A simple LC-MS/MS method using HILIC chromatography for the determination of fosfomycin in plasma and urine: application to a pilot pharmacokinetic study in humans.

PubMed

Parker, Suzanne L; Lipman, Jeffrey; Roberts, Jason A; Wallis, Steven C

2015-02-01

A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, using hydrophilic interaction liquid chromatography (HILIC) chromatography for the analysis of fosfomycin in human plasma and urine, has been developed and validated. The plasma method uses a simple protein precipitation using a low volume sample (10 μL) and is suitable for the concentration range of 1 to 2000 μg/mL. The urine method involves a simple dilution of 10 μL of sample and is suitable for a concentration range of 0.1 to 10 mg/mL. The plasma and urine results, reported, respectively, are for recovery (68, 72%), inter-assay precision (≤9.1%, ≤8.1%) and accuracy (range -7.2 to 3.3%, -1.9 to 1.6%), LLOQ precision (4.7%, 3.1%) and accuracy (1.7% and 1.2%), and includes investigations into the linearity, stability and matrix effects. The method was used in a pilot pharmacokinetic study of a critically ill patient receiving i.v. fosfomycin, which measured a maximum and minimum plasma concentration of 222 μg/mL and 172 μg/mL, respectively, after the initial dose, and a maximum and minimum plasma concentration of 868 μg/mL and 591μg/mL, respectively, after the fifth dose. The urine concentration was 2.03 mg/mL after the initial dose and 0.29 mg/mL after the fifth dose. Copyright © 2014 Elsevier B.V. All rights reserved.

Vitamin C Nutrition in Cattle

PubMed Central

Matsui, T.

2012-01-01

Domestic animals, including ruminants, can synthesize vitamin C (VC) in their liver; as such, the dietary requirement for VC has not been confirmed in these animals. The adequacy of VC has been evaluated by quantifying VC levels in plasma, but the reported values in bovine plasma have been widely variable. Plasma VC concentration is decreased by heat stress, hepatic lesions, fattening, and infectious diseases such as mastitis in cattle. Therefore, VC supplementation is potentially beneficial for cattle with low plasma VC concentration. This review discusses the methods for determination of plasma VC concentration in cattle, VC nutrition, and the efficacy of VC supplementation in calves, dairy cattle, and beef cattle. Additionally I propose a reference range for plasma VC concentration in Japanese Black cattle. PMID:25049602

A simple method for plasma total vitamin C analysis suitable for routine clinical laboratory use.

PubMed

Robitaille, Line; Hoffer, L John

2016-04-21

In-hospital hypovitaminosis C is highly prevalent but almost completely unrecognized. Medical awareness of this potentially important disorder is hindered by the inability of most hospital laboratories to determine plasma vitamin C concentrations. The availability of a simple, reliable method for analyzing plasma vitamin C could increase opportunities for routine plasma vitamin C analysis in clinical medicine. Plasma vitamin C can be analyzed by high performance liquid chromatography (HPLC) with electrochemical (EC) or ultraviolet (UV) light detection. We modified existing UV-HPLC methods for plasma total vitamin C analysis (the sum of ascorbic and dehydroascorbic acid) to develop a simple, constant-low-pH sample reduction procedure followed by isocratic reverse-phase HPLC separation using a purely aqueous low-pH non-buffered mobile phase. Although EC-HPLC is widely recommended over UV-HPLC for plasma total vitamin C analysis, the two methods have never been directly compared. We formally compared the simplified UV-HPLC method with EC-HPLC in 80 consecutive clinical samples. The simplified UV-HPLC method was less expensive, easier to set up, required fewer reagents and no pH adjustments, and demonstrated greater sample stability than many existing methods for plasma vitamin C analysis. When compared with the gold-standard EC-HPLC method in 80 consecutive clinical samples exhibiting a wide range of plasma vitamin C concentrations, it performed equivalently. The easy set up, simplicity and sensitivity of the plasma vitamin C analysis method described here could make it practical in a normally equipped hospital laboratory. Unlike any prior UV-HPLC method for plasma total vitamin C analysis, it was rigorously compared with the gold-standard EC-HPLC method and performed equivalently. Adoption of this method could increase the availability of plasma vitamin C analysis in clinical medicine.

Immunoassay and antibody microarray analysis of the HUPO Plasma Proteome Project reference specimens: Systematic variation between sample types and calibration of mass spectrometry data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haab, Brian B.; Geierstanger, Bernhard H.; Michailidis, George

2005-08-01

Four different immunoassay and antibody microarray methods performed at four different sites were used to measure the levels of a broad range of proteins (N = 323 assays; 39, 88, 168, and 28 assays at the respective sites; 237 unique analytes) in the human serum and plasma reference specimens distributed by the Plasma Proteome Project (PPP) of the HUPO. The methods provided a means to (1) assess the level of systematic variation in protein abundances associated with blood preparation methods (serum, citrate-anticoagulated-plasma, EDTA-anticoagulated-plasma, or heparin-anticoagulated-plasma) and (2) evaluate the dependence on concentration of MS-based protein identifications from data sets usingmore » the HUPO specimens. Some proteins, particularly cytokines, had highly variable concentrations between the different sample preparations, suggesting specific effects of certain anticoagulants on the stability or availability of these proteins. The linkage of antibody-based measurements from 66 different analytes with the combined MS/MS data from 18 different laboratories showed that protein detection and the quality of MS data increased with analyte concentration. The conclusions from these initial analyses are that the optimal blood preparation method is variable between analytes and that the discovery of blood proteins by MS can be extended to concentrations below the ng/mL range under certain circumstances. Continued developments in antibody-based methods will further advance the scientific goals of the PPP.« less

Determination of erythromycin in human plasma, using column liquid chromatography with a polymeric packing material, alkaline mobile phase and amperometric detection.

PubMed

Nilsson, L G; Walldorf, B; Paulsen, O

1987-12-25

A method based on column liquid chromatography was developed for determination of plasma concentrations of erythromycin. PRP-1, a polymeric type of packing material suitable for chromatography and amperometric detection at high pH, was used. The effect of pH on the column performance and on the electrochemical response was studied. A pH of ca. 10 was found to be optimal. After extraction with tert.-butyl methyl ether, plasma concentrations down to 0.2 mumol/l could be measured, using automated sample injection. Oleandomycin was used as internal standard. The method was used for determination of plasma concentrations in a pharmacokinetic study under steady-state conditions.

Evaluation of plasma fibrinogen concentration as a diagnostic indicator of inflammation in red-eared sliders (Trachemys scripta elegans).

PubMed

Moore, A Russell; Allender, Matthew C; Mitchell, Mark A; MacNeill, Amy L

2015-01-15

To critically evaluate plasma fibrinogen concentration as a diagnostic indicator of inflammation in red-eared sliders (Trachemys scripta elegans). Prospective induced-disease model and prospective cross-sectional study. Plasma samples from 12 purpose-bred red-eared sliders and 153 farm-raised red-eared sliders. A modification of the Jacobsson method was developed to measure fibrinogen concentration in platelet-poor plasma from red-eared sliders. Purpose-bred turtles had been inoculated with a ranavirus (n = 4) or sterile PBS solution (8) as part of another study. Farm-raised red-eared sliders were categorized as healthy (n = 138) or overtly ill (15) on the basis of physical examination findings at the time of blood sample collection. Samples from 124 of the 138 healthy red-eared sliders were used to establish a fibrinogen concentration reference interval as measured by the modified Jacobsson method. Fibrinogen concentrations in ranavirus-infected and physically ill turtles were compared with those of healthy turtles to determine whether fibrinogen concentration would be a useful diagnostic indicator of inflammation in red-eared sliders. The modified Jacobsson method was reliably used to measure fibrinogen concentration. The fibrinogen concentration reference interval from healthy reproductively active female red-eared sliders was right skewed. Fibrinogen concentration did not differ significantly between healthy red-eared sliders and ranavirus-infected or overtly ill red-eared sliders. A reference interval for red-eared slider plasma fibrinogen concentration was established and partitioned by sex to account for considerable right skewing observed for females. Fibrinogen concentration was not a useful indicator of inflammation in red-eared sliders with ranavirus infection or other overt illnesses.

Analytical performance of three whole blood point-of-care lactate devices compared to plasma lactate comparison methods and a flow-injection mass spectrometry method.

PubMed

Tolan, Nicole V; Wockenfus, Amy M; Koch, Christopher D; Crews, Bridgit O; Dietzen, Dennis J; Karon, Brad S

2017-03-01

Point of care (POC) whole blood lactate testing may facilitate rapid detection of sepsis. We evaluated three POC methods against both plasma lactate comparison methods and a flow-injection mass spectrometric (MS) method. Nova StatStrip, Abbott i-STAT CG4+ and Radiometer ABL90 POC lactate methods were evaluated against the mean of Cobas Integra 400 and Vitros 350 plasma lactate. POC methods were also compared to a flow-injection mass spectrometric assay measuring lactate in ZnSO 4 -precipitated whole blood extracts. Intra- and inter-assay precision was determined using quality control material. Method comparison included specimens from normal donors at rest, after exertion, and after spiking with lactic acid. Intra- and inter-assay coefficient of variation was <5% for i-STAT and ABL90; but ranged from 3.1-8.2% on two StatStrip meters. Mean (±SD) bias between POC and plasma lactate ranged from -0.2±0.9 (i-STAT and ABL90) to -0.4±1.2 (StatStrip) mmol/L. At concentrations >6mmol/L, all POC methods showed proportional negative bias compared to plasma methods; but this bias was not observed when compared to the MS method. Despite proportional negative bias, all POC methods demonstrated acceptable concordance (94-100%) with plasma lactate within the reference interval (<2.3mmol/L) and >4mmol/L, commonly used clinical cut-offs for detection of sepsis. POC lactate methods demonstrate acceptable concordance with plasma lactate across commonly used clinical cut-offs for detection of sepsis. Due to systematic negative bias at higher lactate concentrations, POC and plasma lactate should not be used interchangeably to monitor patients with elevated lactate concentrations. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Determination of Cefalothin and Cefazolin in Human Plasma, Urine and Peritoneal Dialysate by UHPLC-MS/MS: application to a pilot pharmacokinetic study in humans.

PubMed

Parker, Suzanne L; Guerra Valero, Yarmarly C; Roberts, Darren M; Lipman, Jeffrey; Roberts, Jason A; Wallis, Steven C

2016-06-01

An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the analysis of cefazolin and cefalothin in human plasma (total and unbound), urine and peritoneal dialysate has been developed and validated. Total plasma concentrations are measured following protein precipitation and are suitable for the concentration range of 1-500 µg/mL. Unbound concentrations are measured from ultra-filtered plasma acquired using Centrifree(®) devices and are suitable for the concentration range of 0.1-500 µg/mL for cefazolin and 1-500 µg/mL for cefalothin. The urine method is suitable for a concentration range of 0.1-20 mg/mL for cefazolin and 0.2-20 mg/mL for cefalothin. Peritoneal dialysate concentrations are measured using direct injection, and are suitable for the concentration range of 0.2-100 µg/mL for both cefazolin and cefalothin. The cefazolin and cefalothin plasma (total and unbound), urine and peritoneal dialysate results are reported for recovery, inter-assay precision and accuracy, and the lower limit of quantification, linearity, stability and matrix effects, with all results meeting acceptance criteria. The method was used successfully in a pilot pharmacokinetic study with patients with peritoneal dialysis-associated peritonitis, receiving either intraperitoneal cefazolin or cefalothin. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Pharmacokinetics of low-dose nedaplatin and validation of AUC prediction in patients with non-small-cell lung carcinoma.

PubMed

Niioka, Takenori; Uno, Tsukasa; Yasui-Furukori, Norio; Takahata, Takenori; Shimizu, Mikiko; Sugawara, Kazunobu; Tateishi, Tomonori

2007-04-01

The aim of this study was to determine the pharmacokinetics of low-dose nedaplatin combined with paclitaxel and radiation therapy in patients having non-small-cell lung carcinoma and establish the optimal dosage regimen for low-dose nedaplatin. We also evaluated predictive accuracy of reported formulas to estimate the area under the plasma concentration-time curve (AUC) of low-dose nedaplatin. A total of 19 patients were administered a constant intravenous infusion of 20 mg/m(2) body surface area (BSA) nedaplatin for an hour, and blood samples were collected at 1, 2, 3, 4, 6, 8, and 19 h after the administration. Plasma concentrations of unbound platinum were measured, and the actual value of platinum AUC (actual AUC) was calculated based on these data. The predicted value of platinum AUC (predicted AUC) was determined by three predictive methods reported in previous studies, consisting of Bayesian method, limited sampling strategies with plasma concentration at a single time point, and simple formula method (SFM) without measured plasma concentration. Three error indices, mean prediction error (ME, measure of bias), mean absolute error (MAE, measure of accuracy), and root mean squared prediction error (RMSE, measure of precision), were obtained from the difference between the actual and the predicted AUC, to compare the accuracy between the three predictive methods. The AUC showed more than threefold inter-patient variation, and there was a favorable correlation between nedaplatin clearance and creatinine clearance (Ccr) (r = 0.832, P < 0.01). In three error indices, MAE and RMSE showed significant difference between the three AUC predictive methods, and the method of SFM had the most favorable results, in which %ME, %MAE, and %RMSE were 5.5, 10.7, and 15.4, respectively. The dosage regimen of low-dose nedaplatin should be established based on Ccr rather than on BSA. Since prediction accuracy of SFM, which did not require measured plasma concentration, was most favorable among the three methods evaluated in this study, SFM could be the most practical method to predict AUC of low-dose nedaplatin in a clinical situation judging from its high accuracy in predicting AUC without measured plasma concentration.

8-Oxo-7,8-dihydroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine concentrations in various human body fluids: implications for their measurement and interpretation.

PubMed

Hu, Chiung-Wen; Cooke, Marcus S; Tsai, Yi-Hung; Chao, Mu-Rong

2015-02-01

8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) is the most investigated product of oxidatively damaged DNA lesion that has been associated with the development of aging, cancer and some degenerative diseases. Here, we present the first liquid chromatography-tandem mass spectrometry method that enables the simultaneous measurement of its repair products in plasma and saliva, namely 8-oxo-7,8-dihydroguanine (8-oxoGua) and 8-oxodGuo. Using this method, we investigated the underlying transport mechanism of the repair products of oxidatively damaged DNA between cellular compartments and biological matrices. Plasma, saliva and urine samples were collected concurrently from 57 healthy subjects. Various deproteinization methods were evaluated, and the precipitants acetonitrile and sodium hydroxide-methanol were, respectively, selected for plasma and saliva samples due to their effect on recovery efficiencies and chromatography. The mean baseline concentrations of 8-oxoGua and 8-oxodGuo in plasma were demonstrated to be 0.21 and 0.016 ng/mL, respectively, while in saliva they were 0.85 and 0.010 ng/mL, respectively. A relatively high concentration of 8-oxoGua was found in saliva with a concentration factor (CF, concentration ratio of saliva to plasma) of 4 as compared to that of 8-oxodGuo (CF: 0.6), implying that 8-oxoGua in plasma may be actively transported to saliva, whereas 8-oxodGuo was most dependent on a passive diffusion. Good correlations between urine and plasma concentrations were observed for 8-oxoGua and 8-oxodGuo, suggesting that blood was a suitable matrix in addition to urine. Significant correlation between 8-oxoGua and 8-oxodGuo in urine was only observed when the concentrations were not corrected for urinary creatinine, raising the issue of applicability of urinary creatinine to adjust 8-oxoGua concentrations.

Determination of GABA and vigabatrin in human plasma by a rapid and simple HPLC method: correlation between clinical response to vigabatrin and increase in plasma GABA.

PubMed

Löscher, W; Fassbender, C P; Gram, L; Gramer, M; Hörstermann, D; Zahner, B; Stefan, H

1993-03-01

The novel antiepileptic drug vigabatrin (Sabril) acts by inhibiting degradation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), increasing the GABA concentrations in the brain. Because the GABA degrading enzyme GABA aminotransferase (GABA-T) is also present in peripheral tissues, including blood platelets, measurement of plasma GABA levels might be a useful indication of the pharmacological response to vigabatrin during therapeutic monitoring. However, because of the very low concentrations of GABA in plasma, the few methods available for plasma GABA analysis are time-consuming, difficult to perform and/or not selective enough because of potential interference with other plasma constituents. In the present study, a rapid, selective and sensitive amino acid analysis HPLC method has been developed for plasma GABA determination with fluorescence detection, using o-phthaldialdehyde as a precolumn derivatizing agent. By employing a 3 microns particle size reversed-phase column and a multi-step gradient system of two solvents, the very low endogenous concentration of GABA in human plasma could be reproducibly quantitated without interference of other endogenous compounds. Incubation of human plasma samples with GABA degrading enzyme(s) resulted in an almost total loss of the GABA peak, thus demonstrating the specificity of the method for GABA analysis. In addition to GABA and other endogenous amino acids, the HPLC method could be used to quantitate plasma levels of vigabatrin. Thus, this improved HPLC amino acid assay might be used to examine whether concomitant monitoring of plasma GABA and vigabatrin is useful for clinical purposes. This was examined in 20 epileptic patients undergoing chronic treatment with vigabatrin. The average plasma GABA level of these 20 patients did not differ significantly from non-epileptic controls. However, when epileptic patients were subdivided according to their clinical response to vigabatrin, vigabatrin responders had significantly higher GABA levels than nonresponders or controls. In contrast to the difference in plasma GABA, vigabatrin responders and nonresponders did not differ in dose or plasma level of vigabatrin. These data may indicate that determination of plasma GABA is a valuable non-invasive method for therapeutic monitoring in patients on medication with vigabatrin.

Determination of salicylic acid by HPLC in plasma and saliva from children with juvenile chronic arthritis.

PubMed

Legaz, M E; Acitores, E; Valverde, F

1992-12-01

A high performance liquid chromatography (HPLC) method has been developed for measuring salicylic acid in the plasma and saliva of children with juvenile chronic arthritis (JCA). Samples were extracted with diethyl ether and, after drying, redissolved in methanol to be chromatographed. Quantitation of salicylic acid was performed by reverse phase HPLC on a spherisorb ODS-2 column, using methanol: water: acetic acid as mobile phase. Phenolic was monitored by absorbance at 237 nm. Linearity between the amount of mass injected and the response in the detector was determined. This method was applied to compare concentrations of salivary and plasma salicylic acid. The method also permitted the quantitation of salivary salicylate as a non-invasive, indirect method for monitoring the concentration of plasma salicylate in patients with JCA.

Validation of high-throughput methods for measuring blood urea nitrogen and urinary albumin concentrations in mice.

PubMed

Grindle, Susan; Garganta, Cheryl; Sheehan, Susan; Gile, Joe; Lapierre, Andree; Whitmore, Harry; Paigen, Beverly; DiPetrillo, Keith

2006-12-01

Chronic kidney disease is a substantial medical and economic burden. Animal models, including mice, are a crucial component of kidney disease research; however, recent studies disprove the ability of autoanalyzer methods to accurately quantify plasma creatinine levels, an established marker of kidney disease, in mice. Therefore, we validated autoanalyzer methods for measuring blood urea nitrogen (BUN) and urinary albumin concentrations, 2 common markers of kidney disease, in samples from mice. We used high-performance liquid chromatography to validate BUN concentrations measured using an autoanalyzer, and we utilized mouse albumin standards to determine the accuracy of the autoanalyzer over a wide range of albumin concentrations. We observed a significant, linear correlation between BUN concentrations measured by autoanalyzer and high-performance liquid chromatography. We also found a linear relationship between known and measured albumin concentrations, although the autoanalyzer method underestimated the known amount of albumin by 3.5- to 4-fold. We confirmed that plasma and urine constituents do not interfere with the autoanalyzer methods for measuring BUN and urinary albumin concentrations. In addition, we verified BUN and albuminuria as useful markers to detect kidney disease in aged mice and mice with 5/6-nephrectomy. We conclude that autoanalyzer methods are suitable for high-throughput analysis of BUN and albumin concentrations in mice. The autoanalyzer accurately quantifies BUN concentrations in mouse plasma samples and is useful for measuring urinary albumin concentrations when used with mouse albumin standards.

Validation and use of three complementary analytical methods (LC-FLS, LC-MS/MS and ICP-MS) to evaluate the pharmacokinetics, biodistribution and stability of motexafin gadolinium in plasma and tissues.

PubMed

Miles, Dale R; Mesfin, Mimi; Mody, Tarak D; Stiles, Mark; Lee, Jean; Fiene, John; Denis, Bernie; Boswell, Garry W

2006-05-01

Liquid chromatography-fluorescence (LC-FLS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma-mass spectrometry (ICP-MS) methods were developed and validated for the evaluation of motexafin gadolinium (MGd, Xcytrin) pharmacokinetics and biodistribution in plasma and tissues. The LC-FLS method exhibited the greatest sensitivity (0.0057 microg mL(-1)), and was used for pharmacokinetic, biodistribution, and protein binding studies with small sample sizes or low MGd concentrations. The LC-MS/MS method, which exhibited a short run time and excellent selectivity, was used for routine clinical plasma sample analysis. The ICP-MS method, which measured total Gd, was used in conjunction with LC methods to assess MGd stability in plasma. All three methods were validated using human plasma. The LC-FLS method was also validated using plasma, liver and kidneys from mice and rats. All three methods were shown to be accurate, precise and robust for each matrix validated. For three mice, the mean (standard deviation) concentration of MGd in plasma/tissues taken 5 hr after dosing with 23 mg kg(-1) MGd was determined by LC-FLS as follows: plasma (0.025+/-0.002 microg mL(-1)), liver (2.89+/-0.45 microg g(-1)), and kidney (6.09+/-1.05 microg g(-1)). Plasma samples from a subset of patients with brain metastases from extracranial tumors were analyzed using both LC-MS/MS and ICP-MS methods. For a representative patient, > or = 90% of the total Gd in plasma was accounted for as MGd over the first hour post dosing. By 24 hr post dosing, 63% of total Gd was accounted for as MGd, indicating some metabolism of MGd.

Effects of Cytochrome P450 (CYP) 2C19 Genotypes on Steady-State Plasma Concentrations of Escitalopram and its Desmethyl Metabolite in Japanese Patients With Depression.

PubMed

Tsuchimine, Shoko; Ochi, Shinichiro; Tajiri, Misuzu; Suzuki, Yutaro; Sugawara, Norio; Inoue, Yoshimasa; Yasui-Furukori, Norio

2018-06-01

Plasma concentrations of the S-enantiomer of citalopram were different between extensive and poor CYP2C19 metabolizers in healthy subjects and depressed patients. However, most studies applied dose-corrected concentrations. Thus, we studied the effects of polymorphisms of the CYP2C19 gene on raw plasma drug concentrations in Japanese patients with depression. Subjects in this study consisted of 412 depressed patients receiving 5, 10, 15, or 20 mg of escitalopram once a day. Plasma concentrations of escitalopram and desmethylescitalopram were quantified using HPLC. CYP2C19 genotypes were identified using polymerase chain reaction methods. There were no differences in the steady-state plasma concentrations of escitalopram or desmethylescitalopram in each dose group (5, 10, 15, or 20 mg of escitalopram) among CYP2C19 genotype groups. However, 1-way analysis of variance showed significant effects of CYP2C19 genotypes on the dose-adjusted plasma concentration of escitalopram but not in the dose-adjusted plasma concentration of desmethylescitalopram. Analysis of covariance including age, sex, and body weight showed significant effects of CYP2C19 genotypes on the dose-adjusted plasma concentration of escitalopram and the ratio of desmethylescitalopram to escitalopram. These findings suggest that the CYP2C19 variants are associated with steady-state plasma concentrations of escitalopram to some extent but are not associated with desmethylescitalopram.

Pulmonary permeability assessed by fluorescent-labeled dextran instilled intranasally into mice with LPS-induced acute lung injury.

PubMed

Chen, Honglei; Wu, Shaoping; Lu, Rong; Zhang, Yong-guo; Zheng, Yuanyuan; Sun, Jun

2014-01-01

Several different methods have been used to assess pulmonary permeability in response to acute lung injury (ALI). However, these methods often involve complicated procedures and algorithms that are difficult to precisely control. The purpose of the current study is to establish a feasible method to evaluate alterations in lung permeability by instilling fluorescently labeled dextran (FITC-Dextran) intranasally. For the mouse model of direct ALI, lipopolysaccharide (LPS) was administered intranasally. FITC-Dextran was instilled intranasally one hour before the mice were euthanized. Plasma fluorescence intensities from the LPS group were significantly higher than in the control group. To determine the reliability and reproducibility of the procedure, we also measured the lung wet-to-dry weight ratio, the protein concentration of the bronchoalveolar lavage fluid, tight and adherens junction markers and pathological changes. Consistent results were observed when the LPS group was compared with the control group. Simultaneously, we found that the concentration of plasma FITC-Dextran was LPS dose-dependent. The concentration of plasma FITC-Dextran also increased with initial intranasal FITC-Dextran doses. Furthermore, increased fluorescence intensity of plasma FITC-Dextran was found in the intraperitoneally LPS-induced ALI model. In conclusion, the measurement of FITC-Dextran in plasma after intranasal instillation is a simple, reliable, and reproducible method to evaluate lung permeability alterations in vivo. The concentration of FITC-Dextran in the plasma may be useful as a potential peripheral biomarker of ALI in experimental clinical studies.

Pharmacokinetics and pharmacodynamics study of rhein treating renal fibrosis based on metabonomics approach.

PubMed

Sun, Hao; Luo, Guangwen; Xiang, Zheng; Cai, Xiaojun; Chen, Dahui

2016-12-01

The selection of effect indicators in the pharmacokinetic/ pharmacodynamic study of complex diseases to describe the relationship between plasma concentration and effect indicators is difficult. Three effect indicators of renal fibrosis were successfully determined. The relationship between pharmacokinetics and pharmacodynamics of rhein in rhubarb was elucidated. The study was a metabolomics analysis of rat plasma and pharmacokinetics/ pharmacodynamics of rhein. A sensitive and simple ultra performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-MS/MS) method was applied to determine the rhein plasma concentration in the rat model of renal fibrosis and rat sham-operated group after the administration of rhubarb decoction. Then, the ultra performance liquid chromatography-Micromass quadrupole-time of flight mass spectrometry (UPLC-QTOF/MS) metabolomics method was used to screen biomarkers of renal fibrosis in rat plasma. Furthermore, the relationship between the plasma concentration of rhein and the concentration of three biomarkers directly related to renal fibrosis were analyzed. The three screened biomarkers could represent the effect of rhein treatment on renal fibrosis. Increasing the plasma concentration of rhein tended to restore the concentration of the three biomarkers in the model group compared with that in the sham-operated group. Evident differences in the area under the plasma concentration-time curve (AUC) of rhein were also observed under different pathological states. The results provide valuable information for the clinical application of rhubarb. Rhein intervention could recover the physiological balance in living organisms from the pharmacokinetic/pharmacodynamic levels. New information on the pharmacokinetic/pharmacodynamic study of complex diseases is provided. Copyright © 2016 Elsevier GmbH. All rights reserved.

Pharmacokinetic study of arctigenin in rat plasma and organ tissue by RP-HPLC method.

PubMed

He, Fan; Dou, De-Qiang; Hou, Qiang; Sun, Yu; Kang, Ting-Guo

2013-01-01

A high-performance liquid chromatography (HPLC) technique was developed for the determination of arctigenin in plasma and various organs of rats after the oral administration of 30, 50 and 70 mgkg(-1) of arctigenin to the Sprague-Dawley rats. Results showed that the validated HPLC method was simple, fast, reproducible and suitable to the determination of arctigenin in rat plasma and organ tissue and one-compartmental model with zero-order absorption process can well describe the changes of arctigenin concentration in the plasma. The concentration of compound was highest in the spleen, less in the liver and the least in the lung.

[Determination of acyclovir in mouse plasma and tissues by reversed-phase high performance liquid chromatography].

PubMed

Xu, Y; Zhou, S W; Tang, J L; Huang, L Q

2001-11-01

The aim of this study was to establish an high performance liquid chromatographic method for determining acyclovir (ACV) concentration in mouse plasma and tissues. A solution of 0.25 mL 60 g/L perchloric acid and 0.25 mL acetonitrile was added into 0.2 mL plasma or 0.2 g tissues to precipitate proteins. Following centrifugation, the supernatant obtained was injected into a reversed-phase column. Operating conditions were Hypersil ODS column(250 mm x 4.6 mm i.d., 5 microns), methanol-water-acetic acid(1:99:0.5, volume ratio) solution as mobile phase at a flow rate of 1.5 mL/min, UV detection at 252 nm. The detection limit of ACV concentration in plasma was 20 micrograms/L and that in tissues was 50 ng/g. The standard curves for ACV were linear in plasma and homogenate of tissues (r > 0.99). The precision of the method was good and the recoveries of ACV were higher than 97.5%. So this method is rapid, accurate and convenient for determination of ACV concentrations in plasma and tissues.

Plasma concentration-dependent suppression of endogenous hydrocortisone in the horse after intramuscular administration of dexamethasone-21-isonicotinate.

PubMed

Ekstrand, C; Bondesson, U; Gabrielsson, J; Hedeland, M; Kallings, P; Olsén, L; Ingvast-Larsson, C

2015-06-01

Detection times and screening limits (SL) are methods used to ensure that the performance of horses in equestrian sports is not altered by drugs. Drug concentration-response relationship and knowledge of concentration-time profiles in both plasma and urine are required. In this study, dexamethasone plasma and urine concentration-time profiles were investigated. Endogenous hydrocortisone plasma concentrations and their relationship to dexamethasone plasma concentrations were also explored. A single dose of dexamethasone-21-isonicotinate suspension (0.03 mg/kg) was administered intramuscularly to six horses. Plasma was analysed for dexamethasone and hydrocortisone and urine for dexamethasone, using UPLC-MS/MS. Dexamethasone was quantifiable in plasma for 8.3 ± 2.9 days (LLOQ: 0.025 μg/L) and in urine for 9.8 ± 3.1 days (LLOQ: 0.15 μg/L). Maximum observed dexamethasone concentration in plasma was 0.61 ± 0.12 μg/L and in urine 4.2 ± 0.9 μg/L. Terminal plasma half-life was 38.7 ± 19 h. Hydrocortisone was significantly suppressed for 140 h. The plasma half-life of hydrocortisone was 2.7 ± 1.3 h. Dexamethasone potency, efficacy and sigmoidicity factor for hydrocortisone suppression were 0.06 ± 0.04 μg/L, 0.95 ± 0.04 and 6.2 ± 4.6, respectively. Hydrocortisone suppression relates to the plasma concentration of dexamethasone. Thus, determination of irrelevant plasma concentrations and SL is possible. Future research will determine whether hydrocortisone suppression can be used as a biomarker of the clinical effect of dexamethasone. © 2014 John Wiley & Sons Ltd.

Analysis of concentration and (13)C enrichment of D-galactose in human plasma.

PubMed

Schadewaldt, P; Hammen, H W; Loganathan, K; Bodner-Leidecker, A; Wendel, U

2000-05-01

A stable-isotope dilution method for the sensitive determination of D-galactose in human plasma was established. D-[(13)C]Galactose was added to plasma, and the concentration was measured after D-glucose was removed from the plasma by treatment with D-glucose oxidase and the sample was purified by ion-exchange chromatography. For gas chromatographic-mass spectrometric analysis, aldononitrile pentaacetate derivatives were prepared. Monitoring of the [MH-60](+) ion intensities at m/z 328, 329, and 334 in the positive chemical ionization mode allowed the assessment of 1-(12)C-, 1-(13)C-, and U-(13)C(6)-labeled D-galactose, respectively. The D-galactose concentration was quantified on the basis of the (13)C-labeled internal standard. The method was linear (range examined, 0.1-5 micromol/L) and of good repeatability in the low and high concentration ranges (within- and between-run CVs <15%). The limit of quantification for plasma D-galactose was <0.02 micromol/L. Measurements in plasma of postabsorptive subjects yielded D-galactose concentrations (mean +/- SD) of 0.12 +/- 0.03 (n = 16), 0.11 +/- 0.04 (n = 15), 1.44 +/- 0.54 (n = 10), and 0.17 +/- 0.07 (n = 5) micromol/L in healthy adults, diabetic patients, patients with classical galactosemia, and obligate heterozygous parents thereof, respectively. These data were considerably lower (3- to 18-fold) than the values of a conventional enzymatic assay. The procedure was also applied successfully in a stable-isotope turnover study to evaluate endogenous D-galactose formation. The present findings establish that detection of D-galactose from endogenous sources is feasible in human plasma and show that erroneously high results may be obtained by enzymatic methods.

Validation of a new point-of-care assay for determination of β-carotene concentration in bovine whole blood and plasma.

PubMed

Raila, Jens; Enjalbert, Francis; Mothes, Ralf; Hurtienne, Andrea; Schweigert, Florian J

2012-03-01

β-Carotene is an important precursor of vitamin A, and is associated with bovine fertility. β-Carotene concentrations in plasma are used to optimize β-carotene supplementation in cattle, but measurement requires specialized equipment to separate plasma and extract and measure β-carotene, either using spectrophotometry or high performance liquid chromatography (HPLC). The objective of this study was to validate a new 2-step point-of-care (POC) assay for measuring β-carotene in whole blood and plasma. β-carotene concentrations in plasma from 166 cows were measured using HPLC and compared with results obtained using a POC assay, the iCheck-iEx-Carotene test kit. Whole blood samples from 23 of these cattle were also evaluated using the POC assay and compared with HPLC-plasma results from the same 23 animals. The POC assay includes an extraction vial (iEx Carotene) and hand-held photometer (iCheck Carotene). Concentrations of β-carotene in plasma measured using the POC assay ranged from 0.40 to 15.84 mg/L (n = 166). No differences were observed between methods for assay of plasma (mean ± SD; n = 166): HPLC-plasma 4.23 ± 2.35 mg/L; POC-plasma 4.49 ± 2.36 mg/L. Similar good agreement was found when plasma analyzed using HPLC was compared with whole blood analyzed using the POC system (n = 23): HPLC-plasma 3.46 ± 2.12 mg/L; POC-whole blood 3.67 ± 2.29 mg/L. Concentrations of β-carotene can be measured in blood and plasma from cattle easily and rapidly using a POC assay, and results are comparable to those obtained by the highly sophisticated HPLC method. Immediate feedback regarding β-carotene deficiency facilitates rapid and appropriate optimization of β-carotene supplementation in feed. © 2012 American Society for Veterinary Clinical Pathology.

Method of high-precision microsampled blood and plasma mass densitometry

NASA Technical Reports Server (NTRS)

Hinghofer-Szalkay, H.

1986-01-01

The reliability of the mechanical oscillator technique for blood and plasma density measurements on samples of volumes less than 0.1 ml is examined, and a precision of 0.001 g/l is found if plasma-isodensic heparin solution and siliconized densitometers are employed. Sources of measurement errors in the density determinations include storage of plasma samples, inhomogeneity of blood samples, and density reading before adequate temperature equilibration. In tests of plasma sample storage, the best reproducibility was obtained with samples kept at 4 C. Linear correlations were found between plasma density and plasma protein concentration, blood density and blood hemoglobin concentration, and erythrocyte density and MCHC.

Oral Fluid and Plasma Cannabinoid Ratios after Around-the-Clock Controlled Oral Δ9-Tetrahydrocannabinol Administration

PubMed Central

Milman, Garry; Schwope, David M.; Schwilke, Eugene W.; Darwin, William D.; Kelly, Deanna L.; Goodwin, Robert S.; Gorelick, David A.; Huestis, Marilyn A.

2013-01-01

BACKGROUND Oral fluid (OF) testing is increasingly important for drug treatment, workplace, and drugged-driving programs. There is interest in predicting plasma or whole-blood concentrations from OF concentrations; however, the relationship between these matrices is incompletely characterized because of few controlled drug-administration studies. METHODS Ten male daily cannabis smokers received around-the-clock escalating 20-mg oral Δ9-tetrahydrocannabinol (THC, dronabinol) doses (40–120 mg/day) for 8 days. Plasma and OF samples were simultaneously collected before, during, and after dosing. OF THC, 11-hydroxy-THC and 11-nor-9-carboxy-THC (THCCOOH) were quantified by GC-MS at 0.5-μg/L, 0.5-μg/L, and 7.5-ng/L limits of quantification (LOQs), respectively. In plasma, the LOQs were 0.25 μg/L for THC and THCCOOH, and 0.5 μg/L for 11-hydroxy-THC. RESULTS Despite multiple oral THC administrations each day and increasing plasma THC concentrations, OF THC concentrations generally decreased over time, reflecting primarily previously self-administered smoked cannabis. The logarithms of the THC concentrations in oral fluid and plasma were not significantly correlated (r = −0.10; P = 0.065). The OF and plasma THCCOOH concentrations, albeit with 1000-fold higher concentrations in plasma, increased throughout dosing. The logarithms of OF and plasma THCCOOH concentrations were significantly correlated (r = 0.63; P < 0.001), although there was high interindividual variation. A high OF/plasma THC ratio and a high OF THC/THCCOOH ratio indicated recent cannabis smoking. CONCLUSIONS OF monitoring does not reliably detect oral dronabinol intake. The time courses of THC and THCCOOH concentrations in plasma and OF were different after repeated oral THC doses, and high inter-individual variation was observed. For these reasons, OF cannabinoid concentrations cannot predict concurrent plasma concentrations. PMID:21875944

Use of refractometry for determination of psittacine plasma protein concentration.

PubMed

Cray, Carolyn; Rodriguez, Marilyn; Arheart, Kristopher L

2008-12-01

Previous studies have demonstrated both poor and good correlation of total protein concentrations in various avian species using refractometry and biuret methodologies. The purpose of the current study was to compare these 2 techniques of total protein determination using plasma samples from several psittacine species and to determine the effect of cholesterol and other solutes on refractometry results. Total protein concentration in heparinized plasma samples without visible lipemia was analyzed by refractometry and an automated biuret method on a dry reagent analyzer (Ortho 250). Cholesterol, glucose, and uric acid concentrations were measured using the same analyzer. Results were compared using Deming regression analysis, Bland-Altman bias plots, and Spearman's rank correlation. Correlation coefficients (r) for total protein results by refractometry and biuret methods were 0.49 in African grey parrots (n=28), 0.77 in Amazon parrots (20), 0.57 in cockatiels (20), 0.73 in cockatoos (36), 0.86 in conures (20), and 0.93 in macaws (38) (P< or =.01). Cholesterol concentration, but not glucose or uric acid concentrations, was significantly correlated with total protein concentration obtained by refractometry in Amazon parrots, conures, and macaws (n=25 each, P<.05), and trended towards significance in African grey parrots and cockatoos (P=.06). Refractometry can be used to accurately measure total protein concentration in nonlipemic plasma samples from some psittacine species. Method and species-specific reference intervals should be used in the interpretation of total protein values.

Platelet-rich plasma differs according to preparation method and human variability.

PubMed

Mazzocca, Augustus D; McCarthy, Mary Beth R; Chowaniec, David M; Cote, Mark P; Romeo, Anthony A; Bradley, James P; Arciero, Robert A; Beitzel, Knut

2012-02-15

Varying concentrations of blood components in platelet-rich plasma preparations may contribute to the variable results seen in recently published clinical studies. The purposes of this investigation were (1) to quantify the level of platelets, growth factors, red blood cells, and white blood cells in so-called one-step (clinically used commercial devices) and two-step separation systems and (2) to determine the influence of three separate blood draws on the resulting components of platelet-rich plasma. Three different platelet-rich plasma (PRP) separation methods (on blood samples from eight subjects with a mean age [and standard deviation] of 31.6 ± 10.9 years) were used: two single-spin processes (PRPLP and PRPHP) and a double-spin process (PRPDS) were evaluated for concentrations of platelets, red and white blood cells, and growth factors. Additionally, the effect of three repetitive blood draws on platelet-rich plasma components was evaluated. The content and concentrations of platelets, white blood cells, and growth factors for each method of separation differed significantly. All separation techniques resulted in a significant increase in platelet concentration compared with native blood. Platelet and white blood-cell concentrations of the PRPHP procedure were significantly higher than platelet and white blood-cell concentrations produced by the so-called single-step PRPLP and the so-called two-step PRPDS procedures, although significant differences between PRPLP and PRPDS were not observed. Comparing the results of the three blood draws with regard to the reliability of platelet number and cell counts, wide variations of intra-individual numbers were observed. Single-step procedures are capable of producing sufficient amounts of platelets for clinical usage. Within the evaluated procedures, platelet numbers and numbers of white blood cells differ significantly. The intra-individual results of platelet-rich plasma separations showed wide variations in platelet and cell numbers as well as levels of growth factors regardless of separation method.

Correlations between plasma noradrenaline concentrations, antioxidants, and neutrophil counts after submaximal resistance exercise in men

PubMed Central

Ramel, A; Wagner, K; Elmadfa, I

2004-01-01

Objectives: To investigate noradrenaline concentrations, neutrophil counts, plasma antioxidants, and lipid oxidation products before and after acute resistance exercise. Methods: 17 male participants undertook a submaximal resistance exercise circuit (10 exercises; 75% of the one repetition maximum; mean (SD) exercise time, 18.6 (1.1) minutes). Blood samples were taken before and immediately after exercise and analysed for plasma antioxidants, noradrenaline, neutrophils, and lipid oxidation products. Wilcoxon's signed-rank test and Pearson's correlation coefficient were used for calculations. Results: Neutrophils, noradrenaline, fat soluble antioxidants, and lipid oxidation products increased after exercise. Noradrenaline concentrations were associated with higher antioxidant concentrations. Neutrophils were related to higher concentrations of conjugated dienes. Conclusions: Submaximal resistance exercise increases plasma antioxidants. This might reflect enhanced antioxidant defence in response to the oxidative stress of exercise, though this is not efficient for inhibiting lipid oxidation. The correlation between noradrenaline concentrations and plasma antioxidants suggests a modulating role of the stress hormone. Neutrophils are a possible source of oxidative stress after resistance exercise. PMID:15388566

Measurement of tafenoquine (WR 238605) in human plasma and venous and capillary blood by high-pressure liquid chromatography.

PubMed

Kocisko, D A; Walsh, D S; Eamsila, C; Edstein, M D

2000-04-01

A simple, rapid, and accurate high-pressure liquid chromatographic method with fluorescence detection is described for the measurement of tafenoquine (TQ) (also known as WR 238605) from human plasma and venous and capillary blood. Tafenoquine was measured in plasma and venous blood following protein precipitation. Chromatographic separation was achieved using a Waters S5P Spherisorb phenyl analytical cartridge (150 mm x 4.6 mm I.D., 5 microm particle size) (Waters, Milford, MA, USA) and a mobile phase of 22 mM ammonium acetate, pH 4:acetonitrile (45:55, vol/vol). The flow rate was 1.5 mL/min and the retention times were approximately 3.5 min for WR VIIIAc (internal standard) and approximately 7.8 min for TQ. The interday and intraday coefficients of variation of TQ over a concentration range of 20-1000 ng/mL in plasma were < or =8.4% and in venous blood were < or =9.6%. The mean percent difference between added concentration and obtained concentration was 7.3% in plasma and 8.5% in venous blood over the corresponding concentration range. The limit of quantitation for both fluids was 10 ng/mL. Tafenoquine concentrations were comparable between capillary and venous blood with no significant difference between measurement in both biological fluids. The clinical application of the method was demonstrated by measuring plasma and whole blood concentrations of TQ from participants in a chemosuppression trial of the drug against malaria infections in Thailand.

Sensitive and rapid liquid chromatography/tandem mass spectrometric assay for the quantification of piperaquine in human plasma.

PubMed

Singhal, Puran; Gaur, Ashwani; Gautam, Anirudh; Varshney, Brijesh; Paliwal, Jyoti; Batra, Vijay

2007-11-01

A simple, sensitive and rapid liquid chromatography/tandem mass spectrometric (LC-MS/MS) method was developed and validated for quantification of piperaquine, an antimalarial drug, in human plasma using its structural analogue, piperazine bis chloroquinoline as internal standard (IS). The method involved a simple protein precipitation with methanol followed by rapid isocratic elution of analytes with 10mM ammonium acetate buffer/methanol/formic acid/ammonia solution (25/75/0.2/0.15, v/v) on Chromolith SpeedROD RP-18e reversed phase chromatographic column and quantification by mass spectrometry in the multiple reaction monitoring mode (MRM). The precursor to product ion transitions of m/z 535.3-->288.2 and m/z 409.1-->205.2 were used to measure the analyte and the IS, respectively. The assay exhibited a linear dynamic range of 1.0-250.2 ng/mL for piperaquine in plasma. The limit of detection (LOD) and lower limit of quantification (LLOQ) in plasma were 0.2 and 1.0 ng/mL, respectively. Acceptable precision and accuracy (+/-20% deviation for LLOQ standard and +/-15% deviation for other standards from the respective nominal concentration) were obtained for concentrations over the standard curve ranges. A run time of 2.5 min for a sample made it possible to achieve a throughput of more than 400 plasma samples analyzed per day. The validated method was successfully applied to analyze human plasma samples from phase-1 clinical studies. The mean pharmacokinetic parameters of piperaquine following 1000 mg oral dose: observed maximum plasma concentration (Cmax), time to maximum plasma concentration (Tmax) and elimination half-life (T1/2) were 46.1 ng/mL, 3.8h and 13 days, respectively.

High Throughput Determination of Critical Human Dosing ...

EPA Pesticide Factsheets

High throughput toxicokinetics (HTTK) is a rapid approach that uses in vitro data to estimate TK for hundreds of environmental chemicals. Reverse dosimetry (i.e., reverse toxicokinetics or RTK) based on HTTK data converts high throughput in vitro toxicity screening (HTS) data into predicted human equivalent doses that can be linked with biologically relevant exposure scenarios. Thus, HTTK provides essential data for risk prioritization for thousands of chemicals that lack TK data. One critical HTTK parameter that can be measured in vitro is the unbound fraction of a chemical in plasma (Fub). However, for chemicals that bind strongly to plasma, Fub is below the limits of detection (LOD) for high throughput analytical chemistry, and therefore cannot be quantified. A novel method for quantifying Fub was implemented for 85 strategically selected chemicals: measurement of Fub was attempted at 10%, 30%, and 100% of physiological plasma concentrations using rapid equilibrium dialysis assays. Varying plasma concentrations instead of chemical concentrations makes high throughput analytical methodology more likely to be successful. Assays at 100% plasma concentration were unsuccessful for 34 chemicals. For 12 of these 34 chemicals, Fub could be quantified at 10% and/or 30% plasma concentrations; these results imply that the assay failure at 100% plasma concentration was caused by plasma protein binding for these chemicals. Assay failure for the remaining 22 chemicals may

Albendazolesulphoxide concentrations in plasma and hydatid cyst and prediction of parasitological and clinical outcomes in patients with liver hydatidosis caused by Echinococcus granulosus

PubMed Central

Skuhala, Tomislava; Trkulja, Vladimir; Runje, Mislav; Vukelić, Dalibor; Desnica, Boško

2014-01-01

Aim To investigate the relationship between plasma and cyst concentrations of albendazolesulphoxide (ASO) and their effects on parasitological findings and disease recurrence in patients with liver hydatidosis. Methods The study was conducted at the University Hospital for Infectious Diseases “Dr. Fran Mihaljević,” Zagreb, Croatia, between August 2006 and January 2011. Consecutive patients (N = 48, age 6-77 years) were treated with albendazole (3 × 5 mg/kg/d) over 28 days before surgical cyst removal (n = 34) or percutaneous evacuation (PAIR) (n = 14). Plasma ASO was determined on days 10 and 28 of treatment and cyst concentrations at surgery/PAIR. Results Disease recurred in 3 surgically treated patients. Variability of ASO concentrations was substantial. Plasma concentrations on day 10 were higher than on day 28 (geometric means ratio [GMR] 2.00; 95%CI 1.38-2.91, P < 0.001) and higher than cyst concentrations at the time of treatment (GMR = 1.58, 1.01-2.34, P = 0.045). Higher cyst (but not plasma) concentrations were independently associated with lower odds of protoscolex motility (OR = 0.23, 0.01-0.70, P < 0.001) and higher odds of protoscolex destruction (OR = 1.17, 1.04-1.46, P < 0.001). With adjustment for age and protoscolex motility, higher day 10 plasma concentrations (but not cyst concentrations) were associated with lower odds of disease recurrence (OR = 0.49, 0.09-0.97, P = 0.035). Plasma concentrations did not predict cyst concentrations. Conclusion Viability of protoscolices progressively decreased with increasing ASO concentrations in the cyst. Data strongly suggested that higher plasma concentrations reduced the risk of disease recurrence. PMID:24778101

Effects of dehydration on plasma osmolality, thirst-related behavior, and plasma and brain angiotensin concentrations in Couch's spadefoot toad, Scaphiopus couchii.

PubMed

Johnson, W E; Propper, C R

2000-05-01

Under dehydrating conditions, many terrestrial vertebrates species exhibit increases in plasma osmolality and their drinking behavior. Under some circumstances, this behavioral change is accompanied by changes in plasma and central angiotensin concentrations, and it has been proposed that these changes in angiotensin levels induce the thirst-related behaviors. In response to dehydration, the spadefoot toad, Scaphiopus couchii, exhibits thirst-related behavior in the form of cutaneous drinking. This behavior has been termed water absorption response (WR) behavior. Spadefoot toads live in harsh desert environments and are subject annually to dehydrating conditions that may induce thirst-related behavior. We tested the hypothesis that an increase in WR behavior is associated with both an increase in plasma osmolality and an increase in plasma and brain angiotensin concentrations. First, we determined the degree of dehydration that was necessary to initiate WR behavior. Animals dehydrated to 85% of their standard bladder-empty weight via deprivation of water exhibited WR behavior more frequently than control toads left in home containers with water available. Next, using the same dehydration methods, we determined the plasma osmolality and sodium concentrations of dehydrated toads. Toads dehydrated to 85% standard weight also had a significant increase in plasma osmolality, but exhibited no overall change in plasma sodium concentrations, indicating that while an overall increase in plasma osmolality appears to be associated with WR behavior in S. couchii, changes in sodium concentrations alone are not sufficient to induce the behavior. Finally, plasma and brain angiotensin concentrations were measured in control toads and toads dehydrated to 85% standard weight. Plasma and brain angiotensin concentrations did not increase in dehydrated toads, indicating that dehydration-induced WR behavior that is associated with changes in plasma osmolality may not be induced by changes in endogenous angiotensin concentrations in S. couchii.

Determination of boldine in plasma by high-performance liquid chromatography.

PubMed

Speisky, H; Cassels, B K; Nieto, S; Valenzuela, A; Nuñez-Vergara, L J

1993-02-26

A sensitive method for the determination of boldine in blood plasma is described. The procedure involves a direct pH-buffered chloroform extraction of boldine from blood plasma, followed by its assay under isocratic conditions by HPLC with UV detection. The extraction recovery is excellent, and sensitivity and precision of the method are very high, when applied to plasma samples containing pharmacologically relevant concentrations of boldine.

Simple equation for calculation of plasma clearance for evaluation of renal function without urine collection in rats.

PubMed

Liu, Xiang; Peng, Dejun; Tian, Hao; Lu, Chengyu

2017-01-01

To develop an equation for the evaluation of renal function in rats using three dilutions of plasma samples and to validate this method by comparison with a reference method. The investigation was conducted in Sprague-Dawley (SD) rats after delivery of three doses of iohexol, with blood samples collected before and after dosage using a quantitative blood collection method. Plasma iohexol concentrations were detected by high performance liquid chromatography (HPLC). The extraction recovery of iohexol from plasma was >97.30% and the calibration curve was linear (r 2  = 0.9997) over iohexol concentrations ranging from 10 to 1000 µg/mL. The method had an RE of <9.310 and intra- and inter-day RSD of <5.137% and <3.693%, respectively. The plasma clearance values obtained from the equation correlated closely (r = 0.763) with those obtained using the reference method. The relatively correlation in the results obtained using the method under investigation and the reference method indicate that this new equation can be used for preliminary assessment of renal function in rats. © 2016 Asian Pacific Society of Nephrology.

Evaluation of plasma antioxidant activity in rats given excess EGCg with reference to endogenous antioxidants concentrations and assay methods.

PubMed

Yokotani, Kaori; Umegaki, Keizo

2017-02-01

The contribution of (-)-epigallocatechin gallate (EGCg) intake to in vivo antioxidant activity is unclear, even with respect to plasma. In this study, we examined how administration of EGCg contributes to plasma antioxidant activity, relative to its concentration, endogenous antioxidants, and assay methods, namely oxygen radical absorbance capacity (ORAC) and ferric reducing/antioxidant power (FRAP). Administration of EGCg (500 mg/kg) to rats increased plasma EGCg (4μmol/L as free form) and ascorbic acid (1.7-fold), as well as ORAC (1.2-fold) and FRAP (3-fold) values. The increase in plasma ascorbic acid following EGCg administration was accompanied by its relocation from the adrenal glands and lymphocytes into plasma, and was related to the increase in FRAP. Plasma deproteinization and assays in plasma model solutions revealed that protein levels significantly contributed to ORAC values, where <3 μmol/L EGCg in the presence of protein exhibited minimal antioxidant activity, as measured by both FRAP and ORAC. As the concentration of plasma ascorbic acid was not influenced by deproteinization, differences in FRAP values with and without deproteinization were estimated to determine the contribution of enhanced ascorbic acid attributable to EGCg administration. These results will help to understand the points that should be considered when evaluating EGCg antioxidant activity in plasma.

[Pharmacokinetics of magnolol and honokiol in Weichang'an pill].

PubMed

Chen, Yu-Ling; Wang, Shu-Ping; Wang, Lei; Jin, Zhao-Xiang; Zhang, Jing-Ze; Chen, Hong; Gao, Wen-Yuan

2016-05-01

To conduct multiple-reaction monitoring(MRM) quantitative analysis with high-performance liquid chromatography coupled with mass spectrometry method, establish the quantification method of magnolol and honokiol in blood sample under negative ion mode with ibuprofen as internal standard, investigate the pharmacokinetic process of lignans constituents after oral administration of Weichang'an pill(WCA) at different doses, and provide theoretical basis to further reveal the material basis of WCA's anti-diarrhea effect. In the plasma samples, the linear relationship was good over the concentration range of 5.25 to 1 344.00 μg•L ⁻¹ for magnolol and 10.08 to 2 580.00 μg•L ⁻¹ for honokiol. The results of precision, stability, and extraction recovery tests showed that the determination method of plasma concentration for such compositions was stable and reliable. Dose-dependence was shown for magnolol and honokiol in the plasma concentration-time profile. The results indicated that the time to reach the maximum plasma concentration(Tmax) for lignanoids was 0.55-1.42 h, when the maximum plasma concentration(Cmax) could reach 996.36-2 330.96,189.87-1 469.43 μg•L ⁻¹ respectively for magnolol and honokiol. The lignanoids could be absorbed rapidly in the blood after oral administration of WAC pills, providing experimental basis to prove rapid and long-acting anti-diarrhea effect of WAC pills after oral administration. Copyright© by the Chinese Pharmaceutical Association.

Measurement of rivaroxaban and apixaban in serum samples of patients

PubMed Central

Harenberg, Job; Krämer, Sandra; Du, Shanshan; Zolfaghari, Shabnam; Schulze, Astrid; Krämer, Roland; Weiss, Christel; Wehling, Martin; Lip, Gregory Y H

2014-01-01

Background The determination of rivaroxaban and apixaban from serum samples of patients may be beneficial in specific clinical situations when additional blood sampling for plasma and thus the determination of factor Xa activity is not feasible or results are not plausible. Materials and methods The primary aim of this study was to compare the concentrations of rivaroxaban and apixaban in serum with those measured in plasma. Secondary aims were the performance of three different chromogenic methods and concentrations in patients on treatment with rivaroxaban 10 mg od (n = 124) or 20 mg od (n = 94) or apixaban 5 mg bid (n = 52) measured at different time. Results Concentrations of rivaroxaban and apixaban in serum were about 20–25% higher compared with plasma samples with a high correlation (r = 0·79775–0·94662) using all assays (all P < 0·0001). The intraclass correlation coefficients were about 0·90 for rivaroxaban and 0·55 for apixaban. Mean rivaroxaban concentrations were higher at 2 and 3 h compared with 1 and 12 h after administration measured from plasma and serum samples (all P-values < 0·05) and were not different between 1 vs. 12 h (plasma and serum). Conclusions The results indicate that rivaroxaban and apixaban concentrations can be determined specifically from serum samples. PMID:24931429

Total plasma magnesium in healthy and critically ill foals.

PubMed

Mariella, J; Isani, G; Andreani, G; Freccero, F; Carpenè, E; Castagnetti, C

2016-01-15

Abnormalities in total Mg (tMg) concentration in plasma and/or serum are common in critically ill humans, and the association with increased mortality has been documented in several clinical studies in adults and newborns with hypoxic-ischemic encephalopathy. Abnormalities in tMg were studied in hospitalized dogs, cats, and adult horses. Newborn foals were scarcely studied with regard to Mg concentration. The aims of the present study were: (1) to compare two analytical methods for the determination of tMg in plasma: the automated colorimetric method and the atomic absorption spectrometry; (2) to measure plasma tMg in healthy foals during the first 72 hours after birth and in sick foals during the first 72 hours of hospitalization; (3) to compare total plasma Mg concentration among healthy foals, foals affected by perinatal asphyxia syndrome (PAS), prematurity and/or dismaturity, and sepsis; (4) to evaluate tMg plasma concentration in surviving and non-surviving foals. One hundred seventeen foals were included in the study: 20 healthy and 97 sick foals. The automated method used in clinical practice probably overestimates plasma tMg. Due to its higher sensitivity and specificity, the atomic absorption spectrometry should be considered the method of choice from an analytical point of view, but requires an instrumentation not easily available in any laboratory and specific technical skills and competencies. Plasma tMg in healthy foals were included in the range 0.52 to 1.01 mmol/L and did not show any time-dependent change during the first 72 hours of life. In sick foals, tMg evaluated at T0 was statistically higher than tMg measured at subsequent times. Foals affected by PAS had a tMg at T0 significantly higher (P < 0.01) than healthy, septic, and premature and/or dysmature foals. The t test found significantly higher (P < 0.01) plasma tMg measured at T0 in non-surviving than in surviving foals. Plasma tMg could be a useful parameter for the diagnosis of PAS and the formulation of the prognosis in critically ill foals. Copyright © 2016 Elsevier Inc. All rights reserved.

Measurement of concentrations of whole blood levels of choline, betaine, and dimethylglycine and their relations to plasma levels.

PubMed

Awwad, Hussain Mohamad; Kirsch, Susanne H; Geisel, Juergen; Obeid, Rima

2014-04-15

We aimed at developing a method for the measurement of choline and its metabolites in whole blood (WB). After an extraction step, quantification of choline, betaine, and dimethylglycine (DMG) was performed using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Plasma and WB metabolites were evaluated in a group of 61 elderly people. The calibration curves were linear (r(2)>0.997) for all compounds. The inter- and intra-assay coefficients of variation for all analytes were <10%. The recoveries were >90% and the relative matrix effect were ≤4.0%. The median concentrations of choline, betaine, and DMG were 11.3, 27.8, and 5.9μmol/L in plasma and 66.6, 165, and 13.7μmol/L in WB, respectively. There were positive correlations between WB and plasma markers; for choline (r=0.42), betaine (r=0.61), and DMG (r=0.56) (all p≤0.001). The concentrations of betaine in WB and plasma were significantly higher in men than in women. The concentrations of WB choline and DMG did not differ significantly according to sex. In conclusion, we have established a reliable method for measuring choline metabolites in WB. The concentrations of WB choline, betaine, and DMG seem to reflect intracellular concentrations of these metabolites. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantification of ethanol in plasma by electrochemical detection with an unmodified screen printed carbon electrode

NASA Astrophysics Data System (ADS)

Tian, Gang; Zhang, Xiao-Qing; Zhu, Ming-Song; Zhang, Zhong; Shi, Zheng-Hu; Ding, Min

2016-03-01

Simple, rapid and accurate detection of ethanol concentration in blood is very crucial in the diagnosis and management of potential acute ethanol intoxication patients. A novel electrochemical detection method was developed for the quantification of ethanol in human plasma with disposable unmodified screen-printed carbon electrode (SPCE) without sample preparation procedure. Ethanol was detected indirectly by the reaction product of ethanol dehydrogenase (ADH) and cofactor nicotinamide adenine dinucleotide (NAD+). Method validation indicated good quantitation precisions with intra-day and inter-day relative standard deviations of ≤9.4% and 8.0%, respectively. Ethanol concentration in plasma is linear ranging from 0.10 to 3.20 mg/mL, and the detection limit is 40.0 μg/mL (S/N > 3). The method shows satisfactory correlation with the reference method of headspace gas chromatography in twenty human plasma samples (correlation coefficient 0.9311). The proposed method could be applied to diagnose acute ethanol toxicity or ethanol-related death.

Quantification of ethanol in plasma by electrochemical detection with an unmodified screen printed carbon electrode

PubMed Central

Tian, Gang; Zhang, Xiao-Qing; Zhu, Ming-Song; Zhang, Zhong; Shi, Zheng-Hu; Ding, Min

2016-01-01

Simple, rapid and accurate detection of ethanol concentration in blood is very crucial in the diagnosis and management of potential acute ethanol intoxication patients. A novel electrochemical detection method was developed for the quantification of ethanol in human plasma with disposable unmodified screen-printed carbon electrode (SPCE) without sample preparation procedure. Ethanol was detected indirectly by the reaction product of ethanol dehydrogenase (ADH) and cofactor nicotinamide adenine dinucleotide (NAD+). Method validation indicated good quantitation precisions with intra-day and inter-day relative standard deviations of ≤9.4% and 8.0%, respectively. Ethanol concentration in plasma is linear ranging from 0.10 to 3.20 mg/mL, and the detection limit is 40.0 μg/mL (S/N > 3). The method shows satisfactory correlation with the reference method of headspace gas chromatography in twenty human plasma samples (correlation coefficient 0.9311). The proposed method could be applied to diagnose acute ethanol toxicity or ethanol-related death. PMID:27006081

EXTENDED STORAGE OF BUFFY-COAT PLATELET CONCENTRATES IN PLASMA OR A PLATELET ADDITIVE SOLUTION

PubMed Central

Slichter, Sherrill J.; Bolgiano, Doug; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Bailey, S. Lawrence; Pellham, Esther

2014-01-01

Background Platelet concentrates prepared from whole blood in the U.S. are made using the platelet-rich-plasma (PRP) method. The platelet concentrates must be made within 8 hours of blood collection and stored for only 5 days. In Europe and Canada, platelet concentrates are made using the buffy-coat (BC) method from whole blood held overnight at 22°C and storage times may be up to 7 days. Our studies were designed to determine how long BC platelets can be stored in plasma or Plasmalyte while meeting the FDA’s post-storage viability criteria. Study Design, Materials, And Methods Normal subjects donated whole blood that was stored at 22°C for 22 ± 2 hours prior to preparation of BC platelets. Platelets were stored for 5 to 8 days in either plasma or Plasmalyte concentrations of 65% or 80%. Radiolabeled autologous stored versus fresh platelet recoveries and survivals were assessed as well as post-storage in vitro assays. Results BC platelets stored in either plasma or 65% Plasmalyte met FDA post-storage platelet recovery criteria for 7 days but survivals for only 6 days, while storage in 80% Plasmalyte gave very poor results. Both stored platelet recoveries and survivals correlated with the same donor’s fresh results, but the correlation was much stronger between recoveries than survivals. In vitro measures of extent of shape change, morphology score, and pH best predicted post-storage platelet recoveries, while annexin V binding best predicted platelet survivals. Conclusion BC platelets stored in either plasma or 65% Plasmalyte meet FDA’s post-storage viability criteria for 6 days. PMID:24673482

Determination of Efavirenz in Human Dried Blood Spots by Reversed-Phase High Performance Liquid Chromatography with UV Detection

PubMed Central

Hoffman, Justin T; Rossi, Steven S; Espina-Quinto, Rowena; Letendre, Scott; Capparelli, Edmund V

2013-01-01

Background Previously published methods for determination of efavirenz (EFV) in human dried blood spots (DBS) employ costly and complex liquid chromatography/mass spectrometry. We describe the validation and evaluation of a simple and inexpensive high-performance liquid chromatography (HPLC) method for EFV quantification in human DBS and dried plasma spots (DPS), using ultraviolet (UV) detection appropriate for resource-limited settings. Methods 100μl of heparinized whole blood or plasma were spotted onto blood collection cards, dried, punched, and eluted. Eluates are injected onto a C-18 reversed phase HPLC column. EFV is separated isocratically using a potassium phosphate and ACN mobile phase. UV detection is at 245nm. Quantitation is by use of external calibration standards. Following validation, the method was evaluated using whole blood and plasma from HIV-positive patients undergoing EFV therapy. Results Mean recovery of drug from dried blood spots is 91.5%. The method is linear over the validated concentration range of 0.3125 – 20.0μg/mL. A good correlation (Spearman r=0.96) between paired plasma and DBS EFV concentrations from the clinical samples was observed, and hematocrit level was not found to be a significant determinant of the EFV DBS level. The mean observed CDBS/Cplasma ratio was 0.68. A good correlation (Spearman r=0.96) between paired plasma and DPS EFV concentrations from the clinical samples was observed. The mean percent deviation of DPS samples from plasma samples is 1.68%. Conclusions Dried whole blood spot or dried plasma spot sampling is well suited for monitoring EFV therapy in resource limited settings, particularly when high sensitivity is not essential. PMID:23503446

Rapid measurement of plasma free fatty acid concentration and isotopic enrichment using LC/MS

PubMed Central

Persson, Xuan-Mai T.; Błachnio-Zabielska, Agnieszka Urszula; Jensen, Michael D.

2010-01-01

Measurements of plasma free fatty acids (FFA) concentration and isotopic enrichment are commonly used to evaluate FFA metabolism. Until now, gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) was the best method to measure isotopic enrichment in the methyl derivatives of 13C-labeled fatty acids. Although IRMS is excellent for analyzing enrichment, it requires time-consuming derivatization steps and is not optimal for measuring FFA concentrations. We developed a new, rapid, and reliable method for simultaneous quantification of 13C-labeled fatty acids in plasma using high-performance liquid chromatography-mass spectrometry (HPLC/MS). This method involves a very quick Dole extraction procedure and direct injection of the samples on the HPLC system. After chromatographic separation, the samples are directed to the mass spectrometer for electrospray ionization (ESI) and analysis in the negative mode using single ion monitoring. By employing equipment with two columns connected parallel to a mass spectrometer, we can double the throughput to the mass spectrometer, reducing the analysis time per sample to 5 min. Palmitate flux measured using this approach agreed well with the GC/C/IRMS method. This HPLC/MS method provides accurate and precise measures of FFA concentration and enrichment. PMID:20526002

Determination of efavirenz in human dried blood spots by reversed-phase high-performance liquid chromatography with UV detection.

PubMed

Hoffman, Justin T; Rossi, Steven S; Espina-Quinto, Rowena; Letendre, Scott; Capparelli, Edmund V

2013-04-01

Previously published methods for determination of efavirenz (EFV) in human dried blood spots (DBS) use costly and complex liquid chromatography/mass spectrometry. We describe the validation and evaluation of a simple and inexpensive high-performance liquid chromatography method for EFV quantification in human DBS and dried plasma spots (DPS), using ultraviolet detection appropriate for resource-limited settings. One hundred microliters of heparinized whole blood or plasma were spotted onto blood collection cards, dried, punched, and eluted. Eluates are injected onto a C-18 reversed phase high-performance liquid chromatography column. EFV is separated isocratically using a potassium phosphate and acetonitrile mobile phase. Ultraviolet detection is at 245 nm. Quantitation is by use of external calibration standards. Following validation, the method was evaluated using whole blood and plasma from HIV-positive patients undergoing EFV therapy. Mean recovery of drug from DBS is 91.5%. The method is linear over the validated concentration range of 0.3125-20.0 μg/mL. A good correlation (Spearman r = 0.96) between paired plasma and DBS EFV concentrations from the clinical samples was observed, and hematocrit level was not found to be a significant determinant of the EFV DBS level. The mean observed C DBS/C plasma ratio was 0.68. A good correlation (Spearman r = 0.96) between paired plasma and DPS EFV concentrations from the clinical samples was observed. The mean percent deviation of DPS samples from plasma samples is 1.68%. Dried whole blood spot or dried plasma spot sampling is well suited for monitoring EFV therapy in resource-limited settings, particularly when high sensitivity is not essential.

Plasma N-Terminal Pro B-Type Natriuretic Peptide Concentrations in Dogs with Pulmonic Stenosis

PubMed Central

KOBAYASHI, Keiya; HORI, Yasutomo; CHIMURA, Syuuichi

2014-01-01

ABSTRACT The detailed information between plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations and dogs with pulmonic stenosis (PS) is still unknown. The aim of the present study was to investigate the clinical utility of measuring plasma NT-proBNP concentrations in dogs with PS and to determine whether plasma NT-proBNP concentration could be used to assess disease severity. This retrospective study enrolled 30 client-owned, untreated dogs with PS (asymptomatic [n=23] and symptomatic [n=7]) and 11 healthy laboratory beagles. Results of physical examination, thoracic radiography and echocardiography were recorded. Plasma NT-proBNP concentrations were measured using commercial laboratories. Compared to the healthy control dogs, cardiothoracic ratio was significantly increased in dogs with both asymptomatic and symptomatic PS. Similarly, the ratio of the main pulmonary artery to aorta was significantly decreased in dogs with both asymptomatic and symptomatic PS. The pulmonic pressure gradient in the symptomatic PS dogs was significantly higher than that in the asymptomatic PS dogs. Plasma NT-proBNP concentration was significantly elevated in the symptomatic PS dogs compared to the healthy control dogs and the asymptomatic PS dogs. Furthermore, the Doppler-derived pulmonic pressure gradient was significantly correlated with the plasma NT-proBNP concentration (r=0.78, r2=0.61, P<0.0001). Plasma NT-proBNP concentration >764 pmol/l to identify severe PS had a sensitivity of 76.2% and specificity of 81.8%. The plasma NT-proBNP concentration increased by spontaneous PS, i.e. right-sided pressure overload and can be used as an additional method to assess the severity of PS in dogs. PMID:24561377

Plasma N-terminal pro B-type natriuretic peptide concentrations in dogs with pulmonic stenosis.

PubMed

Kobayashi, Keiya; Hori, Yasutomo; Chimura, Syuuichi

2014-06-01

The detailed information between plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations and dogs with pulmonic stenosis (PS) is still unknown. The aim of the present study was to investigate the clinical utility of measuring plasma NT-proBNP concentrations in dogs with PS and to determine whether plasma NT-proBNP concentration could be used to assess disease severity. This retrospective study enrolled 30 client-owned, untreated dogs with PS (asymptomatic [n=23] and symptomatic [n=7]) and 11 healthy laboratory beagles. Results of physical examination, thoracic radiography and echocardiography were recorded. Plasma NT-proBNP concentrations were measured using commercial laboratories. Compared to the healthy control dogs, cardiothoracic ratio was significantly increased in dogs with both asymptomatic and symptomatic PS. Similarly, the ratio of the main pulmonary artery to aorta was significantly decreased in dogs with both asymptomatic and symptomatic PS. The pulmonic pressure gradient in the symptomatic PS dogs was significantly higher than that in the asymptomatic PS dogs. Plasma NT-proBNP concentration was significantly elevated in the symptomatic PS dogs compared to the healthy control dogs and the asymptomatic PS dogs. Furthermore, the Doppler-derived pulmonic pressure gradient was significantly correlated with the plasma NT-proBNP concentration (r=0.78, r(2)=0.61, P<0.0001). Plasma NT-proBNP concentration >764 pmol/l to identify severe PS had a sensitivity of 76.2% and specificity of 81.8%. The plasma NT-proBNP concentration increased by spontaneous PS, i.e. right-sided pressure overload and can be used as an additional method to assess the severity of PS in dogs.

The relationship between the daily dose, the plasma concentration of blonanserin, and its plasma anti-dopamine D2 and anti-serotonin 5-HT2A activity.

PubMed

Suzuki, Hidenobu; Gen, Keishi

2010-01-01

Blonanserin (BNS) possesses anti-serotonin 5-HT(2A) activity in addition to anti-dopamine D(2) activity, which is characteristic of second-generation antipsychotics, little information is available on its pharmacologic profile in vivo. We investigated the BNS daily dose, plasma concentration, plasma anti-D(2) activity, and plasma anti-5-HT(2A) activity in schizophrenia in a total of 14 subjects. Blood samples were taken 14 days after the BNS dose was fixed, and the plasma concentration was measured by means of high-performance liquid chromatographic (HPLC) method. In addition, the plasma anti-D(2) activity and anti-5-HT(2A) activity were measured by means of radioreceptor assays in which [(3)H]-spiperone and [(3)H]-ketanserin were used. The results revealed a statistically significant correlation between the daily dose and the plasma concentration (p = 0.04). Statistically significant correlations were also observed between the plasma concentration and the anti-D(2) activity and between the plasma concentration and the anti-5-HT(2A) activity (p = 0.003 and 0.04). It is therefore believed that both the anti-D(2) activity in plasma and the anti-5-HT(2A) activity in plasma are regulated almost solely by the unchanged principal. Moreover, the mean plasma serotonin/dopamine (S/D) ratio was 0.9 and BNS exhibited both anti-D(2) activity and also anti-5-HT(2A) activity in vivo, as well, so it was clear that the in vitro pharmacological profile was retained in vivo.

Etravirine in CSF is highly protein bound

PubMed Central

Nguyen, Anh; Rossi, Steven; Croteau, David; Best, Brookie M.; Clifford, David; Collier, Ann C.; Gelman, Benjamin; Marra, Christina; McArthur, Justin; McCutchan, J. Allen; Morgello, Susan; Simpson, David; Ellis, Ronald J.; Grant, Igor; Capparelli, Edmund; Letendre, Scott; Ellis, Ronald J.; Letendre, Scott; Abramson, Ian; Al-Lozi, Muhammad; Atkinson, J. Hampton; Capparelli, Edmund; Clifford, David; Collier, Ann C.; Fennema-Notestine, Christine; Gamst, Anthony C.; Gelman, Benjamin; Heaton, Robert K.; Marcotte, Thomas D.; Marra, Christina; McCutchan, J. Allen; McArthur, Justin; Morgello, Susan; Simpson, David; Smith, Davey M.; Taylor, Michael J.; Theilmann, Rebecca; Vaida, Florin; Paul Woods, Steven; Cushman, Clint; Dawson, Matthew; Franklin, Donald; Jones, Trudy; Lewis, Kristen; Mintz, Letty; Teshome, Mengesha; Toperoff, Will

2013-01-01

Objectives Etravirine has high affinity for plasma drug-binding proteins, such as albumin and α1-acid glycoprotein, which limits the amount of unbound etravirine available to enter the CNS. The objective of this study was to compare total and unbound etravirine concentrations in CSF with plasma concentrations and the in vitro median inhibitory concentration (IC50) for wild-type HIV (0.9 ng/mL). Methods Total and bound etravirine concentrations were measured in 17 CSF and plasma pairs by isotope-dilution liquid chromatography tandem mass spectroscopy, radioligand displacement and ultracentrifugation. Unbound etravirine concentrations were calculated from the bound fraction. The dynamic range of the assay was 7.8–2000 (plasma) and 0.78–200 (CSF) ng/mL. Results Subjects were mostly middle-aged (median 43 years) white (78%) men (89%). All CSF etravirine concentrations were above the limit of quantification. Total and unbound median etravirine concentrations in CSF were 9.5 (IQR 6.4, 26.4) and 0.13 (IQR 0.08, 0.27) ng/mL, respectively. Etravirine was 96% (IQR 94.5, 97.2) protein bound in plasma and 98.4% (IQR 97.8, 98.8) in CSF. Total etravirine in CSF was 4.3% (IQR 3, 5.9) of total and 101% (IQR 76, 160) of unbound etravirine in plasma. There were no significant correlations between unbound etravirine concentrations and concentrations of albumin in plasma or CSF. Unbound etravirine concentrations in CSF did not reach the wild-type IC50 in any of the specimens. Conclusions Unbound etravirine may not achieve optimal concentrations to inhibit HIV replication in the CNS. PMID:23335197

Spectroscopic investigations of microwave generated plasmas

NASA Technical Reports Server (NTRS)

Hawley, Martin C.; Haraburda, Scott S.; Dinkel, Duane W.

1991-01-01

The study deals with the plasma behavior as applied to spacecraft propulsion from the perspective of obtaining better design and modeling capabilities. The general theory of spectroscopy is reviewed, and existing methods for converting emission-line intensities into such quantities as temperatures and densities are outlined. Attention is focused on the single-atomic-line and two-line radiance ratio methods, atomic Boltzmann plot, and species concentration. Electronic temperatures for a helium plasma are determined as a function of pressure and a gas-flow rate using these methods, and the concentrations of ions and electrons are predicted from the Saha-Eggert equations using the sets of temperatures obtained as a function of the gas-flow rate. It is observed that the atomic Boltzmann method produces more reliable results for the electronic temperature, while the results obtained from the single-line method reflect the electron temperatures accurately.

Increased plasma proline concentrations are associated with sarcopenia in the elderly

PubMed Central

Adachi, Yusuke; Imaizumi, Akira; Hakamada, Tomomi; Abe, Yasuko; Kaneko, Eiji; Takahashi, Soiciro; Shimokado, Kentaro

2017-01-01

Background and purpose Metabolome analyses have shown that plasma amino acid profiles reflect various pathological conditions, such as cancer and diabetes mellitus. It remains unclear, however, whether plasma amino acid profiles change in patients with sarcopenia. This study therefore aimed to investigate whether sarcopenia-specific changes occur in plasma amino acid profiles. Methods A total of 153 community-dwelling and seven institutionalized elderly individuals (56 men, 104 women; mean age, 77.7±7.0 years) were recruited for this cross-sectional analysis. We performed a comprehensive geriatric assessment, which included an evaluation of hand grip strength, gait speed, muscle mass and blood chemistry, including the concentration of 18 amino acids. Results Twenty-eight of the 160 participants met the criteria for sarcopenia established by the Asian Working Group on Sarcopenia in Older People. Univariate analysis revealed associations between the presence of sarcopenia and a higher plasma concentration of proline and glutamine, lower concentrations of histidine and tryptophan. Multivariable analysis revealed that a higher concentration of proline was the only variable independently associated with sarcopenia. Conclusions The plasma concentration of proline may be useful for understanding the underlying pathophysiology of sarcopenia. PMID:28934309

Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory - Determination of Elements in Whole-Water Digests Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry

USGS Publications Warehouse

Garbarino, John R.; Struzeski, Tedmund M.

1998-01-01

Inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) can be used to determine 26 elements in whole-water digests. Both methods have distinct advantages and disadvantages--ICP-OES is capable of analyzing samples with higher elemental concentrations without dilution, however, ICP-MS is more sensitive and capable of determining much lower elemental concentrations. Both techniques gave accurate results for spike recoveries, digested standard reference-water samples, and whole-water digests. Average spike recoveries in whole-water digests were 100 plus/minus 10 percent, although recoveries for digests with high dissolved-solid concentrations were lower for selected elements by ICP-MS. Results for standard reference-water samples were generally within 1 standard deviation of hte most probable values. Statistical analysis of the results from 43 whole-water digest indicated that there was no significant difference among ICP-OES, ICP-MS, and former official methods of analysis for 24 of the 26 elements evaluated.

Investigating Uranium Concentrations in Groundwaters in the State of Idaho Using Kinetic Phosphorescence Analysis and Inductively Coupled Plasma Mass Spectrometry.

PubMed

Tkavadze, Levan; Dunker, Roy E; Brey, Richard R; Dudgeon, John

2016-11-01

The determination of uranium concentrations in natural water samples is of great interest due to the environmental consequences of this radionuclide. In this study, 380 groundwater samples from various locations within the state of Idaho were analyzed using two different techniques. The first method was Kinetic Phosphorescence Analysis (KPA), which gives the total uranium concentrations in water samples. The second analysis method was inductively coupled plasma mass spectrometry (ICP- MS). This method determines the total uranium concentration as well as the separate isotope concentrations of uranium. The U/U isotopic ratio was also measured for each sample to confirm that there was no depleted or enriched uranium present. The results were compared and mapped separately from each other. The study also found that in some areas of the state, natural uranium concentrations are relatively high.

Large inter-individual variation in isoflavone plasma concentration limits use of isoflavone intake data for risk assessment

PubMed Central

van der Velpen, V; Hollman, P C; van Nielen, M; Schouten, E G; Mensink, M; van't Veer, P; Geelen, A

2014-01-01

Background/objectives: Isoflavones are present in soy foods and soy-based supplements. Despite low plasma isoflavone concentrations in the general Western population, concentrations in supplement users exceed those suggested to be beneficial for health in Asian populations, raising concerns for adverse effects. To aid risk assessment, quantification of the relation between isoflavone intake and plasma concentrations is essential. Subjects/methods: Plasma samples were collected from postmenopausal women in three placebo-controlled crossover studies with 8-week periods for supplements (two studies, ~100 mg isoflavones/day, n=88) or 4-week periods for soy foods (one study, ~48 mg isoflavones/day, n=15). Plasma isoflavone concentrations (daidzein, equol, genistein and glycitein) were quantified using high-performance liquid chromatography and electrochemical detection. The association between plasma concentrations and isoflavone intake, equol producer status, intake–producer interaction and background dietary intake was assessed based on the assumption of a log-linear relation. Results: Median plasma total isoflavone concentrations after the soy food and supplement interventions were respectively 2.16 and 3.47 μmol/l for equol producers and 1.30 and 2.39 μmol/l for non-producers. Regression analysis showed that doubling isoflavone intake increased plasma concentrations by 55–62% (±s.e. 1–2%, R2>0.87) for daidzein, genistein, equol (only for producers) and total isoflavones; for glycitein the association was weaker (15±1%, R2=0.48). Adjustments for energy, carbohydrate and fat intake did not affect these estimates. Inter-individual variation, estimated based on repeated measures in one of the studies, was 30–96%. Conclusions: Although the relation between isoflavone intake and plasma concentrations was adequately quantified, the use of isoflavone intake data for risk assessment needs caution due to large inter-individual variation in plasma concentrations. PMID:24939433

Can Saliva and Plasma Methadone Concentrations Be Used for Enantioselective Pharmacokinetic and Pharmacodynamic Studies in Patients With Advanced Cancer?

PubMed

George, Rani; Haywood, Alison; Good, Phillip; Hennig, Stefanie; Khan, Sohil; Norris, Ross; Hardy, Janet

2017-09-01

Methadone is a potent analgesic used to treat refractory cancer pain. It is administered as a racemic mixture, with the l-enantiomer being primarily a μ-receptor agonist, whereas the d-enantiomer is an N-methyl-d-aspartate antagonist and inhibits serotonin and norepinephrine reuptake. Dose requirements vary greatly among patients to achieve optimal pain control and to avoid the risk of adverse effects. The relationship between plasma and saliva methadone enantiomer concentrations was investigated to determine if saliva could be a substitute for plasma in pharmacodynamic and pharmacokinetic studies for clinical monitoring and dose optimization of methadone in patients with advanced cancer. Patients with advanced cancer who were prescribed varying doses of oral methadone for pain management were recruited to obtain paired plasma and saliva samples. Pain scores were recorded at the time of sampling. The total and unbound plasma and saliva concentrations of the l- and d-enantiomers of methadone were quantified by using an HPLC-MS/MS method. The relationship between plasma (total and unbound) and saliva concentrations were compared. The saliva-to-plasma concentration ratio was compared versus the dose administered and the time after dosing for both enantiomers. The association of methadone concentrations with reported pain scores was compared by using a Mann-Whitney U test for significance. Fifty patients receiving a mean dose of 11mg/d of methadone provided 151 paired plasma and saliva samples. The median age of the population was 61 years with an interquartile range of 53-71 years with total body weight ranging from 59-88 kg. Median (interquartile) total plasma concentrations for l- and d-methadone were 50.78 ng/mL (30.6-113.0 ng/mL) and 62.0 ng/mL (28.7-116.0 ng/mL), respectively. Median (interquartile range) saliva concentrations for l- and d-methadone were 81.5 ng/mL (28.0-203.2 ng/mL) and 44.2 (16.2-149.7 ng/mL). No relationship could be established between plasma and saliva concentrations for l- and d-methadone (r 2 = 0.35 and 0.25). The saliva-to-plasma concentration analyzed with the methadone dose showed higher saliva concentrations at lower doses. Dose-normalized saliva concentrations followed a similar pattern over time compared with plasma concentrations. No correlation was found between l-methadone plasma, d-methadone plasma, l-methadone saliva, d-methadone saliva concentrations, and pain score. Saliva concentration was not a better predictor of pain control than plasma concentration for dose optimization and monitoring studies of methadone in patients with cancer. Although the saliva-to-plasma ratio of the concentration of methadone enantiomers was stable across the dosing range, due to the variability in individual saliva-to-plasma ratios, saliva sampling may not be a valid substitute in pharmacokinetic studies of methadone in cancer. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Comparison of the Immulite and RIA assay methods for measuring peripheral blood progesterone levels in Greyhound bitches.

PubMed

Chapwanya, A; Clegg, T; Stanley, P; Vaughan, L

2008-09-15

Determination of optimal breeding time in bitches earmarked for single insemination only is based on measurement of peripheral blood serum or plasma progesterone concentration. In this paper a comparison is made between radioimmune assay (RIA) and chemoluminescent assay (Immulite) for determination of P4 concentrations in the bitch. The Immulite assay is shown to be an accurate and reliable method for serum or plasma P4 measurement. It compares favourably with other methods in terms of turn-around time, cost and accessibility for veterinarians in practice.

Flow-injection chemiluminescence determination of melamine in urine and plasma.

PubMed

Tang, Xiaoshuang; Shi, Xiyan; Tang, Yuhai; Yue, Zhongjin; He, Qiqi

2012-01-01

A novel flow-injection chemiluminescence method for the determination of melamine in urine and plasma was developed. It was found that melamine can remarkably enhance chemiluminescence emission from the luminol-K(3) Fe(CN)(6) system in an alkaline medium. Under the optimum conditions, chemiluminescence intensity had a good linear relationship with the concentration of melamine in the range 9.0 × 10(-9) -7.0 × 10(-6) g/mL, with a correlation coefficient of 0.9992. The detection limit (3σ) was 3.5 ng/mL. The method has been applied to determine the concentration of melamine in samples using liquid-liquid extraction. Average recoveries of melamine were 102.6% in urine samples and 95.1% in plasma samples. The method provided a reproducible and stable approach for the sensitive detection of melamine in urine and plasma samples. Copyright © 2011 John Wiley & Sons, Ltd.

Simultaneous determination of glucose, triglycerides, urea, cholesterol, albumin and total protein in human plasma by Fourier transform infrared spectroscopy: direct clinical biochemistry without reagents.

PubMed

Jessen, Torben E; Höskuldsson, Agnar T; Bjerrum, Poul J; Verder, Henrik; Sørensen, Lars; Bratholm, Palle S; Christensen, Bo; Jensen, Lene S; Jensen, Maria A B

2014-09-01

Direct measurement of chemical constituents in complex biologic matrices without the use of analyte specific reagents could be a step forward toward the simplification of clinical biochemistry. Problems related to reagents such as production errors, improper handling, and lot-to-lot variations would be eliminated as well as errors occurring during assay execution. We describe and validate a reagent free method for direct measurement of six analytes in human plasma based on Fourier-transform infrared spectroscopy (FTIR). Blood plasma is analyzed without any sample preparation. FTIR spectrum of the raw plasma is recorded in a sampling cuvette specially designed for measurement of aqueous solutions. For each analyte, a mathematical calibration process is performed by a stepwise selection of wavelengths giving the optimal least-squares correlation between the measured FTIR signal and the analyte concentration measured by conventional clinical reference methods. The developed calibration algorithms are subsequently evaluated for their capability to predict the concentration of the six analytes in blinded patient samples. The correlation between the six FTIR methods and corresponding reference methods were 0.87

Assay of calcium borogluconate veterinary medicines for calcium gluconate, boric acid, phosphorus, and magnesium by using inductively coupled plasma emission spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyons, D.J.; Spann, K.P.

1985-03-01

An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are +/- 1.4% (calcium), +/- 1.8% (boron), +/- 2.6% (phosphorus), and +/- 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.

Cloud-point extraction is compatible with liquid chromatography coupled to electrospray ionization mass spectrometry for the determination of antazoline in human plasma.

