometric analysis with a run time of 2.5 min.Results: The 95th percentile reference intervals (n = 588) of Ado and dAdo were 0.9–3.0 and 0.1–0.4 µmol/L, respectively. The 95th percentile reference interval (n = 200) of ADA activity using13C10,15N5Ado and15N5dAdo as substrates were 0.8–1.6 and 0.4–0.7 pmol/DBS, respectively. In confirmed ADA patients (n = 4), Ado and dAdo were significantly elevated, whereas ADA activity was almost absent.Conclusion: These novel methods are applied, in our lab, to samples with low TRECs, with no false negative or false positives encountered to date. The potential of using these methods as a primary screening approach for ADA–SCID is in the process of validation.Statement of novelty: New mass spectrometric methods to simultaneously measure adenosine, deoxyadenosine, guanosine, and deoxguanosine, as well as ADA activity in neonatal DBS samples have been developed. This methodology highlights the metabolic nature of ADA–SCID and complements TREC analysis by providing additional biochemical information.

scholarly journals Quantitation of fentanyl analogs in dried blood spots by flow-through desorption coupled to online solid phase extraction tandem mass spectrometry

2017 ◽  
Vol 9 (25) ◽  
pp. 3876-3883 ◽  
Author(s):  
Rebecca L. Shaner ◽  
Nicholas D. Schulze ◽  
Craig Seymour ◽  
Elizabeth I. Hamelin ◽  
Jerry D. Thomas ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Dried Blood Spots ◽  
Spectrometric Analysis ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Online Solid Phase Extraction ◽  
Fentanyl Analogs ◽  
Flow Through ◽  
Tandem Mass Spectrometric

An automated dried blood spot (DBS) elution coupled with solid phase extraction and tandem mass spectrometric analysis for multiple fentanyl analogs was developed and assessed.

scholarly journals Brain Levels of Prostaglandins, Endocannabinoids, and Related Lipids Are Affected by Mating Strategies

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Jordyn M. Stuart ◽  
Jason J. Paris ◽  
Cheryl Frye ◽  
Heather B. Bradshaw
Keyword(s):  
Sexual Differentiation ◽  
Home Cage ◽  
Mating Strategies ◽  
Spectrometric Analysis ◽  
Tandem Mass ◽  
Reproductive Behaviors ◽  
Tandem Mass Spectrometric Analysis ◽  
Tandem Mass Spectrometric ◽  
Endogenous Cannabinoids ◽  
The Brain

Background. Endogenous cannabinoids (eCBs) are involved in the development and regulation of reproductive behaviors. Likewise, prostaglandins (PGs) drive sexual differentiation and initiation of ovulation. Here, we use lipidomics strategies to test the hypotheses that mating immediately activates the biosynthesis and/or metabolism of eCBs and PGs and that specific mating strategies differentially regulate these lipids in the brain.Methods. Lipid extractions and tandem mass spectrometric analysis were performed on brains from proestrous rats that had experienced one of two mating strategies (paced or standard mating) and two nonmated groups (chamber exposed and home cage controls). Levels of PGs (PGE2 and PGF2alpha), eCBs (AEA and 2-AG,N-arachidonoyl glycine), and 4 related lipids (4N-acylethanolamides) were measured in olfactory bulb, hypothalamus, hippocampus, thalamus, striatum, midbrain, cerebellum, and brainstem.Results. Overall, levels of these lipids were significantly lower among paced compared to standard mated rats with the most dramatic decreases observed in brainstem, hippocampus, midbrain, and striatum. However, chamber exposed rats had significantly higher levels of these lipids compared to home cage controls and paced mated wherein the hippocampus showed the largest increases.Conclusions. These data demonstrate that mating strategies and exposure to mating arenas influence lipid signaling in the brain.

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