PubMed

Giebułtowicz, Joanna; Kojro, Grzegorz; Piotrowski, Roman; Kułakowski, Piotr; Wroczyński, Piotr

2016-09-05

Cloud-point extraction (CPE) is attracting increasing interest in a number of analytical fields, including bioanalysis, as it provides a simple, safe and environmentally-friendly sample preparation technique. However, there are only few reports on the application of this extraction technique in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. In this study, CPE was used for the isolation of antazoline from human plasma. To date, only one method of antazoline isolation from plasma exists-liquid-liquid extraction (LLE). The aim of this study was to prove the compatibility of CPE and LC-ESI-MS/MS and the applicability of CPE to the determination of antazoline in spiked human plasma and clinical samples. Antazoline was isolated from human plasma using Triton X-114 as a surfactant. Xylometazoline was used as an internal standard. NaOH concentration, temperature and Triton X-114 concentration were optimized. The absolute matrix effect was carefully investigated. All validation experiments met international acceptance criteria and no significant relative matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples. The determination of antazoline concentration in human plasma in the range 10-2500ngmL(-1) by the CPE method led to results which are equivalent to those obtained by the widely used liquid-liquid extraction method. Copyright © 2016 Elsevier B.V. All rights reserved.

Analytical methods involving separation techniques for determination of low-molecular-weight biothiols in human plasma and blood.

PubMed

Isokawa, Muneki; Kanamori, Takahiro; Funatsu, Takashi; Tsunoda, Makoto

2014-08-01

Low-molecular-weight biothiols such as homocysteine, cysteine, and glutathione are metabolites of the sulfur cycle and play important roles in biological processes such as the antioxidant defense network, methionine cycle, and protein synthesis. Thiol concentrations in human plasma and blood are related to diseases such as cardiovascular disease, neurodegenerative disease, and cancer. The concentrations of homocysteine, cysteine, and glutathione in plasma samples from healthy human subjects are approximately in the range of 5-15, 200-300, and 1-5 μM, respectively. Glutathione concentration in the whole blood is in the millimolar range. Measurement of biothiol levels in plasma and blood is thought to be important for understanding the physiological roles and biomarkers for certain diseases. This review summarizes the relationship of biothiols with certain disease as well as pre-analytical treatment and analytical methods for determination of biothiols in human plasma and blood by using high-performance liquid chromatography and capillary electrophoresis coupled with ultraviolet, fluorescence, or chemiluminescence detection; or mass spectrometry. Copyright © 2014 Elsevier B.V. All rights reserved.

Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luong, Elise

1999-05-10

This dissertation focuses on the development of methods for stable isotope metabolic tracer studies in living systems using inductively coupled plasma single and dual quadrupole mass spectrometers. Sub-nanogram per gram levels of molybdenum (Mo) from human blood plasma are isolated by the use of anion exchange alumina microcolumns. Million-fold more concentrated spectral and matrix interferences such as sodium, chloride, sulfate, phosphate, etc. in the blood constituents are removed from the analyte. The recovery of Mo from the alumina column is 82 ± 5% (n = 5). Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is utilized for the quantitative ultra-tracemore » concentration determination of Mo in bovine and human blood samples. The average Mo concentration in reference bovine serum determined by this method is 10.2 ± 0.4 ng/g, while the certified value is 11.5 ± 1.1 ng/g (95% confidence interval). The Mo concentration of one pool of human blood plasma from two healthy male donors is 0.5 ± 0.1 ng/g. The inductively coupled plasma twin quadrupole mass spectrometer (ICP-TQMS) is used to measure the carbon isotope ratio from non-volatile organic compounds and bio-organic molecules to assess the ability as an alternative analytical method to gas chromatography combustion isotope ratio mass spectrometry (GC-combustion-IRMS). Trytophan, myoglobin, and β-cyclodextrin are chosen for the study, initial observation of spectral interference of 13C + with 12C 1H + comes from the incomplete dissociation of myoglobin and/or β-cyclodextrin.« less

An ultra-high pressure liquid chromatography-tandem mass spectrometry method for the quantification of teicoplanin in plasma of neonates.

PubMed

Begou, O; Kontou, A; Raikos, N; Sarafidis, K; Roilides, E; Papadoyannis, I N; Gika, H G

2017-03-15

The development and validation of an ultra-high pressure liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) method was performed with the aim to be applied for the quantification of plasma teicoplanin concentrations in neonates. Pharmacokinetic data of teicoplanin in the neonatal population is very limited, therefore, a sensitive and reliable method for the determination of all isoforms of teicoplanin applied in a low volume of sample is of real importance. Teicoplanin main components were extracted by a simple acetonitrile precipitation step and analysed on a C18 chromatographic column by a triple quadrupole MS with electrospray ionization. The method provides quantitative data over a linear range of 25-6400ng/mL with LOD 8.5ng/mL and LOQ 25ng/mL for total teicoplanin. The method was applied in plasma samples from neonates to support pharmacokinetic data and proved to be a reliable and fast method for the quantification of teicoplanin concentration levels in plasma of infants during therapy in Intensive Care Unit. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of a brass alloy concentration composition using calibration-free laser-induced breakdown spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Achouri, M.; Baba-Hamed, T.; Beldjilali, S. A., E-mail: sidahmed.beldjilali@univ-usto.dz

2015-09-15

Laser-induced breakdown spectroscopy (LIBS) is a technique that can provide qualitative and quantitative measurements of the characteristics of irradiated metals. In the present work, we have calculated the parameters of the plasma produced from a brass alloy sample under the action of a pulsed Nd: YAG laser operating at 1064 nm. The emission lines of copper atoms (Cu I), zinc atoms (Zn I), and lead atoms (Pb I), which are elements of a brass alloy composition, were used to investigate the parameters of the brass plasma. The spectral profiles of Cu, Zn, and Pb lines have been used to extractmore » the electron temperature and density of the brass alloy plasma. The characteristics of Cu, Zn, and Pb were determined quantatively by the calibration-free LIBS (CF-LIBS) method considering for accurate analysis that the laser-induced ablated plasma is optically thin in local thermodynamic equilibrium conditions and the plasma ablation is stoichiometric. The Boltzmann plot method was used to evaluate the plasma temperature, and the Stark broadened profiles were used to determine the electron density. An algorithm based on the experimentally measured values of the intensity of spectral lines and the basic laws of plasma physics was developed for the determination of Cu, Zn, and Pb concentrations in the brass sample. The concentrations C{sub CF-LIBS} calculated by CF-LIBS and the certified concentrations C{sub certified} were very close.« less

Paracetamol plasma and cerebrospinal fluid pharmacokinetics in children

PubMed Central

Anderson, B J; Holford, N H G; Woollard, G A; Chan, P L S

1998-01-01

Aims Paracetamol has a central action for both antipyresis and analgesia. Maximum temperature decrease and peak analgesia are reported at 1–2 h after peak plasma paracetamol concentration. We wished to determine the relationship between plasma and cerebrospinal fluid (CSF) pharmacokinetics in children. Methods Concentration-time profiles in plasma and CSF after nasogastric paracetamol 40 mg kg−1 were measured in nine children who had indwelling ventricular drains. Estimation of population pharmacokinetic parameters was made using both a standard two-stage population approach (MKMODEL) and a nonlinear mixed effect model (NONMEM). Results were standardized to a 70 kg person using an allometric power model. Results Both approaches gave similar estimates. NONMEM parameter estimates were clearance 10.2 l h−1 (CV 47%), volume of distribution 67.1 l (CV 58%) and absorption rate constant 0.77 h−1 (CV 49%). Cerebrospinal fluid concentrations lagged behind those of plasma. The equilibration half time was 0.72 h (CV 117%). The CSF/plasma partition coefficient was 1.18 (CV 8%). Conclusions Higher concentrations in the CSF probably reflect the lower free water volume of plasma. The CSF equilibration half time suggests that CSF kinetics approximate more closely to the effect compartment than plasma, but further time is required for paracetamol to exert its effects. Effect site concentrations equilibrate slowly with plasma. Paracetamol should be given 1–2 h before anticipated pain or fever in children. PMID:9764964

Method for determining the concentration of atomic species in gases and solids

DOEpatents

Loge, Gary W.

1999-01-01

Method for determining the concentration of atomic species in gases and solids. Measurement of at least two emission intensities from a species in a plasma containing the species after a sufficient time period has elapsed after the generation of the plasma and during a second time period, permits an instantaneous temperature to be established within the sample. The concentration of the atomic species to be determined is then derived from the known emission intensity of a predetermined concentration of that species in the sample at the measured temperature, a quantity which is measured prior to the determination of the unknown concentration, and the actual measured emission from the unknown species, or by this latter emission and the emission intensity of a species having known concentration within the sample.

Rapid and sensitive method for determination of withaferin-A in human plasma by HPLC.

PubMed

Patial, Pankaj; Gota, Vikram

2011-02-01

To develop and validate a rapid and sensitive high-performance liquid chromatographic method for determination of withaferin-A in human plasma. Withaferin-A, the active molecule of a traditional Indian herb, has demonstrated several biological activities in preclinical models. A validated bioassay is not available for its pharmacokinetic evaluation. The chromatographic system used a reverse-phase C18 column with UV-visible detection at 225 nm. The mobile phase consisted of water and acetonitrile applied in a gradient flow. Withaferin-A was extracted by simple protein-precipitation technique. The calibration curve was linear in the concentration range of 0.05-1.6 µg/ml. The method has the desired sensitivity to detect the plasma concentration range of withaferin-A that is likely to show biological activity based on in vitro data. This is the first HPLC method ever described for the estimation of withaferin-A in human plasma which could be applied for pharmacokinetic studies.

Liver plasma membranes: an effective method to analyze membrane proteome.

PubMed

Cao, Rui; Liang, Songping

2012-01-01

Plasma membrane proteins are critical for the maintenance of biological systems and represent important targets for the treatment of disease. The hydrophobicity and low abundance of plasma membrane proteins make them difficult to analyze. The protocols given here are the efficient isolation/digestion procedures for liver plasma membrane proteomic analysis. Both protocol for the isolation of plasma membranes and protocol for the in-gel digestion of gel-embedded plasma membrane proteins are presented. The later method allows the use of a high detergent concentration to achieve efficient solubilization of hydrophobic plasma membrane proteins while avoiding interference with the subsequent LC-MS/MS analysis.

Comparison of direct sampling and brochoalveolar lavage for determining active drug concentrations in the pulmonary epithelial lining fluid of calves injected with enrofloxacin or tilmicosin.

PubMed

Foster, D M; Sylvester, H J; Papich, M G

2017-12-01

Antibiotic distribution to interstitial fluid (ISF) and pulmonary epithelial fluid (PELF) was measured and compared to plasma drug concentrations in eight healthy calves. Enrofloxacin (Baytril ® 100) was administered at a dose of 12.5 mg/kg subcutaneously (SC), and tilmicosin (Micotil ® 300) was administered at a dose of 20 mg/kg SC. PELF, sampled by two different methods-bronchoalveolar lavage (BAL) and direct sampling (DS)-plasma, and ISF were collected from each calf and measured for tilmicosin, enrofloxacin and its metabolite ciprofloxacin by HPLC. Pharmacokinetic analysis was performed on the concentrations in each fluid, for each drug. The enrofloxacin/ciprofloxacin concentration as measured by AUC in DS samples was 137 ± 72% higher than in plasma, but in BAL samples, this value was 535 ± 403% (p < .05). The concentrations of tilmicosin in DS and BAL samples exceeded plasma drug concentrations by 567 ± 189% and 776 ± 1138%, respectively. The enrofloxacin/ciprofloxacin concentrations collected by DS were significantly different than those collected by BAL, but the tilmicosin concentrations were not significantly different between the two methods. Concentrations of enrofloxacin/ciprofloxacin exceeded the MIC values for bovine respiratory disease pathogens but tilmicosin did not reach MIC levels for these pathogens in any fluids. © 2017 John Wiley & Sons Ltd.

Simple and validated UHPLC-MS/MS analysis of nimodipine in plasma and cerebrospinal fluid of patients with subarachnoid haemorrhage.

PubMed

Mohamed, Susan; Riva, Roberto; Contin, Manuela

2016-08-15

We present a simple, fast and validated method for the determination of nimodipine in plasma and cerebrospinal fluid (CSF) of patients with subarachnoid haemorrhage using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Plasma or CSF 250μL aliquots were pretreated with acetonitrile spiked with lacosamide as internal standard. The chromatographic separation was performed on a Fusion (3μm) 50×2.0mm I.D. column with gradient elution of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile at a flow rate of 0.35mL/min. The MS/MS ion transitions were 419.1→343 for nimodipine and 251.1→91 for the internal standard. The linearity was determined from 2.0 to 40.0ng/mL in plasma and 40.0-800.0pg/mL in CSF. The lower limit of quantitation (LLOQ) of nimodipine was 0.4ng/mL in plasma and 40pg/mL in CSF. The mean recovery for nimodipine was ≥75% in plasma and ≥90% in CSF at all three considered concentrations. Intra- and interassay precision and accuracy were ≤15% at all quality control concentrations in plasma and CSF. The method was applied to measure plasma and CSF concentrations of nimodipine in a series of patients with subarachnoid haemorrhage treated with intravenous nimodipine. The present procedure, omitting time-consuming liquid-liquid extraction and drying steps, is faster, simpler and cheaper than published LC-MS/MS analytical methods for nimodipine in plasma and the first validated one for nimodipine in CSF. Copyright © 2016 Elsevier B.V. All rights reserved.

Raltegravir Cerebrospinal Fluid Concentrations in HIV-1 Infection

PubMed Central

Yilmaz, Aylin; Gisslén, Magnus; Spudich, Serena; Lee, Evelyn; Jayewardene, Anura; Aweeka, Francesca; Price, Richard W.

2009-01-01

Introduction Raltegravir is an HIV-1 integrase inhibitor currently used in treatment-experienced HIV-1-infected patients resistant to other drug classes. In order to assess its central nervous system penetration, we measured raltegravir concentrations in cerebrospinal fluid (CSF) and plasma in subjects receiving antiretroviral treatment regimens containing this drug. Methods Raltegravir concentrations were determined by liquid chromatography tandem mass spectrometry in 25 paired CSF and plasma samples from 16 HIV-1-infected individuals. The lower limit of quantitation was 2.0 ng/ml for CSF and 10 ng/ml for plasma. Results Twenty-four of the 25 CSF samples had detectable raltegravir concentrations with a median raltegravir concentration of 18.4 ng/ml (range, <2.0–126.0). The median plasma raltegravir concentration was 448 ng/ml (range, 37–5180). CSF raltegravir concentrations correlated with CSF:plasma albumin ratios and CSF albumin concentrations. Conclusions Approximately 50% of the CSF specimens exceeded the IC95 levels reported to inhibit HIV-1 strains without resistance to integrase inhibitors. In addition to contributing to control of systemic HIV-1 infection, raltegravir achieves local inhibitory concentrations in CSF in most, but not all, patients. Blood-brain and blood-CSF barriers likely restrict drug entry, while enhanced permeability of these barriers enhances drug entry. PMID:19721718

The determination of fenspiride in human plasma and urine by liquid chromatography with electrochemical or ultraviolet detection.

PubMed

Sauveur, C; Baune, A; Vergnes, N; Jeanniot, J P

1989-01-01

A selective and sensitive method for the determination of fenspiride in biological fluids is described. The method involves liquid-liquid extraction followed by separation on a reversed-phase column with electrochemical detection for low levels of the drug in plasma (less than or equal to 100 ng ml-1) or UV absorption for higher concentrations in plasma or urine. The method is suitable for pharmacokinetic analyses and drug monitoring studies.

Molecular mechanism of plasma sterilization in solution with the reduced pH method: importance of permeation of HOO radicals into the cell membrane

NASA Astrophysics Data System (ADS)

Takai, Eisuke; Ikawa, Satoshi; Kitano, Katsuhisa; Kuwabara, Junpei; Shiraki, Kentaro

2013-07-01

Sterilization of certain infected areas of the human body surface is necessary for dental and surgical therapies. Because the blood is filled with body fluid, sterilization in solution is essential. In vitro solution sterilization has been successively carried out using a combination of low-temperature atmospheric-pressure plasma and the reduced pH method, where the solution is sufficiently acidic. Here, we show the molecular mechanism of such plasma sterilization in solution based on microbiology. Three kinds of bacteria were inactivated by plasma treatment under various pH conditions. The theoretical and experimental models revealed that the sterilization was characterized by the concentration of hydroperoxy radicals (HOO·), which were dependent on the pH value. Bacterial inactivation rates were proportional to the HOO· concentrations calculated by the theoretical model. To evaluate the penetration of radicals into the cell membrane, a bacterial model using dye-included micelles was used. Decolouration rates of the model were also in proportion with the calculated HOO· concentrations. These results indicate that the key species for plasma sterilization were hydroperoxy radicals. More importantly, the high permeation of hydroperoxy radicals into the cell membrane plays a key role for efficient bactericidal inactivation using the reduced pH method.

Rapid measurement of fibrinogen concentration in whole blood using a steel ball coagulometer

PubMed Central

Schlimp, Christoph J.; Khadem, Anna; Klotz, Anton; Solomon, Cristina; Hochleitner, Gerald; Ponschab, Martin; Redl, Heinz; Schöchl, Herbert

2015-01-01

BACKGROUND Fibrinogen plays a key role in hemostasis and is the first coagulation factor to reach critical levels in bleeding patients. Current European guidelines on the management of traumatic or perioperative bleeding recommend fibrinogen supplementation at specific threshold levels. Whole blood viscoelastic tests provide fast evaluation of fibrin deficits. Fast measurement of plasma fibrinogen concentration is not yet available. We investigated a method to rapidly determine whole blood fibrinogen concentration using standard Clauss assays and a steel ball coagulometer and provide an estimate of the “plasma-equivalent” fibrinogen concentration within minutes by adjustment of the measured whole blood fibrinogen concentration with a quickly measureable hemoglobin-derived hematocrit. METHODS The feasibility of this approach was tested with a Clauss assay using multiple porcine fresh blood samples obtained during in vivo bleeding, hemodilution, and after treatment with hemostatic therapy. Two different Clauss assays were then tested using multiple human volunteers’ blood samples diluted in vitro and supplemented with fibrinogen concentrate. Comparative measurements with fibrin-based thromboelastometry tests were performed. RESULTS Regression and Bland-Altman analyses of derived “plasma-equivalent” fibrinogen and measured plasma fibrinogen concentration was excellent in porcine and human blood samples, especially in the ranges relevant to traumatic or perioperative bleeding. CONCLUSION Fast whole blood fibrinogen measurements could be considered as an alternative to plasma fibrinogen measurement for acute bleeding management in trauma and perioperative care settings. Further studies are needed to prove this concept and determine the turnaround times for its clinical application in emergency departments and operating theaters. PMID:25742256

Experimental Study on Inactivation of Bacterial Endotoxin by Using Dielectric Barrier Discharge

NASA Astrophysics Data System (ADS)

Shi, Xingmin; Li, Yaxi; Zhang, Guanjun; Ma, Yue; Shao, Xianjun

2011-12-01

The low-temperature plasma (LTP) generated by dielectric barrier discharge (DBD) was used to sterilize the E.coli endotoxin, which is usually difficult to kill by traditional methods. Three different concentrations of bacterial endotoxin (1 EU/mL, 0.5 EU/mL and 0.25 EU/mL) were treated by LTP for different time (20 s, 40 s and 60 s). Tachypleus amebocyte lysate (TAL) method was employed to detect the concentration variation of bacterial endotoxin before and after the plasma treatment, and endotoxic shock mice model was used to evaluate the inactivation effects of LTP on endotoxin for further study. Experimental results demonstrated that, DBD plasma can inactivate the bacterial endotoxin quickly and effectively, and when the LTP treatment time was increased, the concentrations of bacterial endotoxin decreased gradually (after 60 s plasma treatment, its inactivation effect was beyond the Chinese pharmacopoeia standard), and the average survival time of mice gradually extended. The possible inactivation mechanisms are proposed to be related to reactive oxygen species (ROSs).

A generic standard additions based method to determine endogenous analyte concentrations by immunoassays to overcome complex biological matrix interference.

PubMed

Pang, Susan; Cowen, Simon

2017-12-13

We describe a novel generic method to derive the unknown endogenous concentrations of analyte within complex biological matrices (e.g. serum or plasma) based upon the relationship between the immunoassay signal response of a biological test sample spiked with known analyte concentrations and the log transformed estimated total concentration. If the estimated total analyte concentration is correct, a portion of the sigmoid on a log-log plot is very close to linear, allowing the unknown endogenous concentration to be estimated using a numerical method. This approach obviates conventional relative quantification using an internal standard curve and need for calibrant diluent, and takes into account the individual matrix interference on the immunoassay by spiking the test sample itself. This technique is based on standard additions for chemical analytes. Unknown endogenous analyte concentrations within even 2-fold diluted human plasma may be determined reliably using as few as four reaction wells.

Non-esterified fatty acids in early luteal bovine oviduct fluid mirror plasma concentrations: An ex vivo approach.

PubMed

Jordaens, Lies; Van Hoeck, Veerle; De Bie, Jessie; Berth, Mario; Marei, Waleed F A; Desmet, Karolien L J; Bols, Peter E J; Leroy, Jo L M R

2017-09-01

We investigated whether and to which extent plasma non-esterified fatty acids (NEFAs) are reflected in oviduct fluid (OF) using an improved ex vivo flushing method. OF and plasma NEFA concentrations were respectively 0.29±0.19 and 0.31±0.14mmol/L, they didn't differ significantly (P=0.13) and tended to be positively correlated (Pearson correlation coefficient=0.56; P=0.07). Results suggest that OF NEFAs mirror the concentrations seen in plasma of healthy cattle. Copyright © 2017 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

A validated UPLC-MS/MS method for the analysis of linezolid and a novel oxazolidinone derivative (PH027) in plasma and its application to tissue distribution study in rabbits.

PubMed

Hedaya, Mohsen A; Thomas, Vidhya; Abdel-Hamid, Mohamed E; Kehinde, Elijah O; Phillips, Oludotun A

2017-01-01

Linezolid is the first approved oxazolidinone antibacterial agent, whereas PH027 is a novel compound of the same class that exhibits good in vitro antibacterial activity. The objective of this study was to develop an UPLC-MS/MS assay for the analysis of linezolid and PH027 in plasma and to apply the method for comparative pharmacokinetic and tissue distribution studies of both compounds. Plasma samples and calibrators were extracted with diethyl ether after addition of the internal standard solution. After evaporation of the ether layer, the residue was reconstituted in mobile phase and injected into UPLC-MS/MS. The mobile phase consisted of 2mM ammonium acetate buffer solution and acetonitrile (70:30) at a flow rate of 0.2ml/min. Separation was achieved using UPLC BEH C 18 column, and quantitative determination of the analytes was performed using multiple-reaction monitoring (MRM) scanning mode. The method was validated by analyzing quality control tissue homogenate samples, and was applied to analyze tissue homogenate samples obtained following IV injections of linezolid and PH027 in rabbits. The developed UPLC-MS/MS method was linear in the concentration range of 50-5000ng/ml. Validation of the method proved that the method's precision, selectivity and stability were all within the acceptable limits. Linezolid and PH027 concentrations were accurately determined in the quality control tissue homogenate samples, and analysis of samples obtained following IV administration of the two compounds showed that the tissue to plasma concentration ratio of PH027 was higher than that of linezolid probably due to its higher lipophilicity. The developed UPLC-MS/MS method for the analysis of linezolid and PH027 in rabbit's plasma can accurately determine the concentrations of these compounds in different tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of five methods for determination of total plasma protein concentration.

PubMed

Okutucu, Burcu; Dinçer, Ayşşe; Habib, Omer; Zihnioglu, Figen

2007-08-01

Quantitation of exact total protein content is often a key step and is common to many applications in general biochemistry research and routine clinical laboratory practice. Before embarking on any type of protein analysis, particularly comparative techniques, it is important to accurately quantitate the amount of protein in the sample. In order to assess the quality of total protein estimation results, five methods were tested and were applied to the same pooled plasma sample. For this aim, Bradford (Coomassie Brilliant Blue), Lowry (Folin-Ciocalteau), Biüret, Pesce and Strande (Ponceau-S/TCA), and modified method of Schaffner-Weismann (Amido Black 10B) were used. The last two methods employ simultaneous precipitation of proteins with the acid containing dye solutions followed by dissolution of precipitate in a NaOH solution. It is shown that each assay has advantages and disadvantages relative to sensitivity, ease of performance, acceptance in literature, accuracy and reproducibility/coefficient of variation. All of the methods tested show a CV %<6. Besides pooled plasma, a known concentration of human serum albumin was also analyzed and discussed by means of standardization of plasma total protein content.

A novel method for the quantitation of gingerol glucuronides in human plasma or urine based on stable isotope dilution assays.

PubMed

Schoenknecht, Carola; Andersen, Gaby; Schieberle, Peter

2016-11-15

The bio-active compounds of ginger (Zingiber officinale Roscoe), the gingerols, are gaining considerable attention due to their numerous beneficial health effects. In order to elucidate the physiological relevance of the ascribed effects their bioavailability has to be determined taking their metabolization into account. To quantitate in vivo generated [6]-, [8]- and [10]-gingerol glucuronides in human plasma and urine after ginger tea consumption, a simultaneous and direct liquid chromatography-tandem mass spectrometry method based on stable isotope dilution assays was established and validated. The respective references as well as the isotopically labeled substances were synthesized and characterized by mass spectrometry and NMR. Selective isolation of gingerol glucuronides from human plasma and urine by a mixed-phase anion-exchange SPE method led to recovery rates between 80.8 and 98.2%. LC-MS/MS analyses in selected reaction monitoring modus enabled a highly sensitive quantitation of gingerol glucuronides with LoQs between 3.9-9.8nmol/L in plasma and 39.3-161.1nmol/L in urine. The method precision in plasma and urine varied in the range±15%, whereas the intra-day accuracy in plasma and urine showed values between 78 and 122%. The developed method was then applied to a pilot study in which two volunteers consumed one liter ginger tea. Pharmacokinetic parameters like the maximum concentration (c max ), the time to reach c max (t max ), area under the curve (AUC), elimination rate constant (k el ) and elimination half-life (t 1/2 ) were calculated from the concentration-time curve of each gingerol glucuronide. The obtained results will enable more detailed investigation of gingerol glucuronides as bioactives in their physiologically relevant concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

Chloride inhibition of nitrite uptake for non-teleost Actinopterygiian fishes.

PubMed

Boudreaux, Perry J; Ferrara, Allyse M; Fontenot, Quenton C

2007-06-01

Fish that transport environmental chloride with a gill uptake mechanism (gill epithelial Cl(-)/HCO(3)(-)cotransport exchange system), also transport nitrite into plasma through the same mechanism. Because of the relationship between nitrite uptake and the gill chloride uptake mechanism, nitrite uptake can provide insight regarding the method of chloride uptake for fish. This study was designed to determine if non-teleost fishes concentrate nitrite in their plasma, and to determine if chloride inhibits nitrite uptake in non-teleost fish. To determine if bowfin Amia calva, spotted gar Lepisosteus oculatus, alligator gar Atractosteus spatula, and paddlefish Polyodon spathula concentrate environmental nitrite in their plasma, individuals were exposed to concentrations of 0, 1, 10, or 100 mg/L nitrite-N. After exposure, all species had plasma nitrite-N concentrations greater than environmental levels. To determine if chloride inhibits nitrite uptake for spotted gar, alligator gar, and paddlefish, fish were exposed to 1 mg/L nitrite-N and 20 mg/L chloride as calcium chloride, or to 1 mg/L nitrite-N only. Chloride effectively prevented nitrite from being concentrated in the plasma of all species. It appears that non-teleost fish concentrate nitrite in their plasma via their chloride uptake mechanism and that this is an ancestral characteristic for teleost.

Comparison of digoxin concentration in plastic serum tubes with clot activator and heparinized plasma tubes

PubMed Central

Dukić, Lora; Šimundić, Ana-Maria; Malogorski, Davorin

2014-01-01

Introduction: Sample type recommended by the manufacturer for the digoxin Abbott assay is either serum collected in glass tubes or plasma (sodium heparin, lithium heparin, citrate, EDTA or oxalate as anticoagulant) collected in plastic tubes. In our hospital samples are collected in plastic tubes. Our hypothesis was that the serum sample collected in plastic serum tube can be used interchangeably with plasma sample for measurement of digoxin concentration. Our aim was verification of plastic serum tubes for determination of digoxin concentration. Materials and methods: Concentration of digoxin was determined simultaneously in 26 venous blood plasma (plastic Vacuette, LH Lithium heparin) and serum (plastic Vacuette, Z Serum Clot activator; both Greiner Bio-One GmbH, Kremsmünster, Austria) samples, on Abbott AxSYM analyzer using the original Abbott Digoxin III assay (Abbott, Wiesbaden, Germany). Tube comparability was assessed using the Passing Bablok regression and Bland-Altman plot. Results: Serum and plasma digoxin concentrations are comparable. Passing Bablok intercept (0.08 [95% CI = −0.10 to 0.20]) and slope (0.99 [95% CI = 0.92 to 1.11]) showed there is no constant or proportional error. Conclusion: Blood samples drawn in plastic serum tubes and plastic plasma tubes can be interchangeably used for determination of digoxin concentration. PMID:24627723

Ammonia concentrations in canine whole blood, EDTA-anticoagulated whole blood, and plasma measured by use of a point-of-care ammonia meter.

PubMed

Odunayo, Adesola; Tobias, Karen M; Okafor, Chika C; Flatland, Bente

2017-11-01

OBJECTIVE To investigate the use of canine whole blood (WB) for measurement of ammonia concentration by use of a point-of-care ammonia meter and to compare results of measuring ammonia concentrations in WB, EDTA-anticoagulated WB, and plasma. ANIMALS 40 client-owned dogs. PROCEDURES A blood sample (2 mL) was obtained from each dog. One drop of WB was immediately applied to a test strip for evaluation with an ammonia meter. The remainder of the blood sample was placed in an EDTA-containing tube, and 1 drop of EDTA-anticoagulated WB was applied to a test strip. The remaining EDTA-anticoagulated WB sample was centrifuged, and the plasma was harvested and placed on ice. One drop of plasma was applied to a test strip; the remainder of the plasma sample was transported on ice and used for ammonia measurement with a reference laboratory instrument. All samples were tested within 1 hour after sample collection. Results were evaluated to detect significant differences in ammonia concentration. RESULTS Ammonia concentrations did not differ significantly between WB and EDTA-anticoagulated WB and between plasma samples measured with the meter and reference laboratory instrument. However, median ammonia concentration was significantly higher in plasma than in WB or EDTA-anti-coagulated WB. CONCLUSIONS AND CLINICAL RELEVANCE Anticoagulant-free WB was a valid sample for measurement by use of the ammonia meter. Plasma samples had higher ammonia concentrations than did WB samples. Results for each sample type should be interpreted by use of specimen- and method-specific reference intervals.

Association between body weight and composition and plasma 25-hydroxyvitamin D level in the Diabetes Prevention Program

PubMed Central

CEGLIA, LISA; NELSON, JASON; WARE, JAMES; ALYSANDRATOS, KONSTANTINOS-DIONYSIOS; BRAY, GEORGE A.; GARGANTA, CHERYL; NATHAN, DAVID M.; HU, FRANK B; DAWSON-HUGHES, BESS; PITTAS, ANASTASSIOS G.

2016-01-01

Objective We examined associations between body weight and plasma 25-hydroxyvitamin D concentration (25OHD) in pre-diabetes and sought to estimate the impact of adiposity on these associations. Methods The study was conducted in the placebo (n=1,082) and intensive lifestyle (n=1,079) groups of the Diabetes Prevention Program (DPP), a multicenter trial to prevent type 2 diabetes in adults with pre-diabetes. Weight and 25OHD were measured at baseline, month 6, years 1 and 2. In a subset (n=584), visceral [VAT] and subcutaneous [SAT] adiposity were assessed by computed tomography at baseline and year 1. Results In cross-sectional analyses, baseline body weight, total fat, VAT, and SAT were inversely associated with plasma 25OHD concentration after multivariable adjustment. VAT accounted for 40% [95% CI 11, 69] of the association of body weight with plasma 25OHD concentration. There was no significant contribution by total fat or SAT. Two-year changes in plasma 25OHD concentration varied inversely with changes in body weight (p<0.0001). One-year changes in total fat, VAT, or SAT were not significant mediators of the association between change in plasma 25OHD concentration and body weight. Conclusion Our study found an inverse association between body weight and plasma 25OHD concentration at baseline and over a 2-year period in adults with pre-diabetes. These findings in the DPP, a weight loss intervention study, raise the possibility that weight loss increases plasma 25OHD concentration. Whether adiposity mediates this association remains inconclusive. PMID:26525562

Decreased plasma concentrations of brain-derived neurotrophic factor (BDNF) in patients with functional hypothalamic amenorrhea.

PubMed

Podfigurna-Stopa, Agnieszka; Casarosa, Elena; Luisi, Michele; Czyzyk, Adam; Meczekalski, Blazej; Genazzani, Andrea Riccardo

2013-09-01

Functional hypothalamic amenorrhea (FHA) is a non organic, secondary amenorrhea related to gonadotropin-releasing hormone pulsatile secretion impairment. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family of survival-promoting molecules, plays an important role in the growth, development, maintenance and function of several neuronal systems. The aim of the study was the evaluation of plasma BDNF concentrations in patients with the diagnosis of FHA. We studied 85 subjects diagnosed with FHA who were compared with 10 healthy, eumenorrheic controls with normal body mass index. Plasma BDNF and serum luteinizing hormone, follicle-stimulating hormone and estradiol (E2) concentrations were measured by immunoenzymatic method (enzyme-linked immunosorbent assay). Significantly lower concentration of plasma BDNF was found in FHA patients (196.31 ± 35.26 pg/ml) in comparison to healthy controls (407.20 ± 25.71 pg/ml; p < 0.0001). In the control group, there was a strong positive correlation between plasma BDNF and serum E2 concentrations (r = 0.92, p = 0.0001) but in FHA group it was not found. Role of BDNF in FHA is not yet fully understood. There could be found studies concerning plasma BDNF concentrations in humans and animals in the literature. However, our study is one of the first projects which describes decreased plasma BDNF concentration in patients with diagnosed FHA. Therefore, further studies on BDNF in FHA should clarify the role of this peptide.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reid, A.A.; Fleming, P.J.; Lake, C.R.

We modified a norepinephrine radioenzymatic method for determination of plasma phenylpropanolamine (PPA) concentrations. PPA is converted to N(methyl-/sup 3/H)ephedrine ((/sup 3/H)EPD) by the enzyme phenylethanolamine N-methyltransferase (PNMT) and S-(methyl-/sup 3/H)adenosyl-L-methionine ((/sup 3/H)AdoMet). The product, (/sup 3/H)EPD, is isolated from unreacted (/sup 3/H)AdoMet and labeled side products by an organic extraction and a TLC procedure. In addition, a preincubation organic extraction procedure is included to remove inhibitors of PNMT from plasma and to concentrate the sample for enhanced enzymatic conversion. In order to accurately quantitate PPA across the wide range of possible concentrations, the assay is conducted at two plasma volumes.more » PPA concentrations between 0.3 and 50 micrograms/liter can be detected with 1 ml of plasma, while concentrations between 4 and 1500 micrograms/liter can be detected with 0.1 ml of plasma. The intra-assay coefficients of variation (CVs) are 9.3 and 5.7% at 0.5 and 1500 micrograms/liter, respectively, while the mean interassay CV is 13.8%.« less

Dietary, anthropometric, and biochemical factors influencing plasma choline, carnitine, trimethylamine, and trimethylamine-N-oxide concentrations.

PubMed

Malinowska, Anna M; Szwengiel, Artur; Chmurzynska, Agata

2017-06-01

The objective of the study was to evaluate the nutritional, anthropometric, and biochemical factors that influence choline, l-carnitine, trimethylamine (TMA), and trimethylamine-N-oxide (TMAO) metabolism in elderly women. The volunteers' diet was assessed using a food frequency questionnaire. Dietary patterns were estimated using a self-established score method. Body mass index (BMI), serum glucose, total, HDL, LDL cholesterol, triacylglycerol, homocysteine (tHcy), free choline (fchol), L-carnitine, TMA, and TMAO were assessed. Higher concentrations of l-carnitine, fchol, and TMAO were found in those women who had more western-style dietary patterns. Nor choline or betaine intake affected plasma fchol, TMA, or TMAO. BMI was positively correlated with fchol and TMA. tHcy was positively correlated with fchol, TMA, and TMAO, while fchol was also positively correlated with TMA and TMAO. Dietary patterns and plasma tHcy concentration influence fchol, TMA, and TMAO plasma concentration. Plasma TMA and fchol may be associated with BMI.

Plasma concentrations and intakes of amino acids in male meat-eaters, fish-eaters, vegetarians and vegans: a cross-sectional analysis in the EPIC-Oxford cohort

PubMed Central

Schmidt, J A; Rinaldi, S; Scalbert, A; Ferrari, P; Achaintre, D; Gunter, M J; Appleby, P N; Key, T J; Travis, R C

2016-01-01

Background/Objectives: We aimed to investigate the differences in plasma concentrations and in intakes of amino acids between male meat-eaters, fish-eaters, vegetarians and vegans in the Oxford arm of the European Prospective Investigation into Cancer and Nutrition. Subjects/Methods: This cross-sectional analysis included 392 men, aged 30–49 years. Plasma amino acid concentrations were measured with a targeted metabolomic approach using mass spectrometry, and dietary intake was assessed using a food frequency questionnaire. Differences between diet groups in mean plasma concentrations and intakes of amino acids were examined using analysis of variance, controlling for potential confounding factors and multiple testing. Results: In plasma, concentrations of 6 out of 21 amino acids varied significantly by diet group, with differences of −13% to +16% between meat-eaters and vegans. Concentrations of methionine, tryptophan and tyrosine were highest in fish-eaters and vegetarians, followed by meat-eaters, and lowest in vegans. A broadly similar pattern was seen for lysine, whereas alanine concentration was highest in fish-eaters and lowest in meat-eaters. For glycine, vegans had the highest concentration and meat-eaters the lowest. Intakes of all 18 dietary amino acids differed by diet group; for the majority of these, intake was highest in meat-eaters followed by fish-eaters, then vegetarians and lowest in vegans (up to 47% lower than in meat-eaters). Conclusions: Men belonging to different habitual diet groups have significantly different plasma concentrations of lysine, methionine, tryptophan, alanine, glycine and tyrosine. However, the differences in plasma concentrations were less marked than and did not necessarily mirror those seen for amino acid intakes. PMID:26395436

A simple LC-MS/MS method for determination of deferasirox in human plasma: Troubleshooting of interference from ferric ion in method development and its application.

PubMed

Li, Tengfei; Cui, Zhimin; Wang, Yan; Yang, Wen; Li, Duo; Song, QinXin; Sun, Luning; Ding, Li

2018-03-20

As an orally active iron chelator, deferasirox forms its ion complexes in the prepared plasma samples and LC-MS mobile phase where ferric ion exists, and then comparing with the nominal concentration level, a lower detected concentration level of deferasirox would be obtained after LC-MS analysis, if no proper treatment was adopted. Meanwhile, the phenomenon would be observed that multiple repeat injections of the same deferasirox plasma sample in the same tube would show the lower and lower detected concentration levels of deferasirox, which caused by more and more ferric ions from the injection needle dissolved in the sample solution as multiple repeated injections. The addition of a proper concentration of EDTA in the mobile phase and the sample will competitively inhibit deferasirox from complexing with ferric ion, and prevent the decrease of deferasirox concentration. In this paper, an LC-MS/MS method was developed and validated for the determination of deferasirox in human plasma. To achieve the protein precipitation, the analytes were extracted from aliquots of 200 μL human plasma with acetonitrile. Chromatographic separation was performed on an ODS-C18 column with the mobile phase consisted of methanol and 0.1% formic acid containing 0.04 mM ethylenediamine tetraacetate dihydrate (EDTA) (80:20, v/v) at a flow rate of 0.5 mL/min. Deferasirox and the internal standard (IS, mifepristone) were detected using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the precursor-to-product ion transitions m/z 374.2 → 108.1 for deferasirox and m/z 430.1 → 372.2 for the IS. The method exhibited good linearity over the concentration range of 0.04-40 μg/mL for deferasirox. The method was successfully applied to a pharmacokinetic study in 10 Chinese healthy volunteers after oral administration of deferasirox. Copyright © 2018 Elsevier B.V. All rights reserved.

Validation of a Commercially Available Enzyme ImmunoAssay for the Determination of Oxytocin in Plasma Samples from Seven Domestic Animal Species.

PubMed

Bienboire-Frosini, Cecile; Chabaud, Camille; Cozzi, Alessandro; Codecasa, Elisa; Pageat, Patrick

2017-01-01

The neurohormone oxytocin (OT) has a broad range of behavioral effects in mammals. It modulates a multitude of social behaviors, e.g., affiliative and sexual interactions. Consequently, the OT role in various animal species is increasingly explored. However, several issues have been raised regarding the peripheral OT measurement. Indeed, various methods have been described, leading to assay discrepancies and inconsistent results. This highlights the need for a recognized and reliable method to measure peripheral OT. Our aim was to validate a method combining a pre-extraction step, previously demonstrated as essential by several authors, and a commercially available enzyme immunoassay (EIA) for OT measurement, using plasma from seven domestic species (cat, dog, horse, cow, pig, sheep, and goat). The Oxytocin EIA kit (EnzoLifeSciences) was used to assay the solid-phase extracted samples following the manufacturer's instructions with slight modifications. For all species except dogs and cats, concentration factors were applied to work above the kit's sensitivity (15 pg/ml). To validate the method, the following performance characteristics were evaluated using Validation Samples (VS) at various concentrations in each species: extraction efficiency via spiking tests and intra- and inter-assay precision, allowing for the calculation of total errors. Parallelism studies to assess matrix effects could not be performed because of too low basal concentrations. Quantification ranges and associated precision profiles were established to account for the various OT plasma concentrations in each species. According to guidelines for bioanalytical validation of immunoassays, the measurements were sufficiently precise and accurate in each species to achieve a total error ≤30% in each VS sample. In each species, the inter-assay precision after 3 runs was acceptable, except in low concentration samples. The linearity under dilution of dogs and cats' samples was verified. Although matrix effects assessments are lacking, our results indicate that OT plasma levels can reliably be measured in several domestic animal species by the method described here. Studies involving samples with low OT plasma concentrations should pay attention to reproducibility issues. This work opens new perspectives to reliably study peripheral OT in a substantial number of domestic animal species in various behavioral contexts.

Validation of an HPLC method for the determination of urinary and plasma levels of N1-methylnicotinamide, an endogenous marker of renal cationic transport and plasma flow.

PubMed

Musfeld, C; Biollaz, J; Bélaz, N; Kesselring, U W; Decosterd, L A

2001-01-01

N1-Methylnicotinamide (NMN) is an endogenous cationic metabolite of nicotinamide (niacine, vitamine PP) whose renal clearance reflects both the capacity of the renal tubular transport system to secrete organic cations and renal plasma flow. NMN is present in human plasma and urine at the 1-117-ng ml(-1) and 0.5-25-microg ml(-1) concentration range, respectively, and its level depends notably on pathophysiological (age, renal or hepatic diseases) conditions. We report the optimization and validation of an HPLC method for the measurement of endogenous NMN in biological fluids after derivatization into a fluorescent compound. Plasma is first deproteinized with TCA 20% and the urine diluted 1:10 with HCI 10(-4) M prior to the derivatization procedure, which includes a condensation reaction of NMN with acetophenone in NaOH at 0 degrees C, followed by dehydration in formic acid and subsequent formation of the fluorescent 1,6-naphthyridine derivatives after heating samples in a boiling water bath. The synthetic homologous derivative N1-ethylnicotinamide (NEN) reacts similarly and is added as internal standard into the biological fluid. The reaction mixture is subjected to reverse phase high performance liquid chromatography on a Nucleosil 100-C18 column using a mobile phase (acetonitrile 22%, triethylamine 0.5%, 0.01 M sodium heptanesulfonate adjusted to pH 3.2), delivered isocratically at a flow rate of 1 ml min(-1), NMN and NEN are detected at 7.8 and 10 min by spectrofluorimetry with excitation and emission wavelengths set at 366 and 418 nm, respectively. The addition-calibration method is used with plasma and urine pools. Calibration curves (using the internal standard method) are linear (r2 > 0.997) at concentrations up to 109 ng ml(-1) and 15.7 microg ml(-1) in plasma and urine, respectively. Both intra- and inter-assay precision of plasma control samples at 10, 50 and 90 ng ml(-1) were lower than 3.3% and concentrations not deviating more than 2.7% from their nominal values. In urine intra- and inter-assay CVs of control samples at 1, 5 and 9 microg ml(-1) are lower than 8.3%, with concentrations not deviating more than -9.0 to +11.8% from their nominal values. This analytical method has therefore the required sensitivity and selectivity to measure NMN in plasma and urine, enabling the non-invasive determination of the tubular secretory capacity of the kidney and the renal plasma flow.

Development of water-phase derivatization followed by solid-phase microextraction and gas chromatography/mass spectrometry for fast determination of valproic acid in human plasma.

PubMed

Deng, Chunhui; Li, Ning; Ji, Jie; Yang, Bei; Duan, Gengli; Zhang, Xiangmin

2006-01-01

In this study, a simple, rapid, and sensitive method was developed and validated for the quantification of valproic acid (VPA), an antiepileptic drug, in human plasma, which was based on water-phase derivatization followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC/MS). In the proposed method, VPA in plasma was rapidly derivatized with a mixture of isobutyl chloroformate, ethanol and pyridine under mild conditions (room temperature, aqueous medium), and the VPA ethyl ester formed was headspace-extracted and simultaneously concentrated using the SPME technique. Finally, the analyte extracted on SPME fiber was analyzed by GC/MS. The experimental parameters and method validations were studied. The optimal conditions were obtained: PDMS fiber, stirring rate of 1100 rpm, sample temperature of 80 degrees C, extraction time of 20 min, NaCl concentration of 30%. The proposed method had a limit of quantification (0.3 microg/mL), good recovery (89-97%) and precision (RSD value less than 10%). Because the proposed method combined a rapid water-phase derivatization with a fast, simple and solvent-free sample extraction and concentration technique of SPME, the sample preparation time was less than 25 min. This much shortens the whole analysis time of VPA in plasma. The validated method has been successfully used to analyze VPA in human plasma samples for application in pharmacokinetic studies. All these results show that water-phase derivatization followed by HS-SPME and GC/MS is an alternative and powerful method for fast determination of VPA in biological fluids. Copyright 2006 John Wiley & Sons, Ltd.

L-Phenylalanine concentration in blood of phenylketonuria patients: a modified enzyme colorimetric assay compared with amino acid analysis, tandem mass spectrometry, and HPLC methods.

PubMed

De Silva, Veronica; Oldham, Charlie D; May, Sheldon W

2010-09-01

Phenylketonuria (PKU) is an autosomal recessive disorder caused by an impaired conversion of L-phenylalanine (Phe) to L-tyrosine, typically resulting from a deficiency in activity of a hepatic and renal enzyme L-phenylalanine hydroxylase. The disease is characterized by an increased concentration of Phe and its metabolites in body fluids. A modified assay based on an enzymatic-colorimetric methodology was developed for measuring blood Phe levels in PKU patients; this method is designed for use with undeproteinized samples and avoids the use of solvents or amphiphilic agents. Thus, the method could be suitable for incorporation into a simple home-monitoring device. We report here on a comparison of blood Phe concentrations in PKU patients measured in undeproteinized plasma using this enzyme colorimetric assay (ECA), with values determined by amino acid analysis (AAA) of deproteinized samples, and HPLC and tandem mass spectrometry (MS/MS) analyses of dried blood spot (DBS) eluates. Pearson correlation coefficients of 0.951, 0.976 and 0.988 were obtained when AAA-measured Phe concentrations were compared with the ECA-, HPLC- or MS/MS-measured values, respectively. A Bland-Altman analysis revealed that mean Phe concentrations determined using AAA were on average 65 μmol/L lower than values measured by our ECA. These results may be the result of minimizing the manipulations performed on the patient sample compared with AAA, HPLC, and MS/MS methods, which involve plasma deproteinization or DBS elution and derivatization. The results reported here confirm that Phe concentrations determined by our ECA method are comparable to those determined by other widely used methods for a broad range of plasma Phe concentrations.

Development and Validation of a Sensitive LC-MS/MS Method for the Determination of Fenoterol in Human Plasma and Urine Samples

PubMed Central

Sanghvi, M.; Ramamoorthy, A.; Strait, J.; Wainer, I. W.; Moaddel, R.

2013-01-01

Due to the lack of sensitivity in current methods for the determination of fenoterol (Fen). A rapid, LC-MS/MS method was developed for the determination of (R,R′)-Fen and (R,R′;S,S′)-Fen in plasma and urine. The method was fully validated and was linear from 50 pg/ml to 2000 pg/ml for plasma and from 2.500 ng/ml to 160 ng/ml for urine with a lower limit of quantitation of 52.8 pg/ml in plasma. The coefficient of variation was <15% for the high QC standards and <10% for the low QC standards in plasma and was <15% for the high and low QC standards in urine. The relative concentrations of (R,R′)-Fen and (S,S′)-Fen were determined using a chirobiotic T chiral stationary phase. The method was used to determine the concentration of (R,R′)-Fen in plasma and urine samples obtained in an oral cross-over study of (R,R′)-Fen and (R,R′;S,S′)-Fen formulations. The results demonstrated a potential pre-systemic enantioselective interaction in which the (S,S′)-Fen reduces the sulfation of the active (R,R′)-Fen. The data suggests that a non-racemic mixture of the Fen enantiomers may provide better bioavailability of the active (R,R′)-Fen for use in the treatment of cardiovascular disease PMID:23872161

Quantitative determination of metformin, glyburide and its metabolites in plasma and urine of pregnant patients by LC-MS/MS.

PubMed

Zhang, Xing; Wang, Xiaoming; Vernikovskaya, Daria I; Fokina, Valentina M; Nanovskaya, Tatiana N; Hankins, Gary D V; Ahmed, Mahmoud S

2015-04-01

This report describes the development and validation of an LC-MS/MS method for the quantitative determination of glyburide (GLB), its five metabolites (M1, M2a, M2b, M3 and M4) and metformin (MET) in plasma and urine of pregnant patients under treatment with a combination of the two medications. The extraction recovery of the analytes from plasma samples was 87-99%, and that from urine samples was 85-95%. The differences in retention times among the analytes and the wide range of the concentrations of the medications and their metabolites in plasma and urine patient samples required the development of three LC methods. The lower limit of quantitation (LLOQ) of the analytes in plasma samples was as follows: GLB, 1.02 ng/mL; its five metabolites, 0.100-0.113 ng/mL; and MET, 4.95 ng/mL. The LLOQ in urine samples was 0.0594 ng/mL for GLB, 0.984-1.02 ng/mL for its five metabolites and 30.0 µg/mL for MET. The relative deviation of this method was <14% for intra-day and inter-day assays in plasma and urine samples, and the accuracy was 86-114% in plasma, and 94-105% in urine. The method described in this report was successfully utilized for determining the concentrations of the two medications in patient plasma and urine. Copyright © 2014 John Wiley & Sons, Ltd.

Quantitative determination of metformin, glyburide and its metabolites in plasma and urine of pregnant patients by LC-MS/MS

PubMed Central

Zhang, Xing; Wang, Xiaoming; Vernikovskaya, Daria I.; Fokina, Valentina M.; Nanovskaya, Tatiana N.; Hankins, Gary D.V.; Ahmed, Mahmoud S.

2014-01-01

This report describes the development and validation of an LC-MS/MS method for the quantitative determination of glyburide (GLB), its five metabolites (M1, M2a, M2b, M3, and M4) and metformin (MET) in plasma and urine of pregnant patients under treatment with a combination of the two medications. The extraction recovery of the analytes from plasma samples ranged between 87% and 99%, and 85%–95% for urine samples. The differences in retention times among the analytes, and the wide range of the concentrations of the medications and their metabolites in plasma and urine patient samples required the development of three LC methods. The lower limit of quantitation (LLOQ) of the analytes in plasma samples was as follows: GLB, 1.02 ng/mL; its five metabolites, 0.100–0.113 ng/mL and 4.95 ng/mL for MET. LLOQ in urine samples was 0.0594 ng/mL for GLB, 0.984–1.02 ng/mL for its five metabolites and 30.0 μg/mL for MET. The relative deviation of this method was < 14% for intra-day and inter-day assays in plasma and urine samples, and the accuracy ranged between 86% and 114% in plasma, and 94% to 105% in urine. The method described in this report was successfully utilized for determining the concentrations of the two medications in patient plasma and urine. PMID:25164921

The Influence of Dietary Habits and Meat Consumption on Plasma 3‐Methylhistidine—A Potential Marker for Muscle Protein Turnover

PubMed Central

Kochlik, Bastian; Gerbracht, Christiana; Grune, Tilman

2018-01-01

Scope 3‐Methylhistidine (3‐MH) as a potential biomarker for muscle protein turnover is influenced by meat intake but data on the impact of meat on plasma 3‐MH are scarce. We determined the association of plasma 3‐MH, 1‐methylhistidine (1‐MH), and creatinine with dietary habits and assessed the impact of a single white meat intervention during a meat‐free period. Methods and results Plasma 3‐MH, 1‐MH, and creatinine concentrations of healthy young omnivores (n = 19) and vegetarians (n = 16) were analyzed together with data on anthropometry, body composition, grip strength, and nutrition. After baseline measurements omnivores adhered to a meat‐free diet for 6 days and received a defined administration of chicken breast on day four. At baseline, omnivores had higher plasma 3‐MH and 1‐MH concentrations than vegetarians. White meat administration led to a slight increase in plasma 3‐MH in omnivores. The elevated 3‐MH concentrations significantly declined within 24 h after white meat intake. Conclusion 1‐MH concentrations in plasma seem to be suitable to display (white) meat consumption and its influence on 3‐MH plasma concentration. 3‐MH in plasma may be used as a biomarker for muscle protein turnover if subjects have not consumed meat in the previous 24 h. PMID:29573154

Study of a Two-Step Centrifugation Protocol for Concentrating Cells and Growth Factors in Bovine Platelet-Rich Plasma

PubMed Central

Gutiérrez, Claudia M.; López, Catalina

2017-01-01

There is a lack of information about the methods used for bovine platelet-rich plasma (PRP)/platelet-rich gel (PRG) procurement, including information on platelet (PLT), white blood cell (WBC) in PRP, and growth factor release from PRG supernatants. The aims of this study were to compare and to correlate the PLT, WBC, transforming growth factor beta-1 (TGF-β1), and platelet-derived growth factor BB (PDGF-BB) concentrations in bovine whole blood, plasma, and four PRP layers and their respective PRG supernatants: A and B (obtained by a single centrifugation tube method at 720g/5 min) and C and D (obtained by a double centrifugation tube method, by using two centrifugation episodes at 720g/5 min). PLT and WBC counts were significantly higher in PRP-C, followed by whole blood, PRP-A, PRP-B, and PRP-D. TGF-β1 concentrations were significantly higher in PRG-B supernatants and its correspondent PRP-B lysate when compared to the other PRG supernatants and plasma. Supernatants from PRG-A, PRG-B, and PRG-D had equivalent TGF-β1 concentrations. PDGF-BB concentrations were not statistically different between the hemoderivatives. Significant Pearson correlations were noted between PLT counts and WBC counts (0.8) and between PLT counts and PLT distribution width (0.6). Further studies should be performed to assess the potential clinical applications of these PRPs. PMID:29214094

Comparison of several von Willebrand factor (VWF) activity assays for monitoring patients undergoing treatment with VWF/FVIII concentrates: improved performance with a new modified automated method.

PubMed

Hillarp, A; Friedman, K D; Adcock-Funk, D; Tiefenbacher, S; Nichols, W L; Chen, D; Stadler, M; Schwartz, B A

2015-11-01

The ability of von Willebrand factor (VWF) to bind platelet GP Ib and promote platelet plug formation is measured in vitro using the ristocetin cofactor (VWF:RCo) assay. Automated assay systems make testing more accessible for diagnosis, but do not necessarily improve sensitivity and accuracy. We assessed the performance of a modified automated VWF:RCo assay protocol for the Behring Coagulation System (BCS(®) ) compared to other available assay methods. Results from different VWF:RCo assays in a number of specialized commercial and research testing laboratories were compared using plasma samples with varying VWF:RCo activities (0-1.2 IU mL(-1) ). Samples were prepared by mixing VWF concentrate or plasma standard into VWF-depleted plasma. Commercially available lyophilized standard human plasma was also studied. Emphasis was put on the low measuring range. VWF:RCo accuracy was calculated based on the expected values, whereas precision was obtained from repeated measurements. In the physiological concentration range, most of the automated tests resulted in acceptable accuracy, with varying reproducibility dependent on the method. However, several assays were inaccurate in the low measuring range. Only the modified BCS protocol showed acceptable accuracy over the entire measuring range with improved reproducibility. A modified BCS(®) VWF:RCo method can improve sensitivity and thus enhances the measuring range. Furthermore, the modified BCS(®) assay displayed good precision. This study indicates that the specific modifications - namely the combination of increased ristocetin concentration, reduced platelet content, VWF-depleted plasma as on-board diluent and a two-curve calculation mode - reduces the issues seen with current VWF:RCo activity assays. © 2015 John Wiley & Sons Ltd.

Comparison of the docetaxel concentration in human plasma measured with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a nanoparticle immunoassay and clinical applications of that assay.

PubMed

Geng, Chunmei; Li, Pingli; Chen, Xuwang; Yuan, Guiyan; Guo, Nan; Liu, Huanjun; Zhang, Rui; Guo, Ruichen

2017-05-23

To determine the feasibility of using a nanoparticle immunoassay for clinical therapeutic drug monitoring (TDM) of docetaxel concentrations, a sensitive and simple method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established to measure the docetaxel concentration in human plasma and the results of LC-MS/MS and the immunoassay were compared. Docetaxel and paclitaxel (the internal standard, or IS) in human plasma were extracted through protein precipitation, separated on a Diamonsil C18 column (150 mm × 4.6 mm, 5 μm), ionized with positive ions, and detected with LC-MS/MS in multi-reaction monitoring (MRM) mode. Plasma samples from 248 cancer patients were assayed with LC-MS/MS and a nanoparticle immunoassay. Data from the samples were analyzed with the statistical software SPSS and the software MedCalc. Results indicated that the calibration curve of the validated method of LC-MS/MS was linear over the range of 10-2,000 ng/mL, with an lowest limit of quantitation (LLOQ) of 10 ng/mL, and the intra- and inter- day precision and accuracy were both < ± 15%. Comparison of the two methods indicated that results of the LC-MS/MS were closely related to those of the nanoparticle immunoassay, with a correlation coefficient (R) of 0.965 and acceptable 95% confidence intervals (CI) of ‒ 231.7-331.1 ng/mL. Overall, the established method of LC-MC/MS and the nanoparticle immunoassay were both suitable for measurement of the docetaxel concentration in human plasma, and the immunoassay was far more cost-effective and better at clinical TDM of docetaxel in clinical practice.

Development of SPME-LC-MS method for screening of eight beta-blockers and bronchodilators in plasma and urine samples.

PubMed

Goryński, Krzysztof; Kiedrowicz, Alicja; Bojko, Barbara

2016-08-05

The current work describes the development and validation of a simple, efficient, and fast method using solid phase microextraction coupled to liquid chromatography-tandem mass spectrometry (SPME-LC-MS/MS) for the concomitant measurement of eight beta-blockers and bronchodilators in plasma and urine. The presented assay enables quantitative determination of acebutolol, atenolol, fenoterol, nadolol, pindolol, procaterol, sotalol, and timolol. In this work, samples were prepared on a high-throughput platform using the 96-well plate format of the thin film solid phase microextraction (TFME) system, and a biocompatible extraction phase made of hydrophilic-lipophilic balance particles. Analytes were separated on a pentafluorophenyl column (100mm×2.1mm, 3μm) by gradient elution using an UPLC Nexera coupled with an LCMS-8060 mass spectrometer. The mobile phase consisted of water-acetonitrile (0.1% formic acid) at a flow rate of 0.4mLmin(-1). The linearity of the method was checked within therapeutic blood-plasma concentrations, and shown to adequately reflect typically expected concentrations of future study samples. Post-extraction addition experiments showed that the matrix effect ranged in plasma from 98% for procaterol to 115% for nadolol, and in urine, from 85% for nadolol and pindolol to 119% for atenolol. The method was successfully validated using Food and Drug Administration (FDA) guidelines, and met all acceptance criteria for bioanalytical assays at five concentration levels for all selected drugs. The final protocol can be successfully applied for monitoring concentrations of the selected drugs in both plasma and urine matrices obtained from patients or athletes. Copyright © 2016 Elsevier B.V. All rights reserved.

Concentric micro-nebulizer for direct sample insertion

DOEpatents

Fassel, V.A.; Rice, G.W.; Lawrence, K.E.

1984-03-06

A concentric micro-nebulizer and method for introducing liquid samples into a plasma established in a plasma torch including a first tube connected to a source of plasma gas. The concentric micro-nebulizer has inner and outer concentric tubes extending upwardly within the torch for connection to a source of nebulizer gas and to a source of liquid solvent and to a source of sample liquid. The inner tube is connected to the source of liquid solvent and to the source of sample liquid and the outer tube is connected to the source of nebulizer gas. The outer tube has an orifice positioned slightly below the plasma when it is established, with the inner and outer tubes forming an annulus therebetween with the annular spacing between the tubes at said orifice being less than about 0.05mm. The dead volume of the inner tube is less than about 5 microliters.

Concentric micro-nebulizer for direct sample insertion

DOEpatents

Fassel, Velmer A.; Rice, Gary W.; Lawrence, Kimberly E.

1986-03-11

A concentric micro-nebulizer and method for introducing liquid samples into a plasma established in a plasma torch including a first tube connected to a source of plasma gas. The concentric micro-nebulizer has inner and outer concentric tubes extending upwardly within the torch for connection to a source of nebulizer gas and to a source of liquid solvent and to a source of sample liquid. The inner tube is connected to the source of liquid solvent and to the source of sample liquid and the outer tube is connected to the source of nebulizer gas. The outer tube has an orifice positioned slightly below the plasma when it is established, with the inner and outer tubes forming an annulus therebetween with the annular spacing between the tubes at said orifice being less than about 0.05 mm. The dead volume of the inner tube is less than about 5 microliters.

Maternal and cord plasma concentrations of beta-lipotrophin, beta-endorphin and gamma-lipotrophin at delivery; effect of analgesia.

PubMed

Browning, A J; Butt, W R; Lynch, S S; Shakespear, R A; Crawford, J S

1983-12-01

Maternal venous plasma concentrations of beta-LPH, beta-EP and gamma-LPH were compared in (i) patients undergoing vaginal delivery, 11 with an epidural block and 13 with pethidine and nitrous oxide or no analgesics; (ii) patients delivered by caesarean section, 7 under epidural block and 8 under general anaesthesia. Patients delivered by either method under epidural block had significantly lower levels of all three peptides than those receiving no epidural. There were significant negative correlations between umbilical vein beta-LPH, beta-EP and gamma-LPH concentrations and umbilical artery pH and positive correlations between beta-LPH and beta-EP but not gamma-LPH and cord PCO2 in 29 patients. There was no relation between cord levels of any of the three peptides and the method of analgesia or the route of delivery. Although concentrations of all three peptides were closely correlated to one another in either maternal or cord plasma, there was no relationship between maternal and fetal levels.

Development and Clinical Application of a New Method for the Radioimmunoassay of Arginine Vasopressin in Human Plasma

PubMed Central

Robertson, Gary L.; Mahr, Ermelinda A.; Athar, Shahid; Sinha, Tushar

1973-01-01

A radioimmunoassay has been developed that permits reliable measurements of plasma arginine vasopressin (AVP) at concentrations as low as 0.5 pg/ml in sample volumes of 1 ml or less. Nonhormonal immunoreactivity associated with the plasma proteins is eliminated by acetone precipitation before assay, leaving unaltered a component that is immunologically and chromatographically indistinguishable from standard AVP. Storage of plasma results in a decline in AVP concentration and, thus, must be carefully regulated. The plasma AVP values obtained by our method approximate the anticipated levels and vary in accordance with physiologic expections. In recumbent normal subjects, plasma AVP ranged from (mean ±SD) 5.4±3.4 pg/ml after fluid deprivation to 1.4±0.8 pg/ml after water loading, and correlated significantly with both plasma osmolality (r=0.52; P<0.001) and urine osmolality (r=0.77; P<0.001). After fluid restriction, plasma AVP was uniformly normal relative to plasma osmolality in patients with nephrogenic diabetes insipidus and primary polydipsia but was distinctly subnormal in all patients with pituitary diabetes insipidus. The infusion of physiologic amounts of posterior pituitary extract caused a dose-related rise in plasma vasopressin that afterwards declined at the expected rate (t½=22.5±4 min). We conclude that, when used appropriately, our radioimmunoassay method provides a useful way of assessing AVP function in man. PMID:4727463

A simple high-performance liquid chromatographic method for the determination of acyclovir in human plasma and application to a pharmacokinetic study.

PubMed

Yu, Liyan; Xiang, Bingren; Zhan, Ying

2008-01-01

A rapid, simple and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the measurement of acyclovir (CAS 59277-89-3) concentrations in human plasma and its use in bioavailability studies is evaluated. The method was linear in the concentration range of 0.05-4.0 microg/ml. The lower limit of quantification (LLOQ) was 0.05 microg/ml in 0.5 ml plasma sample. The intra- and inter-day relative standard deviations across three validation runs over the entire concentration range were less than 8.2%. This method was successfully applied for the evaluation of pharmacokinetic profiles of acyclovir capsule in 19 healthy volunteers. The main pharmacokinetic parameters obtained were: AUC(o-t) 6.50 +/- 1.47 and 7.13 +/- 1.44 microg x h/ml, AUC(0-infinity) 6.77 +/- 1.48 and 7.41 +/- 1.49 microg x h/ml, C(max) 2.27 +/- 0.57 and 2.27 +/- 0.62 microg/ml, t(1/2) 2.96 +/- 0.41 and 2.88 +/- 0.33 h, t(max) 0.8 +/- 0.3 and 1.0 +/- 0.5 h for test and reference formulations, respectively. No statistical differences were observed for C(max) and the area under the plasma concentration--time curve for acyclovir. 90% confidence limits calculated for C(max) and AUC from zero to infinity (AUC(0-infinity)) of acyclovir were included in the bioequivalence range (0.8-1.25 for AUC).

Assessing matrix, interferences and comparability between the Abbott Diagnostics and the Beckman Coulter high-sensitivity cardiac troponin I assays.

PubMed

Kavsak, Peter A; Malinowski, Paul; Roy, Chantele; Clark, Lorna; Lamers, Shana

2018-03-13

Analytical evaluation of high-sensitivity cardiac troponin (hs-cTn) assays, with particular attention to imprecision, interferences and matrix effects, at normal cTn concentrations, is of utmost importance as many different clinical algorithms use concentration cutoffs <10 ng/L for decision-making. The objective for the present analytical study was to compare the new Beckman Coulter hs-cTnI assay (Access hsTnI) to Abbott's hs-cTnI assay in different matrices and for different interferences, with a focus on concentrations <10 ng/L. The limit of blank (LoB) and the limit of detection (LoD) were determined in different matrices for the Beckman hs-cTnI assay. Passing-Bablok regression and difference plots were determined for 200 matched lithium heparin and EDTA plasma samples for the Beckman assay and 200 lithium heparin samples for the Abbott assay. Both EDTA and heparin plasma samples were also evaluated for stability under refrigerated conditions, for endogenous alkaline phosphatase interference and for hemolysis and icterus. The Beckman hs-cTnI assay LoB was 0.5 ng/L with the following range of LoDs=0.8-1.2 ng/L, with EDTA plasma yielding lower concentrations as compared to lithium heparin plasma (mean difference=-14.9%; 95% CI=-16.9 to 12.9). Below 10 ng/L, lithium heparin cTnI results from the Beckman assay were on average 1.1 ng/L (95% CI=0.7 to 1.5) higher than the Abbott results, with no difference between the methods when using EDTA plasma (mean difference =-0.1 ng/L; 95% CI=-0.3 to 0.2). Low cTnI concentrations were less effected by interferences in EDTA plasma. The Access hsTnI method can reliably detect normal cTnI concentrations with both lithium heparin and EDTA plasma being suitable matrices.

Validated method to measure yakuchinone A in plasma by LC-MS/MS and its application to a pharmacokinetic study in rats

PubMed Central

2014-01-01

Background Yakuchinone A has a plethora of beneficial biological effects. However, the pharmacokinetic (PK) data of yakuchinone A still remain unknown so far. Furthermore, the quantification of yakuchinone A in biological samples has not been reported in the literature. Therefore, in the present study we aimed to develop a new method for the fast, efficient and accurate assessment of yakuchinone A concentration in plasma, as a means for facilitating the PK evaluation of yakuchinone A. Results A liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the determination of yakuchinone A in rat plasma. Mass spectrometric and chromatographic conditions were optimized. Plasma samples were pretreated by protein precipitation with methanol. LC separation was performed on a Phenomenex Luna C18 column with gradient elution using a mobile phase consisting of methanol–water containing 0.5 mM formic acid (HCOOH) at a flow rate of 0.28 mL/min. ESI-MS spectra were acquired in positive ion multiple reaction monitoring mode (MRM). The precursor-to-product ion pairs used for MRM of yakuchinone A and yakuchinone B were m/z 313.1 → 137.0 and 311.2 → 117.1, respectively. Low concentration of HCOOH reduced the ion suppression caused by matrix components and clearly improved the analytical sensitivity. Yakuchinone A showed good linearity over a wide concentration range (r > 0.99). The accuracy, precision, stability and linearity were found to be within the acceptable criteria. This new method was successfully applied to analyze the rat plasma concentration of parent yakuchinone A after a single oral administration of SuoQuan capsules. Low systemic exposure to parent yakuchinone A was observed. Conclusion The proposed method is sensitive and reliable. It is hoped that this new method will prove useful for the future PK studies. PMID:24422995

Changes in plasma GABA concentration during vigabatrin treatment of epilepsy: a prospective study.

PubMed

Erdal, J; Gram, L; Alving, J; Löscher, W

1999-04-01

The aim of the present prospective study was to evaluate changes in plasma GABA concentration in relation to clinical response during vigabatrin treatment of epilepsy. We studied 29 patients with uncontrolled partial-onset seizures during open add-on vigabatrin treatment and measured plasma GABA and vigabatrin concentrations by a sensitive HPLC method. Following short-term treatment 17 out of 28 patients had a seizure reduction of > 50% (responders). After long-term treatment 16 out of 22 patients were responders. There was no difference between responders and nonresponders regarding pretreatment seizure frequency, treatment duration, vigabatrin dose, or plasma vigabatrin concentration. Responders had a significant (p < 0.001) increase in mean plasma GABA both after short-term (from 0.380 to 0.530 nmol/ml; mean increase: 48%) and after long-term (from 0.392 to 0.618 nmol/ml; mean increase: 71%) vigabatrin treatment, whilst nonresponders had no significant changes in GABA levels. However, since plasma GABA increased in a subgroup of nonresponders, mean plasma GABA levels did not differ between responders and nonresponders. Although plasma GABA increased significantly in the responder but not in the nonresponder group during vigabatrin treatment of patients with epilepsy, it does not seem to be a reliable marker of individual clinical response to vigabatrin treatment.

Plasmatic antioxidant capacity due to ascorbate using TEMPO scavenging and electron spin resonance.

PubMed

Piehl, Lidia L; Facorro, Graciela B; Huarte, Mónica G; Desimone, Martín F; Copello, Guillermo J; Díaz, Luis E; de Celis, Emilio Rubín

2005-09-01

Ascorbate is the most effective water-soluble antioxidant and its plasma concentration is usually measured by different methods including colorimetric assays, HPLC or capillary electrophoresis. Plasma antioxidant capacity is determined by indexes such as total reactive antioxidant potential, total antioxidant reactivity, oxygen radical absorbance capacity, etc. We developed an alternative method for the evaluation of the plasma antioxidant status due to ascorbate. TEMPO kinetics scavenging analyzed by ESR spectroscopy was performed on plasma samples in different antioxidant situations. Plasma ascorbate concentrations were determined by capillary electrophoresis. Ascorbyl radical levels were measured by ESR. Plasma reactivity with TEMPO (PR-T) reflected plasma ascorbate levels. Average PR-T for normal plasmas resulted 85+/-27 micromol/l (n=43). PR-T during ascorbic acid intake (1 g/day) increased to an average value of 130+/-20 micromol/l (p<0.001, n=20). PR-T correlated with the plasmatic ascorbate levels determined by capillary electrophoresis (r=0.92), presenting as an advantage the avoiding of the deproteination step. Plasma ascorbyl radical levels increase from 16+/-2 to 24+/-3 nmol/l (p<0.005, n=14) after ascorbate intake. PR-T could be considered as a measure of the plasmatic antioxidant capacity due to the plasma ascorbate levels and could be useful to investigate different antioxidant situations.

On the quantification of the dissolved hydroxyl radicals in the plasma-liquid system using the molecular probe method

NASA Astrophysics Data System (ADS)

Ma, Yupengxue; Gong, Xinning; He, Bangbang; Li, Xiaofei; Cao, Dianyu; Li, Junshuai; Xiong, Qing; Chen, Qiang; Chen, Bing Hui; Huo Liu, Qing

2018-04-01

Hydroxyl (OH) radical is one of the most important reactive species produced by plasma-liquid interactions, and the OH in liquid phase (dissolved OH radical, OHdis) takes effect in many plasma-based applications due to its high reactivity. Therefore, the quantification of the OHdis in a plasma-liquid system is of great importance, and a molecular probe method usually used for the OHdis detection might be applied. Herein, we investigate the validity of using the molecular probe method to estimate the [OHdis] in the plasma-liquid system. Dimethyl sulfoxide is used as the molecular probe to estimate the [OHdis] in an air plasma-liquid system, and usually the estimation of [OHdis] is deduced by quantifying the OHdis-induced derivative, the formaldehyde (HCHO). The analysis indicates that the true concentration of the OHdis should be estimated from the sum of three terms: the formed HCHO, the existing OH scavengers, and the H2O2 formed from the OHdis. The results show that the measured [HCHO] needs to be corrected since the HCHO consumption is not negligible in the plasma-liquid system. We conclude from the results and the analysis that the molecular probe method generally underestimates the [OHdis] in the plasma-liquid system. If one wants to obtain the true concentration of the OHdis in the plasma-liquid system, one needs to know the consumption behavior of the OHdis-induced derivatives, the information of the OH scavengers (such as hydrated electron, atomic hydrogen besides the molecular probe), and also the knowledge of the H2O2 formed from the OHdis.

Extractive alkylation of 6-mercaptopurine and determination in plasma by gas chromatography-mass spectrometry.

PubMed

Floberg, S; Hartvig, P; Lindström, B; Lönner-Holm, G; Odlind, B

1981-09-11

An analytical procedure was developed for the determination of 6-mercaptopurine in plasma. Owing to the polar character and low plasma concentration of the compound, extraction and derivatization was carried out directly from the plasma sample by extractive alkylation. Determination was made using gas chromatography-mass spectrometry with multiple-ion detection. Conditions with respect to the rate of formation and the stability of the derivative formed in the extractive alkylation step were evaluated. The selectively of the method to azathioprine and to metabolites was thoroughly investigated. No 6-mercaptopurine was formed from azathioprine added to water or plasma and run through the method. The method enables the detection of 2 ng of 6 mercaptopurine in a 1.0-ml plasma sample. Quantitative determinations were done down to 10 ng/ml 6 mercaptopurine in plasma.

Spectroscopy peculiarities of thermal plasma of electric arc discharge between electrodes with Zn admixtures

NASA Astrophysics Data System (ADS)

Semenyshyn, R. V.; Veklich, A. N.; Babich, I. L.; Boretskij, V. F.

2014-10-01

Plasma of the free burning electric arc between Ag-SnO2-ZnO composite electrodes as well as brass electrodes were investigated. The plasma temperature distributions were obtained by Boltzmann plot method involving Cu I, Ag I or Zn I spectral line emissions. The electron density distributions were obtained from the width and from absolute intensity of spectral lines. The laser absorption spectroscopy was used for measurement of copper atom concentration in plasma. Plasma equilibrium composition was calculated using two independent groups of experimental values (temperature and copper atom concentration, temperature and electron density). It was found that plasma of the free burning electric arc between brass electrodes is in local thermodynamical equilibrium. The experimental verification of the spectroscopic data of Zn I spectral lines was carried out.

The potential influence of CO2, as an agent for euthanasia, on the pharmacokinetics of basic compounds in rodents.

PubMed

Angus, Derek W; Baker, James A; Mason, Rona; Martin, Iain J

2008-02-01

Rodent tissue distribution and pharmacokinetic studies were performed on basic compounds Org A and Org B in support of central nervous system drug discovery programs. A consistent observation from these studies was that drug concentrations in plasma obtained by cardiac puncture after CO(2) euthanasia were markedly higher compared with those from other sampling methods (serial sampling, isoflurane anesthesia, or cervical dislocation). Further investigations demonstrated that CO(2) euthanasia led to a reduction in blood pH in both rats and mice, which was not observed with the other sampling methods. The use of CO(2) euthanasia resulted in a decrease in the brain/plasma ratio of Org B, largely as a result of increased plasma concentrations. The pharmacokinetics of a basic drug, raloxifene, in rat were also influenced by sampling technique. CO(2) euthanasia before sampling, resulted in a 2- to 3-fold increase in the area under the drug concentration-time curve, a decrease in plasma clearance, and a decrease in the steady-state volume of distribution compared with isoflurane anesthesia. It is proposed that a decrease in the pH of blood relative to that of other tissues, as a consequence of CO(2) exposure, results in a redistribution of basic compounds out of the tissues, leading to higher concentrations in plasma.

Pharmacokinetic Interaction Study of Ranitidine and Daijokito in Healthy Volunteers

PubMed Central

Endo, Yusuke; Ishihara, Yoshitaka; Tsuno, Satoshi; Matsuda, Akiko; Qian, Weibin; Miura, Norimasa; Hasegawa, Junichi

2016-01-01

Background Ranitidine is a histamine 2 receptor antagonist, and daijokito is a Kampo (Chinese herbal medicine as practiced in Japan) formula, which is traditionally used for treating constipation and digestive trouble. Previous study demonstrated that daijokito significantly affected the pharmacokinetics of ranitidine in rats; however, the doses of ranitidine and daijokito in that study were higher than in clinical practice. Therefore, we examined the pharmacokinetic interaction between ranitidine and daijokito in clinical practice doses in healthy volunteers. Methods This was a randomized, open label, two-period crossover study in healthy volunteers (n = 7). Volunteers received administrations of either a single dose of ranitidine 300 mg, or ranitidine 300 mg in combination with daijokito extract granules 2.5 g. Plasma concentrations of ranitidine were measured over 12 h by LC/MS/MS method. Results Plasma concentrations of ranitidine were lower with co-administration of daijokito compared with ranitidine alone. Co-administration of daijokito significantly decreased ranitidine area under the plasma concentration-time curve from 0 to 12 h (AUC0–12) and maximum plasma concentration (Cmax) with geometric mean (GM) ratio [90% confidence interval (CI)] for AUC0–12 of 0.609 (0.449, 0.826) and Cmax of 0.515 (0.345, 0.771). Conclusion Co-administration of ranitidine with daijokito resulted in a significant decrease in plasma level of ranitidine in healthy volunteers. PMID:27493481

The measurement of insulin-like growth factor 1 in sheep plasma.

PubMed

Bruce, L A; Atkinson, T; Hutchinson, J S; Shakespear, R A; MacRae, J C

1991-02-01

A method is described for the radioimmunoassay (RIA) of insulin-like growth factor 1 (IGF-1) in neutralised formic acid-ethanol extracts of sheep plasma. The ability of the acid-ethanol pretreatment to remove the IGF-1 binding proteins (BPs), which interfere in the assay has been examined. Comparative plasma IGF-1 concentrations determined by the method correlated closely (P less than 0.001) with corresponding values where BPs were removed by acid gel filtration. The method has been applied to studies in which sheep were given exogenous growth hormone and indicated that plasma IGF-1 levels respond rapidly to the onset and termination of treatment.

Optimisation of a double-centrifugation method for preparation of canine platelet-rich plasma.

PubMed

Shin, Hyeok-Soo; Woo, Heung-Myong; Kang, Byung-Jae

2017-06-26

Platelet-rich plasma (PRP) has been expected for regenerative medicine because of its growth factors. However, there is considerable variability in the recovery and yield of platelets and the concentration of growth factors in PRP preparations. The aim of this study was to identify optimal relative centrifugal force and spin time for the preparation of PRP from canine blood using a double-centrifugation tube method. Whole blood samples were collected in citrate blood collection tubes from 12 healthy beagles. For the first centrifugation step, 10 different run conditions were compared to determine which condition produced optimal recovery of platelets. Once the optimal condition was identified, platelet-containing plasma prepared using that condition was subjected to a second centrifugation to pellet platelets. For the second centrifugation, 12 different run conditions were compared to identify the centrifugal force and spin time to produce maximal pellet recovery and concentration increase. Growth factor levels were estimated by using ELISA to measure platelet-derived growth factor-BB (PDGF-BB) concentrations in optimised CaCl 2 -activated platelet fractions. The highest platelet recovery rate and yield were obtained by first centrifuging whole blood at 1000 g for 5 min and then centrifuging the recovered platelet-enriched plasma at 1500 g for 15 min. This protocol recovered 80% of platelets from whole blood and increased platelet concentration six-fold and produced the highest concentration of PDGF-BB in activated fractions. We have described an optimised double-centrifugation tube method for the preparation of PRP from canine blood. This optimised method does not require particularly expensive equipment or high technical ability and can readily be carried out in a veterinary clinical setting.

Uridine Metabolism in HIV-1-Infected Patients: Effect of Infection, of Antiretroviral Therapy and of HIV-1/ART-Associated Lipodystrophy Syndrome

PubMed Central

Domingo, Pere; Torres-Torronteras, Javier; Pomar, Virginia; Giralt, Marta; Domingo, Joan Carles; Gutierrez, Maria del Mar; Gallego-Escuredo, José M.; Mateo, Maria Gracia; Cano-Soldado, Pedro; Fernandez, Irene; Pastor-Anglada, Marçal; Vidal, Francesc; Villarroya, Francesc; Andreu, Antoni; Marti, Ramon

2010-01-01

Background Uridine has been advocated for the treatment of HIV-1/HAART-associated lipodystrophy (HALS), although its metabolism in HIV-1-infected patients is poorly understood. Methods Plasma uridine concentrations were measured in 35 controls and 221 HIV-1-infected patients and fat uridine in 15 controls and 19 patients. The diagnosis of HALS was performed following the criteria of the Lipodystrophy Severity Grading Scale. Uridine was measured by a binary gradient-elution HPLC method. Analysis of genes encoding uridine metabolizing enzymes in fat was performed with TaqMan RT-PCR. Results Median plasma uridine concentrations for HIV-1-infected patients were 3.80 µmol/l (interquartile range: 1.60), and for controls 4.60 µmol/l (IQR: 1.8) (P = 0.0009). In fat, they were of 6.0 (3.67), and 2.8 (4.65) nmol/mg of protein, respectively (P = 0.0118). Patients with a mixed HALS form had a median plasma uridine level of 4.0 (IC95%: 3.40–4.80) whereas in those with isolated lipoatrophy it was 3.25 (2.55–4.15) µmol/l/l (P = 0.0066). The expression of uridine cytidine kinase and uridine phosphorylase genes was significantly decreased in all groups of patients with respect to controls. A higher expression of the mRNAs for concentrative nucleoside transporters was found in HIV-1-infected patients with respect to healthy controls. Conclusions HIV-1 infection is associated with a decrease in plasma uridine and a shift of uridine to the adipose tissue compartment. Antiretroviral therapy was not associated with plasma uridine concentrations, but pure lipoatrophic HALS was associated with significantly lower plasma uridine concentrations. PMID:21085568

Plasma cortisol and 11-ketotestosterone enzyme immunoassay (EIA) kit validation for three fish species: the orange clownfish Amphiprion percula, the orangefin anemonefish Amphiprion chrysopterus and the blacktip reef shark Carcharhinus melanopterus.

PubMed

Mills, S C; Mourier, J; Galzin, R

2010-08-01

Commercially available enzyme immunoassay (EIA) kits were validated for measuring steroid hormone concentrations in blood plasma from three fish species: the orange clownfish Amphiprion percula, the orangefin anemonefish Amphiprion chrysopterus and the blacktip reef shark Carcharhinus melanopterus. A minimum of 5 microl plasma was required to estimate hormone concentrations with both kits. These EIA kits are a simple method requiring minimal equipment, for measuring hormone profiles under field conditions.

Pharmacokinetics of taurolidine following repeated intravenous infusions measured by HPLC-ESI-MS/MS of the derivatives taurultame and taurinamide in glioblastoma patients.

PubMed

Stendel, Ruediger; Scheurer, Louis; Schlatterer, Kathrin; Stalder, Urs; Pfirrmann, Rolf W; Fiss, Ingo; Möhler, Hanns; Bigler, Laurent

2007-01-01

Taurolidine is known to have antimicrobial activity. Furthermore, at lower concentrations, it has been found to exert a selective antineoplastic effect in vitro and in vivo. The aim of this study was to investigate the pharmacokinetics of taurolidine in vivo following repeated intravenous infusion in a schedule used for the treatment of glioblastoma. As a prerequisite, the pharmacokinetics of taurolidine in human blood plasma and whole blood in vitro was investigated. The pharmacokinetics of taurolidine and its derivatives taurultame and taurinamide were investigated in human blood plasma and in whole blood in vitro using blood from a healthy male volunteer. During repeated intravenous infusion therapy with taurolidine, plasma samples were taken every hour for a period of 13 hours per day in seven patients (three male, four female; mean age 48.4 +/- 12.8 years, range 27-66 years) with a glioblastoma. Following dansyl derivatisation, the concentrations of taurultame and taurinamide were determined using a new method based on high-performance liquid chromatography (HPLC) online coupled to electrospray ionisation tandem mass spectrometry (ESI-MS/MS) in the multiple reaction monitoring mode. Under the experimental conditions used, taurolidine could not be determined directly and was back-calculated from the taurultame and taurinamide values. The new HPLC-ESI-MS/MS method demonstrated high accuracy and reproducibility. In vitro plasma concentrations of taurultame and taurinamide remained constant over the incubation period. In whole blood in vitro, a time-dependent formation of taurinamide was observed. At the start of the incubation, the taurultame-taurinamide ratio (TTR) was 0.95 at an initial taurolidine concentration of 50 microg/mL, and 1.69 at 100 microg/mL. The concentration of taurultame decreased at the same rate as the taurinamide concentration increased, showing logarithmic kinetics. The calculated taurolidine concentration remained largely constant over the 6-hour incubation period. During repeated infusions in patients, calculated plasma concentrations of taurolidine showed a strong increase after the start of each infusion and continued to increase until the end of infusion, followed by a rapid decline. The TTR was found to fluctuate between 0.1 and 0.3, depending on the relation to the previous or next infusion period. The volume of distribution was markedly higher for taurolidine, taurultame and taurinamide than the plasma volume. Taurolidine displayed a stable pattern of derivatives in plasma in vitro, whereas in whole blood, a time- and concentration-dependent conversion was apparent. In patients, the calculated average taurolidine plasma concentration, achieved with the repeated infusion regimen, was in the antineoplastic-effective concentration range. The tissue concentrations of taurolidine and taurultame are expected to be higher than the plasma concentrations, taking into account the calculated volumes of distribution. Repeated infusion of taurolidine is the therapeutically adequate mode of administration for the indication of glioblastoma.

Association of plasma endotoxin, inflammatory cytokines and risk of colorectal adenomas

PubMed Central

2013-01-01

Background Recent studies suggest that bacterial endotoxins may be associated with various chronic diseases, including colorectal adenomas and cancer. Given the evidence linking inflammation and colorectal cancer, we sought to determine if plasma endotoxin concentrations are associated with indicators of systemic or local inflammation and colorectal adenomas. Methods This cross-sectional study consisted of participants who underwent screening colonoscopies and included adenoma cases (n=138) and non-adenoma controls (n=324). Plasma concentrations of endotoxin were measured with Limulus Amebocyte Lysate (LAL) assay. We quantified concentrations of inflammatory cytokines, interleukin-4 (IL-4), IL-6, IL-8, IL-10, IL-12, tumor necrosis factor-alpha (TNF-α), and interferon-γ (IFN-γ) in plasma by ELISA and mRNA expression levels in rectal mucosal biopsies by quantitative RT-PCR. Interleukin-17 was evaluated only in the rectal mucosa. Results Compared to subjects with low plasma endotoxin concentrations, those with higher concentrations were more likely to have adenomas (OR 1.4, 95% CI 1.0-2.1). Among subjects with adenomas, those with villous histology were more likely to have higher endotoxin concentrations (5.4 vs. 4.1EU/mL, p=0.05) and lower plasma IFN-γ (0 vs. 1.64 pg/mL, p=0.02) compared to those with only tubular adenomas. Cases showed a trend of having higher plasma TNF-α levels than controls (p=0.06), but none of the other plasma or rectal mucosal cytokine levels differed between cases and controls. Elevated mucosal IL-12 levels were associated with having multiple adenomas (p=0.04). Higher concentrations of plasma endotoxin predicted increased plasma IL-12 levels (OR 1.5, 95% CI 1.0-2.2) and rectal mucosal IL-12 (OR 1.9, 95% CI 1.0-3.7) and IL-17 gene expression (OR 2.2, 95% CI 1.0-4.6). Conclusions These findings suggest that interactions between elevated plasma endotoxin concentrations and inflammatory cytokines may be relevant to the development of colorectal adenomas. PMID:23442743

Reliability of the Lactate Scout point-of-care instrument for the determination of blood L-lactate concentration in sheep.

PubMed

Kaynar, Ozgur; Karapinar, Tolga; Hayirli, Armagan; Baydar, Ersoy

2015-12-01

Data on accuracy and precision of the Lactate Scout point-of-care (POC) analyzer in ovine medicine are lacking. The purpose of the study was to assess the reliability of the Lactate Scout in sheep. Fifty-seven sheep at varying ages with various diseases were included. Blood lactate concentration in samples collected from the jugular vein was measured immediately on the Lactate Scout. Plasma L-lactate concentration was measured by the Cobas autoanalyzer as the reference method. Data were subjected to Student's t-test, Passing-Bablok regression, and Bland-Altman plot analyses for comparison and assessment of accuracy, precision, and reliability. Plasma l-lactate concentration was consistently lower than blood L-lactate concentration (3.06 ± 0.24 vs 3.3 ± 0.3 mmol/L, P < .0001). There was a positive correlation between plasma and blood L-lactate concentrations (r = .98, P < .0001). The Lactate Scout had 99% accuracy and 98% precision with the reference method. Blood (Y) and plasma (X) L-lactate concentrations were fitted to Y = 0.28 + 1.00 · X, with a residual standard deviation of 0.31 and a negligible deviation from the identity line (P = .93). The bias was fitted to Y = 0.10 + 0.05 · X, with Sy.x of 0.44 (P < .07). The Lactate Scout has high accuracy and precision, with a negligible bias. It is a reliable POC analyzer to assess L-lactate concentration in ovine medicine. © 2015 American Society for Veterinary Clinical Pathology.

Pharmacokinetics of aniracetam and its metabolites in rats.

PubMed

Ogiso, T; Iwaki, M; Tanino, T; Ikeda, K; Paku, T; Horibe, Y; Suzuki, H

1998-05-01

The pharmacokinetics of aniracetam (AP), a new cognitive performance enhancer, and its main metabolites was investigated after intravenous (iv) and oral administrations to rat. The plasma levels of AP, 4-p-anisamidobutyric acid (ABA), and p-anisic acid (AA) were determined simultaneously by the HPLC method. The plasma concentrations of the parent drug and ABA quickly declined in a biexponential manner, with rapid terminal decay and a small mean residence time. However, AA yielded nonlinearly high levels at the initial times and the plasma concentrations of 2-pyrrolidinone (PD) were sustained over a relatively long time. When AA was administered intravenously, nonlinearity of the plasma concentrations was also found at higher doses. To describe the time course of the plasma levels of AP and its metabolites after iv administration, a pharmacokinetic model with seven compartments was applied, which included 10 first-order rate constants and one Michaelis-Menten constant. An approximate fit was obtained between the observed and calculated curves based on the model, except for the plasma concentrations of ABA. The plasma concentration-time profiles of AP and its metabolites following oral administration of AP (50 and 100 mg/kg) were similar to those after iv dosing, with the exception of PD, which showed much lower plasma levels than those after iv administration. Elimination of AP and ABA was rapid after oral dosing, and the bioavailability of AP was extremely small (11.4 and 8.6%). As a result, AP was largely metabolized to ABA, AA, and PD in rat.

The relationship between plasma concentration of metoprolol and CYP2D6 genotype in patients with ischemic heart disease.

PubMed

Wojtczak, Anna; Wojtczak, Maciej; Skrętkowicz, Jadwiga

2014-06-01

Metoprolol is the one of the most commonly used β-blockers in the treatment of ischemic heart disease and it is extensively metabolized in the liver undergoing oxidation by CYP2D6 isoenzyme of cytochrome P450. Gene encoding the CYP2D6 enzyme is characterized by genetic polymorphism. The CYP2D6 oxidation polymorphism has a major impact on the effectiveness and safety of the treatment. The aim of the study was to evaluate the relationship between plasma concentration of metoprolol and the CYP2D6 genotype in patients with ischemic heart disease. Fifty patients were interviewed and subsequently enrolled into the study. The patients received metoprolol twice daily at a dose of 50mg. The blood samples were analyzed for two major defective alleles for CYP2D6 - CYP2D6*4 and CYP2D6*3--by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Metoprolol concentration in plasma was determined by using the new and unique high-performance liquid chromatography (HPLC) method in the author's own modification with Corona CAD detector (Charged Aerosol Detection). In the test group, genotypes conditioning poor oxidation (PM) occurred in 3 patients (6%), while 47 patients (94%) had genotypes coding for extensive metabolism (EM). Patients with PM genotypes had significantly higher plasma concentrations of metoprolol than the patients with EM genotype (mean 92.25 ± SD 36.78 ng/ml vs. mean 168.22 ± SD 5.61 ng/ml, respectively). Established relationships were statistically significant (NIR test, p=0.0009). This study demonstrated that the CYP2D6 genotype remains a major determinant of the metoprolol plasma concentrations. The pharmacogenetic effect is likely to have consequences on both, the clinical benefit of metoprolol treatment and adverse drug reactions. The use of Corona CAD detector seems to be a very good alternative method for the determination of metoprolol concentration in plasma. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Isolation of Biologically Active Exosomes from Plasma of Patients with Cancer.

PubMed

Hong, Chang-Sook; Funk, Sonja; Whiteside, Theresa L

2017-01-01

A method for exosome isolation from human plasma was developed for rapid, high-throughput processing of plasma specimens obtained from patients with cancer. This method removes the bulk of plasma proteins associated with exosomes and can be used for comparative examinations of exosomes and their content in serial specimens of patients' plasma, allowing for monitoring changes in exosome numbers, profiles, and functions in the course of cancer progression or during therapy. The plasma-derived exosomes can be recovered in quantities sufficient for the characterization of their morphology by transmission electron microscopy (TEM), size and concentration by qNano, protein/lipid ratios, nucleic acid extraction, molecular profiling by Western blots or immune arrays, and functional assays.

Comparison of point-of-care methods for preparation of platelet concentrate (platelet-rich plasma).

PubMed

Weibrich, Gernot; Kleis, Wilfried K G; Streckbein, Philipp; Moergel, Maximilian; Hitzler, Walter E; Hafner, Gerd

2012-01-01

This study analyzed the concentrations of platelets and growth factors in platelet-rich plasma (PRP), which are likely to depend on the method used for its production. The cellular composition and growth factor content of platelet concentrates (platelet-rich plasma) produced by six different procedures were quantitatively analyzed and compared. Platelet and leukocyte counts were determined on an automatic cell counter, and analysis of growth factors was performed using enzyme-linked immunosorbent assay. The principal differences between the analyzed PRP production methods (blood bank method of intermittent flow centrifuge system/platelet apheresis and by the five point-of-care methods) and the resulting platelet concentrates were evaluated with regard to resulting platelet, leukocyte, and growth factor levels. The platelet counts in both whole blood and PRP were generally higher in women than in men; no differences were observed with regard to age. Statistical analysis of platelet-derived growth factor AB (PDGF-AB) and transforming growth factor β1 (TGF-β1) showed no differences with regard to age or gender. Platelet counts and TGF-β1 concentration correlated closely, as did platelet counts and PDGF-AB levels. There were only rare correlations between leukocyte counts and PDGF-AB levels, but comparison of leukocyte counts and PDGF-AB levels demonstrated certain parallel tendencies. TGF-β1 levels derive in substantial part from platelets and emphasize the role of leukocytes, in addition to that of platelets, as a source of growth factors in PRP. All methods of producing PRP showed high variability in platelet counts and growth factor levels. The highest growth factor levels were found in the PRP prepared using the Platelet Concentrate Collection System manufactured by Biomet 3i.

Method for plasma formation for extreme ultraviolet lithography-theta pinch

DOEpatents

Hassanein, Ahmed [Naperville, IL; Konkashbaev, Isak [Bolingbrook, IL; Rice, Bryan [Hillsboro, OR

2007-02-20

A device and method for generating extremely short-wave ultraviolet electromagnetic wave, utilizing a theta pinch plasma generator to produce electromagnetic radiation in the range of 10 to 20 nm. The device comprises an axially aligned open-ended pinch chamber defining a plasma zone adapted to contain a plasma generating gas within the plasma zone; a means for generating a magnetic field radially outward of the open-ended pinch chamber to produce a discharge plasma from the plasma generating gas, thereby producing a electromagnetic wave in the extreme ultraviolet range; a collecting means in optical communication with the pinch chamber to collect the electromagnetic radiation; and focusing means in optical communication with the collecting means to concentrate the electromagnetic radiation.

Determination of benzocaine in rainbow trout plasma

USGS Publications Warehouse

Bernardy, Jeffery A.; Coleman, K.S.; Stehly, G.R.; Gingerich, William H.

1996-01-01

A liquid chromatographic method is described for analysis of benzocaine (BZ), a proposed fish anesthetic, in rainbow trout plasma, Mean recoveries of BZ from plasma samples fortified at 44-10 100 ng/mL were 96-100%. The method detection limit is 10 ng/mL, and the limit of quantitation is 37 ng/mL. Acetylation of BZ occurs in whole blood after storage at room temperature (i.e., 21 degrees C) for 10 min. However, no acetylation of BZ was detected in plasma samples held at room temperature for 4 h, Mean method precision for plasma samples with incurred BZ residue is similar to that for fortified samples in the same concentration range (relative standard deviations of 0.9 and 1.2%, respectively).

A novel freeze-dried storage and preparation method for the determination of mycophenolic acid in plasma by high-performance liquid chromatography.

PubMed

Wang, Lei; Qiang, Wei; Li, Ying; Cheng, Zeneng; Xie, Mengmeng

2017-09-01

Plasma samples were conventionally stored at freezing conditions until the time of detection. Such a technique, when carried out over an extended period, is energy consuming; in addition, preparation and transportation of stored samples is inconvenient. In this study, a freeze-dried storage and preparation method was proposed to determine the presence of mycophenolic acid (MPA) in plasma. Fresh plasma samples were freeze-dried using a device, and then stored at ambient temperature. After the stored samples were soaked with methanol spiked with the internal standard, high-performance liquid chromatography was conducted to detect MPA. The proposed method was demonstrated to be precise and accurate over the linear range of 0.5-50 μg mL -1 , with both intra- and inter-day precision being <7% and biases <10%. The freeze-dried samples were stable at ambient temperature for at least 40 days. This method was also successfully applied to the pharmacokinetic study of MPA in healthy volunteers. Pharmacokinetic parameters, such as maximum plasma concentration, time point of maximum plasma concentration and elimination half-life, among others, were consistent with the results in the published study. This proposed technique was proved to be simple, reproducible and energy saving. This approach could also simplify the storage and analysis of samples in clinical and scientific drug research. Copyright © 2017 John Wiley & Sons, Ltd.

Stereoselective binding of doxazosin enantiomers to plasma proteins from rats, dogs and humans in vitro

PubMed Central

Sun, Jia-an; Kong, De-zhi; Zhen, Ya-qin; Li, Qing; Zhang, Wei; Zhang, Jiang-hua; Yin, Zhi-wei; Ren, Lei-ming

2013-01-01

Aim: (±)Doxazosin is a long-lasting inhibitor of α1-adrenoceptors that is widely used to treat benign prostatic hyperplasia and lower urinary tract symptoms. In this study we investigated the stereoselective binding of doxazosin enantiomers to the plasma proteins of rats, dogs and humans in vitro. Methods: Human, dog and rat plasma were prepared. Equilibrium dialysis was used to determine the plasma protein binding of each enantiomer in vitro. Chiral HPLC with fluorescence detection was used to measure the drug concentrations on each side of the dialysis membrane bag. Results: Both the enantiomers were highly bound to the plasma proteins of rats, dogs and humans [(−)doxazosin: 89.4%–94.3%; (+)doxazosin: 90.9%–95.4%]. (+)Doxazosin exhibited significantly higher protein binding capacities than (−)doxazosin in all the three species, and the difference in the bound concentration (Cb) between the two enantiomers was enhanced as their concentrations were increased. Although the percentage of the plasma protein binding in the dog plasma was significantly lower than that in the human plasma at 400 and 800 ng/mL, the corrected percentage of plasma protein binding was dog>human>rat. Conclusion: (−)Doxazosin and (+)doxazosin show stereoselective plasma protein binding with a significant species difference among rats, dogs and humans. PMID:24241343

Determination of methylglyoxal in human blood plasma using fluorescence high performance liquid chromatography after derivatization with 1,2-diamino-4,5-methylenedioxybenzene.

PubMed

Ogasawara, Yuki; Tanaka, Ryo; Koike, Shin; Horiuchi, Yasue; Miyashita, Mitsuhiro; Arai, Makoto

2016-09-01

Methylglyoxal (MG) is a highly reactive dicarbonyl compound that promotes the non-enzymatic glycation of proteins to yield irreversible advanced glycated end products, leading to the cross-linking or degradation of proteins. The physiological relevance of MG currently remains unclear because its metabolic behavior has not yet been elucidated in detail. Although several labeling methods that require a HPLC system have been developed and used to measure MG, a standard method to analyze the content of MG in biological samples has not been established. We herein present a practical method based on HPLC with fluorescence detection to measure low MG levels. MG concentrations were also measured in human blood plasma using the present method in order to demonstrate its utility. A calibration curve was produced using freshly purified MG at concentrations ranging between 0.05 and 1.0μM. The intra-day and inter-day relative standard diviations of the method were 2.55% and 4.03%, respectively. The limit of detection and limit of quantification were 60fmol and 200fmol, respectively for MG with a 10-μl injection volume of the derivatized sample solution. When the optimized method was applied to human plasma, the resulting concentrations of MG in the plasma of healthy subjects (n=23) ranged between 0.024 and 0.258μM (mean±SD=0.098±0.066). Thus, the method developed herein is simple, sensitive, and easy to operate for the measurement of MG in biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of a sensitive LC-MS/MS method for the determination of fenoterol in human plasma and urine samples.

PubMed

Sanghvi, M; Ramamoorthy, A; Strait, J; Wainer, I W; Moaddel, R

2013-08-15

Due to the lack of sensitivity in current methods for the determination of fenoterol (Fen), a rapid LC-MS/MS method was developed for the determination of (R,R')-Fen and (R,R';S,S')-Fen in plasma and urine. The method was fully validated and was linear from 50pg/ml to 2000pg/ml for plasma and from 2.500ng/ml to 160ng/ml for urine with a lower limit of quantitation of 52.8pg/ml in plasma. The coefficient of variation was <15% for the high QC standards and <10% for the low QC standards in plasma and was <15% for the high and low QC standards in urine. The relative concentrations of (R,R')-Fen and (S,S')-Fen were determined using a chirobiotic T chiral stationary phase. The method was used to determine the concentration of (R,R')-Fen in plasma and urine samples obtained in an oral cross-over study of (R,R')-Fen and (R,R';S,S')-Fen formulations. The results demonstrated a potential pre-systemic enantioselective interaction in which the (S,S')-Fen reduces the sulfation of the active (R,R')-Fen. The data suggest that a non-racemic mixture of the Fen enantiomers may provide better bioavailability of the active (R,R')-Fen for use in the treatment of cardiovascular disease. Published by Elsevier B.V.

Plasma Deactivation of Oral Bacteria Seeded on Hydroxyapatite Disks as Tooth Enamel Analogue

PubMed Central

Blumhagen, Adam; Singh, Prashant; Mustapha, Azlin; Chen, Meng; Wang, Yong; Yu, Qingsong

2014-01-01

Purpose To study the plasma treatment effects on deactivation of oral bacteria seeded on a tooth enamel analogue. Methods A non-thermal atmospheric pressure argon plasma brush was used to treat two different Gram-positive oral bacteria including Lactobacillus acidophilus (L. acidophilus) and Streptococcus mutans (S. mutans). The bacteria were seeded on hydroxyapatite (HA) disks used as tooth enamel analogue with three initial bacterial seeding concentrations: a low inoculum concentration between 2.1×108 and 2.4×108 cfu/mL, a medium inoculum concentration between 9.8×108 and 2.4×109 cfu/mL, and a high inoculum concentration between 1.7×1010 and 3.5×1010 cfu/mL. The bacterial survivability upon plasma exposure was examined in terms of plasma exposure time and oxygen addition into the plasmas. SEM was performed to examine bacterial morphological changes after plasma exposure. Results The experimental data indicated that 13 second plasma exposure time completely killed all the bacteria when initial bacterial seeding density on HA surfaces were less than 6.9×106 cfu/cm2 for L. acidophilus and 1.7×107 cfu/cm2 for S. mutans, which were resulted from low initial seeding inoculum concentration between 2.1×108 and 2.4×108 cfu/mL. Plasma exposure of the bacteria at higher initial bacterial seeding density obtained with high initial seeding inoculum concentration, however, only resulted in ~ 1.5 to 2 log reduction and ~ 2 to 2.5 log reduction for L. acidophilus and S. mutans, respectively. It was also noted that oxygen addition into the argon plasma brush did not affect the plasma deactivation effectiveness. SEM images showed that plasma deactivation mainly occurred with the top layer bacteria, while shadowing effects from the resulting bacterial debris reduced the plasma deactivation of the underlying bacteria. Clinical Significance The experimental results indicate that, with direct contact, nonthermal atmospheric pressure argon plasmas could rapidly and effectively deactivate oral bacteria seeded on HA surfaces and thus could be a promising technique in various dental clinical applications. PMID:25000666

The pharmacokinetics of intraosseous atropine in hypovolemic swine.

PubMed

Yost, Jonathan; Baldwin, Phillip; Bellenger, Sarah; Bradshaw, Freida; Causapin, Edna; Demotica, Richelle; Livingston, Michael; Lee, Cynthia; Gegel, Brian; Burgert, James; Claessens, Adam; Johnson, Don; Loughren, Michael

2015-01-01

Compare the pharmacokinetics of atropine administered via the intravenous (IV), intramuscular (IM), and intraosseous (IO) routes in a normovolemic and hypovolemic swine model. Prospective, between subjects, experimental study. Vivarium. Yorkshire-cross swine (N = 36). Atropine was administered via IV, IM, or IO routes to normovolemic and hypovolemic swine. Blood samples were drawn at regular intervals after atropine administration and analyzed for plasma atropine concentration. Pharmacokinetic parameters were obtained from modeling the plasma concentrations. Pharmacokinetic parameters, maximum concentration (Cmax) and time to maximum concentration (Tmax). The IV and IO groups in both the normovolemic and hypovolemic models reached peak plasma concentration immediately and had a very rapid distribution phase with no apparent absorption phase for the IO groups. Peak plasma concentration and time to reach peak concentration were both significantly lower for the IM groups. There was a significant increase in absorption time with IM administration in the hypovolemic model compared to the normovolemic model. The IO route is an effective method of administering atropine and is comparable to the IV route even under conditions of significant hemorrhage. Therapeutic levels of atropine may be delayed and possibly difficult to obtain via IM injection in the presence of hypovolemic shock.

Spatial measurement in rotating magnetic field plasma acceleration method by using two-dimensional scanning instrument and thrust stand

NASA Astrophysics Data System (ADS)

Furukawa, T.; Takizawa, K.; Yano, K.; Kuwahara, D.; Shinohara, S.

2018-04-01

A two-dimensional scanning probe instrument has been developed to survey spatial plasma characteristics in our electrodeless plasma acceleration schemes. In particular, diagnostics of plasma parameters, e.g., plasma density, temperature, velocity, and excited magnetic field, are essential for elucidating physical phenomena since we have been concentrating on next generation plasma propulsion methods, e.g., Rotating Magnetic Field plasma acceleration method, by characterizing the plasma performance. Moreover, in order to estimate the thrust performance in our experimental scheme, we have also mounted a thrust stand, which has a target type, on this movable instrument, and scanned the axial profile of the thrust performance in the presence of the external magnetic field generated by using permanent magnets, so as to investigate the plasma captured in a stand area, considering the divergent field lines in the downstream region of a generation antenna. In this paper, we will introduce the novel measurement instrument and describe how to measure these parameters.

New approaches to evaluate sympathoadrenal system activity in experiments on Earth and in space

NASA Astrophysics Data System (ADS)

Kvetnansky, R.; Noskov, V. B.; Blazicek, P.; Macho, L.; Grigoriev, A. I.; Goldstein, D. S.; Kopin, I. J.

In previous studies the activity of the sympathoadrenal system (SAS) in cosmonauts during space flights was evaluated by measuring plasma catecholamines (CA) levels and urinary CA and their metabolites concentrations. Plasma CA levels are accepted indicators of SAS activity, however, they are determined by the plasma clearances as well as the rates of CA release (spillover-SO) into the bloodstream. Nowadays methods are available which evaluate not only plasma levels of CA but also their release, spillover, uptake, reuptake, degradation and also CA synthesis in vivo measured by plasma levels of dihydroxyphenylalanine (DOPA). Plasma concentrations of DOPA, the CA noradrenaline (NE), adrenaline (ADR), and dopamine (DA), the deaminated catechol metabolites dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC), and the O-methylated metabolites methoxyhydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were measured during immobilization stress (IMO) in conscious rats. Radiotracer methods were used to measure NE SO. IMO markedly increased arterial NE levels but NE SO was less elevated bacause the NE clearance was slightly reduced in IMO rats. Simultaneous measurements of plasma CA and their metabolites provide another means to obtain information about SAS function. For instance, dissociation between changes of plasma DHPG and NE levels can indicate changes in neuronal reuptake of NE. We found marked parallel increases in plasma NE and DHPG levels during acute IMO; however after repeated IMO, plasma NE levels were increased but DHPG responses were less pronounced suggesting a reduced NE reuptake. DOPA, the CA precursor, circulates in plasma at a concentration higher than NE. During stress, increased sympathoneural outflow stimulates DOPA synthesis and release into the circulation supporting the view that changes in plasma DOPA levels during stress reflect in vivo changes in the rate of CA synthesis. We propose to measure the new plasma indicators of SAS activity in cosmonauts and/or in animals before, during and after space flights.

Clinical Chorioamnionitis IV: the Maternal Plasma Cytokine Profile

PubMed Central

Romero, Roberto; Chaemsaithong, Piya; Docheva, Nikolina; Korzeniewski, Steven J.; Tarca, Adi L.; Bhatti, Gaurav; Xu, Zhonghui; Kusanovic, Juan P.; Dong, Zhong; Ahmed, Ahmed I.; Yoon, Bo Hyun; Hassan, Sonia S.; Chaiworapongsa, Tinnakorn; Yeo, Lami

2017-01-01

Introduction Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation. Methods A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid cultures, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentrations: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%. Results 1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that the fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response. Conclusions 1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis. PMID:26352068

Ultra-high performance liquid chromatography tandem mass spectrometric method for the determination of tamoxifen, N-desmethyltamoxifen, 4-hydroxytamoxifen and endoxifen in dried blood spots--development, validation and clinical application during breast cancer adjuvant therapy.

PubMed

Antunes, Marina Venzon; Raymundo, Suziane; de Oliveira, Vanessa; Staudt, Dilana Elisabeth; Gössling, Gustavo; Peteffi, Giovana Piva; Biazús, Jorge Villanova; Cavalheiro, José Antônio; Tre-Hardy, Marie; Capron, Arnaud; Haufroid, Vincent; Wallemacq, Pierre; Schwartsmann, Gilberto; Linden, Rafael

2015-01-01

A LC-MSMS method for the simultaneous determination of tamoxifen, N-desmethyltamoxifen, 4-hydroxytamoxifen and endoxifen in dried blood spots samples was developed and validated. The method employs an ultrasound-assisted liquid extraction and a reversed phase separation in an Acquity(®) C18 column (150×2.1 mm, 1.7 µm). Mobile phase was a mixture of formic acid 0.1% (v/v) pH 2.7 and acetonitrile (gradient from 60:40 to 50:50, v/v). Total analytical run time was 8 min. Precision assays showed CV % lower than 10.75% and accuracy in the range 94.5 to 110.3%. Mean analytes recoveries from DBS ranged from 40% to 92%. The method was successfully applied to 91 paired clinical DBS and plasma samples. Dried blood spots concentrations were highly correlated to plasma, with rs>0.83 (P<0.01). Median estimated plasma concentrations after hematocrit and partition factor adjustment were: TAM 123.3 ng mL(-1); NDT 267.9 ng mL(-1), EDF 10.0 ng mL(-1) and HTF 1.3 ng mL(-1,) representing in average 98 to 104% of the actually measured concentrations. The DBS method was able to identify 96% of patients with plasma EDF concentrations below the clinical threshold related to better prognosis (5.9 ng mL(-1)). The procedure has adequate analytical performance and can be an efficient tool to optimize adjuvant breast cancer treatment, especially in resource limited settings. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous stable-isotope dilution GC-MS measurement of homoarginine, guanidinoacetate and their common precursor arginine in plasma and their interrelationships in healthy and diseased humans.

PubMed

Hanff, Erik; Kayacelebi, Arslan Arinc; Yanchev, Georgi Radoslavov; Maassen, Norbert; Haghikia, Arash; Tsikas, Dimitrios

2016-03-01

Low concentrations of L-homoarginine (hArg) in plasma or serum and urine have recently emerged as a novel cardiovascular risk factor. Previously, we reported gas chromatography-mass spectrometry (GC-MS) and GC-tandem MS (GC-MS/MS) methods for the quantitative determination of hArg and Arg in plasma, serum, urine and other biological samples. In these methods, plasma and serum are ultrafiltered by means of commercially available cartridges (10 kDa), and 10-µL ultrafiltrate aliquots are subjected to a two-step derivatization procedure, yielding the methyl ester tri(N-pentafluoropropionyl) derivatives. De novo prepared trideuteromethyl ester hArg (d3Me-hArg) was used as an internal standard. To make the hArg analysis in plasma more convenient, straightforward and cheaper we performed two key modifications: (1) precipitation of plasma proteins by methanol and (2) use of newly prepared and d3Me-hArg as the internal standard. The method was validated and used for the quantitative determination of hArg in human plasma by GC-MS after electron-capture negative-ion chemical ionization (ECNICI) using methane as the reactant gas. Intra-assay accuracy (recovery) and imprecision (relative standard deviation) were within generally accepted ranges (93-109 and 2.3-10 %, respectively). Furthermore, we extended the applicability of this method to guanidinoacetate (GAA). This is of particular importance because hArg and GAA are produced from Arg by the catalytic action of arginine:glycine amidinotransferase (AGAT) also known as glycine:arginine transamidinase (GATM). Using this method, we quantitated simultaneously hArg, Arg and GAA in the selected-ion monitoring mode in 10-µL aliquots of plasma. In plasma samples of 17 non-medicated healthy young men, the concentration of hArg, GAA and Arg was determined to be (mean ± SD) 1.7 ± 0.6, 2.6 ± 0.8, 91 ± 29 µM, respectively. The correlation between hArg and Arg was borderline (r = 0.47, P = 0.06). GAA strongly correlated with Arg (r = 0.82, P < 0.0001) but did not correlate with hArg (r = 0.17, P = 0.52). The plasma concentrations of hArg, GAA and Arg measured in 9 patients suffering from stroke or transitory ischemic attack were 1.8 ± 0.6, 2.7 ± 0.4 and 82 ± 17 µM. The ratio values of the hArg, GAA and Arg concentrations measured after removal of plasma proteins by methanol precipitation or ultrafiltration were 0.94 ± 0.1, 0.94 ± 0.08, and 0.88 ± 0.07, respectively. Simultaneous measurement of hArg and GAA in human plasma may allow assessment of AGAT activity in vivo with respect both to GAA and to hArg and their relationship in health, disease, nutrition and pharmacotherapy.

Novel UHPLC-MS/MS method for the determination of rotigotine in the plasma of patients with Parkinson's disease.

PubMed

Mohamed, Susan; Riva, Roberto; Contin, Manuela

2017-09-01

A novel ultra-high-pressure liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of the dopamine receptor agonist rotigotine in human plasma. Following liquid-liquid extraction with tert-butyl methyl ether from 500 μL plasma, the chromatographic analysis was performed on a Gemini NX3 column using 5 mm pH 5.0 ammonium acetate-5 mm ammonium acetate in methanol as binary gradient mobile phase, at a flow rate of 0.3 mL/min. The MS/MS ion transitions were 316.00 → 147.00 for rotigotine and 256.10 → 211.00 for the internal standard (lamotrigine). The lower limit of quantitation was 50 pg/mL and the linearity was determined from 50 to 2500 pg/mL. The mean recovery was 96.9%. Both intra- and interassay imprecision and inaccuracy were ≤15% at all quality control concentrations. The method was successfully applied to measure morning trough plasma rotigotine concentrations in a series of patients with Parkinson's disease on chronic treatment. The present study describes the first fully validated method for rotigotine determination in human plasma. Copyright © 2017 John Wiley & Sons, Ltd.

Quantitation of N-ethyl-3,4-methylenedioxyamphetamine and its major metabolites in human plasma by high-performance liquid chromatography and fluorescence detection.

PubMed

Brunnenberg, M; Lindenblatt, H; Gouzoulis-Mayfrank, E; Kovar, K A

1998-11-20

A HPLC method has been developed for the analogue of Ecstasy MDE and its major metabolites N-ethyl-4-hydroxy-3-methoxyamphetamine (HME) and 3,4-methylenedioxyamphetamine (MDA) in human plasma. In the course of our investigations we found that the methylenedioxyamphetamines and HME exhibit fluorescence at 322 nm. Therefore the detection could be carried out with a fluorescence (FL) detector. Solid-phase extraction was used for sample preparation and yielded high recovery rates greater than 95%. The limit of quantitation for MDE and its metabolites in the extracts was between 1.5 and 8.9 ng/ml and the method standard deviations were less than 5%. This sensitive, rapid and reliable analytical method has been used successfully in the quantitation of the substances in plasma samples obtained from 14 volunteers in two clinical studies after p.o. administration of 100 to 140 mg MDE*HCI. The maximum plasma concentrations were 235-465 ng/ml (MDE), 67-673 ng/ml (HME) and 7-33 ng/ml (MDA), respectively. Pharmacokinetic parameters have been investigated using the plasma concentration curves.

Genome-Wide Meta-Analyses of Plasma Renin Activity and Concentration Reveal Association with the Kininogen 1 and Prekallikrein Genes

PubMed Central

Lieb, Wolfgang; Chen, Ming-Huei; Teumer, Alexander; de Boer, Rudolf A.; Lin, Honghuang; Fox, Ervin R.; Musani, Solomon K.; Wilson, James G.; Wang, Thomas J.; Völzke, Henry; Petersen, Ann-Kristin; Meisinger, Christine; Nauck, Matthias; Schlesinger, Sabrina; Li, Yong; Menard, Jöel; Hercberg, Serge; Wichmann, H.-Erich; Völker, Uwe; Rawal, Rajesh; Bidlingmaier, Martin; Hannemann, Anke; Dörr, Marcus; Rettig, Rainer; van Gilst, Wiek H.; van Veldhuisen, Dirk J.; Bakker, Stephan J.L.; Navis, Gerjan; Wallaschofski, Henri; Meneton, Pierre; van der Harst, Pim; Reincke, Martin; Vasan, Ramachandran S.; Consortium, CKDGen

2015-01-01

Background The renin-angiotensin-aldosterone-system (RAAS) is critical for regulation of blood pressure and fluid balance and influences cardiovascular remodeling. Dysregulation of the RAAS contributes to cardiovascular and renal morbidity. The genetic architecture of circulating RAAS components is incompletely understood. Methods and Results We meta-analyzed genome-wide association data for plasma renin activity (n=5,275), plasma renin concentrations (n=8,014) and circulating aldosterone (n=13,289) from up to four population-based cohorts of European and European-American ancestry, and assessed replication of the top results in an independent sample (n=6,487). Single nucleotide polymorphisms (SNPs) in two independent loci displayed associations with plasma renin activity atgenome-wide significance (p<5×10-8). A third locus was close to this threshold (rs4253311 in kallikrein B [KLKB1], p=5.5×10-8). Two of these loci replicated in an independent sample for both plasma renin and aldosterone concentrations (SNP rs5030062 in kininogen 1 [KNG1]: p=0.001 for plasma renin, p=0.024 for plasma aldosterone concentration; rs4253311 with p<0.001 for both plasma renin and aldosterone concentration). SNPs in the NEBL gene reached genome-wide significance for plasma renin concentration in the discovery sample (top SNP rs3915911, p= 8.81×10-9), but did not replicate (p=0.81). No locus reached genome-wide significance for aldosterone. SNPs rs5030062 and rs4253311 were not related to blood pressure or renal traits; in a companion study, variants in the kallikrein B locus were associated with B-type natriuretic peptide concentrations in African-Americans. Conclusions We identified two genetic loci (kininogen 1 and kallikrein B) influencing key components of the RAAS, consistent with the close interrelation between the kallikrein-kinin system and the RAAS. PMID:25477429

Effectiveness of a flow-based device using riboflavin photochemistry in damaging blood-borne viral nucleic acids.

PubMed

Zhu, Liguo; Tong, Hongli; Wang, Shufang; Yu, Yang; Liu, Zhong; Li, Changqing; Wang, Deqing

2018-05-03

Effectiveness of a flow-based treatment device using riboflavin photochemistry was demonstrated by cytopathic effect method using indicator viruses. However, inactivation efficacy against real blood-borne viruses needs to be evaluated, especially at nucleic acid level. Special plasma samples with varying concentrations of blood-borne virus were selected using a strict blood selection procedure and were treated with device treatment (DT). Nucleic acid test (NAT) using polymerase chain reaction fluorescence method was used to detect virus copies. The NAT value of 4325 in plasma with high Hepatitis B Virus (HBV) concentrations decreased to 1330 with DT. After 100-fold dilution, the NAT value was below the NAT detection limits with DT compared with 23.0 that without DT. The NAT value of 61.9 in plasma with medium HBV concentrations decreased to 37.8 with DT, and after 10-fold dilution, the NAT value was below the NAT detection limits with DT compared with below 20 that without DT. The Ct values of plasma with low concentrations of blood-borne viruses were below the NAT detection limits with DT. There was a dose effect with DT which was effective in blood-borne viruses damaging nucleic acids to a level below the NAT detection limits. Copyright © 2018 Elsevier B.V. All rights reserved.

A simple high performance liquid chromatography method for determination of rebamipide in rat urine.

PubMed

Cooper, Dustin L; Harirforoosh, Sam

2014-01-01

Rebamipide is a mucoprotective agent commonly used to prevent nonsteriodal anti-inflammatory drug-induced gastrointenstinal side effects [1]. Human plasma and urine analysis of rebamipide utilizing high performance liquid chromatography (HPLC) have been reported [2]. Recently, we reported on the plasma levels of rebamipide in presense or absence of celecoxib or diclofenac in rats [3] using a modified HPLC method of detection developed by Jeoung et al. [4]. To tailor the method towards use in urinary rebamipide extraction and analysis, the following modifications were made:•To compensate for high concentrations of rebamipide found in urine, a new rebamipide stock solution was prepared with a final concentration of 50,000 ng/mL.•Rat urine calibration standards were obtained within the range of 50-1000 ng/mL and 1000-50,000 ng/mL.•Plasma samples were replaced with urine samples.

Plasma levels of selenium-containing proteins in Inuit adults from Nunavik.

PubMed

Achouba, Adel; Dumas, Pierre; Ouellet, Nathalie; Lemire, Mélanie; Ayotte, Pierre

2016-11-01

Selenium (Se) is highly abundant in marine foods traditionally consumed by Inuit of Nunavik (Northern Quebec, Canada) and accordingly, their Se intake is among the highest in the world. However, little is known regarding the biological implications of this high Se status in this Arctic indigenous population. We used a method combining affinity chromatography and inductively coupled plasma-mass spectrometry with quantification by post-column isotope dilution to determine total Se levels and concentrations of Se-containing proteins in archived plasma samples of Inuit adults who participated to the 2004 Nunavik Inuit Health Survey (N = 852). Amounts of mercury (Hg) associated with Se-containing proteins were also quantified. Results show that glutathione peroxidase 3 (GPx3), selenoprotein P (SelP) and selenoalbumin (SeAlb) represented respectively 25%, 52% and 23% of total plasma Se concentrations. In addition, small amounts of Hg co-eluted with each Se-containing protein and up to 50% of plasma Hg was associated to SelP. Total plasma Se concentrations (median = 139 μg L− 1; interquartile range (IQR) = 22.7 μg L− 1) were markedly lower and less variable than whole blood Se concentration (median = 261 μg L− 1, IQR = 166 μg L− 1). A non linear relation was observed between whole blood Se and plasma Se levels, with plasma Se concentrations leveling off at approximately 200 μg L− 1, whereas 16% and 3% of individuals exhibited whole blood concentrations higher than 500 μg L− 1 and 1000 μg L− 1, respectively. In contrast, a linear relationship was previously reported in communities consuming Brazil nuts which are rich Se, mainly present as selenomethionine. This suggests that a different selenocompound, possibly selenoneine, is present in the Arctic marine food chain and accumulates in the blood cellular fraction of Inuit.

UV-vis spectroscopy study of plasma-activated water: Dependence of the chemical composition on plasma exposure time and treatment distance

NASA Astrophysics Data System (ADS)

Oh, Jun-Seok; Szili, Endre J.; Ogawa, Kotaro; Short, Robert D.; Ito, Masafumi; Furuta, Hiroshi; Hatta, Akimitsu

2018-01-01

Plasma-activated water (PAW) is receiving much attention in biomedical applications because of its reported potent bactericidal properties. Reactive oxygen and nitrogen species (RONS) that are generated in water upon plasma exposure are thought to be the key components in PAW that destroy bacterial and cancer cells. In addition to developing applications for PAW, it is also necessary to better understand the RONS chemistry in PAW in order to tailor PAW to achieve a specific biological response. With this in mind, we previously developed a UV-vis spectroscopy method using an automated curve fitting routine to quantify the changes in H2O2, NO2 -, NO3 - (the major long-lived RONS in PAW), and O2 concentrations. A major advantage of UV-vis is that it can take multiple measurements during plasma activation. We used the UV-vis procedure to accurately quantify the changes in the concentrations of these RONS and O2 in PAW. However, we have not yet provided an in-depth commentary of how we perform the curve fitting procedure or its implications. Therefore, in this study, we provide greater detail of how we use the curve fitting routine to derive the RONS and O2 concentrations in PAW. PAW was generated by treatment with a helium plasma jet. In addition, we employ UV-vis to study how the plasma jet exposure time and treatment distance affect the RONS chemistry and amount of O2 dissolved in PAW. We show that the plasma jet exposure time principally affects the total RONS concentration, but not the relative ratios of RONS, whereas the treatment distance affects both the total RONS concentration and the relative RONS concentrations.

Stability of hemostatic proteins in canine fresh-frozen plasma thawed with a modified commercial microwave warmer or warm water bath.

PubMed

Pashmakova, Medora B; Barr, James W; Bishop, Micah A

2015-05-01

To compare stability of hemostatic proteins in canine fresh-frozen plasma (FFP) thawed with a modified commercial microwave warmer (MCM) or warm water bath (37°C; WWB) or at room temperature (22°C). Fresh-frozen plasma obtained from 8 canine donors of a commercial blood bank. A commercial microwave warmer was modified with a thermocouple to measure surface temperature of bags containing plasma. The MCM and a WWB were each used to concurrently thaw a 60-mL bag of plasma obtained from the same donor. Two 3-mL control aliquots of FFP from each donor were thawed to room temperature without use of a heating device. Concentrations of hemostatic proteins, albumin, and D-dimers; prothrombin time (PT); and activated partial thromboplastin time (aPTT) were determined for all samples. Significant decreases in concentrations of factors II, IX, X, XI, fibrinogen, von Willebrand factor, antithrombin, protein C, and albumin and significant increases in PT and aPTT were detected for plasma thawed with the MCM, compared with results for samples thawed with the WWB. Concentrations of factors VII, VIII, and XII were not significantly different between plasma thawed with the MCM and WWB. Concentrations of D-dimers were above the reference range for all thawed samples regardless of thawing method. No significant differences in factor concentrations were detected between control and WWB-thawed samples. Significant differences in hemostatic protein concentrations and coagulation times were detected for plasma thawed with an MCM but not between control and WWB-thawed samples. Clinical importance of these changes should be investigated.

Performance Characteristics of Plasma Amyloid β 40 and 42 Assays

PubMed Central

Okereke, Olivia I.; Xia, Weiming; Irizarry, Michael C.; Sun, Xiaoyan; Qiu, Wei Q.; Fagan, Anne M.; Mehta, Pankaj D.; Hyman, Bradley T.; Selkoe, Dennis J.; Grodstein, Francine

2009-01-01

Background Identifying biomarkers of Alzheimer disease (AD) risk will be critical to effective AD prevention. Levels of circulating amyloid β (Aβ) 40 and 42 may be candidate biomarkers. However, properties of plasma Aβ assays must be established. Methods Using five different protocols, blinded samples were used to assess: intra-assay reproducibility; impact of EDTA vs. heparin anticoagulant tubes; and effect of time-to-blood processing. In addition, percent recovery of known Aβ concentrations in spiked samples was assessed. Results Median intra-assay coefficients of variation (CVs) for the assay protocols ranged from 6–24% for Aβ-40, and 8–14% for Aβ-42. There were no systematic differences in reproducibility by collection method. Plasma concentrations of Aβ (particularly Aβ-42) appeared stable in whole blood kept in ice packs and processed as long as 24 hours after collection. Recovery of expected concentrations was modest, ranging from -24% to 44% recovery of Aβ-40, and 17% to 61% of Aβ-42. Conclusions Across five protocols, plasma Aβ-40 and Aβ-42 levels were measured with generally low error, and measurements appeared similar in blood collected in EDTA vs. heparin. While these preliminary findings suggest that measuring plasma Aβ-40 and Aβ-42 may be feasible in varied research settings, additional work in this area is necessary. PMID:19221417

The extraction of plasma 3-hydroxy-17-oxo steroid sulphates and the measurement of the constituent dehydroepiandrosterone sulphate and androsterone sulphate

PubMed Central

McKenna, Jean; Rippon, A. E.

1965-01-01

1. A simple method for the extraction of 17-oxo steroid sulphates of plasma is described; glucosiduronates and orthophosphates are extracted, but to a smaller extent. 2. Four methods of analyses of the extracts are given and are relatively simple. Three of these are specific for steroid sulphates and two measure the sulphate conjugates directly. 3. Values for dehydroepiandrosterone sulphate and androsterone sulphate concentrations of normal and pathological plasmas are given. PMID:14333546

Plasma concentration of ketorolac after local infiltration analgesia in hip arthroplasty.

PubMed

Affas, F; Eksborg, S; Wretenberg, P; Olofsson, C; Stephanson, N; Stiller, C-O

2014-10-01

Local infiltration analgesia (LIA) with local anaesthetic (ropivacaine), a nonsteroidal anti-inflammatory drug (ketorolac) and epinephrine after lower extremity arthroplasty has gained increasing popularity during the last decade. This method has certain advantages, which include minimal systemic side effects, faster post-operative mobilization, earlier post-operative discharge from hospital and less opioid consumption. However, information regarding plasma concentrations of ketorolac after LIA mixture is insufficient to predict the risk of renal impairment in patients subjected to arthroplasty. To determine the maximal plasma concentration and the exposure of ketorolac during the first 30 h following LIA in hip arthroplasty. Thirteen patients scheduled for primary total hip arthroplasty with LIA (ropivacaine 200 mg, ketorolac 30 mg and epinephrine 0.5 mg in a volume of 106 ml) were included. Plasma concentration of ketorolac was quantified by liquid chromatography-mass spectrometry. In addition, we assessed the effect of increasing age and decreasing glomerular filtration rate on the maximal plasma concentration and the total exposure to ketorolac during 30 h. The range of the maximal plasma concentration, 0.3-2.2 mg/l, was detected 30 min-4 h after completing the infiltration. Similar plasma levels have been reported after intramuscular injection of the same dose of ketorolac to healthy elderly volunteers. Exposure to ketorolac after LIA may be comparable to an intramuscular injection of the same dose. Decision of dose reduction should be based on clinical assessment of risk factors. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Spatial characterization of red and white skin potatoes using nano-second laser induced breakdown in air

NASA Astrophysics Data System (ADS)

Rehan, Imran; Rehan, Kamran; Sultana, S.; Haq, M. Oun ul; Niazi, Muhammad Zubair Khan; Muhammad, Riaz

2016-01-01

We presents spectroscopic study of the plasma generated by a Q-switched Nd:YAG (1064 nm) laser irradiation of the flesh of red and white skin potatoes. From the spectra recorded with spectrometer (LIBS2500+, Ocean Optics, USA) 11 elements were identified in red skin potato, whereas, the white skin potato was found to have nine elements. Their relative concentrations were estimated using CF-LIBS method for the plasma in local thermodynamic equilibrium. The target was placed in ambient air at atmospheric pressure. The electron temperature and number density were calculated from Boltzmann plot and stark broadened line profile methods, respectively using Fe I spectral lines. The spatial distribution of plasma parameters were also studied which show a decreasing trend of 6770 K-4266 K and (3-2.0) × 1016 cm-3. Concentrations of the detected elements were monitored as a function of depth of the potatoes. Our study reveals a decreasing tendency in concentration of iron from top to the centre of potato's flesh, whereas, the concentrations of other elements vary randomly.

Plasma, salivary and urinary cortisol levels following physiological and stress doses of hydrocortisone in normal volunteers.

PubMed

Jung, Caroline; Greco, Santo; Nguyen, Hanh H T; Ho, Jui T; Lewis, John G; Torpy, David J; Inder, Warrick J

2014-11-26

Glucocorticoid replacement is essential in patients with primary and secondary adrenal insufficiency, but many patients remain on higher than recommended dose regimens. There is no uniformly accepted method to monitor the dose in individual patients. We have compared cortisol concentrations in plasma, saliva and urine achieved following "physiological" and "stress" doses of hydrocortisone as potential methods for monitoring glucocorticoid replacement. Cortisol profiles were measured in plasma, saliva and urine following "physiological" (20 mg oral) or "stress" (50 mg intravenous) doses of hydrocortisone in dexamethasone-suppressed healthy subjects (8 in each group), compared to endogenous cortisol levels (12 subjects). Total plasma cortisol was measured half-hourly, and salivary cortisol and urinary cortisol:creatinine ratio were measured hourly from time 0 (between 0830 and 0900) to 5 h. Endogenous plasma corticosteroid-binding globulin (CBG) levels were measured at time 0 and 5 h, and hourly from time 0 to 5 h following administration of oral or intravenous hydrocortisone. Plasma free cortisol was calculated using Coolens' equation. Plasma, salivary and urine cortisol at 2 h after oral hydrocortisone gave a good indication of peak cortisol concentrations, which were uniformly supraphysiological. Intravenous hydrocortisone administration achieved very high 30 minute cortisol concentrations. Total plasma cortisol correlated significantly with both saliva and urine cortisol after oral and intravenous hydrocortisone (P <0.0001, correlation coefficient between 0.61 and 0.94). There was no difference in CBG levels across the sampling period. An oral dose of hydrocortisone 20 mg is supraphysiological for routine maintenance, while stress doses above 50 mg 6-hourly would rarely be necessary in managing acute illness. Salivary cortisol and urinary cortisol:creatinine ratio may provide useful alternatives to plasma cortisol measurements to monitor replacement doses in hypoadrenal patients.

The Chemical Potential of Plasma Membrane Cholesterol: Implications for Cell Biology.

PubMed

Ayuyan, Artem G; Cohen, Fredric S

2018-02-27

Cholesterol is abundant in plasma membranes and exhibits a variety of interactions throughout the membrane. Chemical potential accounts for thermodynamic consequences of molecular interactions, and quantifies the effective concentration (i.e., activity) of any substance participating in a process. We have developed, to our knowledge, the first method to measure cholesterol chemical potential in plasma membranes. This was accomplished by complexing methyl-β-cyclodextrin with cholesterol in an aqueous solution and equilibrating it with an organic solvent containing dissolved cholesterol. The chemical potential of cholesterol was thereby equalized in the two phases. Because cholesterol is dilute in the organic phase, here activity and concentration were equivalent. This equivalence allowed the amount of cholesterol bound to methyl-β-cyclodextrin to be converted to cholesterol chemical potential. Our method was used to determine the chemical potential of cholesterol in erythrocytes and in plasma membranes of nucleated cells in culture. For erythrocytes, the chemical potential did not vary when the concentration was below a critical value. Above this value, the chemical potential progressively increased with concentration. We used standard cancer lines to characterize cholesterol chemical potential in plasma membranes of nucleated cells. This chemical potential was significantly greater for highly metastatic breast cancer cells than for nonmetastatic breast cancer cells. Chemical potential depended on density of the cancer cells. A method to alter and fix the cholesterol chemical potential to any value (i.e., a cholesterol chemical potential clamp) was also developed. Cholesterol content did not change when cells were clamped for 24-48 h. It was found that the level of activation of the transcription factor STAT3 increased with increasing cholesterol chemical potential. The cholesterol chemical potential may regulate signaling pathways. Copyright © 2018. Published by Elsevier Inc.

Quantification of acetylcholine, choline, betaine, and dimethylglycine in human plasma and urine using stable-isotope dilution ultra performance liquid chromatography-tandem mass spectrometry.

PubMed

Kirsch, Susanne H; Herrmann, Wolfgang; Rabagny, Yannick; Obeid, Rima

2010-12-15

Disorders in choline metabolism are related to disease conditions. We developed a stable-isotope dilution ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification of acetylcholine (ACh), betaine, choline, and dimethylglycine (DMG). We used this method to measure concentrations of the analytes in plasma and urine in addition to other biological fluids after a protein precipitation by acetonitrile. The detection limits were between 0.35 nmol/L (for ACh in urine) and 0.34 μmol/L (for betaine in urine). ACh concentrations were not detectable in plasma. Intraassay and interassay coefficient of variation (CVs) were all <10.0% in biological fluids, except for DMG in cerebrospinal fluid (CV=12.44%). Mean recoveries in urine pool samples were between 99.2% and 103.9%. The urinary excretion of betaine, choline, and DMG was low, with approximately 50.0% higher excretion of choline in females compared to males. Median urinary excretion of ACh were 3.44 and 3.92 μmol/mol creatinine in males and females, respectively (p=0.689). Plasma betaine concentrations correlated significantly with urinary excretions of betaine (r=0.495, p=0.027) and choline (r=0.502, p=0.024) in females. Plasma choline concentrations correlated significantly with urinary excretion of ACh in males (r=0.419, p=0.041) and females (r=0.621, p=0.003). The new method for the simultaneous determination of ACh, betaine, choline, and DMG is sensitive, precise, and fast enough to be used in clinical investigations related to the methylation pathway. Copyright © 2010 Elsevier B.V. All rights reserved.

Measurement of titanium in hip-replacement patients by inductively coupled plasma optical emission spectroscopy.

PubMed

Harrington, Chris F; McKibbin, Craig; Rahanu, Monika; Langton, David; Taylor, Andrew

2017-05-01

Background Patients with metal-on-metal hip replacements require testing for cobalt and chromium. There may also be a need to test for titanium, which is used in the construction of the femoral stem in total hip replacements. It is not possible to use quadrupole inductively coupled plasma mass spectrometry due to interferences. Methods Titanium was measured using inductively coupled plasma optical emission spectroscopy using the emission line at 336.1 nm and Y (internal standard) at 371.0 nm. Internal quality control materials were prepared for blood and serum and concentrations assigned using a sector field-inductively coupled plasma mass spectrometer. A candidate whole blood certified reference material was also evaluated. Results The method had detection and quantitation limits of 0.6 and 1.9 µg/L, respectively. The respective bias (%) and measurement uncertainty ( U) (k = 2) were 3.3% and 2.0 µg/L (serum) and - 1.0% and 1.4 µg/L (whole blood). The respective repeatability and intermediate precision (%) were 5.1% and 10.9% (serum) and 2.4% and 8.6% (whole blood). The concentration of titanium was determined in patients' samples, serum (median = 2.4 µg/L, n = 897) and whole blood (median = 2.4 µg/L, n = 189). Serum is recommended for monitoring titanium in patients, since the concentration is higher than in whole blood and the matrix less problematic. In hip fluid samples, the concentrations were much higher (mean 58.5 µg/L, median 5.1 µg/L, n = 83). Conclusions A method based on inductively coupled plasma optical emission spectroscopy was developed and validated for measuring titanium in clinical samples.

Recurrent fever of unknown etiology: failure to demonstrate association between fever and plasma unconjugated etiocholanolone

PubMed Central

George, Jack M.; Wolff, Sheldon M.; Diller, Esther; Bartter, Frederic C.

1969-01-01

A sensitive method for determination of plasma unconjugated etiocholanolone by double-isotope-derivative dilution has been described. The mean values for normal subjects was 0.038±0.003 (SEM) μg/100 ml. 40 patients, 20 with familial Mediterranean fever and 20 with other diseases characterized by recurrent fever were studied. The over-all mean concentration of plasma unconjugated etiocholanolone for the patients (febrile or afebrile) was 0.101 ±0.012 μg/100 ml, significantly above that of normals. Mean plasma values for the patients while they were febrile did not differ from the mean values when they were afebrile. It is suggested that the concentration of plasma unconjugated etiocholanolone is not related to fever in these patients. PMID:4886315

Pre-analytical effects of blood sampling and handling in quantitative immunoassays for rheumatoid arthritis.

PubMed

Zhao, Xiaoyan; Qureshi, Ferhan; Eastman, P Scott; Manning, William C; Alexander, Claire; Robinson, William H; Hesterberg, Lyndal K

2012-04-30

Variability in pre-analytical blood sampling and handling can significantly impact results obtained in quantitative immunoassays. Understanding the impact of these variables is critical for accurate quantification and validation of biomarker measurements. Particularly, in the design and execution of large clinical trials, even small differences in sample processing and handling can have dramatic effects in analytical reliability, results interpretation, trial management and outcome. The effects of two common blood sampling methods (serum vs. plasma) and two widely-used serum handling methods (on the clot with ambient temperature shipping, "traditional", vs. centrifuged with cold chain shipping, "protocol") on protein and autoantibody concentrations were examined. Matched serum and plasma samples were collected from 32 rheumatoid arthritis (RA) patients representing a wide range of disease activity status. Additionally, a set of matched serum samples with two sample handling methods was collected. One tube was processed per manufacturer's instructions and shipped overnight on cold packs (protocol). The matched tube, without prior centrifugation, was simultaneously shipped overnight at ambient temperatures (traditional). Upon delivery, the traditional tube was centrifuged. All samples were subsequently aliquoted and frozen prior to analysis of protein and autoantibody biomarkers. Median correlation between paired serum and plasma across all autoantibody assays was 0.99 (0.98-1.00) with a median % difference of -3.3 (-7.5 to 6.0). In contrast, observed protein biomarker concentrations were significantly affected by sample types, with median correlation of 0.99 (0.33-1.00) and a median % difference of -10 (-55 to 23). When the two serum collection/handling methods were compared, the median correlation between paired samples for autoantibodies was 0.99 (0.91-1.00) with a median difference of 4%. In contrast, significant increases were observed in protein biomarker concentrations among certain biomarkers in samples processed with the 'traditional' method. Autoantibody quantification appears robust to both sample type (plasma vs. serum) and pre-analytical sample collection/handling methods (protocol vs. traditional). In contrast, for non-antibody protein biomarker concentrations, sample type had a significant impact; plasma samples generally exhibit decreased protein biomarker concentrations relative to serum. Similarly, sample handling significantly impacted the variability of protein biomarker concentrations. When biomarker concentrations are combined algorithmically into a single test score such as a multi-biomarker disease activity test for rheumatoid arthritis (MBDA), changes in protein biomarker concentrations may result in a bias of the score. These results illustrate the importance of characterizing pre-analytical methodology, sample type, sample processing and handling procedures for clinical testing in order to ensure test accuracy. Copyright © 2012 Elsevier B.V. All rights reserved.

Development and validation of an UPLC-MS/MS method for the quantification of irinotecan, SN-38 and SN-38 glucuronide in plasma, urine, feces, liver and kidney: Application to a pharmacokinetic study of irinotecan in rats.

PubMed

Basu, Sumit; Zeng, Min; Yin, Taijun; Gao, Song; Hu, Ming

2016-03-15

The objective of this research is to develop and validate a sensitive and reproducible UPLC-MS/MS method to quantify irinotecan, its active metabolite SN-38 and SN-38 glucuronide (phase II metabolite of SN-38) simultaneously in different bio-matrices (plasma, urine, feces), tissues (liver and kidney) and to use the method to investigate its pharmacokinetic behavior in rats. Irinotecan, SN-38 and SN-38 glucuronide has been resolved and separated by C18 column using acetonitrile and 0.1% formic acid in water used as the mobile phases. Triple quadruple mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode were employed to perform mass analysis. The results showed that the linear response range of irinotecan and SN-38 in plasma, feces, liver and kidney is 4.88-10000 nM, 39-5000 nM, 48.8-6250 nM and 48.8-6250 nM, respectively (R(2)>0.99). In case of SN-38 glucuronide, the standard curves were linear in the concentration range of 6.25-2000 nM, 4.88-1250 nM, 9.8-1250 nM and 9.8-1250 nM in plasma, feces, liver and kidney homogenates, respectively. The lower limit of detection (LLOD) of irinotecan, SN-38 and SN-38 glucuronide was determined to be less than 25 nM in all bio-matrices as well as tissue homogenates. Recoveries of irinotecan, SN-38 and SN-38 glucuronide at three different concentrations (low, medium and high) were not less than 85% at three different concentrations in plasma and feces. The percentage matrix factors in different bio-matrices and tissues were within 20%. The UPLC-MS/MS method was validated with intra-day and inter-day precision of less than 15% in plasma, feces, liver and kidney. Owing to the high sensitivity of this method, only 20 μl of plasma, urine and homogenates of liver, kidney and feces is needed. The validated method has been successfully employed for pharmacokinetic evaluation of irinotecan in male wistar rats to quantify irinotecan, SN-38 and SN-38 glucuronide in plasma, feces, and urine samples. Published by Elsevier B.V.

Development and validation of an UPLC-MS/MS method for the quantification of irinotecan, SN 38 and SN-38 glucuronide in plasma, urine, feces, liver and kidney: Application to a pharmacokinetic study of irinotecan in rats

PubMed Central

Basu, Sumit; Zeng, Min; Yin, Taijun; Gao, Song; Hu, Ming

2016-01-01

The objective of this research is to develop and validate a sensitive and reproducible UPLC-MS/MS method to quantify irinotecan, its active metabolite SN-38 and SN-38 glucuronide (phase II metabolite of SN-38) simultaneously in different bio-matrices (plasma, urine, feces), tissues (liver and kidney) and to use the method to investigate its pharmacokinetic behavior in rats. Irinotecan, SN-38 and SN-38 glucuronide has been resolved and separated by C18 column using acetonitrile and 0.1% formic acid in water used as the mobile phases. Triple quadruple mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode were employed to perform mass analysis. The results showed that the linear response range of irinotecan and SN-38 in plasma, feces, liver and kidney is 4.88 –10000 nM, 39 – 5000 nM, 48.8 –6250 nM and 48.8 – 6250 nM, respectively (R2 > 0.99). In case of SN-38 glucuronide, the standard curves were linear in the concentration range of 6.25 – 2000 nM, 4.88 – 1250 nM, 9.8 – 1250 nM and 9.8 – 1250 nM in plasma, feces, liver and kidney homogenates, respectively. The lower limit of detection (LLOD) of irinotecan, SN-38 and SN-38 glucuronide was determined to be less than 25 nM in all bio-matrices as well as tissue homogenates. Recoveries of irinotecan, SN-38 and SN-38 glucuronide at three different concentrations (low, medium and high) were not less than 85% at three different concentrations in plasma and feces. The percentage matrix factors in different bio-matrices and tissues were within 20%. The UPLC-MS/MS method was validated with intra-day and inter-day precision of less than 15% in plasma, feces, liver and kidney. Owing to the high sensitivity of this method, only 20 µl of plasma, urine and homogenates of liver, kidney and feces is needed. The validated method has been successfully employed for pharmacokinetic evaluation of irinotecan in male wistar rats to quantify irinotecan, SN-38 and SN-38 glucuronide in plasma, feces, and urine samples. PMID:26894853

Plasma D-dimer as a predictor of the progression of abdominal aortic aneurysm.

PubMed

Vele, E; Kurtcehajic, A; Zerem, E; Maskovic, J; Alibegovic, E; Hujdurovic, A

2016-11-01

Essentials D-dimer could provide important information about abdominal aortic aneurysm (AAA) progression. The greatest diameter of the infrarenal aorta and the value of plasma D-dimer were determined. AAA progression is correlated with increasing plasma D-dimer levels. The increasing value of plasma D-dimer could be a predictor of aneurysm progression. Background The natural course of abdominal aortic aneurysm (AAA) is mostly asymptomatic and unpredictable. D-dimer could provide potentially important information about subsequent AAA progression. Objectives The aims of this study were to establish the relationship between the progression of an abdominal aortic aneurysm (AAA) and plasma D-dimer concentration over a 12-month period and determine the value of plasma D-dimer in patients with sub-aneurysmal aortic dilatation. Patients/Methods This was a prospective observational study that involved 33 patients with an AAA, 30 patients with sub-aneurysmal aortic dilatation and 30 control subjects. The greatest diameter of the infrarenal aorta, which was assessed by ultrasound, and the value of plasma D-dimer were determined for all subjects at baseline assessment, as well as after 12 months for those with an AAA. Results A positive correlation was found between the diameter of an AAA and plasma D-dimer concentration at the baseline and the control measurement stages. There was a strong positive correlation between AAA progression and increasing plasma D-dimer concentration over a 12-month period. Among patients with sub-aneurysmal aortic dilatation (n = 30), the value of plasma D-dimer was higher compared with matched controls (n = 30). Conclusions There is a strongly positive correlation between AAA progression and increasing plasma D-dimer concentration. The value of plasma D-dimer is higher in patients with sub-aneurysmal aortic dilatation than in control subjects. © 2016 International Society on Thrombosis and Haemostasis.

Comparison of Analytical Methods for the Determination of Uranium in Seawater Using Inductively Coupled Plasma Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Jordana R.; Gill, Gary A.; Kuo, Li-Jung

2016-04-20

Trace element determinations in seawater by inductively coupled plasma mass spectrometry are analytically challenging due to the typically very low concentrations of the trace elements and the potential interference of the salt matrix. In this study, we did a comparison for uranium analysis using inductively coupled plasma mass spectrometry (ICP-MS) of Sequim Bay seawater samples and three seawater certified reference materials (SLEW-3, CASS-5 and NASS-6) using seven different analytical approaches. The methods evaluated include: direct analysis, Fe/Pd reductive precipitation, standard addition calibration, online automated dilution using an external calibration with and without matrix matching, and online automated pre-concentration. The methodmore » which produced the most accurate results was the method of standard addition calibration, recovering uranium from a Sequim Bay seawater sample at 101 ± 1.2%. The on-line preconcentration method and the automated dilution with matrix-matched calibration method also performed well. The two least effective methods were the direct analysis and the Fe/Pd reductive precipitation using sodium borohydride« less

The association of plasma gamma-aminobutyric acid concentration with postoperative delirium in critically ill patients.

PubMed

Yoshitaka, Shiho; Egi, Moritoki; Kanazawa, Tomoyuki; Toda, Yuichiro; Morita, Kiyoshi

2014-12-01

Delirium is a common complication in postoperative, critically ill patients. The mechanism of postoperative delirium is not well understood but many studies have shown significant associations between benzodiazepine use, alcohol withdrawal and cirrhosis, and an increased risk of delirium. We aimed to investigate a possible link with alterations of gamma-aminobutyric acid (GABA) activity. A prospective observational investigation of 40 patients > 20 years old who had undergone elective surgery with general anaesthesia and were expected to need postoperative intensive care for more than 48 hours. We assessed postoperative delirium using the confusion assessment method in the intensive care unit at 1 hour after the operation and on postoperative Day (POD) 1 and POD 2. We collected blood samples for measurement of plasma GABA concentrations before the operation and on POD 1 and 2. Postoperative delirium and perioperative plasma GABA concentrations in patients with and without delirium. Postoperative delirium occurred in 13 of the patients. Patients with delirium had significantly higher Acute Physiology and Chronic Health Evaluation II scores than patients without delirium. The mean plasma GABA concentration on POD 2 was significantly lower in patients with delirium than in those without delirium. After adjustment of relevant variables, plasma GABA concentration on POD 2 was independently associated with postoperative delirium. Plasma GABA level on POD 2 has a significant independent association with postoperative delirium.

Nano-LC-MS/MS for Quantification of Lyso-Gb3 and Its Analogues Reveals a Useful Biomarker for Fabry Disease

PubMed Central

Sueoka, Hideaki; Ichihara, Junji; Tsukimura, Takahiro; Togawa, Tadayasu; Sakuraba, Hitoshi

2015-01-01

Biomarkers useful for diagnosis and evaluation of treatment for patients with Fabry disease are urgently needed. Recently, plasma globotriaosylsphingosine (lyso-Gb3) and lyso-Gb3-related analogues have attracted attention as promising biomarkers of Fabry disease. However, the plasma concentrations of lyso-Gb3 and its analogues are extremely low or below the detection limits in some Fabry patients as well as in healthy subjects. In this paper, we introduce the novel application of a nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) system to the measurement of lyso-Gb3 and its analogues in plasma. Nano-LC-MS/MS requires smaller amounts of samples and is more sensitive than conventional techniques. Using this method, we measured the plasma concentrations of lyso-Gb3 and its analogues in 40 healthy subjects, 5 functional variants (males with E66Q), and various Fabry patients (9 classic Fabry males/9 mutations; 7 later-onset Fabry males/5 mutations; and 10 Fabry females/9 mutations). The results revealed that the mean lyso-Gb3 and lyso-Gb3(-2) concentrations in all the Fabry patient subgroups were statistically higher, especially in the classic Fabry males, than those in the functional variants and healthy subjects. The plasma concentrations of lyso-Gb3 and its analogues in healthy subjects, functional variants, and some Fabry patients with specific mutations (R112H and M296I) that cannot be established by conventional techniques were successfully determined by means of nano-LC-MS/MS. The lyso-Gb3 and lyso-Gb3(-2) concentrations in male patients with these mutations were lower than those in most Fabry patients having other mutations, but higher than those in the functional variants and healthy subjects. This new method is expected to be useful for sensitive determination of the plasma concentrations of lyso-Gb3 and its analogues. This study also revealed that not only lyso-Gb3 but also lyso-Gb3(-2) in plasma is a useful biomarker for the diagnosis of Fabry disease. PMID:25965380

Pre-formulation characterization and pharmacokinetic evaluation of resveratrol

NASA Astrophysics Data System (ADS)

Robinson-Barnes, Keila Delores

Resveratrol, a natural compound found in grapes has potential chemotherapy effects but very low oral bioavailability in humans. The objectives of this study are to quantitatively characterized and understand the physiochemical properties and the pharmacokinetic evaluation of resveratrol. Solubility of resveratrol was measured in 10 common solvents at 25°C using HPLC. The solution state pH stability of resveratrol was assessed in various USP buffers ranging from pH 2-10 for 24 hours at 37 °C. Human plasma protein binding was determined using ultracentrifugation technique. Stability of resveratrol in human and rat plasma was also assessed at 37°C. Aliquots of blank plasma were spiked with a standard drug concentration to yield final plasma concentration of 50 mug/mL. Samples were analyzed for resveratrol concentration up to 96 hours. A group (n=8) of jugular vein-cannulated adult male Sprague-Dawley rats were evaluated and received intravenous dose of 20 mg/kg resveratrol. Serial blood samples were collected up to 8 hours after the dose. Plasma concentrations of resveratrol were measured by an established LC-MS/MS method. Pharmacokinetic parameters were assessed using noncompartmental methods. Resveratrol is more soluble in alcohol and PEG-400, and stable in acidic pH. It binds highly to plasma proteins, and degrades slower in human then rat plasma. Resveratrol exhibits bioexponential disposition after intravenous administration and has a short elimination half-life. Resveratrol displays bioexponential disposition following intravenous administration. The estimated mean maximum concentration was 1045.5 ng/mL and rapidly dropped below 100 ng/mL within 30 minutes. The area under the concentration time curve (AUC) for resveratrol was 13888.7 min*ng/mL The mean terminal elimination half-life was 50.9 minutes. The mean total body clearance (Cl) and volume of distribution of trans-resveratrol were 1711.9mL/min/kg and 91087.8 mL/kg, respectively. Pre-formulation optimization and pharmacokinetic assessment after intravenous administration was successfully described. The results from this study will aid in the development of a new novel drug delivery system for resveratrol that demonstrates clinical therapeutic effects.

N-acetyltransferase gene polymorphisms & plasma isoniazid concentrations in patients with tuberculosis

PubMed Central

Hemanth Kumar, A. K.; Ramesh, K.; Kannan, T.; Sudha, V.; Haribabu, Hemalatha; Lavanya, J.; Swaminathan, Soumya; Ramachandran, Geetha

2017-01-01

Background & objectives: Variations in the N-acetyltransferase (NAT2) gene among different populations could affect the metabolism and disposition of isoniazid (INH). This study was performed to genotype NAT2 gene polymorphisms in tuberculosis (TB) patients from Chennai, India, and compare plasma INH concentrations among the different genotypes. Methods: Adult patients with TB treated in the Revised National TB Control Programme (RNTCP) in Chennai, Tamil Nadu, were genotyped for NAT2 gene polymorphism, and two-hour post-dosing INH concentrations were compared between the different genotypes. Plasma INH was determined by high-performance liquid chromatography. Genotyping of the NAT2 gene polymorphism was performed by real-time polymerase chain reaction method. Results: Among the 326 patients genotyped, there were 189 (58%), 114 (35%) and 23 (7%) slow, intermediate and fast acetylators, respectively. The median two-hour INH concentrations in slow, intermediate and fast acetylators were 10.2, 8.1 and 4.1 μg/ml, respectively. The differences in INH concentrations among the three genotypes were significant (P<0.001). Interpretation & conclusions: Genotyping of TB patients from south India for NAT2 gene polymorphism revealed that 58 per cent of the study population comprised slow acetylators. Two-hour INH concentrations differed significantly among the three genotypes. PMID:28574024

Endocan, a putative endothelial cell marker, is elevated in preeclampsia, decreased in acute pyelonephritis, and unchanged in other obstetrical syndromes

PubMed Central

Adekola, Henry; Romero, Roberto; Chaemsaithong, Piya; Korzeniewski, Steven J.; Dong, Zhong; Yeo, Lami; Hassan, Sonia S.; Chaiworapongsa, Tinnakorn

2015-01-01

Abstract Objective: Endocan, a dermatan sulphate proteoglycan produced by endothelial cells, is considered a biomarker for endothelial cell activation/dysfunction. Preeclampsia is characterized by systemic vascular inflammation, and endothelial cell activation/dysfunction. Therefore, the objectives of this study were to determine whether: (1) plasma endocan concentrations in preeclampsia differ from those in uncomplicated pregnancies; (2) changes in plasma endocan concentration relate to the severity of preeclampsia, and whether these changes are specific or observed in other obstetrical syndromes such as small-for-gestational age (SGA), fetal death (FD), preterm labor (PTL) or preterm prelabor rupture of membranes (PROM); (3) a correlation exists between plasma concentration of endocan and angiogenic (placental growth factor or PlGF)/anti-angiogenic factors (soluble vascular endothelial growth factor receptor or sVEGFR-1, and soluble endoglin or sEng) among pregnancies complicated by preeclampsia; and (4) plasma endocan concentrations in patients with preeclampsia and acute pyelonephritis (both conditions in which there is endothelial cell activation) differ. Method: This cross-sectional study included the following groups: (1) uncomplicated pregnancy (n = 130); (2) preeclampsia (n = 102); (3) pregnant women without preeclampsia who delivered an SGA neonate (n = 51); (4) FD (n = 49); (5) acute pyelonephritis (AP; n = 35); (6) spontaneous PTL (n = 75); and (7) preterm PROM (n = 64). Plasma endocan concentrations were determined in all groups, and PIGF, sEng and VEGFR-1 plasma concentrations were measured by ELISA in the preeclampsia group. Results: (1) Women with preeclampsia had a significantly higher median plasma endocan concentration than those with uncomplicated pregnancies (p = 0.004); (2) among women with preeclampsia, the median plasma endocan concentration did not differ significantly according to disease severity (p = 0.1), abnormal uterine artery Doppler velocimetry (p = 0.7) or whether diagnosis was made before or after 34 weeks gestational age (p = 0.3); (3) plasma endocan concentration in women with preeclampsia correlated positively with plasma anti-angiogenic factor concentrations [sVEGFR-1: Spearman rho 0.34, p = 0.001 and sEng: Spearman rho 0.30, p = 0.003]; (4) pregnancies complicated by acute pyelonephritis with bacteremia had a lower median plasma endocan concentration than pregnancies complicated by acute pyelonephritis without bacteremia (p = 0.004), as well as uncomplicated pregnancies (p = 0.001); and (5) there was no significant difference in the median plasma endocan concentration between uncomplicated pregnancies and those complicated by FD, delivery of an SGA neonate, PTL or preterm PROM (other members of the “great obstetrical syndromes”; each p > 0.05). Conclusion: Median maternal plasma endocan concentrations were higher preeclampsia and lower in acute pyelonephritis with bacteremia than in uncomplicated pregnancy. No significant difference was observed in the median plasma endocan concentration between other great obstetrical syndromes and uncomplicated pregnancies. The difference in the direction of change of endocan in preeclampsia and acute pyelonephritis with bacteremia may be consistent with the view that both disease entities differ in pathogenic mechanisms, despite their associations with systemic vascular inflammation and endothelial cell activation/dysfunction. PMID:25211383

Recommendations for Improving Identification and Quantification in Non-Targeted, GC-MS-Based Metabolomic Profiling of Human Plasma

PubMed Central

Wang, Hanghang; Muehlbauer, Michael J.; O’Neal, Sara K.; Newgard, Christopher B.; Hauser, Elizabeth R.; Shah, Svati H.

2017-01-01

The field of metabolomics as applied to human disease and health is rapidly expanding. In recent efforts of metabolomics research, greater emphasis has been placed on quality control and method validation. In this study, we report an experience with quality control and a practical application of method validation. Specifically, we sought to identify and modify steps in gas chromatography-mass spectrometry (GC-MS)-based, non-targeted metabolomic profiling of human plasma that could influence metabolite identification and quantification. Our experimental design included two studies: (1) a limiting-dilution study, which investigated the effects of dilution on analyte identification and quantification; and (2) a concentration-specific study, which compared the optimal plasma extract volume established in the first study with the volume used in the current institutional protocol. We confirmed that contaminants, concentration, repeatability and intermediate precision are major factors influencing metabolite identification and quantification. In addition, we established methods for improved metabolite identification and quantification, which were summarized to provide recommendations for experimental design of GC-MS-based non-targeted profiling of human plasma. PMID:28841195

Pharmacokinetics of orally administered DL-α-lipoic acid in dogs.

PubMed

Zicker, Steven C; Avila, Albert; Joshi, Dinesh K; Gross, Kathy L

2010-11-01

To determine the pharmacokinetics of DL-α-lipoic acid in dogs when administered at 3 dosages via 3 methods of delivery. 27 clinically normal Beagles. In a 3 × 3 factorial Latin square design, 3 dosages (2.5, 12.5, and 25 mg/kg) of DL-α-lipoic acid were administered orally in a capsule form and provided without a meal, in a capsule form and provided with a meal, and as an ingredient included in an extruded dog food. Food was withheld for 12 hours prior to DL-α-lipoic acid administration. Blood samples were collected before (0 minutes) and at 15, 30, 45, 60, and 120 minutes after administration. Plasma concentrations of DL-α-lipoic acid were determined via high-performance liquid chromatography. A generalized linear models procedure was used to evaluate the effects of method of delivery and dosage. Noncompartmental analysis was used to determine pharmacokinetic parameters of DL-α-lipoic acid. Nonparametric tests were used to detect significant differences between pharmacokinetic parameters among treatment groups. A significant effect of dosage was observed regardless of delivery method. Method of delivery also significantly affected plasma concentrations of DL-α-lipoic acid, with extruded foods resulting in lowest concentration for each dosage administered. Maximum plasma concentration was significantly affected by method of delivery at each dosage administered. Other significant changes in pharmacokinetic parameters were variable and dependent on dosage and method of delivery. Values for pharmacokinetic parameters of orally administered DL-α-lipoic acid may differ significantly when there are changes in dosage, method of administration, and fed status.

Increased PAI-1 plasma levels and risk of death from dengue: no association with the 4G/5G promoter polymorphism

PubMed Central

Mairuhu, ATA; Setiati, TE; Koraka, P; Hack, CE; Leyte, A; Faradz, SMH; ten Cate, H; Brandjes, DPM; Osterhaus, ADME; Reitsma, PH; van Gorp, ECM

2005-01-01

Background Dengue virus infected patients have high plasminogen activator inhibitor type I (PAI-1) plasma concentrations. Whether the insertion/deletion (4G/5G) polymorphism in the promotor region of the PAI-1 gene is associated with increased PAI-1 plasma concentrations and with death from dengue is unknown. We, therefore, investigated the relationship between the 4G/5G polymorphism and PAI-1 plasma concentrations in dengue patients and risk of death from dengue. Methods A total of 194 patients admitted to the Dr. Kariadi Hospital in Semarang, Indonesia, with clinical suspected severe dengue virus infection were enrolled. Blood samples were obtained on day of admission, days 1, 2 and 7 after admission and at a 1-month follow-up visit. Plasma concentrations of PAI-1 were measured using a sandwich ELISA kit. The PAI-1 4G/5G polymorphism was typed by allele-specific PCR analysis. Results Concentrations of PAI-1 on admission and peak values of PAI-1 during admission were higher than the values measured in healthy controls. Survival was significantly worse in patients with PAI-1 concentrations in the highest tertile (at admission: OR 4.7 [95% CI 0.9–23.8], peak value during admission: OR 6.3 [95%CI 1.3–30.8]). No association was found between the PAI-1 4G/5G polymorphism, and PAI-1 plasma concentrations, dengue disease severity and mortality from dengue. Conclusion These data suggest that the 4G/5G polymorphism has no significant influence on PAI-1 concentrations in dengue virus infected patients and is not associated with the risk of death from dengue. Other factors contributing to the variability of PAI-1 plasma concentrations in patients with dengue need to be explored. PMID:16274483

Pharmaceuticals in water, fish and osprey nestlings in Delaware River and Bay

USGS Publications Warehouse

Bean, Thomas G.; Rattner, Barnett A.; Lazarus, Rebecca S.; Day, Daniel D.; Burket, S. Rebekah; Brooks, Bryan W.; Haddad, Samuel P.; Bowerman, William W.

2018-01-01

Exposure of wildlife to Active Pharmaceutical Ingredients (APIs) is likely to occur but studies of risk are limited. One exposure pathway that has received attention is trophic transfer of APIs in a water-fish-osprey food chain. Samples of water, fish plasma and osprey plasma were collected from Delaware River and Bay, and analyzed for 21 APIs. Only 2 of 21 analytes exceeded method detection limits in osprey plasma (acetaminophen and diclofenac) with plasma levels typically 2–3 orders of magnitude below human therapeutic concentrations (HTC). We built upon a screening level model used to predict osprey exposure to APIs in Chesapeake Bay and evaluated whether exposure levels could have been predicted in Delaware Bay had we just measured concentrations in water or fish. Use of surface water and BCFs did not predict API concentrations in fish well, likely due to fish movement patterns, and partitioning and bioaccumulation uncertainties associated with these ionizable chemicals. Input of highest measured API concentration in fish plasma combined with pharmacokinetic data accurately predicted that diclofenac and acetaminophen would be the APIs most likely detected in osprey plasma. For the majority of APIs modeled, levels were not predicted to exceed 1 ng/mL or method detection limits in osprey plasma. Based on the target analytes examined, there is little evidence that APIs represent a significant risk to ospreys nesting in Delaware Bay. If an API is present in fish orders of magnitude below HTC, sampling of fish-eating birds is unlikely to be necessary. However, several human pharmaceuticals accumulated in fish plasma within a recommended safety factor for HTC. It is now important to expand the scope of diet-based API exposure modeling to include alternative exposure pathways (e.g., uptake from landfills, dumps and wastewater treatment plants) and geographic locations (developing countries) where API contamination of the environment may represent greater risk.

LC-MS/MS method for the determination of clodronate in human plasma.

PubMed

Hasan, Mahmoud; Schumacher, Gitta; Seekamp, Anne; Taedken, Tobias; Siegmund, Werner; Oswald, Stefan

2014-11-01

Clodronate belongs to the class of bisphosphonates which are used for the treatment of bone disorders. Due to its high polarity it has a low and highly variable oral bioavailability which results in low plasma concentrations and requires sensitive bioanalytical methods to characterize its pharmacokinetics in human. Here, we describe for the first time the development and validation of a LC-MS/MS assay for the quantification of clodronate in human plasma. The bisphosphonate was isolated from the biological matrix by protein precipitation using perchloric acid (10%), and derivatized with trimethylorthoacetate prior sample clean-up with liquid-liquid extraction using methyl tert-butyl ether. The chromatography was performed using an isocratic elution with ammonium acetate 5mM (85% v/v, pH 3.8) and acetonitrile (15% v/v) as mobile phase with a flow rate of 300μl/min on a reversed-phase column (Supelco Ascentis(®), C18) temporized at 50°C. The mass spectrometric detection was done using the API4000 triple quadruple mass spectrometer monitoring the mass/charge transitions 301.0/145 for clodronate and 305.2/137.1 for the internal standard etidronate. The analytical range was set to 5-800ng/ml, allowing an evaluation of the plasma concentration-time profiles of clodronate for approximately 7-8 half-life (∼24h). The method was validated according to current FDA/EMA guidelines on bioanalytical method validation with respect to specificity, linearity, intra- and inter-day accuracy and precision, matrix effect, recovery as well as stability. The precision of the assay was 0.6-6.9% and 0.6-8.1% for the intra-day and inter-day variability, respectively. The intra-day and inter-day accuracy (error) was 0.6-8.8% and 2.2-4.5%. The recovery of the analyte was low (2-3%) but reproducible over the entire validation range and sufficient to monitor the target concentrations in human plasma. The drug was shown to be stable in plasma at room temperature for at least 3h (96.0±6%) and for at least 24h when stored in the cooled autosampler at 4°C (102.4±4.5%). Clodronate can also undergo up to three freeze-thaw cycles without impaired stability. Thus, the method was shown to possess sufficient specificity, sensitivity, accuracy, precision and stability to measure plasma concentrations of clodronate. Finally, the developed method was successfully applied to study the clodronate serum levels in a pharmacokinetic study in healthy volunteers. Copyright © 2014 Elsevier B.V. All rights reserved.

Local infiltration analgesia in knee and hip arthroplasty efficacy and safety.

PubMed

Affas, Fatin

2016-10-01

This is a secondary publication of a PhD thesis. Local infiltration analgesia (LIA) is a new multimodal wound infiltration method for treating postoperative pain after knee and hip arthroplasty. This method is based on systematic infiltration of a mixture of ropivacaine, a long acting local anaesthetic, ketorolac, a cyclooxygenase inhibitor (NSAID), and adrenalin around all structures subject to surgical trauma in knee and hip arthroplasty. Paper I: to assess whether pain relief after LIA in total knee arthroplasty (TKA) is as effective as femoral block. Paper II: to assess whether the plasma concentration of ropivacaine and ketorolac after LIA in TKA reaches levels linked to toxicity. Paper III: to assess whether the plasma concentration of unbound ropivacaine after LIA in THA reaches levels linked to toxicity and if it is higher in THA as compared to TKA. Paper IV: to assess whether the plasma concentration of ketorolac after LIA in THA reaches levels linked to toxicity, and whether administration of ketorolac in LIA is safer as compared to the intramuscular route. Two patient cohorts of 40 patients scheduled for elective total knee arthroplasty (TKA) and 15 patients scheduled for total hip arthroplasty (THA) contributed to this work. In a randomized trial the efficacy of LIA in TKA with regard to pain at rest and upon movement was compared to femoral block. Both methods result in a high quality pain relief and similar morphine consumption during the 24h monitoring period. In the same patient cohort the maximal total plasma concentration of ropivacaine was below the established toxic threshold for most patients. All patients in the THA cohort were subjected to the routine LIA protocol. In these patients both the total and unbound plasma concentration of ropivacaine was determined. The concentration was below the established toxic threshold. As ropivacaine binds to α-1 acid glycoprotein (AAG) we assessed the possibility that increased AAG may decrease the unbound concentration of ropivacaine. A 40% increase in AAG was detected during the first 24h after surgery, however the fraction of unbound ropivacaine remained the same. There was a trend towards increased C max of ropivacaine with increasing age and decreasing creatinine clearance but the statistical power was too low to draw any conclusion. Administration of 30mg ketorolac according to the LIA protocol both in TKA and THA resulted in a similar C max as previously reported after 10mg intramuscular ketorolac. Neither age, nor body weight or BMI, nor creatinine clearance, correlates to maximal ketorolac plasma concentration or total exposure to ketorolac (AUC). LIA provides good postoperative analgesia which is similar to femoral block after total knee arthroplasty. The plasma concentration of ropivacaine seems to be below toxic levels in most TKA patients. The unbound plasma concentration of ropivacaine in THA seems to be below the toxic level. The use of ketorolac in LIA may not be safer than other routes of administration, and similar restrictions should be applied in patients at risk of developing side effects. Copyright © 2016. Published by Elsevier B.V.

Assessment of 7.5% NaCl /6% Dextran-70 (HSD) Effects on Serum or Plasma Protein Determinations

DTIC Science & Technology

1990-12-26

determined by modified Lowry, dye-binding, and an automated biuret method, as well as by refractometry , before, and at various times following HSD...protein concentrations determined by the biuret assay or refractometry when dextran serum concentrations exceeded 1.2 g/dl. The in vivo studies... refractometry , before, and at various times following HSD infusion in both euvolemic and hemorrhaged animals. Other studies analyzed plasma protein

Effects of the pulse width on the reactive species production and DNA damage in cancer cells exposed to atmospheric pressure microsecond-pulsed helium plasma jets

NASA Astrophysics Data System (ADS)

Joh, Hea Min; Choi, Ji Ye; Kim, Sun Ja; Kang, Tae Hong; Chung, T. H.

2017-08-01

Plasma-liquid and plasma-cell interactions were investigated using an atmospheric pressure dc microsecond-pulsed helium plasma jet. We investigated the effects of the electrical parameters such as applied voltage and pulse width (determined by the pulse frequency and duty ratio) on the production of reactive species in the gas/liquid phases and on the DNA damage responses in the cancer cells. The densities of reactive species including OH radicals were estimated inside the plasma-treated liquids using a chemical probe method, and the nitrite concentration was detected by Griess assay. Importantly, the more concentration of OH resulted in the more DNA base oxidation and breaks in human lung cancer A549 cells. The data are very suggestive that there is strong correlation between the production of OH in the plasmas/liquids and the DNA damage.

Alcohol consumption reduces HbA1c and glycated albumin concentrations but not 1,5-anhydroglucitol.

PubMed

Inada, Shinya; Koga, Masafumi

2017-11-01

Background The effect of alcohol consumption on glycaemic control indicators is not well known. In this study, we studied the effect of alcohol consumption on the plasma glucose and glycaemic control indicators in non-diabetic men. Methods The study enrolled 300 non-diabetic men who received a complete medical checkup (age: 52.8 ± 6.5 years, body mass index: 24.4 ± 2.8 kg/m 2 ). The subjects were divided into four groups by the amount of alcohol consumed, and the plasma glucose, HbA1c, glycated albumin (GA) and 1,5-anhydroglucitol (1,5-AG) concentrations of the groups were compared. Results As the level of alcohol consumption increased, significantly high concentrations of fasting plasma glucose (FPG) were observed, and the oral glucose tolerance test 2-h plasma glucose concentrations tended to rise. While no significant effect of alcohol consumption on HbA1c, 1,5-AG, and the 1,5-AG/FPG ratio was observed, the HbA1c/FPG ratio, GA and the GA/FPG ratio exhibited significantly low values as the level of alcohol consumption increased. In stepwise multivariate regression analysis, alcohol consumption was a significant negative independent variable for HbA1c and GA, but not for 1,5-AG. Conclusions As the level of alcohol consumption increased, the plasma glucose concentrations rose, but the HbA1c and GA concentrations were lower compared with the plasma glucose concentrations. These findings suggest that alcohol consumption may reduce HbA1c and GA concentrations, but not 1,5-AG.

Deposition of gold nano-particles and nano-layers on polyethylene modified by plasma discharge and chemical treatment

NASA Astrophysics Data System (ADS)

Švorčík, V.; Chaloupka, A.; Záruba, K.; Král, V.; Bláhová, O.; Macková, A.; Hnatowicz, V.

2009-08-01

Polyethylene (PE) was treated in Ar plasma discharge and then grafted from methanol solution of 1,2-ethanedithiol to enhance adhesion of gold nano-particles or sputtered gold layers. The modified PE samples were either immersed into freshly prepared colloid solution of Au nano-particles or covered by sputtered, 50 nm thick gold nano-layer. Properties of the plasma modified, dithiol grafted and gold coated PE were studied using XPS, UV-VIS, AFM, EPR, RBS methods and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain, creation of excessive free radicals and conjugated double bonds. After grafting with 1,2-ethanedithiol the concentration of free radicals declined but the concentration of double bonds remained unchanged. Plasma treatment changes PE surface morphology and increases surface roughness too. Another significant change in the surface morphology and roughness was observed after deposition of Au nano-particles. The presence of Au on the sample surface after the coating with Au nano-particles was proved by XPS and RBS methods. Nanoindentation measurements shown that the grafting of plasma activated PE surface with dithiol increases significantly adhesion of sputtered Au nano-layer.

Particle-induced X-ray emission analysis of elements in plasma from wild and captive sea turtles (Eretmochelys imbricata, Chelonia mydas, and Caretta caretta) in Okinawa, Japan.

PubMed

Suzuki, Kazuyuki; Noda, Jun; Yanagisawa, Makio; Kawazu, Isao; Sera, Kouichiro; Fukui, Daisuke; Asakawa, Mitsuhiko; Yokota, Hiroshi

2012-09-01

The aim of this study was to evaluate the reliability of direct determination of trace and major element concentrations in plasma samples from wild (six hawksbill, nine green, and nine loggerhead) and captive sea turtles (25 howksbill, five green, and three loggerhead) in Okinawa, Japan. The particle induced X-ray emission method allowed detection of 23 trace and major elements (Al, As, Br, Ca, Cl, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Ni, P, Pb, S, Se, Si, Sr, Ti, Y, and Zn). The wild sea turtles were found to have high concentrations of As and Pb in plasma compared with captive, but there were no significant changes in the Al and Hg concentrations. Loggerhead sea turtles were found to have significantly higher accumulation of As and Pb in plasma in comparison to other species. These findings may be useful when adjusting environmental and species-related factors in severely polluted marine ecosystems. Our results indicate that measuring the plasma As and Pb concentrations in wild sea turtles might be of help to assess the level of pollution in marine ecosystems, keeping in mind that loggerhead sea turtles had been shown to have higher levels of As and Pb in plasma.

Prognosis and survival analysis of paraquat poisoned patients based on improved HPLC-UV method.

PubMed

Hong, Guangliang; Hu, Lufeng; Tang, Yahui; Zhang, Tao; Kang, Xiaowen; Zhao, Guangju; Lu, Zhongqiu

2016-01-01

Paraquat (PQ) has caused deaths of numerous people around the world. In order to assess the lethal plasma concentration, the patients who acquired acute PQ intoxication were analyzed by plasma concentration monitoring. The plasma PQ concentrations were determined by high performance liquid chromatography (HPLC) which used 5-bromopyrimidine as internal standard and trichloroacetic acid-methanol (1:9) as protein precipitant. The liver, kidney and coagulation function were determined by automatic biochemical analyzer. According to plasma PQ concentration, 90 patients were divided into four groups: trace PQ group (<50ng/mL), low PQ group (<1000ng/mL), medium PQ group (1000-5000ng/mL) and high PQ group (>5000ng/mL). The clinical data from the four groups was statistically analyzed. The results showed the developed HPLC methods exhibited a high degree of accuracy and good linearity within 50-25000ng/mL (R=0.9998). The Spearman's correlation analysis showed PQ concentration had a strong relationship to total bilirubin, direct bilirubin, aspartic transaminase, urea nitrogen, prothrombin time, prothrombin activity, and international normalized ratio (P<0.01). The cured or survival PQ poisoned patients among the trace PQ group, the low PQ group, the medium PQ group, and the high PQ group were 19/19 (100%), 19/21 (90.47%), 11/25 (44.0%), and 0/25 (0%) respectively. The mean hospital days were (10.37±8.04), (18.76±12.06), (16.76±14.44), and (4.04±5.41) days respectively. The Cox regression analysis indicated that plasma PQ concentration was highly related to prognosis (P<0.05). In conclusion, no patient presenting with a PQ concentration over 5000ng/mL survived. The plasma PQ level is related to liver, kidney and coagulation function, which can be used as an important clinical index to judge the prognosis of PQ poisoned patients. Paraquat (PubChem CID: 15938), 5-bromopyrimidine (PubChem CID: 78344), acetonitrile (PubChem CID: 6342), sodium dihydrogen phosphate (PubChem CID: 23672064), sodium heptanesulfonate (PubChem CID: 23672332), methylprednisolone (PubChem CID: 6741), cyclophosphamide (PubChem CID: 2907). Copyright © 2016. Published by Elsevier Inc.

TK Modeler version 1.0, a Microsoft® Excel®-based modeling software for the prediction of diurnal blood/plasma concentration for toxicokinetic use.

PubMed

McCoy, Alene T; Bartels, Michael J; Rick, David L; Saghir, Shakil A

2012-07-01

TK Modeler 1.0 is a Microsoft® Excel®-based pharmacokinetic (PK) modeling program created to aid in the design of toxicokinetic (TK) studies. TK Modeler 1.0 predicts the diurnal blood/plasma concentrations of a test material after single, multiple bolus or dietary dosing using known PK information. Fluctuations in blood/plasma concentrations based on test material kinetics are calculated using one- or two-compartment PK model equations and the principle of superposition. This information can be utilized for the determination of appropriate dosing regimens based on reaching a specific desired C(max), maintaining steady-state blood/plasma concentrations, or other exposure target. This program can also aid in the selection of sampling times for accurate calculation of AUC(24h) (diurnal area under the blood concentration time curve) using sparse-sampling methodologies (one, two or three samples). This paper describes the construction, use and validation of TK Modeler. TK Modeler accurately predicted blood/plasma concentrations of test materials and provided optimal sampling times for the calculation of AUC(24h) with improved accuracy using sparse-sampling methods. TK Modeler is therefore a validated, unique and simple modeling program that can aid in the design of toxicokinetic studies. Copyright © 2012 Elsevier Inc. All rights reserved.

Carprofen pharmacokinetics in plasma and in control and inflamed canine tissue fluid using in vivo ultrafiltration.

PubMed

Messenger, K M; Wofford, J A; Papich, M G

2016-02-01

Measurement of unbound drug concentrations at their sites of action is necessary for accurate PK/PD modeling. The objective of this study was to determine the unbound concentration of carprofen in canine interstitial fluid (ISF) using in vivo ultrafiltration and to compare pharmacokinetic parameters of free carprofen concentrations between inflamed and control tissue sites. We hypothesized that active concentrations of carprofen would exhibit different dispositions in ISF between inflamed vs. normal tissues. Bilateral ultrafiltration probes were placed subcutaneously in six healthy Beagle dogs 12 h prior to induction of inflammation. Two milliliters of either 2% carrageenan or saline control was injected subcutaneously at each probe site, 12 h prior to intravenous carprofen (4 mg/kg) administration. Plasma and ISF samples were collected at regular intervals for 72 h, and carprofen concentrations were determined using HPLC. Prostaglandin E2 (PGE2 ) concentrations were quantified in ISF using ELISA. Unbound carprofen concentrations were higher in ISF compared with predicted unbound plasma drug concentrations. Concentrations were not significantly higher in inflamed ISF compared with control ISF. Compartmental modeling was used to generate pharmacokinetic parameter estimates, which were not significantly different between sites. Terminal half-life (T½) was longer in the ISF compared with plasma. PGE2 in ISF decreased following administration of carprofen. In vivo ultrafiltration is a reliable method to determine unbound carprofen in ISF, and that disposition of unbound drug into tissue is much higher than predicted from unbound drug concentration in plasma. However, concentrations and pharmacokinetic parameter estimates are not significantly different in inflamed vs. un-inflamed tissues. © 2015 John Wiley & Sons Ltd.

Spectroscopic studies of microwave plasmas containing hexamethyldisiloxane

NASA Astrophysics Data System (ADS)

Nave, A. S. C.; Mitschker, F.; Awakowicz, P.; Röpcke, J.

2016-10-01

Low-pressure microwave discharges containing hexamethyldisiloxane (HMDSO) with admixtures of oxygen and nitrogen, used for the deposition of silicon containing films, have been studied spectroscopically. Optical emission spectroscopy (OES) in the visible spectral range has been combined with infrared laser absorption spectroscopy (IRLAS). The experiments were carried out in order to analyze the dependence of plasma chemical phenomena on power and gas mixture at relatively low pressures, up to 50 Pa, and power values, up to 2 kW. The evolution of the concentration of the methyl radical, CH3, and of seven stable molecules, HMDSO, CH4, C2H2, C2H4, C2H6, CO and CO2, was monitored in the plasma processes by in situ IRLAS using tunable lead salt diode lasers (TDL) and external-cavity quantum cascade lasers (EC-QCL) as radiation sources. To achieve reliable values for the gas temperature inside and outside the plasma bulk as well as for the temperature in the plasma hot and colder zones, which are of great importance for calculation of species concentrations, three different methods based on emission and absorption spectroscopy data of N2, CH3 and CO have been used. In this approach line profile analysis has been combined with spectral simulation methods. The concentrations of the various species, which were found to be in the range between 1011 to 1015 cm-3, are in the focus of interest. The influence of the discharge parameters power, pressure and gas mixture on the molecular concentrations has been studied. To achieve further insight into general plasma chemical aspects the dissociation of the HMDSO precursor gas including its fragmentation and conversion to the reaction products was analyzed in detail.

Erythrocyte sedimentation rate and fibrinogen concentration of whole blood influences the cellular composition of platelet-rich plasma obtained from centrifugation methods.

PubMed

Yin, Wenjing; Xu, Zhengliang; Sheng, Jiagen; Xie, Xuetao; Zhang, Changqing

2017-09-01

Erythrocyte sedimentation rate (ESR), which reflects the sedimentation rate of platelets, leukocytes and erythrocytes in response to centrifugal force, may influence the cellular composition of platelet-rich plasma (PRP) obtained via centrifugation methods. However, no relevant studies have substantiated this. In the present study, blood was collected from 40 healthy volunteers and used to prepare PRP with two plasma-based preparation systems [YinPRP and Plasma Rich in Growth Factor (PRGF) systems] and two buffy coat-based systems (RegenPRP and WEGOPRP systems) in a single-donor model. Volumes of PRP and platelet-poor plasma (PPP) that were removed in the preparation process were recorded. Analyses of ESR, haematocrit, C-reaction protein, coagulation, serum glucose and serum lipid of the whole blood used for PRP preparation were performed to evaluate the levels of ESR and the factors known to influence it. Whole blood analysis was performed to evaluate the cellular composition of PRP. Results demonstrated that there were marked positive correlations between the ESR of the whole blood used for PRP preparation and PPP removal efficiencies, platelet concentrations, platelet capture efficiencies and platelet enrichment factors of PRP formulations obtained from plasma-based systems, and PRP yield efficiency of RegenPRP and PPP removal efficiency of WEGOPRP. Furthermore, there were marked negative correlations between ESR and concentrations and enrichment factors of platelets, leukocytes and erythrocytes of RegenPRP. Fibrinogen concentration of the whole blood, which had a marked positive correlation with ESR, also influenced the cellular composition of PRP. These findings may increase the understanding of PRP preparation and provide substantial evidence for the individualised optimisation of PRP preparation systems used in clinical practice.

Dispositional study of opioids in mice pretreated with sympathomimetic agents.

PubMed

Dambisya, Y M; Chan, K; Wong, C L

1992-08-01

Brain and plasma levels of morphine and codeine were determined by an assay method involving solid-phase extraction and ion-pair reversed phase HPLC. Detection was by a variable wavelength UV-detector (for codeine) and an amperometric electro-chemical detector (for morphine) coupled in series. Ephedrine or phenylpropanolamine pretreatment did not interfere with the plasma disposition of morphine, evidenced by overlapping plasma concentration-time profiles. Brain opioid levels were equally unaffected by sympathomimetic pretreatment. The relative ratios of brain to plasma concentrations at the time corresponding to the respective peak anti-nociceptive activity for morphine and codeine revealed no significant differences. It is concluded that single doses of ephedrine and phenylpropanolamine do not affect the disposition of morphine and codeine in mice.

Evaluation of on-line desalter-inductively coupled plasma-mass spectrometry system for determination of Cr(III), Cr(VI), and total chromium concentrations in natural water and urine samples

NASA Astrophysics Data System (ADS)

Sun, Y. C.; Lin, C. Y.; Wu, S. F.; Chung, Y. T.

2006-02-01

We have developed a simple and convenient method for the determination of Cr(III), Cr(VI), and the total chromium concentrations in natural water and urine samples that use a flow injection on-line desalter-inductively coupled plasma-mass spectrometry system. When using aqueous ammonium chloride (pH 8) as the stripping solution, the severe interference from sodium in the matrix can be eliminated prior to inductively coupled plasma-mass spectrometry measurement, and the Cr(VI) level can be determined directly. To determine the total concentration of Cr in natural water and urine samples, we used H 2O 2 or HNO 3 to decompose the organic matter and convert all chromium species into the Cr(VI) oxidation state. To overcome the spectral interference caused by the matrix chloride ion in the resulting solutions, we employed cool plasma to successfully suppress chloride-based molecular ion interference during the inductively coupled plasma-mass spectrometry measurement. By significantly eliminating interference from the cationic and anionic components in the matrices prior to the inductively coupled plasma-mass spectrometry measurement, we found that the detection limit reached 0.18 μg L - 1 (based on 3 sigma). We validated this method through the analysis of the total chromium content in two reference materials (NIST 1643c and 2670E) and through measuring the recovery in spiked samples.

Maternal choline status during pregnancy, but not that of betaine, is related to antenatal mental well-being: the Growing Up in Singapore Towards healthy Outcomes cohort

PubMed Central

van Lee, Linde; Quah, Phaik Ling; Saw, Seang Mei; Yap, Fabian KP; Godfrey, Keith M; Chong, Yap Seng; Meaney, Michael J; Chen, Helen; Chong, Mary Foong-Fong

2017-01-01

Background Choline and betaine status have previously been associated with symptoms of depression. However, the relation of maternal plasma choline and betaine concentrations in pregnancy to peripartum maternal mood is unknown. Methods Maternal plasma choline and betaine concentrations (µmol/L) were measured at 26-28 weeks gestation in the GUSTO mother-offspring cohort. Participants completed the State-Trait Anxiety Inventory (STAI) and Edinburgh Postnatal Depression Scale (EDPS) at 26-28 weeks gestation (n=949) and at 3 months postnatal (n=689): higher scores are indicative of more symptoms of anxiety and depression. Multivariate linear regression models were used to estimate the association of choline and betaine with ante- and postnatal mental well-being adjusting for covariates. Results Mean (SD) antenatal plasma choline and betaine concentrations were 9.2 µmol/L (1.6) and 13.1 µmol/L (2.7), respectively. Plasma choline concentrations were positively associated with antenatal depressive [β=0.24 EPDS score (95% CI 0.05, 0.43) per µmol/L] and anxiety symptoms [β=0.46 STAI-state score (95% CI 0.03, 0.88) per µmol/L] adjusting for covariates. Plasma betaine concentrations were not associated with antenatal depression or anxiety symptoms. No associations were observed between pregnancy choline or betaine and postnatal mental well-being. Conclusion This study suggests that higher maternal plasma choline status during pregnancy is associated with more symptoms of antenatal depression and anxiety, while plasma betaine concentrations showed no associations. No associations were observed for postnatal mental well-being. Prospective studies are required to replicate these findings and further examine the direction of causality and possible biological mechanisms. PMID:28471488

Pre-formulation studies of resveratrol

PubMed Central

Robinson, Keila; Mock, Charlotta; Liang, Dong

2015-01-01

Context Resveratrol, a natural compound found in grapes, has potential chemotherapy effects but very low oral bioavailability in humans. Objective To evaluate the solubility, pH stability profile, plasma protein binding (PPB) and stability in plasma for resveratrol. Methods Solubility of resveratrol was measured in 10 common solvents at 25 °C using HPLC. The solution state pH stability of resveratrol was assessed in various United States Pharmacopeia buffers ranging from pH 2 to 10 for 24 h at 37 °C. Samples were analyzed up to 24 h. Human PPB was determined using ultracentrifugation technique. Standard solutions of drug were spiked to blank human plasma to yield final concentrations of 5, 12.5 or 25 µg/mL for determination. Finally, stability of resveratrol in human and rat plasma was also assessed at 37 °C. Aliquots of blank plasma were spiked with a standard drug concentration to yield final plasma concentration of 50 µg/mL. Samples were analyzed for resveratrol concentration up to 96 h. Results Resveratrol has wide solubility ranging from 0.05 mg/mL in water to 374 mg/mL in polyethylene glycol 400 (PEG-400). Resveratrol is relatively stable above pH 6 and has maximum degradation at pH 9. The mean PPB of resveratrol is 98.3%. Resveratrol degrades in human and rat plasma in a first-order process with mean half lives of 54 and 25 h, respectively. Conclusion Resveratrol is more soluble in alcohol and PEG-400 and stable in acidic pH. It binds highly to plasma proteins and degrades slower in human then rat plasma. PMID:25224342

EGFR mutation status of paired cerebrospinal fluid and plasma samples in EGFR mutant non-small cell lung cancer with leptomeningeal metastases.

PubMed

Zhao, Jing; Ye, Xin; Xu, Yan; Chen, Minjiang; Zhong, Wei; Sun, Yun; Yang, Zhenfan; Zhu, Guanshan; Gu, Yi; Wang, Mengzhao

2016-12-01

Central nervous system (CNS) is the prevalent site for metastases in epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-relapsed NSCLC patients. To understand the EGFR mutation status in paired cerebrospinal fluid (CSF) and plasma samples after EGFR-TKI treatment failure might be useful to guide the treatment of intra- and extracranial tumors in those patients. Paired CSF and plasma samples were collected from seven NSCLC patients with CNS metastases after EGFR-TKI failure. EGFR mutations were tested by amplification refractory mutation system (ARMS) and droplet digital PCR (ddPCR) methods. Gefitinib concentrations were evaluated by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). EGFR mutations were detected in all seven CSF samples, including three of E19-Del, three of L858R and one of E19-Del&T790M by both methods. On the other hand, majority of the matched plasma samples (5/7) were negative for EGFR mutations by both methods. The other two plasma samples were positive for E19-Del&T790M by ddPCR, and one of them had undetectable T790M by ARMS. Gefitinib concentration in CSF was much lower than that in plasma (mean CSF/plasma ratio: 1.8 %). After EGFR-TKI failure, majority of the NSCLC patients with CNS metastases remained positive detection of EGFR sensitive mutations in CSF, but much less detection in the matched plasma. Significantly low exposure of gefitinib in CSF might explain the intracranial protection of the EGFR sensitive mutation positive tumor cells.

Fluorophore-based sensor for oxygen radicals in processing plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhury, Faraz A.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu; Sabat, Grzegorz

2015-11-15

A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye thatmore » is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye.« less

Elimination of diazinon insecticide from cucumber surface by atmospheric pressure air-dielectric barrier discharge plasma.

PubMed

Dorraki, Naghme; Mahdavi, Vahideh; Ghomi, Hamid; Ghasempour, Alireza

2016-12-06

The food industry is in a constant search for new technologies to improve the commercial sterilization process of agricultural commodities. Plasma treatment may offer a novel and efficient method for pesticide removal from agricultural product surfaces. To study the proposed technique of plasma food treatment, the degradation behavior of diazinon insecticide by air-dielectric barrier discharge (DBD) plasma was investigated. The authors studied the effect of different plasma powers and treatment times on pesticide concentration in liquid form and coated on the surface of cucumbers, where the diazinon residue was analyzed with mass spectroscopy gas chromatography. Our results suggest that atmospheric pressure air-DBD plasma is potentially effective for the degradation of diazinon insecticide, and mainly depends on related operating parameters, including plasma treatment time, discharge power, and pesticide concentrations. Based on the interaction between reactive oxygen species and electrons in the plasma with the diazinon molecule, two degradation pathway of diazinon during plasma treatment are proposed. It was also found that produced organophosphate pesticides are harmless and less hazardous compounds than diazinon.

Synthesis of the flavonoid 3',4',5'-trimethoxyflavonol and its determination in plasma and tissues of mice by HPLC with fluorescence detection.

PubMed

Britton, Robert G; Fong, Isabel; Saad, Shaban; Brown, Karen; Steward, William P; Gescher, Andreas; Sale, Stewart

2009-04-01

3',4',5'-Trimethoxyflavonol (TMFol) was synthesized as a potential colorectal cancer chemopreventive agent. An HPLC method for determination for TMFol in murine plasma and tissues was developed and validated using human plasma. Analyte was separated (C(18) column; fluorescence detection 330nm excitation, 440nm emission) using 69% methanol and 0.1M ammonium acetate buffer (pH 5.1) as mobile phase. The method was linear for 50-2500ng/ml plasma and 0.05-10microg/g tissue (r>0.99). TMFol was recovered from plasma or tissues using solid phase columns or organic solvent protein precipitation, respectively. Recovery at low, medium and high concentrations was 97.6-107.3%, with inter- and intra-day coefficients of variation of <10%. The lower limit of quantitation for plasma was 50ng/ml. The method was applied to measure steady-state TMFol plasma and tissue levels in mice which received dietary TMFol (0.2%).

Liquid chromatography/tandem mass spectrometry method for quantitative estimation of polyethylene glycol 400 and its applications.

PubMed

Vijaya Bhaskar, V; Middha, Anil; Tiwari, Sudhir; Shivakumar, Savithiri

2013-05-01

A rapid sensitive and selective MRM based method for the determination of polyethylene glycol 400 (PEG 400) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC-MS/MS). PEG 400 and telmisartan (Internal standard) were extracted from rat plasma with acetonitrile and analysed on C18 column (Waters Xbridge, 50×4.6 mm, 3.5 μm) with the mobile phase (A - 0.1% formic acid in water; B - methanol). A generic gradient method with a short run time of 3.5 min was developed for the analysis of PEG 400. A total of nine oligomers were identified for PEG 400. The most abundant ions corresponding to PEG 400 oligomers at m/z 327, 371, 432, 476, 520, 564, 608, 652 and 696 with daughter ion at m/z 89 were selected for multiple reaction monitoring (MRM) in electrospray mode of ionisation. Analyte peak area of the oligomers was summed up to calculate the plasma concentrations of total PEG 400. The standard curve was linear (0.9954) over the concentration range of 1.01-1013.40 μg/mL. The lower limit of quantitation for PEG 400 was 1.01 μg/mL using 50 μL plasma. The coefficient of variation and relative error for inter and intraassay at three QC levels were 2.31-13.34 and -7.99 to 0.37, respectively. The method was validated for various parameters such as extraction recovery, matrix effect, autosampler stability, benchtop stability, freeze thaw stability, long term stability and was proved to be consistent across three QC levels with overall %CV less than 15. The developed method was successfully applied to the absolute bioavailability study of PEG 400 in male Sprague Dawley rats. Plasma concentrations of PEG 400 was measured after administration through oral and intravenous routes in male Sprague Dawley rats at a dose of 3.38 g/kg. Pharmacokinetic (PK) parameters were characterised by performing the analysis using Phoenix Winnonlin software (v 6.3). PEG 400 has good oral bioavailability with mean absolute bioavailability of 47.23%. Plasma concentration profile/PK parameters of PEG 400 was established in both intravenous and oral routes, which helps to qualify the analytical batch of NCEs having spiky plasma concentration profiles/erratic results. Purity of the PEG 400 oligomers was estimated using ELSD detection. Differences in pharmacokinetics of oligomers was studied. It was found that with increase in molecular weight of the oligomer, a decrease in absolute bioavailability was observed. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

23RD International Conference on Phenomena in Ionized Gases, Volume 3

DTIC Science & Technology

1998-12-01

discharges, and high pressure glows; arcs; high frequency discharges; ionospheric magnetospheric, and astrophysical plasmas; plasma diagnostic methods ...kf) in pulse reflectometry. Second, it different frequencies , and an Abel inversion is gives a quantitative model of the behaviour of the wave... design V method in the case of narrow mutual pitch of surface electrodes for high concentration ozone generation. 2. Experimental setup 20 The electrode

Effect of intravenous drug administration mode on drug distribution in a tumor slab: a finite Fourier transform analysis.

PubMed

Subramaniam, B; Claudius, J S

1990-03-08

Cancer therapy using chemotherapeutic drugs frequently involves injection of the drug into the body through some intravenous mode of administration, viz, continuous (drip) infusion or single/multiple bolus injection(s). An understanding of the effect of the various modes of administration upon tumor penetration of drug is essential to rational design of drug therapy. This paper investigates drug penetration into a model tumor of slab geometry (between two capillaries) in which the overall transport rate of drug is limited by intra-tumor transport characterized by an effective diffusion coefficient. Employing the method of Finite Fourier Transforms (FFT), analytical solutions have been obtained for transient drug distribution in both the plasma and the tumor following three modes of administration, viz, continuous infusion, single bolus injection and equally-spaced equal-dose multiple bolus injections, of a given amount of drug. The qualitative trends exhibited by the plasma drug distribution profiles are consistent with reported experimental studies. Two concepts, viz, the dimensionless decay constant and the plasma/tumor drug concentration trajectories, are found to be particularly useful in the rational design of drug therapy. The dimensionless decay constant provides a measure of the rate of drug decay in the plasma relative to the rate of drug diffusion into the tumor and is thus characteristic of the tumor/drug system. The magnitude of this parameter dictates the choice of drug administration mode for minimizing drug decay in the plasma while simultaneously maximizing drug transport into the tumor. The concentration trajectories provide a measure of the plasma drug concentration relative to the tumor drug concentration at various times following injection. When the tumor drug concentration exceeds the plasma drug concentration, the drug will begin to diffuse out of the tumor. Knowledge of the time at which this diffusion reversal occurs is especially useful for optimum scheduling of subsequent bolus injections in a multiple bolus dosing regimen. There are no reported applications of the FFT method to solve repeated input functions in either the chemical engineering or pharmaceutical science literature. Thus, the application of FFT method to solve multiple bolus injections is a unique one. Use of this FFT based analysis as a predictor tool can limit the number of costly experiments which are being done now to achieve this purpose. Even though the model in its present form is simplified, the analysis thereof has nevertheless led to a better understanding of the various factors that must be taken into account for rational design of drug therapy.

Concentrated autologous plasma protein: a biochemically neutral solder for tissue welding.

PubMed

Stewart, R B; Bleustein, C B; Petratos, P B; Chin, K C; Poppas, D P; Kung, R T

2001-01-01

Xenographic or allographic serum protein solders used for laser welding may have immunologic and/or pathogenic complications. The objective of these studies was to develop a safe, autologous solder. Five methods of preparing concentrated autologous plasma protein solder (CAPPS) were evaluated. Next, the CAPPS was evaluated via (1) thermal denaturation studies using differential scanning calorimetry, (2) tissue welding studies to characterize both acute and healing properties. The optimal concentration method to produce CAPPS rapidly was a dialysis method using chemical (osmotic) forces. The CAPPS showed similar denaturation profiles to serum albumin (SA) solders. Acutely, CAPPS provided comparable breaking strengths to SA solders. At 7 days, there was no significant difference in breaking strength or histology between 50% human SA solder and CAPPS (using a porcine skin model). These studies demonstrate that the CAPPS system provides acceptable acute and chronic properties for laser welding. Copyright 2001 Wiley-Liss, Inc.

Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF).

PubMed

Dohan Ehrenfest, David M; Rasmusson, Lars; Albrektsson, Tomas

2009-03-01

The topical use of platelet concentrates is recent and its efficiency remains controversial. Several techniques for platelet concentrates are available; however, their applications have been confusing because each method leads to a different product with different biology and potential uses. Here, we present classification of the different platelet concentrates into four categories, depending on their leucocyte and fibrin content: pure platelet-rich plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; leucocyte- and platelet-rich plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan or GPS PRP; pure plaletet-rich fibrin (P-PRF), such as Fibrinet; and leucocyte- and platelet-rich fibrin (L-PRF), such as Choukroun's PRF. This classification should help to elucidate successes and failures that have occurred so far, as well as providing an objective approach for the further development of these techniques.

Liquid chromatographic determination of florfenicol in the plasma of multiple species of fish

USGS Publications Warehouse

Vue, C.; Schmidt, L.J.; Stehly, G.R.; Gingerich, W.H.

2002-01-01

A simple method was developed for determining florfenicol concentration in a small volume (250 mul) of plasma from five phylogenetically diverse species of freshwater fish. Florfenicol was isolated from the plasma matrix through C-18 solid-phase extraction and quantified by reversed-phase high-performance liquid chromatography with UV detection. The accuracy (84-104%), precision (%RSDless than or equal to8), and sensitivity (quantitation limit <30 ng/ml) of the method indicate its usefulness for conducting pharmacokinetic studies on a variety of freshwater fish. Published by Elsevier Science B.V.

Distribution of Parvovirus B19 DNA in Blood Compartments and Persistence of Virus in Blood Donors

PubMed Central

Lee, Tzong-Hae; Kleinman, Steven H.; Wen, Li; Montalvo, Lani; Todd, Deborah S.; Wright, David J.; Tobler, Leslie H.; Busch, Michael P.

2013-01-01

Introduction Because the receptor for Parvovirus B19 (B19V) is on erythrocytes, we investigated B19V distribution in blood by in-vitro spiking experiments and evaluated viral compartmentalization and persistence in natural infection. Methods Two whole blood protocols (ultracentrifugation and a rapid RBC lysis/removal protocol) were evaluated using quantitative real-time PCR. Whole blood (WB) was spiked with known concentrations of B19V and recovery in various blood fractions was determined. The rapid RBC lysis/removal protocol was then used to compare B19V concentrations in 104 paired whole blood and plasma samples collected longitudinally from 43 B19V infected donors with frozen specimens in the REDS Allogeneic Donor and Recipient Repository (RADAR). Results In B19V spiking experiments, ~one-third of viral DNA was recovered in plasma and two-thirds was loosely bound to erythrocytes. In the IgM positive stage of infection in blood donors when plasma B19V DNA concentrations were > 100 IU/mL, median DNA concentrations were ~30-fold higher in WB than in plasma. In contrast, when IgM was absent and when the B19V DNA concentration was lower, the median whole blood to plasma ratio was ~1. Analysis of longitudinal samples demonstrated persistent detection of B19V in WB but declining ratios of WB/plasma B19V with declining plasma VL levels and loss of IgM-reactivity. Conclusions The WB/plasma B19V DNA ratio varies by stage of infection. Further study is required to determine if this is related to the presence of circulating DNA-positive erythrocytes derived from B19V infected erythroblasts, B19V-specific IgM mediated binding of virus to cells, or other factors. PMID:21303368

Plasma Alkylresorcinols, Biomarkers of Whole-Grain Wheat and Rye Intake, and Incidence of Colorectal Cancer

PubMed Central

2014-01-01

Background Few studies have investigated the association between whole-grain intake and colorectal cancer. Because whole-grain intake estimation might be prone to measurement errors, more objective measures (eg, biomarkers) could assist in investigating such associations. Methods The association between alkylresorcinols, biomarkers of whole-grain rye and wheat intake, and colorectal cancer incidence were investigated using prediagnostic plasma samples from colorectal cancer case patients and matched control subjects nested within the European Prospective Investigation into Cancer and Nutrition. We included 1372 incident colorectal cancer case patients and 1372 individual matched control subjects and calculated the incidence rate ratios (IRRs) for overall and anatomical subsites of colorectal cancer using conditional logistic regression adjusted for potential confounders. Regional differences (Scandinavia, the Mediterranean, Central Europe) were also explored. Results High plasma total alkylresorcinol concentration was associated with lower incidence of distal colon cancer; the adjusted incidence rate ratio of distal colon cancer for the highest vs lowest quartile of plasma total alkylresorcinols was 0.48 (95% confidence interval [CI] = 0.28 to 0.83). An inverse association between plasma total alkylresorcinol concentrations and colon cancer was found for Scandinavian participants (IRR per doubling = 0.83; 95% CI = 0.70 to 0.98). However, plasma total alkylresorcinol concentrations were not associated with overall colorectal cancer, proximal colon cancer, or rectal cancer. Plasma alkylresorcinols concentrations were associated with colon and distal colon cancer only in Central Europe and Scandinavia (ie, areas where alkylresorcinol levels were higher). Conclusions High concentrations of plasma alkylresorcinols were associated with a lower incidence of distal colon cancer but not with overall colorectal cancer, proximal colon cancer, and rectal cancer. PMID:24317181

Mapping Fifteen Trace Elements in Human Seminal Plasma and Sperm DNA.

PubMed

Ali, Sazan; Chaspoul, Florence; Anderson, Loundou; Bergé-Lefranc, David; Achard, Vincent; Perrin, Jeanne; Gallice, Philippe; Guichaoua, Marie

2017-02-01

Studies suggest a relationship between semen quality and the concentration of trace elements in serum or seminal plasma. However, trace elements may be linked to DNA and capable of altering the gene expression patterns. Thus, trace element interactions with DNA may contribute to the mechanisms for a trans-generational reproductive effect. We developed an analytical method to determine the amount of trace elements bound to the sperm DNA, and to estimate their affinity for the sperm DNA by the ratio: R = Log [metal concentration in the sperm DNA/metal concentration in seminal plasma]. We then analyzed the concentrations of 15 trace elements (Al, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Ti, V, Zn, As, Sb, and Se) in the seminal plasma and the sperm DNA in 64 normal and 30 abnormal semen specimens with Inductively Coupled Plasma/Mass Spectrometry (ICP-MS). This study showed all trace elements were detected in the seminal plasma and only metals were detected in the sperm DNA. There was no correlation between the metals' concentrations in the seminal plasma and the sperm DNA. Al had the highest affinity for DNA followed by Pb and Cd. This strong affinity is consistent with the known mutagenic effects of these metals. The lowest affinity was observed for Zn and Ti. We observed a significant increase of Al linked to the sperm DNA of patients with oligozoospermia and teratozoospermia. Al's reproductive toxicity might be due to Al linked to DNA, by altering spermatogenesis and expression patterns of genes involved in the function of reproduction.

Influence of P-glycoprotein modulation on plasma concentrations and pharmacokinetics of orally administered prednisolone in dogs.

PubMed

Van der Heyden, Sara; Croubels, Siska; Gadeyne, Caroline; Ducatelle, Richard; Daminet, Sylvie; Murua Escobar, Hugo; Sterenczak, Katharina; Polis, Ingeborgh; Schauvliege, Stijn; Hesta, Myriam; Chiers, Koen

2012-06-01

To evaluate the impact of modulation of the membrane-bound efflux pump P-glycoprotein (P-gp) on plasma concentrations of orally administered prednisolone in dogs. 7 healthy adult Beagles. Each dog received 3 treatments (control [no treatment], rifampicin [100 mg/d, PO, for 21 days, as an inducer of P-gp], and ketoconazole [100 mg/d, PO, for 21 days, as an inhibitor of P-gp]). A single dose of prednisolone (1 mg/kg, PO) was administered on day 8 of each treatment period. There was a 7-day washout period between subsequent treatments. Plasma concentrations of prednisolone were determined by use of a validated liquid chromatography-tandem mass spectrometry method. Duodenum and colon biopsy specimens were obtained endoscopically from anesthetized dogs and assessed for P-gp protein labeling via immunohistochemical analysis and mRNA quantification via real-time PCR assay. Total fecal collection was performed for evaluation of effects of P-gp modulation on digestion of nutrients. Rifampicin treatment upregulated duodenal P-gp in dogs and significantly reduced the area under the plasma concentration-time curve of prednisolone. Ketoconazole typically downregulated expression of duodenal P-gp, with a subsequent increase in the area under the plasma concentration-time curve of prednisolone. There was a noticeable interindividual difference in response. Digestion of nutrients was not affected. Modulation of P-gp expression influenced plasma concentrations of prednisolone after oral administration in dogs. Thus, treatment response to prednisolone may be influenced by coadministration of P-gp-modulating medications or feed ingredients.

GC-MS Quantification Method for Mephedrone in Plasma and Urine: Application to Human Pharmacokinetics.

PubMed

Olesti, Eulàlia; Pujadas, Mitona; Papaseit, Esther; Pérez-Mañá, Clara; Pozo, Óscar J; Farré, Magí; de la Torre, Rafael

2017-03-01

Increasing consumption has been observed among young people of new psychoactive substances, including synthetic cathinone derivatives. The most well known of these is mephedrone whose use has been related to acute intoxication and fatality. Several methods able to detect mephedrone have been reported, although to date, none have been applied to human pharmacokinetic studies in a controlled setting. We developed a gas chromatography-mass spectrometry technique for mephedrone quantification in human plasma and urine. Plasma after deproteinization and urine were submitted to a liquid-liquid extraction and derivatization of the extract with MSTFA prior to analysis. Calibration curves covered concentration ranges in plasma between 5 and 300 ng/mL and in urine between 20 and 1,500 ng/mL. The method has been successfully applied to biological samples obtained from a pilot clinical trial intended to evaluate the human pharmacology of mephedrone and its relative bioavailability and pharmacokinetics. Six healthy males were administered 150 mg of mephedrone by the oral route in a randomized, double-blind, cross-over controlled trial. Peak plasma concentration (Cmax = 122.6 ± 32.9 ng/mL) was reached at 1 hour (0.5-2 h) post-drug administration. Mephedrone showed a rapid elimination half-life (t1/2 = 2.2 h) compared to other psychostimulants. Less than 15% of the dose was excreted in urine as a free-form. Mephedrone concentrations displayed a relevant inter-subject variability. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Plasma folate levels in early to mid pregnancy after a nation-wide folic acid supplementation program in areas with high and low prevalence of neural tube defects in China.

PubMed

Liu, Jufen; Gao, Lili; Zhang, Yali; Jin, Lei; Li, Zhiwen; Zhang, Le; Meng, Qinqin; Ye, Rongwei; Wang, Linlin; Ren, Aiguo

2015-06-01

Folic acid supplementation is recommended for all women of child-bearing age to prevent neural tube defects (NTDs). A nation-wide folic acid supplementation program was implemented in rural areas of China since 2009; however, changes in plasma folate levels in pregnant women were unknown. A cross-sectional survey was conducted in 2011 to 2012, with 1736 pregnant women enrolled, and results were compared with a previous survey in 2002 to 2004. A microbiological method was used to determine plasma folate levels. Preprogram and postprogram median plasma folate concentrations were compared while stratified by prevalence of NTDs and residence. In the high NTD prevalence population, plasma folate concentration increased to 33.4 (18.7, 58.4) nmol/L in the postprogram sample, which is 2.9 times of the preprogram. In the low NTD prevalence population, plasma folate increased to 67.9 (44.5, 101.9) nmol/L, which is 1.9 times of the preprogram. Gaps remained in plasma folate levels with respect to prevalence of NTDs and residence. Folic acid supplementation has a strong impact on plasma folate concentrations. Earlier supplementation (before the last menstrual period), increased supplementation frequency and more total days of supplementation were associated with a higher plasma folate concentration as demonstrated in both the high- and low-prevalence populations. Plasma folate levels among pregnant Chinese women increased dramatically after the nation-wide folic acid supplementation program in both rural and urban areas, and in populations of high and low NTD prevalence. The nation-wide program should have a component to ensure that supplementation begins before pregnancy. © 2015 Wiley Periodicals, Inc.

Bioavailability of ambroxol sustained release preparations. Part II: Single and multiple oral dose studies in man.

PubMed

Janssen, T J; Guelen, P J; Vree, T B; Botterblom, M H; Valducci, R

1988-01-01

The bioavailability of a new ambroxol sustained release preparation (75 mg) based on a dialyzing membrane for controlled release was studied in healthy volunteers after single and multiple oral dose in comparison with a standard sustained release formulation in a cross-over study under carefully controlled conditions. Plasma concentrations of ambroxol were measured by means of a HPLC method. Based on AUC data both preparations are found to be bioequivalent, but show different plasma concentration profiles. The test preparation showed a more pronounced sustained release profile than the reference preparation (single dose) resulting in significantly higher steady state plasma levels.

Quantification of leptin in seminal plasma of buffalo bulls and its correlation with antioxidant status, conventional and computer-assisted sperm analysis (CASA) semen variables.

PubMed

Kumar, Pradeep; Saini, Monika; Kumar, Dharmendra; Jan, M H; Swami, Dheer Singh; Sharma, R K

2016-03-01

The present study is the first to quantify leptin in seminal plasma of buffalo and investigate its relationship with seminal attributes. Ten ejaculates each from 10 Murrah buffalo bulls were collected. Semen quality variables such as semen volume, sperm concentration, sperm abnormalities, membrane integrity, antioxidant enzyme activities (superoxide dismutase, catalase and total antioxidant capacity), malondialdehyde (MDA) concentration, as well as sperm kinetics and motility variables were evaluated. The leptin concentration in serum and seminal plasma were estimated by the ELISA method. Bulls were classified in two groups on the basis of sperm concentration with Group I having >800 million sperm/mL and Group II <500 million sperm/mL. Greater (P<0.05) mean sperm abnormalities, seminal leptin concentrations and MDA concentrations were recorded in Group II than Group I. The seminal leptin was positively correlated with sperm abnormalities and MDA concentration while being negatively correlated with sperm concentration, but there was no correlation with sperm kinetic and motility variables, sperm membrane integrity and seminal plasma antioxidant enzyme activity. Thus, the data suggest that seminal leptin has a role in spermatogenesis and can be used as a marker for spermatogenesis to predict the capacity of buffalo bulls for semen production. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of sugar-sweetened beverages on plasma acylation stimulating protein, leptin, and adiponectin: Relationships with metabolic outcomes

USDA-ARS?s Scientific Manuscript database

OBJECTIVE: The effects of fructose and glucose consumption on plasma acylation stimulating protein (ASP), adiponectin, and leptin concentrations relative to energy intake, body weight, adiposity, circulating triglycerides, and insulin sensitivity were determined. DESIGN AND METHODS: Thirty two over...

Automated and sensitive method for the determination of formoterol in human plasma by high-performance liquid chromatography and electrochemical detection.

PubMed

Campestrini, J; Lecaillon, J B; Godbillon, J

1997-12-19

An automated high-performance liquid chromatography (HPLC) method for the determination of formoterol in human plasma with improved sensitivity has been developed and validated. Formoterol and CGP 47086, the internal standard, were extracted from plasma (1 ml) using a cation-exchange solid-phase extraction (SPE) cartridge. The compounds were eluted with pH 6 buffer solution-methanol (70:30, v/v) and the eluate was further diluted with water. An aliquot of the extract solution was injected and analyzed by HPLC. The extraction, dilution, injection and chromatographic analysis were combined and automated using the automate (ASPEC) system. The chromatographic separations were achieved on a 5 microm, Hypersil ODS analytical column (200 mm x 3 mm I.D.), using (pH 6 phosphate buffer, 0.035 M + 20 mg/l EDTA)-MeOH-CH3CN (70:25:5, v/v/v) as the mobile phase at a flow-rate of 0.4 ml/min. The analytes were detected with electrochemical detection at an operating potential of +0.63 V. Intra-day accuracy and precision were assessed from the relative recoveries of calibration/quality control plasma samples in the concentration range of 7.14 to 238 pmol/l of formoterol base. The accuracy over the entire concentration range varied from 81 to 105%, and the precision (C.V.) ranged from 3 to 14%. Inter-day accuracy and precision were assessed in the concentration range of 11.9 to 238 pmol/l of formoterol base in plasma. The accuracy over the entire concentration range varied from 98 to 109%, and precision ranged from 8 to 19%. At the limit of quantitation (LOQ) of 11.9 pmol/l for inter-day measurements, the recovery value was 109% and C.V. was 19%. As shown from intra-day accuracy and precision results, favorable conditions (a newly used column, a newly washed detector cell and moderate residual cell current level) allowed us to reach a LOQ of 7.14 pmol/l of formoterol base (3 pg/ml of formoterol fumarate dihydrate). Improvement of the limit of detection by a factor of about 10 was reached as compared to the previously described methods. The method has been applied for quantifying formoterol in plasma after 120 microg drug inhalation to volunteers. Formoterol was still measurable at 24 h post-dosing in most subjects and a slow elimination of formoterol from plasma beyond 6-8 h after inhalation was demonstrated for the first time thanks to the sensitivity of the method.

Evaluation of optimized bronchoalveolar lavage sampling designs for characterization of pulmonary drug distribution.

PubMed

Clewe, Oskar; Karlsson, Mats O; Simonsson, Ulrika S H

2015-12-01

Bronchoalveolar lavage (BAL) is a pulmonary sampling technique for characterization of drug concentrations in epithelial lining fluid and alveolar cells. Two hypothetical drugs with different pulmonary distribution rates (fast and slow) were considered. An optimized BAL sampling design was generated assuming no previous information regarding the pulmonary distribution (rate and extent) and with a maximum of two samples per subject. Simulations were performed to evaluate the impact of the number of samples per subject (1 or 2) and the sample size on the relative bias and relative root mean square error of the parameter estimates (rate and extent of pulmonary distribution). The optimized BAL sampling design depends on a characterized plasma concentration time profile, a population plasma pharmacokinetic model, the limit of quantification (LOQ) of the BAL method and involves only two BAL sample time points, one early and one late. The early sample should be taken as early as possible, where concentrations in the BAL fluid ≥ LOQ. The second sample should be taken at a time point in the declining part of the plasma curve, where the plasma concentration is equivalent to the plasma concentration in the early sample. Using a previously described general pulmonary distribution model linked to a plasma population pharmacokinetic model, simulated data using the final BAL sampling design enabled characterization of both the rate and extent of pulmonary distribution. The optimized BAL sampling design enables characterization of both the rate and extent of the pulmonary distribution for both fast and slowly equilibrating drugs.

Laser-induced plasma characterization through self-absorption quantification

NASA Astrophysics Data System (ADS)

Hou, JiaJia; Zhang, Lei; Zhao, Yang; Yan, Xingyu; Ma, Weiguang; Dong, Lei; Yin, Wangbao; Xiao, Liantuan; Jia, Suotang

2018-07-01

A self-absorption quantification method is proposed to quantify the self-absorption degree of spectral lines, in which plasma characteristics including electron temperature, elemental concentration ratio, and absolute species number density can be deduced directly. Since there is no spectral intensity involved in the calculation, the analysis results are independent of the self-absorption effects and the additional spectral efficiency calibration is not required. In order to evaluate the practicality, the limitation for application and the precision of this method are also discussed. Experimental results of aluminum-lithium alloy prove that the proposed method is qualified to realize semi-quantitative measurements and fast plasma characteristics diagnostics.

Investigation on physicochemical properties of plasma-activated water for the application of medical device sterilization

NASA Astrophysics Data System (ADS)

Abuzairi, Tomy; Ramadhanty, Savira; Puspohadiningrum, Dini Fithriaty; Ratnasari, Anita; Poespawati, Nji Raden; Purnamaningsih, Retno Wigajatri

2018-02-01

Plasma activated water (PAW) is a new approach to bacterial inactivation while ensuring safety and maintaining the properties of the material sterilized. Reported research imply that PAW has been effective for inactivation of bacteria. In this paper, plasma treatment using atmospheric pressure plasma was demonstrated. Physicochemical properties such as pH, temperature, ORP, and nitrite concentration were assessed. The results suggest that plasma treatment causes acidification on water and generate reactive species, creating an environment suitable for killing bacteria. Therefore, plasma activated water is an assuring method for medical devices sterilization.

Vitamin D insufficiency is common in Indian mothers but is not associated with gestational diabetes or variation in newborn size

PubMed Central

Farrant, Hannah JW; Krishnaveni, Ghattu V; Hill, Jacqueline C; Boucher, Barbara J; Fisher, David J; Noonan, Kate; Osmond, Clive; Veena, Sargoor R; Fall, Caroline HD

2009-01-01

Background/objectives: Vitamin D is required for bone growth and normal insulin secretion. Maternal hypovitaminosis D may impair fetal growth and increase the risk of gestational diabetes. We related maternal vitamin D status in pregnancy to maternal and newborn glucose and insulin concentrations, and newborn size, in a South Indian population. Subjects/methods: Serum 25 hydroxy vitamin D (25(OH)D) concentrations, glucose tolerance, and plasma insulin, proinsulin and 32-33 split proinsulin concentrations were measured at 30 weeks gestation in 559 women who delivered at the Holdsworth Memorial Hospital, Mysore. The babies' anthropometry and cord plasma glucose, insulin and insulin precursor concentrations were measured. Results: 66% of women had hypovitaminosis D [25(OH)D concentrations <50 nmol/l] and 31% were below 28 nmol/l. There was seasonal variation in 25(OH)D concentrations (P<0.0001). There was no association between maternal 25(OH)D and gestational diabetes (incidence 7% in women with and without hypovitaminosis D). Maternal 25(OH)D concentrations were unrelated to newborn anthropometry or cord plasma variables. In mothers with hypovitaminosis D, higher 25(OH)D concentrations were associated with lower 30-minute glucose concentrations (p=0.03) and higher fasting proinsulin concentrations (p=0.04). Conclusions: Hypovitaminosis D at 30 weeks gestation is common in Mysore mothers. It is not associated with an increased risk of gestational diabetes, impaired fetal growth, or altered neonatal cord plasma insulin secretory profile. PMID:18285809

Validation of Reported Whole-Grain Intake from a Web-Based Dietary Record against Plasma Alkylresorcinol Concentrations in 8- to 11-Year-Olds Participating in a Randomized Controlled Trial.

PubMed

Biltoft-Jensen, Anja; Damsgaard, Camilla T; Andersen, Elisabeth W; Ygil, Karin H; Andersen, Rikke; Ege, Majken; Christensen, Tue; Thorsen, Anne-Vibeke; Tetens, Inge; Wu, Huaxing; Landberg, Rikard

2016-02-01

Whole-grain (WG) intake is important for human health, but accurate intake estimation is challenging. Use of a biomarker for WG intake provides a possible way to validate dietary assessment methods. Our aim was to validate WG intake from 2 diets reported by children, using plasma alkylresorcinol (AR) concentrations, and to investigate the 3-mo reproducibility of AR concentrations and reported WG intake. AR concentrations were analyzed in fasting blood plasma samples, and WG intake was estimated in a 7-d web-based diary by 750 participants aged 8-11 y in a 2 school meal × 3 mo crossover trial. Reported WG intake and plasma AR concentrations were compared when children ate their usual bread-based lunch (UBL) and when served a hot lunch meal (HLM). Correlations and cross-classification were used to rank subjects according to intake. The intraclass correlation coefficients (ICCs) between subjects' measurements at baseline and after the UBL were used to assess reproducibility. Correlations between reported WG wheat + rye intake and plasma AR were 0.40 and 0.37 (P < 0.001) for the UBL and the HLM diets, and 78% and 77% were classified in the same or adjacent quartiles for the UBL and HLM diets, respectively. The ICC over 3 mo was 0.47 (95% CI: 0.38, 0.55) for plasma total ARs and 0.64 (95% CI: 0.58, 0.70) for reported WG intake. Correlations were higher when using the AR C17:0 homolog as a biomarker, reflecting rye intake instead of plasma total ARs [UBL: r = 0.47; HLM: r = 0.43, P < 0.001; ICC = 0.51 (95% CI: 0.43, 0.59)]. Self-reported WG wheat + rye intake among children showed moderate correlations with plasma AR concentrations. Substantial intraindividual variation was found in WG intake and plasma AR concentrations. The AR homolog C17:0 may be used as a biomarker for WG intake when the WG intake primarily comes from rye as in the present study. This trial was registered at clinicaltrials.gov as NCT01457794. © 2016 American Society for Nutrition.

B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans.

PubMed

Majchrzak, D; Singer, I; Männer, M; Rust, P; Genser, D; Wagner, K-H; Elmadfa, I

2006-01-01

A vegetarian diet is considered to promote health and longevity and reduce the risk of cardiovascular diseases and cancer. However, a vegetarian diet may be deficient in some nutrients. Exclusion of animal products in vegetarian diets may affect the status of certain B-vitamins, and further cause the rise of plasma homocysteine concentration. The nutritional status of various B-vitamins (B(1), B(2), B(6), B(12), folic acid) and the concentration of homocysteine in blood plasma of omnivores (n = 40), vegetarians (n = 36) and vegans (n = 42) in Austria was evaluated. The evaluation was done using the functional parameters erythrocyte transketolase (ETK), glutathione reductase (EGR) and glutamic oxaloacetic transaminase (EGOT) activation coefficients. Enzyme activity was measured photometrically. The quantity of vitamins B(1), B(2) and B(6) in urine and the concentrations of vitamin B(6) and homocysteine in plasma were determined by HPLC methods with fluorescence detection. Plasma concentration of vitamin B(12) and folic acid were measured with radioimmunoassay. Most of the subjects showed a satisfying vitamin B(1) status. Vegans presented a significantly lower mean plasma vitamin B(12) concentration than omnivores and vegetarians and deficiency in 2.4% of the volunteers but the highest mean value of plasma folate among the investigated groups. A deficient status of folate was found in 18% of omnivores and in approximately 10% of vegans and vegetarians. The status of riboflavin is considered to be deficient in about 10% of omnivores and vegetarians and in over 30% of vegans. According to the activation coefficient of GOT, approximately one third of all subjects showed vitamin B(6) deficiency. Elevated homocysteine concentration in plasma was observed in 66% of the vegans and about 45-50% of the omnivores and vegetarians. Vegan subjects had significantly higher mean plasma homocysteine levels than omnivores. Thiamin and folate need not be a problem in a well-planned vegan diet. Vitamins B(12) and B(2) may need attention in the strict vegan diet, especially regarding elevated homocysteine levels in plasma. Pyridoxine status appeared to be independent of the diet. Copyright 2006 S. Karger AG, Basel.

Application of DBS sampling in combination with LC-MS/MS for pharmacokinetic evaluation of a compound with species-specific blood-to-plasma partitioning.

PubMed

Xu, Guifen; Chen, Jiyun S; Phadnis, Ruta; Huang, Tom; Uyeda, Craig; Soto, Marcus; Stouch, Brian; Wells, Mary C; James, Christopher A; Carlson, Timothy J

2012-08-01

Dried blood spot (DBS) sampling in combination with LC-MS/MS has been used increasingly in drug discovery for quantitative analysis to support pharmacokinetic (PK) studies. In this study, we assessed the effect of blood-to-plasma (B:P) partitioning on the bioanalytical performance and PK data acquired by DBS for a compound AMG-1 with species and concentration-dependent B:P ratio. B:P partitioning did not adversely affect bioanalytical performance of DBS for AMG-1. For rat, (B:P ratio of 0.63), PK profiles from DBS and plasma methods were comparable. For dog, concentration-dependence of B:P ratio was observed both in vivo and in vitro. Additional studies demonstrated concentration-dependence of the compound's unbound fraction in plasma, which may contribute to the concentration-dependence of the B:P ratio. DBS is a promising sampling technique for preclinical pharmacokinetic studies. For compounds with high B:P ratio, caution needs to be applied for data comparison and interpretation between matrices.

Aqueous Plasma Pharmacy: Preparation Methods, Chemistry, and Therapeutic Applications

PubMed Central

Joslin, Jessica M.; McCall, James R.; Bzdek, Justin P.; Johnson, Derek C.; Hybertson, Brooks M.

2017-01-01

Plasma pharmacy is a subset of the broader field of plasma medicine. Although not strictly defined, the term aqueous plasma pharmacy (APP) is used to refer to the generation and distribution of reactive plasma-generated species in an aqueous solution followed by subsequent administration for therapeutic benefits. APP attempts to harness the therapeutic effects of plasma-generated oxidant species within aqueous solution in various applications, such as disinfectant solutions, cell proliferation related to wound healing, and cancer treatment. The subsequent use of plasma-generated solutions in the APP approach facilitates the delivery of reactive plasma species to internal locations within the body. Although significant efforts in the field of plasma medicine have concentrated on employing direct plasma plume exposure to cells or tissues, here we focus specifically on plasma discharge in aqueous solution to render the solution biologically active for subsequent application. Methods of plasma discharge in solution are reviewed, along with aqueous plasma chemistry and the applications for APP. The future of the field also is discussed regarding necessary research efforts that will enable commercialization for clinical deployment. PMID:28428835

Determination of plasma concentrations of levofloxacin by high performance liquid chromatography for use at a multidrug-resistant tuberculosis hospital in Tanzania

PubMed Central

Mpagama, Stellah; Kisonga, Riziki; Lekule, Isaack; Liu, Jie; Heysell, Scott

2017-01-01

Therapeutic drug monitoring may improve multidrug-resistant tuberculosis (MDR-TB) treatment outcomes. Levofloxacin demonstrates significant individual pharmacokinetic variability. Thus, we sought to develop and validate a high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection for levofloxacin in patients on MDR-TB treatment. The HPLC-UV method is based on a solid phase extraction (SPE) and a direct injection into the HPLC system. The limit of quantification was 0.25 μg/mL, and the assay was linear over the concentration range of 0.25—15 μg/mL (y = 0.5668x—0.0603, R2 = 0.9992) for the determination of levofloxacin in plasma. The HPLC-UV methodology achieved excellent accuracy and reproducibility along a clinically meaningful range. The intra-assay RSD% of low, medium, and high quality control samples (QC) were 1.93, 2.44, and 1.90, respectively, while the inter-assay RSD% were 3.74, 5.65, and 3.30, respectively. The mean recovery was 96.84%. This method was then utilized to measure levofloxacin concentrations from patients’ plasma samples from a retrospective cohort of consecutive enrolled subjects treated for MDR-TB at the national TB hospital in Tanzania during 5/3/2013–8/31/2015. Plasma was collected at 2 hours after levofloxacin administration, the time of estimated peak concentration (eCmax) treatment. Forty-one MDR-TB patients had plasma available and 39 had traceable programmatic outcomes. Only 13 (32%) patients had any plasma concentration that reached the lower range of the expected literature derived Cmax with the median eCmax being 5.86 (3.33–9.08 μg/ml). Using Classification and Regression Tree analysis, an eCmax ≥7.55 μg/mL was identified as the threshold which best predicted cure. Analyzing this CART derived threshold on treatment outcome, the time to sputum culture conversion was 38.3 ± 22.7 days vs. 47.8 ± 26.5 days (p = 0.27) and a greater proportion were cured, in 10 out of 15 (66.7%) vs. 6 out of 18 (33.3%) (p = 0.06) respectively. Furthermore, one patient with an eCmax/minimum inhibitory concentration (MIC) of only 1.13 acquired extensively drug resistant (XDR)-TB while undergoing treatment. The individual variability of levofloxacin concentrations in MDR-TB patients from Tanzania supports further study of the application of onsite therapeutic drug monitoring and MIC testing. PMID:28141813

Determination of plasma concentrations of levofloxacin by high performance liquid chromatography for use at a multidrug-resistant tuberculosis hospital in Tanzania.

PubMed

Ebers, Andrew; Stroup, Suzanne; Mpagama, Stellah; Kisonga, Riziki; Lekule, Isaack; Liu, Jie; Heysell, Scott

2017-01-01

Therapeutic drug monitoring may improve multidrug-resistant tuberculosis (MDR-TB) treatment outcomes. Levofloxacin demonstrates significant individual pharmacokinetic variability. Thus, we sought to develop and validate a high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection for levofloxacin in patients on MDR-TB treatment. The HPLC-UV method is based on a solid phase extraction (SPE) and a direct injection into the HPLC system. The limit of quantification was 0.25 μg/mL, and the assay was linear over the concentration range of 0.25-15 μg/mL (y = 0.5668x-0.0603, R2 = 0.9992) for the determination of levofloxacin in plasma. The HPLC-UV methodology achieved excellent accuracy and reproducibility along a clinically meaningful range. The intra-assay RSD% of low, medium, and high quality control samples (QC) were 1.93, 2.44, and 1.90, respectively, while the inter-assay RSD% were 3.74, 5.65, and 3.30, respectively. The mean recovery was 96.84%. This method was then utilized to measure levofloxacin concentrations from patients' plasma samples from a retrospective cohort of consecutive enrolled subjects treated for MDR-TB at the national TB hospital in Tanzania during 5/3/2013-8/31/2015. Plasma was collected at 2 hours after levofloxacin administration, the time of estimated peak concentration (eCmax) treatment. Forty-one MDR-TB patients had plasma available and 39 had traceable programmatic outcomes. Only 13 (32%) patients had any plasma concentration that reached the lower range of the expected literature derived Cmax with the median eCmax being 5.86 (3.33-9.08 μg/ml). Using Classification and Regression Tree analysis, an eCmax ≥7.55 μg/mL was identified as the threshold which best predicted cure. Analyzing this CART derived threshold on treatment outcome, the time to sputum culture conversion was 38.3 ± 22.7 days vs. 47.8 ± 26.5 days (p = 0.27) and a greater proportion were cured, in 10 out of 15 (66.7%) vs. 6 out of 18 (33.3%) (p = 0.06) respectively. Furthermore, one patient with an eCmax/minimum inhibitory concentration (MIC) of only 1.13 acquired extensively drug resistant (XDR)-TB while undergoing treatment. The individual variability of levofloxacin concentrations in MDR-TB patients from Tanzania supports further study of the application of onsite therapeutic drug monitoring and MIC testing.

Determination of Sphingosine-1-Phosphate in Human Plasma Using Liquid Chromatography Coupled with Q-Tof Mass Spectrometry

PubMed Central

Egom, Emmanuel E.; Fitzgerald, Ross; Canning, Rebecca; Pharithi, Rebabonye B.; Murphy, Colin; Maher, Vincent

2017-01-01

Evidence suggests that high-density lipoprotein (HDL) components distinct from cholesterol, such as sphingosine-1-phosphate (S1P), may account for the anti-atherothrombotic effects attributed to this lipoprotein. The current method for the determination of plasma levels of S1P as well as levels associated with HDL particles is still cumbersome an assay method to be worldwide practical. Recently, a simplified protocol based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the sensitive and specific quantification of plasma levels of S1P with good accuracy has been reported. This work utilized a triple quadrupole (QqQ)-based LC-MS/MS system. Here we adapt that method for the determination of plasma levels of S1P using a quadrupole time of flight (Q-Tof) based LC-MS system. Calibration curves were linear in the range of 0.05 to 2 µM. The lower limit of quantification (LOQ) was 0.05 µM. The concentration of S1P in human plasma was determined to be 1 ± 0.09 µM (n = 6). The average accuracy over the stated range of the method was found to be 100 ± 5.9% with precision at the LOQ better than 10% when predicting the calibration standards. The concentration of plasma S1P in the prepared samples was stable for 24 h at room temperature. We have demonstrated the quantification of plasma S1P using Q-Tof based LC-MS with very good sensitivity, accuracy, and precision that can used for future studies in this field. PMID:28820460

Soluble TRAIL in Normal Pregnancy and Acute Pyelonephritis: a Potential Explanation for the Susceptibility of Pregnant Women to Microbial Products and Infection

PubMed Central

Chaemsaithong, Piya; Romero, Roberto; Korzeniewski, Steven J.; Schwartz, Alyse G.; Stampalija, Tamara; Dong, Zhong; Yeo, Lami; Hernandez-Andrade, Edgar; Hassan, Sonia S; Chaiworapongsa, Tinnakorn

2014-01-01

Objective Pregnancy is characterized by activation of the innate immune response demonstrated by phenotypic and metabolic changes in granulocytes and monocytes. This state of activation has been implicated in the pathophysiology of multiorgan dysfunction of pregnant women with acute viral or bacterial infection. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is one of the mediators responsible for neutrophil apoptosis. Gene deletion of TRAIL results in delayed neutrophil apoptosis and resolution of inflammation after the administration of bacterial endotoxin. The aim of this study was to determine if maternal plasma concentrations of the soluble form of TRAIL (sTRAIL) differ in women with uncomplicated pregnancy and those with acute pyelonephritis. Method A cross-sectional study was conducted to include women in the following groups: 1) non-pregnant (n=23); 2) uncomplicated pregnancies (n=93); and 3) pregnancies with acute pyelonephritis (n=23). Plasma concentrations of sTRAIL were determined by ELISA. Results 1) Women with uncomplicated pregnancies had a lower mean plasma sTRAIL concentration (pg/mL) than non-pregnant women (31.5 ± 10.1 vs. 53.3 ± 12.5; p < 0.001); 2) plasma sTRAIL concentrations did not change as a function of gestational age (Pearson correlation = −0.1; p=0.4); 3) the mean plasma sTRAIL concentration (pg/mL) was significantly lower in pregnant women with acute pyelonephritis than in those with uncomplicated pregnancies (20.5 ± 6.6 vs. 31.5 ± 10.1; p<0.001); and 4) among patients with acute pyelonephritis, patients with bacteremia had a significantly lower mean plasma concentration of sTRAIL (pg/mL) than those without bacteremia (15.1 ± 4.8 vs. 24.7 ± 4.6; p< 0.001). Conclusion Women with uncomplicated pregnancies are associated with a significantly lower mean maternal plasma concentration of sTRAIL than that observed in non-pregnant women. Moreover, a further decrease of plasma sTRAIL concentration was observed in pregnant women with acute pyelonephritis, and this could account, at least in part, for the exaggerated intravascular inflammatory response previously reported in pyelonephritis during pregnancy. PMID:23480056

FEV1 inversely correlates with metalloproteinases 1, 7, 9 and CRP in COPD by biomass smoke exposure

PubMed Central

2014-01-01

Background Matrix metalloproteinases (MMPs) and C-reactive protein (CRP) are involved in chronic obstructive pulmonary disease (COPD) pathogenesis. The aim of the present work was to determine plasma concentrations of MMPs and CRP in COPD associated to biomass combustion exposure (BE) and tobacco smoking (TS). Methods Pulmonary function tests, plasma levels of MMP-1, MMP-7, MMP-9, MMP-9/TIMP-1 and CRP were measured in COPD associated to BE (n = 40) and TS (n =40) patients, and healthy non-smoking (NS) healthy women (controls, n = 40). Results Plasma levels of MMP-1, MMP-7, MMP-9, and MMP-9/TIMP-1 and CRP were higher in BE and TS than in the NS healthy women (p <0.01). An inverse correlation between MMP-1, MMP-7, MMP-9, MMP-9/TIMP-1 and CRP plasma concentrations and FEV1 was observed. Conclusions Increase of MMPs and CRP plasma concentrations in BE suggests a systemic inflammatory phenomenon similar to that observed in COPD associated to tobacco smoking, which may also play a role in COPD pathogenesis. PMID:24980707

New approach to the determination phosphorothioate oligonucleotides by ultra high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry.

PubMed

Studzińska, Sylwia; Mounicou, Sandra; Szpunar, Joanna; Łobiński, Ryszard; Buszewski, Bogusław

2015-01-15

This text presents a novel method for the separation and detection of phosphorothioate oligonucleotides with the use of ion pair ultra high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry The research showed that hexafluoroisopropanol/triethylamine based mobile phases may be successfully used when liquid chromatography is coupled with such elemental detection. However, the concentration of both HFIP and TEA influences the final result. The lower concentration of HFIP, the lower the background in ICP-MS and the greater the sensitivity. The method applied for the analysis of serum samples was based on high resolution inductively coupled plasma mass spectrometry. Utilization of this method allows determination of fifty times lower quantity of phosphorothioate oligonucleotides than in the case of quadrupole mass analyzer. Monitoring of (31)P may be used to quantify these compounds at the level of 80 μg L(-1), while simultaneous determination of sulfur is very useful for qualitative analysis. Moreover, the results presented in this paper demonstrate the practical applicability of coupling LC with ICP-MS in determining phosphorothioate oligonucleotides and their metabolites in serum within 7 min with a very good sensitivity. The method was linear in the concentration range between 0.2 and 3 mg L(-1). The limit of detection was in the range of 0.07 and 0.13 mg L(-1). Accuracy varied with concentration, but was in the range of 3%. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and Validation of highly Sensitive Stability Indicating Spectrofluorimetric Method for Determination of Amlodipine in Pharmaceutical Preparations and Human Plasma.

PubMed

Mohamed, Abdel-Maaboud I; Omar, Mahmoud A; Hammad, Mohamed A; Mohamed, Abobakr A

2016-11-01

A highly sensitive and simple spectrofluorimetric method was developed for the determination of Amlodipine besylate (AML) in its pharmaceutical formulations and spiked human plasma. The proposed method is based on the investigation of the fluorescence spectral behaviour of AML in Tween-80 micellar system. In aqueous solution, the fluorescence intensity of AML was greatly enhanced (160 %) in the presence of Tween-80. The fluorescence intensity was measured at 427 nm after excitation at 385 nm. The fluorescence-concentration plot was rectilinear over the concentration range 0.1-4.0 μg/ml, with lower detection limit of 0.03 μg/ml. The suggested method was successfully applied for the analysis of AML in its commercial tablets alone or in combination with either Atorvastatin or Valsartan. The application of the proposed method was extended to the assay of AML in spiked human plasma and stability studies of AML after exposure to different forced degradation conditions, such as acidic, alkaline, photo- and oxidative conditions, according to ICH guidelines. The results were statistically compared to those obtained by comparison methods and were found to be in good agreement.

A modified HPLC method improves the simultaneous determination of plasma kynurenine and tryptophan concentrations in patients following maintenance hemodialysis

PubMed Central

XIAO, CHENGGEN; CHEN, YUANHAN; LIANG, XINLING; XIE, ZHEN; ZHANG, MIN; LI, RUIZHAO; LI, ZHILIAN; FU, XIA; YU, XIYONG; SHI, WEI

2014-01-01

The ratio between plasma kynurenine (Kyn) and tryptophan (Trp) serves as a marker of indoleamine 2,3-dioxygenase, a critical immunomodulatory molecule. Simultaneous detection of the two markers may be performed using high-pressure liquid chromatography (HPLC). However, for uremic patients, the conventional detection method may be affected by a range of accumulated toxins. The current study aimed to establish a method for the simultaneous measurement of Kyn and Trp in patients following maintenance hemodialysis via HPLC-ultraviolet detection. The procedure involved the use of a SinoChrom ODS-BP C18 column (4.6×150 mm; inner diameter, 4.5 μm) and a mobile phase of 15 mmol/l sodium acetate acetic acid solution (containing 5% acetonitrile, pH 4.8). The modified method was verified using plasma samples from 10 healthy controls and 91 maintenance hemodialysis patients. The results demonstrated that the modified method was successful in simultaneously detecting the concentrations of Trp and Kyn in the healthy controls and maintenance hemodialysis patients. The method is simple, fast, accurate and suitable for clinical and research purposes in maintenance hemodialysis patients. PMID:24669249

Development and validation of a high-performance liquid chromatography method for determination of cefquinome concentrations in sheep plasma and its application to pharmacokinetic studies.

PubMed

Uney, Kamil; Altan, Feray; Elmas, Muammer

2011-02-01

Cefquinome has a broad spectrum of antibacterial activity and was developed especially for use in animals. A simple and sensitive high-performance liquid chromatography (HPLC) method with UV-visible detection for quantification of cefquinome concentrations in sheep plasma was developed and validated. Separation of cefquinome from plasma components was achieved on a Phenomenex Gemini C(18) column (250 mm by 4.6 mm; internal diameter [i.d.], 5 μm). The mobile phase consisted of acetonitrile and 0.1% trifluoroacetic acid in water and was delivered at a rate of 0.9 ml/min. A simple and rapid sample preparation involved the addition of methanol to 200 μl of plasma to precipitate plasma proteins followed by direct injection of 50 μl of supernatant into the high-performance liquid chromatography system. The linearity range of the proposed method was 0.02 to 12 μg/ml. The intraday and interday coefficients of variation obtained from cefquinome were less than 5%, and biases ranged from -3.76% to 1.24%. Mean recovery based on low-, medium-, and high-quality control standards ranged between 92.0 and 93.9%. Plasma samples were found to be stable in various storage conditions (freeze-thaw, postpreparative, short-term, and long-term stability). The method described was found to be readily available, practicable, cheap, rapid, sensitive, precise, and accurate. It was successfully applied to the study of the pharmacokinetics of cefquinome in sheep. This method can be very useful and an alternate to performing pharmacokinetic studies in the determination of cefquinome for clinical use.

[Direct and indirect ion selective electrodes methods: the differences specified through a case of Waldenström's macroglobulinemia].

PubMed

Zelmat, Mohamed Sofiane

2015-01-01

Direct and indirect ion selective electrodes (ISEs) are two methods commonly used in biochemistry laboratories in order to measure the electrolytes such as sodium. In the clinical practice, it's the sodium concentration in plasma water -measured by direct ISE- which is important to consider as it is responsible of water movements between the liquid compartments. Knowing the difference between the two methods is important because there are situations leading to conflicting results between direct and indirect ISE, especially with sodium and inappropriate therapeutic decisions could be taken if the clinician is not aware of this difference. The increase and the decrease in plasma water volume are the situations that distort the results of the indirect ISE because this method, after a dilution step, does not take into account the real percentage of plasma water of the patient in the determination of the concentrations (leading for sodium to pseudohyponatremia, pseudonormonatremia or pseudohypernatremia). In the direct ISE, the sample is not diluted and the results are correct even if the volume of plasma water is modified. This article specifies the differences between the two techniques through a case of Waldenström's macroglobulinemia and proposes a course of action to follow for both of the biologist and the clinician.

Validation of a method for the determination of zolpidem in human plasma using LC with fluorescence detection.

PubMed

Ring, P R; Bostick, J M

2000-04-01

A sensitive and selective high-performance liquid chromatography (HPLC) method was developed for the determination of zolpidem in human plasma. Zolpidem and the internal standard (trazodone) were extracted from human plasma that had been made basic. The basic sample was loaded onto a conditioned Bond Elut C18 cartridge, rinsed with water and eluted with methanol. Forty microliters were then injected onto the LC system. Separation was achieved on a C18 column (150 x 4.6 mm, 5 microm) with a mobile phase composed of acetonitrile:50 mM potassium phosphate monobasic at pH 6.0 (4:6, v/v). Detection was by fluorescence, with excitation at 254 nm and emission at 400 nm. The retention times of zolpidem and internal standard were approximately 4.7 and 5.3 min, respectively. The LC run time was 8 min. The assay was linear in concentration range 1-400 ng/ml for zolpidem in human plasma. The analysis of quality control samples for zolpidem (3, 30, and 300 ng/ml) demonstrated excellent precision with relative standard deviations (RSD) of 3.7, 4.6, and 3.0%, respectively (n = 18). The method was accurate with all intraday (n = 6) and overall (n = 18) mean concentrations within 5.8% from nominal at all quality control sample concentrations. This method was also performed using a Gilson Aspec XL automated sample processor and autoinjector. The samples were manually fortified with internal standard and made basic. The aspec then performed the solid phase extraction and made injections of the samples onto the LC system. Using the automated procedure for analysis, quality control samples for zolpidem (3, 30, and 300 ng/ml) demonstrated acceptable precision with RSD values of 9.0, 4.9, and 5.1%, respectively (n = 12). The method was accurate with all intracurve (n = 4) and overall (n = 12) mean values being less than 10.8% from nominal at all quality control sample concentrations.

ERYTHROPOIETIC FACTOR PURIFICATION

DOEpatents

White, W.F.; Schlueter, R.J.

1962-05-01

A method is given for purifying and concentrating the blood plasma erythropoietic factor. Anemic sheep plasma is contacted three times successively with ion exchange resins: an anion exchange resin, a cation exchange resin at a pH of about 5, and a cation exchange resin at a pH of about 6. (AEC)

Fabrication of silicon-on-diamond substrate with an ultrathin SiO2 bonding layer

NASA Astrophysics Data System (ADS)

Nagata, Masahiro; Shirahama, Ryouya; Duangchan, Sethavut; Baba, Akiyoshi

2018-06-01

We proposed and demonstrated a sputter etching method to prepare both a flat surface (root-mean-square surface roughness of approximately 0.2–0.3 nm) and an ultrathin SiO2 bonding layer at an accuracy of approximately 5 nm in thickness to fabricate a silicon-on-diamond substrate (SOD). We also investigated a plasma activation method on a SiO2 surface using various gases. We found that O2 plasma activation is more suitable for the bonding between SiO2 and Si than N2 or Ar plasma activation. We speculate that the concentration of hydroxyl groups on the SiO2 surface was increased by O2 plasma activation. We fabricated the SOD substrate with an ultrathin (15 nm in thickness) SiO2 bonding layer using the sputter etching and O2 plasma activation methods.

Antioxidant capacity of human blood plasma and human urine: simultaneous evaluation of the ORAC index and ascorbic acid concentration employing pyrogallol red as probe.

PubMed

Torres, P; Galleguillos, P; Lissi, E; López-Alarcón, C

2008-10-15

The oxygen radical absorbance capacity (ORAC) methodology has been employed to estimate the antioxidant capacity of human blood plasma and human urine using pyrogallol red (ORAC-PGR) as target molecule. Uric acid, reduced glutathione, human serum albumin, and ascorbic acid (ASC) inhibited the consumption of pyrogallol red, but only ASC generated an induction time. Human blood plasma and human urine protected efficiently pyrogallol red. In these assays, both biological fluids generated neat induction times that were removed by ascorbate oxidase. From these results, ORAC-PGR method could be proposed as a simple alternative to evaluate an ORAC index and, simultaneously, to estimate the concentration of ascorbic acid in human blood plasma or human urine.

Utility of Hantzsch reaction for development of highly sensitive spectrofluorimetric method for determination of alfuzosin and terazosin in bulk, dosage forms and human plasma.

PubMed

Hammad, Mohamed A; Omar, Mahmoud A; Salman, Baher I

2017-09-01

A highly sensitive, cheap, simple and accurate spectrofluorimetric method has been developed and validated for the determination of alfuzosin hydrochloride and terazosin hydrochloride in their pharmaceutical dosage forms and in human plasma. The developed method is based on the reaction of the primary amine moiety in the studied drugs with acetylacetone and formaldehyde according to the Hantzsch reaction, producing yellow fluorescent products that can be measured spectrofluorimetrically at 480 nm after excitation at 415 nm. Different experimental parameters affecting the development and stability of the reaction products were carefully studied and optimized. The fluorescence-concentration plots of alfuzosin and terazosin were rectilinear over a concentration range of 70-900 ng ml -1 , with quantitation limits 27.1 and 32.2 ng ml -1 for alfuzosin and terazosin, respectively. The proposed method was validated according to ICH guidelines and successfully applied to the analysis of the investigated drugs in dosage forms, content uniformity test and spiked human plasma with high accuracy. Copyright © 2017 John Wiley & Sons, Ltd.

Beneficial Effects of Early Enteral Nutrition After Major Rectal Surgery: A Possible Role for Conditionally Essential Amino Acids? Results of a Randomized Clinical Trial.

PubMed

van Barneveld, Kevin W Y; Smeets, Boudewijn J J; Heesakkers, Fanny F B M; Bosmans, Joanna W A M; Luyer, Misha D; Wasowicz, Dareczka; Bakker, Jaap A; Roos, Arnout N; Rutten, Harm J T; Bouvy, Nicole D; Boelens, Petra G

2016-06-01

To investigate direct postoperative outcome and plasma amino acid concentrations in a study comparing early enteral nutrition versus early parenteral nutrition after major rectal surgery. Previously, it was shown that a low plasma glutamine concentration represents poor prognosis in ICU patients. A preplanned substudy of a previous prospective, randomized, open-label, single-centre study, comparing early enteral nutrition versus early parenteral nutrition in patients at high risk of postoperative ileus after surgery for locally advanced or locally recurrent rectal cancer. Early enteral nutrition reduced postoperative ileus, anastomotic leakage, and hospital stay. Tertiary referral centre for locally advanced and recurrent rectal cancer. A total of 123 patients with locally advanced or recurrent rectal carcinoma requiring major rectal surgery. Patients were randomized (ALEA web-based external randomization) preoperatively into two groups: early enteral nutrition (early enteral nutrition, intervention) by nasojejunal tube (n = 61) or early parenteral nutrition (early parenteral nutrition, control) by jugular vein catheter (n = 62). Eight hours after the surgical procedure artificial nutrition was started in hemodynamically stable patients, stimulating oral intake in both groups. Blood samples were collected to measure plasma glutamine, citrulline, and arginine concentrations using a validated ultra performance liquid chromatography-tandem mass spectrometric method. Baseline concentrations were comparable for both groups. Directly after rectal surgery, a decrease in plasma amino acids was observed. Plasma glutamine concentrations were higher in the parenteral group than in the enteral group on postoperative day 1 (p = 0.027) and day 5 (p = 0.008). Arginine concentrations were also significantly increased in the parenteral group at day 1 (p < 0.001) and day 5 (p = 0.001). Lower plasma glutamine and arginine concentrations were measured in the enteral group, whereas a better clinical outcome was observed. We conclude that plasma amino acids do not provide a causal explanation for the observed beneficial effects of early enteral feeding after major rectal surgery.

Identification of a Hemolysis Threshold That Increases Plasma and Serum Zinc Concentration.

PubMed

Killilea, David W; Rohner, Fabian; Ghosh, Shibani; Otoo, Gloria E; Smith, Lauren; Siekmann, Jonathan H; King, Janet C

2017-06-01

Background: Plasma or serum zinc concentration (PZC or SZC) is the primary measure of zinc status, but accurate sampling requires controlling for hemolysis to prevent leakage of zinc from erythrocytes. It is not established how much hemolysis can occur without changing PZC/SZC concentrations. Objective: This study determines a guideline for the level of hemolysis that can significantly elevate PZC/SZC. Methods: The effect of hemolysis on PZC/SZC was estimated by using standard hematologic variables and mineral content. The calculated hemolysis threshold was then compared with results from an in vitro study and a population survey. Hemolysis was assessed by hemoglobin and iron concentrations, direct spectrophotometry, and visual assessment of the plasma or serum. Zinc and iron concentrations were determined by inductively coupled plasma spectrometry. Results: A 5% increase in PZC/SZC was calculated to result from the lysis of 1.15% of the erythrocytes in whole blood, corresponding to ∼1 g hemoglobin/L added into the plasma or serum. Similarly, the addition of simulated hemolysate to control plasma in vitro caused a 5% increase in PZC when hemoglobin concentrations reached 1.18 ± 0.10 g/L. In addition, serum samples from a population nutritional survey were scored for hemolysis and analyzed for changes in SZC; samples with hemolysis in the range of 1-2.5 g hemoglobin/L showed an estimated increase in SZC of 6% compared with nonhemolyzed samples. Each approach indicated that a 5% increase in PZC/SZC occurs at ∼1 g hemoglobin/L in plasma or serum. This concentration of hemoglobin can be readily identified directly by chemical hemoglobin assays or indirectly by direct spectrophotometry or matching to a color scale. Conclusions: A threshold of 1 g hemoglobin/L is recommended for PZC/SZC measurements to avoid increases in zinc caused by hemolysis. The use of this threshold may improve zinc assessment for monitoring zinc status and nutritional interventions.

Identification of a Hemolysis Threshold That Increases Plasma and Serum Zinc Concentration123

PubMed Central

Otoo, Gloria E; Smith, Lauren; Siekmann, Jonathan H

2017-01-01

Background: Plasma or serum zinc concentration (PZC or SZC) is the primary measure of zinc status, but accurate sampling requires controlling for hemolysis to prevent leakage of zinc from erythrocytes. It is not established how much hemolysis can occur without changing PZC/SZC concentrations. Objective: This study determines a guideline for the level of hemolysis that can significantly elevate PZC/SZC. Methods: The effect of hemolysis on PZC/SZC was estimated by using standard hematologic variables and mineral content. The calculated hemolysis threshold was then compared with results from an in vitro study and a population survey. Hemolysis was assessed by hemoglobin and iron concentrations, direct spectrophotometry, and visual assessment of the plasma or serum. Zinc and iron concentrations were determined by inductively coupled plasma spectrometry. Results: A 5% increase in PZC/SZC was calculated to result from the lysis of 1.15% of the erythrocytes in whole blood, corresponding to ∼1 g hemoglobin/L added into the plasma or serum. Similarly, the addition of simulated hemolysate to control plasma in vitro caused a 5% increase in PZC when hemoglobin concentrations reached 1.18 ± 0.10 g/L. In addition, serum samples from a population nutritional survey were scored for hemolysis and analyzed for changes in SZC; samples with hemolysis in the range of 1–2.5 g hemoglobin/L showed an estimated increase in SZC of 6% compared with nonhemolyzed samples. Each approach indicated that a 5% increase in PZC/SZC occurs at ∼1 g hemoglobin/L in plasma or serum. This concentration of hemoglobin can be readily identified directly by chemical hemoglobin assays or indirectly by direct spectrophotometry or matching to a color scale. Conclusions: A threshold of 1 g hemoglobin/L is recommended for PZC/SZC measurements to avoid increases in zinc caused by hemolysis. The use of this threshold may improve zinc assessment for monitoring zinc status and nutritional interventions. PMID:28490675

Venous blood provides lower GLP-1 concentrations than arterialised blood in the postprandial, but not fasted state: Consequences of sampling methods.

PubMed

Chen, Yung-Chih; Edinburgh, Robert M; Hengist, Aaron; Smith, Harry A; Walhin, Jean-Philippe; Betts, James A; Thompson, Dylan; Gonzalez, Javier T

2018-06-27

What is the central question of this study? Glucagon-like peptide-1 (GLP-1) is an important obesity/diabetes target, with effects dependent on circulating GLP-1 concentrations. Peripheral tissues extract GLP-1, therefore sampling venous versus arterialised blood may provide different GLP-1 concentrations. This study examined whether arterialisation alters GLP-1 concentrations during fasting and feeding. What is the main finding and its importance? This study demonstrates that venous blood provides lower postprandial, but not fasting, GLP-1 concentrations versus arterialised blood. Therefore, when accurate assessment of postprandial peripheral availability of GLP-1 is required, blood sampling methods should be carefully considered, clearly reported, and arterialisation is recommended. Glucagon-like peptide-1 (GLP-1) displays concentration-dependent effects on metabolism, appetite and angiogenesis, so accurate determination of circulating GLP-1 concentrations is important. This study compared GLP-1 concentrations in venous versus arterialised blood under both fasted and fed conditions. Venous and arterialised blood samples were simultaneously drawn from ten, young, healthy men before, and 30, 60 and 120 min after, ingestion of 75 g glucose. Plasma GLP-1 concentrations increased in response to glucose ingestion (time effect: p < 0.01) and to a lesser extend in venous versus arterialised plasma (time x arterialisation interaction: p < 0.01). Accordingly, the plasma incremental area under the curve was lower in venous versus arterialised plasma (974 ± 88 versus 1214 ± 115 pmol·L x 120 min -1 , respectively, p = 0.049). In the postprandial state, there was a positive relationship between arterialised GLP-1 concentrations and the venous-arterialised difference in GLP-1 concentrations (r 2  = 0.51; p < 0.01). Both arterialised and venous peak GLP-1 concentrations showed positive relationships with peak arterialised insulin concentrations (both r 2  > 0.6, p < 0.01). Venous sampling results in lower concentrations of GLP-1 in the postprandial, but not the fasted state compared to arterialised blood. This absolute difference is biologically meaningful and is magnified when GLP-1 availability is high. Therefore, sampling from arterialised blood may provide a better chance of detecting small differences in postprandial GLP-1 availability with interventions and if absolute GLP-1 concentrations are of interest, the blood sampling method should be carefully considered and clearly reported. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The influence of Actinobacillus pleuropneumoniae infection on tulathromycin pharmacokinetics and lung tissue disposition in pigs.

PubMed

Gajda, A; Bladek, T; Jablonski, A; Posyniak, A

2016-04-01

A tulathromycin concentration and pharmacokinetic parameters in plasma and lung tissue from healthy pigs and Actinobacillus pleuropneumoniae (App)-infected pigs were compared. Tulathromycin was administered intramuscularly (i.m.) to all pigs at a single dose of 2.5 mg/kg. Blood and lung tissue samples were collected during 33 days postdrug application. Tulathromycin concentration in plasma and lung was determined by high-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. The mean maximum plasma concentration (Cmax ) in healthy pigs was 586 ± 71 ng/mL, reached by 0.5 h, while the mean value for Cmax of tulathromycin in infected pigs was 386 ± 97 ng/mL after 0.5 h. The mean maximum tulathromycin concentration in lung of healthy group was calculated as 3412 ± 748 ng/g, detected at 12 h, while in pigs with App, the highest concentration in lung was 3337 ± 937 ng/g, determined at 48 h postdosing. The higher plasma and lung concentrations in pigs with no pulmonary inflammation were observed at the first time points sampling after tulathromycin administration, but slower elimination with elimination half-life t1/2el  = 126 h in plasma and t1/2el  = 165 h in lung, as well as longer drug persistent in infected pigs, was found. © 2015 John Wiley & Sons Ltd.

Bovine and porcine heparins: different drugs with similar effects on human haemodialysis

PubMed Central

2013-01-01

Background Heparins from porcine and bovine intestinal mucosa differ in their structure and also in their effects on coagulation, thrombosis and bleeding. However, they are used as undistinguishable drugs. Methods We compared bovine and porcine intestinal heparin administered to patients undergoing a particular protocol of haemodialysis. We compared plasma concentrations of these two drugs and also evaluated how they affect patients and the dialyzer used. Results Compared with porcine heparin, bovine heparin achieved only 76% of the maximum plasma concentration as IU mL-1. This observation is consistent with the activities observed in the respective pharmaceutical preparations. When the plasma concentrations were expressed on weight basis, bovine heparin achieved a maximum concentration 1.5 fold higher than porcine heparin. The reduced anticoagulant activity and higher concentration, on weight basis, achieved in the plasma of patients under dialysis using bovine instead of porcine heparin did not affect significantly the patients or the dialyzer used. The heparin dose is still in a range, which confers security and safety to the patients. Discussion Despite no apparent difference between bovine and porcine intestinal heparins in the haemodialysis practice, these two types of heparins should be used as distinct drugs due to their differences in structure and biological effects. Conclusions The reduced anticoagulant activity achieved in the plasma of patients under dialysis using bovine instead of porcine heparin did not affect significantly the patients or the dialyzer. PMID:23763719

[Increased myelopepoxidase activity is a risk factor for ishemic heart disease in patients with diabetes mellitus].

PubMed

Gorudko, I V; Kostevich, A V; Sokolov, A V; Konstatinova, E É; Tsapaeva, N L; Mironova, E V; Zakharova, E T; Vasil'ev, V B; Cherenkevich, S N; Panasenko, A M

2012-01-01

Using previously developed spectro-photonmetrical method (Bioorg. Khim. 2009. V. 35. pp. 629-639), a significant increase of myeloperoxidase (MPO) activity was found in blood plasma of patients with type 2 diabetes mellitus (DM2) without of cardiovascular complications, as well as with ischemic heart disease (IHD). Plasma MPO concentration measured by an enzyme-linked immunosorbent assay was significantly higher only in blood plasma of patient with DM2 and IHD. A direct and significant correlation between MPO activity and MPO concentration was observed only in blood plasma samples from healthy donors. Increased MPO activity did not correlate with MPO concentration in blood plasma of patients with DM2 and DM2 with IHD. Taken together, these results highlight the necessity for studying of the MPO role in the development of pathological processes to determine both the amount of enzyme and its peroxidase activity in the blood. The proposed approach gives comprehensive information about the relationship between MPO activity and MPO concentration in patient blood. Since the high concentration of MPO is a diagnostically significant parameter in the prediction of endothelial dysfunction and cardiovascular disease development, the obtained results evidence the contribution of MPO-dependent reactions in cardiovascular complications associated with diabetes. MPO activity may serve as an additional diagnostic criterion for determination of risk of IHD in DM patients.

The male genital tract is not a pharmacological sanctuary from efavirenz.

PubMed

Avery, L B; Bakshi, R P; Cao, Y J; Hendrix, C W

2011-07-01

Many antiretroviral (ARV) drugs have large blood plasma-to-seminal plasma (BP/SP) concentration ratios. Concern exists that these drugs do not adequately penetrate the male genital tract (MGT), resulting in the MGT becoming a "pharmacological sanctuary" from these agents, with ineffective MGT concentrations despite effective blood concentrations. Efavirenz (EFV) is the most highly protein-bound ARV drug, with >99% binding in blood plasma and the largest BP/SP total EFV concentration ratio, reportedly ranging from 11 to 33. To evaluate protein binding as an explanation for the differences between the drug concentrations in blood and semen, we developed a novel ultrafiltration method, corrected for the duration of centrifugation, to measure protein binding in the two matrices. In six subjects, protein-free EFV concentrations were the same in blood and semen; the median (interquartile range (IQR)) protein-free EFV SP/BP ratio was 1.21 (0.99-1.35); EFV protein binding was 99.82% (99.79-99.86) in BP and 95.26% (93.24-96.67) in SP. This shows that the MGT is not a sanctuary from EFV.

Development, validation and application of a micro-liquid chromatography-tandem mass spectrometry based method for simultaneous quantification of selected protein biomarkers of endothelial dysfunction in murine plasma.

PubMed

Suraj, Joanna; Kurpińska, Anna; Olkowicz, Mariola; Niedzielska-Andres, Ewa; Smolik, Magdalena; Zakrzewska, Agnieszka; Jasztal, Agnieszka; Sitek, Barbara; Chlopicki, Stefan; Walczak, Maria

2018-02-05

The objective of this study was to develop and validate the method based on micro-liquid chromatography-tandem mass spectrometry (microLC/MS-MRM) for simultaneous determination of adiponectin (ADN), von Willebrand factor (vWF), soluble form of vascular cell adhesion molecule 1 (sVCAM-1), soluble form of intercellular adhesion molecule 1 (sICAM-1) and syndecan-1 (SDC-1) in mouse plasma. The calibration range was established from 2.5pmol/mL to 5000pmol/mL for ADN; 5pmol/mL to 5000pmol/mL for vWF; 0.375pmol/mL to 250pmol/mL for sVCAM-1 and sICAM-1; and 0.25pmol/mL to 250pmol/mL for SDC-1. The method was applied to measure the plasma concentration of selected proteins in mice fed high-fat diet (HFD), and revealed the pro-thrombotic status by increased concentration of vWF (1.31±0.17 nmol/mL (Control) vs 1.98±0.09 nmol/mL (HFD), p <0.05) and the dysregulation of adipose tissue metabolism by decreased concentration of ADN (0.62±0.08 nmol/mL (Control) vs 0.37±0.06 nmol/mL (HFD), p <0.05). In conclusion, the microLC/MS-MRM-based method allows for reliable measurements of selected protein biomarkers of endothelial dysfunction in mouse plasma. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrasound-assisted combined with nano-sized molecularly imprinted polymer for selective extraction and pre-concentration of amitriptyline in human plasma with gas chromatography-flame detection.

PubMed

Khanahmadzadeh, Salah; Tarigh, Ahmad

2014-12-01

A new process was developed for the selective extraction and pre-concentration of amitriptyline (AT) from human plasma using nano-sized molecularly imprinted polymer (MIP) with ultrasound-assisted extraction (UAE). The nano-sized AT imprinted polymer particles were synthesized using suspension polymerization in silicon oil and characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope (SEM) methods. With the application of optimized values, linearity values in the ranges of 20-200μgmL(-1) and 35-200μgmL(-1) were obtained for AT with the correlation of determination values (r(2)) 0.998 and 0.995 in water and plasma, respectively. The limits of detections (S/N=3) for AT were found to be 0.7 and 1.2μgmL(-1) in water and plasma, respectively. The enrichment factors of AT in water and plasma were 52 and 40, respectively. The inter-day precisions (%) were in the range of 5.8-9.2%. Relative recovery rates ranged from 82.4% to 92.3%. The method was successfully applied to determine AT in the human plasma samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Prediction of human pharmacokinetics using physiologically based modeling: a retrospective analysis of 26 clinically tested drugs.

PubMed

De Buck, Stefan S; Sinha, Vikash K; Fenu, Luca A; Nijsen, Marjoleen J; Mackie, Claire E; Gilissen, Ron A H J

2007-10-01

The aim of this study was to evaluate different physiologically based modeling strategies for the prediction of human pharmacokinetics. Plasma profiles after intravenous and oral dosing were simulated for 26 clinically tested drugs. Two mechanism-based predictions of human tissue-to-plasma partitioning (P(tp)) from physicochemical input (method Vd1) were evaluated for their ability to describe human volume of distribution at steady state (V(ss)). This method was compared with a strategy that combined predicted and experimentally determined in vivo rat P(tp) data (method Vd2). Best V(ss) predictions were obtained using method Vd2, providing that rat P(tp) input was corrected for interspecies differences in plasma protein binding (84% within 2-fold). V(ss) predictions from physicochemical input alone were poor (32% within 2-fold). Total body clearance (CL) was predicted as the sum of scaled rat renal clearance and hepatic clearance projected from in vitro metabolism data. Best CL predictions were obtained by disregarding both blood and microsomal or hepatocyte binding (method CL2, 74% within 2-fold), whereas strong bias was seen using both blood and microsomal or hepatocyte binding (method CL1, 53% within 2-fold). The physiologically based pharmacokinetics (PBPK) model, which combined methods Vd2 and CL2 yielded the most accurate predictions of in vivo terminal half-life (69% within 2-fold). The Gastroplus advanced compartmental absorption and transit model was used to construct an absorption-disposition model and provided accurate predictions of area under the plasma concentration-time profile, oral apparent volume of distribution, and maximum plasma concentration after oral dosing, with 74%, 70%, and 65% within 2-fold, respectively. This evaluation demonstrates that PBPK models can lead to reasonable predictions of human pharmacokinetics.

Pharmacokinetics of Intraperitoneal Cefalothin and Cefazolin in Patients Being Treated for Peritoneal Dialysis-Associated Peritonitis.

PubMed

Roberts, Darren M; Ranganathan, Dwarakanathan; Wallis, Steven C; Varghese, Julie M; Kark, Adrian; Lipman, Jeffrey; Roberts, Jason A

2016-01-01

♦ The standard treatment of peritoneal dialysis (PD)-associated peritonitis (PD-peritonitis) is intraperitoneal (IP) administration of antibiotics. Only limited data on the pharmacokinetics and appropriateness of contemporary dose recommendations of IP cefalothin and cefazolin exist. The aim of this study was to describe the pharmacokinetics of IP cefalothin and cefazolin in patients treated for PD-peritonitis. ♦ As per international guidelines, IP cefalothin or cefazolin 15 mg/kg once daily was dosed with gentamicin in a 6-hour dwell to patients with PD-peritonitis during routine care. Serial plasma and PD effluent samples were collected over the first 24 hours of therapy. Antibiotic concentrations were quantified using a validated chromatographic method with pharmacokinetic analysis performed using a non-compartmental approach. ♦ Nineteen patients were included (cefalothin n = 8, cefazolin n = 11). The median bioavailability for both antibiotics exceeded 92%, but other pharmacokinetic parameters varied markedly between antibiotics. Both antibiotics achieved high PD effluent concentrations throughout the antibiotic dwell. Cefazolin had a smaller volume of distribution compared with cefalothin (14 vs 40 L, p = 0.003). The median trough total plasma antibiotic concentration for cefazolin and cefalothin during the dwell differed (plasma 56 vs 13 mg/L, p < 0.0001) despite a similar concentration in PD effluent (37 vs 38 mg/L, p = 0.58). Lower antibiotic concentrations were noted during PD dwells not containing antibiotic, particularly cefalothin, which was frequently undetectable in plasma and PD effluent. The median duration that the unbound antibiotic concentration was above the minimum inhibitory concentration (MIC) was approximately 13% (plasma) and 25% (IP) for cefalothin, and 100% (plasma and IP) for cefazolin, of the dosing interval. ♦ When IP cefalothin or cefazolin is allowed to dwell for 6 hours, sufficient PD effluent concentrations are present for common pathogens during this time. However, with once-daily IP dosing, in contrast to cefazolin, there is a risk of subtherapeutic plasma and PD effluent cefalothin concentrations, so more frequent dosing may be required. Copyright © 2016 International Society for Peritoneal Dialysis.

Establishing human heart chromium, cobalt and vanadium concentrations by inductively coupled plasma mass spectrometry.

PubMed

Day, Patrick L; Eckdahl, Steven J; Maleszewski, Joseph J; Wright, Thomas C; Murray, David L

2017-05-01

Chromium, cobalt, and vanadium are used in metallic joint prosthesis. Case studies have associated elevated heart tissue cobalt concentrations with myocardial injury. To document the long term heart metal ion concentrations, a validated inductively coupled plasma mass spectroscopy (ICP-MS) method was needed. The method utilized a closed-vessel microwave digestion system to digest the samples. An ICP-MS method utilizing Universal Cell Technology was used to determine our target analyte concentrations. Accuracy was verified using reference materials. Precision, sensitivity, recovery and linearity studies were performed. This method was used to establish a reference range for a non-implant containing cohort of 80 autopsy human heart tissues RESULTS: This method demonstrated an analytic measurement range of 0.5-100ng/mL for each element. Accuracy was within ±10% of target value for each element. Within-run precision for each element was below 20% CV. The chromium, vanadium and cobalt concentrations (mean±SD) were 0.1523±0.2157μg/g, 0.0094±0.0211μg/g and 0.1039±0.1305μg/g respectively in 80 non-implant containing human heart tissue samples. This method provides acceptable recovery of the chromium, cobalt and vanadium in heart tissue; allowing assessment of the effects of metallic joint prosthesis on myocardial health. Copyright © 2017 Elsevier GmbH. All rights reserved.

Investigations on blood coagulation in the green iguana (Iguana iguana).

PubMed

Kubalek, S; Mischke, R; Fehr, M

2002-05-01

The prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, kaolin clotting time (KCT), dilute Russell's viper venom time (DRVVT) and reptilase time, as well as five different plasma fibrinogen assays [gravimetry, Jacobsson method (extinction at 280 nm), Millar method (heat precipitation), kinetic turbidometry, Clauss method] and resonance thrombography were performed in 26 clinically healthy green iguanas. All assays were carried out in comparison with pooled normal canine plasma. In iguana plasma, the PT [median (x0.50) = 453-831 s, dependent on the reagent], APTT (x0.50 = 170-242 s, dependent on the reagent), thrombin time (x0.50 = 118 - > 1000 s, dependent on thrombin activity), KCT (x0.50 = 274 s), DRVVT (x0.50 = 349 s) and reptilase time (all samples > 1000 s) were widely scattered at the limit of measurability. Only fibrinogen concentrations measured using the Jacobsson method (x0.50 = 4.40 g/l) correlated well (r = 0.91) with gravimetry (x0.50 = 4.22 g/l). The results of this study indicate a limited suitability and a confined diagnostic significance of the selected methods in the green iguana. This may be caused by the species specificity of certain components of the reagents used, as well as a less optimal test system, i.e. relationship of test reagent to clotting factor concentrations in iguana plasma.

A Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) Quantitative Analysis Method Based on the Auto-Selection of an Internal Reference Line and Optimized Estimation of Plasma Temperature.

PubMed

Yang, Jianhong; Li, Xiaomeng; Xu, Jinwu; Ma, Xianghong

2018-01-01

The quantitative analysis accuracy of calibration-free laser-induced breakdown spectroscopy (CF-LIBS) is severely affected by the self-absorption effect and estimation of plasma temperature. Herein, a CF-LIBS quantitative analysis method based on the auto-selection of internal reference line and the optimized estimation of plasma temperature is proposed. The internal reference line of each species is automatically selected from analytical lines by a programmable procedure through easily accessible parameters. Furthermore, the self-absorption effect of the internal reference line is considered during the correction procedure. To improve the analysis accuracy of CF-LIBS, the particle swarm optimization (PSO) algorithm is introduced to estimate the plasma temperature based on the calculation results from the Boltzmann plot. Thereafter, the species concentrations of a sample can be calculated according to the classical CF-LIBS method. A total of 15 certified alloy steel standard samples of known compositions and elemental weight percentages were used in the experiment. Using the proposed method, the average relative errors of Cr, Ni, and Fe calculated concentrations were 4.40%, 6.81%, and 2.29%, respectively. The quantitative results demonstrated an improvement compared with the classical CF-LIBS method and the promising potential of in situ and real-time application.

Submerged Glow-Discharge Plasma: An Economical Approach to Convert Construction Scrap Metal into Nanomaterials

NASA Astrophysics Data System (ADS)

Yek, Peter Nai Yuh; Rafiq Mirza Julaihi, Muhammad; Shahril Osman, Mohammad; Tiong, Tung Chuan; Lee, Wak Ha; Leing Lee, Chern

2018-03-01

Submerged glow-discharge plasma (SGDP) is relatively new among the various methods available for nanomaterials synthesis (NMs) techniques. This method allows great control over the production cost of nanomaterials synthesis. A lab-scale batch type SDGP technology has been constructed to produce nanomaterials and investigate the inter-relationship between plasma excitation voltages, electrodes submerged areas and electrolyte concentration. Metal oxide nanospheres has been synthesised from different electrolyte concentrations (1M-0.001M) and characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). As the major results showed that the nanospheres are uniformly spherical with diameter size distribution are between 100 nm - 2μm. EDS analysis shown the nano-Iron Oxide have been formed. Scrap metal initially showed around 6.45% and 93.55% of Carbon and Iron composition respectively. After SGDP process to the scrap metal, Carbon content has increased to 34-35% and Iron content has reduced to around 15-40%. EDS results also shown the higher percentage of Iron amount has remained with lower electrolyte concentration and Current is proportionally related to submersion area of cathode.

Lack of Association between Human Plasma Oxytocin and Interpersonal Trust in a Prisoner’s Dilemma Paradigm

PubMed Central

Christensen, James C.; Shiyanov, Pavel A.; Estepp, Justin R.; Schlager, John J.

2014-01-01

Expanding interest in oxytocin, particularly the role of endogenous oxytocin in human social behavior, has created a pressing need for replication of results and verification of assay methods. In this study, we sought to replicate and extend previous results correlating plasma oxytocin with trust and trustworthy behavior. As a necessary first step, the two most commonly used commercial assays were compared in human plasma via the addition of a known quantity of exogenous oxytocin, with and without sample extraction. Plasma sample extraction was found to be critical in obtaining repeatable concentrations of oxytocin. In the subsequent trust experiment, twelve samples in duplicate, from each of 82 participants, were collected over approximately six hours during the performance of a Prisoner’s Dilemma task paradigm that stressed human interpersonal trust. We found no significant relationship between plasma oxytocin concentrations and trusting or trustworthy behavior. In light of these findings, previous published work that used oxytocin immunoassays without sample extraction should be reexamined and future research exploring links between endogenous human oxytocin and trust or social behavior should proceed with careful consideration of methods and appropriate biofluids for analysis. PMID:25549255

Rapid determination of tafenoquine in small volume human plasma samples by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Doyle, E; Fowles, S E; Summerfield, S; White, T J

2002-03-25

A method was developed for the determination of tafenoquine (I) in human plasma using high-performance liquid chromatography-tandem mass spectrometry. Prior to analysis, the protein in plasma samples was precipitated with methanol containing [2H3(15N)]tafenoquine (II) to act as an internal standard. The supernatant was injected onto a Genesis-C18 column without any further clean-up. The mass spectrometer was operated in the positive ion mode, employing a heat assisted nebulisation, electrospray interface. Ions were detected in multiple reaction monitoring mode. The assay required 50 microl of plasma and was precise and accurate within the range 2 to 500 ng/ml. The average within-run and between-run relative standard deviations were < 7% at 2 ng/ml and greater concentrations. The average accuracy of validation standards was generally within +/- 4% of the nominal concentration. There was no evidence of instability of I in human plasma following three complete freeze-thaw cycles and samples can safely be stored for at least 8 months at approximately -70 degrees C. The method was very robust and has been successfully applied to the analysis of clinical samples from patients and healthy volunteers dosed with I.

Nitrous Oxide Anesthesia and Plasma Homocysteine in Adolescents

PubMed Central

Nagele, Peter; Tallchief, Danielle; Blood, Jane; Sharma, Anshuman; Kharasch, Evan D.

2011-01-01

Background Nitrous oxide inactivates vitamin B12, inhibits methionine synthase and consequently increases plasma total homocysteine (tHcy). Prolonged exposure to nitrous oxide can lead to neuropathy, spinal cord degeneration and even death in children. We tested the hypothesis that nitrous oxide anesthesia causes a significant increase in plasma tHcy in children. Methods Twenty-seven children (age 10-18 years) undergoing elective major spine surgery were enrolled and serial plasma samples from 0 – 96 hours after induction were obtained. The anesthetic regimen, including the use of nitrous oxide, was at the discretion of the anesthesiologist. Plasma tHcy was measured using standard enzymatic assays. Results The median baseline plasma tHcy concentration was 5.1 μmol/L (3.9 – 8.0 μmol/L, interquartile range) and increased in all patients exposed to nitrous oxide (n=26) by an average of +9.4 μmol/L (geometric mean; 95% CI 7.1 – 12.5 μmol/L) or +228% (mean; 95% CI 178% - 279%). Plasma tHcy peaked between 6-8 hours after induction of anesthesia. One patient who did not receive nitrous oxide had no increase in plasma tHcy. Several patients experienced a several-fold increase in plasma tHcy (max. +567%). The increase in plasma tHcy was strongly correlated with the duration and average concentration of nitrous oxide anesthesia (r= 0.80; p<0.001). Conclusions Pediatric patients undergoing nitrous oxide anesthesia develop significantly increased plasma tHcy concentrations. The magnitude of this effect appears to be greater compared to adults; however, the clinical relevance is unknown. PMID:21680854

Plasma Concentration of the Neurofilament Light Protein (NFL) is a Biomarker of CNS Injury in HIV Infection: A Cross-Sectional Study

PubMed Central

Gisslén, Magnus; Price, Richard W.; Andreasson, Ulf; Norgren, Niklas; Nilsson, Staffan; Hagberg, Lars; Fuchs, Dietmar; Spudich, Serena; Blennow, Kaj; Zetterberg, Henrik

2015-01-01

Background Cerebrospinal fluid (CSF) neurofilament light chain protein (NFL) is a sensitive marker of neuronal injury in a variety of neurodegenerative conditions, including the CNS dysfunction injury that is common in untreated HIV infection. However, an important limitation is the requirement for lumbar puncture. For this reason, a sensitive and reliable blood biomarker of CNS injury would represent a welcome advance in both clinical and research settings. Methods To explore whether plasma concentrations of NFL might be used to detect CNS injury in HIV infection, an ultrasensitive Single molecule array (Simoa) immunoassay was developed. Using a cross-sectional design, we measured NFL in paired CSF and plasma samples from 121 HIV-infected subjects divided into groups according to stage of their systemic disease, presence of overt HIV-associated dementia (HAD), and after antiretroviral treatment (ART)-induced viral suppression. HIV-negative controls were also examined. Findings Plasma and CSF NFL concentrations were very highly correlated (r = 0.89, P < 0.0001). While NFL was more than 50-fold lower plasma than CSF it was within the quantifiable range of the new plasma assay in all subjects, including the HIV negatives and the HIV positives with normal CSF NFL concentrations. The pattern of NFL changes were almost identical in plasma and CSF, both exhibiting similar age-related increases in concentrations along with highest values in HAD and substantial elevations in ART-naïve neuroasymptomatic subjects with low blood CD4+ T cells. Interpretation These results show that plasma NFL may prove a valuable tool to evaluate ongoing CNS injury in HIV infection that may be applied in the clinic and in research settings to assess the presence if active CNS injury. Because CSF NFL is also elevated in a variety of other CNS disorders, sensitive measures of plasma NFL may similarly prove useful in other settings. PMID:26870824

Validation of amino-acids measurement in dried blood spot by FIA-MS/MS for PKU management.

PubMed

Bruno, C; Dufour-Rainfray, D; Patin, F; Vourc'h, P; Guilloteau, D; Maillot, F; Labarthe, F; Tardieu, M; Andres, C R; Emond, P; Blasco, H

2016-09-01

Phenylketonuria (PKU) is a metabolic disorder leading to high concentrations of phenylalanine (Phe) and low concentrations of tyrosine (Tyr) in blood and brain that may be neurotoxic. This disease requires a regular monitoring of plasma Phe and Tyr as well as branched-chain amino-acids concentrations to adapt the Phe-restricted diet and other therapy that may be prescribed in PKU. We validated a Flow Injection Analysis tandem Mass Spectrometry (FIA-MS/MS) to replace the enzymatic method routinely used for neonatal screening in order to monitor in parallel to Phe, Tyr and branched-chain amino-acids not detected by the enzymatic method. We ascertained the performances of the method: linearity, detection and quantification limits, contamination index, accuracy. We cross validated the FIA-MS/MS and enzymatic methods and we evaluated our own reference ranges to monitor Phe, Tyr, Leu, Val on 59 dried blood spots of normal controls. We also evaluated Tyr, Leu and Val concentrations in PKU patients to detect some potential abnormalities, not evaluated by the enzymatic method. We developed a rapid method with excellent performances including precision and accuracy <15%. We noted an excellent correlation of Phe concentrations between FIA-MS/MS and enzymatic methods (p<0.0001) based on our database which are similar to references ranges published. We observed that 50% of PKU patients had lower concentrations of Tyr, Leu and/or Val that could not be detected by the enzymatic method. Based on laboratory accreditation recommendations, we validated a robust, rapid and reliable FIA-MS/MS method to monitor plasma Phe concentrations but also Tyr, Leu and Val concentrations, suitable for PKU management. We evaluated our own reference ranges of concentration for a routine application of this method. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Procollagen III N-terminal Propeptide and Desmosine are Released by Matrix Destruction in Pulmonary Tuberculosis

PubMed Central

Seddon, Jo; Kasprowicz, Victoria; Walker, Naomi F.; Yuen, Ho Ming; Sunpath, Henry; Tezera, Liku; Meintjes, Graeme; Wilkinson, Robert J.; Bishai, William R.; Friedland, Jon S.; Elkington, Paul T.

2013-01-01

Background. Tuberculosis is transmitted by patients with pulmonary disease. Matrix metalloproteinases (MMPs) drive lung destruction in tuberculosis but the resulting matrix degradation products (MDPs) have not been studied. We investigate the hypothesis that MMP activity generates matrix turnover products as correlates of lung pathology. Methods. Induced sputum and plasma were collected prospectively from human immunodeficiency virus (HIV) positive and negative patients with pulmonary tuberculosis and controls. Concentrations of MDPs and MMPs were analyzed by ELISA and Luminex array in 2 patient cohorts. Results. Procollagen III N-terminal propeptide (PIIINP) was 3.8-fold higher in induced sputum of HIV-uninfected tuberculosis patients compared to controls and desmosine, released during elastin degradation, was 2.4-fold higher. PIIINP was elevated in plasma of tuberculosis patients. Plasma PIIINP correlated with induced sputum MMP-1 concentrations and radiological scores, demonstrating that circulating MDPs reflect lung destruction. In a second patient cohort of mixed HIV seroprevalence, plasma PIIINP concentration was increased 3.0-fold above controls (P < .001). Plasma matrix metalloproteinase-8 concentrations were also higher in tuberculosis patients (P = .001). Receiver operating characteristic analysis utilizing these 2 variables demonstrated an area under the curve of 0.832 (P < .001). Conclusions. In pulmonary tuberculosis, MMP-driven immunopathology generates matrix degradation products. PMID:23922364

Simultaneous and rapid determination of gefitinib, erlotinib and afatinib plasma levels using liquid chromatography/tandem mass spectrometry in patients with non-small-cell lung cancer.

PubMed

Hayashi, Hideki; Kita, Yutaro; Iihara, Hirotoshi; Yanase, Koumei; Ohno, Yasushi; Hirose, Chiemi; Yamada, Maya; Todoroki, Kenichiro; Kitaichi, Kiyoyuki; Minatoguchi, Shinya; Itoh, Yoshinori; Sugiyama, Tadashi

2016-07-01

A simultaneous, selective, sensitive and rapid liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of gefitinib, erlotinib and afatinib in 250 μL samples of human blood plasma. Diluted plasma samples were extracted using a liquid-phase extraction procedure with tert-butyl methyl ether. The three drugs were separated by high-performance liquid chromatography using a C18 column and an isocratic mobile phase running at a flow rate of 0.2 mL/min for 5 min. The drugs were detected using a tandem mass spectrometer with electrospray ionization using imatinib as an internal standard. Calibration curves were generated over the linear concentration range of 0.05-100 nm in plasma with a lower limit of quantification of 0.01 or 0.05 nm for all compounds. Finally, the validated method was applied to a clinical pharmacokinetic study in patients with nonsmall-cell lung cancer (NSCLC) following the oral administration of afatinib. These results indicate that this method is suitable for assessing the risks and benefits of chemotherapy in patients with NSCLC and is useful for therapeutic drug monitoring for NSCLC treatment. As far as we know, this is the first report on LC-MS/MS method for the simultaneous quantification of NSCLC tyrosine kinase inhibitor plasma concentrations including afatinib. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

A Novel Chronic Opioid Monitoring Tool to Assess Prescription Drug Steady State Levels in Oral Fluid.

PubMed

Shaparin, Naum; Mehta, Neel; Kunkel, Frank; Stripp, Richard; Borg, Damon; Kolb, Elizabeth

2017-11-01

Interpretation limitations of urine drug testing and the invasiveness of blood toxicology have motivated the desire for the development of simpler methods to assess biologically active drug levels on an individualized patient basis. Oral fluid is a matrix well-suited for the challenge because collections are based on simple noninvasive procedures and drug concentrations better correlate to blood drug levels as oral fluid is a filtrate of the blood. Well-established pharmacokinetic models were utilized to generate oral fluid steady state concentration ranges to assess the interpretive value of the alternative matrix to monitor steady state plasma oxycodone levels. Paired oral fluid and plasma samples were collected from patients chronically prescribed oxycodone and quantitatively analyzed by liquid chromatography tandem mass spectrometry. Steady state plasma concentration ranges were calculated for each donor and converted to an equivalent range in oral fluid. Measured plasma and oral fluid oxycodone concentrations were compared with respective matrix-matched steady state ranges, using each plasma steady state classification as the control. A high degree of correlation was observed between matrices when classifying donors according to expected steady state oxycodone concentration. Agreement between plasma and oral fluid steady state classifications was observed in 75.6% of paired samples. This study supports novel application of basic pharmacokinetic knowledge to the pain management industry, simplifying and improving individualized drug monitoring and risk assessment through the use of oral fluid drug testing. Many benefits of established therapeutic drug monitoring in plasma can be realized in oral fluid for patients chronically prescribed oxycodone at steady state. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Effect of capture stress on plasma enzyme activities in rainbow trout (Salmo gairdneri)

USGS Publications Warehouse

Bouck, G.R.; Cairns, M. A.; Christian, A. R.

1978-01-01

Four capture methods were used to collect domesticated rainbow trout (Salmo gairdneri): angling, electroshocking, seining, and direct netting (control). Blood was sampled rapidly upon capture, usually within 2 min. No significant differences were noted within the time frame of the experiment between the four capture groups for plasma protein concentration, lactate dehydrogenase activity, or leucine aminonaphthylamidase activity. Creatine phosphokinase activity was elevated among electroshocked fish. Acid phosphatase activity was too low for accurate measurement. Hematocrits were significantly elevated by capture struggles. These results indicate that these capture methods do not preclude the use of plasma enzyme levels for investigating the health of wild fish. Key words: plasma enzyme, capture stress, physiology, plasma protein, rainbow trout, lactate dehydrogenase, leucine aminonaphthylamidase, creatine phosphokinase

Rapid analysis of pharmaceuticals and personal care products in fish plasma micro-aliquots using liquid chromatography tandem mass spectrometry.

PubMed

Chen, Fangfang; Gong, Zhiyuan; Kelly, Barry C

2015-02-27

A sensitive analytical method based on liquid-liquid extraction (LLE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for rapid analysis of 11 pharmaceuticals and personal care products (PPCPs) in fish plasma micro-aliquots (∼20μL). Target PPCPs included, bisphenol A, carbamazepine, diclofenac, fluoxetine, gemfibrozil, ibuprofen, naproxen, risperidone, sertraline, simvastatin and triclosan. A relatively quicker and cheaper LLE procedure exhibited comparable analyte recoveries with solid-phase extraction. Rapid separation and analysis of target compounds in fish plasma extracts was achieved by employing a high efficiency C-18 HPLC column (Agilent Poroshell 120 SB-C18, 2.1mm×50mm, 2.7μm) and fast polarity switching, enabling effective monitoring of positive and negative ions in a single 9min run. With the exception of bisphenol A, which exhibited relatively high background contamination, method detection limits of individual PPCPs ranged between 0.15 and 0.69pg/μL, while method quantification limits were between 0.05 and 2.3pg/μL. Mean matrix effect (ME) values ranged between 65 and 156% for the various target analytes. Isotope dilution quantification using isotopically labelled internal surrogates was utilized to correct for signal suppression or enhancement and analyte losses during sample preparation. The method was evaluated by analysis of 20μL plasma micro-aliquots collected from zebrafish (Danio rerio) from a laboratory bioaccumulation study, which included control group fish (no exposure), as well as fish exposed to environmentally relevant concentrations of PPCPs. Using the developed LC-MS/MS based method, concentrations of the studied PPCPs were consistently detected in the low pg/μL (ppb) range. The method may be useful for investigations requiring fast, reliable concentration measurements of PPCPs in fish plasma. In particular, the method may be applicable for in situ contaminant biomonitoring, as well as bioaccumulation and toxicology studies employing small fishes with low blood compartment volumes. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of atomoxetine on the QT interval in healthy CYP2D6 poor metabolizers

PubMed Central

Loghin, Corina; Haber, Harry; Beasley, Charles M; Kothare, Prajakti A; Kauffman, Lynnette; April, John; Jin, Ling; Allen, Albert J; Mitchell, Malcolm I

2013-01-01

Aim The effects of atomoxetine (20 and 60 mg twice daily), 400 mg moxifloxacin and placebo on QTc in 131 healthy CYP2D6 poor metabolizer males were compared. Methods Atomoxetine doses were selected to result in plasma concentrations that approximated expected plasma concentrations at both the maximum recommended dose and at a supratherapeutic dose in CYP2D6 extensive metabolizers. Ten second electrocardiograms were obtained for time-matched baseline on days −2 and −1, three time points after dosing on day 1 for moxifloxacin and five time points on day 7 for atomoxetine and placebo. Maximum mean placebo-subtracted change from baseline model-corrected QT (QTcM) on day 7 was the primary endpoint. Results QTcM differences for atomoxetine 20 and 60 mg twice daily were 0.5 ms (upper bound of the one-sided 95% confidence interval 2.2 ms) and 4.2 ms (upper bound of the one-sided 95% confidence interval 6.0 ms), respectively. As plasma concentration of atomoxetine increased, a statistically significant increase in QTc was observed. The moxifloxacin difference from placebo met the a priori definition of non-inferiority. Maximum mean placebo-subtracted change from baseline QTcM for moxifloxacin was 4.8 ms and this difference was statistically significant. Moxifloxacin plasma concentrations were below the concentrations expected from the literature. However, the slope of the plasma concentration−QTc change observed was consistent with the literature. Conclusion Atomoxetine was not associated with a clinically significant change in QTc. However, a statistically significant increase in QTc was associated with increasing plasma concentrations. PMID:22803597

A Pilot Study of the Usefulness of a Single Olanzapine Plasma Concentration as an Indicator of Early Drug Effect in a Small Sample of First-Episode Psychosis Patients

PubMed Central

Zabala, Arantzazu; Bustillo, Mariana; Querejeta, Imanol; Alonso, Marta; Mentxaka, Oiane; González-Pinto, Ana; Ugarte, Amaia; Meana, J. Javier; Gutiérrez, Miguel; Segarra, Rafael

2017-01-01

Abstract Purpose/Background Studies analyzing concentration-effect relationships in second-generation antipsychotics have reported contradictory results in chronic schizophrenia. No data are available for the early stages of the disease. The present study aims to evaluate the association between a single olanzapine plasma concentration, clinical response, and severity of adverse effects in first-episode psychosis (FEP); to test the utility of various plasma breakpoints as markers of early response to treatment; and to identify variables affecting olanzapine concentrations. Methods Data from 23 compliant FEP patients receiving olanzapine monotherapy (5–30 mg/d) were evaluated 2 months after beginning treatment. Clinical symptoms were assessed using the Positive and Negative Syndrome Scale and the Montgomery-Åsberg Depression Rating Scale. Adverse effects were rated using the Udvalg for Kliniske Undersøgelser scale. Plasma samples were drawn at 11 (SD, 1) hours after dosing and analyzed with high-performance liquid chromatography/tandem mass spectrometry. Findings Consistent with findings on chronic disease, dose, age, sex, weight, and cigarettes/day accounted for some of the variability in olanzapine concentrations. While no relationship was found between olanzapine concentrations and adverse effects or improvement of depressive symptoms, response of psychotic symptoms was associated with concentrations between 22.56 and 77.92 ng/mL. Plasma breakpoints did not show sufficiently high specificity, resulting in a large number of false-positive results. Implications Although olanzapine concentrations do not seem to be reliable indicators of early drug effect in FEP, they may still prove useful for detecting noncompliance, as well as pharmacokinetically relevant comorbidities or genetic particularities in drug metabolism. PMID:28796022

The relationship between the plasma concentration of blonanserin, and its plasma anti-serotonin 5-HT(2A) activity/anti-dopamine D₂ activity ratio and drug-induced extrapyramidal symptoms.

PubMed

Suzuki, Hidenobu; Gen, Keishi

2012-03-01

 Blonanserin is a second-generation antipsychotic that was developed in Japan. We investigated the relationships between plasma concentration, the plasma anti-5-HT(2A) activity/anti-D₂ activity (S/D) ratio and extrapyramidal symptoms (EPS) in blonanserin dosing.  The subjects were 29 outpatients with schizophrenia. We assessed EPS using the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). The plasma concentrations were measured by high performance liquid chromatography, and the plasma anti-D₂ and anti-5-HT(2A) activities were measured by [³H]-spiperone and [³H]-ketanserin radioreceptor assays. The results revealed that there were significant correlations between both the plasma concentration and the DIEPSS total score (P<0.05). A negative correlative tendency was found between the S/D ratio and the DIEPSS total score. Furthermore, the plasma concentrations were divided into a low plasma concentration group and a high plasma concentration group, and the S/D ratios were divided into a low S/D ratio group and a high S/D ratio group. We then compared each group based on the DIEPSS total scores. The score in the high plasma concentration-low S/D ratio group was significantly higher than in the high plasma concentration-high S/D ratio, low plasma concentration-high S/D ratio and low plasma concentration-low S/D ratio groups (P<0.05 for all).  These findings indicate that the incidence of EPS during treatment with blonanserin is mainly determined by plasma concentration, but the incidence of EPS may be inhibited when anti-5HT(2A) activity is predominant over anti-D₂ activity. © 2012 The Authors. Psychiatry and Clinical Neurosciences © 2012 Japanese Society of Psychiatry and Neurology.

Pharmacokinetics of Maxing Shigan decoction in normal rats and RSV pneumonia model rats by HPLC-MS/MS.

PubMed

Jiang, Li; Gao, Meng; Qu, Fei; Li, Hui-lan; Yu, Lan-bin; Rao, Yi; Wang, Yue-sheng; Xu, Guo-liang

2015-07-01

To establish a LC-MS/MS method to determine the concentrations of liquiritin, glycyrrhizin, glycyrrhetinic acid, amygdalin, amygdalin prunasin, ephedrine, pseudoephedrine and methylephedrine of Maxing Shigan decoction in rat plasma, and study the differences on their pharmacokinetic process in normal rats and RSV pneumonia model rats. After normal rats and RSV pneumonia model rats were orally administered with Maxing Shigan decoction, the blood was collected from retinal vein plexus of different time points. Specifically, tetrahydropalmatine was taken as internal standard for determining ephedrine, while chloramphenicol was taken as internal standard for determining other components. After plasma samples were pre-treated as the above, the supernatant was dried with nitrogen blowing concentrator and then redissolved with methylalcohol. The chromatography was eluted with mobile phase consisted of acetonitrile and 0.1% formic acid solution in a gradient manner. ESI sources were adopted to scan ingredients in ephedra in a positive ion scanning mode and other ingredientsin a negative ion scanning mode. The multiple-reaction monitoring (MRM) method was developed the plasma concentration of each active component. The pharmacokinetic parameters of each group were calculated by using Win-Nonlin 4.1 software and put into the statistical analysis. The result showed the plasma concentration of the eight active ingredients, i.e., liquiritin, glycyrrhizin, glycyrrhetinic acid, amygdalin, amygdalin prunasin, ephedrine, pseudoephedrine and methylephedrine within the ranges of 1.04-1040, 1.04-1040, 0.89-445, 1.05-4200, 1.25-2490, 0.3-480, 0.3-480, 0.3-480 microg x L(-1), with a good linearity and satisfactory precision, recovery and stability in the above ingredients. After modeling, except for glycyrrhetinic acid whose pharmacokinetic parameters were lacked due to the data missing, all of the rest components showed significant higher Cmax, AUC(0-1) and lower clearance rate (CL) than that of the normal group, indicating the increase in absorption in rats in the pathological state by reducing the clearance rate. The method is accurate and sensitive and so can be used to determine the plasma concentrations of the eight active ingredients in Maxing Shigan decoction. RSV pneumonia-infected rats absorbed more ingredients in Maxing Shigan decoction.

Ultra-high performance liquid chromatographic determination of levofloxacin in human plasma and prostate tissue with use of experimental design optimization procedures.

PubMed

Szerkus, O; Jacyna, J; Wiczling, P; Gibas, A; Sieczkowski, M; Siluk, D; Matuszewski, M; Kaliszan, R; Markuszewski, M J

2016-09-01

Fluoroquinolones are considered as gold standard for the prevention of bacterial infections after transrectal ultrasound guided prostate biopsy. However, recent studies reported that fluoroquinolone- resistant bacterial strains are responsible for gradually increasing number of infections after transrectal prostate biopsy. In daily clinical practice, antibacterial efficacy is evaluated only in vitro, by measuring the reaction of bacteria with an antimicrobial agent in culture media (i.e. calculation of minimal inhibitory concentration). Such approach, however, has no relation to the treated tissue characteristics and might be highly misleading. Thus, the objective of this study was to develop, with the use of Design of Experiments approach, a reliable, specific and sensitive ultra-high performance liquid chromatography- diode array detection method for the quantitative analysis of levofloxacin in plasma and prostate tissue samples obtained from patients undergoing prostate biopsy. Moreover, correlation study between concentrations observed in plasma samples vs prostatic tissue samples was performed, resulting in better understanding, evaluation and optimization of the fluoroquinolone-based antimicrobial prophylaxis during transrectal ultrasound guided prostate biopsy. Box-Behnken design was employed to optimize chromatographic conditions of the isocratic elution program in order to obtain desirable retention time, peak symmetry and resolution of levofloxacine and ciprofloxacine (internal standard) peaks. Fractional Factorial design 2(4-1) with four center points was used for screening of significant factors affecting levofloxacin extraction from the prostatic tissue. Due to the limited number of tissue samples the prostatic sample preparation procedure was further optimized using Central Composite design. Design of Experiments approach was also utilized for evaluation of parameter robustness. The method was found linear over the range of 0.030-10μg/mL for human plasma and 0.300-30μg/g for human prostate tissue samples. The intra-day and inter-day variability for levofloxacine from both plasma and prostate samples were less than 10%, with accuracies between 93 and 108% of the nominal values. The limit of detection and the limit of quantification for human plasma were 0.01μg/mL and 0.03μg/mL, respectively. For the prostate tissue, the limit of detection and the limit of quantification were 0.1μg/g and 0.3μg/g, respectively. The average recoveries of levofloxacin were in the range from 99 to 106%. Also, the method fulfills requirements of robustness what was determined and proved by Design of Experiments. The developed method was successfully applied to examine prostate tissue and plasma samples from 140 hospitalized patients enrolled into the clinical study, 12h after oral administration of LVF at a dose of 500mg. The mean (±SD) LVF concentration in prostate was 6.22±3.52μg/g and in plasma 2.54±1.14μg/mL. Due to simplicity of the method and relative small amount of sample needed for the assay, the method can be applied in clinical practice for monitoring of LVF concentrations in plasma and prostate gland. Copyright © 2016 Elsevier B.V. All rights reserved.

[RP-HPLC method for determination of protopine in plasma and pharmacokinetics in rats].

PubMed

Yang, D L; Huang, X N; Sun, A S; Huang, B; Ye, L; Shi, J S

2001-10-01

To develop a reversed phase high performance liquid chromatographic method (RP-HPLC) for determination of protopine (Pro) in rat plasma and to investigate the pharmacokinetics of Pro in rats. The column was packed with 5 microns C18. The mobile phase (pH 5.6) was a mixture of methanol-water-10% acetic acid (80:20:2). After twice extracted with ether under basic condition, and reextracted with 0.02 mol.L-1 sulfuric acid, protopine in the plasma samples was isolated well. The content of protopine in the plasma sample was measured by UV detector at 285 nm. The lowest limit of detection was 50 ng.mL-1. The intraday and interday precisions were 1.5%-3.0% and 2.1%-6.2%, respectively. The mean recovery was 80.6%-97.6%. A good linear relationship between the peak height and the concentration of protopine in rat plasma was observed. The pharmacokinetics of protopine had been investigated in rats after intravenous administration 10 mg.kg-1. The concentration-time curve of protopine in rat was confirmed to two-compartment open model. The T1/2 alpha, T1/2 beta, Ke, CL, Vd were 0.05 h, 1.85 h, 1.52 h, 6.41 L.h-1 and 17.27 L, respectively. This method is suitable for studies on pharmacokinetics of protopine.

Validation of an assay for quantification of free normetanephrine, metanephrine and methoxytyramine in plasma by high performance liquid chromatography with coulometric detection: Comparison of peak-area vs. peak-height measurements.

PubMed

Nieć, Dawid; Kunicki, Paweł K

2015-10-01

Measurements of plasma concentrations of free normetanephrine (NMN), metanephrine (MN) and methoxytyramine (MTY) constitute the most diagnostically accurate screening test for pheochromocytomas and paragangliomas. The aim of this article is to present the results from a validation of an analytical method utilizing high performance liquid chromatography with coulometric detection (HPLC-CD) for quantifying plasma free NMN, MN and MTY. Additionally, peak integration by height and area and the use of one calibration curve for all batches or individual calibration curve for each batch of samples was explored as to determine the optimal approach with regard to accuracy and precision. The method was validated using charcoal stripped plasma spiked with solutions of NMN, MN, MTY and internal standard (4-hydroxy-3-methoxybenzylamine) with the exception of selectivity which was evaluated by analysis of real plasma samples. Calibration curve performance, accuracy, precision and recovery were determined following both peak-area and peak-height measurements and the obtained results were compared. The most accurate and precise method of calibration was evaluated by analyzing quality control samples at three concentration levels in 30 analytical runs. The detector response was linear over the entire tested concentration range from 10 to 2000pg/mL with R(2)≥0.9988. The LLOQ was 10pg/mL for each analyte of interest. To improve accuracy for measurements at low concentrations, a weighted (1/amount) linear regression model was employed, which resulted in inaccuracies of -2.48 to 9.78% and 0.22 to 7.81% following peak-area and peak-height integration, respectively. The imprecisions ranged from 1.07 to 15.45% and from 0.70 to 11.65% for peak-area and peak-height measurements, respectively. The optimal approach to calibration was the one utilizing an individual calibration curve for each batch of samples and peak-height measurements. It was characterized by inaccuracies ranging from -3.39 to +3.27% and imprecisions from 2.17 to 13.57%. The established HPLC-CD method enables accurate and precise measurements of plasma free NMN, MN and MTY with reasonable selectivity. Preparing calibration curve based on peak-height measurements for each batch of samples yields optimal accuracy and precision. Copyright © 2015. Published by Elsevier B.V.

Comparison of Plasma, Saliva, and Hair Levetiracetam Concentrations.

PubMed

Karaś-Ruszczyk, Katarzyna; Kuczyńska, Julita; Sienkiewicz-Jarosz, Halina; Kurkowska-Jastrzębska, Iwona; Bienkowski, Przemyslaw; Restel, Magdalena; Samochowiec, Jerzy; Mierzejewski, Pawel

2017-06-01

Previous findings revealed high correlations between serum/plasma and saliva levetiracetam concentrations, indicating saliva as an alternative matrix for monitoring levetiracetam therapy. Levetiracetam concentration in the hair, which could reflect long-term drug exposure and patients' compliance, has not been systematically tested, as yet. The aim of this study was to determine the correlation between plasma, saliva, and hair levetiracetam concentrations in 47 patients with epilepsy. Plasma, saliva, and hair levetiracetam concentrations were measured by liquid chromatography-tandem mass spectrometry with positive ionization. Levetiracetam saliva and plasma concentrations were highly correlated (r = 0.93). Plasma concentrations were not influenced by sex, age, and other concomitant antiepileptic drugs. Levetiracetam hair concentrations correlated with plasma concentrations (r = 0.36) but not daily dose (mg/kg). Drug hair concentrations were not influenced by hair color or treatment (dyed). The results tend to indicate that saliva may be a reliable alternative to plasma for monitoring levetiracetam concentrations. Levetiracetam can also be detected in human hair.

Effects of running the Bostom Marathon on plasma concentrations of large neutral amino acids

NASA Technical Reports Server (NTRS)

Conlay, L. A.; Wurtman, R. J.; Lopez G-Coviella, I.; Blusztajn, J. K.; Vacanti, C. A.; Logue, M.; During, M.; Caballero, B.; Maher, T. J.; Evoniuk, G.

1989-01-01

Plasma large neutral amino acid concentrations were measured in thirty-seven subjects before and after completing the Boston Marathon. Concentrations of tyrosine, phenylalanine, and methionine increased, as did their 'plasma ratios' (i.e., the ratio of each amino acid's concentration to the summed plasma concentrations of the other large neutral amino acids which compete with it for brain uptake). No changes were noted in the plasma concentrations of tryptophan, leucine, isoleucine, nor valine; however, the 'plasma ratios' of valine, leucine, and isoleucine all decreased. These changes in plasma amino acid patterns may influence neurotransmitter synthesis.

Influence of calcium salts and bovine thrombin on growth factor release from equine platelet-rich gel supernatants.

PubMed

Giraldo, Carlos E; Álvarez, María E; Carmona, Jorge U

2017-01-16

To compare five activation methods in equine platelet-rich plasma (PRP) by determination of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta 1 (TGF-β1) concentrations in platelet-rich gel (PRG) supernatants. Platelet-rich plasma from 20 horses was activated by calcium chloride (CC), calcium gluconate (CG), bovine thrombin (BT), and their combinations, BTCC and BTCG. Both growth factor concentrations in PRG supernatants were measured by ELISA and compared with plasma and platelet lysates (PL) over time. Growth factor concentrations were significantly lower in plasma and higher for all PRG supernatants. Platelet lysates contained a significantly lower concentration of PDGF-BB than PRG supernatants and a significantly higher concentration of TGF-β1 than PRG supernatants. Clots from PRP activated with sodium salts were more stable over time and had significant growth factor release, whereas CC produced gross salt deposition. Significant correlations were noticed for platelet with leukocyte concentrations in PRP (r s : 0.76), platelet counts in PRP with TGF-β1 concentrations in PRG supernatants (r s : 0.86), platelet counts in PRP with PDGF-BB concentrations in PRG supernatants (r s : 0.78), leukocyte counts in PRP with TGF-β1 concentrations in PRG supernatants (r s : 0.76), and PDGF-BB concentrations with activating substances (r s : 0.72). Calcium gluconate was the better substance to induce PRP activation. It induced growth factor release free from calcium precipitates in the clots. Use of BT alone or combined with calcium salts was not advantageous for growth factor release.

Profile of disposition, tissue distribution and excretion of the novel anti-human immunodeficiency virus (HIV) agent W-1 in rats.

PubMed

Lu, Ying-Yuan; Wang, Xiao-Wei; Wang, Xin; Dai, Wen-Bing; Zhang, Qiang; Li, Pu; Lou, Ya-Qing; Lu, Chuang; Liu, Jun-Yi; Zhang, Guo-Liang

2016-07-01

The purpose of this study was to characterize the disposition, distribution, excretion and plasma protein binding of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1) in rats. Concentrations of W-1 within biological samples were determined using a validated high performance liquid chromatography method. The plasma protein binding of W-1 was examined by equilibrium dialysis method. After oral administration of W-1 (50, 100 and 200 mg/kg, respectively) in self-microemulsifying drug delivery system formulation, the pharmacokinetic parameters of W-1 were as follows: the peak plasma concentrations (C max) were 0.42, 1.50 and 2.55 μg/mL, the area under the curve (AUC0-t) were 0.89, 2.27 and 3.96 µg/h mL and the plasma half-life (t 1/2) were 5.15, 3.77 and 3.77 h, respectively. Moreover, the prototype of W-1 was rapidly and extensively distributed into fifteen tissues, especially higher concentrations were detected in intestine, stomach and liver, respectively. The plasma protein binding of W-1 in rat, beagle dog and human were in the range of 97.96-99.13 %. This study suggested that W-1 has an appropriate pharmacokinetics in rats, such as rapid absorption, moderate clearance, and rapid distribution to multiple tissues. Those properties provide important information for further development W-1 as an anti-HIV-1 drug candidate.

Scattering characteristics of electromagnetic waves in time and space inhomogeneous weakly ionized dusty plasma sheath

NASA Astrophysics Data System (ADS)

Guo, Li-xin; Chen, Wei; Li, Jiang-ting; Ren, Yi; Liu, Song-hua

2018-05-01

The dielectric coefficient of a weakly ionised dusty plasma is used to establish a three-dimensional time and space inhomogeneous dusty plasma sheath. The effects of scattering on electromagnetic (EM) waves in this dusty plasma sheath are investigated using the auxiliary differential equation finite-difference time-domain method. Backward radar cross-sectional values of various parameters, including the dust particle radius, charging frequency of dust particles, dust particle concentration, effective collision frequency, rate of the electron density variation with time, angle of EM wave incidence, and plasma frequency, are analysed within the time and space inhomogeneous plasma sheath. The results show the noticeable effects of dusty plasma parameters on EM waves.

Tin speciation in the femtogram range in open ocean seawater by gas chromatography/inductively coupled plasma mass spectrometry using a shield torch at normal plasma conditions.

PubMed

Tao, H; Rajendran, R B; Quetel, C R; Nakazato, T; Tominaga, M; Miyazaki, A

1999-10-01

A sensitive method for the determination of ultratrace organotin species in seawater is described. The merits and demerits of derivatization methods using Grignard reagent or sodium tetraethylborate (NaBEt4) were evaluated in terms of derivatization efficiency, applicability to the programmed temperature vaporization (PTV) method, and procedural blanks. The sensitivity of the gas chromatography/inductively coupled plasma mass spectrometry (GC/ICPMS) was improved by more than 100-fold by operating the shield torch at normal plasma conditions, compared with that obtained without using it. The absolute detection limit as tin reached subfemtogram (fg) levels. Furthermore, the detection limit in terms of relative concentration was improved 100-fold by using the PTV method, which enabled the injection of a large sample volume of as much as 100 microL without loss of analyte. When the organotin species in seawater were extracted into hexane with a preconcentration factor of 1000 after ethylation with NaBEt4 and a 100 microL aliquot of the extract was injected into the GC, the instrumental detection limit in relative concentration reached 0.01 pg/L in original seawater. Sources of contamination of organotin species during the sample preparation were examined, and a purification method of NaBEt4 was developed. Finally, the method was successfully applied to open ocean seawater samples containing organotin species at the level of 1-100 pg/L.

Association between body weight and composition and plasma 25 hydroxyvitamin D level in the diabetes prevention program

USDA-ARS?s Scientific Manuscript database

Objective: We examined associations between body weight and plasma 25-hydroxyvitamin D concentration (25OHD) in prediabetes and sought to estimate the impact of adiposity on these associations. Methods: The study was conducted in the placebo (n = 1082) and intensive lifestyle (n = 1079) groups of ...

Catalytic Bioscavengers Human Butyrylcholinesterase and Paraoxonase Sequestered to the Center for CNS

DTIC Science & Technology

2010-04-01

of radiolabeling fusion proteins without the denaturing effects coincident with oxidative radio-iodination associated with the chloramine T method...organ PS product = [(%ID/g)/AUC]*1000 Reportable Outcomes (1) The plasma concentration decay curve for AGT-185 is shown in Figure 1. The % of...injected dose (ID)/mL decreases rapidly in plasma following IV injection. This plasma decay curve was fit to the bi-exponential equation described above

Plasma Concentrations of Per- and Polyfluoroalkyl Substances at Baseline and Associations with Glycemic Indicators and Diabetes Incidence among High-Risk Adults in the Diabetes Prevention Program Trial

PubMed Central

Cardenas, Andres; Gold, Diane R.; Hauser, Russ; Kleinman, Ken P.; Hivert, Marie-France; Calafat, Antonia M.; Ye, Xiaoyun; Webster, Thomas F.; Horton, Edward S.

2017-01-01

Background: Several per- and polyfluoroalkyl substances (PFAS) are ubiquitous anthropogenic pollutants almost universally detected in humans. Experimental evidence indicates that PFAS alter glucose metabolism and insulin secretion. However, epidemiological studies have yielded inconsistent results. Objective: We sought to examine associations between plasma PFAS concentrations, glycemic indicators, and diabetes incidence among high-risk adults. Methods: Within the Diabetes Prevention Program (DPP), a trial for the prevention of type 2 diabetes among high-risk individuals, we quantified baseline plasma concentrations of nine PFAS among 957 participants randomized to a lifestyle intervention or placebo. We evaluated adjusted associations for plasma PFAS concentrations with diabetes incidence and key glycemic indicators measured at baseline and annually over up to 4.6 y. Results: Plasma PFAS concentrations were similar to those reported in the U.S. population in 1999–2000. At baseline, in cross-sectional analysis, a doubling in plasma perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) concentrations was associated with higher homeostatic model assessment of insulin resistance (HOMA-IR) [βPFOS=0.39; 95% confidence interval (CI): 0.13, 0.66; βPFOA=0.64; 95% CI: 0.34, 0.94], β-cell function (HOMA-β) (βPFOS=9.62; 95% CI: 1.55, 17.70; βPFOA=15.93; 95% CI: 6.78, 25.08), fasting proinsulin (βPFOS=1.37 pM; 95% CI: 0.50, 2.25; βPFOA=1.71 pM; 95% CI: 0.72, 2.71), and glycated hemoglobin (HbA1c) (βPFOS=0.03%; 95% CI: 0.002, 0.07; βPFOA=0.04%; 95% CI: 0.001, 0.07). There was no strong evidence of associations between plasma PFAS concentrations and diabetes incidence or prospective changes in glycemic indicators during the follow-up period. Conclusions: At baseline, several PFAS were cross-sectionally associated with small differences in markers of insulin secretion and β-cell function. However, there was limited evidence suggesting that PFAS concentrations are associated with diabetes incidence or changes in glycemic indicators during the follow-up period. https://doi.org/10.1289/EHP1612 PMID:28974480

Radioimmunoassay and chromatographic similarity of circulating endogenous gonadotropin releasing hormone and hypothalamic extracts in man. [/sup 125/I tracer technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mortimer, C.H.; McNeilly, A.S.; Rees, L.H.

1976-10-01

A highly sensitive radioimmunoassay for the gonadotropin releasing hormone has been developed in order to study its physiological importance in man. In view of the expected low concentrations in peripheral blood, large volumes of human plasma were extracted by two different methods and the characteristics of the radioimmunoassayable material compared with those of synthetic decapeptide and extracts of human hypothalami. The results indicate that radioimmunoassayable gonadotropin releasing hormone is present in some human plasmas but the plasma concentrations are less than 2.5 pg/ml. Peripheral levels were more consistently measurable in women at midcycle and after the menopause. The hormone wasmore » undetectable in the plasma of normal men, human cerebrospinal fluid, and fetal cerebral tissue, but was present in fetal hypothalami.« less

Effects of Sugar-sweetened Beverages on plasma Acylation Stimulating Protein, Leptin & Adiponectin and Metabolic Parameters

PubMed Central

Rezvani, Reza; Cianflone, Katherine; McGahan, John P.; Berglund, Lars; Bremer, Andrew A.; Keim, Nancy L.; Griffen, Steven C.; Havel, Peter J.; Stanhope, Kimber L.

2013-01-01

Objective We determined the effects of fructose and glucose consumption on plasma acylation stimulating protein (ASP), adiponectin, and leptin concentrations relative to energy intake, body weight, adiposity, circulating triglycerides, and insulin sensitivity. Design and Methods 32 overweight/obese adults consumed glucose- or fructose-sweetened beverages (25% energy requirement) with their ad libitum diets for 8 weeks, followed by sweetened beverage consumption for 2 weeks with a standardized, energy-balanced diet. Plasma variables were measured at baseline, 2, 8 and 10 weeks, and body adiposity and insulin sensitivity at baseline and 10 weeks. Results Fasting and postprandial ASP concentrations increased at 2 and/or 8 weeks. ASP increases correlated with changes in late-evening triglyceride concentrations. At 10 weeks, fasting adiponectin levels decreased in both groups, and decreases were inversely associated with baseline intra-abdominal fat volume. Sugar consumption increased fasting leptin concentrations; increases were associated with body weight changes. 24-h leptin profiles increased during glucose consumption and decreased during fructose consumption. These changes correlated with changes of 24-h insulin levels. Conclusions The consumption of fructose and glucose beverages induced changes in plasma concentrations of ASP, adiponectin and leptin. Further study is required to determine if these changes contribute to the metabolic dysfunction observed during fructose consumption. PMID:23512943

Concentrations of amino acids in plasma from 45- to 47-week gestation mares and foetuses (Equus caballus).

PubMed

Zicker, S C; Vivrette, S; Rogers, Q R

1994-06-01

Concentrations of 16 of 24 amino acids in plasma of foetuses were significantly higher, while four of 24 were lower, than their concentration in maternal plasma. The higher foetal concentrations of amino acids in plasma are similar to other species, with some exceptions, and suggest that equine placenta actively transports and concentrates amino acids into the umbilical circulation. Concentrations of nine of 24 amino acids were significantly lower in plasma from the umbilical artery compared to plasma from the umbilical vein, while no significant differences were present between maternal artery and vein plasma. The umbilical venous-arterial difference in concentrations of amino acids in plasma suggests the foetus extracts amino acids from the umbilical circulation for catabolism or protein synthesis, as in other species.

Effect of garlic on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled clinical trials.

PubMed

Sahebkar, Amirhossein; Serban, Corina; Ursoniu, Sorin; Banach, Maciej

2016-01-01

Garlic can play an essential role in the prevention of atherosclerosis, but the research addressing the effect of garlic on the concentration of lipoprotein(a) [Lp(a)] has not been fully demonstrated. The aim of this study was to assess the effect of garlic on plasma Lp(a) concentrations through systematic review of literature and meta-analysis of available randomized controlled trials. The literature search included SCOPUS, PubMed-Medline, ISI Web of Science, and Google Scholar databases up to March 10, 2015 to identify randomized controlled trials investigating the effect of garlic on plasma Lp(a) concentrations. Two independent reviewers extracted data on study characteristics, methods, and outcomes. Overall, the effect of garlic on plasma Lp(a) levels was reported in six trials. Meta-analysis did not suggest a significant alteration in plasma Lp(a) levels after garlic consumption (weighted mean difference [WMD] = 16.86%; 95% confidence interval, -4.59 to 38.31; P = 0.124). This result was robust in the leave-one-out sensitivity analysis. When the studies were categorized according to the duration of supplementation, there was no effect in the subgroup of trials lasting ≤12 wk (WMD = 2.01%; 95% CI, -14.67 to 18.68; P = 0.813) but a significant elevation of plasma Lp(a) concentrations was found in trials lasting >12 wk (WMD = 54.59%; 95% CI, 30.47-78.71; P < 0.001). Random-effects meta-regression suggested an inverse association between the changes in plasma concentrations of Lp(a) and duration of supplementation (slope 1.71; 95% CI, 0.46-2.97; P = 0.007). The present meta-analysis did not suggest a significant effect of garlic supplementation on the reduction of Lp(a) levels. Copyright © 2016 Elsevier Inc. All rights reserved.

Steady-state pharmacokinetics of (R)- and (S)-methadone in methadone maintenance patients

PubMed Central

Foster, David J R; Somogyi, Andrew A; Dyer, Kyle R; White, Jason M; Bochner, Felix

2000-01-01

Aims To investigate the steady-state pharmacokinetics of (R)- and (S)-methadone in a methadone maintenance population. Methods Eighteen patients recruited from a public methadone maintenance program underwent an interdosing interval pharmacokinetic study. Plasma and urine samples were collected and analysed for methadone and its major metabolite (EDDP) using stereoselective h.p.l.c. Methadone plasma protein binding was examined using ultrafiltration, and plasma α1-acid glycoprotein concentrations were quantified by radial immunoassay. Results (R)-methadone had a significantly (P < 0.05) greater unbound fraction (mean 173%) and total renal clearance (182%) compared with (S)-methadone, while maximum measured plasma concentrations (83%) and apparent partial clearance of methadone to EDDP (76%) were significantly (P < 0.001) lower. When protein binding was considered (R)-methadone plasma clearance of the unbound fraction (59%) and apparent partial intrinsic clearance to EDDP (44%) were significantly (P < 0.01) lower than for (S)-methadone, while AUCτSS, (167%) was significantly (P < 0.001) greater. There were no significant (P > 0.2) differences between the methadone enantiomers for AUCτSS, steady-state plasma clearance, trough plasma concentrations and unbound renal clearance. Patients excreted significantly (P < 0.0001) more (R)-methadone and (S)-EDDP than the corresponding enantiomers. Considerable interindividual variability was observed for the pharmacokinetic parameters, with coefficients of variation of up to 70%. Conclusions Steady-state pharmacokinetics of unbound methadone are stereoselective, and there is large interindividual variability consistent with CYP3A4 mediated metabolism to the major metabolite EDDP; the variability did not obscure a significant dose-plasma concentration relationship. Stereoselective differences in the pharmacokinetics of methadone may have important implications for pharmacokinetic-pharmacodynamic modelling but is unlikely to be important for therapeutic drug monitoring of methadone, in the setting of opioid dependence. PMID:11069437

Evaluation and routine application of the novel restricted-access precolumn packing material Alkyl-Diol Silica: coupled-column high-performance liquid chromatographic analysis of the photoreactive drug 8-methoxypsoralen in plasma.

PubMed

Vielhauer, S; Rudolphi, A; Boos, K S; Seidel, D

1995-04-21

A fully automated coupled-column HPLC method for on-line sample processing and determination of the photoreactive drug 8-methoxypsoralen (8-MOP) in plasma has been developed. The method is based on the novel internal-surface reversed-phase precolumn packing materials Alkyl-Diol Silica (ADS). This new family of restricted-access materials has a hydrophilic, electroneutral outer particle surface and a hydrophobic internal pore surface. The supports tolerate the direct and repetitive injection of proteinaceous fluids such as plasma and allow a classical C18-, C8- or C4-reversed-phase partitioning at the internal (pore) surface. The total protein load, i.e. the lifetime of the precolumn used in this study (C8-Alkyl-Diol Silica, 25 microns, 25 x 4 mm I.D.), exceeds more than 100 ml of plasma. 8-MOP was detected by its native fluorescence (excitation 312 nm, emission 540 nm). Validation of the method revealed a quantitative and matrix-independent recovery (99.5-101.3% measured at five concentrations between 21.3 and 625.2 ng of 8-MOP per milliliter of plasma), linearity over a wide range of 8-MOP concentrations (1.2-3070 ng of 8-MOP/ml, r = 0.999), low limits of detection (0.39 ng of 8-MOP/ml) and quantitation (0.79 ng of 8-MOP/ml) and a high between-run (C.V. 1.47%, n = 10) and within-run (C.V. 1.33%, n = 10) reproducibility. This paper introduces coupled-column HPLC as a suitable method for on-site analysis of drug plasma profiles (bedside-monitoring).

High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry in the positive and negative ionization modes.

PubMed

Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masae; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Seno, Hiroshi

2011-06-01

In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in the positive and negative ionization modes using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with Acquity UPLC BEH C(18) column and Acquity TQD tandem quadrupole mass spectrometer equipped with an electrospray ionization interface. The calibration curves for muscle relaxants spiked into human plasma equally showed good linearities in the nanogram per milliliter order range. The detection limits (signal-to-noise ratio = 3) was as low as 0.1-2 ng/mL. The method gave satisfactory recovery rates, accuracy, and precision for quality control samples spiked with muscle relaxants. To further validate the present method, 250 mg of chlorphenesin carbamate was orally administered to a healthy male volunteer, and the concentrations of chlorphenesin carbamate in plasma were measured 0.5, 1, 2, 4, 6, and 8 h after dosing; their concentrations in human plasma were between 0.62 and 2.44 μg/mL. To our knowledge, this is the first report describing simultaneous analysis of over more than two central-acting muscle relaxants by liquid chromatography-tandem mass spectrometry. This has been realized by the capability of our instrument for simultaneous multiple reaction monitoring of the target compounds in both positive and negative ionization modes. Therefore, the present method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

HPLC-MS/MS methods for the quantitative analysis of 5-oxoproline (pyroglutamate) in rat plasma and hepatic cell line culture medium.

PubMed

Geenen, Suzanne; Guallar-Hoyas, Cristina; Michopoulos, Filippos; Kenna, J Gerry; Kolaja, Kyle L; Westerhoff, Hans V; Thomas, Paul; Wilson, Ian D

2011-11-01

5-Oxoproline (5-OP; pyroglutamate) is an intermediate in the biosynthesis of the endogenous tripeptide glutathione and has been seen to be elevated in the biofluids and tissues of rats following the administration of glutathione-depleting hepatotoxic xenobiotics such as acetaminophen (paracetamol), bromobenzene and ethionine. As 5-OP is a potential biomarker for hepatotoxicity HPLC-MS/MS methods have been developed for its quantification in in vitro cell culture media and rat plasma. For the cell culture media the lower limit of quantification (LLOQ), defined as the lowest concentration on the calibration curve, was 10 ng/ml. Minimal carry over was observed for cell culture media between injections (less than 5% at all concentrations examined), precision and accuracy were generally better than 20% for within and between day analyses. For rat plasma a LLOQ of 50 ng/ml was obtained. Carry over for plasma was less than 5% for all concentrations, within and between batch accuracy and precision were generally better than 20%. The methods were linear for both sample types from the LLOQ up to 1 μg/ml. For samples obtained from rats subjected to chronic administration of the hepatotoxin methapyrilene, concentrations of 5-OP were not observed to increase significantly at any time point compared to controls. 5-OP was also determined in the culture media of human liver epithelial (THLE) cells transfected with cytochrome P450 2E1 (THLE-2E1). Following exposure of THLE-2E1 cells to acetaminophen, large increases in the concentrations of 5-OP were observed, which correlated with reduced cellular glutathione content and with cell toxicity. These results show that LC-MS/MS can be used to perform rapid, sensitive, and quantitative determination of 5-OP in vivo and in vitro and will enable additional investigations into the utility of 5-OP as a biomarker of liver drug-induced liver injury. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of PNU-248686A, a novel matrix metalloproteinase inhibitor, in human plasma by liquid chromatography-tandem mass spectrometry, following protein precipitation in the 96-well plate format.

PubMed

Frigerio, E; Cenacchi, V; James, C A

2003-02-14

A sensitive, specific and high-throughput analytical method for the quantitation of PNU-248686A (I), in human plasma has been developed. I, sodium (2R)-3-[[(4'-chloro(1,1'-biphenyl)-4-yl]sulfonyl]-2-hydroxy-2-[(phenylsulfanyl)methyl] propanoate, is an orally active matrix metalloproteinase (MMP) inhibitor developed for the treatment of solid tumors over-expressing MMPs. Concentrations of I, as free acid, were determined in human plasma by LC-MS-MS after plasma protein precipitation in the 96-well plate format. Aliquots of plasma (50 microl) were placed into the plates and 0.2 ml of methanol was added. The plates were shaken for 5 min and centrifuged at 1500 g for 10 min. Aliquots of 10 microl of the supernatants were then directly injected into the LC-MS-MS system. A Symmetry Shield C. column (50 x 2.1 mm, 3.5 microm) was used to perform the chromatographic analysis. The mobile phase was 5 mM ammonium formate buffer solution pH 5.0-acetonitrile (60:40. v/v) with a flow-rate of 0.3 ml/min. Retention time of I was about 1.2 min. Total cycle time was 2.5 min. MS detection used the Applied Biosystems-MDS Sciex API 3000 with TurbolonSpray interface and single reaction monitoring (461 --> 251 m/z transition) operated in negative ion mode. Calibration curves were constructed by plotting the area of the compound (y) against its concentration (x). A weighed linear regression (weighting factor 1/x(2)) was used to calculate I concentrations in quality control and unknown samples. The method was fully validated over the range of 5.0-5000 ng/ml. The suitability and robustness of the method for in vivo samples was confirmed by analysis of plasma samples from a pilot clinical study.

Estimation of the electric plasma membrane potential difference in yeast with fluorescent dyes: comparative study of methods.

PubMed

Peña, Antonio; Sánchez, Norma Silvia; Calahorra, Martha

2010-10-01

Different methods to estimate the plasma membrane potential difference (PMP) of yeast cells with fluorescent monitors were compared. The validity of the methods was tested by the fluorescence difference with or without glucose, and its decrease by the addition of 10 mM KCl. Low CaCl₂ concentrations avoid binding of the dye to the cell surface, and low CCCP concentrations avoid its accumulation by mitochondria. Lower concentrations of Ba²+ produce a similar effect as Ca²+, without producing the fluorescence changes derived from its transport. Fluorescence changes without considering binding of the dyes to the cells and accumulation by mitochondria are overshadowed by their distribution between this organelle and the cytoplasm. Other factors, such as yeast starvation, dye used, parameters of the fluorescence changes, as well as buffers and incubation times were analyzed. An additional approach to measure the actual or relative values of PMP, determining the accumulation of the dye, is presented.

Influence of uridine diphosphate glucuronosyltransferase 2B7 -161C>T polymorphism on the concentration of valproic acid in pediatric epilepsy patients.

PubMed

Inoue, Kazuyuki; Suzuki, Eri; Yazawa, Rei; Yamamoto, Yoshiaki; Takahashi, Toshiki; Takahashi, Yukitoshi; Imai, Katsumi; Koyama, Seiichi; Inoue, Yushi; Tsuji, Daiki; Hayashi, Hideki; Itoh, Kunihiko

2014-06-01

Valproic acid (VPA) is widely used to treat various types of epilepsy. Interindividual variability in VPA pharmacokinetics may arise from genetic polymorphisms of VPA-metabolizing enzymes. This study aimed to examine the relationships between plasma VPA concentrations and the -161C>T single nucleotide polymorphism in uridine diphosphate glucuronosyltransferase (UGT) 2B7 genes in pediatric epilepsy patients. This study included 78 pediatric epilepsy patients carrying the cytochrome P450 (CYP) 2C9*1/*1 genotype and who were not treated with the enzyme inducers (phenytoin, phenobarbital, and carbamazepine), lamotrigine, and/or topiramate. CYP2C9*3 and UGT2B7 -161C>T polymorphisms were identified using methods based on polymerase chain reaction-restriction fragment length polymorphism. Blood samples were drawn from each patient under steady-state conditions, and plasma VPA concentrations were measured. Significant differences in adjusted plasma VPA concentrations were observed between carriers of CC, CT, and TT genotypes in the UGT2B7 -161C>T polymorphism (P = 0.039). Patients with the CC genotype had lower adjusted plasma VPA concentrations than those with CT or TT genotype (P = 0.028). These data suggest that the UGT2B7 -161C>T polymorphism in pediatric epilepsy patients carrying the CYP2C9*1/*1 genotype affects VPA concentration.

A Study on Pharmacokinetics of Bosentan with Systems Modeling, Part 1: Translating Systemic Plasma Concentration to Liver Exposure in Healthy Subjects.

PubMed

Li, Rui; Niosi, Mark; Johnson, Nathaniel; Tess, David A; Kimoto, Emi; Lin, Jian; Yang, Xin; Riccardi, Keith A; Ryu, Sangwoo; El-Kattan, Ayman F; Maurer, Tristan S; Tremaine, Larry M; Di, Li

2018-04-01

Understanding liver exposure of hepatic transporter substrates in clinical studies is often critical, as it typically governs pharmacodynamics, drug-drug interactions, and toxicity for certain drugs. However, this is a challenging task since there is currently no easy method to directly measure drug concentration in the human liver. Using bosentan as an example, we demonstrate a new approach to estimate liver exposure based on observed systemic pharmacokinetics from clinical studies using physiologically based pharmacokinetic modeling. The prediction was verified to be both accurate and precise using sensitivity analysis. For bosentan, the predicted pseudo steady-state unbound liver-to-unbound systemic plasma concentration ratio was 34.9 (95% confidence interval: 4.2, 50). Drug-drug interaction (i.e., CYP3A and CYP2B6 induction) and inhibition of hepatic transporters (i.e., bile salt export pump, multidrug resistance-associated proteins, and sodium-taurocholate cotransporting polypeptide) were predicted based on the estimated unbound liver tissue or plasma concentrations. With further validation and refinement, we conclude that this approach may serve to predict human liver exposure and complement other methods involving tissue biopsy and imaging. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

A Method for Electrochemical Detection of Brain Derived Neurotrophic Factor (BDNF) in plasma.

PubMed

Bockaj, Marina; Fung, Barnabas; Tsoulis, Michael; Foster, Lauren Warren; Soleymani, Leyla

2018-06-22

Currently, a blood test for the diagnosis of endometriosis, a common estrogen-dependent gynecological disease, does not exist. Recent studies suggest that circulating concentrations of brain derived neurotrophic factor (BDNF) have potential for the diagnosis of endometriosis. However, at present BDNF can only be measured by ELISA which requires a clinic visit, a routine blood sample, and laboratory testing. Therefore, we developed a point-of-care device (EndoChip) for use with small blood volumes that can be collected through a finger prick. Specifically, the presented device is a polymer-based chip with a wrinkled nanoporous gold film acting as the electrode/sensing layer, allowing for the electrochemical detection of BDNF in plasma. Increasing concentrations of BDNF (0.25 - 2.0 ng/ml) induced significant differences in redox current. The biosensor produces a signal readout in a matter of seconds, and is ideal for realizing multiplexing. Blood samples were collected from women (n=20) with chronic pelvic pain undergoing a diagnostic laparoscopy. Plasma BDNF concentrations measured by commercial ELISA were positively correlated (r2=0.8216; p<0.001) with results from the EndoChip. Our results demonstrate a quick and reliable method for point-of-care quantification of circulating concentrations of BDNF and a promising diagnostic tool for endometriosis.

Plasma lactate concentration as a predictor of gastric necrosis and survival among dogs with gastric dilatation-volvulus: 102 cases (1995-1998).

PubMed

de Papp, E; Drobatz, K J; Hughes, D

1999-07-01

To determine relationships between plasma lactate concentration and gastric necrosis and between plasma lactate concentration and outcome for dogs with gastric dilatation-volvulus. Retrospective study. 102 dogs. Information on signalment, history, plasma lactate concentration, medical and surgical treatment, cost of hospitalization, and outcome was retrieved from medical records. 69 of 70 (99%) dogs with plasma lactate concentration < 6.0 mmol/L survived, compared with 18 of 31 (58%) dogs with plasma lactate concentration > 6.0 mmol/L (1 dog euthanatized for economic reasons was not included). Gastric necrosis was identified in 38 (37%) dogs. Median plasma lactate concentration in dogs with gastric necrosis (6.6 mmol/L) was significantly higher than concentration in dogs without gastric necrosis (3.3 mmol/L). Specificity and sensitivity of using plasma lactate concentration (with a cutoff of 6.0 mmol/L) to predict which dogs had gastric necrosis were 88 and 61%, respectively. Sixty-two of 63 (98%) dogs without gastric necrosis survived, compared with 25 of 38 (66%) dogs with gastric necrosis. Preoperative plasma lactate concentration was a good predictor of gastric necrosis and outcome for dogs with GDV. Preoperative measurement of plasma lactate concentration may assist in determining prognosis of dogs with GDV.

Analyzing silver concentration in soil using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Prasetyo, S.; Isnaeni; Zaitun; Mitchell, K.; Suliyanti, M. M.; Herbani, Y.

2018-03-01

Determination of concentration of heavy metal ions in soil, such as silver, is very important to study soil pollution levels. Several techniques have been developed to determine silver ion concentration in soil. In this paper, we utilized laser-induced breakdown spectroscopy (LIBS) to study silver concentration in soil. We used four different data analysis methods to calculate silver concentration. In this case, we prepared soil samples with different silver ion concentrations from 400 ppm to 1000 ppm. Our analysis was focused on the 843.15 nm silver atomic absorption line. We found that plasma intensity increased as silver concentration increased. Our findings were based on our analysis using four different analysis methods. We believe that these analysis methods are able to calculate silver concentration in soil using LIBS.

Do plasma melatonin concentrations decline with age?

NASA Technical Reports Server (NTRS)

Zeitzer, J. M.; Daniels, J. E.; Duffy, J. F.; Klerman, E. B.; Shanahan, T. L.; Dijk, D. J.; Czeisler, C. A.

1999-01-01

PURPOSE: Numerous reports that secretion of the putative sleep-promoting hormone melatonin declines with age have led to suggestions that melatonin replacement therapy be used to treat sleep problems in older patients. We sought to reassess whether the endogenous circadian rhythm of plasma melatonin concentration changes with age in healthy drug-free adults. METHODS: We analyzed the amplitude of plasma melatonin profiles during a constant routine in 34 healthy drug-free older subjects (20 women and 14 men, aged 65 to 81 years) and compared them with 98 healthy drug-free young men (aged 18 to 30 years). RESULTS: We could detect no significant difference between a healthy and drug-free group of older men and women as compared to one of young men in the endogenous circadian amplitude of the plasma melatonin rhythm, as described by mean 24-hour average melatonin concentration (70 pmol/liter vs 73 pmol/liter, P = 0.97), or the duration (9.3 hours vs 9.1 hours, P = 0.43), mean (162 pmol/liter vs 161 pmol/liter, P = 0.63), or integrated area (85,800 pmol x min/liter vs 86,700 pmol x min/liter, P = 0.66) of the nocturnal peak of plasma melatonin. CONCLUSION: These results do not support the hypothesis that reduction of plasma melatonin concentration is a general characteristic of healthy aging. Should melatonin replacement therapy or melatonin supplementation prove to be clinically useful, we recommend that an assessment of endogenous melatonin be carried out before such treatment is used in older patients.

Clinical Significance of Plasma Epstein-Barr Virus DNA in Pulmonary Lymphoepithelioma-like Carcinoma (LELC) Patients.

PubMed

Xie, Mian; Wu, Xiaojun; Wang, Fang; Zhang, Jinjun; Ben, Xiaosong; Zhang, Jiexia; Li, Xiaoxiang

2018-02-01

Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a histologically distinctive subtype of NSCLC and an Epstein-Barr virus (EBV)-associated epithelial neoplasm. We investigated the clinical significance of plasma concentrations of EBV DNA in patients with pulmonary LELC. Two independent sets of plasma samples from a total of 429 patients with patients with pulmonary LELC (287 initial and 142 confirmatory) were available for EBV DNA determination. Plasma samples from the patients were subjected to a real-time quantitative polymerase chain reaction before treatment and 3 months after radical resection. Cutoff points were determined for pretreatment plasma EBV DNA concentration (low <4000 copies/mL versus high ≥4000 copies/mL) on the basis of a measure of heterogeneity with the log-rank test statistic with respect to overall survival (OS). The Kaplan-Meier method and Cox regression were used to evaluate the relationship between plasma EBV DNA concentrations and clinical outcome. Among patients with advanced-stage pulmonary LELC who underwent sequential blood draws, we evaluated the relationship between change in disease status and change in EBV DNA concentrations by using nonparametric tests. High EBV DNA concentration was associated with shorter OS in the initial, confirmatory, and combined data sets (combined data set hazard ratio = 3.67, 95% confidence interval: 2.72-4.38, p < 0.001). These findings persisted after multivariable adjustment. Compared with low EBV DNA concentration, high EBV DNA concentration was associated with shorter OS in patients with any stage of disease. High EBV DNA concentration was also associated with shorter disease-free survival (DFS) in patients with stage I/II disease. Patients with persistently detectable plasma EBV DNA had significantly poorer OS (p < 0.001) and DFS (p < 0.001) than did patients with undetectable EBV DNA 3 months after radical resection. In patients who underwent sequential evaluation of EBV DNA, an association was identified between an increase in EBV DNA concentration and a poor response to treatment and disease progression of pulmonary LELC. High baseline EBV DNA concentration is an independent poor prognostic marker in patients with pulmonary LELC. These results should be confirmed in larger prospective trials. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Cadmium, Chromium, and Copper Concentration plus Semen-Quality in Environmental Pollution Site, China

PubMed Central

LI, Yan; GAO, Qiaoyan; LI, Mingcai; LI, Mengyang; GAO, Xueming

2014-01-01

Abstract Background The environmental pollution is one of the factors contributing to the decrease of sperm quality for human beings. The aim of this study was to assess cadmium (Cd), chromium (Cr), and copper (Cu) concentration of man in environmental pollution site, and explore relationships between men exposure to Cd, Cr, and Cu and semen-quality parameters in environmental pollution site. Methods Ninety five men were recruited through pollution area and controls in 2011. We measured semen quality using Computer-aided Semen Quality Analysis, and Cd, Cr, and Cu levels in seminal plasma using Graphite Gurnace Atomic Absorption Spectroscopy. Spearman rank correlation analysis was used to evaluate the correlation between Cd, Cr and Cu concentration in seminal plasma and semen quality. Results The mean of seminal plasma Cd, Cr, and Cu values in pollution area was higher than the controls. Seminal plasma Cr values displayed a significant negative correlation with total motility and normomorph sperm rate. Seminal plasma Cu values also displayed a negative correlation with normomorph sperm rate. Conclusions Male reproductive health may be threatened by environmental pollution, and it may be influence local population diathesis. PMID:26060677

Tree ring wood analysis after hydrogen peroxide pressure decomposition with inductively coupled plasma atomic emission spectrometry and electrothermal vaporization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matusiewicz, H.; Barnes, R.M.

1985-02-01

A method utilizing pressure decomposition to minimize sample pretreatment is described for the inductively coupled plasma atomic emission spectrometric analysis of red spruce and sugar maple. Cores collected from trees growing on Camels Hump Mountain, Vermont, were divided into decade increments in order to monitor the temporal changes in concentrations of 21 elements. Dried wood samples were decomposed in a bomb made of Teflon with 50% hydrogen peroxide heated in an oven at 125/sup 0/C for 4 h. The digestion permitted use of aqueous standards and minimized any potential matrix effects. The element concentrations were obtained sequentially by electrothermal vaporizationmore » ICP-AES using 5 ..mu..L sample aliquots. The method precision varied between 3 and 12%. Elements forming oxyanions (Al, As, Fe, Ge, Mn, Si, V) were found at elevated concentrations during the most recent three decades, while other metal (e.g., Mg, Zn) concentrations were unchanged or decreased. 45 references, 6 tables, 1 figure.« less

Solid lipid nanoparticles delivering anti-inflammatory drugs to treat inflammatory bowel disease: Effects in an in vivo model

PubMed Central

Dianzani, Chiara; Foglietta, Federica; Ferrara, Benedetta; Rosa, Arianna Carolina; Muntoni, Elisabetta; Gasco, Paolo; Della Pepa, Carlo; Canaparo, Roberto; Serpe, Loredana

2017-01-01

AIM To improve anti-inflammatory activity while reducing drug doses, we developed a nanoformulation carrying dexamethasone and butyrate. METHODS Dexamethasone cholesteryl butyrate-solid lipid nanoparticles (DxCb-SLN) were obtained with the warm microemulsion method. The anti-inflammatory activity of this novel nanoformulation has been investigated in vitro (cell adhesion to human vascular endothelial cells and pro-inflammatory cytokine release by lipopolysaccharide-induced polymorphonuclear cells) and in vivo (disease activity index and cytokine plasma concentrations in a dextran sulfate sodium-induced mouse colitis) models. Each drug was also administered separately to compare its effects with those induced by their co-administration in SLN at the same concentrations. RESULTS DxCb-SLN at the lowest concentration tested (Dx 2.5 nmol/L and Cb 0.1 μmol/L) were able to exert a more than additive effect compared to the sum of the individual effects of each drug, inducing a significant in vitro inhibition of cell adhesion and a significant decrease of pro-inflammatory cytokine (IL-1β and TNF-α) in both in vitro and in vivo models. Notably, only the DxCb nanoformulation administration was able to achieve a significant cytokine decrease compared to the cytokine plasma concentration of the untreated mice with dextran sulfate sodium-induced colitis. Specifically, DxCb-SLN induced a IL-1β plasma concentration of 61.77% ± 3.19%, whereas Dx or Cb used separately induced a concentration of 90.0% ± 2.8% and 91.40% ± 7.5%, respectively; DxCb-SLN induced a TNF-α plasma concentration of 30.8% ± 8.9%, whereas Dx or Cb used separately induced ones of 99.5% ± 4.9% and 71.1% ± 10.9%, respectively. CONCLUSION Our results indicate that the co-administration of dexamethasone and butyrate by nanoparticles may be beneficial for inflammatory bowel disease treatment. PMID:28694660

The Association Between Calcium, Magnesium, and Ratio of Calcium/Magnesium in Seminal Plasma and Sperm Quality.

PubMed

Liang, Hong; Miao, Maohua; Chen, Jianping; Chen, Kanglian; Wu, Bin; Dai, Qi; Wang, Jian; Sun, Fei; Shi, Huijuan; Yuan, Wei

2016-11-01

The study aimed to examine the relationships between calcium, magnesium, and calcium/magnesium ratio in semen plasma and sperm quality. It was a cross-sectional study based on a program aiming at promoting the reproductive health in less-developed areas. A total of 515 men aged between 18 and 55 years provided semen specimens at family planning clinics in Sandu County, Guizhou Province, China. Total calcium and magnesium concentrations in semen plasma were measured with flame atomic absorption spectrometry. Sperm quality, including sperm motility and concentration, was evaluated by using a computer-assisted sperm analysis method. The medians of seminal plasma calcium, magnesium, and zinc concentrations were 9.61, 4.41, and 2.23 mmol/l, respectively. Calcium concentration and calcium/magnesium ratio were negatively associated with sperm concentrations (β = -0.47, P = 0.0123 for calcium; β = -0.25, P = 0.0393 for calcium/magnesium ratio) after adjusting for zinc and other covariates. In stratified analyses, the association between calcium and sperm concentrations only persisted among subjects with a calcium/magnesium ratio of ≤2.5 (β = -0.71, P = 0.0268). In the same stratum, magnesium was associated with increased sperm concentration (β = 0.73, P = 0.0386). Among subjects with a calcium/magnesium ratio of >2.5, neither calcium nor magnesium was associated with sperm concentration. In conclusion, total calcium and magnesium concentrations were associated with sperm concentration among subjects with a lower calcium/magnesium ratio. The calcium and magnesium ratio had a modifying effect on the associations of calcium and magnesium with sperm concentration.

Determination of flurbiprofen in human plasma by gas chromatography with mass spectrometry and its pharmacokinetics.

PubMed

Yilmaz, Bilal; Sahin, Huseyin; Akba, Vedat; Erdem, Ali Fuat

2014-01-01

This paper describes a GCIMS method for the determination of flurbiprofen in human plasma. Flurbiprofen and internal standard ibuprofen were extracted from plasma by using a liquid-liquid extraction method. Derivatization was carried out using N-Methyl-N-(trimethylsilyl)trifluoroacetamide. The calibration curve was linear between the concentration range of 0.10 and 5.0 microg/mL. Intraday and interday precision values for flurbiprofen in plasma were less than 5.49%, and accuracy (relative error) was better than 5.33%. The extraction recoveries of flurbiprofen from human plasma were between 93.6 and 98.6%. The LOD and LOQ of flurbiprofen were 0.03 and 0.10 microg/mL, respectively. This assay was applied to determine the pharmacokinetic parameters of flurbiprofen in healthy Turkish volunteers who had been given 100 mg of flurbiprofen.

LC-MS/MS method for the determination of haemanthamine in rat plasma, bile and urine and its application to a pilot pharmacokinetic study.

PubMed

Hroch, Miloš; Mičuda, Stanislav; Havelek, Radim; Cermanová, Jolana; Cahlíková, Lucie; Hošťálková, Anna; Hulcová, Daniela; Řezáčová, Martina

2016-07-01

Evidence gathered in various studies points to the fact that haemanthamine, an isoquinoline alkaloid, has multiple medicinally interesting characteristics, including antitumor, antileukemic, antioxidant, antiviral, anticonvulsant and antimalarial activity. This work presents, for the first time, a universal LC-MS/MS method for analysis of haemanthamine in plasma, bile and urine which has been verified in a pilot pharmacokinetic experiment on rats. Chromatographic separation was performed on a pentafluorophenyl core-shell column in gradient elution mode with a mobile phase consisting of acetonitrile-methanol-ammonium formate buffer. A sample preparation based on liquid-liquid extraction with methyl tert-butyl ether was employed with ambelline used as an internal standard. Quantification was performed using LC-MS-ESI(+) in Selected Reaction Monitoring mode. The method was validated according to the European Medicines Agency guideline in a concentration range of 0.1-10 μmol/L in plasma, bile and urine. The concentration-time profiles of haemanthamine in plasma, bile and urine after a single i.v. bolus of 10 mg/kg have been described for the first time. The presented study addresses the lack of information on haemanthamine pharmacokinetics and also introduces a new universal method of haemanthamine analysis in complex biological matrices. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Phenytoin kinetics during pregnancy and the puerperium.

PubMed

Knott, C; Williams, C P; Reynolds, F

1986-10-01

During pregnancy changes in maternal physiology and plasma composition may alter drug binding and dose requirements. We have measured plasma unbound and total phenytoin, and saliva concentrations at intervals in 11 pregnant epileptics. Plasma albumin concentrations were also measured in pregnant and non-pregnant women. Saliva phenytoin correlated closely with the plasma unbound concentrations (r = 0.98). The saliva:plasma (S:P) ratio, reflecting the free fraction, was variable during pregnancy but tended to increase to maximal values at delivery and return to non-pregnant values within 2-8 weeks thereafter. Plasma albumin concentrations correlated poorly with phenytoin binding. Binding in umbilical cord plasma appeared higher than that in maternal plasma and total fetal concentrations correlated closely with maternal plasma concentrations at delivery. No ill effects of phenytoin were detected in the newborn infant. During the third trimester phenytoin dose increments were necessary to maintain therapeutic concentrations. After delivery maternal saliva phenytoin concentrations rose, and dose reductions were necessary to avoid clinical symptoms of toxicity. It is therefore appropriate to monitor saliva phenytoin concentrations regularly both during pregnancy and the puerperium.

Validation of a liquid chromatography-triple quadrupole mass spectrometric method for the determination of 5-nitro-5'-hydroxy-indirubin-3'-oxime (AGM-130) in human plasma and its application to microdose clinical trial.

PubMed

Park, Min-Ho; Lee, Yun Young; Cho, Kyung Hee; La, Sookie; Lee, Hee Joo; Yim, Dong-Seok; Ban, Sooho; Park, Moon-Young; Kim, Yong-Chul; Kim, Yoon-Gyoon; Shin, Young G

2016-03-01

A liquid chromatography-triple quadrupole mass spectrometric (LC-MS/MS) method was developed and validated for the determination of 5-nitro-5'-hydroxy-indirubin-3'-oxime (AGM-130) in human plasma to support a microdose clinical trial. The method consisted of a liquid-liquid extraction for sample preparation and LC-MS/MS analysis in the positive ion mode using TurboIonSpray(TM) for analysis. d3 -AGM-130 was used as the internal standard. A linear regression (weighted 1/concentration) was used to fit calibration curves over the concentration range of 10-2000 pg/mL for AGM-130. There were no endogenous interference components in the blank human plasma tested. The accuracy at the lower limit of quantitation was 96.6% with a precision (coefficient of variation, CV) of 4.4%. For quality control samples at 30, 160 and 1600 pg/mL, the between run CV was ≤5.0 %. Between-run accuracy ranged from 98.1 to 101.0%. AGM-130 was stable in 50% acetonitrile for 168 h at 4°C and 6 h at room temperature. AGM-130 was also stable in human plasma at room temperature for 6 h and through three freeze-thaw cycles. The variability of selected samples for the incurred sample reanalysis was ≤12.7% when compared with the original sample concentrations. This validated LC-MS/MS method for determination of AGM-130 was used to support a phase 0 microdose clinical trial. Copyright © 2015 John Wiley & Sons, Ltd.

Pharmacokinetics of sarizotan after oral administration of single and repeat doses in healthy subjects.

PubMed

Krösser, S; Tillner, J; Fluck, M; Ungethüm, W; Wolna, P; Kovar, A

2007-05-01

Sarizotan is a 5-HTIA receptor agonist with high affinity for D3 and D4 receptors. Here we report the pharmacokinetic and tolerability results from four Phase 1 studies. Two single-dose (5 -25 mg, n = 25, 0.5 - 5 mg, n = 16) and two multiple-dose (10 and 20 mg b.i.d., n = 30, 5 mg b.i.d., n = 12) studies with orally administered sarizotan HCl were carried out in healthy subjects. Plasma sarizotan HCl concentrations were measured using a validated HPLC method and fluorescence or MS/MS detection. Pharmacokinetic parameters were obtained using standard non-compartmental methods. Sarizotan was rapidly absorbed, group-median times to reach maximum concentration (tmax) ranged from 0.5 -2.25 h after single doses and during steady state. Maximum plasma concentration (Cmax) and tmax were slightly dependent on formulation and food intake, whereas area under the curve (AUC) was unaffected by these factors. AUC and Cmax increased dose-proportionally over the tested dose range. Independently of dose and time, sarizotan HCl plasma concentrations declined polyexponentially with a terminal elimination half-life (t1/2) of 5 - 7 h. Accumulation factors corresponded to t1/2 values, and steady state was reached within 24 h. Plasma metabolite concentrations were considerably lower than those of the parent drug. The ratio metabolite AUC : parent drug AUC was time- and dose-independent for all three metabolites suggesting that the metabolism of sarizotan is non-saturable in the tested dose range. The pharmacokinetics of sarizotan were dose-proportional and time-independent for the dose range 0.5 -25 mg). The drug was well-tolerated by healthy subjects up to a single dose of 20 mg.

A rapid quantitative analysis of bile acids, lysophosphatidylcholines and polyunsaturated fatty acids in biofluids based on ultraperformance liquid chromatography coupled with triple quadrupole tandem massspectrometry.

PubMed

Peng, Zhangxiao; Zhang, Qian; Mao, Ziming; Wang, Jie; Liu, Chunying; Lin, Xuejing; Li, Xin; Ji, Weidan; Fan, Jianhui; Wang, Maorong; Su, Changqing

2017-11-15

Much evidence suggested that quantitative analysis of bile acids (BAs), lysophosphatidylcholines (LPCs), and polyunsaturated fatty acids (PUFAs) in biofluids may be very useful for diagnosis and prevention of hepatobiliary disease with a non-invasive manner. However, simultaneously fast analysis of these metabolites has been challenging for their huge differences of physicochemical properties and concentration levels in biofluids. In this study, we present a liquid chromatography-mass spectrometry method with a high throughput analytical cycle (10min) to fast and accurately quantify fifteen potential biomarkers (eight BAs, four LPCs and three PUFAs) of hepatobiliary disease. The accuracy for the fifteen analytes in plasma and urine matrices was 80.45%-118.99% and 84.55%-112.66%, respectively. The intra- and inter- precisions for the fifteen analytes in plasma and urine matrices were all less than 20% and the lower limit of quantification (LLOQ) of analytes is up to 0.0283-8.2172nmol/L. Therefore, this method is fast, sensitive and accurate for the quantitative analysis of BAs, LPCs and PUFAs in biofluids. Moreover, the stability and concentration differences of the analytes in plasma and serum were evaluated, and the results demonstrated that LPCs is stable, but PUFAs is very unstable in freeze and thaw cycles, and the concentrations of the analytes in serum were slightly higher than those in plasma. We suggested plasma may be a kind of better bio-sample than serum using for quantitative analysis of metabolites in blood, due to the characteristics of plasma are more close to blood than those of serum. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrochemical characterization of repaglinide and its determination in human plasma using liquid chromatography with dual-channel coulometric detection.

PubMed

Jirovský, David; Bartošová, Zdenka; Skopalová, Jana; Maier, Vítezslav

2010-12-01

A simple, fast and sensitive HPLC method employing dual-channel coulometric detection for the determination of repaglinide in human plasma is presented. The assay involved extraction of repaglinide by ethyl acetate and isocratic reversed-phase liquid chromatography with dual-channel coulometric detection. The mobile phase composition was 50mM disodium hydrogen phosphate/acetonitrile (60:40, v/v), pH of the mobile phase 7.5 set up with phosphoric acid. For all analyses, the first cell working potential was +380mV, the second was +750mV (vs. Pd/H(2)). Calibration curve was linear over the concentration range of 5-500nmolL(-1). Rosiglitazone was used as an internal standard. The limit of detection (LOD) was established at 2.8nmolL(-1), and the lower limit of quantification (LLOQ) at 8.5nmolL(-1). The developed method was applied to human plasma samples spiked with repaglinide at therapeutical concentrations. It was confirmed that the method is suitable for pharmacokinetic studies or therapeutic monitoring. Copyright © 2010 Elsevier B.V. All rights reserved.

Studies of Be migration in the JET tokamak using AMS with 10Be marker

NASA Astrophysics Data System (ADS)

Bykov, I.; Bergsåker, H.; Possnert, G.; Zhou, Y.; Heinola, K.; Pettersson, J.; Conroy, S.; Likonen, J.; Petersson, P.; Widdowson, A.

2016-03-01

The JET tokamak is operated with beryllium limiter tiles in the main chamber and tungsten coated carbon fiber composite tiles and solid W tiles in the divertor. One important issue is how wall materials are migrating during plasma operation. To study beryllium redistribution in the main chamber and in the divertor, a 10Be enriched limiter tile was installed prior to plasma operations in 2011-2012. Methods to take surface samples have been developed, an abrasive method for bulk Be tiles in the main chamber, which permits reuse of the tiles, and leaching with hot HCl to remove all Be deposited at W coated surfaces in the divertor. Quantitative analysis of the total amount of Be in cm2 sized samples was made with inductively coupled plasma atomic emission spectroscopy (ICP-AES). The 10Be/9Be ratio in the samples was measured with accelerator mass spectrometry (AMS). The experimental setup and methods are described in detail, including sample preparation, measures to eliminate contributions in AMS from the 10B isobar, possible activation due to plasma generated neutrons and effects of diffusive isotope mixing. For the first time marker concentrations are measured in the divertor deposits. They are in the range 0.4-1.2% of the source concentration, with moderate poloidal variation.

Ultra-sensitive LC-MS/MS method for the quantification of gemcitabine and its metabolite 2',2'-difluorodeoxyuridine in human plasma for a microdose clinical trial.

PubMed

van Nuland, M; Hillebrand, M J X; Rosing, H; Burgers, J A; Schellens, J H M; Beijnen, J H

2018-03-20

In microdose clinical trials a maximum of 100 μg of drug substance is administered to participants, in order to determine the pharmacokinetic properties of the agents. Measuring low plasma concentrations after administration of a microdose is challenging and requires the use of ulta-sensitive equipment. Novel liquid chromatography-mass spectrometry (LC-MS/MS) platforms can be used for quantification of low drug plasma levels. Here we describe the development and validation of an LC-MS/MS method for quantification of gemcitabine and its metabolite 2',2'-difluorodeoxyuridine (dFdU) in the low picogram per milliliter range to support a microdose trial. The validated assay ranges from 2.5-500 pg/mL for gemcitabine and 250-50,000 pg/mL for dFdU were linear, with a correlation coefficient (r 2 ) of 0.996 or better. Sample preparation with solid phase extraction provided a good and reproducible recovery. All results were within the acceptance criteria of the latest US FDA guidance and EMA guidelines. In addition, the method was successfully applied to measure plasma concentrations of gemcitabine in a patient after administration of a microdose of gemcitabine. Copyright © 2017 Elsevier B.V. All rights reserved.

A simple, rapid and stability indicating validated method for quantification of lamotrigine in human plasma and dry plasma spot using LC-ESI-MS/MS: Application in clinical study.

PubMed

Namdev, Kuldeep Kumar; Dwivedi, Jaya; Chilkoti, Deepak Chandra; Sharma, Swapnil

2018-01-01

Lamotrigine (LTZ) is a phenyltriazine derivative which belongs to anti-epileptic drugs (AEDs) class and prescribed as mono- or adjunctive-therapy in treatment of epilepsy. Therapeutic drug monitoring (TDM) of AEDs provides a valid clinical tool in optimization of overall therapy. However, TDM is challenging due to the high biological samples (plasma/blood) storage/shipment costs and the limited availability of laboratories providing TDM services. Sampling in the form of dry plasma spot (DPS) or dry blood spot (DBS) are suitable alternative to overcome these issues. We developed and validated a new method for quantification of LTZ in human plasma and DPS. The extraction of LTZ from plasma and DPS was performed using liquid-liquid extraction with diethyl ether and an extraction solution composed of diethyl ether- methyl tert-butyl ether- acetone (50:30:20, v/v/v), respectively. Lamotrigine- 13C3, d3 was used as internal standard (ISTD) and the chromatographic separation was achieved on Hypurity Advance C18 column (150×4.6mm, 5μm). Quantitative estimation of LTZ and ISTD was performed on a liquid chromatography tandem mass spectrometer coupled with electrospray ionization interface operated under positive mode of ionization. Calibration curves were linear (r 2 >0.99) over the concentration range of 10-3020ng/mL for both plasma and DPS. Statistical analysis provides insignificant difference between LTZ concentration extracted from plasma and DPS samples. The method is found suitable for application in clinical study and in therapeutic monitoring of LTZ. To the best of our knowledge this is the first report which describing a validated stability indicating assay for quantification of LTZ in dry plasma spot. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous measurement of proguanil and its metabolites in human plasma and urine by reversed-phase high-performance liquid chromatography, and its preliminary application in relation to genetically determined S-mephenytoin 4'-hydroxylation status.

PubMed

Kusaka, M; Setiabudy, R; Chiba, K; Ishizaki, T

1996-02-01

A simple high-performance liquid chromatographic (HPLC) assay method was developed for the measurement of proguanil (PG) and its major metabolites, cycloguanil (CG) and 4-chlorophenyl-biguanide (CPB), in human plasma and urine. The assay allowed the simultaneous determination of all analytes in 1 ml of plasma or 0.1 ml of urine. The detection limits of PG, CG, and CPB, defined as the signal-to-noise ratio of 3, were 1 and 5 ng/ml for plasma and urine samples, respectively. Recoveries of the analytes and the internal standard (pyrimethamine) were > 62% from plasma and > 77% from urine. Intra-assay and interassay coefficients of variation for all analytes in plasma and urine were < 10% except for the values of CG and CPB, which ranged from 10% to 15% at one or two concentrations among 4-5 concentrations studied. The clinical applicability of the method was assessed by the preliminary pharmacokinetic study of PG, CG, and CPB in six healthy volunteers with the individually known phenotypes (extensive and poor metabolizers) of S-mephenytoin 4'-hydroxylation, suggesting that individuals with a poor metabolizer phenotype of S-mephenytoin have a much lower capacity to bioactivate PG to CG compared with the extensive metabolizers.

Simultaneous determination of paclitaxel and a new P-glycoprotein inhibitor HM-30181 in rat plasma by liquid chromatography with tandem mass spectrometry.

PubMed

Paek, In Bok; Ji, Hye Young; Kim, Maeng Seop; Lee, Gwan Sun; Lee, Hye Suk

2006-03-01

An LC-MS/MS method for the simultaneous determination of a new P-glycoprotein inhibitor 4-oxo-4H-chromene-2-carboxylic acid [2-(2-(4-[2-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-ethyl]-phenyl)-2H-tetrazol-5-yl)-4,5-dimethoxy-phenyl]-amide (HM-30181) and a P-glycoprotein substrate paclitaxel in rat plasma was developed to simultaneously evaluate the pharmacokinetics of paclitaxel and HM-30181 in the rats. HM-30181, paclitaxel, HM-30059 (internal standard (I.S.) for HM-30181), and docetaxel (I.S. for paclitaxel) were extracted from rat plasma with methyl-tert-butyl ether and analyzed on an Atlantis C18 column (5 microm, 2.1 x 100 mm) with the mobile phase of ACN/10 mM ammonium formate (75:25 v/v). The analytes were detected using an ESI MS/MS in the multiple reaction monitoring (MRM) mode. The standard curves for HM-30181 and paclitaxel in plasma were linear (r > 0.999) over the concentration range of 2.0-500 ng/mL with a weighting of 1/concentration2. The method showed a satisfactory sensitivity (2 ng/mL using 50 microL plasma), precision (CV: < or = 6.6%), accuracy (relative error: -6.3 to 2.0%), and selectivity. This method was successfully applied to the pharmacokinetic study of HM-30181 and paclitaxel in rat plasma after oral-coadministration of paclitaxel and HM-30181 to male Sprague- Dawley rats.

Evaluating the relationship between plasma and skin carotenoids and reported dietary intake in elementary school children to assess fruit and vegetable intake

USDA-ARS?s Scientific Manuscript database

Accurate assessment of dietary intake of children can be challenging due to the limited reliability of current dietary assessment methods in children. While plasma carotenoid concentrations has been used to assess fruit and vegetable intake, this testing is rarely conducted in school settings in chi...

N-acetyltransferase gene polymorphisms & plasma isoniazid concentrations in patients with tuberculosis.

PubMed

Hemanth Kumar, A K; Ramesh, K; Kannan, T; Sudha, V; Haribabu, Hemalatha; Lavanya, J; Swaminathan, Soumya; Ramachandran, Geetha

2017-01-01

Variations in the N-acetyltransferase (NAT2) gene among different populations could affect the metabolism and disposition of isoniazid (INH). This study was performed to genotype NAT2 gene polymorphisms in tuberculosis (TB) patients from Chennai, India, and compare plasma INH concentrations among the different genotypes. Adult patients with TB treated in the Revised National TB Control Programme (RNTCP) in Chennai, Tamil Nadu, were genotyped for NAT2 gene polymorphism, and two-hour post-dosing INH concentrations were compared between the different genotypes. Plasma INH was determined by high-performance liquid chromatography. Genotyping of the NAT2 gene polymorphism was performed by real-time polymerase chain reaction method. Among the 326 patients genotyped, there were 189 (58%), 114 (35%) and 23 (7%) slow, intermediate and fast acetylators, respectively. The median two-hour INH concentrations in slow, intermediate and fast acetylators were 10.2, 8.1 and 4.1 μg/ml, respectively. The differences in INH concentrations among the three genotypes were significant (P<0.001). Genotyping of TB patients from south India for NAT2 gene polymorphism revealed that 58 per cent of the study population comprised slow acetylators. Two-hour INH concentrations differed significantly among the three genotypes.

Prospective screening for occult cardiomyopathy in dogs by measurement of plasma atrial natriuretic peptide, B-type natriuretic peptide, and cardiac troponin-I concentrations.

PubMed

Oyama, Mark A; Sisson, D David; Solter, Phil F

2007-01-01

To evaluate the use of measuring plasma concentrations of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), and cardiac troponin-I (cTnI) to detect dogs with occult dilated cardiomyopathy (DCM). 118 client-owned dogs. Dogs were prospectively examined by use of ECG; echocardiography; and evaluation of concentrations of ANP, BNP, and cTnI. Occult DCM was diagnosed by evaluation of echocardiographic left ventricular dimensions and detection of ventricular arrhythmias on ECG. Sensitivity and specificity of assays for measurement of plasma concentrations of ANP, BNP, and cTnI to detect dogs with occult DCM were determined. Occult DCM was diagnosed in 21 dogs. A concentration of > 6.21 pg/mL for BNP had a sensitivity of 95.2% and specificity of 61.9% for identifying dogs with occult DCM. In contrast, concentrations of ANP and cTnI had relatively low predictive values. Blood-based screening for occult DCM in dogs can be accomplished by use of a BNP assay. Additional studies should be performed to optimize this method of screening dogs to detect occult DCM.

Plasma ascorbic acid concentrations in prevalent patients with end-stage renal disease on hemodialysis.

PubMed

Sirover, William D; Liu, Yuguan; Logan, Amanda; Hunter, Krystal; Benz, Robert L; Prasad, Deepali; Avila, Jose; Venkatchalam, Thaliga; Weisberg, Lawrence S; Handelman, Garry J

2015-05-01

To determine the prevalence of vitamin C (ascorbic acid [AA]) deficiency in patients with end-stage renal disease, the effect of supplemental AA on plasma AA concentrations, and the extrinsic and intrinsic factors that affect plasma AA concentrations in this patient population. In study 1, we compared the effect of hemodialysis (HD) on plasma AA concentrations between patients with low and high pre-HD AA concentrations. In study 2, we analyzed kinetic and nonkinetic factors for their association with increased plasma AA concentrations in patients on maintenance HD. Study 1 was performed in a single outpatient HD clinic in Cherry Hill, New Jersey. Study 2 was performed in 4 outpatient HD clinics in Southern New Jersey. In study 1, we collected plasma samples from 8 adult patients on maintenance HD at various time points around their HD treatment and assayed them for AA concentration. In study 2, we enrolled 203 adult patients and measured pre-HD plasma AA concentrations. We ascertained supplemental AA use and assessed dietary AA intake. In study 1, plasma AA concentrations were compared during the intradialytic and interdialytic period. In study 2, pre-HD plasma AA concentrations were correlated with supplement use and demographic factors. Study 1 showed that over the course of a single HD treatment, the plasma AA concentration decreased by a mean (±standard deviation) of 60% (±6.6). In study 2, the median pre-HD plasma AA concentration was 15.7 μM (interquartile range, 8.7-66.8) in patients who did not take a supplement and 50.6 μM (interquartile range, 25.1-88.8) in patients who did take a supplement (P < .001). Supplement use, increasing age, and diabetes mellitus were associated with a pre-HD plasma AA concentration ≥30 μM. HD depletes plasma AA concentrations, and AA supplementation allows patients to achieve higher plasma AA concentrations. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Analysis of 6-mercaptopurine in human plasma with a high-performance liquid chromatographic method including post-column derivatization and fluorimetric detection.

PubMed

Jonkers, R E; Oosterhuis, B; ten Berge, R J; van Boxtel, C J

1982-12-10

A relatively simple assay with improved reliability and sensitivity for measuring levels of 6-mercaptopurine in human plasma is presented. After extraction of the compound and the added internal standard with phenyl mercury acetate, samples were separated by ion-pair reversed-phase high-performance liquid chromatography. On-line the analytes were oxidized to fluorescent products and detected in a flow-fluorimeter. The within-day coefficient of variation was 3.8% at a concentration of 25 ng/ml. The lower detection limit was 2 ng/ml when 1.0 ml of plasma was used. Mercaptopurine concentration versus time curves of two subjects after a single oral dose of azathioprine are shown.

New evidence that a large proportion of human blood plasma cell-free DNA is localized in exosomes

PubMed Central

Jiang, Chao; Krzyzanowski, Gary D.; Ryan, Wayne L.

2017-01-01

Cell-free DNA (cfDNA) in blood is used as a source of genetic material for noninvasive prenatal and cancer diagnostic assays in clinical practice. Recently we have started a project for new biomarker discovery with a view to developing new noninvasive diagnostic assays. While reviewing literature, it was found that exosomes may be a rich source of biomarkers, because exosomes play an important role in human health and disease. While characterizing exosomes found in human blood plasma, we observed the presence of cfDNA in plasma exosomes. Plasma was obtained from blood drawn into K3EDTA tubes. Exosomes were isolated from cell-free plasma using a commercially available kit. Sizing and enumeration of exosomes were done using electron microscopy and NanoSight particle counter. NanoSight and confocal microscopy was used to demonstrate the association between dsDNA and exosomes. DNA extracted from plasma and exosomes was measured by a fluorometric method and a droplet digital PCR (ddPCR) method. Size of extracellular vesicles isolated from plasma was heterogeneous and showed a mean value of 92.6 nm and a mode 39.7 nm. A large proportion of extracellular vesicles isolated from plasma were identified as exosomes using a fluorescence probe specific for exosomes and three protein markers, Hsp70, CD9 and CD63, that are commonly used to identify exosome fraction. Fluorescence dye that stain dsDNA showed the association between exosomes and dsDNA. Plasma cfDNA concentration analysis showed more than 93% of amplifiable cfDNA in plasma is located in plasma exosomes. Storage of a blood sample showed significant increases in exosome count and exosome DNA concentration. This study provide evidence that a large proportion of plasma cfDNA is localized in exosomes. Exosome release from cells is a metabolic energy dependent process, thus suggesting active release of cfDNA from cells as a source of cfDNA in plasma. PMID:28850588

New evidence that a large proportion of human blood plasma cell-free DNA is localized in exosomes.

PubMed

Fernando, M Rohan; Jiang, Chao; Krzyzanowski, Gary D; Ryan, Wayne L

2017-01-01

Cell-free DNA (cfDNA) in blood is used as a source of genetic material for noninvasive prenatal and cancer diagnostic assays in clinical practice. Recently we have started a project for new biomarker discovery with a view to developing new noninvasive diagnostic assays. While reviewing literature, it was found that exosomes may be a rich source of biomarkers, because exosomes play an important role in human health and disease. While characterizing exosomes found in human blood plasma, we observed the presence of cfDNA in plasma exosomes. Plasma was obtained from blood drawn into K3EDTA tubes. Exosomes were isolated from cell-free plasma using a commercially available kit. Sizing and enumeration of exosomes were done using electron microscopy and NanoSight particle counter. NanoSight and confocal microscopy was used to demonstrate the association between dsDNA and exosomes. DNA extracted from plasma and exosomes was measured by a fluorometric method and a droplet digital PCR (ddPCR) method. Size of extracellular vesicles isolated from plasma was heterogeneous and showed a mean value of 92.6 nm and a mode 39.7 nm. A large proportion of extracellular vesicles isolated from plasma were identified as exosomes using a fluorescence probe specific for exosomes and three protein markers, Hsp70, CD9 and CD63, that are commonly used to identify exosome fraction. Fluorescence dye that stain dsDNA showed the association between exosomes and dsDNA. Plasma cfDNA concentration analysis showed more than 93% of amplifiable cfDNA in plasma is located in plasma exosomes. Storage of a blood sample showed significant increases in exosome count and exosome DNA concentration. This study provide evidence that a large proportion of plasma cfDNA is localized in exosomes. Exosome release from cells is a metabolic energy dependent process, thus suggesting active release of cfDNA from cells as a source of cfDNA in plasma.

Relationship between the von Willebrand Factor Plasma Concentration and Ultrasonographic Doppler Findings in Pregnancies Complicated by Hypertensive Disorders: A Pilot Study.

PubMed

Szpera-Gozdziewicz, Agata; Gozdziewicz, Tomasz; Boruczkowski, Maciej; Dworacki, Grzegorz; Breborowicz, Grzegorz H

2018-01-01

Recent evidence suggests that impaired cytotrophoblast proliferation and migration are major factors responsible for the development of hypertension in pregnancy. Studies report that von Willebrand factor (vWf) is a specific endothelial damage plasma marker. The aim of this study was to evaluate the relationship between vWf maternal plasma concentration and maternal and fetal Doppler flow measurements in pregnancies complicated by hypertension. It may provide additional insight into the pathophysiology of pregnancy-related hypertension and show the potential method for disease prevention and therapy. We created 3 study groups: pregnant women with chronic hypertension (n = 10), gestational hypertension (n = 18), preeclampsia (n = 21), and control (22 healthy pregnant women). Every woman underwent ultrasound Doppler flow measurements performed simultaneously with venous blood collection. The vWf plasma concentrations were assessed using the commercially available enzyme-linked immunosorbent assay kit. The preeclampsia group had significantly higher vWf plasma concentrations in those patients with ultrasonographic features of placental insufficiency than in those without these characteristics (638 ± 208 vs. 377 ± 74 ng/mL; p < 0.017). Our results may confirm the arrangement and severity of endothelial damage in preeclamptic patients and may have identified those patients with a significantly higher risk of developing cardiovascular disease. © 2018 S. Karger AG, Basel.

Plasma Cytokine Concentrations Indicate In-vivo Hormonal Regulation of Immunity is Altered During Long-Duration Spaceflight

NASA Technical Reports Server (NTRS)

Crician, Brian E.; Zwart, Sara R.; Mehta, Satish; Uchakin, Peter; Quiriarte, Heather A.; Pierson, Duane; Sams, Clarence F.; Smith, Scott M.

2013-01-01

Background: Aspects of immune system dysregulation associated with long-duration spaceflight have yet to be fully characterized, and may represent a clinical risk to crewmembers during deep space missions. Plasma cytokine concentration may serve as an indicator of in vivo physiological changes or immune system mobilization. Methods: The plasma concentrations of 22 cytokines were monitored in 28 astronauts during long-duration spaceflight onboard the International Space Station. Blood samples were collected three times before flight, 3-5 times during flight (depending on mission duration), at landing and 30 days post-landing. Analysis was performed by bead array immunoassay. Results: With few exceptions, minimal detectable mean plasma levels (<10 pg/ml) were observed at baseline (launch minus 180) for innate inflammatory cytokines or adaptive regulatory cytokines, however IL-1ra and several chemokines were constitutively present. An increase in the plasma concentration IL-8, IL-1ra, Tpo, CCL4, CXCL5, TNF(alpha), GM-CSF and VEGF was observed associated with spaceflight. Significant post-flight increases were observed for IL-6 and CCL2. No significant alterations were observed during or following spaceflight for adaptive/T-regulatory cytokines (IL-2, IFN(gamma), IL-17, IL4, IL-5, IL-10). Conclusions: This pattern of cytokine dysregulation suggests multiple physiological adaptations persist during flight, including inflammation, leukocyte recruitment, angiogenesis and thrombocyte regulation.

Selenium supplementation to chronic kidney disease patients on hemodialysis does not induce the synthesis of plasma glutathione peroxidase.

PubMed

Zachara, Bronislaw A; Gromadzinska, Jolanta; Zbrog, Zbigniew; Swiech, Rafal; Wasowicz, Wojciech; Twardowska, Ewa; Jablonska, Ewa; Sobala, Wojciech

2009-01-01

Numerous authors have shown that selenium (Se) concentration and glutathione peroxidase (GSH-Px) activity in plasma of chronic kidney disease (CKD) patients are lower than in healthy subjects, but there are only few publications on the level of GSH-Px protein in those patients and no reports on the effect of Se supplementation to HD patients on the level of this enzyme. Se concentration and GSH-Px protein level in plasma were measured in a group of 30 CKD patients on hemodialysis (HD) supplemented with 200 microg Se/day for 3 months, and 28 patients on HD administered with placebo. Se concentration was measured by graphite furnace atomic absorption spectrometry and plasma GSH-Px protein level by the sandwich ELISA method using polyclonal antibody specific for human plasma GSH-Px. Se concentration in patients on placebo did not change throughout the 3-month study period, but increased significantly in Se supplemented group. Se supplementation to CKD patients on HD had no effect on the level of GSH-Px protein. The lack of GSH-Px protein in CKD patients on HD is not linked to Se deficiency since the level of this element increased after Se supplementation while enzyme protein level did not change. The damaged kidney of HD patients is unable to synthesize GSH-Px, even after induction with selenium.

[Determination and pharmacokinetics of main components for Psoralea corylifolia-Myristica fragrants drug pair by using UPLC-MS/MS].

PubMed

Gao, Jia-Rong; Xu, Shuang-Zhi; Han, Yan-Quan; Wei, Liang-Bing; Jiang, Hui; Song, Jun-Mei; Xue, Xue

2017-05-01

To conduct multiple-reaction monitoring(MRM) quantitative analysis with ultra-high performance liquid chromatography coupled with mass spectrometry method(UPLC-MS/MS), determine the concentrations of psoralen, isopsoralen, bakuchiol and dehydrodiisoeugenol in plasma under positive iron mode with chloramghenicol as internal standard, and investigate the pharmacokinetics process of the main components before and after oral administration of drug pair Psoralea corylifolia -Myristica fragrants. Thirty-six SD rats were randomly divided into three group(A, B, C) and received P. corylifolia extract, P. corylifolia-M. fragrants extract, and M. fragrants extract respectively by intragastric administration. The plasma samples were collected at different time points. In the plasma samples, psoralen, isopsoralen, bakuchiol and dehydrodiisoeugenol showed good linear relationship within concentration rages of 0.098 125 to 39.25, 0.084 37 to 33.75, 0.046 875 to 18.75, and 0.11 to 2.2 mg•L⁻¹ respectively. The precision and stability results showed that the determination method of plasma concentration for such compositions was stable and reliable. The pharmacokinetic parameters obtained by DAS 2.0 showed varying differences before and after compatibility. According to the experimental results, the compatibility of P. corylifolia and M. fragrants can significantly impact the pharmacokinetic process of main components, expand their distribution and accelerate their metabolism and elimination in vivo. Copyright© by the Chinese Pharmaceutical Association.

Application of a novel liquid chromatography/tandem mass spectrometry method for the determination of antazoline in human plasma: Result of ELEPHANT-I [ELEctrophysiological, pharmacokinetic and hemodynamic effects of PHenazolinum (ANTazoline mesylate)] human pharmacokinetic study.

PubMed

Giebułtowicz, Joanna; Piotrowski, Roman; Baran, Jakub; Kułakowski, Piotr; Wroczyński, Piotr

2016-05-10

Antazoline is a first-generation antihistaminic agent with antiarrhythmic quinidine-like properties. In some countries, it is widely used for termination of cardiac arrhythmias, especially atrial fibrillation (AF). However, no human pharmacokinetic studies have been conducted with intravenous antazoline. The aim of our study was to develop and validate a novel liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the determination of antazoline in human plasma: the ELEPHANT-I [ELEctrophysiological, pharmacokinetic and hemodynamic effects of PHenazolinum (ANTazoline mesylate)] human pharmacokinetic study. Antazoline was extracted from plasma using liquid-liquid extraction. The concentration of the analyte was measured by LC-MS/MS with xylometazoline as an internal standard. The method was validated for linearity, precision, accuracy, stability (freeze/thaw stability, stability in autosampler, short and long term stability), dilution integrity and matrix effect. The analyzed validation criteria were fulfilled. The method was applied to a pharmacokinetic study involving 10 healthy volunteers. Following a single intravenous dose of antazoline mesylate (100 mg), the plasma concentration profile showed a relative fast elimination with a terminal elimination half-life of 2.29 h. A relatively high volume of distribution was observed (Vss=315 L). The values of mean residence time (MRT∞), area under the curve (AUC∞) and clearance were 3.45 h, 0.91 mg h L(-1) and 80.5 L h(-1), respectively. One volunteer showed significant differences in pharmacokinetic parameters. In conclusion, the proposed new LC-MS/MS method was successfully used for the first time for the determination of antazoline in human plasma. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of Active Drug Concentrations in the Pulmonary Epithelial Lining Fluid and Interstitial Fluid of Calves Injected with Enrofloxacin, Florfenicol, Ceftiofur, or Tulathromycin

PubMed Central

Foster, Derek M.; Martin, Luke G.; Papich, Mark G.

2016-01-01

Bacterial pneumonia is the most common reason for parenteral antimicrobial administration to beef cattle in the United States. Yet there is little information describing the antimicrobial concentrations at the site of action. The objective of this study was to compare the active drug concentrations in the pulmonary epithelial lining fluid and interstitial fluid of four antimicrobials commonly used in cattle. After injection, plasma, interstitial fluid, and pulmonary epithelial lining fluid concentrations and protein binding were measured to determine the plasma pharmacokinetics of each drug. A cross-over design with six calves per drug was used. Following sample collection and drug analysis, pharmacokinetic calculations were performed. For enrofloxacin and metabolite ciprofloxacin, the interstitial fluid concentration was 52% and 78% of the plasma concentration, while pulmonary fluid concentrations was 24% and 40% of the plasma concentration, respectively. The pulmonary concentrations (enrofloxacin + ciprofloxacin combined) exceeded the MIC90 of 0.06 μg/mL at 48 hours after administration. For florfenicol, the interstitial fluid concentration was almost 98% of the plasma concentration, and the pulmonary concentrations were over 200% of the plasma concentrations, exceeding the breakpoint (≤ 2 μg/mL), and the MIC90 for Mannheimia haemolytica (1.0 μg/mL) for the duration of the study. For ceftiofur, penetration to the interstitial fluid was only 5% of the plasma concentration. Pulmonary epithelial lining fluid concentration represented 40% of the plasma concentration. Airway concentrations exceeded the MIC breakpoint for susceptible respiratory pathogens (≤ 2 μg/mL) for a short time at 48 hours after administration. The plasma and interstitial fluid concentrations of tulathromcyin were lower than the concentrations in pulmonary fluid throughout the study. The bronchial concentrations were higher than the plasma or interstitial concentrations, with over 900% penetration to the airways. Despite high diffusion into the bronchi, the tulathromycin concentrations achieved were lower than the MIC of susceptible bacteria at most time points. PMID:26872361

Optimization and validation of a high-performance liquid chromatographic method with UV detection for the determination of ketoconazole in canine plasma.

PubMed

Vertzoni, M V; Reppas, C; Archontaki, H A

2006-07-24

An isocratic high-performance liquid chromatographic method with detection at 240 nm was developed, optimized and validated for the determination of ketoconazole in canine plasma. 9-Acetylanthracene was used as internal standard. A Hypersil BDS RP-C18 column (250 mm x 4.6 mm, 5 microm particle size), was equilibrated with a mobile phase composed of methanol, water and diethylamine 74:26:0.1 (v/v/v). Its flow rate was 1 ml/min. The elution time for ketoconazole and 9-acetylanthracene was approximately 9 and 8 min, respectively. Calibration curves of ketoconazole in plasma were linear in the concentration range of 0.015-10 microg/ml. Limits of detection and quantification in plasma were 5 and 15 ng/ml, respectively. Recovery was greater than 95%. Intra- and inter-day relative standard deviation for ketoconazole in plasma was less than 3.1 and 4.7%, respectively. This method was applied to the determination of ketoconazole plasma levels after administration of a commercially available tablet to dogs.

Two main metabolites of gentiopicroside detected in rat plasma by LC-TOF-MS following 2,4-dinitrophenylhydrazine derivatization.

PubMed

Wang, Zhigang; Tang, Shuhan; Jin, Yan; Zhang, Yan; Hattori, Masao; Zhang, Hailong; Zhang, Ning

2015-03-25

The metabolism of gentiopicroside in vivo was studied by LC/MS following 2,4-dinitrophenylhydrazine derivatization for the first time. The ionization efficiency of the major metabolites erythrocentaurin and gentiopicral were greatly enhanced by the new analytical method developed, and they were successfully detected in rat plasma after oral administration of gentiopicroside. Methyl 4-formylbenzoate was used as the internal standard to quantify erythrocentaurin and gentiopicral in rat plasma in negative mode by UPLC-TOF-MS. It was found that erythrocentaurin reached the maximum plasma concentration of 625.2±246.3 ng/mL at about 2 h and gentiopicral reached the maximum plasma concentration of 157.6±86.6 ng/mL at about 4 h after oral administration of gentiopicroside at a dose of 200 mg/kg. The metabolic pathway of gentiopicroside to erythrocentaurin and gentiopicral was proposed. The monoterpene compound gentiopicroside was found to be metabolized to dihydroisocoumarin in vivo which may be responsible for the pharmacological effect of gentiopicroside. The results may shed light on clinical efficacy of gentiopicroside and the new analytical method developed may assist in studies for the metabolism of other natural iridoids and secoiridoids in vivo. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of phenytoin, carbamazepine, and 10,11-carbamazepine epoxide in human plasma by high-performance liquid chromatography with ultraviolet detection.

PubMed

Bhatti, M M; Hanson, G D; Schultz, L

1998-03-01

The Bioanalytical Chemistry Department at the Madison facility of Covance Laboratories, has developed and validated a simple and sensitive method for the simultaneous determination of phenytoin (PHT), carbamazepine (CBZ) and 10,11-carbamazepine epoxide (CBZ-E) in human plasma by high-performance liquid chromatography with 10,11 dihydrocarbamazepine as the internal standard. Acetonitrile was added to plasma samples containing PHT, CBZ and CBZ-E to precipitate the plasma proteins. After centrifugation, the acetonitrile supernatant was transferred to a clean tube and evaporated under N2. The dried sample extract was reconstituted in 0.4 ml of mobile phase and injected for analysis by high-performance liquid chromatography. Separation was achieved on a Spherisorb ODS2 analytical column with a mobile phase of 18:18:70 acetonitrile:methanol:potassium phosphate buffer. Detection was at 210 nm using an ultraviolet detector. The mean retention times of CBZ-E, PHT and CBZ were 5.8, 9.9 and 11.8 min, respectively. Peak height ratios were fit to a least squares linear regression algorithm with a 1/(concentration)2 weighting. The method produces acceptable linearity, precision and accuracy to a minimum concentration of 0.050 micrograms ml-1 in human plasma. It is also simple and convenient, with no observable matrix interferences.

Electronic Cigarette Nicotine Delivery Can Exceed that of Combustible Cigarettes: A Preliminary Report

PubMed Central

Ramôa, Carolina P.; Hiler, Marzena M.; Spindle, Tory R; Lopez, Alexa A.; Karaoghlanian, Nareg; Lipato, Thokozeni; Breland, Alison B.; Shihadeh, Alan; Eissenberg, Thomas

2016-01-01

Introduction Electronic cigarettes (ECIGs) aerosolize a liquid that usually contains propylene glycol and/or vegetable glycerin, flavorants, and the dependence-producing drug nicotine in various concentrations. This laboratory study examined the relationship between liquid nicotine concentration on plasma nicotine concentration and puffing behavior in experienced ECIG users. Methods Sixteen ECIG-experienced participants used a 3.3-Volt ECIG battery attached to a 1.5-Ohm dual-coil “cartomizer” loaded with 1 ml of a flavored propylene glycol/vegetable glycerin liquid to complete four sessions, at least 2 days apart, that differed by nicotine concentration (0, 8, 18, or 36 mg/ml). In each session, participants completed two 10-puff ECIG use bouts (30-sec puff interval) separated by 60 minutes. Venous blood was sampled to determine plasma nicotine concentration. Puff duration, volume, and average flow rate were measured. Results Immediately after bout 1, mean plasma nicotine concentration was 5.5 ng/ml (SD=7.7) for 0 mg/ml liquid, with significantly (p<0.05) higher mean concentrations observed for the 8 (mean=17.8 ng/ml, SD=14.6), 18 (mean=25.9 ng/ml, SD=17.5), and 36 mg/ml (mean=30.2 ng/ml; SD=20.0) concentrations; a similar pattern was observed for bout 2. For bout 1, at 36 mg/ml, the mean post- minus pre-bout difference was 24.1 ng/ml (SD=18.3). Puff topography data were consistent with previous results and revealed few reliable differences across conditions. Discussion This study demonstrates a relationship between ECIG liquid nicotine concentration and user plasma nicotine concentration in experienced ECIG users. Nicotine delivery from some ECIGs may exceed that of a combustible cigarette. The rationale for this higher level of nicotine delivery is uncertain. PMID:26324250

Central and peripheral blood pressures in relation to plasma advanced glycation end products in a Chinese population.

PubMed

Huang, Q-F; Sheng, C-S; Kang, Y-Y; Zhang, L; Wang, S; Li, F-K; Cheng, Y-B; Guo, Q-H; Li, Y; Wang, J-G

2016-07-01

We investigated the association of plasma AGE (advanced glycation end product) concentration with central and peripheral blood pressures and central-to-brachial blood pressure amplification in a Chinese population. The study subjects were from a newly established residential area in the suburb of Shanghai. Using the SphygmoCor system, we recorded radial arterial waveforms and derived aortic waveforms by a generalized transfer function and central systolic and pulse pressure by calibration for brachial blood pressure measured with an oscillometric device. The central-to-brachial pressure amplification was expressed as the central-to-brachial systolic blood pressure difference and pulse pressure difference and ratio. Plasma AGE concentration was measured by the enzyme-linked immunosorbent assay method and logarithmically transformed for statistical analysis. The 1051 participants (age, 55.1±13.1 years) included 663 women. After adjustment for sex, age and other confounding factors, plasma AGE concentration was associated with central but not peripheral blood pressures and with some of the pressure amplification indexes. Indeed, each 10-fold increase in plasma AGE concentration was associated with 2.94 mm Hg (P=0.04) higher central systolic blood pressure and 2.39% lower central-to-brachial pulse pressure ratio (P=0.03). In further subgroup analyses, the association was more prominent in the presence of hypercholesterolemia (+8.11 mm Hg, P=0.008) for central systolic blood pressure and in the presence of overweight and obesity (-4.89%, P=0.009), diabetes and prediabetes (-6.26%, P=0.10) or current smoking (-6.68%, P=0.045) for central-to-brachial pulse pressure ratio. In conclusion, plasma AGE concentration is independently associated with central systolic blood pressure and pulse pressure amplification, especially in the presence of several modifiable cardiovascular risk factors.

Simultaneous quantification of endogenous and exogenous plasma glucose by isotope dilution LC-MS/MS with indirect MRM of the derivative tag.

PubMed

Yu, Lingling; Wen, Chao; Li, Xing; Fang, Shiqi; Yang, Lichuan; Wang, Tony; Hu, Kaifeng

2018-03-01

Quantification of endogenous and exogenous plasma glucose can help more comprehensively evaluate the glucose metabolic status. A ratio-based approach using isotope dilution liquid chromatography tandem mass spectrometry (ID LC-MS/MS) with indirect multiple reaction monitoring (MRM) of the derivative tag was developed to simultaneously quantify endo-/exogenous plasma glucose. Using diluted D-[ 13 C 6 ] glucose as tracer of exogenous glucose, 12 C 6 / 13 C 6 glucoses were first derivatized and then data were acquired in MRM mode. The metabolism of exogenous glucose can be tracked and the concentration ratio of endo/exo-genous glucose can be measured by calculating the endo-/exo-genous glucose concentrations from peak area ratio of specific daughter ions. Joint application of selective derivatization and MRM analysis not only improves the sensitivity but also minimizes the interference from the background of plasma, which warrants the accuracy and reproducibility. Good agreement between the theoretical and calculated concentration ratios was obtained with a linear correlation coefficient (R) of 0.9969 in the range of D-glucose from 0.5 to 20.0 mM, which covers the healthy and diabetic physiological scenarios. Satisfactory reproducibility was obtained by evaluation of the intra- and inter-day precisions with relative standard deviations (RSDs) less than 5.16%, and relative recoveries of 85.96 to 95.92% were obtained at low, medium, and high concentration, respectively. The method was successfully applied to simultaneous determination of the endo-/exogenous glucose concentration in plasma of non-diabetic and type II diabetic cynomolgus monkeys. Graphical Abstract The scheme of the proposed ratio-based approach using isotope dilution LC-MS/MS with indirect MRM of the derivative tag for simultaneous quantification of endogenous and exogenous plasma glucose.

Effects of varying doses of β-nerve growth factor on the timing of ovulation, plasma progesterone concentration and corpus luteum size in female alpacas (Vicugna pacos).

PubMed

Stuart, C C; Vaughan, J L; Kershaw-Young, C M; Wilkinson, J; Bathgate, R; de Graaf, S P

2015-11-01

Ovulation in camelids is induced by the seminal plasma protein ovulation-inducing factor (OIF), recently identified as β-nerve growth factor (β-NGF). The present study measured the total protein concentration in alpaca seminal plasma using a bicinchoninic acid (BCA) protein quantification assay and found it to be 22.2±2.0mgmL(-1). To measure the effects of varying doses of β-NGF on the incidence and timing of ovulation, corpus luteum (CL) size and plasma progesterone concentration, 24 female alpacas were synchronised and treated with either: (1) 1mL 0.9% saline (n=5); (2) 4µg buserelin (n=5); (3) 1mg β-NGF protein (n=5); (4) 0.1mg β-NGF (n=5); or (5) 0.01mg β-NGF (n=4). Females were examined by transrectal ultrasonography at 1-2-h intervals between 20 and 45h after treatment or until ovulation occurred, as well as on Day 8 to observe the size of the CL, at which time blood was collected to measure plasma progesterone concentrations. Ovulation was detected in 0/5, 5/5, 5/5, 3/5 and 0/4 female alpacas treated with saline, buserelin, 1, 0.1 and 0.01mg β-NGF, respectively. Mean ovulation interval (P=0.76), CL diameter (P=0.96) and plasma progesterone concentration (P=0.96) did not differ between treatments. Mean ovulation interval overall was 26.2±1.0h. In conclusion, buserelin and 1mg β-NGF are equally effective at inducing ovulation in female alpacas, but at doses ≤0.1mg, β-NGF is not a reliable method for the induction of ovulation.

Pharmacokinetic modeling of penciclovir and BRL42359 in the plasma and tears of healthy cats to optimize dosage recommendations for oral administration of famciclovir.

PubMed

Sebbag, Lionel; Thomasy, Sara M; Woodward, Andrew P; Knych, Heather K; Maggs, David J

2016-08-01

OBJECTIVES To determine, following oral administration of famciclovir, pharmacokinetic (PK) parameters for 2 of its metabolites (penciclovir and BRL42359) in plasma and tears of healthy cats so that famciclovir dosage recommendations for the treatment of herpetic disease can be optimized. ANIMALS 7 male domestic shorthair cats. PROCEDURES In a crossover study, each of 3 doses of famciclovir (30, 40, or 90 mg/kg) was administered every 8 or 12 hours for 3 days. Six cats were randomly assigned to each dosage regimen. Plasma and tear samples were obtained at predetermined times after famciclovir administration. Pharmacokinetic parameters were determined for BRL42359 and penciclovir by compartmental and noncompartmental methods. Pharmacokinetic-pharmacodynamic (PK-PD) indices were determined for penciclovir and compared among all dosage regimens. RESULTS Compared with penciclovir concentrations, BRL42359 concentrations were 5- to 11-fold greater in plasma and 4- to 7-fold greater in tears. Pharmacokinetic parameters and PK-PD indices for the 90 mg/kg regimens were superior to those for the 30 and 40 mg/kg regimens, regardless of dosing frequency. Penciclovir concentrations in tears ranged from 18% to 25% of those in plasma. Administration of 30 or 40 mg/kg every 8 hours achieved penciclovir concentrations likely to be therapeutic in plasma but not in tears. Penciclovir concentrations likely to be therapeutic in tears were achieved only with the two 90 mg/kg regimens. CONCLUSIONS AND CLINICAL RELEVANCE In cats, famciclovir absorption is variable and its metabolism saturable. Conversion of BRL42359 to penciclovir is rate limiting. The recommended dosage of famciclovir is 90 mg/kg every 12 hours for cats infected with feline herpesvirus.

Laser system for measuring small changes in plasma tracer concentrations.

PubMed

Klaesner, J W; Pou, N A; Parker, R E; Galloway, R L; Roselli, R J

1996-01-01

The authors developed a laser-diode system that can be used for on-line optical concentration measurements in physiologic systems. Previous optical systems applied to whole blood have been hampered by artifacts introduced by red blood cells (RBCs). The system introduced here uses a commercially available filter cartridge to separate RBCs from plasma before plasma concentration measurements are made at a single wavelength. The filtering characteristics of the Cellco filter cartridge (#4007-10, German-town, MD) were adequate for use in the on-line measurement system. The response time of the filter cartridge was less than 40 seconds, and the sieving characteristics of the filter for macromolecules were excellent, with filtrate-to-plasma albumin ratios of 0.98 +/- 0.11 for studies in sheep and 0.94 +/- 0.15 for studies in dogs. The 635-nm laser diode system developed was shown to be more sensitive than the spectrophotometer used in previous studies (Klaesner et al., Annals of Biomedical Engineering, 1994; 22, 660-73). The new system was used to measure the product of filtration coefficient (Kfc) and reflection coefficient for albumin (delta f) in an isolated canine lung preparation. The delta fKfc values [mL/(cmH2O.min.100 g dry lung weight)] measured with the laser diode system (0.33 +/- 0.22) compared favorably with the delta fKfc obtained using a spectrophotometer (0.27 +/- 0.20) and with the Kfc obtained using the blood-corrected gravimetric method (0.32 +/- 0.23). Thus, this new optical system was shown to accurately measure plasma concentration changes in whole blood for physiologic levels of Kfc. The same system can be used with different optical tracers and different source wavelengths to make optical plasma concentration measurements for other physiologic applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skladnik-Sadowska, E.; Malinowski, K.; Sadowski, M. J.

The paper concerns the monitoring of high-current pulse discharges and the determination of the plasma concentration within the dense magnetized plasma by means of optical spectroscopy methods. In experiments with the large PF-1000 facility operated at IPPLM in Warsaw, Poland, attention was paid to the determination of the operational mode and electron concentration under different experimental conditions. To measure the visible radiation (VR) the use was made of the MECHELLE registered 900-spectrometer equipped with the CCD readout. The VR emission, observed at 65 deg. to the z-axis, originated from a part of the electrode surfaces, the collapsing current-sheath layer andmore » the dense plasma pinch-region (40-50 mm from the electrode ends). Considerable differences were found in the optical spectra recorded for so-called 'good shots' and for cases of some failures. Estimates of the electron concentration, which were performed with different spectroscopic techniques, showed that it ranged from 5.56x1018 cm-3 to 4.8x1019 cm-3, depending on experimental conditions. The correlation of the fusion-neutron yield and the plasma density was proved.« less

Narcolepsy Treated with Racemic Amphetamine during Pregnancy and Breastfeeding.

PubMed

Öhman, Inger; Wikner, Birgitta Norstedt; Beck, Olof; Sarman, Ihsan

2015-08-01

This case report describes a woman with narcolepsy treated with racemic amphetamine (rac-amphetamine) during pregnancy and breastfeeding with follow-up on the infant's development up to 10 months of age. The pregnancy outcome and the pharmacokinetics of rac-amphetamine were studied during breastfeeding. The pregnancy and the delivery were uneventful. Concentrations of rac-amphetamine were determined in the plasma of the mother and infant, and in the breast milk with a liquid chromatography-mass spectrometry method. Samples were obtained at 2, 5, and 9 weeks postpartum. The transfer of rac-amphetamine to the breast milk was extensive (mean milk/maternal plasma concentration ratio approximately 3). The breastfed infant had a low plasma concentration of rac-amphetamine (about 9% of the maternal plasma level) and the calculated relative infant dose was low (2%). No adverse effects were observed in the breastfed infant. The infant's somatic and psychomotor development up to 10 months of age was normal. Further studies of amphetamine prescribed for medical reasons during pregnancy and lactation are needed. © The Author(s) 2015.

Population pharmacokinetic modelling of the changes in atazanavir plasma clearance caused by ritonavir plasma concentrations in HIV‐1 infected patients

PubMed Central

Moltó, José; Estévez, Javier A.; Miranda, Cristina; Cedeño, Samandhy; Clotet, Bonaventura

2016-01-01

Aims The aim of the present study was to develop a simultaneous population pharmacokinetic model for atazanavir (ATV) incorporating the effect of ritonavir (RTV) on clearance to predict ATV concentrations under different dosing regimens in HIV‐1‐infected patients. Methods A Cross‐sectional study was carried out in 83 HIV‐1‐infected adults taking ATV 400 mg or ATV 300 mg/RTV 100 mg once daily. Demographic and clinical characteristics were registered and blood samples collected to measure drug concentrations. A population pharmacokinetic model was constructed using nonlinear mixed‐effects modelling and used to simulate six dosing scenarios. Results The selected one‐compartmental model described the pharmacokinetics of RTV and ATV simultaneously, showing exponential, direct inhibition of ATV clearance according to the RTV plasma concentration, which explained 17.5% of the variability. A mean RTV plasma concentration of 0.63 mg l–1 predicted an 18% decrease in ATV clearance. The percentages of patients with an end‐of‐dose‐interval concentration of ATV below or above the minimum and maximum target concentrations of 0.15 mg l–1 and 0.85 mg l–1 favoured the selection of the simulated ATV/RTV once‐daily regimens (ATV 400 mg, ATV 300 mg/RTV 100 mg, ATV 300 mg/RTV 50 mg, ATV 200/RTV 100 mg) over the unboosted twice‐daily regimens (ATV 300 mg, ATV 200 mg). Conclusions A one‐compartment simultaneous model can describe the pharmacokinetics of RTV and ATV, including the effect of RTV plasma concentrations on ATV clearance. This model is promising for predicting individuals' ATV concentrations in clinical scenarios, and supports further clinical trials of once‐daily doses of ATV 300 mg/RTV 50 mg or ATV 200 mg/RTV 100 mg to confirm efficacy and safety. PMID:27447851

Determination of moxifloxacin in human plasma, plasma ultrafiltrate, and cerebrospinal fluid by a rapid and simple liquid chromatography- tandem mass spectrometry method.

PubMed

Pranger, Arianna D; Alffenaar, Jan-Willem C; Wessels, A Mireille A; Greijdanus, Ben; Uges, Donald R A

2010-04-01

Moxifloxacin (MFX) is a useful agent in the treatment of multi-drug-resistant tuberculosis (MDR-TB). At Tuberculosis Centre Beatrixoord, a referral center for tuberculosis in the Netherlands, approximately 36% of the patients have received MFX as treatment. Based on the variability of MFX AUC, the variability of in vitro susceptibility to MFX of M. tuberculosis, and the variability of penetration into sanctuary sites, measuring the concentration of MFX in plasma and cerebrospinal fluid (CSF) could be recommended. Therefore, a rapid and validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyzing method with a simple pretreatment procedure was developed for therapeutic drug monitoring of MFX in human plasma and CSF. Because of the potential influence of protein binding on efficacy, we decided to determine both bound and unbound (ultrafiltrate) fraction of MFX. The calibration curves were linear in the therapeutic range of 0.05 to 5.0 mg/L plasma and CSF with CV in the range of -5.4% to 9.3%. MFX ultrafiltrate samples could be determined with the same method setup for analysis of MFX in CSF. The LC-MS-MS method developed in this study is suitable for monitoring MFX in human plasma, plasma ultrafiltrate, and CSF.

Quantification of rifampicin in human plasma and cerebrospinal fluid by a highly sensitive and rapid liquid chromatographic-tandem mass spectrometric method.

PubMed

Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A

2012-11-01

A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The assay was linear in the concentration range 25-6400 ng/mL with intra- and inter-day precision of <7% and <8%, respectively. The validated method was applied to the study of RIF pharmacokinetics in human CSF and plasma over 25 h period after a 10 mg/kg oral dose. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous determination of the HIV nucleoside analogue reverse transcriptase inhibitors lamivudine, didanosine, stavudine, zidovudine and abacavir in human plasma by reversed phase high performance liquid chromatography.

PubMed

Verweij-van Wissen, C P W G M; Aarnoutse, R E; Burger, D M

2005-02-25

A reversed phase high performance liquid chromatography method was developed for the simultaneous quantitative determination of the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine, didanosine, stavudine, zidovudine and abacavir in plasma. The method involved solid-phase extraction with Oasis MAX cartridges from plasma, followed by high performance liquid chromatography with a SymmetryShield RP 18 column and ultraviolet detection set at a wavelength of 260 nm. The assay was validated over the concentration range of 0.015-5 mg/l for all five NRTIs. The average accuracies for the assay were 92-102%, inter- and intra-day coefficients of variation (CV) were <2.5% and extraction recoveries were higher than 97%. This method proved to be simple, accurate and precise, and is currently in use in our laboratory for the quantitative analysis of NRTIs in plasma.

Determination of vigabatrin in human plasma and urine by high-performance liquid chromatography with fluorescence detection.

PubMed

Erturk, S; Aktas, E S; Atmaca, S

2001-09-05

A sensitive and specific HPLC method has been developed for the assay of vigabatrin in human plasma and urine. The assay involves derivatization with 4-chloro-7-nitrobenzofurazan, solid-phase extraction on a silica column and isocratic reversed-phase chromatography with fluorescence detection. Aspartam was used as an internal standard. The assay was linear over the concentration range of 0.2-20.0 microg/ml for plasma and 1.0-15.0 microg/ml for urine with a lower limit of detection of 0.1 microg/ml using 0.1 ml of starting volume of the sample. Both the within-day and day-to-day reproducibilities and accuracies were less than 5.46% and 1.6%, respectively. After a single oral dose of 500 mg of vigabatrin, the plasma concentration and the cumulative urinary excretion of the drug were determined.

Concentrations of amino acids in the plasma of neonatal foals with septicemia.

PubMed

Zicker, S C; Spensley, M S; Rogers, Q R; Willits, N H

1991-07-01

Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.

Pharmacokinetics of bambuterol in subjects homozygous for the atypical gene for plasma cholinesterase

PubMed Central

Bang, Ulla; Nyberg, Lars; Rosenborg, Johan; Viby-Mogensen, Jørgen

1998-01-01

Aims It has been assumed that both plasma cholinesterase (EC 3.1.1.8) and oxidative enzymes are needed for optimum formation of the bronchodilator terbutaline from its biscarbamate prodrug bambuterol. The present study aimed at investigating the fate of bambuterol in subjects with deficient plasma cholinesterase but with normal oxidative (CYP2D6) capability. Methods The pharmacokinetics of bambuterol and terbutaline were studied in four healthy subjects (two men and two women) being homozygous for the atypical gene for plasma cholinesterase. Their oxidative metabolism was apparently good as they were all rapid metabolizers of debrisoquine. Bambuterol hydrochloride 20 mg was given orally once daily for 10 days, and plasma and urine samples were taken for 1.5 days (plasma) and 4.5 days (urine) after administration of the last dose. Results The pharmacokinetic parameters in the present study were grossly similar to those found in a study of bambuterol in subjects with normal plasma cholinesterase activity (N). However, subjects with atypical cholinesterase had a shorter terminal half-life of bambuterol (a measure of uptake rate), 4.8–12.6 h vs 8.3–22.3 h in N, and slightly higher plasma concentrations of bambuterol (average concentrations 1.9–3.7 nmol l−1vs 1.5–3.1 nmol l−1 in N). Peak/trough terbutaline plasma concentrations ratios (2.1–3.2) were somewhat increased, but average plasma concentrations (8.3–14.5 nmol l−1) and terminal half-life (16.5–21.8 h) of terbutaline did not differ. Conclusions In Caucasian populations, one subject out of 2500 is homozygous for the atypical gene for plasma cholinesterase. The atypical enzyme has a much lower affinity for bambuterol than the normal enzyme. Nevertheless, the subjects with atypical cholinesterase were able to produce terbutaline as efficiently as normal subjects. This might be explained by an altered uptake and metabolism in the absence of plasma cholinesterase, or the importance of this enzyme for the formation of terbutaline from bambuterol in vivo may have been overestimated. PMID:9643621

Elevated Plasma Norepinephrine After In Utero Exposure to Cocaine and Marijuana

PubMed Central

Mirochnick, Mark; Meyer, Jerrold; Frank, Deborah A.; Cabral, Howard; Tronick, Edward Z.; Zuckerman, Barry

2008-01-01

Objective To compare plasma catecholamine concentrations between cocaine-exposed and unexposed term newborns and to determine the relationship between plasma catecholamines and newborn behavior. Methods Forty-six newborn infants participating in a prospective study of the neonatal and long-term effects of prenatal cocaine exposure were studied. Based on maternal self-report, maternal urine screening, and infant meconium analysis, 24 infants were classified as cocaine-exposed and 22 as unexposed. Between 24 and 72 hours postpartum, plasma samples for norepinephrine (NE), epinephrine, dopamine, and dihydroxyphenylalanine analysis were obtained. The Neonatal Behavioral Assessment Scale was administered at 1 to 3 days of age and at 2 weeks of age by examiners masked to the drug exposure status of the newborns. Results The cocaine-exposed newborns had increased plasma NE concentrations when compared to the unexposed infants (geometric mean, 923 pg/mL vs 667 pg/mL). There were no significant differences in plasma epinephrine, dopamine, or dihydroxyphenylalanine concentrations. Analysis for the effect of potential confounding variables revealed that maternal marijuana use was also associated with increased plasma NE, although birth weight, gender, and maternal use of alcohol or cigarettes were not. Geometric mean plasma NE was 1164 pg/mL in those infants with in utero exposure to both cocaine and marijuana compared to 812 pg/mL in those exposed to only cocaine and 667 pg/mL in those exposed to neither. Among the cocaine-exposed infants, plasma NE concentration correlated with an increased score for the depressed cluster (r = .53) and a decreased score for the orientation cluster (r = −.43) of the Neonatal Behavioral Assessment Scale administered at 1 to 3 days of age. Adjusting for marijuana exposure had no effect on these relationships between plasma NE and the depressed and orientation clusters. Conclusion Plasma NE is increased in newborns exposed to cocaine and marijuana. Increased plasma NE is associated with selected neurobehavioral disturbances among cocaine exposed infants at 1 to 3 days of life but not at 2 weeks. PMID:9093298

Pulmonary administration of aerosolised fentanyl: pharmacokinetic analysis of systemic delivery

PubMed Central

Mather, Laurence E; Woodhouse, Annie; Ward, M Elizabeth; Farr, Stephen J; Rubsamen, Reid A; Eltherington, Lorne G

1998-01-01

Aims Pulmonary drug delivery is a promising noninvasive method of systemic administration. Our aim was to determine whether a novel breath-actuated, microprocessor-controlled metered dose oral inhaler (SmartMist™, Aradigm Corporation) could deliver fentanyl in a way suitable for control of severe pain. Methods Aersolised pulmonary fentanyl base 100–300 μg was administered to healthy volunteers using SmartMist™ and the resultant plasma concentration-time data were compared with those from the same doses administered by intravenous (i.v.) injection in the same subjects. Results Plasma concentrations from SmartMist™ were similar to those from i.v. injection. Time-averaged bioavailability based upon nominal doses averaged 100%, and was >50% within 5 min of delivery. Fentanyl systemic pharmacokinetics were similar to those previously reported with no trends to dose-dependence from either route. Side-effects (e.g. sedation, lightheadedness) were the same from both routes. Conclusions Fentanyl delivery using SmartMist™ can provide analgetically relevant plasma drug concentrations. This, combined with its ease of noninvasive use and transportability, suggests a strong potential for field and domicilliary use, and for patient controlled analgesia without the need for i.v. cannulae. PMID:9690947

Plasma cortisol in Alzheimer’s disease with or without depressive symptoms

PubMed Central

Zvěřová, Martina; Fišar, Zdeněk; Jirák, Roman; Kitzlerová, Eva; Hroudová, Jana; Raboch, Jiří

2013-01-01

Background Cortisol is presumed to be a risk factor for stress- and age-related disorders, such as depressive disorder and Alzheimer’s disease (AD). The aim of this study was to investigate the association of plasma cortisol concentration with AD in presence or absence of comorbid depressive symptoms. Material/Methods Plasma cortisol concentration was measured in 80 AD patients (35 of them with depressive symptoms), 27 elderly depressive patients without AD, and 37 elderly controls. Results Compared to controls, a significant increase of mean plasma cortisol was found in AD patients but not in depressive patients. Plasma cortisol was positively correlated with cognitive impairment in AD patients. We confirmed a U-shaped association between plasma cortisol and major depression and a linear association between plasma cortisol and AD without depressive symptoms. Significantly increased relative risk of disease in people with high plasma cortisol was found for AD with depressive symptoms and for AD with mild dementia. Conclusions Plasma cortisol reflects the degree of cognitive impairment in AD rather than the severity of comorbid depression. We confirmed that both hypercortisolemia and hypocortisolemia are associated with depressive disorder. Significant association between high plasma cortisol and AD was found, supporting the use of high plasma cortisol as a component of a panel of biochemical markers for AD with depressive symptoms as well as AD in the early stage of dementia development. PMID:23955525

Sensitivity of the activated partial thromboplastin time, the dilute Russell's viper venom time, and the kaolin clotting time for the detection of the lupus anticoagulant: a direct comparison using plasma dilutions.

PubMed

Martin, B A; Branch, D W; Rodgers, G M

1996-01-01

Increasing dilutions of lupus anticoagulant (LA) plasmas from twelve patients were used to directly compare the sensitivity of four tests for LA. The tests evaluated were the modified Bell and Alton activated partial thromboplastin time (APTT), an APTT using a commercially prepared partial thromboplastin (Platelin LS APTT), a modified dilute Russell's viper venom time (DRVVT), and a modified kaolin clotting time (KCT). LAs were detected in all twelve plasmas by each of three tests and eleven of twelve plasmas in a fourth test when undiluted patient plasma was used. Repeating the tests after diluting the LA plasmas with normal platelet-free plasma (PFP) showed that the KCT was the most sensitive test for LA, detecting eleven of twelve LAs at a dilution of 10% patient plasma and ten of twelve LAs at a dilution of 5% patient plasma. The modified Bell and Alton APTT and the modified DRVVT had similar sensitivities at a patient plasma concentration of 10%, detecting seven of twelve and eight of twelve LAs, respectively. The Platelin LS APTT detected only four of twelve LAs at a patient plasma concentration of 10%. Our results indicate that the modified KCT is a sensitive method for the detection of LAs. The modified Bell and Alton APTT and the DRVVT were less sensitive.

Effect of carvedilol on plasma adiponectin concentration in patients with chronic heart failure.

PubMed

Yamaji, Masayuki; Tsutamoto, Takayoshi; Tanaka, Toshinari; Kawahara, Chiho; Nishiyama, Keizo; Yamamoto, Takashi; Fujii, Masanori; Horie, Minoru

2009-06-01

Patients with a high plasma adiponectin have a poor prognosis in chronic heart failure (CHF). Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are reported to increase the plasma adiponectin concentration, but the effect of beta-blockers on plasma adiponectin in patients with CHF remains unknown. Blood samples were collected at before and 6 months after administration of carvedilol in 44 CHF patients. The hemodynamic parameters, echocardiography, plasma concentrations of brain natriuretic peptide (BNP), norepinephrine and adiponectin were measured. Six months after treatment, there were significantly decreased plasma concentrations of adiponectin (15.8 +/-1.4 to 11.0 +/-1.1 microg/ml, P<0.0001), BNP and norepinephrine and increased left ventricular ejection fraction (LVEF). On stepwise multivariable analyses, a higher plasma adiponectin concentration before treatment (rs=-0.561, P<0.0001) was a significant independent predictor of a greater decrease in adiponectin concentration and the decrease in plasma adiponectin concentration was significantly correlated with the improvement of LVEF (r=-0.561, P<0.0001). These findings indicate that carvedilol decreases plasma adiponectin concentration and that the decrease in plasma adiponectin is associated with the improvement of LVEF after treatment with carvedilol in CHF patients.

Plasma folate levels and associated factors in women planning to become pregnant in a population with high prevalence of neural tube defects.

PubMed

Ma, Rui; Wang, Linlin; Jin, Lei; Li, Zhiwen; Ren, Aiguo

2017-07-17

Optimal blood folate levels of women before pregnancy are critical to the prevention of neural tube defects (NTDs). However, few studies have focused on blood folate levels of women planning to become pregnant. The aims of this study were to assess plasma folate levels in women who planned to become pregnant in a population with high prevalence of NTDs, to identify factors associated with plasma folate levels, and to evaluate the risk of NTDs at the population level. A total of 2065 women were enrolled at the time of premarital health check-up in two rural counties in northern China from November 2009 to December 2012. Fasting venous blood samples were collected and plasma folate concentrations were measured by microbiological method. The overall median of plasma folate was 10.5 nmol/L. 50% of the women had a plasma folate level below 10.5 nmol/L, a cutoff for megaloblastic anemia, and 88% below 18 nmol/L, a proposed optimal plasma folate level for the prevention of NTDs. Folic acid supplementation was the only factor to be associated with plasma folate concentrations, but only 1.9% of the women reported having taken folic acid supplements. A population risk of 29.3 NTD cases per 10,000 births was predicted. Women who planned to become pregnant had very low plasma folate in the population. Folic acid supplementation was the only factor to be associated with a high plasma folate concentration. High NTD risk would remain if women would get pregnant without having taken folic acid supplements. Birth Defects Research 109:1039-1047, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

UPLC-MS/MS assay of riluzole in human plasma and cerebrospinal fluid (CSF): Application in samples from spinal cord injured patients.

PubMed

Sarkar, Mahua; Grossman, Robert G; Toups, Elizabeth G; Chow, Diana S-L

2017-11-30

In the present study, a sensitive and robust LC-MS/MS method has been developed and validated for the quantification of riluzole in human plasma and cerebrospinal fluid (CSF) in clinical samples from patients with spinal cord injury (SCI). Riluzole and its labeled internal standard (IS) were isolated from plasma and CSF by liquid-liquid extraction using ethyl acetate. Riluzole (m/z 235→166) and IS (m/z 238→169) were detected by electrospray ionization (ESI) using multiple reaction monitoring (MRM) in a positive mode. The assay was linear in the concentration range of 0.5 (LLOQ, signal/noise ratio>10)-800ng/ml in plasma, and 1.0 (LLOQ)-800ng/ml in CSF samples. The intra- and inter-day accuracy in plasma were 94.2-110.0% and 97.8-102.0%, respectively, and those in CSF were 87.6-105.1% and 91.9-98.8%, respectively. The intra- and inter-day precision were 2.2-7.2% and 4.0-9.1%, respectively, in plasma, and 1.4-14.1% and 2.6-11.5%, respectively in CSF. Matrix effect was negligible from both matrices with signal percentages of 97.6-100.6% in plasma and 99.4-106.4% in CSF. The recoveries were >75% in plasma, >84% in CSF with low protein (53.9mg/dl), and >68% in CSF with high protein (348.2mg/dl). This method was successfully applied to quantify riluzole concentrations in plasma and CSF from patients with SCI. Copyright © 2017 Elsevier B.V. All rights reserved.

LC-QTOF-MS-based targeted metabolomics of arginine-creatine metabolic pathway-related compounds in plasma: application to identify potential biomarkers in pediatric chronic kidney disease.

PubMed

Benito, Sandra; Sánchez, Alicia; Unceta, Nora; Andrade, Fernando; Aldámiz-Echevarria, Luis; Goicolea, M Aránzazu; Barrio, Ramón J

2016-01-01

Chronic kidney disease (CKD) is a major epidemiologic problem which causes several disturbances in adults and in pediatrics. Despite being a worldwide public health problem, information available for CKD in the pediatric population is scarce. For that reason, an ion-pair reversed-phase liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method has been developed and validated in order to analyze 16 amino acids, amino acid derivatives, and analogous compounds related to the arginine-creatine metabolic pathway that are suspicious of being increased or decreased in plasma from patients with CKD. The analytical method involved the addition of dithiothreitol, a reducing agent which reduces disulfide and thus giving total aminothiol concentration, as well as a simple precipitation of plasma proteins. Moreover, despite amino acids being usually derivatized to improve their retention time and to enhance their signal, for this method, an ion-pairing reagent was used, thus avoiding the need for derivatization. Subsequently, analysis of plasma from pediatric patients suffering from CKD and control pediatrics was carried out. As a result, glycine, citrulline, creatinine, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) were significantly increased in patients with CKD, regardless of their creatinine level, whereas in addition to these compounds dimethylglycine was also increased when CKD patients had plasma creatinine concentrations above 12 μg mL(-1), thus all are suggested as potential biomarkers for renal impairment.

Sensitive method for the quantitative determination of proguanil and its metabolites in rat blood and plasma by liquid chromatography-mass spectrometry.

PubMed

Leveque, Nathalie L; Charman, William N; Chiu, Francis C K

2006-01-18

A sensitive, simple and fast liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 1-(4-chlorophenyl)biguanide (4CPB), was developed and validated over a concentration range of 1-2000 ng/mL using only 50 microL of blood or plasma. After a simple solvent precipitation procedure, the supernatant was analysed directly by HPLC-MS/MS. Separation was achieved using an ethyl-linked phenyl reverse phase column with polar endcapping with an acetonitrile-water-formic acid gradient. Mass spectrometry was performed using a triple quadrupole mass spectrometer operating in positive electrospray ionization mode. The elution of PG (254.07-->169.99), CG (252.12-->195.02) and 4CPB (212.06-->153.06) was monitored using selected reaction monitoring. The three compounds and the internal standard (chloroproguanil) were well separated by HPLC and no interfering peaks were detected at the usual concentrations found in blood and plasma. The limit of quantification of PG and CG was 1 ng/mL and 5 ng/mL for 4CPB in rat blood and plasma. The extraction efficiency of PG, CG and 4CPB from rat blood and plasma was higher than 73%. The intra- and inter-assay variability of PG, CG and 4CPB were within 12% and the accuracy within +/-5%. This new assay offers higher sensitivity and a much shorter run time over earlier methods.

Blood proteins analysis by Raman spectroscopy method

NASA Astrophysics Data System (ADS)

Artemyev, D. N.; Bratchenko, I. A.; Khristoforova, Yu. A.; Lykina, A. A.; Myakinin, O. O.; Kuzmina, T. P.; Davydkin, I. L.; Zakharov, V. P.

2016-04-01

This work is devoted to study the possibility of plasma proteins (albumin, globulins) concentration measurement using Raman spectroscopy setup. The blood plasma and whole blood were studied in this research. The obtained Raman spectra showed significant variation of intensities of certain spectral bands 940, 1005, 1330, 1450 and 1650 cm-1 for different protein fractions. Partial least squares regression analysis was used for determination of correlation coefficients. We have shown that the proposed method represents the structure and biochemical composition of major blood proteins.

Selected problems with boron determination in water treatment processes. Part I: comparison of the reference methods for ICP-MS and ICP-OES determinations.

PubMed

Kmiecik, Ewa; Tomaszewska, Barbara; Wątor, Katarzyna; Bodzek, Michał

2016-06-01

The aim of the study was to compare the two reference methods for the determination of boron in water samples and further assess the impact of the method of preparation of samples for analysis on the results obtained. Samples were collected during different desalination processes, ultrafiltration and the double reverse osmosis system, connected in series. From each point, samples were prepared in four different ways: the first was filtered (through a membrane filter of 0.45 μm) and acidified (using 1 mL ultrapure nitric acid for each 100 mL of samples) (FA), the second was unfiltered and not acidified (UFNA), the third was filtered but not acidified (FNA), and finally, the fourth was unfiltered but acidified (UFA). All samples were analysed using two analytical methods: inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The results obtained were compared and correlated, and the differences between them were studied. The results show that there are statistically significant differences between the concentrations obtained using the ICP-MS and ICP-OES techniques regardless of the methods of sampling preparation (sample filtration and preservation). Finally, both the ICP-MS and ICP-OES methods can be used for determination of the boron concentration in water. The differences in the boron concentrations obtained using these two methods can be caused by several high-level concentrations in selected whole-water digestates and some matrix effects. Higher concentrations of iron (from 1 to 20 mg/L) than chromium (0.02-1 mg/L) in the samples analysed can influence boron determination. When iron concentrations are high, we can observe the emission spectrum as a double joined and overlapping peak.

Opioid Concentrations in Oral Fluid and Plasma in Cancer Patients With Pain.

PubMed

Heiskanen, Tarja; Langel, Kaarina; Gunnar, Teemu; Lillsunde, Pirjo; Kalso, Eija A

2015-10-01

Measuring opioid concentrations in pain treatment is warranted in situations where optimal opioid analgesia is difficult to reach. To assess the usefulness of oral fluid (OFL) as an alternative to plasma in opioid concentration monitoring in cancer patients on chronic opioid therapy. We collected OFL and plasma samples from 64 cancer patients on controlled-release (CR) oral morphine, CR oral oxycodone, or transdermal (TD) fentanyl for pain. Samples were obtained on up to five separate days. A total of 213 OFL and plasma samples were evaluable. All patients had detectable amounts of the CR or TD opioid in both plasma and OFL samples. The plasma concentrations of oxycodone and fentanyl (determination coefficient R(2) = 0.628 and 0.700, respectively), but not morphine (R(2) = 0.292), were moderately well correlated to the daily opioid doses. In contrast to morphine and fentanyl (mean OFL/plasma ratio 2.0 and 3.0, respectively), the OFL oxycodone concentrations were significantly higher than the respective plasma concentrations (mean OFL/plasma ratio 14.9). An active transporter could explain the much higher OFL vs. plasma concentrations of oxycodone compared with morphine and fentanyl. OFL analysis is well suited for detecting the studied opioids. For morphine and fentanyl, an approximation of the plasma opioid concentrations is obtainable, whereas for oxycodone, the OFL/plasma concentration relationship is too variable for reliable approximation results. Copyright © 2015 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Highly sensitive quantification for human plasma-targeted metabolomics using an amine derivatization reagent.

PubMed

Arashida, Naoko; Nishimoto, Rumi; Harada, Masashi; Shimbo, Kazutaka; Yamada, Naoyuki

2017-02-15

Amino acids and their related metabolites play important roles in various physiological processes and have consequently become biomarkers for diseases. However, accurate quantification methods have only been established for major compounds, such as amino acids and a limited number of target metabolites. We previously reported a highly sensitive high-throughput method for the simultaneous quantification of amines using 3-aminopyridyl-N-succinimidyl carbamate as a derivatization reagent combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Herein, we report the successful development of a practical and accurate LC-MS/MS method to analyze low concentrations of 40 physiological amines in 19 min. Thirty-five of these amines showed good linearity, limits of quantification, accuracy, precision, and recovery characteristics in plasma, with scheduled selected reaction monitoring acquisitions. Plasma samples from 10 healthy volunteers were evaluated using our newly developed method. The results revealed that 27 amines were detected in one of the samples, and that 24 of these compounds could be quantified. Notably, this new method successfully quantified metabolites with high accuracy across three orders of magnitude, with lowest and highest averaged concentrations of 31.7 nM (for spermine) and 18.3 μM (for α-aminobutyric acid), respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

A Modified LC/MS/MS Method with Enhanced Sensitivity for the Determination of Scopolamine in Human Plasma

NASA Technical Reports Server (NTRS)

Wang, Zuwei; Vaksman, Zalman; Putcha, Lakshmi

2008-01-01

Intranasal scopolamine is a choice drug for the treatment of motion sickness during space flight because of its quick onset of action, short half-life and favorable sideeffects profile. The dose administered usually ranges between 0.1 and 0.4 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids using existing sensitive LC/MS/MS method, especially when the biological sample volumes are limited. To measure scopolamine in human plasma to facilitate pharmacokinetic evaluation of the drug, we developed a sensitive LC/MS/MS method using 96 well micro elution plates for solid phase extraction (SPE) of scopolamine in human plasma. Human plasma (100-250 micro L) were loaded onto Waters Oasis HLB 96 well micro elution plate and eluted with 50 L of organic solvent without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 3 minutes. The mobile phase for separation was 80:20 (v/v) methanol: ammonium acetate (30 mM) in water. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 right arrow 138.1 and internal standard hyoscyamine m/z = 290.2 right arrow 124.1. The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at about 1.1 and 1.7 min respectively. The linear range is 25-10000 pg/mL for scopolamine in human plasma with correlation coefficients greater than 0.99 and CV less than 0.5%. The intra-day and inter-day CVs are less than 15% for quality control samples with concentrations of 75,300, and 750 pg/mL of scopolamine in human plasma. SPE using 96 well micro elution plates allows rapid sample preparation and enhanced sensitivity for the LC/MS/MS determination of scopolamine in a small volume of biological samples. The new method is also cost effective since it uses a small volume of organic solvents compared to the methods using SPE cartridges or regular 96 well SPE plates. This method can be successfully used for bioavailability and pharmacokinetic evaluations of scopolamine, especially when volumes of biological samples are limited. Further investigation to use automated SPE system with 96 well micro elution plates is planned.

Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study

PubMed Central

2012-01-01

Background Since betaine is an osmolyte and methyl donor, and abnormal betaine loss is common in diabetes mellitus (>20% patients), we investigated the relationship between betaine and the post-methionine load rise in homocysteine, in diabetes and control subjects. The post-methionine load test is reported to be both an independent vascular risk factor and a measure of betaine sufficiency. Methods Patients with type 2 diabetes (n = 34) and control subjects (n = 17) were recruited. We measured baseline fasting plasma and 4-hour post-methionine load (L-methionine, 0.1 mg/kg body weight) concentrations of homocysteine, betaine, and the betaine metabolite N,N-dimethylglycine. Baseline urine excretions of betaine, dimethylglycine and glucose were measured on morning urine samples as the ratio to urine creatinine. Statistical determinants of the post-methionine load increase in homocysteine were identified in multiple linear regression models. Results Plasma betaine concentrations and urinary betaine excretions were significantly (p < 0.001) more variable in the subjects with diabetes compared with the controls. Dimethylglycine excretion (p = 0.00014) and plasma dimethylglycine concentrations (p = 0.039) were also more variable. In diabetes, plasma betaine was a significant negative determinant (p < 0.001) of the post-methionine load increase in homocysteine. However, it was not conclusive that this was different from the relationship in the controls. In the patients with diabetes, a strong relationship was found between urinary betaine excretion and urinary glucose excretion (but not with plasma glucose). Conclusions Both high and low plasma betaine concentrations, and high and low urinary betaine excretions, are more prevalent in diabetes. The availability of betaine affects the response in the methionine load test. The benefits of increasing betaine intake should be investigated. PMID:22510294

Plasma capric acid concentrations in healthy subjects determined by high-performance liquid chromatography.

PubMed

Shrestha, Rojeet; Hui, Shu-Ping; Imai, Hiromitsu; Hashimoto, Satoru; Uemura, Naoto; Takeda, Seiji; Fuda, Hirotoshi; Suzuki, Akira; Yamaguchi, Satoshi; Hirano, Ken-Ichi; Chiba, Hitoshi

2015-09-01

Capric acid (FA10:0, decanoic acid) is a medium-chain fatty acid abundant in tropical oils such as coconut oil, whereas small amounts are present in milk of goat, cow, and human. Orally ingested FA10:0 is transported to the liver and quickly burnt within it. Only few reports are available for FA10:0 concentrations in human plasma. Fasting (n = 5, male/female = 3/2, age 31 ± 9.3 years old) and non-fasting (n = 106, male/female = 44/62, age 21.9 ± 3.2 years old) blood samples were collected from apparently healthy Japanese volunteers. The total FA10:0 in the plasma were measured by high-performance liquid chromatography after derivatization with 2-nitrophenylhydrazine followed by UV detection. Inter and intra-assay coefficient of variation of FA10:0 assay at three different concentrations ranged in 1.7-3.9 and 1.3-5.4%, respectively, with an analytical recovery of 95.2-104.0%. FA10:0 concentration was below detection limit (0.1 µmol/L) in each fasting human plasma. FA10:0 was not detected in 50 (47.2%) of 106 non-fasting blood samples, while 29 (27.4%) plasma samples contained FA10:0 less than or equal to 0.5 µmol/L (0.4 ± 0.1), and 27 (25.5%) contained it at more than 0.5 µmol/L (0.9 ± 0.3). A half of the non-fasting plasma samples contained detectable FA10:0. This simple, precise, and accurate high-performance liquid chromatography method might be useful for monitoring plasma FA10:0 during medium-chain triglycerides therapy. © The Author(s) 2015.

Nitric oxide plays a role in the regulation of adrenal blood flow and adrenocorticomedullary functions in the llama fetus

PubMed Central

Riquelme, Raquel A; Sánchez, Gina; Liberona, Leonel; Sanhueza, Emilia M; Giussani, Dino A; Blanco, Carlos E; Hanson, Mark A; Llanos, Aníbal J

2002-01-01

The hypothesis that nitric oxide plays a key role in the regulation of adrenal blood flow and plasma concentrations of cortisol and catecholamines under basal and hypoxaemic conditions in the llama fetus was tested. At 0.6-0.8 of gestation, 11 llama fetuses were surgically prepared for long-term recording under anaesthesia with vascular and amniotic catheters. Following recovery all fetuses underwent an experimental protocol based on 1 h of normoxaemia, 1 h of hypoxaemia and 1 h of recovery. In nine fetuses, the protocol occurred during fetal i.v. infusion with saline and in five fetuses during fetal i.v. treatment with the nitric oxide synthase inhibitor l-NAME. Adrenal blood flow was determined by the radiolabelled microsphere method during each of the experimental periods during saline infusion and treatment with l-NAME. Treatment with l-NAME during normoxaemia led to a marked fall in adrenal blood flow and a pronounced increase in plasma catecholamine concentrations, but it did not affect plasma ACTH or cortisol levels. In saline-infused fetuses, acute hypoxaemia elicited an increase in adrenal blood flow and in plasma ACTH, cortisol, adrenaline and noradrenaline concentrations. Treatment with l-NAME did not affect the increase in fetal plasma ACTH, but prevented the increments in adrenal blood flow and in plasma cortisol and adrenaline concentrations during hypoxaemia in the llama fetus. In contrast, l-NAME further enhanced the increase in fetal plasma noradrenaline. These data support the hypothesis that nitric oxide has important roles in the regulation of adrenal blood flow and adrenal corticomedullary functions during normoxaemia and hypoxaemia functions in the late gestation llama fetus. PMID:12356897

Early Changes in Clinical, Functional, and Laboratory Biomarkers in Workers at Risk of Indium Lung Disease

PubMed Central

Virji, M. Abbas; Trapnell, Bruce C.; Carey, Brenna; Healey, Terrance; Kreiss, Kathleen

2014-01-01

Rationale: Occupational exposure to indium compounds, including indium–tin oxide, can result in potentially fatal indium lung disease. However, the early effects of exposure on the lungs are not well understood. Objectives: To determine the relationship between short-term occupational exposures to indium compounds and the development of early lung abnormalities. Methods: Among indium–tin oxide production and reclamation facility workers, we measured plasma indium, respiratory symptoms, pulmonary function, chest computed tomography, and serum biomarkers of lung disease. Relationships between plasma indium concentration and health outcome variables were evaluated using restricted cubic spline and linear regression models. Measurements and Main Results: Eighty-seven (93%) of 94 indium–tin oxide facility workers (median tenure, 2 yr; median plasma indium, 1.0 μg/l) participated in the study. Spirometric abnormalities were not increased compared with the general population, and few subjects had radiographic evidence of alveolar proteinosis (n = 0), fibrosis (n = 2), or emphysema (n = 4). However, in internal comparisons, participants with plasma indium concentrations ≥ 1.0 μg/l had more dyspnea, lower mean FEV1 and FVC, and higher median serum Krebs von den Lungen-6 and surfactant protein-D levels. Spline regression demonstrated nonlinear exposure response, with significant differences occurring at plasma indium concentrations as low as 1.0 μg/l compared with the reference. Associations between health outcomes and the natural log of plasma indium concentration were evident in linear regression models. Associations were not explained by age, smoking status, facility tenure, or prior occupational exposures. Conclusions: In indium–tin oxide facility workers with short-term, low-level exposure, plasma indium concentrations lower than previously reported were associated with lung symptoms, decreased spirometric parameters, and increased serum biomarkers of lung disease. PMID:25295756

Experimentally induced mastitis and metritis modulate soy bean derived isoflavone biotransformation in diary cows.

PubMed

Kowalczyk-Zieba, I; Woclawek-Potocka, I; Piskula, M K; Piotrowska-Tomala, K K; Boruszewska, D; Bah, M M; Siemieniuch, M J; Skarzynski, D J

2011-12-01

The present study compared the changes in isoflavone (daidzein and genistein) and their metabolite (equol and para-ethyl-phenol) concentrations in the blood plasma of cows with induced mastitis and metritis after feeding with soy bean. Sixteen cows were divided into four groups: control for mastitis group, cows with induced mastitis group, control for metritis group, and cows with induced metritis group. All cows were fed a single dose of 2.5 kg of soy bean and then blood samples were taken from the jugular vein for 8 h at predetermined intervals. The concentrations of soy bean-derived isoflavones and their active metabolites were measured in the blood plasma on HPLC system. β-Glucuronidase activity in the blood plasma of cows was measured by fluorometric method. In the blood plasma of cows with induced mastitis and metritis, we found considerably higher concentrations and time-dependent increase in isoflavone metabolites (equol and para-ethyl-phenol) with reference to cyclic cows (P < 0.05). Moreover, we noticed significant decrease of genistein in the blood plasma of the cows with induced metritis compared with control cows (P < 0.05). In addition, in the blood plasma of the cows with induced metritis, we found an increase in β-glucuronidase activity compared with control cows (P < 0.05). In conclusion, health status of the females influenced the concentrations of isoflavone metabolites in the blood plasma of the cows. Experimentally induced mastitis and metritis increased isoflavone absorption, biotransformation and metabolism. Therefore, we suggest that cows with induced mastitis and metritis are more exposed to active isoflavone metabolite actions than healthy cows. Copyright © 2011. Published by Elsevier Inc.

Plasma and cerebrospinal fluid pharmacokinetics of erlotinib and its active metabolite OSI-420.

PubMed

Broniscer, Alberto; Panetta, John C; O'Shaughnessy, Melinda; Fraga, Charles; Bai, Feng; Krasin, Matthew J; Gajjar, Amar; Stewart, Clinton F

2007-03-01

To report cerebrospinal fluid (CSF) penetration of erlotinib and its metabolite OSI-420. Pharmacokinetic measurements were done in plasma (days 1, 2, 3, and 8 of therapy) and, concurrently, in plasma and CSF (before and at 1, 2, 4, 8, and 24 h after dose on day 34 of therapy) in an 8-year-old patient diagnosed with glioblastoma who received local irradiation and oral erlotinib in a phase I protocol. CSF samples were collected from a ventriculoperitoneal shunt, which was externalized because of infection. Erlotinib concentrations were determined by liquid chromatography/mass spectrometry. CSF penetration of erlotinib and OSI-420 were estimated by a compartmental model and by calculating the ratio of CSF to plasma 24-h area under concentration-time curve (AUC(0-24)). This patient was assigned to receive erlotinib at a dose level of 70 mg/m(2), but the actual daily dose was 75 mg (78 mg/m(2)). Erlotinib and OSI-420 plasma pharmacokinetic variables on days 8 and 34 overlapped to suggest that steady state had been reached. Whereas erlotinib and OSI-420 AUC(0-24) in plasma on day 34 were 30,365 and 2,527 ng h/mL, respectively, the correspondent AUC(0-24) in the CSF were 2,129 and 240 ng h/mL, respectively. Erlotinib and OSI-420 CSF penetration were 7% and approximately 9%, respectively, using both estimate methods. The maximum steady-state CSF concentration of erlotinib was approximately 130 ng/mL (325 nmol/L). The plasma pharmacokinetics of erlotinib in this child overlapped with results described in adults. Oral administration of erlotinib achieves CSF concentrations comparable with those active against several cancer cell lines in preclinical models.

Temporal changes in concentrations of amino acids in plasma and whole blood of healthy neonatal foals from birth to two days of age.

PubMed

Zicker, S C; Rogers, Q R

1994-07-01

Temporal changes, as well as differences in distribution, in concentrations of 24 amino acids in plasma and whole blood of neonatal foals were determined from birth to 2 days of age. In addition, differences in concentrations of amino acids in plasma between mare and foal pairs were determined at birth. Significant (P < 0.05) hypoaminoacidemia existed for 15 amino acids in plasma of foals at birth, compared with mares (paired t-test). Concentrations of 7 amino acids (aspartate, glutamate, glutamine, glycine, hydroxyproline, phenylalanine, proline) in plasma of foals were higher (P < 0.05) at birth than in mares, and concentrations of 2 (taurine, tryptophan) were not different (P > 0.05). Significant (P < 0.05) temporal changes for concentrations of 19 of 24 amino acids in plasma were observed during the 48-hour period. Concentrations of 13 of the 19 amino acids in plasma that had significant changes were higher (P < 0.05) at 48 hours. Significant (P > 0.05) effect of time on concentration of 5 amino acids (alanine, methionine, phenylalanine, taurine, threonine) in plasma was not found after birth. Temporal changes in concentrations of 7 amino acids (alanine, asparagine, glutamine, histidine, hydroxyproline, methionine, and threonine) in whole blood were not significantly (P > 0.05) different from those in plasma. Temporal changes for concentrations of the remaining 17 amino acids in whole blood were significantly (P < 0.05) different, compared with plasma. Distribution of the concentrations of 18 amino acids between whole blood and plasma was significantly (P < 0.05) different.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of parvoviral enteritis on plasma citrulline concentration in dogs.

PubMed

Dossin, O; Rupassara, S I; Weng, H-Y; Williams, D A; Garlick, P J; Schoeman, J P

2011-01-01

Plasma citrulline concentration is a reliable marker of global enterocyte mass in humans and is markedly decreased in diffuse small intestinal diseases. However, the relationship between acute intestinal damage and plasma citrulline concentration in dogs has never been documented. That dogs with parvoviral enteritis have a lower plasma citrulline concentration than healthy dogs and that plasma citrulline concentration is a predictor of death in puppies with parvoviral enteritis. Sixty-one dogs with spontaneous parvoviral enteritis and 14 healthy age-matched control dogs. Observational cohort study. Plasma citrulline concentration was measured by liquid chromatography and tandem mass spectrometry in blood samples collected at admission and each day until death or discharge from the hospital. Parvovirus enteritis was confirmed by electron microscopy on a fecal sample. Median (interquartile range) plasma citrulline concentrations at admission were 2.8 μmol/L (range: 0.3, 49.0; P < .001 versus controls) in survivors (n = 49), 2.1 μmol/L (range: 0.5, 6.4, P < .001 versus controls) in nonsurvivors (n = 12) and 38.6 μmol/L (range: 11.4, 96.1) in controls (n = 14), respectively. There was no significant difference in plasma citrulline concentration between survivors and nonsurvivors within the parvovirus-infected puppies, and plasma citrulline concentration was not significantly associated with outcome in parvoviral enteritis. There were no significant changes in plasma citrulline concentration over the 8-day follow-up period. Parvovirus enteritis is associated with a severe decrease in plasma citrulline concentration that does not appear to have any significant prognostic value. Copyright © 2011 by the American College of Veterinary Internal Medicine.

Childhood obesity treatment; Effects on BMI SDS, body composition, and fasting plasma lipid concentrations

PubMed Central

Fonvig, Cilius Esmann; Dahl, Maria; Mollerup, Pernille Maria; Lausten-Thomsen, Ulrik; Pedersen, Oluf; Hansen, Torben; Holm, Jens-Christian

2018-01-01

Objective The body mass index (BMI) standard deviation score (SDS) may not adequately reflect changes in fat mass during childhood obesity treatment. This study aimed to investigate associations between BMI SDS, body composition, and fasting plasma lipid concentrations at baseline and during childhood obesity treatment. Methods 876 children and adolescents (498 girls) with overweight/obesity, median age 11.2 years (range 1.6–21.7), and median BMI SDS 2.8 (range 1.3–5.7) were enrolled in a multidisciplinary outpatient treatment program and followed for a median of 1.8 years (range 0.4–7.4). Height and weight, body composition measured by dual-energy X-ray absorptiometry, and fasting plasma lipid concentrations were assessed at baseline and at follow-up. Lipid concentrations (total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), non-HDL, and triglycerides (TG)) were available in 469 individuals (264 girls). Linear regressions were performed to investigate the associations between BMI SDS, body composition indices, and lipid concentrations. Results At baseline, BMI SDS was negatively associated with concentrations of HDL (p = 6.7*10−4) and positively with TG (p = 9.7*10−6). Reductions in BMI SDS were associated with reductions in total body fat percentage (p<2*10−16) and percent truncal body fat (p<2*10−16). Furthermore, reductions in BMI SDS were associated with improvements in concentrations of TC, LDL, HDL, non-HDL, LDL/HDL-ratio, and TG (all p <0.0001). Changes in body fat percentage seemed to mediate the changes in plasma concentrations of TC, LDL, and non-HDL, but could not alone explain the changes in HDL, LDL/HDL-ratio or TG. Among 81 individuals with available lipid concentrations, who increased their BMI SDS, 61% improved their body composition, and 80% improved their lipid concentrations. Conclusion Reductions in the degree of obesity during multidisciplinary childhood obesity treatment are accompanied by improvements in body composition and fasting plasma lipid concentrations. Even in individuals increasing their BMI SDS, body composition and lipid concentrations may improve. PMID:29444114

Low plasma selenium concentrations in critically ill children: the interaction effect between inflammation and selenium deficiency

PubMed Central

2014-01-01

Introduction Low plasma selenium concentrations are frequent in critically ill patients. However, whether this is due to systemic inflammation, a deficient nutritional state or both is still not clear. We aimed to determine the factors associated with low plasma selenium in critically ill children while considering the inflammatory response and nutritional status. Method A prospective study was conducted in 173 children (median age 34 months) with systemic inflammatory response who had plasma selenium concentrations assessed 48 hours after admission and on the 5th day of ICU stay. The normal reference range was 0.58 μmol/L to 1.6 μmol/L. The outcome variable was ‘low plasma selenium’, which was defined as plasma selenium values below the distribution median during this period. The main explanatory variables were age, malnutrition, sepsis, C-reactive protein (CRP), and clinical severity scores. The data were analyzed using a Binomial Generalized Estimating Equations model, which includes the correlation between admission and 5th day responses. Results Malnutrition and CRP were associated with low plasma selenium. The interaction effect between these two variables was significant. When CRP values were less than or equal to 40 mg/L, malnutrition was associated with low plasma selenium levels (odds ratio (OR) = 3.25, 95% confidence interval (CI) 1.39 to 7.63, P = 0.007; OR = 2.98, 95% CI 1.26 to 7.06, P = 0.013; OR = 2.49, 95% CI 1.01 to 6.17, P = 0.049, for CRP = 10, 20 and 40 mg/L, respectively). This effect decreased as CRP concentrations increased and there was loose significance when CRP values were >40 mg/L. Similarly, the effect of CRP on low plasma selenium was significant for well-nourished patients (OR = 1.13; 95% CI 1.06 to 1.22, P <0.001) but not for the malnourished (OR = 1.03; 95% CI 0.99 to 1.08, P = 0.16). Conclusions There is a significant interaction between the magnitude of the inflammatory response and malnutrition on low plasma selenium. This interaction should be considered when interpreting plasma concentrations as an index of selenium status in patients with systemic inflammation as well as in the decision on selenium supplementation. PMID:24886623

Screening Methods for Metal-Containing Nanoparticles in Water

EPA Science Inventory

Screening-level analysis of water for metal-containing nanoparticles is achieved with single particle-inductively coupled plasma mass spectrometry (SP-ICPMS). This method measures both the concentration of nanoparticles containing an analyte metal and the mass of the metal in eac...

Development and validation of an HPLC method for the rapid and simultaneous determination of 6-mercaptopurine and four of its metabolites in plasma and red blood cells.

PubMed

Hawwa, Ahmed F; Millership, Jeff S; Collier, Paul S; McElnay, James C

2009-02-20

An HPLC method has been developed and validated for the rapid determination of mercaptopurine and four of its metabolites; thioguanine, thiouric acid, thioxanthine and methylmercaptopurine in plasma and red blood cells. The method involves a simple treatment procedure based on deproteinisation by perchloric acid followed by acid hydrolysis and heating for 45min at 100 degrees C. The developed method was linear over the concentration range studied with a correlation coefficient >0.994 for all compounds in both plasma and erythrocytes. The lower limits of quantification were 13, 14, 3, 2, 95pmol/8 x 10(8) RBCs and 2, 5, 2, 3, 20ng/ml plasma for thioguanine, thiouric acid, mercaptopurine, thioxanthine and methylmercaptopurine, respectively. The method described is selective and sensitive enough to analyse the different metabolites in a single run under isocratic conditions. Furthermore, it has been shown to be applicable for monitoring these metabolites in paediatric patients due to the low volume requirement (200microl of plasma or erythrocytes) and has been successfully applied for investigating population pharmacokinetics, pharmacogenetics and non-adherence to therapy in these patients.

IgY14 and SuperMix immunoaffinity separations coupled with liquid chromatography-mass spectrometry for human plasma proteomic biomarker discovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Tujin; Zhou, Jianying; Gritsenko, Marina A.

2012-02-01

Interest in the application of advanced proteomics technologies to human blood plasma- or serum-based clinical samples for the purpose of discovering disease biomarkers continues to grow; however, the enormous dynamic range of protein concentrations in these types of samples (often >10 orders of magnitude) represents a significant analytical challenge, particularly for detecting low-abundance candidate biomarkers. In response, immunoaffinity separation methods for depleting multiple high- and moderate-abundance proteins have become key tools for enriching low-abundance proteins and enhancing detection of these proteins in plasma proteomics. Herein, we describe IgY14 and tandem IgY14-Supermix separation methods for removing 14 high-abundance and up tomore » 60 moderate-abundance proteins, respectively, from human blood plasma and highlight their utility when combined with liquid chromatography-tandem mass spectrometry for interrogating the human plasma proteome.« less

Determination of irinotecan and its metabolite SN-38 in dried blood spots using high-performance liquid-chromatography with fluorescence detection.

PubMed

Hahn, Roberta Z; Arnhold, Priscila C; Andriguetti, Natália B; Schneider, Anelise; Klück, Helena M; Dos Reis, Simone L; Bastiani, Marcos Frank; Kael, Igor; da Silva, Anne Caroline Cezimbra; Schwartsmann, Gilberto; Antunes, Marina V; Linden, Rafael

2018-02-20

Irinotecan (IRI) is an antineoplastic drug widely used for the treatment of colorectal and advanced pancreatic cancer. Despite its clinical utility, the clinical use of IRI is associated with potentially severe hematopoietic and gastrointestinal toxicities. The quantification of IRI and its active metabolite SN-38 in dried blood spots (DBS) may be an alternative to individualize the drug dose through a minimally invasive and easy collection method. The aim of this study was to develop and validate a simple and fast HPLC-FL assay for simultaneous IRI and SN-38 measurement in DBS, with adequate analytical performance for clinical use. The method employs liquid extraction of one 8mm disk of whole blood, followed by separation in a reversed phase Eclipse Plus C8 column (150×4.6mm, 5μm). Detection was performed with a fluorescence detector, with excitation wavelength of 370 and emission of 420 for IRI and 540nm for SN-38 and internal standard (camptothecin). Total analytical run time was 17min. Mobile phase was a mixture of 0.1M phosphate buffer pH 4.0 and acetonitrile (80:20, v/v), at 1mLmin -1 . The assay was linear in the range 10-3,000ngmL -1 and from 0.5 to 300ngmL -1 for IRI and SN-38, respectively. Precision assays presented CV% of 2.71-5.65 and 2.15-10.07 for IRI and SN-38, respectively, and accuracy in the range of 94.26-100.93 and 94.24-99.33%. IRI and SN-38 were stable at 25 and 42°C for 14days in DBS samples. The method was applied to DBS samples obtained from fingerpicks from 19 volunteers receiving IRI in single or combined chemotherapy regimens, collected 1 and 24h after beginning of the infusion. The estimated plasma concentration of IRI and SN-38 in sample collected 1h after star of infusion had 16 of 19 values within the ±20% range of the measured plasma concentrations. On the other hand, predictions of IRI and SN-38 plasma concentrations from DBS measurements obtained 24h after the beginning of the infusion were poor. AUC of IRI that was calculated using plasma and DBS-estimated concentrations, with a high correlation (r=0.918). The method presented suitable characteristics for the clinical use. However, translation of IRI and SN-38 DBS to plasma concentrations is challenging due to the compound's variable plasma/blood partition. Copyright © 2017 Elsevier B.V. All rights reserved.

Iron, Zinc, Folate, and Vitamin B-12 Status Increased among Women and Children in Yaoundé and Douala, Cameroon, 1 Year after Introducing Fortified Wheat Flour

PubMed Central

Nankap, Martin; Ndjebayi, Alex O; Allen, Lindsay H; Shahab-Ferdows, Setareh; Gimou, Marie-Madeleine; Friedman, Avital; Tarini, Ann; Stamm, Rosemary A; Brown, Kenneth H

2017-01-01

Background: Few data are available on the effectiveness of large-scale food fortification programs. Objective: We assessed the impact of mandatory wheat flour fortification on micronutrient status in Yaoundé and Douala, Cameroon. Methods: We conducted representative surveys 2 y before and 1 y after the introduction of fortified wheat flour. In each survey, 10 households were selected within each of the same 30 clusters (n = ∼300 households). Indicators of inflammation, malaria, anemia, and micronutrient status [plasma ferritin, soluble transferrin receptor (sTfR), zinc, folate, and vitamin B-12] were assessed among women aged 15–49 y and children 12–59 mo of age. Results: Wheat flour was consumed in the past 7 d by ≥90% of participants. Postfortification, mean total iron and zinc concentrations of flour samples were 46.2 and 73.6 mg/kg (target added amounts were 60 and 95 mg/kg, respectively). Maternal anemia prevalence was significantly lower postfortification (46.7% compared with 39.1%; adjusted P = 0.01), but mean hemoglobin concentrations and child anemia prevalence did not differ. For both women and children postfortification, mean plasma concentrations were greater for ferritin and lower for sTfR after adjustments for potential confounders. Mean plasma zinc concentrations were greater postfortification and the prevalence of low plasma zinc concentration in women after fortification (21%) was lower than before fortification (39%, P < 0.001); likewise in children, the prevalence postfortification (28%) was lower than prefortification (47%, P < 0.001). Mean plasma total folate concentrations were ∼250% greater postfortification among women (47 compared with 15 nmol/L) and children (56 compared with 20 nmol/L), and the prevalence of low plasma folate values was <1% after fortification in both population subgroups. In a nonrepresentative subset of plasma samples, folic acid was detected in 77% of women (73% of those fasting) and 93% of children. Mean plasma and breast-milk vitamin B-12 concentrations were >50% greater postfortification. Conclusion: Although the pre-post survey design limits causal inference, iron, zinc, folate, and vitamin B-12 status increased among women and children in urban Cameroon after mandatory wheat flour fortification. PMID:28592513

Iron, Zinc, Folate, and Vitamin B-12 Status Increased among Women and Children in Yaoundé and Douala, Cameroon, 1 Year after Introducing Fortified Wheat Flour.

PubMed

Engle-Stone, Reina; Nankap, Martin; Ndjebayi, Alex O; Allen, Lindsay H; Shahab-Ferdows, Setareh; Hampel, Daniela; Killilea, David W; Gimou, Marie-Madeleine; Houghton, Lisa A; Friedman, Avital; Tarini, Ann; Stamm, Rosemary A; Brown, Kenneth H

2017-07-01

Background: Few data are available on the effectiveness of large-scale food fortification programs. Objective: We assessed the impact of mandatory wheat flour fortification on micronutrient status in Yaoundé and Douala, Cameroon. Methods: We conducted representative surveys 2 y before and 1 y after the introduction of fortified wheat flour. In each survey, 10 households were selected within each of the same 30 clusters ( n = ∼300 households). Indicators of inflammation, malaria, anemia, and micronutrient status [plasma ferritin, soluble transferrin receptor (sTfR), zinc, folate, and vitamin B-12] were assessed among women aged 15-49 y and children 12-59 mo of age. Results: Wheat flour was consumed in the past 7 d by ≥90% of participants. Postfortification, mean total iron and zinc concentrations of flour samples were 46.2 and 73.6 mg/kg (target added amounts were 60 and 95 mg/kg, respectively). Maternal anemia prevalence was significantly lower postfortification (46.7% compared with 39.1%; adjusted P = 0.01), but mean hemoglobin concentrations and child anemia prevalence did not differ. For both women and children postfortification, mean plasma concentrations were greater for ferritin and lower for sTfR after adjustments for potential confounders. Mean plasma zinc concentrations were greater postfortification and the prevalence of low plasma zinc concentration in women after fortification (21%) was lower than before fortification (39%, P < 0.001); likewise in children, the prevalence postfortification (28%) was lower than prefortification (47%, P < 0.001). Mean plasma total folate concentrations were ∼250% greater postfortification among women (47 compared with 15 nmol/L) and children (56 compared with 20 nmol/L), and the prevalence of low plasma folate values was <1% after fortification in both population subgroups. In a nonrepresentative subset of plasma samples, folic acid was detected in 77% of women (73% of those fasting) and 93% of children. Mean plasma and breast-milk vitamin B-12 concentrations were >50% greater postfortification. Conclusion: Although the pre-post survey design limits causal inference, iron, zinc, folate, and vitamin B-12 status increased among women and children in urban Cameroon after mandatory wheat flour fortification.

Pharmacodynamics of Promethazine in Human Subjects

NASA Technical Reports Server (NTRS)

Gatlin, K. T.; Boyd, J. L.; Wang, Z.; Das, H.; Putcha, L.

2005-01-01

Promethazine (PMZ) is the drug of choice for the treatment of symptoms associated with space motion sickness in astronauts. Side effects of PMZ include sedation, dizziness and cognitive performance impairment. In this study, we examined pharmacodynamics (PD) in human subjects and validated methods for evaluating cognitive performance effects of medications in space. METHODS: PMZ (12.5,25, and 50 mg) or placebo was administered by IM injection to human subjects in a randomized double-blind treatment design. Samples and data were collected for 72 h post dose. PD evaluation was performed using a battery of performance tests administered using WinSCAT (Windows based Space Cognitive Assessment Test) on a laptop computer, and ARES (ANAM Readiness Evaluation System) on a PDA, plasma concentrations of PMZ were measured using a LC-MS method. RESULTS: Results indicate a linear correlation between PMZ concentration and cognitive performance parameters (p<0.01). Test accuracy decreased and test completion time and response time increased significantly with increasing plasma PMZ concentration. CONCLUSIONS: These results suggest a concentration dependent decrement in cognitive performance associated with PMZ. WinSCAT and ARES are sensitive tools for the assessment PMZ PD and may be applicable for such evaluations with other neurocognitive drugs.

Simultaneous determination of pentoxifylline, metabolites M1 (lisofylline), M4 and M5, and caffeine in plasma and dried blood spots for pharmacokinetic studies in preterm infants and neonates.

PubMed

Page-Sharp, Madhu; Strunk, Tobias; Salman, Sam; Hibbert, Julie; Patole, Sanjay K; Manning, Laurens; Batty, Kevin T

2017-11-30

Advances in bioanalytical methods are facilitating micro-volume and dried blood spot (DBS) analysis of drugs in biological matrices for pharmacokinetic studies in children and neonates. We sought to develop a UPLC-MS/MS assay for simultaneous measurement of caffeine, pentoxifylline (PTX) and three metabolites of PTX in both plasma and DBS. Caffeine, PTX, the metabolites M1 (lisofylline), M4 and M5, and the internal standards (caffeine-d 9 and PTX-d 6 ) were separated using a Waters Aquity T3 UPLC C 18 column and gradient mobile phase (water-methanol-formic acid). Retention times for caffeine, M5, M4, PTX and M1 were 1.6, 1.7, 1.9, 2.0 and 2.1min, respectively, with a run time of 5min. The precision (≤10%) and accuracy (≤15%) across the concentration range 0.1-50mg/L for caffeine, PTX and the three metabolites in plasma and DBS were within accepted limits, as were the limits of quantification (100μg/L for caffeine and 10μg/L for PTX, M1, M4 and M5). Caffeine, PTX and the metabolites were stable in DBS for >34days at room and refrigerated temperatures. Plasma and DBS samples were obtained from 24 preterm infants recruited into a clinical pharmacokinetic study of PTX. Paired analysis indicated that DBS concentrations were 9% lower than concurrent plasma concentrations for caffeine, 7% lower for PTX (consistent with the blood:plasma ratio) and 13% lower for M1 (lisofylline). The validated UPLC-MS/MS method is suitable for micro-volume plasma and DBS analysis of caffeine, PTX and its metabolites for pharmacokinetic studies in paediatric patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

NASA Astrophysics Data System (ADS)

Ghezzi, F.; Caniello, R.; Giubertoni, D.; Bersani, M.; Hakola, A.; Mayer, M.; Rohde, V.; Anderle, M.; ASDEX Upgrade Team

2014-10-01

We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples.

The hyperthermic and neurotoxic effects of 'Ecstasy' (MDMA) and 3,4 methylenedioxyamphetamine (MDA) in the Dark Agouti (DA) rat, a model of the CYP2D6 poor metabolizer phenotype.

PubMed Central

Colado, M. I.; Williams, J. L.; Green, A. R.

1995-01-01

1. The effect of administration of 3,4-methylenedioxymethamphetamine (MDMA or 'Ecstasy') and its N-demethylated product, 3,4-methylenedioxyamphetamine (MDA) on both rectal temperature and long term neurotoxic loss of cerebral 5-hydroxytryptamine (5-HT) has been studied in male and female Dark Agouti (DA) rats. The female metabolizes debrisoquine more slowly than the male and its use has been suggested as a model of the human debrisoquine 4-hydroxylase poor metabolizer phenotype. 2. A novel h.p.l.c. method was developed and used to measure plasma MDMA and MDA concentrations in the DA rats. 3. The hyperthermic response following MDMA was enhanced in female rats. Plasma MDMA concentrations were also 57% higher than in males 45 min post-injection, while plasma concentrations of MDA were 48% lower. 4. Plasma concentrations of MDMA and MDA in male rats were unaffected by pretreatment with proadifen (15 mg kg-1) or quinidine (60 mg kg-1), but the hyperthermic response to MDMA (10 mg kg-1, i.p.) was enhanced by quinidine pretreatment. 5. The hyperthermic response following MDA was greater in male DA rats, despite plasma drug concentrations being 40% higher in females 60 min after injection. 6. Seven days after a single dose of MDMA (10 mg kg-1, i.p.) there was a substantial loss in the concentration of 5-HT and 5-hydroxyindoleacetic acid (5-HIA) in cortex and hippocampus. [3H]-paroxetine binding was also decreased by 27% in the cortex, indicating that the amine loss reflected a neurodegenerative change. MDMA (5 mg kg-1, i.p.) was without effect on brain 5-HT content.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7582557

Determination of oleanolic acid in human plasma and its association with olive oil intake in healthy Spanish adults within the EPIC Spain cohort study.

PubMed

Buckland, Genevieve; Pastor, Antoni; Lujan-Barroso, Leila; Gonzalez, Carlos Alberto; Travier, Noemie; Amiano, Pilar; Huerta, José María; Agudo, Antonio; Navarro, Carmen; Chirlaque, María Dolores; Sánchez, Maria-José; Rodríguez-Barranco, Miguel; Barricarte, Aurelio; Ardanaz, Eva; Dorronsoro, Miren; Molinuevo, Amaia; Quirós, José Ramón; de la Torre, Rafael

2017-08-01

Oleanolic acid (OA) is an important triterpenic compound found in olive oil, however little is known about its concentrations in human plasma. We aimed to determine plasma OA levels in a healthy Spanish population and compare them with estimates of dietary olive oil intake. The final study sample included 141 individuals randomly selected from the European Prospective Investigation into Cancer and Nutrition Spanish cohort. Dietary olive oil intake was estimated using validated dietary history questionnaires. OA concentrations were determined in plasma (from the participants' stored blood samples) using a HPLC-MS method. Correlation coefficients between OA and olive oil intake were calculated, adjusting for center; sex; age; consumption of olives, apples, grapes, and red wine; and fasting state. The mean OA concentration in olive oil nonconsumers was 0.72 ng/mL (SD 0.82), while in the high olive oil intake group it was 1.32 ng/mL (SD 1.14). The fully adjusted partial Spearman correlations coefficients reached 0.36 (p-value < 0.001) overall, varying minimally by sex and fasting state. This is the first study providing steady-state concentrations of triterpenes in humans. The results show that there was low-to-moderate correlation between OA concentrations and olive oil intake in this population. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of an immunoassay to measure plasminogen-activator inhibitor-1 concentrations in human saliva

PubMed Central

Zhang, Xi; Dimeski, Goce; Punyadeera, Chamindie

2014-01-01

Introduction: We have previously shown that the concentrations of D-dimer are significantly elevated in saliva compared with plasma. Saliva offers several advantages compared with blood analysis. We hypothesised that human saliva contains plasminogen activator inhibitor-1 (PAI-1) and that the concentrations are not affected by the time of saliva collection. The aim was to adopt and validate an immunoassay to quantify PAI-1 concentrations in saliva and to determine whether saliva collection time has an influence in the measurement. Materials and methods: Two saliva samples (morning and afternoon) from the same day were collected from healthy subjects (N = 40) who have had no underlying heart conditions. A customized AlphaLISA® immunoassay (PerkinElmer®, MA, USA) was adopted and used to quantify PAI-1 concentrations. We validated the analytical performance of the customized immunoassay by calculating recovery of known amount of analyte spiked in saliva. Results: The recovery (95.03%), intra- (8.59%) and inter-assay (7.52%) variations were within the acceptable ranges. The median salivary PAI-1 concentrations were 394 pg/mL (interquartile ranges (IQR) 243.4–833.1 pg/mL) in the morning and 376 (129.1–615.4) pg/mL in the afternoon and the plasma concentration was 59,000 (24,000–110,000) pg/mL. Salivary PAI-1 did not correlate with plasma (P = 0.812). Conclusions: The adopted immunoassay produced acceptable assay sensitivity and specificity. The data demonstrated that saliva contains PAI-1 and that its concentration is not affected by the time of saliva collection. There is no correlation between salivary and plasma PAI-1 concentrations. Further studies are required to demonstrate the utility of salivary PAI-1 in CVD risk factor studies. PMID:24969919

Phase 1 Safety, Pharmacokinetics, and Pharmacodynamics of Dapivirine and Maraviroc Vaginal Rings: a Double-Blind Randomized Trial

PubMed Central

Chen, Beatrice A.; Panther, Lori; Marzinke, Mark A.; Hendrix, Craig W.; Hoesley, Craig J.; van der Straten, Ariane; Husnik, Marla J.; Soto-Torres, Lydia; Nel, Annalene; Johnson, Sherri; Richardson-Harman, Nicola; Rabe, Lorna K.; Dezzutti, Charlene S.

2015-01-01

Background Variable adherence limits effectiveness of daily oral and intravaginal tenofovir-containing pre-exposure prophylaxis. Monthly vaginal antiretroviral rings are one approach to improve adherence and drug delivery. Methods MTN-013/IPM 026, a multi-site, double-blind, randomized, placebo-controlled trial in 48 HIV-negative U.S. women, evaluated vaginal rings containing dapivirine (25 mg) and maraviroc (100 mg), dapivirine-only, maraviroc-only, and placebo used continuously for 28 days. Safety was assessed by adverse events. Drug concentrations were quantified in plasma, cervicovaginal fluid (CVF), and cervical tissue. Cervical biopsy explants were challenged with HIV ex vivo to evaluate pharmacodynamics. Results There was no difference in related genitourinary adverse events between treatment arms compared to placebo. Dapivirine and maraviroc concentrations rose higher initially before falling more rapidly with the combination ring compared to relatively stable concentrations with the single drug rings. Dapivirine concentrations in CVF were 1 and 5 log10 greater than cervical tissue and plasma for both rings. Maraviroc was consistently detected only in CVF. Dapivirine and maraviroc CVF and dapivirine tissue concentrations dropped rapidly after ring removal. Cervical tissue showed a significant inverse linear relationship between HIV replication and dapivirine levels. Conclusions In this first study of a combination microbicide vaginal ring, all four rings were safe and well tolerated. Tissue dapivirine concentrations were 1,000 times greater than plasma concentrations and single drug rings had more stable pharmacokinetics. Dapivirine, but not maraviroc, demonstrated concentration-dependent inhibition of HIV-1 infection in cervical tissue. Since maraviroc concentrations were consistently detectable only in CVF and not in plasma, improved drug release of maraviroc rings is needed. PMID:26034880

Simultaneous quantification of PGI2 and TXA2 metabolites in plasma and urine in NO-deficient mice by a novel UHPLC/MS/MS method.

PubMed

Kij, Agnieszka; Mateuszuk, Lukasz; Sitek, Barbara; Przyborowski, Kamil; Zakrzewska, Agnieszka; Wandzel, Krystyna; Walczak, Maria; Chlopicki, Stefan

2016-09-10

The balance between vascular prostacyclin (PGI2) generated mainly via cyclooxygenase-2 (COX-2) and its physiological antagonist platelet-derived thromboxane A2 (TXA2) formed by cyclooxygenase-1 (COX-1) determines cardiovascular homeostasis. In the present work, a novel bioanalytical method for simultaneous quantification of stable plasma and urinary metabolites of PGI2 (6-keto-PGF1α, 2,3-dinor-6-keto-PGF1α) and TXA2 (TXB2, 2,3-dinor-TXB2) using ultra high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC/MS/MS) was developed. The method was validated using artificial plasma and urine and linearity range, intra- and inter-day precision and accuracy, recovery of analytes, relative and absolute matrix effect and stability of analytes were determined. The use of artificial biofluids improved the method sensitivity as it eliminated the contribution of endogenous metabolites present in mice plasma and urine to validation procedure. The newly developed and validated method allowed to quantify 6-keto-PGF1α and TXB2 in mice plasma as well as 2,3-dinor-6-keto-PGF1α and 2,3-dinor-TXB2 in urine samples with high sensitivity and accuracy. The calibration range was established from 0.1 to 100ng/mL for all analytes using artificial biofluids and the recoveries were greater than 89.9%. All validated parameters met the criteria of acceptance specified in FDA and EMA guidance. This method was successfully employed for profiling of the changes in PGI2 and TXA2 generation in NO-deficient mice. This work demonstrated that NO-deficiency induced by L-NAME, evidenced by a fall in nitrite in plasma and urine, was associated with platelet activation, robust increase in TXB2 and mild increase in 6-keto-PGF1α concentration in plasma. Changes in 2,3-dinor-6-keto-PGF1α and 2,3-dinor-TXB2 concentration in urine were less evident suggesting that the measurements in plasma better reflect modest changes in PGI2/TXA2 homeostasis than measurements in urine. Copyright © 2016 Elsevier B.V. All rights reserved.

The influence of nutrition on the insulin-like growth factor system and the concentrations of growth hormone, glucose, insulin, gonadotropins and progesterone in ovarian follicular fluid and plasma from adult female horses (Equus caballus)

PubMed Central

2014-01-01

Background Feed intake affects the GH-IGF system and may be a key factor in determining the ovarian follicular growth rate. In fat mares, the plasma IGF-1 concentration is high with low GH and a quick follicular growth rate, in contrast to values observed in thin mares. Nothing is known regarding the long-term effects of differential feed intake on the IGF system. The objective of this experiment was to quantify IGFs, IGFBPs, GH, glucose, insulin, gonadotropin and progesterone (P4) in blood and in preovulatory follicular fluid (FF) in relation to feeding levels in mares. Methods Three years prior to the experiment, Welsh Pony mares were assigned to a restricted diet group (R, n = 10) or a well-fed group (WF, n = 9). All mares were in good health and exhibited differences in body weight and subcutaneous fat thickness. Follicular development was scanned daily and plasma was also collected daily. Preovulatory FF was collected by ultrasound-guided follicular aspiration. Hormone levels were assayed in FF and plasma with a validated RIA. Results According to scans, the total number of follicles in group R was 53% lower than group WF. Insulin and IGF-1 concentrations were higher in WF than in R mares. GH and IGF-2 concentrations were lower in plasma from WF mares than from R mares, but the difference was not significant in FF. The IGFBP-2/IGFBP-3 ratio in FF was not affected by feeding but was dramatically increased in R mare plasma. No difference in gonadotropin concentration was found with the exception of FSH, which was higher in the plasma of R mares. On the day of puncture, P4 concentrations were not affected by feeding but were higher in preovulatory FF than in plasma. Conclusions The bioavailability of IGF-1 or IGF-2, represented by the IGFBP2/IGFBP3 ratio, is modified by feed intake in plasma but not in FF. These differences partially explain the variability in follicular growth observed between well-fed mares and mares on restricted diets. PMID:25078409

Determination of geniposide in adjuvant arthritis rat plasma by ultra-high performance liquid chromatography tandem mass spectrometry method and its application to oral bioavailability and plasma protein binding ability studies.

PubMed

Chen, Jian; Wu, Hong; Xu, Guo-Bing; Dai, Miao-Miao; Hu, Shun-Li; Sun, Liang-Liang; Wang, Wei; Wang, Rong; Li, Shu-Pin; Li, Guo-Qiang

2015-04-10

A specific, sensitive and high throughput ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometric method (UHPLC-ESI-MS/MS) was established and validated to assay geniposide (GE), a promising anti-inflammatory drug, in adjuvant arthritis rat plasma: application to pharmacokinetic and oral bioavailability studies and plasma protein binding ability. Plasma samples were processed by de-proteinised with ice-cold methanol and separated on an ACQUITY UPLC™ HSS C18 column (100 mm × 2.1mm i.d., 1.8 μm particle size) at a gradient flow rate of 0.2 mL/min using acetonitrile-0.1% formic acid in water as mobile phase, and the total run time was 9 min. Mass detection was performed in selected reaction monitoring (SRM) mode with negative electro-spray ionization includes the addition of paeoniflorin (Pae) as an internal standard (IS). The mass transition ion-pair was followed as m/z 387.4 → 122.4 for GE and m/z 479.4 → 449.0 for IS. The calibration curves were linear over the concentration range of 2-50,000 ng/mL with lower limit of quantification of 2 ng/mL. The intra-day and inter-day precisions (RSD, %) of the assay were less than 8.4%, and the accuracy was within ± 6.4% in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in adjuvant arthritis rat plasma. The UHPLC-ESI-MS/MS method was successfully applied to a pharmacokinetic study of GE after oral administration of depurated GE at 33, 66, 132 mg/kg and intravenous injection at 33, 66, 132 mg/kg in adjuvant arthritis (AA) rats. In addition, it was found that GE has rapid absorption and elimination, low absolute bioavailability, high plasma protein binding ability in AA rats after oral administration within the tested dosage range. It suggested that GE showed slow distribution into the intra- and extracellular space, and the binding rate was not proportionally dependent on plasma concentration of GE when the concentration of GE was below 5.0 μg/mL. Copyright © 2015 Elsevier B.V. All rights reserved.

Maternal Choline Status, but Not Fetal Genotype, Influences Cord Plasma Choline Metabolite Concentrations.

PubMed

Visentin, Carly E; Masih, Shannon; Plumptre, Lesley; Malysheva, Olga; Nielsen, Daiva E; Sohn, Kyoung-Jin; Ly, Anna; Lausman, Andrea Y; Berger, Howard; Croxford, Ruth; El-Sohemy, Ahmed; Caudill, Marie A; O'Connor, Deborah L; Kim, Young-In

2015-07-01

Choline deficiency during pregnancy can lead to adverse birth outcomes, including impaired neurodevelopment and birth defects. Genetic variants of choline and one-carbon metabolism may also influence birth outcomes by altering plasma choline concentrations. The effects of maternal ad libitum choline intake during pregnancy and fetal genetic variants on maternal and cord concentrations of choline and its metabolites are unknown. This prospective study sought to assess the effect of 1) maternal dietary choline intake on maternal and cord plasma concentrations of choline and its metabolites, and 2) fetal genetic polymorphisms on cord plasma concentrations. The dietary choline intake of 368 pregnant Canadian women was assessed in early (0-16 wk) and late (23-37 wk) pregnancy with the use of a food frequency questionnaire. Plasma concentrations of free choline and its metabolites were measured in maternal samples at recruitment and delivery, and in the cord blood. Ten fetal genetic variants in choline and one-carbon metabolism were assessed for their association with cord plasma concentrations of free choline and its metabolites. Mean maternal plasma free choline, dimethylglycine, and trimethylamine N-oxide (TMAO) concentrations increased during pregnancy by 49%, 17%, and 13%, respectively (P < 0.005), whereas betaine concentrations decreased by 21% (P < 0.005). Cord plasma concentrations of free choline, betaine, dimethylglycine, and TMAO were 3.2, 2.0, 1.3, and 0.88 times corresponding maternal concentrations at delivery, respectively (all P < 0.005). Maternal plasma concentrations of betaine, dimethylglycine, and TMAO (r(2) = 0.19-0.51; P < 0.0001) at delivery were moderately strong, whereas maternal concentrations of free choline were not significant (r(2) = 0.12; P = 0.06), predictors of cord plasma concentrations of these metabolites. Neither maternal dietary intake nor fetal genetic variants predicted maternal or cord plasma concentrations of choline and its metabolites. These data collectively indicate that maternal choline status, but not fetal genotype, influences cord plasma concentrations of choline metabolites. This trial was registered at clinicaltrials.gov as NCT02244684. © 2015 American Society for Nutrition.

Blood Substrate Collection and Handling Procedures under Pseudo-Field Conditions: Evaluation of Suitability for Inflammatory Biomarker Measurement

PubMed Central

Danese, Andrea; Shalev, Idan; Williams, Benjamin S.; Caspi, Avshalom

2015-01-01

Routine incorporation of blood-based biomarker measurements in population studies has been hampered by challenges in obtaining samples suitable for biomarker assessment outside of laboratory settings. Here, we assessed the suitability of venous blood left unprocessed for four, 24 or 48 hours post-collection at either room temperature or 4°C for quantification of two biomarkers, Interleukin-6 (IL-6) and C-Reactive Protein (CRP). Blood samples were collected in both K2EDTA tubes and a dedicated plasma-preservation tube, P100. Dried Blood Spot (DBS) samples from the same subjects were also collected in order to compare delayed-processing plasma performance against a popular alternative collection method. K2EDTA mean plasma concentrations of both IL-6 and CRP were not significantly different from concentrations in plasma processed immediately; this was observed for tubes stored up to 48 hours pre-processing at either temperature. Concentrations of IL-6 measured in P100 tubes showed significant time-dependent increases when stored at room temperature; otherwise, levels of IL-6 and CRP were similar to those processed immediately. Levels of CRP in DBS were correlated with plasma CRP levels, even when pre-processed blood was stored for up to 48 hours. These data indicate that plasma is suitable for IL-6 and CRP estimation under data-collection conditions that involve processing delays. PMID:26652682

Blood Substrate Collection and Handling Procedures under Pseudo-Field Conditions: Evaluation of Suitability for Inflammatory Biomarker Measurement.

PubMed

Sugden, Karen; Danese, Andrea; Shalev, Idan; Williams, Benjamin S; Caspi, Avshalom

2015-01-01

Routine incorporation of blood-based biomarker measurements in population studies has been hampered by challenges in obtaining samples suitable for biomarker assessment outside of laboratory settings. Here, we assessed the suitability of venous blood left unprocessed for 4, 24, or 48 hours post-collection at either room temperature or 4°C for quantification of two biomarkers, Interleukin-6 (IL-6) and C-reactive protein (CRP). Blood samples were collected in both K2EDTA tubes and a dedicated plasma-preservation tube, P100. Dried blood spot (DBS) samples from the same subjects were also collected in order to compare delayed-processing plasma performance against a popular alternative collection method. We found that K2EDTA mean plasma concentrations of both IL-6 and CRP were not significantly different from concentrations in plasma processed immediately; this was observed for tubes stored up to 48 hours pre-processing at either temperature. Concentrations of IL-6 measured in P100 tubes showed significant time-dependent increases when stored at room temperature; otherwise, levels of IL-6 and CRP were similar to those found in samples processed immediately. Levels of CRP in DBS were correlated with plasma CRP levels, even when pre-processed blood was stored for up to 48 hours. These data indicate that plasma is suitable for IL-6 and CRP estimation under data collection conditions that involve processing delays.

High performance liquid chromatographic assay for the quantitation of total glutathione in plasma

NASA Technical Reports Server (NTRS)

Abukhalaf, Imad K.; Silvestrov, Natalia A.; Menter, Julian M.; von Deutsch, Daniel A.; Bayorh, Mohamed A.; Socci, Robin R.; Ganafa, Agaba A.

2002-01-01

A simple and widely used homocysteine HPLC procedure was applied for the HPLC identification and quantitation of glutathione in plasma. The method, which utilizes SBDF as a derivatizing agent utilizes only 50 microl of sample volume. Linear quantitative response curve was generated for glutathione over a concentration range of 0.3125-62.50 micromol/l. Linear regression analysis of the standard curve exhibited correlation coefficient of 0.999. Limit of detection (LOD) and limit of quantitation (LOQ) values were 5.0 and 15 pmol, respectively. Glutathione recovery using this method was nearly complete (above 96%). Intra-assay and inter-assay precision studies reflected a high level of reliability and reproducibility of the method. The applicability of the method for the quantitation of glutathione was demonstrated successfully using human and rat plasma samples.

Development of an ultra-high sensitive immunoassay with plasma biomarker for differentiating Parkinson disease dementia from Parkinson disease using antibody functionalized magnetic nanoparticles.

PubMed

Yang, Shieh-Yueh; Chiu, Ming-Jang; Lin, Chin-Hsien; Horng, Herng-Er; Yang, Che-Chuan; Chieh, Jen-Jie; Chen, Hsin-Hsien; Liu, Bing-Hsien

2016-06-08

It is difficult to discriminate healthy subjects and patients with Parkinson disease (PD) or Parkinson disease dementia (PDD) by assaying plasma α-synuclein because the concentrations of circulating α-synuclein in the blood are almost the same as the low-detection limit using current immunoassays, such as enzyme-linked immunosorbent assay. In this work, an ultra-sensitive immunoassay utilizing immunomagnetic reduction (IMR) is developed. The reagent for IMR consists of magnetic nanoparticles functionalized with antibodies against α-synuclein and dispersed in pH-7.2 phosphate-buffered saline. A high-Tc superconducting-quantum-interference-device (SQUID) alternative-current magnetosusceptometer is used to measure the IMR signal of the reagent due to the association between magnetic nanoparticles and α-synuclein molecules. According to the experimental α-synuclein concentration dependent IMR signal, the low-detection limit is 0.3 fg/ml and the dynamic range is 310 pg/ml. The preliminary results show the plasma α-synuclein for PD patients distributes from 6 to 30 fg/ml. For PDD patients, the concentration of plasma α-synuclein varies from 0.1 to 100 pg/ml. Whereas the concentration of plasma α-synuclein for healthy subjects is significantly lower than that of PD patients. The ultra-sensitive IMR by utilizing antibody-functionalized magnetic nanoparticles and high-Tc SQUID magnetometer is promising as a method to assay plasma α-synuclein, which is a potential biomarker for discriminating patients with PD or PDD.

Is postural tremor size controlled by interstitial potassium concentration in muscle?

PubMed Central

Lakie, M; Hayes, N; Combes, N; Langford, N

2004-01-01

Objectives: To determine whether factors associated with postural tremor operate by altering muscle interstitial K+. Methods: An experimental approach was used to investigate the effects of procedures designed to increase or decrease interstitial K+. Postural physiological tremor was measured by conventional means. Brief periods of ischaemic muscle activity were used to increase muscle interstitial K+. Infusion of the ß2 agonist terbutaline was used to decrease plasma (and interstitial) K+. Blood samples were taken for the determination of plasma K+. Results: Ischaemia rapidly reduced tremor size, but only when the muscle was active. The ß2 agonist produced a slow and progressive rise in tremor size that was almost exactly mirrored by a slow and progressive decrease in plasma K+. Conclusions: Ischaemic reduction of postural tremor has been attributed to effects on muscle spindles or an unexplained effect on muscle. This study showed that ischaemia did not reduce tremor size unless there was accompanying muscular activity. An accumulation of K+ in the interstitium of the ischaemic active muscle may blunt the response of the muscle and reduce its fusion frequency, so that the force output becomes less pulsatile and tremor size decreases. When a ß2 agonist is infused, the rise in tremor mirrors the resultant decrease in plasma K+. Decreased plasma K+ reduces interstitial K+ concentration and may produce greater muscular force fluctuation (more tremor). Many other factors that affect postural tremor size may exert their effect by altering plasma K+ concentration, thereby changing the concentration of K+ in the interstitial fluid. PMID:15201362

CYP3A activity based on plasma 4β-hydroxycholesterol during the early postpartum period has an effect on the plasma disposition of amlodipine.

PubMed

Naito, Takafumi; Kubono, Naoko; Ishida, Takuya; Deguchi, Shuhei; Sugihara, Masahisa; Itoh, Hiroaki; Kanayama, Naohiro; Kawakami, Junichi

2015-12-01

This study aimed to evaluate plasma 4β-hydroxycholesterol as an endogenous marker of CYP3A4/5 activity in early postpartum women and its impact on the plasma disposition of amlodipine. Twenty-seven early postpartum women treated with amlodipine for pregnancy-induced hypertension were enrolled. The plasma concentration of 4β-hydroxycholesterol and its ratio to cholesterol in postpartum and in non-perinatal women were evaluated. The predose plasma concentration of amlodipine was determined at steady state. The medians of the plasma 4β-hydroxycholesterol concentration at day 0-3 and 8-21 after delivery were 146 and 161 ng/mL, respectively. No significant difference was observed in the plasma concentration of 4β-hydroxycholesterol between the postpartum periods. The plasma concentration of 4β-hydroxycholesterol and its ratio to cholesterol in postpartum women were significantly higher than those in non-perinatal women. A large individual variability was observed in the dose-normalized plasma concentration of amlodipine in early postpartum women. A weak negative correlation was observed between the dose-normalized plasma concentration of amlodipine and the plasma concentration of 4β-hydroxycholesterol. In conclusion, early postpartum women possessed higher CYP3A activity based on plasma 4β-hydroxycholesterol and had a large pharmacokinetic variability in amlodipine. CYP3A activity during the early postpartum period had an effect on the plasma disposition of amlodipine. Copyright © 2015 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

The Influence of Compatibility of Rhubarb and Radix Scutellariae on the Pharmacokinetics of Anthraquinones and Flavonoids in Rat Plasma.

PubMed

Zhang, Yaqing; Zhang, Zunjian; Song, Rui

2018-06-01

Rhubarb-Radix scutellariae is a classic herb pair, which is commonly used to clear away heat and toxin in clinic. The aim of this study was to investigate the influence of compatibility of Rhubarb and Radix scutellariae on the pharmacokinetic behaviors of anthraquinones and flavonoids in rat plasma. Eighteen rats were randomly divided into three groups, and were orally administered Rhubarb and/or Radix scutellariae extracts. A sensitive and rapid UPLC-MS/MS method was developed and validated to determine the concentrations of baicalin, baicalein, wogonside, wogonin, rhein, and emodin in rat plasma. The concentrations of phase II conjugates of flavonoid aglycones and anthraquinone aglycones were also determined after hydrolyzing the plasma with sulfatase. Compared with administration of Radix scutellariae alone, co-administration of Rhubarb significantly decreased the first maximum plasma concentration (C max1 ) of baicalin, wogonside, and the phase II conjugates of baicalein, wogonin to 46.40, 61.27, 41.49, and 20.50%, respectively. The area under the plasma concentration-time curve from time zero to infinity (AUC 0-∞ ) was significantly decreased from 82.60 ± 20.22 to 51.91 ± 7.46 μM·h for rhein and 276.83 ± 98.02 to 175.42 ± 86.82 μM·h for the phase II conjugates of wogonin after compatibility. The time to reach the first maximum plasma concentration (T max1 ) of anthraquinones was shortened and the second peak of anthraquinones disappeared after compatibility. Compatibility of Rhubarb and Radix scutellariae can significantly affect the pharmacokinetic behaviors of characteristic constituents of the two herbs. The cause of these pharmacokinetic differences was further discussed combined with the in vivo ADME (absorption, disposition, metabolism, and excretion) processes of anthraquinones and flavonoids.

Clinical and Physiological Correlates of Caffeine and Caffeine Metabolites in Primary Insomnia

PubMed Central

Youngberg, Mark R.; Karpov, Irina O.; Begley, Amy; Pollock, Bruce G.; Buysse, Daniel J.

2011-01-01

Objectives: To explore the relationship between plasma concentrations of caffeine and subjective and polysomnographic measures of sleep in both good sleeper controls (GSC) and individuals with primary insomnia (PI), following the consumption of low-moderate quantities of caffeine in the home environment. Methods: 65 PI and 29 GSC, each consuming < 4 four coffee cup equivalents of caffeine daily, were recruited. Subjects completed a diary detailing sleep habits and caffeine consumption, one night of polysomnography, and a blood sample for measurement of plasma caffeine and its metabolites at bedtime. Plasma concentrations of caffeine, its primary metabolite, paraxanthine, and other metabolites were determined for each subject and correlated with self-report and polysomnographic measures. Results: No statistically significant differences were found between GSC and PI with respect to number of caffeinated beverages consumed (p = 0.91), estimated absolute caffeine ingestion (p = 0.48), time of caffeine consumption (p = 0.22), or plasma concentrations of caffeine (p = 0.92) or paraxanthine (p = 0.88). Significant correlations were found between plasma concentrations of caffeine/paraxanthine and endorsed caffeine intake (r = 0.58, p < 0.05) and estimated absolute caffeine ingestion (r = 0.57, p < 0.05). Plasma caffeine/paraxanthine was significantly correlated with percent stage 1 sleep (r = 0.32, p < 0.05). However, plasma concentrations of caffeine/paraxanthine were not significantly correlated with other subjective or polysomnographic measures of sleep disturbance in either GSC or PI. Conclusions: These data suggest that low-moderate amounts of caffeine consumed in the home environment, and mostly during morning hours, have little effect on subjective or polysomnographic measures of sleep in GSC or PI. Citation: Youngberg MR; Karpov IO; Begley A; Pollock BG; Buysse DJ. Clinical and physiological correlates of caffeine and caffeine metabolites in primary insomnia. J Clin Sleep Med 2011;7(2):196-203. PMID:21509336

The influence of gender, weight, height and BMI on pentosidine concentrations in plasma of hemodialyzed patients.

PubMed

Slowick-Zylka, Dorota; Safranow, Krzysztof; Dziedziejko, Violetta; Dutkiewicz, Grazyna; Ciechanowski, Kazimierz; Chlubek, Dariusz

2006-01-01

Advanced glycation end-products (AGEs) such as pentosidine play an important role in complications associated with chronic renal failure (CRF) and hemodialysis (HD). This study was undertaken to determine the influence of anthropometric parameters and inflammation on plasma pentosidine concentrations. We measured total and free pentosidine in the plasma of 49 patients on chronic HD. Acid hydrolysis of plasma and protein precipitation with trichloroacetic acid was done in the case of total and free pentosidine, respectively. Pentosidine was measured by high performance liquid chromatography (HPLC). C-reactive protein (CRP) was measured by the nephelometric method. A strong negative correlation between dry weight and mean concentration of total pentosidine before and after HD was found (R = -0.47, p < 0.001). This correlation was stronger in males (R = -0.47, p = 0.017) than females (R = -0.34, p = 0.10). Even stronger correlations were noted between body mass index (BMI) and total (R = -0.55, p < 0.001), as well as free (R = -0.39, p = 0.01) pentosidine. Multivariate analysis demonstrated that BMI and time on HD were two independent factors influencing total pentosidine concentrations. CRP did not correlate with pentosidine or BMI. Lower BMI values are associated with significantly higher plasma pentosidine concentrations in patients on HD. Presumably this relationship is mediated by hypercatabolism observed in these patients. Catabolism produces weight loss and reduces BMI concurrently with the induction of oxidative and carbonyl stresses that stimulate the generation of pentosidine and other harmful AGEs in dialyzed patients.

The impact of nandrolone decanoate and growth hormone on biosynthesis of steroids in rats.

PubMed

Grönbladh, Alfhild; Johansson, Jenny; Kushnir, Mark M; Bergquist, Jonas; Hallberg, Mathias

2013-12-11

Growth hormone (GH) and anabolic androgenic steroids (AAS) are commonly used in sports communities. Several studies have suggested an association between GH and AAS. We have investigated the impact of GH in rats treated with nandrolone decanoate (ND). Male Wistar rats received ND (15 mg/kg) every third day during three weeks and were subsequently treated with recombinant human GH (1.0I U/kg) for ten consecutive days. Plasma samples were collected and peripheral organs (i.e. heart, liver, testis and thymus) were dissected and weighed. Concentration of thirteen endogenous steroids was measured in the rat plasma samples using high specificity LC-MS/MS methods. Seven steroids were detected and quantified, and concentrations of estrone, testosterone, and androstenedione were significantly different among the groups, while concentrations of pregnenolone, DHEA, 17-hydroxyprogesterone and corticosterone were not altered. Administration of rhGH alone altered the plasma steroid distribution, and the results demonstrated significantly increased concentrations of plasma estrone as well as decreased concentrations of testosterone and androstenedione in the ND-treated rats. Administration of rhGH to ND-pretreated rats did not reverse the alteration of the steroid distribution induced by ND. Administration of ND decreased the weight of the thymus, and addition of rhGH did not reverse this reduction. However, rhGH administration induced an enlargement of thymus. Taken together, the plasma steroid profile differed in the four groups, i.e. control, AAS, rhGH and the combination of AAS and rhGH treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

A sensitive and rapid ultra HPLC-MS/MS method for the simultaneous detection of clopidogrel and its derivatized active thiol metabolite in human plasma.

PubMed

Peer, Cody J; Spencer, Shawn D; VanDenBerg, Dustin A H; Pacanowski, Michael A; Horenstein, Richard B; Figg, William D

2012-01-01

A sensitive, selective, and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (uHPLC-MS/MS) was developed for the simultaneous quantification of clopidogrel (Plavix(®)) and its derivatized active metabolite (CAMD) in human plasma. Derivatization of the active metabolite in blood with 2-bromo-3'-methoxy acetophenone (MPB) immediately after collection ensured metabolite stability during sample handling and storage. Following addition of ticlopidine as an internal standard and simple protein precipitation, the analytes were separated on a Waters Acquity UPLC™ sub-2 μm-C(18) column via gradient elution before detection on a triple-quadrupole MS with multiple-reaction-monitoring via electrospray ionization. The method was validated across the clinically relevant concentration range of 0.01-50 ng/mL for parent clopidogrel and 0.1-150 ng/mL (r(2)=0.99) for CAMD, with a fast run time of 1.5 min to support pharmacokinetic studies using 75, 150, or 300 mg oral doses of clopidogrel. The analytical method measured concentrations of clopidogrel and CAMD with accuracy (%DEV) <±12% and precision (%CV) of <±6%. The method was successfully applied to measure the plasma concentrations of clopidogrel and CAMD in three subjects administered single oral doses of 75, 150, and 300 mg clopidogrel. It was further demonstrated that the derivatizing agent (MPB) does not affect clopidogrel levels, thus from one aliquot of blood drawn clinically, this method can simultaneously quantify both clopidogrel and CAMD with sensitivity in the picogram per mL range. Published by Elsevier B.V.

A Sensitive and Rapid Ultra HPLC-MS/MS Method for the Simultaneous Detection of Clopidogrel and its Derivatized Active Thiol Metabolite in Human Plasma

PubMed Central

Peer, Cody J.; Spencer, Shawn D.; VanDenBerg, Dustin A. H.; Pacanowski, Michael A.; Horenstein, Richard B.; Figg, William D.

2011-01-01

A sensitive, selective, and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (uHPLC-MS/MS) was developed for the simultaneous quantification of clopidogrel (Plavix®) and its derivatized active metabolite (CAMD) in human plasma. Derivatization of the active metabolite in blood with 2-bromo-3’-methoxy acetophenone (MPB) immediately after collection ensured metabolite stability during sample handling and storage. Following addition of ticlopidine as an internal standard and simple protein precipitation, the analytes were separated on a Waters Acquity UPLC™ sub-2µm-C18 column via gradient elution before detection on a triple-quadrupole MS with multiple-reaction-monitoring via electrospray ionization. The method was validated across the clinically-relevant concentration range of 0.01–50 ng/mL for parent clopidogrel and 0.1–150 ng/mL (r2= 0.99) for CAMD, with a fast run time of 1.5 min to support pharmacokinetic studies using 75, 150, or 300 mg oral doses of clopidogrel. The analytical method measured concentrations of clopidogrel and CAMD with accuracy (%DEV) < ±12% and precision (%CV) of < ±6%. The method was successfully applied to measure the plasma concentrations of clopidogrel and CAMD in three subjects administered single oral doses of 75, 150, and 300 mg clopidogrel. It was further demonstrated that the derivatizing agent (MPB) does not affect clopidogrel levels, thus from one aliquot of blood drawn clinically, this method can simultaneously quantify both clopidogrel and CAMD with sensitivity in the picogram per mL range. PMID:22169056

An isotope dilution capillary electrophoresis/tandem mass spectrometry (CE-MS/MS) method for the simultaneous measurement of choline, betaine, and dimethylglycine concentrations in human plasma.

PubMed

Forteschi, Mauro; Zinellu, Angelo; Assaretti, Stefano; Mangoni, Arduino A; Pintus, Gianfranco; Carru, Ciriaco; Sotgia, Salvatore

2016-10-01

Plasma concentrations of choline, betaine, and dimethylglycine provide valuable information on the flow of methyl groups in key biological processes, particularly during folate deficiency states. We developed a new method to simultaneously measure these analytes in human plasma. Following sample deproteinization using acetonitrile, an aliquot was evaporated to dryness under vacuum to be then taken up by water. Finally, analytes were separated by capillary electrophoresis and detected by electrospray ionization triple-quadrupole mass spectrometry, in multiple reaction monitoring mode, using two stable isotope-labeled internal standards. Linearity of the calibration curves of each analyte was good (R(2) > 0.99). Average limits of detection (LODs) and limits of quantification (LOQs) for choline, betaine, and dimethylglycine were, respectively, 0.43, 0.62, and 0.31 μmol/L and 1.52, 2.11, and 0.97 μmol/L. Mean recovery of three replicates of two spiked concentrations levels was close to 100 % for all of the analytes. Repeatability and intermediate precision, expressed as %RSD of measurements, were <9 %. The method, applied to measure analytes in samples from 30 patients with chronic kidney disease and 30 age- and sex-matched healthy controls, was able to detect differences between groups and the sexes.

High-performance Liquid Chromatographic Ultraviolet Detection of Nilotinib in Human Plasma from Patients with Chronic Myelogenous Leukemia, and Comparison with Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Nakahara, Ryosuke; Satho, Yuhki; Itoh, Hiroki

2016-11-01

A method for determining nilotinib concentration in human plasma is proposed using high-performance liquid chromatography and ultraviolet detection. Nilotinib and the internal standard dasatinib were separated using a mobile phase of 0.5% Na 2 PO 4 H 2 O (pH 2.5)-acetonitrile-methanol (55:25:20, v/v/v) on a Capcell Pak C18 MG II column (250 × 4.6 mm) at a flow rate of 1.0 ml/min, and ultraviolet measurement at 250 nm. The calibration curve exhibited linearity over the nilotinib concentration range of 50-2,500 ng/ml at 250 nm, with relative standard deviations (n = 5) of 7.1%, 2.5%, and 2.9% for 250, 1,500, and 2,500 ng/ml, respectively. The detection limit for nilotinib was 5 ng/ml due to three blank determinations (ρ = 3). This method was successfully applied to assaying nilotinib in human plasma samples from patients with chronic myelogenous leukemia. In addition, we compared the results with those measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at BML, Inc. (a commercial laboratory). A strong correlation was observed between the nilotinib concentrations measured by our high-performance liquid chromatographic method and those obtained by LC/MS-MS (r 2 = 0.988, P < 0.01). © 2016 Wiley Periodicals, Inc.

Analysis and stability of retinol in plasma.

PubMed

Peng, Y M; Xu, M J; Alberts, D S

1987-01-01

A simple, precise, and specific high-performance liquid chromatography (HPLC) method was developed for the simultaneous measurement of retinol (ROH), 13-cis-retinoic acid (13-cRA), and 4-oxo-13-cRA. The average recovery of ROH from serum or plasma was 95%, and the precision of the assay was less than 5%. With this HPLC method, a series of studies was carried out to evaluate the stability of ROH in various matrices. ROH was stable under our HPLC assay conditions as well as in plasma- and in serum-enriched culture media; however, ROH was not stable in aqueous matrices. Serum or heparinized plasma may be routinely used for measurement of ROH concentrations, providing EDTA, oxalate, and citrate are not used as anticoagulants. Because of ROH stability, blood samples can be kept on ice in the dark for at least 24 hours prior to separation of plasma. In addition, plasma samples containing ROH can be stored for up to 1 year at -20 degrees C without loss of stability.

Analytical validation of a new point-of-care assay for serum amyloid A in horses.

PubMed

Schwartz, D; Pusterla, N; Jacobsen, S; Christopher, M M

2018-01-17

Serum amyloid A (SAA) is a major acute phase protein in horses. A new point-of-care (POC) test for SAA (Stablelab) is available, but studies evaluating its analytical accuracy are lacking. To evaluate the analytical performance of the SAA POC test by 1) determining linearity and precision, 2) comparing results in whole blood with those in serum or plasma, and 3) comparing POC results with those obtained using a previously validated turbidimetric immunoassay (TIA). Assay validation. Analytical validation of the POC test was done in accordance with American Society of Veterinary Clinical Pathology guidelines using residual equine serum/plasma and whole blood samples from the Clinical Pathology Laboratory at the University of California-Davis. A TIA was used as the reference method. We also evaluated the effect of haematocrit (HCT). The POC test was linear for SAA concentrations of up to at least 1000 μg/mL (r = 0.991). Intra-assay CVs were 13, 18 and 15% at high (782 μg/mL), intermediate (116 μg/mL) and low (64 μg/mL) concentrations. Inter-assay (inter-batch) CVs were 45, 14 and 15% at high (1372 μg/mL), intermediate (140 μg/mL) and low (56 μg/mL) concentrations. SAA results in whole blood were significantly lower than those in serum/plasma (P = 0.0002), but were positively correlated (r = 0.908) and not affected by HCT (P = 0.261); proportional negative bias was observed in samples with SAA>500 μg/mL. The difference between methods exceeded the 95% confidence interval of the combined imprecision of both methods (15%). Analytical validation could not be performed in whole blood, the sample most likely to be used stall side. The POC test has acceptable accuracy and precision in equine serum/plasma with SAA concentrations of up to at least 1000 μg/mL. Low inter-batch precision at high concentrations may affect serial measurements, and the use of the same test batch and sample type (serum/plasma or whole blood) is recommended. Comparison of results between the POC test and the TIA is not recommended. © 2018 EVJ Ltd.

HPLC detection of plasma concentrations of diclofenac in human volunteers administered with povidone-ethylcellulose-based experimental transdermal matrix-type patches.

PubMed

Mukherjee, B; Mahapatra, S; Das, S; Roy, G; Dey, S

2006-06-01

By developing a high-performance liquid chromatography (HPLC) method, we estimated the blood concentrations of diclofenac in human volunteers administered with the transdermal patches prepared with povidone-ethylcellulose and oral diclofenac tablets. Drug-excipient interaction studies were done using the FTIR technique. The external morphology of the prepared patch before and after application to human skin was analyzed with scanning electron microscopy. FTIR studies revealed that there was no predominant interaction between the drug and polymers. In vivo studies revealed that the average concentrations of drug in plasma were 376, 1562, 2953, 2902, 2864, and 2948 ng/ml after 2, 4, 8, 24, 30, and 48 h from patches each containing 50 mg of diclofenac diethylamine, respectively, and the mean concentrations of drug in plasma after the oral administration of marketed tablet containing 50 mg diclofenac sodium were 383.7, 2569, 3693.5, 162.5, and 55.3 ng/ml at 2, 4, 8, 24, and 30 h after oral administration. Values of Cmax were 3693.5 after oral administration and 2953.8 ng/ml in the case of transdermal application. From this study, we have achieved the sustained blood level of diclofenac from the experimental patches along with an analytical method based on HPLC to determine the diclofenac blood level. Copyright 2006 Prous Science.

[Population pharmacokinetics applied to optimising cisplatin doses in cancer patients].

PubMed

Ramón-López, A; Escudero-Ortiz, V; Carbonell, V; Pérez-Ruixo, J J; Valenzuela, B

2012-01-01

To develop and internally validate a population pharmacokinetics model for cisplatin and assess its prediction capacity for personalising doses in cancer patients. Cisplatin plasma concentrations in forty-six cancer patients were used to determine the pharmacokinetic parameters of a two-compartment pharmacokinetic model implemented in NONMEN VI software. Pharmacokinetic parameter identification capacity was assessed using the parametric bootstrap method and the model was validated using the nonparametric bootstrap method and standardised visual and numerical predictive checks. The final model's prediction capacity was evaluated in terms of accuracy and precision during the first (a priori) and second (a posteriori) chemotherapy cycles. Mean population cisplatin clearance is 1.03 L/h with an interpatient variability of 78.0%. Estimated distribution volume at steady state was 48.3 L, with inter- and intrapatient variabilities of 31,3% and 11,7%, respectively. Internal validation confirmed that the population pharmacokinetics model is appropriate to describe changes over time in cisplatin plasma concentrations, as well as its variability in the study population. The accuracy and precision of a posteriori prediction of cisplatin concentrations improved by 21% and 54% compared to a priori prediction. The population pharmacokinetic model developed adequately described the changes in cisplatin plasma concentrations in cancer patients and can be used to optimise cisplatin dosing regimes accurately and precisely. Copyright © 2011 SEFH. Published by Elsevier Espana. All rights reserved.

Genetic variants in CYP2B6 and CYP2A6 explain interindividual variation in efavirenz plasma concentrations of HIV-infected children with diverse ethnic origin

PubMed Central

Soeria-Atmadja, Sandra; Österberg, Emma; Gustafsson, Lars L.; Dahl, Marja-Liisa; Eriksen, Jaran; Rubin, Johanna

2017-01-01

Background Approximately 2.6 million children live with HIV globally, and efavirenz (EFV) is one of the most widely used antiretroviral agents for HIV treatment in children and adults. There are concerns about the appropriateness of current EFV dosing and it has been discussed whether EFV dosing should be adapted according to genotype in children as suggested for adults. Aim To investigate if pediatric EFV dosing should be guided by genetic variation in drug metabolizing enzymes rather than by body weight. Method EFV plasma concentrations measured for clinical purposes from all children less than 18 years old at Karolinska University Hospital, Stockholm, Sweden, treated with EFV were collected retrospectively. They were genotyped for eleven polymorphisms in genes coding for drug-metabolizing enzymes and P-glycoprotein, of potential importance for EFV disposition. Data on country of origin, sex, age, weight, HIV RNA, viral resistance patterns, CD4 cells, adherence to treatment, subjective health status and adverse events were collected from their medical records. Results Thirty-six patients and 182 (mean 5 samples/patient) EFV plasma concentration measurements from children of African, Asian and Latin American origin were included. EFV plasma concentration varied 21-fold between measurements (n = 182) (0.85–19.3 mg/L) and 9-fold measured as mean EFV plasma concentration across the subjects (1.55–13.4 mg/L). A multivariate mixed-effects restricted maximum likelihood regression model, including multiple gene polymorphisms, identified CYP2B6*6 T/T (p < 0.0005), CYP2B6*11 G/G (p < 0.0005), CYP2A6*9 A/C (p = 0.001) genotypes, age at treatment initiation (p = 0.002) and time from treatment initiation (p < 0.0005) as independent factors significantly related to loge concentration/(dose/weight). The contribution of the model to the intra- and interindividual variation were 6 and 75%, respectively (Bryk/Raudenbush R-squared level). Conclusion Genetic polymorphisms in CYP2B6 and CYP2A6 explained a significant proportion of variability in EFV plasma concentration in HIV-infected children in a multi-ethnic outpatient clinic. Knowledge about individual variants in key drug metabolizing enzyme genes could improve clinical safety and genotype directed dosing could achieve more predictable EFV plasma concentrations in HIV-infected children. PMID:28886044

Oestradiol-17β plasma concentrations after intramuscular injection of oestradiol benzoate or oestradiol cypionate in llamas (Lama glama)

PubMed Central

2010-01-01

Background Llamas (Lama glama) are induced ovulators and the process of ovulation depends on dominant follicular size. In addition, a close relationship between behavioural estrus and ovulation is not registered in llamas. Therefore, the exogenous control of follicular development with hormones aims to predict the optimal time to mate. Oestradiol-17β (E2) and its esters are currently used in domestic species, including camelids, in synchronization treatments. But, in llamas, there is no reports regarding the appropriate dosages to be used and most protocols have been designed by extrapolation from those recommended for other ruminants. The aim of the present study was to characterize plasma E2 concentrations in intact female llamas following a single intramuscular (i.m.) injection of two oestradiol esters: oestradiol benzoate (EB) and oestradiol cypionate (ECP). Methods Twelve non pregnant and non lactating sexually mature llamas were i.m. injected on day 0 with 2.5 mg of EB (EB group, n = 6) or ECP (ECP group, n = 6). Blood samples were collected immediately before injection, at 1, 6, 12, 24 h after treatment and then daily until day 14 post injection. Changes in hormone concentrations with time were analyzed in each group by analysis of variance (ANOVA) using a repeated measures (within-SS) design. Plasma E2 concentrations and area under the concentration-time curve (AUC) values were compared between groups by ANOVA. In all cases a Least-Significant Difference test (LSD) was used to determine differences between means. Hormonal and AUC data are expressed as mean ± S.E.M. Results Peak plasma E2 concentrations were achieved earlier and were higher in EB group than in ECP group. Thereafter, E2 returned to physiological concentrations earlier in EB group (day 5) than in ECP group (day 9). Although plasma E2 profiles differed over time among groups there were no differences between them on AUC values. Conclusions The i.m. injection of a single dose of both oestradiol esters resulted in plasma E2 concentrations exceeding physiological values for a variable period. Moreover, the plasma E2 profiles observed depended on the derivative of oestradiol administered. This basic information becomes relevant at defining treatment protocols including oestrogens in llamas. PMID:20149242

Effects of Renal Impairment on Steady-State Plasma Concentrations of Rivastigmine: A Population Pharmacokinetic Analysis of Capsule and Patch Formulations in Patients with Alzheimer's Disease.

PubMed

Lefèvre, Gilbert; Callegari, Francesca; Gsteiger, Sandro; Xiong, Yuan

2016-10-01

The glomerular filtration rate (GFR), a measure of renal function, decreases by approximately 10 mL/min every 10 years after the age of 40 years, which could lead to the accumulation of drugs and/or renal toxicity. Pharmacokinetic studies of drugs excreted both renally and non-renally are desirable in patients with impaired renal function, defined by parameters including estimated GFR (eGFR) and creatinine clearance (CL CR ). We describe here a population pharmacokinetic analysis of the possible effects of renal impairment on steady-state plasma concentrations of rivastigmine and its metabolite NAP226-90 after rivastigmine patch (5 cm 2 [4.6 mg/24 h], 10 cm 2 [9.5 mg/24 h], 15 cm 2 [13.3 mg/24 h], and 20 cm 2 [17.4 mg/24 h]) and capsule (1.5, 3, 4.5, and 6 mg/12 h) treatment in patients with Alzheimer's disease. The data used to conduct the current pharmacokinetic analysis were obtained from the pivotal phase III, 24-week, multicenter, randomized, double-blind, placebo- and active-controlled, parallel-group study (IDEAL). One blood sample was collected from each patient at steady-state to measure plasma concentrations of rivastigmine and NAP226-90 using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The steady-state plasma concentrations of rivastigmine and NAP226-90 were plotted against CL CR and eGFR data, and boxplots were constructed after stratification by renal function. The two groups (mild/no renal impairment vs. moderate/severe/end-stage renal impairment) showed comparable demographic covariates for all patch sizes and capsule doses. No correlation was observed between CL CR or eGFR and plasma concentrations of rivastigmine or NAP226-90. Boxplots of concentrations of rivastigmine or NAP226-90 for each dose largely overlapped for patch and capsule. Additionally, model-based estimates of plasma concentrations adjusted for body weight yielded similar results. The results of this study show that renal function does not affect rivastigmine or NAP226-90 steady-state plasma concentrations, and no dose adjustment in patients with renal impairment is required. CLINICALTRIALS.GOV: NCT00099242.

Spectrofluorimetric method for the determination of sulpiride in pharmaceutical preparations and human plasma through derivatization with 2-cyanoacetamide.

PubMed

Shah, Jasmin; Jan, M Rasul; Khan, M Naeem; Shah, Sultan

2013-01-01

A sensitive and accurate spectrofluorimetric method has been developed for the determination of sulpiride in pharmaceutical preparations and human plasma. The developed method is based on the derivatization reaction of 2-cyanoacetamide with sulpiride in 30% ammonical solution. The fluorescent derivatized reaction product exhibited maximum fluorescence intensity at 379 nm after excitation at 330 nm. The optimum conditions for derivatization reactions were studied and the fluorescence intensity versus concentration plot was found to be linear over the concentration range 0.2-20.0 µg/mL with a correlation coefficient of 0.9985. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.82 and 2.73 ng/mL, respectively. The proposed method was validated according to ICH guidelines. The effects of common excipients and co-administered drugs were also studied. The accuracy of the method was checked using the standard addition method and percent recoveries were found to be in the range of 99.00-101.25% for pharmaceutical preparations and 97.00-97.80% for spiked human plasma. The method was successfully applied to commercial formulations and the results obtained for the proposed method were compared with a high-performance liquid chromatography reference method and statistically evaluated using the Student's t-test for accuracy and the variance ratio F-test for precision. A reaction pathway was also proposed. Copyright © 2012 John Wiley & Sons, Ltd.

The pharmacokinetics of oxypurinol in people with gout

PubMed Central

Stocker, Sophie L; McLachlan, Andrew J; Savic, Radojka M; Kirkpatrick, Carl M; Graham, Garry G; Williams, Kenneth M; Day, Richard O

2012-01-01

AIMS Our aim was to identify and quantify the sources of variability in oxypurinol pharmacokinetics and explore relationships with plasma urate concentrations. METHODS Non-linear mixed effects modelling was applied to concentration–time data from 155 gouty patients with demographic, medical history and renal transporter genotype information. RESULTS A one compartment pharmacokinetic model with first order absorption best described the oxypurinol concentration–time data. Renal function and concomitant medicines (diuretics and probenecid), but not transporter genotype, significantly influenced oxypurinol pharmacokinetics and reduced the between subject variability in the apparent clearance of oxypurinol (CL/Fm) from 65% to 29%. CL/Fm for patients with normal, mild, moderate and severe renal impairment was 1.8, 0.6, 0.3 and 0.18 l h−1, respectively. Model predictions showed a relationship between plasma oxypurinol and urate concentrations and failure to reach target oxypurinol concentrations using suggested allopurinol dosing guidelines. CONCLUSIONS In conclusion, this first established pharmacokinetic model provides a tool to achieve target oxypurinol plasma concentrations, thereby optimizing the effectiveness and safety of allopurinol therapy in gouty patients with various degrees of renal impairment. PMID:22300439

Method and source for producing a high concentration of positively charged molecular hydrogen or deuterium ions

DOEpatents

Ehlers, Kenneth W.; Leung, Ka-Ngo

1988-01-01

A high concentration of positive molecular ions of hydrogen or deuterium gas is extracted from a positive ion source having a short path length of extracted ions, relative to the mean free path of the gas molecules, to minimize the production of other ion species by collision between the positive ions and gas molecules. The ion source has arrays of permanent magnets to produce a multi-cusp magnetic field in regions remote from the plasma grid and the electron emitters, for largely confining the plasma to the space therebetween. The ion source has a chamber which is short in length, relative to its transverse dimensions, and the electron emitters are at an even shorter distance from the plasma grid, which contains one or more extraction apertures.

[Plasma level and metabolism of vitamin A (Vitadral) in women of reproductive age].

PubMed

Peiker, G; Eckhoff, C; Nau, H

1991-01-01

Using a sensitive HPLC method, plasma concentrations of vitamin A and metabolites were measured from 6 female volunteers who had taken once daily 0.46 mg/kg BW retinol palmitate (Vitadral) for 10 days. The metabolites all-trans- and 13-cis-retinoic acid were increased significantly (2- and 5-fold, resp.) 6 h after the ist intake. 13-cis-4-oxo retinoic acid the 10th intake in the morning of the 10th day (9.22 +/- 2.77 ng/ml, 4-fold increase). The results show continuous increase of retinoic acids, which have to be considered as potential teratogens, after administration of vitamin A. The plasma concentration of retinol itself did not change, whereas only short-term increases were observed for retinol esters.

Quantification and application of a liquid chromatography-tandem mass spectrometric method for the determination of WKYMVm peptide in rat using solid-phase extraction.

PubMed

Lee, Byeong Ill; Park, Min-Ho; Heo, Soon Chul; Park, Yuri; Shin, Seok-Ho; Byeon, Jin-Ju; Kim, Jae Ho; Shin, Young G

2018-03-01

A liquid chromatographic-electrospray ionization-time-of-flight/mass spectrometric (LC-ESI-TOF/MS) method was developed and applied for the determination of WKYMVm peptide in rat plasma to support preclinical pharmacokinetics studies. The method consisted of micro-elution solid-phase extraction (SPE) for sample preparation and LC-ESI-TOF/MS in the positive ion mode for analysis. Phenanthroline (10 mg/mL) was added to rat blood immediately for plasma preparation followed by addition of trace amount of 2 m hydrogen chloride to plasma before SPE for stability of WKYMVm peptide. Then sample preparation using micro-elution SPE was performed with verapamil as an internal standard. A quadratic regression (weighted 1/concentration 2 ), with the equation y = ax 2  + bx + c was used to fit calibration curves over the concentration range of 3.02-2200 ng/mL for WKYMVm peptide. The quantification run met the acceptance criteria of ±25% accuracy and precision values. For quality control samples at 15, 165 and 1820 ng/mL from the quantification experiment, the within-run and the between-run accuracy ranged from 92.5 to 123.4% with precision values ≤15.1% for WKYMVm peptide from the nominal values. This novel LC-ESI-TOF/MS method was successfully applied to evaluate the pharmacokinetics of WKYMVm peptide in rat plasma. Copyright © 2017 John Wiley & Sons, Ltd.

Accurate quantitation of circulating cell-free mitochondrial DNA in plasma by droplet digital PCR.

PubMed

Ye, Wei; Tang, Xiaojun; Liu, Chu; Wen, Chaowei; Li, Wei; Lyu, Jianxin

2017-04-01

To establish a method for accurate quantitation of circulating cell-free mitochondrial DNA (ccf-mtDNA) in plasma by droplet digital PCR (ddPCR), we designed a ddPCR method to determine the copy number of ccf-mtDNA by amplifying mitochondrial ND1 (MT-ND1). To evaluate the sensitivity and specificity of the method, a recombinant pMD18-T plasmid containing MT-ND1 sequences and mtDNA-deleted (ρ 0 ) HeLa cells were used, respectively. Subsequently, different plasma samples were prepared for ddPCR to evaluate the feasibility of detecting plasma ccf-mtDNA. In the results, the ddPCR method showed high sensitivity and specificity. When the DNA was extracted from plasma prior to ddPCR, the ccf-mtDNA copy number was higher than that measured without extraction. This difference was not due to a PCR inhibitor, such as EDTA-Na 2 , an anti-coagulant in plasma, because standard EDTA-Na 2 concentration (5 mM) did not significantly inhibit ddPCR reactions. The difference might be attributable to plasma exosomal mtDNA, which was 4.21 ± 0.38 copies/μL of plasma, accounting for ∼19% of plasma ccf-mtDNA. Therefore, ddPCR can quickly and reliably detect ccf-mtDNA from plasma with a prior DNA extraction step, providing for a more accurate detection of ccf-mtDNA. The direct use of plasma as a template in ddPCR is suitable for the detection of exogenous cell-free nucleic acids within plasma, but not of nucleic acids that have a vesicle-associated form, such as exosomal mtDNA. Graphical Abstract Designs of the present work. *: Module 1, #: Module 2, &: Module 3.

Nicotinamide pharmacokinetics in humans: effect of gastric acid inhibition, comparison of rectal vs oral administration and the use of saliva for drug monitoring.

PubMed Central

Stratford, M. R.; Dennis, M. F.; Hoskin, P.; Phillips, H.; Hodgkiss, R. J.; Rojas, A.

1996-01-01

The effect of inhibiting gastric acid secretion on nicotinamide pharmacokinetics was studied in five volunteers with the intent of reducing the large variations observed previously in the time to and magnitude of peak plasma concentrations. Plasma levels were determined using a standard high-performance liquid chromatography (HPLC) method after an oral dose of 3 g of nicotinamide either alone or preceded by pretreatment with omeprazole. Suppression of gastric acid production had no significant effect on the rate of uptake or on the peak levels achieved. To bypass gastric acidity, the rectal route was also assessed using a suppository in four volunteers and one patient undergoing radiotherapy. Absorption was slow and variable and much lower plasma levels were observed than after oral dosing. Thus, no improvement in the pharmacokinetics of nicotinamide was observed using either of these two approaches. Parallel estimations were made using a novel and non-invasive method for monitoring nicotinamide pharmacokinetics in saliva. A large and variable fraction of the total amount of nicotinamide-related material in saliva was found to be nicotinic acid, a metabolite not normally found in human plasma. This conversion was inhibited by the use of a chlorhexidine mouthwash, indicating that the oral flora was responsible for its production. The time to peak levels of nicotinamide or of nicotinamide plus nicotinic acid in saliva correlated well with that in plasma. However, peak concentrations for nicotinamide alone were significantly lower than in plasma, and very variable, whereas for nicotinamide plus nicotinic acid saliva levels were 20-30% higher, but more consistent. Although there are some practical difficulties in quantitatively handling saliva, the method is very useful for monitoring nicotinamide pharmacokinetics and for assessment of compliance with nicotinamide treatment. PMID:8679452

Simultaneous determination of parecoxib sodium and its active metabolite valdecoxib in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study after intravenous and intramuscular administration.

PubMed

Liu, Meina; Yu, Qiuyang; Li, Ping; Zhu, Meng; Fang, Mingming; Sun, Bingjun; Sun, Mengchi; Sun, Yinghua; Zhang, Peng; He, Zhonggui; Sun, Jin; Wang, Yongjun; Liu, Xiaohong

2016-06-01

In this study, we developed and validated a new, rapid, specific and sensitive ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method to simultaneously determine parecoxib sodium (PX) and its active metabolite, valdecoxib (VX), in rat plasma. Plasma samples were prepared by plasma protein precipitation combined with a liquid-liquid extraction method. The separation was carried out on a Kinetex C18 column (2.1mm×50mm, 2.6μm) with a gradient elution using methanol (A) and a 2mM ammonium acetate aqueous solution (B). The analysis was performed in less than 3min with a flow rate of 0.2mL/min. Ketoprofen was used as an internal standard (IS). Mass spectrometric detection was conducted with a triple quadrupole detector equipped with electrospray ionization in the negative ion mode (ESI(-)) using multiple reaction monitoring (MRM). The calibration curves were linear over the concentration ranges of 5-4000ng/mL for PX and 5-2000ng/mL for VX with all correlation coefficients greater than 0.998. The intra- and inter-day relative standard deviations (RSD) for both analytes were within 15% and the accuracy was within 85-115% at all quality control levels. The mean extraction recoveries for all analytes obtained from three concentrations of QC plasma samples were more than 89.0% efficient. Selectivity, matrix effect, dilution integrity and stability were also validated. The method was successfully used to investigate the pharmacokinetics of PX and VX in rat plasma after intravenous and intramuscular administration of PX. Copyright © 2016 Elsevier B.V. All rights reserved.

Fluorescence Spectrometric Determination of Drugs Containing α-Methylene Sulfone/Sulfonamide Functional Groups Using N-Methylnicotinamide Chloride as a Fluorogenic Agent.

PubMed

Elokely, Khaled M; Eldawy, Mohamed A; Elkersh, Mohamed A; El-Moselhy, Tarek F

2011-01-01

A simple spectrofluorometric method has been developed, adapted, and validated for the quantitative estimation of drugs containing α-methylene sulfone/sulfonamide functional groups using N(1)-methylnicotinamide chloride (NMNCl) as fluorogenic agent. The proposed method has been applied successfully to the determination of methyl sulfonyl methane (MSM) (1), tinidazole (2), rofecoxib (3), and nimesulide (4) in pure forms, laboratory-prepared mixtures, pharmaceutical dosage forms, spiked human plasma samples, and in volunteer's blood. The method showed linearity over concentration ranging from 1 to 150 μg/mL, 10 to 1000 ng/mL, 1 to 1800 ng/mL, and 30 to 2100 ng/mL for standard solutions of 1, 2, 3, and 4, respectively, and over concentration ranging from 5 to 150 μg/mL, 10 to 1000 ng/mL, 10 to 1700 ng/mL, and 30 to 2350 ng/mL in spiked human plasma samples of 1, 2, 3, and 4, respectively. The method showed good accuracy, specificity, and precision in both laboratory-prepared mixtures and in spiked human plasma samples. The proposed method is simple, does not need sophisticated instruments, and is suitable for quality control application, bioavailability, and bioequivalency studies. Besides, its detection limits are comparable to other sophisticated chromatographic methods.

Development and validation of a method for gefitinib quantification in dried blood spots using liquid chromatography-tandem mass spectrometry: Application to finger-prick clinical blood samples of patients with non-small cell lung cancer.

PubMed

Irie, Kei; Shobu, Saori; Hiratsuji, Seika; Yamasaki, Yuta; Nanjo, Shigeki; Kokan, Chiyuki; Hata, Akito; Kaji, Reiko; Masago, Katsuhiro; Fujita, Shiro; Okada, Yutaka; Katakami, Nobuyuki; Fukushima, Shoji

2018-06-15

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of gefitinib in dried blood spots (DBSs). Gefitinib was extracted with methanol from DBS of 3 mm in diameter and detected using a triple quadrupole mass spectrometer. The method was validated by evaluating its precision, accuracy, selectivity, carryover, matrix effect, recovery, and stability. For clinical validation, paired finger-prick DBS and plasma concentrations were compared for 10 patients with non-small cell lung cancer (NSCLC) taking gefitinib. The calibration linear range was 37.5-2400 ng/mL (coefficient of determination [R 2 ] = 0.99), encompassing the therapeutic concentrations of gefitinib. The accuracy and precision were within 15% of the quality control (QC) concentrations of 80, 200, and 2000 ng/mL. The lower limit of quantification was determined to be 40 ng/mL. Gefitinib was stable in DBSs for up to 5 months at room temperature and -20 °C, and at 40 °C for 24 h. A good correlation was observed between the gefitinib levels measured by the DBS method and plasma concentrations (R 2  = 0.99). This method provides a simple, fast, and accurate approach to the quantitative analysis of gefitinib in finger-prick DBSs. The method would be useful for minimally invasive evaluation of the clinical gefitinib blood concentration. Copyright © 2018 Elsevier B.V. All rights reserved.

Nicotine Metabolite Ratio (3-hydroxycotinine/cotinine) in Plasma and Urine by Different Analytical Methods and Laboratories: Implications for Clinical Implementation

PubMed Central

Tanner, Julie-Anne; Novalen, Maria; Jatlow, Peter; Huestis, Marilyn A.; Murphy, Sharon E.; Kaprio, Jaakko; Kankaanpää, Aino; Galanti, Laurence; Stefan, Cristiana; George, Tony P.; Benowitz, Neal L.; Lerman, Caryn; Tyndale, Rachel F.

2015-01-01

Background The highly genetically variable enzyme CYP2A6 metabolizes nicotine to cotinine (COT) and COT to trans-3′-hydroxycotinine (3HC). The nicotine metabolite ratio (NMR, 3HC/COT) is commonly used as a biomarker of CYP2A6 enzymatic activity, rate of nicotine metabolism, and total nicotine clearance; NMR is associated with numerous smoking phenotypes, including smoking cessation. Our objective was to investigate the impact of different measurement methods, at different sites, on plasma and urinary NMR measures from ad libitum smokers. Methods Plasma (n=35) and urine (n=35) samples were sent to eight different laboratories, which employed similar and different methods of COT and 3HC measurements to derive the NMR. We used Bland-Altman analysis to assess agreement, and Pearson correlations to evaluate associations, between NMR measured by different methods. Results Measures of plasma NMR were in strong agreement between methods according to Bland-Altman analysis (ratios 0.82–1.16) and were highly correlated (all Pearson r>0.96, P<0.0001). Measures of urinary NMR were in relatively weaker agreement (ratios 0.62–1.71) and less strongly correlated (Pearson r values of 0.66–0.98, P<0.0001) between different methods. Plasma and urinary COT and 3HC concentrations, while weaker than NMR, also showed good agreement in plasma, which was better than in urine, as was observed for NMR. Conclusions Plasma is a very reliable biological source for the determination of NMR, robust to differences in these analytical protocols or assessment site. Impact Together this indicates a reduced need for differential interpretation of plasma NMR results based on the approach used, allowing for direct comparison of different studies. PMID:26014804

Electrolyte and plasma changes after ingestion of pickle juice, water, and a common carbohydrate-electrolyte solution.

PubMed

Miller, Kevin C; Mack, Gary; Knight, Kenneth L

2009-01-01

Health care professionals advocate that athletes who are susceptible to exercise-associated muscle cramps (EAMCs) should moderately increase their fluid and electrolyte intake by drinking sport drinks. Some clinicians have also claimed drinking small volumes of pickle juice effectively relieves acute EAMCs, often alleviating them within 35 seconds. Others fear ingesting pickle juice will enhance dehydration-induced hypertonicity, thereby prolonging dehydration. To determine if ingesting small quantities of pickle juice, a carbohydrate-electrolyte (CHO-e) drink, or water increases plasma electrolytes or other selected plasma variables. Crossover study. Exercise physiology laboratory. Nine euhydrated, healthy men (age = 25 +/- 2 years, height = 179.4 +/- 7.2 cm, mass = 86.3 +/- 15.9 kg) completed the study. Resting blood samples were collected preingestion (-0.5 minutes); immediately postingestion (0 minutes); and at 1, 5, 10, 15, 20, 25, 30, 45, and 60 minutes postingestion of 1 mL/kg body mass of pickle juice, CHO-e drink, or tap water. Plasma sodium concentration, plasma magnesium concentration, plasma calcium concentration, plasma potassium concentration, plasma osmolality, and changes in plasma volume were analyzed. Urine specific gravity, osmolality, and volume were also measured to characterize hydration status. Mean fluid intake was 86.3 +/- 16.7 mL. Plasma sodium concentration, plasma magnesium concentration, plasma calcium concentration, plasma osmolality, and plasma volume did not change during the 60 minutes after ingestion of each fluid (P >or= .05). Water ingestion slightly decreased plasma potassium concentration at 60 minutes (0.21 +/- 0.14 mg/dL [0.21 +/- 0.14 mmol/L]; P

Simultaneous assay of multiple antibiotics in human plasma by LC-MS/MS: importance of optimizing formic acid concentration.

PubMed

Chen, Feng; Hu, Zhe-Yi; Laizure, S Casey; Hudson, Joanna Q

2017-03-01

Optimal dosing of antibiotics in critically ill patients is complicated by the development of resistant organisms requiring treatment with multiple antibiotics and alterations in systemic exposure due to diseases and extracorporeal drug removal. Developing guidelines for optimal antibiotic dosing is an important therapeutic goal requiring robust analytical methods to simultaneously measure multiple antibiotics. An LC-MS/MS assay using protein precipitation for cleanup followed by a 6-min gradient separation was developed to simultaneously determine five antibiotics in human plasma. The precision and accuracy were within the 15% acceptance range. The formic acid concentration was an important determinant of signal intensity, peak shape and matrix effects. The method was designed to be simple and successfully applied to a clinical pharmacokinetic study.

Improving the sensitivity and specificity of a bioanalytical assay for the measurement of certolizumab pegol.

PubMed

Smeraglia, John; Silva, John-Paul; Jones, Kieran

2017-08-01

In order to evaluate placental transfer of certolizumab pegol (CZP), a more sensitive and selective bioanalytical assay was required to accurately measure low CZP concentrations in infant and umbilical cord blood. Results & methodology: A new electrochemiluminescence immunoassay was developed to measure CZP levels in human plasma. Validation experiments demonstrated improved selectivity (no matrix interference observed) and a detection range of 0.032-5.0 μg/ml. Accuracy and precision met acceptance criteria (mean total error ≤20.8%). Dilution linearity and sample stability were acceptable and sufficient to support the method. The electrochemiluminescence immunoassay was validated for measuring low CZP concentrations in human plasma. The method demonstrated a more than tenfold increase in sensitivity compared with previous assays, and improved selectivity for intact CZP.

Sensitive liquid chromatography-tandem mass spectrometry method for the simultaneous determination of paracetamol and guaifenesin in human plasma.

PubMed

Chen, Xiaoyan; Huang, Jia; Kong, Zhang; Zhong, Dafang

2005-03-25

A rapid and sensitive method for the simultaneous determination of paracetamol and guaifenesin in human plasma was developed and validated, using high-performance liquid chromatographic separation with tandem mass spectrometric detection. After extracted from plasma samples by diethyl ether-dichloromethane (3:2, v/v), the analytes and internal standard osalmide were chromatographed on a C18 column. Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI). The method was linear in the concentration range of 0.05-20.0 microg/ml for paracetamol and 5.0-2000.0 ng/ml for guaifenesin. The intra- and inter-day precision was within 14% for both paracetamol and guaifenesin. The assay accuracy was within +/-2.4% for the analytes. This is the first assay method described for the simultaneous determination of paracetamol and guaifenesin in plasma using one chromatographic run. The method was successfully employed in a pharmacokinetic study after an oral administration of a multicomponent formulation, containing 650 mg paracetamol, 200 mg guaifenesin, 60 mg pseudoephedrine and 20 mg dextrorphan.

Sensitive spectrofluorimetric determination of tizanidine in pharmaceutical preparations, human plasma and urine through derivatization with dansyl chloride.

PubMed

Ulu, Sevgi Tatar

2012-01-01

A sensitive spectrofluorimetric method was developed for the determination of tizanidine in human plasma, urine and pharmaceutical preparations. The method is based on reaction of tizanidine with 1-dimethylaminonaphthalene-5-sulphonyl chloride (dansyl chloride) in an alkaline medium to form a highly fluorescent derivative that was measured at 511 nm after excitation at 383 nm. The different experimental parameters affecting the fluorescence intensity of tizanidine was carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the ranges 50-500 and 20-300 ng/mL for plasma and urine, respectively, detection limits of 1.81 and 0.54 ng/mL and quantification limits of 5.43 and 1.62 ng/mL for plasma and urine, respectively. The method presents good performance in terms of linearity, detection and quantification limits, precision, accuracy and specificity. The proposed method was successfully applied for the determination of tizanidine in pharmaceutical preparations. The results obtained were compared with a reference method, using t- and F-tests. Copyright © 2011 John Wiley & Sons, Ltd.

A MODIFIED LOW COST COLOURIMETRIC METHOD FOR PARACETAMOL (ACETAMINOPHEN) MEASUREMENT IN PLASMA

PubMed Central

Shihana, Fathima; Dissanayake, Dhammika Menike; Dargan, Paul Ivor; Dawson, Andrew Hamilton

2011-01-01

Background Despite a significant increase in the number of patients with paracetamol poisoning in the developing world, plasma paracetamol assays are not widely available. The purpose of this study was to assess a low cost modified colorimetric paracetamol assay that has the potential to be performed in small laboratories with restricted resources. Methods The paracetamol assay used in this study was based on the Glynn and Kendal colorimetric method with a few modifications in order to decrease the production of nitrous gas and thereby reduce infrastructure costs. Preliminary validation studies were performed using spiked aqueous samples with known concentrations of paracetamol. Subsequently, the results from the colorimetric method for 114 stored clinical samples from patients with paracetamol poisoning were compared with those from the current gold-standard high-performance liquid chromatography (HPLC) method. A prospective survey, assessing the clinical use of the paracetamol assay, was performed on all patients with paracetamol poisoning attending the Peradeniya General Hospital, Sri Lanka over a ten-month period. Results The recovery study showed an excellent correlation (r2 >0.998) for paracetamol concentrations from 25- 400 mg/l. The final yellow colour was stable for at least 10 minutes at room temperature. There was also excellent correlation with the HPLC method (r2=0.9758). In the clinical cohort study, use of the antidote N-acetylcysteine was avoided in over a third of patients who had a plasma paracetamol concentration measured. The cost of consumables used per assay was $0.50 (US). Conclusions This colorimetric paracetamol assay is reliable and accurate and can be performed rapidly, easily and economically. Use of this assay in resource poor clinical settings has the potential to have a significant clinical and economic impact on the management of paracetamol poisoning. PMID:20095813

Development and Validation of a Rapid 13C6-Glucose Isotope Dilution UPLC-MRM Mass Spectrometry Method for Use in Determining System Accuracy and Performance of Blood Glucose Monitoring Devices

PubMed Central

Matsunami, Risë K.; Angelides, Kimon; Engler, David A.

2015-01-01

Background: There is currently considerable discussion about the accuracy of blood glucose concentrations determined by personal blood glucose monitoring systems (BGMS). To date, the FDA has allowed new BGMS to demonstrate accuracy in reference to other glucose measurement systems that use the same or similar enzymatic-based methods to determine glucose concentration. These types of reference measurement procedures are only comparative in nature and are subject to the same potential sources of error in measurement and system perturbations as the device under evaluation. It would be ideal to have a completely orthogonal primary method that could serve as a true standard reference measurement procedure for establishing the accuracy of new BGMS. Methods: An isotope-dilution liquid chromatography/mass spectrometry (ID-UPLC-MRM) assay was developed using 13C6-glucose as a stable isotope analogue to specifically measure glucose concentration in human plasma, and validated for use against NIST standard reference materials, and against fresh isolates of whole blood and plasma into which exogenous glucose had been spiked. Assay performance was quantified to NIST-traceable dry weight measures for both glucose and 13C6-glucose. Results: The newly developed assay method was shown to be rapid, highly specific, sensitive, accurate, and precise for measuring plasma glucose levels. The assay displayed sufficient dynamic range and linearity to measure across the range of both normal and diabetic blood glucose levels. Assay performance was measured to within the same uncertainty levels (<1%) as the NIST definitive method for glucose measurement in human serum. Conclusions: The newly developed ID UPLC-MRM assay can serve as a validated reference measurement procedure to which new BGMS can be assessed for glucose measurement performance. PMID:25986627

Determining the fatty acid composition in plasma and tissues as fatty acid methyl esters using gas chromatography – a comparison of different derivatization and extraction procedures.

PubMed

Ostermann, Annika I; Müller, Maike; Willenberg, Ina; Schebb, Nils Helge

2014-12-01

Analysis of the fatty acid (FA) composition in biological samples is commonly carried out using gas liquid chromatography (GC) after transesterification to volatile FA methyl esters (FAME). We compared the efficacy of six frequently used protocols for derivatization of different lipid classes as well as for plasma and tissue samples. Transesterification with trimethylsulfonium hydroxide (TMSH) led to insufficient derivatization efficacies for polyunsaturated FAs (PUFA, <50%). Derivatization in presence of potassium hydroxide (KOH) failed at derivatizing free FAs (FFAs). Boron trifluoride (BF3) 7% in hexane/MeOH (1:1) was insufficient for the transesterification of cholesterol ester (CE) as well as triacylglycerols (TGs). In contrast, methanolic hydrochloric acid (HCl) as well as a combination of BF3 with methanolic sodium hydroxide (NaOH+BF3) were suitable for the derivatization of FFAs, polar lipids, TGs, and CEs (derivatization rate >80% for all tested lipids). Regarding plasma samples, all methods led to an overall similar relative FA pattern. However, significant differences were observed, for example, for the relative amount of EPA+DHA (n3-index). Absolute FA plasma concentrations differed considerably among the methods, with low yields for KOH and BF3. We also demonstrate that lipid extraction with tert-butyl methyl ether/methanol (MTBE/MeOH) is as efficient as the classical method according to Bligh and Dyer, making it possible to replace (environmentally) toxic chloroform.We conclude that HCl-catalyzed derivatization in combination with MeOH/MTBE extraction is the most appropriate among the methods tested for the analysis of FA concentrations and FA pattern in small biological samples. A detailed protocol for the analysis of plasma and tissues is included in this article.

Development and validation of a high-performance liquid chromatography-tandem mass spectrometry assay quantifying vemurafenib in human plasma.

PubMed

Nijenhuis, C M; Rosing, H; Schellens, J H M; Beijnen, J H

2014-01-01

Vemurafenib is an inhibitor of mutated serine/threonine-protein kinase B-Raf (BRAF) and is registered as Zelboraf(®) for the treatment of adult patients with BRAF V600 mutation-positive unresectable or metastatic melanoma. To support Therapeutic Drug Monitoring (TDM) and clinical trials, we developed and validated a method for the quantification of vemurafenib in human plasma. Additionally two LC-MS systems with different detectors were tested: the TSQ Quantum Ultra and the API3000. Human plasma samples were collected in the clinic and stored at nominally -20°C. Vemurafenib was isolated from plasma by liquid-liquid extraction, separated on a C18 column with gradient elution, and analysed with triple quadrupole mass spectrometry in positive-ion mode. A stable isotope was used as internal standard for the quantification. Ranging from 1 to 100μg/ml the assay was linear with correlation coefficients (r(2)) of 0.9985 or better. Inter-assay and intra-assay accuracies were within ±7.6% of the nominal concentration; inter-assay and intra-assay precision were within ≤9.3% of the nominal concentration. In addition all results were within the acceptance criteria of the US FDA and the latest EMA guidelines for method validation for both MS detectors. In conclusion, the presented analytical method for vemurafenib in human plasma was successfully validated and the performance of the two LC-MS systems for this assay was comparable. In addition the method was successfully applied to evaluate the pharmacokinetic quantification of vemurafenib in cancer patients treated with vemurafenib. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral study of interaction between chondroitin sulfate and nanoparticles and its application in quantitative analysis

NASA Astrophysics Data System (ADS)

Ma, Yi; Wei, Maojie; Zhang, Xiao; Zhao, Ting; Liu, Xiumei; Zhou, Guanglian

2016-01-01

In this work, the interaction between chondroitin sulfate (CS) and gold nanoparticles (GNPs) and silver nanoparticles (SNPs) was characterized for the first time. Plasma resonance scattering (PRS) and plasma resonance absorption (PRA) were used to investigate the characteristics of their spectrum. The results suggested that the CS with negative charge could interact with metal nanoparticles with negative charge and the adsorption of CS on the surface of SNPs was more regular than that of GNPs. The resonance scattering spectra also further confirmed the interaction between CS and SNPs. A new method for detection of CS based on the interaction was developed. CS concentrations in the range of 0.02-3.5 μg/mL were proportional to the decreases of absorbance of SNPs. Compared with other reported methods, the proposed method is simple and workable without complex process, high consumption and expensive equipments. The developed method was applied to the determination of the CS contents from different biological origins and the results were compared with those obtained by the method of Chinese Pharmacopeia. The effects of matrix in plasma and other glycosaminoglycans on the determination of CS were also investigated. The results showed that a small quantity of blood plasma had no effect on the determination of CS and when the concentration ratio of CS to heparin was more than 10:1, the influence of heparin on the detection of CS could be ignored. This work gave a specific research direction for the detection of CS in the presence of metal nanoparticles.

A solid phase extraction-liquid chromatographic-tandem mass spectrometry method for determination of concentrations of GDC-0941, a small molecule class I phosphatidylinositide 3-kinase inhibitor, to support clinical development.

PubMed

Ding, X; Morrison, G; Dean, B; Hop, C E C A; Tobler, L; Percey, S; Meng, M; Reuschel, S; West, D A; Holden, S; Ware, J A

2012-03-05

A solid phase extraction (SPE) liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the determination of GDC-0941 concentrations in human plasma has been developed and validated to support clinical development. An Oasis MCX 10mg 96-well SPE plate was used to extract plasma samples (50 μL) and the resulting extracts were analyzed using reverse-phase chromatography and mass spectrometer coupled with a turbo-ionspray interface. The method was validated over the calibration curve range 0.500-500 ng/mL with linear regression and 1/x(2) weighting. Within-run relative standard deviation (%RSD) ranged from 1.5 to 11.5%, while the between-run %RSD varied from 0.0 to 4.4%. The accuracy ranged from 96.0% to 110.0% of nominal for within-run and 98.0% to 108.0% of nominal for between-run at all concentrations including the LLOQ quality control at 0.500 ng/mL. Extraction recovery of GDC-0941 was between 79.0% and 86.2%. Stability of GDC-0941 was established in human plasma for 602 days at -70 °C and 598 days at -20°C, respectively, and established in reconstituted sample extracts for 167 h when stored at room temperature. Internal standard normalized matrix factor was 1.1, demonstrating that the use of the stable-labeled internal standard GDC-0941-d(8) effectively compensated observed matrix effect and resulting in no adverse impact on the quality of the data produced. This assay was used for the determination of GDC-0941 human plasma concentrations over a sufficient time period to determine pharmacokinetic parameters at relevant clinical doses. Copyright © 2011 Elsevier B.V. All rights reserved.

Quantitative measurement of betaine and free choline in plasma, cereals and cereal products by isotope dilution LC-MS/MS.

PubMed

Bruce, Stephen J; Guy, Philippe A; Rezzi, Serge; Ross, Alastair B

2010-02-24

Betaine and choline are important components of the one-carbon metabolism cycle, linked with the amino acid homocysteine and lipid metabolism. Analyses of broad ranges of foods point to cereal based foods being important sources of betaine and choline, however to date there has been no detailed analysis of these compounds in cereal flours or cereal products. An analytical method based on optimization of an existing extraction followed by LC-MS/MS analysis was used to analyze 47 plasma samples, 32 cereal flours and cereal fractions, and 51 cereal products. For the method validation LLOQ, recovery, inter- and intraday repeatability were all performed. Whole-grain wheat and rye flours, and products based on these were the best whole cereal sources of betaine (747-1508 microg/g) and to a lesser extent choline (76-159 microg/g), while the bran fraction contained the highest concentrations of betaine and free-choline (2350-2899 microg/g and 366-384 microg/g respectively). Refined wheat flour and products contained lower concentrations, while rice and maize contained only very low and no detectable amounts of betaine respectively (0-10 microg/g), and low amounts of free-choline (<31 microg/g). These results were mirrored in cereal products analyzed, with whole-grain wheat or rye-based cereal products having the highest concentrations of the two metabolites. Plasma concentrations for betaine and free-choline in a group of 47 subjects ranged from 15.2-66.3 and 9.8-18.5 micromol/L respectively, within the range of previous reports. This LC-MS/MS method can be used to rapidly and sensitively quantify betaine and free-choline in plasma and cereal products. Whole-grain cereal products and products containing cereal bran appear to be excellent dietary sources of betaine and free-choline.

Sensitive determination of three aconitum alkaloids and their metabolites in human plasma by matrix solid-phase dispersion with vortex-assisted dispersive liquid-liquid microextraction and HPLC with diode array detection.

PubMed

Wang, Xiaozhong; Li, Xuwen; Li, Lanjie; Li, Min; Liu, Ying; Wu, Qian; Li, Peng; Jin, Yongri

2016-05-01

A simple and sensitive method for determination of three aconitum alkaloids and their metabolites in human plasma was developed using matrix solid-phase dispersion combined with vortex-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection. The plasma sample was directly purified by matrix solid-phase dispersion and the eluate obtained was concentrated and further clarified by vortex-assisted dispersive liquid-liquid microextraction. Some important parameters affecting the extraction efficiency, such as type and amount of dispersing sorbent, type and volume of elution solvent, type and volume of extraction solvent, salt concentration as well as sample solution pH, were investigated in detail. Under optimal conditions, the proposed method has good repeatability and reproducibility with intraday and interday relative standard deviations lower than 5.44 and 5.75%, respectively. The recoveries of the aconitum alkaloids ranged from 73.81 to 101.82%, and the detection limits were achieved within the range of 1.6-2.1 ng/mL. The proposed method offered the advantages of good applicability, sensitivity, simplicity, and feasibility, which makes it suitable for the determination of trace amounts of aconitum alkaloids in human plasma samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cefazolin pharmacokinetics in cats under surgical conditions.

PubMed

Albarellos, Gabriela A; Montoya, Laura; Passini, Sabrina M; Lupi, Martín P; Lorenzini, Paula M; Landoni, María F

2017-10-01

Objectives The aim of this study was to determine the plasma pharmacokinetic profile, tissue concentrations and urine elimination of cefazolin in cats under surgical conditions after a single intravenous dose of 20 mg/kg. Methods Intravenous cefazolin (20 mg/kg) was administered to nine young mixed-breed cats 30 mins before they underwent surgical procedures (ovariectomy or orchiectomy). After antibiotic administration, samples from blood, some tissues and urine were taken. Cefazolin concentrations were determined in all biological matrices and pharmacokinetic parameters were estimated. Results Initial plasma concentrations were high (C p(0) , 134.80 ± 40.54 µg/ml), with fast and moderately wide distribution (distribution half-life [t ½(d) ] 0.16 ± 0.15 h; volume of distribution at steady state [V (d[ss]) ] 0.29 ± 0.10 l/kg) and rapid elimination (body clearance [Cl B ], 0.21 ± 0.06 l/h/kg; elimination half-life [t ½ ], 1.18 ± 0.27 h; mean residence time 1.42 ± 0.36 h). Thirty to 60 mins after intravenous administration, cefazolin tissue concentrations ranged from 9.24 µg/ml (subcutaneous tissue) to 26.44 µg/ml (ovary). The tissue/plasma concentration ratio ranged from 0.18 (muscle) to 0.58 (ovary). Cefazolin urine concentrations were high with 84.2% of the administered dose being eliminated in the first 6 h postadministration. Conclusions and relevance Cefazolin plasma concentrations remained above a minimum inhibitory concentration of ⩽2 µg/ml up to 4 h in all the studied cats. This suggests that a single intravenous dose of 20 mg/kg cefazolin would be adequate for perioperative prophylactic use in cats.

LC-UV/MS methods for the analysis of prochelator - boronyl salicylaldehyde isonicotinoyl hydrazone (BSIH) and its active chelator salicylaldehyde isonicotinoyl hydrazone (SIH)

PubMed Central

Bureš, Jan; Jansová, Hana; Stariat, Ján; Filipský, Tomáš; Mladěnka, Přemysl; Šimůnek, Tomáš; Kučera, Radim; Klimeš, Jiří; Wang, Qin; Franz, Katherine J.; Kovaříková, Petra

2015-01-01

Salicylaldehyde isonicotinoyl hydrazone (SIH) is an intracellular iron chelator with well documented potential to protect against oxidative injury both in vitro and in vivo. However, it suffers from short biological half-life caused by fast hydrolysis of the hydrazone bond. Recently, a concept of boronate prochelators has been introduced as a strategy that might overcome these limitations. This study presents two complementary analytical methods for detecting the prochelator BSIH (boronyl salicylaldehyde isonicotinoyl hydrazone) along with its active metal-binding chelator SIH in different solution matrices and concentration ranges. An LC-UV method for determination of BSIH and SIH in buffer and cell culture medium was validated over concentrations of 7 – 115 and 4 – 115 μM, respectively, and applied to BSIH activation experiments in vitro. An LC-MS assay was validated for quantification of BSIH and SIH in plasma over the concentration range of 0.06 – 23 and 0.24 – 23 μM, respectively, and applied to stability studies in plasma in vitro as well as analysis of plasma taken after i.v. administration of BSIH to rats. A Zorbax-RP bonus column and mobile phases containing either phosphate buffer with EDTA or ammonium formate and methanol/acetonitrile mixture provided suitable conditions for the LC-UV and LC-MS analysis, respectively. Samples were diluted or precipitated with methanol prior to analysis. These separative analytical techniques establish the first validated protocols to investigate BSIH activation by hydrogen peroxide in multiple matrices, directly compare the stabilities of the prochelator and chelator in plasma, and provide the first basic pharmacokinetic data of this prochelator. Experiments reveal that BSIH is stable in all media tested and is partially converted to SIH by H2O2. The observed integrity of BSIH in plasma samples from the in vivo study suggest that the concept of prochelation might be a promising strategy for further development of aroylhydrazone cytoprotective agents. PMID:25527982

Acamprosate determinations in plasma and cerebrospinal fluid after multiple dosing measured by liquid chromatography-mass spectroscopy: a pharmacokinetic study in healthy volunteers.

PubMed

Hammarberg, Anders; Beck, Olof; Eksborg, Staffan; Jayaram-Lindström, Nitya; Lindefeldt, Annika; Andersson, Maria; Brundin, Lou; Reid, Malcolm S; Franck, Johan

2010-08-01

The central nervous system-active medication acamprosate has been shown to modulate alcohol-related behavior in both preclinical and clinical studies. Although commonly used in the treatment of alcohol dependence, there are still unanswered questions concerning the pharmacokinetic properties of acamprosate. The aims of the present study were to 1) to validate liquid chromatography-mass spectrometry as a method to study the presence of acamprosate in plasma and cerebrospinal fluid (CSF) in humans; and 2) validate previous results on clinically important pharmacokinetic data for acamprosate. In an open label, single-site design, 13 healthy males and females were recruited to 22 days of oral acamprosate treatment (1998 mg/day). Subjects provided in all 256 plasma samples for analysis at regular intervals at Day 1, 7, 14, and 22 of treatment. On Day 22, subjects also left a sample of CSF for measurement of acamprosate. The results showed that steady-state level of acamprosate was accomplished within 5 days after the start of treatment and remained fairly stable for 2 to 3 days after termination of treatment. Variations in plasma concentrations corresponded to earlier studies and did not exceed those for comparable pharmacotherapeutic agents. Acamprosate concentrations in the CSF were below the limit of quantification, ie, estimated concentrations between 9 and 33 ng/mL. Plasma concentrations were more than 25 times higher than in lumbar CSF. The low CSF levels seen after 3 weeks of treatment may provide an explanation to the delay in therapeutic effect noticed in treatment studies on acamprosate. A longer duration of treatment might be necessary to obtain clinically significant brain levels of acamprosate. In summary, the present study validated liquid chromatography-mass spectrometry as a method for assessment of compliance to acamprosate treatment. Furthermore, the results suggest that the mechanism of action of acamprosate needs to be further explored with regard to the peripheral actions of the drug.

[Determination of isoniazide concentration in pleural effusion and its pleural permeability in patients with tuberculous pleurisy].

PubMed

Liu, Yuan; Zhang, Qing; Zhang, Junfeng; Huang, Guohua; Zhu, Shunfang; Liu, Sijia; Li, Guofeng

2012-05-01

To establish a high-performance liquid chromatography (HPLC)-based method for determining isoniazide concentration in pleural effusion and plasma of patients with tuberculous pleurisy, and evaluate the permeability of isoniazide from blood into pleural effusion. We collected pleural effusion from 15 patients with tuberculous pleurisy 2 h after administration 300 mg isoniazide in the morning of day 1. Pleural effusion and plasma were obtained 2 h after isoniazide administration on day 3. Isoniazide concentration was measured using HPLC, and the penetration rate of isoniazide in pleural effusion was calculated. Isoniazide concentration in the pleural effusion averaged 1.156∓1.190 µg/ml in the 15 patients at 2 h after isoniazide administration on day 1. On day 3, isoniazide concentration was 1.920∓1.294 µg/ml in the pleural effusion and 2.445∓1.463 µg/ml in the plasma, and the mean penetration rate of isoniazide from blood into the pleural effusion was 86.0%. As isoniazide has a high penetration rate into the pleural effusion in most patients, continuous oral administration of isoniazid has been sufficient to achieve an effective treatment concentration, and intrapleural injection of isoniazide may seem unnecessary for non-drug-resistant tuberculosis pleurisy.

Comparison of two methods using plasma triglyceride concentration as a surrogate estimate of insulin action in nondiabetic subjects: triglycerides × glucose versus triglyceride/high-density lipoprotein cholesterol.

PubMed

Abbasi, Fahim; Reaven, Gerald M

2011-12-01

The objective was to compare relationships between insulin-mediated glucose uptake and surrogate estimates of insulin action, particularly those using fasting triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) concentrations. Insulin-mediated glucose uptake was quantified by determining the steady-state plasma glucose (SSPG) concentration during the insulin suppression test in 455 nondiabetic subjects. Fasting TG, HDL-C, glucose, and insulin concentrations were measured; and calculations were made of the following: (1) plasma concentration ratio of TG/HDL-C, (2) TG × fasting glucose (TyG index), (3) homeostasis model assessment of insulin resistance, and (4) insulin area under the curve (insulin-AUC) during a glucose tolerance test. Insulin-AUC correlated most closely with SSPG (r ∼ 0.75, P < .001), with lesser but comparable correlations between SSPG and TG/HDL-C ratio, TyG index, homeostasis model assessment of insulin resistance, and fasting TG and insulin (r ∼ 0.60, P < .001). Calculations of TG/HDL-C ratio and TyG index correlated with SSPG concentration to a similar degree, and the relationships were comparable to estimates using fasting insulin. The strongest relationship was between SSPG and insulin-AUC. Copyright © 2011 Elsevier Inc. All rights reserved.

Studies on the Safety of DDVP for the Disinsection of Commercial Aircraft*

PubMed Central

Witter, Robert F.; Gaines, Thomas B.; Short, J. Gordon; Sedlak, V. A.; Maddock, D. R.

1961-01-01

There is a need for a more effective method for the disinsection of intercontinental aircraft. A study was made of the possible toxic hazard associated with a new method of disinsection using DDVP vapour (O,O-dimethyl-2,2-dichlorovinyl phosphate) as the insecticidal agent. In these experiments, men and monkeys were exposed four times over one- or two-hour periods for a total of 4-8 hours to DDVP vapour in a simulated aircraft cabin. The concentration of DDVP was higher and the exposure periods were longer than those planned for use in disinsection. Concentrations up to 0.7 μg per litre of air produced no effect on the cholinesterase of men or monkeys. It was found that a concentration of DDVP of 0.9-3.5 μg per litre of air caused a slight decrease in plasma cholinesterase of the men and the monkeys. At a DDVP concentration of 7.5-17.9 μg per litre, monkeys exhibited a marked drop in red cell and plasma cholinesterase and showed miosis, but no other signs of poisoning. PMID:13786106

A liquid chromatography/tandem mass spectrometry assay for the analysis of atomoxetine in human plasma and in vitro cellular samples

PubMed Central

Appel, David I.; Brinda, Bryan; Markowitz, John S.; Newcorn, Jeffrey H.; Zhu, Hao-Jie

2012-01-01

A simple, rapid and sensitive method for quantification of atomoxetine by liquid chromatography- tandem mass spectrometry (LC-MS/MS) was developed. This assay represents the first LC-MS/MS quantification method for atomoxetine utilizing electrospray ionization. Deuterated atomoxetine (d3-atomoxetine) was adopted as the internal standard. Direct protein precipitation was utilized for sample preparation. This method was validated for both human plasma and in vitro cellular samples. The lower limit of quantification was 3 ng/ml and 10 nM for human plasma and cellular samples, respectively. The calibration curves were linear within the ranges of 3 ng/ml to 900 ng/ml and 10 nM to 10 μM for human plasma and cellular samples, respectively (r2 > 0.999). The intra- and inter-day assay accuracy and precision were evaluated using quality control samples at 3 different concentrations in both human plasma and cellular lysate. Sample run stability, assay selectivity, matrix effect, and recovery were also successfully demonstrated. The present assay is superior to previously published LC-MS and LC-MS/MS methods in terms of sensitivity or the simplicity of sample preparation. This assay is applicable to the analysis of atomoxetine in both human plasma and in vitro cellular samples. PMID:22275222

Automated determination of polyamines by high-performance liquid chromatography with simple sample preparation.

PubMed

van Eijk, H M; Rooyakkers, D R; Deutz, N E

1996-04-12

Recently, a new fully endcapped reversed-phase packing material, Inertsil, was introduced, especially suitable for the determination of basic compounds. We used this packing material to separate ophthaldialdehyde (OPA) derivatives of amino acid derivatives completely from the OPA derivatives of spermine (SPM), spermidine (SPD), putrescine (PUT) and cadaverine (CAD). The obtained separation made the commonly used off-line extraction procedure redundant and thus an on-line sample clean-up was introduced. This enabled automation of the procedure resulting in a better reproducibility and a more efficient use of equipment. Furthermore, no studies are required to determine the extraction recovery. The present method has a cycle time of 30 min. A linear response for each polyamine was found up to 250 pmol, with an R2 ranging from 0.9981 (SPM) to 0.9998 (CAD). The limit of detection, calculated at a signal-to-noise ratio of 3, was 0.1 pmol, corresponding to a plasma concentration of 0.1 mumol/l. The coefficient of variation (C.V.) for the peak area was below 3% and for retention times below 0.5% (n = 15). In order to evaluate the applicability of the method, three different types of sample were chromatographed, e.g. urine (obtained from healthy human volunteers), pig plasma and sulfosalicylic acid homogenates of pig intestine biopsies. Tissue homogenates and urine-specimen could easily be quantitated, while plasma concentrations were just above the limit of detection, resulting in a plasma C.V. ranging from 4.8% (SPM) to 13.6% (SPD) and a tissue C.V. ranging from 2.1% (SPM) to 8.5% (CAD), The urinary C.V.s were not determined. In conclusion, the present method provides an easy way to measure polyamine concentrations for most applications.

Plasma levels of trimethylamine-N-oxide are confounded by impaired kidney function and poor metabolic control.

PubMed

Mueller, Daniel M; Allenspach, Martina; Othman, Alaa; Saely, Christoph H; Muendlein, Axel; Vonbank, Alexander; Drexel, Heinz; von Eckardstein, Arnold

2015-12-01

After ingestion of phosphatidylcholine, l-carnitine or betaine, trimethylamine-N-oxide (TMAO) is formed by gut microbiota and liver enzymes. Elevated TMAO plasma levels were associated with increased cardiovascular risk and other diseases. Also betaine and choline itself were recently associated with increased cardiovascular risk. A newly developed LC-HRMS method was applied to measure the plasma concentrations of TMAO, betaine and choline in a cohort of 339 patients undergoing coronary angiography for the evaluation of suspected coronary artery disease. Betaine concentrations in males were significantly higher than in females (42.0 vs. 35.9 μmol/L; p < 0.001). Plasma concentrations of TMAO but not of betaine or choline were higher in patients with diabetes compared to euglycemic patients (2.39 vs. 0.980 μmol/L; p = 0.001) as well as in patients with metabolic syndrome as compared to patients without metabolic syndrome (2.37 vs. 1.43 μmol/L; p = 0.002). Plasma concentrations of TMAO or choline increased significantly with decreasing renal function (Spearman's rho: -0.281; p < 0.001). However, plasma levels of TMAO or betaine were associated with neither a history of myocardial infarction nor the angiographically assessed presence of coronary heart disease, nor incident cardiovascular events during 8 years of follow-up. Plasma levels of choline were significantly lower in patients with a history of acute myocardial infarction as compared to those without such history (10.0 vs. 10.8 μmol/L; p = 0.045). Plasma levels of TMAO are confounded by impaired kidney function and poor metabolic control but are not associated with the history, presence or incidence of symptoms or events of coronary heart disease. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Coronary Artery-Bypass-Graft Surgery Increases the Plasma Concentration of Exosomes Carrying a Cargo of Cardiac MicroRNAs: An Example of Exosome Trafficking Out of the Human Heart with Potential for Cardiac Biomarker Discovery

PubMed Central

Emanueli, Costanza; Fiorentino, Francesca; Reeves, Barnaby C.; Beltrami, Cristina; Mumford, Andrew; Clayton, Aled; Gurney, Mark; Shantikumar, Saran; Angelini, Gianni D.

2016-01-01

Introduction Exosome nanoparticles carry a composite cargo, including microRNAs (miRs). Cultured cardiovascular cells release miR-containing exosomes. The exosomal trafficking of miRNAs from the heart is largely unexplored. Working on clinical samples from coronary-artery by-pass graft (CABG) surgery, we investigated if: 1) exosomes containing cardiac miRs and hence putatively released by cardiac cells increase in the circulation after surgery; 2) circulating exosomes and exosomal cardiac miRs correlate with cardiac troponin (cTn), the current “gold standard” surrogate biomarker of myocardial damage. Methods and Results The concentration of exosome-sized nanoparticles was determined in serial plasma samples. Cardiac-expressed (miR-1, miR-24, miR-133a/b, miR-208a/b, miR-210), non-cardiovascular (miR-122) and quality control miRs were measured in whole plasma and in plasma exosomes. Linear regression analyses were employed to establish the extent to which the circulating individual miRs, exosomes and exosomal cardiac miR correlated with cTn-I. Cardiac-expressed miRs and the nanoparticle number increased in the plasma on completion of surgery for up to 48 hours. The exosomal concentration of cardiac miRs also increased after CABG. Cardiac miRs in the whole plasma did not correlate significantly with cTn-I. By contrast cTn-I was positively correlated with the plasma exosome level and the exosomal cardiac miRs. Conclusions The plasma concentrations of exosomes and their cargo of cardiac miRs increased in patients undergoing CABG and were positively correlated with hs-cTnI. These data provide evidence that CABG induces the trafficking of exosomes from the heart to the peripheral circulation. Future studies are necessary to investigate the potential of circulating exosomes as clinical biomarkers in cardiac patients. PMID:27128471

Association between Plasma 25-Hydroxyvitamin D, Ancestry and Aggressive Prostate Cancer among African Americans and European Americans in PCaP

PubMed Central

Steck, Susan E.; Arab, Lenore; Zhang, Hongmei; Bensen, Jeannette T.; Fontham, Elizabeth T. H.; Johnson, Candace S.; Mohler, James L.; Smith, Gary J.; Su, Joseph L.; Trump, Donald L.; Woloszynska-Read, Anna

2015-01-01

Background African Americans (AAs) have lower circulating 25-hydroxyvitamin D3 [25(OH)D3] concentrations and higher prostate cancer (CaP) aggressiveness than other racial/ethnic groups. The purpose of the current study was to examine the relationship between plasma 25(OH)D3, African ancestry and CaP aggressiveness among AAs and European Americans (EAs). Methods Plasma 25(OH)D3 was measured using LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometry) in 537 AA and 663 EA newly-diagnosed CaP patients from the North Carolina-Louisiana Prostate Cancer Project (PCaP) classified as having either ‘high’ or ‘low’ aggressive disease based on clinical stage, Gleason grade and prostate specific antigen at diagnosis. Mean plasma 25(OH)D3 concentrations were compared by proportion of African ancestry. Logistic regression was used to calculate multivariable adjusted odds ratios (OR) and 95% confidence intervals (95%CI) for high aggressive CaP by tertile of plasma 25(OH)D3. Results AAs with highest percent African ancestry (>95%) had the lowest mean plasma 25(OH)D3 concentrations. Overall, plasma 25(OH)D3 was associated positively with aggressiveness among AA men, an association that was modified by calcium intake (ORT3vs.T1: 2.23, 95%CI: 1.26–3.95 among men with low calcium intake, and ORT3vs.T1: 0.19, 95%CI: 0.05–0.70 among men with high calcium intake). Among EAs, the point estimates of the ORs were <1.0 for the upper tertiles with CIs that included the null. Conclusions Among AAs, plasma 25(OH)D3 was associated positively with CaP aggressiveness among men with low calcium intake and inversely among men with high calcium intake. The clinical significance of circulating concentrations of 25(OH)D3 and interactions with calcium intake in the AA population warrants further study. PMID:25919866

Monitoring of argatroban and lepirudin anticoagulation in critically ill patients by conventional laboratory parameters and rotational thromboelastometry - a prospectively controlled randomized double-blind clinical trial.

PubMed

Beiderlinden, Martin; Werner, Patrick; Bahlmann, Astrid; Kemper, Johann; Brezina, Tobias; Schäfer, Maximilian; Görlinger, Klaus; Seidel, Holger; Kienbaum, Peter; Treschan, Tanja A

2018-02-09

Argatroban or lepirudin anticoagulation therapy in patients with heparin induced thrombocytopenia (HIT) or HIT suspect is typically monitored using the activated partial thromboplastin time (aPTT). Although aPTT correlates well with plasma levels of argatroban and lepirudin in healthy volunteers, it might not be the method of choice in critically ill patients. However, in-vivo data is lacking for this patient population. Therefore, we studied in vivo whether ROTEM or global clotting times would provide an alternative for monitoring the anticoagulant intensity effects in critically ill patients. This study was part of the double-blind randomized trial "Argatroban versus Lepirudin in critically ill patients (ALicia)", which compared critically ill patients treated with argatroban or lepirudin. Following institutional review board approval and written informed consent, for this sub-study blood of 35 critically ill patients was analysed. Before as well as 12, 24, 48 and 72 h after initiation of argatroban or lepirudin infusion, blood was analysed for aPTT, aPTT ratios, thrombin time (TT), INTEM CT,INTEM CT ratios, EXTEM CT, EXTEM CT ratios and maximum clot firmness (MCF) and correlated with the corresponding plasma concentrations of the direct thrombin inhibitor. To reach a target aPTT of 1.5 to 2 times baseline, median [IQR] plasma concentrations of 0.35 [0.01-1.2] μg/ml argatroban and 0.17 [0.1-0.32] μg/ml lepirudin were required. For both drugs, there was no significant correlation between aPTT and aPTT ratios and plasma concentrations. INTEM CT, INTEM CT ratios, EXTEM CT, EXTEM CT ratios, TT and TT ratios correlated significantly with plasma concentrations of both drugs. Additionally, agreement between argatroban plasma levels and EXTEM CT and EXTEM CT ratios were superior to agreement between argatroban plasma levels and aPTT in the Bland Altman analysis. MCF remained unchanged during therapy with both drugs. In critically ill patients, TT and ROTEM parameters may provide better correlation to argatroban and lepirudin plasma concentrations than aPTT. ClinicalTrials.gov , NCT00798525 , registered on 25 Nov 2008.

The Association of Dietary Intake of Purine-Rich Vegetables, Sugar-Sweetened Beverages and Dairy with Plasma Urate, in a Cross-Sectional Study

PubMed Central

Zgaga, Lina; Theodoratou, Evropi; Kyle, Janet; Farrington, Susan M.; Agakov, Felix; Tenesa, Albert; Walker, Marion; McNeill, Geraldine; Wright, Alan F.; Rudan, Igor; Dunlop, Malcolm G.; Campbell, Harry

2012-01-01

Introduction Hyperuricemia is a strong risk factor for gout. The incidence of gout and hyperuricemia has increased recently, which is thought to be, in part, due to changes in diet and lifestyle. Objective of this study was to investigate the association between plasma urate concentration and: a) food items: dairy, sugar-sweetened beverages (SSB) and purine-rich vegetables; b) related nutrients: lactose, calcium and fructose. Methods A total of 2,076 healthy participants (44% female) from a population-based case-control study in Scotland (1999–2006) were included in this study. Dietary data was collected using a semi-quantitative food frequency questionnaire (FFQ). Nutrient intake was calculated using FFQ and composition of foods information. Urate concentration was measured in plasma. Results Mean urate concentration was 283.8±72.1 mmol/dL (females: 260.1±68.9 mmol/dL and males: 302.3±69.2 mmol/dL). Using multivariate regression analysis we found that dairy, calcium and lactose intakes were inversely associated with urate (p = 0.008, p = 0.003, p = 0.0007, respectively). Overall SSB consumption was positively associated with urate (p = 0.008), however, energy-adjusted fructose intake was not associated with urate (p = 0.66). The intake of purine-rich vegetables was not associated to plasma urate (p = 0.38). Conclusions Our results suggest that limiting purine-rich vegetables intake for lowering plasma urate may be ineffectual, despite current recommendations. Although a positive association between plasma urate and SSB consumption was found, there was no association with fructose intake, suggesting that fructose is not the causal agent underlying the SSB-urate association. The abundant evidence supporting the inverse association between plasma urate concentration and dairy consumption should be reflected in dietary guidelines for hyperuricemic individuals and gout patients. Further research is needed to establish which nutrients and food products influence plasma urate concentration, to inform the development of evidence-based dietary guidelines. PMID:22701608

Quantification of seven β-lactam antibiotics and two β-lactamase inhibitors in human plasma using a validated UPLC-MS/MS method.

PubMed

Carlier, Mieke; Stove, Veronique; Roberts, Jason A; Van de Velde, Eric; De Waele, Jan J; Verstraete, Alain G

2012-11-01

There is an increasing interest in monitoring plasma concentrations of β-lactam antibiotics. The objective of this work was to develop and validate a rapid ultra-performance liquid chromatographic method with tandem mass spectrometric detection (UPLC-MS/MS) for simultaneous quantification of amoxicillin, ampicillin, cefuroxime, cefazolin, ceftazidime, meropenem, piperacillin, clavulanic acid and tazobactam. Sample clean-up included protein precipitation with acetonitrile and back-extraction of acetonitrile with dichloromethane. Six deuterated β-lactam antibiotics were used as internal standards. Chromatographic separation was performed on a Waters ACQUITY UPLC system using a BEH C(18) column (1.7 μm, 100 mm×2.1 mm) applying a binary gradient elution of water and acetonitrile both containing 0.1% formic acid. The total run time was 5.5 min. The developed method was validated in terms of precision, accuracy, linearity, matrix effect and recovery. The assay has now been successfully used to determine concentrations of amoxicillin/clavulanic acid, cefuroxime and meropenem in plasma samples from intensive care patients. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Determination of limonin in dog plasma by liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

PubMed

Liu, Shi-jia; Zhou, Ling; Zhang, Jun; Yu, Bo-yang; Li, Chang-yin; Liu, Zi-xiu; Ju, Wen-zheng

2013-04-01

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in beagle dog plasma using nimodipine as internal standard. The analyte and internal standard (IS) were extracted with ether followed by a rapid isocratic elution with 10 mm ammonium acetate buffer-methanol (26:74, v/v) on a C18 column (150 × 2.1 mm i.d.) and subsequent analysis by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/z 469.4 → 229.3 and m/z 417.2 → 122.0 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.625-100 ng/mL for limonin in dog plasma. The lower limit of quantification was 0.312 ng/mL and the extraction recovery was >90.4% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 9.9%. The method was successfully applied to pharmacokinetic study of limonin in dogs. Copyright © 2012 John Wiley & Sons, Ltd.

Human kinetics of orally and intravenously administered low-dose 1,2-(13)C-dichloroacetate.

PubMed

Jia, Minghong; Coats, Bonnie; Chadha, Monisha; Frentzen, Barbara; Perez-Rodriguez, Javier; Chadik, Paul A; Yost, Richard A; Henderson, George N; Stacpoole, Peter W

2006-12-01

Dichloroacetate (DCA) is a putative environmental hazard, owing to its ubiquitous presence in the biosphere and its association with animal and human toxicity. We sought to determine the kinetics of environmentally relevant concentrations of 1,2-(13)C-DCA administered to healthy adults. Subjects received an oral or intravenous dose of 2.5 microg/kg of 1,2-(13)C-DCA. Plasma and urine concentrations of 1,2-(13)C-DCA were measured by a modified gas chromatography-tandem mass spectrometry method. 1,2-(13)C-DCA kinetics was determined by modeling using WinNonlin 4.1 software. Plasma concentrations of 1,2-(13)C-DCA peaked 10 minutes and 30 minutes after intravenous or oral administration, respectively. Plasma kinetic parameters varied as a function of dose and duration. Very little unchanged 1,2-(13)C-DCA was excreted in urine. Trace amounts of DCA alter its own kinetics after short-term exposure. These findings have important implications for interpreting the impact of this xenobiotic on human health.

Quantitative analysis of titanium concentration using calibration-free laser-induced breakdown spectroscopy (LIBS)

NASA Astrophysics Data System (ADS)

Zaitun; Prasetyo, S.; Suliyanti, M. M.; Isnaeni; Herbani, Y.

2018-03-01

Laser-induced breakdown spectroscopy (LIBS) can be used for quantitative and qualitative analysis. Calibration-free LIBS (CF-LIBS) is a method to quantitatively analyze concentration of elements in a sample in local thermodynamic equilibrium conditions without using available matrix-matched calibration. In this study, we apply CF-LIBS for quantitative analysis of Ti in TiO2 sample. TiO2 powder sample was mixed with polyvinyl alcohol and formed into pellets. An Nd:YAG pulsed laser at a wavelength of 1064 nm was focused onto the sample to generate plasma. The spectrum of plasma was recorded using spectrophotometer then compared to NIST spectral line to determine energy levels and other parameters. The value of plasma temperature obtained using Boltzmann plot is 8127.29 K and electron density from calculation is 2.49×1016 cm-3. Finally, the concentration of Ti in TiO2 sample from this study is 97% that is in proximity with the sample certificate.

Correlations between Different Heavy Metals in Diverse Body Fluids: Studies of Human Semen Quality

PubMed Central

Mínguez-Alarcón, Lidia; Mendiola, Jaime; Roca, Manuela; López-Espín, José J.; Guillén, José J.; Moreno, José M.; Moreno-Grau, Stella; Martínez-García, María J.; Vergara-Juárez, Nuria; Elvira-Rendueles, Belén; García-Sánchez, Antonio; Ten, Jorge; Bernabeu, Rafael; Torres-Cantero, Alberto M.

2012-01-01

It has been hypothesized that exposure to heavy metals may impair male reproduction. To measure the effect produced by low doses of heavy metals on semen parameters, it is necessary to clarify in which body fluids those measurements must be performed. Sixty-one men attending infertility clinics participated in our study. Concentrations of lead, cadmium, and mercury were measured in whole blood, blood plasma, and seminal plasma using spectroanalytical and electrochemical methods. Semen analyses were performed according to World Health Organization criteria. For statistical analysis, Spearman's rank correlations, mean comparison tests, and discriminant analysis were calculated. Significant correlations between the measured concentrations of the three heavy metals in the same biological fluids were observed. However, no similar relationship was seen when comparing the concentrations in different body fluids of the same metal. According to our results and previous publications, seminal plasma might be the best body fluid for assessing impairment of human semen parameters. PMID:22312326

Associations of aldosterone and renin concentrations with inflammation-the Study of Health in Pomerania and the German Conn's Registry.

PubMed

Grotevendt, A; Wallaschofski, H; Reincke, M; Adolf, C; Quinkler, M; Nauck, M; Hoffmann, W; Rettig, R; Hannemann, A

2017-08-01

Chronic inflammation is an age-independent and body mass index-independent contributor to the development of multi-morbidity. Alterations of the renin-angiotensin-aldosterone system are observed within the context of proinflammatory states. We assessed circulating aldosterone, renin, and inflammatory biomarker concentrations in healthy, normotensive subjects and patients with primary aldosteronism. We included 1177 normotensive individuals from the population-based Study of Health in Pomerania (first follow-up, Study of Health in Pomerania-1) and 103 primary aldosteronism patients from the German Conn's Registry. A 1:1 matching for sex, age, body mass index, smoking status, diabetes mellitus, and the estimated glomerular filtration rate was performed to determine whether primary aldosteronism patients exhibit higher inflammatory biomarker concentrations than normotensive controls. The associations of plasma aldosterone concentration or plasma renin concentration with circulating fibrinogen concentrations, white blood cell count, and high sensitive C-reactive protein concentrations in the normotensive sample were determined with multivariable linear and logistic regression analyses. 1:1 matched primary aldosteronism patients demonstrated significantly (p < 0.01) higher plasma aldosterone concentration (198 vs. 47 ng/l), lower plasma renin concentration (3.1 vs. 7.7 ng/l) and higher high sensitive C-reactive protein concentrations (1.5 vs. 1.0 mg/l) than normotensive controls. Within the normotensive cohort, plasma renin concentration but not plasma aldosterone concentration was positively associated with fibrinogen concentrations and white blood cell count. Further, a J-shaped association between plasma renin concentration and high sensitive C-reactive protein concentrations was detected. High plasma aldosterone concentration in a primary aldosteronism cohort and high plasma renin concentration in normotensive subjects are associated with increased concentrations of inflammatory biomarkers. This suggests a link between the renin-angiotensin-aldosterone system and inflammatory processes in patients with primary aldosteronism and even in normotensive subjects.

Decreased Plasma Brain-Derived Neurotrophic Factor and Vascular Endothelial Growth Factor Concentrations during Military Training

PubMed Central

Nibuya, Masashi; Ishida, Toru; Yamamoto, Tetsuo; Mukai, Yasuo; Mitani, Keiji; Tsumatori, Gentaro; Scott, Daniel; Shimizu, Kunio

2014-01-01

Decreased concentrations of plasma brain-derived neurotrophic factor (BDNF) and serum BDNF have been proposed to be a state marker of depression and a biological indicator of loaded psychosocial stress. Stress evaluations of participants in military mission are critically important and appropriate objective biological parameters that evaluate stress are needed. In military circumstances, there are several problems to adopt plasma BDNF concentration as a stress biomarker. First, in addition to psychosocial stress, military missions inevitably involve physical exercise that increases plasma BDNF concentrations. Second, most participants in the mission do not have adequate quality or quantity of sleep, and sleep deprivation has also been reported to increase plasma BDNF concentration. We evaluated plasma BDNF concentrations in 52 participants on a 9-week military mission. The present study revealed that plasma BDNF concentration significantly decreased despite elevated serum enzymes that escaped from muscle and decreased quantity and quality of sleep, as detected by a wearable watch-type sensor. In addition, we observed a significant decrease in plasma vascular endothelial growth factor (VEGF) during the mission. VEGF is also neurotrophic and its expression in the brain has been reported to be up-regulated by antidepressive treatments and down-regulated by stress. This is the first report of decreased plasma VEGF concentrations by stress. We conclude that decreased plasma concentrations of neurotrophins can be candidates for mental stress indicators in actual stressful environments that include physical exercise and limited sleep. PMID:24586790

LC/MS Method for the Determination of Stable Isotope Labeled Promethazine in Human Plasma

NASA Technical Reports Server (NTRS)

Zuwei, Wang; Boyd, Jason; Berens, Kurt L.; Putcha, Lakshmi

2004-01-01

Promethazine (PMZ) is taken by astronauts orally (PO), intramuscularly (IM) or rectally (PR) for space motion sickness. LC/MS method was developed with off-line solid phase extraction to measure plasma concentrations of PMZ given as stable isotope-labeled (SIL) formulations by the three different routes of administration simultaneously. Samples (0.5ml) were loaded on to Waters Oasis HLB co-polymer cartridges and eluted with 1.0 mL methanol. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 6 min. Acetonitrile/ ammonium acetate (30 mM) in water (3:2, v/v), pH 5.6 plus or minus 0.1, was used as the mobile phase for separation. Concentrations of PMZ, PMZ-d4 and PMZ-d7 and chlorpromazine (internal standard) were determined using a Micromass ZMD single quadrupole mass spectrometer with Electrospray Ionization (ESI). ESI mass spectra were acquired in positive ion mode with selected ion monitoring of [M+ H]dot plus. The method is rapid, reproducible and the assay specific parameters are listed in a table. A novel, sensitive and specific method for the measurement of PMZ and SIL PMZ in human plasma is reported.

Quantification of lipoic acid in plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Chen, Jun; Jiang, Wenming; Cai, Jia; Tao, Weixing; Gao, Xiaoling; Jiang, Xinguo

2005-09-25

A sensitive and specific liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of lipoic acid (LA) in human plasma. LA and the internal standard, naproxen, were extracted from a 500 microl plasma sample by one-step deproteination using acetonitrile. Chromatographic separation was performed on a Zorbax SB-C(18) Column (100 mmx3.0mm i.d. with 3.5 microm particle size) with the mobile phase consisting of acetonitrile and 0.1% acetic acid (pH 4, adjusted with ammonia solution) (65:35, v/v), and the flow rate was set at 0.3 ml/min. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method was linear over the concentration range of 5-10,000 ng/ml for LA. The intra- and inter-day precisions were less than 7% and accuracy ranged from -7.87 to 9.74% at the LA concentrations tested. The present method provides a relatively simple and sensitive assay with short turn-around time. The method has been successfully applied to a clinical pharmacokinetic study of LA in 10 healthy subjects.

Pharmacokinetic study of mangiferin in rat plasma and retina using high-performance liquid chromatography

PubMed Central

Hou, Yunlong; Fan, Shengjun; Gu, Yuanqin; Yu, Xuhui; Li, Baoxin

2010-01-01

Purpose Although the naturally occurring antioxidant mangiferin has been widely used, it is not yet known whether it can cross the blood-retina barrier (BRB) and enter the eye. The purpose of this experiment was to investigate the ability of mangiferin to pass the blood-retina barrier. Methods Sprague–Dawley rats were used for biologic fluid sampling after intravenous administration of mangiferin at doses of 10, 25, and 50 mg/kg. Blood and retina samples were collected at different time points post-dose. High-performance liquid chromatography (HPLC) separation was conducted on a COSMOSIL 5C18—MS—II column (4.6 mm×250 mm, 5 μm) with a flow rate of 1.0 ml/min using a mobile phase comprised of methanol −2% glacial acetic acid (40:60 v:v). Results The HPLC method has proven suitable to determine the presence of mangiferin in the eye. The plasma concentration of mangiferin was dose dependent. Pharmacokinetic parameters of mangiferin in plasma after intravenous administration were fitted to the two-compartment model with the first-order elimination and first-order transfer between central and peripheral compartments. The concentration of mangiferin in the retina goes with that in the blood. Mangiferin concentrations in the retina reached 5.69±1.48 μg/ml 0.5 h after intravenous administration (50 mg/kg) and then dropped gradually to 0.30±0.02 μg/ml 5.0 h later. The eye–to-plasma concentration ratio was 2.80%. Conclusions Mangiferin can pass the blood-retina barrier after a single intravenous administration and may be a potential natural antioxidant in treating eye diseases. PMID:20806037

One mouse, one pharmacokinetic profile: quantitative whole blood serial sampling for biotherapeutics.

PubMed

Joyce, Alison P; Wang, Mengmeng; Lawrence-Henderson, Rosemary; Filliettaz, Cynthia; Leung, Sheldon S; Xu, Xin; O'Hara, Denise M

2014-07-01

The purpose of this study was to validate the approach of serial sampling from one mouse through ligand binding assay (LBA) quantification of dosed biotherapeutic in diluted whole blood to derive a pharmacokinetic (PK) profile. This investigation compared PK parameters obtained using serial and composite sampling methods following administration of human IgG monoclonal antibody. The serial sampling technique was established by collecting 10 μL of blood via tail vein at each time point following drug administration. Blood was immediately diluted into buffer followed by analyte quantitation using Gyrolab to derive plasma concentrations. Additional studies were conducted to understand matrix and sampling site effects on drug concentrations. The drug concentration profiles, irrespective of biological matrix, and PK parameters using both sampling methods were not significantly different. There were no sampling site effects on drug concentration measurements except that concentrations were slightly lower in sodium citrated plasma than other matrices. We recommend the application of mouse serial sampling, particularly with limiting drug supply or specialized animal models. Overall the efficiencies gained by serial sampling were 40-80% savings in study cost, animal usage, study length and drug conservation while inter-subject variability across PK parameters was less than 30%.

Acceleration and Transport of Particles in Collisionless Plasmas: Wakes due to the Interaction with Moving Bodies

NASA Astrophysics Data System (ADS)

Ponomarjov, Maxim G.

2001-06-01

A method is developed that allows the numerical and analytical description of the effects of ambient magnetic field on the time-dependent 3D structures of space plasma flows due to bodies in motion through a plasma. Some of these effects have been observed in space and ionosphere as stratified, flute and yacht sail like structures of plasma disturbances, jets, wakes and clouds. The method can be used for the simulations of Solar Wind flow taking into account the magnetic field effects and the interactions with the Interstellar Medium. These problems are of practical interest in fluid mechanics, space sciences, astrophysics, in turbulence theory. They also have some fundamental interest in their own right, as they enable one to concentrate on the effects of the ambient electric and magnetic fields.

Use of basal and TRH-stimulated plasma growth hormone concentrations to differentiate between primary hypothyroidism and nonthyroidal illness in dogs.

PubMed

Pijnacker, Tera; Kooistra, Hans S; Vermeulen, Cathelijne F; van der Vinne, Merel; Prins, Marrit; Galac, Sara; Mol, Jan A

2018-05-07

A low plasma total thyroxine (TT 4 ) concentration in combination with a plasma TSH concentration within reference range does not distinguish between hypothyroidism and nonthyroidal illness (NTI) in dogs. Hypothyroidism is associated with TSH-releasing hormone (TRH)-induced increased release of growth hormone (GH). Basal and TRH-induced plasma GH concentrations can be used to distinguish hypothyroid dogs from NTI dogs. Twenty-one dogs with signs consistent with hypothyroidism, a low plasma TT 4 concentration, and a plasma TSH concentration within reference interval. Case control study. Thyroid scintigraphy was performed to classify dogs as having hypothyroidism or NTI. All dogs underwent a TRH stimulation test with measurement of plasma concentrations of GH and TSH before and 30 and 45 minutes after IV administration of TRH. Eleven of the dogs were classified as hypothyroid and 10 as having NTI. Basal plasma GH concentration in the hypothyroid dogs (3.2 μg/l; range, 2.0 to 12.5 μg/l) was significantly higher (p<0.001) than that in the NTI dogs (.73 μg/l; range, .45 to 2.3 μg/l), with minimal overlap, and increased (p=.009) after TRH administration in hypothyroid dogs, whereas it did not change in NTI dogs. At T=45, plasma GH concentrations in hypothyroid dogs and NTI dogs did not overlap. The plasma TSH concentration did not change significantly after TRH administration in hypothyroid dogs, whereas it increased (p<.001) in NTI dogs. At T=45, there was no overlap in percentage TSH increase from baseline between hypothyroid dogs. Measurement of basal plasma GH concentration and concentrations of GH and TSH after TRH stimulation can distinguish between hypothyroidism and NTI in dogs. Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Clinical decision support of therapeutic drug monitoring of phenytoin: measured versus adjusted phenytoin plasma concentrations

PubMed Central

2012-01-01

Background Therapeutic drug monitoring of phenytoin by measurement of plasma concentrations is often employed to optimize clinical efficacy while avoiding adverse effects. This is most commonly accomplished by measurement of total phenytoin plasma concentrations. However, total phenytoin levels can be misleading in patients with factors such as low plasma albumin that alter the free (unbound) concentrations of phenytoin. Direct measurement of free phenytoin concentrations in plasma is more costly and time-consuming than determination of total phenytoin concentrations. An alternative to direct measurement of free phenytoin concentrations is use of the Sheiner-Tozer equation to calculate an adjusted phenytoin that corrects for the plasma albumin concentration. Innovative medical informatics tools to identify patients who would benefit from adjusted phenytoin calculations or from laboratory measurement of free phenytoin are needed to improve safety and efficacy of phenytoin pharmacotherapy. The electronic medical record for an academic medical center was searched for the time period from August 1, 1996 to November 30, 2010 for patients who had total phenytoin and free phenytoin determined on the same blood draw, and also a plasma albumin measurement within 7 days of the phenytoin measurements. The measured free phenytoin plasma concentration was used as the gold standard. Results In this study, the standard Sheiner-Tozer formula for calculating an estimated (adjusted) phenytoin level more frequently underestimates than overestimates the measured free phenytoin relative to the respective therapeutic ranges. Adjusted phenytoin concentrations provided superior classification of patients than total phenytoin measurements, particularly at low albumin concentrations. Albumin plasma concentrations up to 7 days prior to total phenytoin measurements can be used for adjusted phenytoin concentrations. Conclusions The results suggest that a measured free phenytoin should be obtained where possible to guide phenytoin dosing. If this is not feasible, then an adjusted phenytoin can supplement a total phenytoin concentration, particularly for patients with low plasma albumin. PMID:22333264

An LC-MS/MS method for simultaneous determination of nine steroidal saponins from Paris polyphylla var. in rat plasma and its application to pharmacokinetic study.

PubMed

Yang, Guangyi; Lu, Wei; Pan, Meng; Zhang, Chenning; Zhou, Yuan; Hu, Pei; Hu, Ming; Song, Gao

2017-10-25

Paris polyphylla var is an herbal plant herb widely used in Traditional Chinese Medicine. The purpose of this study is to develop an Ultra Performance Liquid Chromatography-tandem mass spectrometer (UPLC-MS) method to quantify the major components (i.e., nine saponins) from P. polyphylla in plasma samples. A UItra BiPh column (100×2.1mm, 5μm) was used with acetonitrile/0.1% formic acid in water as mobile phases. The analytes were quantified using a Waters XEVO TQ mass spectrometer via multiple reaction monitoring (MRM) with positive scan mode. A protein precipitation method was used to extract the analytes from rat plasma. The inter/intra-day precision, accuracy, recovery, matrix effect, and stability were evaluated per the FDA guidance. The method showed linearity in the concentration ranges of 2.4-1250ng/mL. The intra-day and inter-day precisions (RSD) of these analytes at three different levels were less than 15.0%. The extraction recoveries of these analytes were from 83.8% to 109.4% and the matrix effects ranged from 87.4% to 105.4%. The stabilities of these compounds in plasma were evaluated by analyzing three different concentrations following storage at 25°C for 6h, and -80°C for 30days. All the samples displayed less than 15.0% variations. The validated method was successfully used to a pharmacokinetic (PK) study using Sprague Dawley (SD) rats with intravenous (i.v.) and oral (p.o.) administration of P. polyphylla extract. The applications revealed that this method can be used to analyze major steroidal saponins from P. polyphylla in biological samples. Copyright © 2017 Elsevier B.V. All rights reserved.

A fully validated method for the determination of lacosamide in human plasma using gas chromatography with mass spectrometry: application for therapeutic drug monitoring.

PubMed

Nikolaou, Panagiota; Papoutsis, Ioannis; Spiliopoulou, Chara; Voudris, Constantinos; Athanaselis, Sotiris

2015-01-01

A simple gas chromatographic method with mass spectrometry detection was developed and validated for the determination of lacosamide in human plasma. Lacosamide and the internal standard, levetiracetam-d6, were extracted from 200 μL plasma, by a solid-phase extraction through HF Bond Elut C18 columns, and derivatized using N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide with 1% tert-butyldimethylsilylchloride in acetonitrile. The limit of quantification was found to be 0.20 μg/mL and the assay was linear up to 20.0 μg/mL with correlation coefficient ≥0.994. The intra- and interday precision values were <4.1% in terms of relative standard deviation (%) and the values of intra- and interday accuracy were found to be within -7.2 and 5.3% in terms of relative error (%). Absolute recovery of the method for lacosamide was determined at three concentration levels and ranged from 92.5 to 97.6%. The developed method uses small volumes of plasma and proved to be simple, rapid, and sensitive for the determination of lacosamide in plasma. This method can be used in routine every day analysis of plasma samples obtained from patients who follow respective antiepileptic treatment and for the investigation of clinical and forensic cases where lacosamide is involved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Consumption of canned citrus fruit meals increases human plasma β-cryptoxanthin concentration, whereas lycopene and β-carotene concentrations did not change in healthy adults.

PubMed

Zhu, Chenghao H; Gertz, Erik R; Cai, Yimeng; Burri, Betty J

2016-07-01

Several studies suggest that β-cryptoxanthin has a greater plasma response from its common food sources than other carotenoids such as β-carotene and lycopene. The hypothesis of this study is that changes in plasma β-cryptoxanthin concentrations will be greater than changes in plasma β-carotene or lycopene concentrations even if these carotenoids are fed in a similar food matrix, such as citrus fruit. We tested this hypothesis by measuring changes in plasma concentrations of β-cryptoxanthin, lycopene, and β-carotene after feeding measured amounts of canned tangerines and pink grapefruit to healthy nonsmoking adult humans. Volunteers served as their own controls and received both citrus fruit treatments randomly. In the first study, 8 subjects ate single meals of 234-304g of tangerines or 60-540g of pink grapefruit. The second study compared changes in plasma carotenoid concentration caused by feeding 234g of tangerines or 540g of pink grapefruit to 11 subjects. Blood was collected 5 times within 24hours after each citrus meal. Carotenoid concentrations were analyzed by reversed-phase high-performance liquid chromatography. Plasma β-cryptoxanthin concentrations increased within 5hours and then stabilized, remaining high throughout the 24hours measured. Plasma concentrations of lycopene and β-carotene did not change. These results show that β-cryptoxanthin concentrations increased after a citrus fruit meal, but lycopene and β-carotene concentrations did not change after a similar citrus fruit meal. These results support our hypothesis that changes in plasma β-cryptoxanthin are greater than changes in plasma lycopene or β-carotene, even when these carotenoids are fed in a similar food matrix. Published by Elsevier Inc.

Quantification of Transthyretin Kinetic Stability in Human Plasma Using Subunit Exchange

PubMed Central

2015-01-01

The transthyretin (TTR) amyloidoses are a group of degenerative diseases caused by TTR aggregation, requiring rate-limiting tetramer dissociation. Kinetic stabilization of TTR, by preferential binding of a drug to the native tetramer over the dissociative transition state, dramatically slows the progression of familial amyloid polyneuropathy. An established method for quantifying the kinetic stability of recombinant TTR tetramers in buffer is subunit exchange, in which tagged TTR homotetramers are added to untagged homotetramers at equal concentrations to measure the rate at which the subunits exchange. Herein, we report a subunit exchange method for quantifying the kinetic stability of endogenous TTR in human plasma. The subunit exchange reaction is initiated by the addition of a substoichiometric quantity of FLAG-tagged TTR homotetramers to endogenous TTR in plasma. Aliquots of the subunit exchange reaction, taken as a function of time, are then added to an excess of a fluorogenic small molecule, which immediately arrests further subunit exchange. After binding, the small molecule reacts with the TTR tetramers, rendering them fluorescent and detectable in human plasma after subsequent ion exchange chromatography. The ability to report on the extent of TTR kinetic stabilization resulting from treatment with oral tafamidis is important, especially for selection of the appropriate dose for patients carrying rare mutations. This method could also serve as a surrogate biomarker for the prediction of the clinical outcome. Subunit exchange was used to quantify the stabilization of WT TTR from senile systemic amyloidosis patients currently being treated with tafamidis (20 mg orally, once daily). TTR kinetic stability correlated with the tafamidis plasma concentration. PMID:24661308

Circulating Tumor DNA Measurement by Picoliter Droplet-Based Digital PCR and Vemurafenib Plasma Concentrations in Patients with Advanced BRAF-Mutated Melanoma.

PubMed

Garlan, Fanny; Blanchet, Benoit; Kramkimel, Nora; Puszkiel, Alicja; Golmard, Jean-Louis; Noe, Gaelle; Dupin, Nicolas; Laurent-Puig, Pierre; Vidal, Michel; Taly, Valerie; Thomas-Schoemann, Audrey

2017-06-01

Circulating tumor DNA (ctDNA) has been reported as a prognostic marker in melanoma. In BRAF V600-mutant melanoma, a plasma under-exposure to vemurafenib could favor emerging resistance but no biological data are available to support this hypothesis. We aimed to investigate the relationship between vemurafenib plasma concentrations and the ctDNA plasma concentration during follow-up of BRAF-mutated melanoma patients. Eleven patients treated with single-agent vemurafenib for advanced BRAF V600-mutant melanoma were analyzed in an exploratory monocentric study. The vemurafenib plasma concentration was measured by liquid chromatography. ctDNA was extracted from plasma samples and the ctDNA concentration was evaluated using picoliter droplet-based digital PCR with Taqman ® detection probes targeting the BRAF p.V600E/K mutation and wild-type BRAF sequences. At baseline, plasma ctDNA was detectable in 72% (n = 8/11) of patients and the ctDNA concentration decreased in 88% of these patients (n = 7/8) from day (D) 0 to D15 after vemurafenib initiation. During follow-up, an increased ctDNA concentration was detected in nine patients: in five patients, the first increase in ctDNA concentrations followed a decrease in vemurafenib concentrations. More interestingly, an inverse correlation between vemurafenib concentration and ctDNA concentrations was demonstrated (p = 0.026). The ctDNA concentration at baseline was associated with overall survival (hazard ratio = 2.61, 95% CI 1.04-6.56; p = 0.04). This study demonstrates the relevance of vemurafenib plasma monitoring during the follow-up of metastatic melanoma patients. Plasma drug monitoring and ctDNA concentrations could be combined to monitor tumor evolution in melanoma patients treated with anti-BRAF therapies.

LC/MS/MS quantitation assay for pharmacokinetics of naringenin and double peaks phenomenon in rats plasma.

PubMed

Ma, Yan; Li, Peibo; Chen, Dawei; Fang, Tiezheng; Li, Haitian; Su, Weiwei

2006-01-13

A highly sensitive and specific electrospray ionization (ESI) liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for quantitation of naringenin (NAR) and an explanation for the double peaks phenomenon was developed and validated. NAR was extracted from rat plasma and tissues along with the internal standard (IS), hesperidin, with ethyl acetate. The analytes were analyzed in the multiple-reaction-monitoring (MRM) mode as the precursor/product ion pair of m/z 273.4/151.3 for NAR and m/z 611.5/303.3 for the IS. The assay was linear over the concentration range of 5-2500 ng/mL. The lower limit quantification was 5 ng/mL, available for plasma pharmacokinetics of NAR in rats. Accuracy in within- and between-run precisions showed good reproducibility. When NAR was administered orally, only little and predominantly its glucuronidation were into circulation in the plasma. There existed double peaks phenomenon in plasma concentration-time curve leading to the relatively slow elimination of NAR in plasma. The results showed that there was a linear relationship between the AUC of total NAR and dosages. And the double peaks are mainly due to enterohepatic circulation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballermann, B.J.

To enable serial measurements of plasma atrial natriuretic peptide (ANP) concentrations in the rat, a microradioreceptor assay (RRA) for this hormone was developed. Glomerular microsomes bearing ANP receptors were used to bind ANP. The smallest quantity of ANP detectable by this method was 0.2 fmol/sample. By contrast, a radioimmunoassay for ANP was sensitive to 2.4 fmol/sample. The intra- and interassay coefficients of variation for the RRA were 4.1 and 11.6%, respectively. Recovery of 10, 20, 50, and 100 pM synthetic ANP added to unextracted rat plasma was essentially 100%. Biologically inactive, synthetic amino- and carboxy-terminal ANP fragments added to ratmore » plasma were not detected. Plasma ANP was stable when measured four consecutive times at 90-min intervals in 10 fasting rats. In a separate group of rats, fasting plasma ANP levels averaged 34 {plus minus} 3 and rose to 57 {plus minus} 5 pM in the postprandial state, whereas levels in fasting time controls remained constant. It is concluded that the RRA for ANP described here detects ANP in microliter quantities of unextracted rat plasma. Thus serial measurements of ANP concentrations can be undertaken in rats without inducing major changes in the volume status.« less

Effect of racemic ibuprofen dose on the magnitude and duration of platelet cyclo-oxygenase inhibition: relationship between inhibition of thromboxane production and the plasma unbound concentration of S(+)-ibuprofen.

PubMed

Evans, A M; Nation, R L; Sansom, L N; Bochner, F; Somogyi, A A

1991-02-01

1. Four healthy male subjects received racemic ibuprofen (200, 400, 800 and 1200 mg), orally, on four occasions, 2 weeks apart, according to a four-way Latin-square design, in order to investigate the influence of increasing dose of ibuprofen on the magnitude and duration of its antiplatelet effect as well as on the relationship between such effect and drug concentration. 2. The antiplatelet effect of ibuprofen was assessed by measuring the inhibition of platelet thromboxane B2 (TXB2) generation during the controlled clotting of whole blood. The plasma unbound concentration of S(+)-ibuprofen, the enantiomer shown in an in vitro study to be responsible for the inhibitory effect of platelet TXB2 generation, was measured using an enantioselective method. 3. The maximum percentage inhibition of TXB2 generation increased significantly with dose from a mean +/- s.d. of 93.4 +/- 1.2% after the 200 mg dose to 98.8 +/- 0.3% after the 1200 mg dose, and there was an increase with dose in the duration of inhibition of TXB2 generation. The effect of ibuprofen on platelet TXB2 generation was transient and mirrored the time-course of unbound S(+)-ibuprofen in plasma; on all but one of the 16 occasions, serum TXB2 concentrations returned to at least within 10% of the pretreatment concentrations within 24 h of ibuprofen administration. 4. For each subject, the relationship between the percentage inhibition of TXB2 generation and the unbound concentration of S(+)-ibuprofen in plasma was modelled according to a sigmoidal Emax equation. The mean plasma unbound concentration of S(+)-ibuprofen required to inhibit platelet TXB2 generation by 50% (EC50) was 9.8 +/- 1.0 micrograms l-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity of Tumor Necrosis Factor-alpha (TNF-alpha) and its soluble type I receptor (p55TNF-R) in some drug-induced cutaneous reactions.

PubMed

Chodorowska, Grazyna; Czelej, Dorota; Niewiedzioł, Marta

2003-01-01

Plasma concentration of TNF-alpha and its type I receptor (p55TNF-R) was examined in 126 patients with drug-induced skin reactions using immunoenzymatic ELISA method. Patients were subdivided into 6 groups: maculopapular eruptions (ME), erythema multiforme (EM), erythema multiforme coexisting with erythema nodosum (EMN), hyperergic vasculitis (HV), Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN). In the acute clinical stage highly significant (p<0.001) or significant (p<0.01) elevation of mean plasma concentrations of the cytokine and its receptor was found in all examined groups in comparison with the control. Clearing of clinical symptoms was connected with considerable decrease (p<0.001, p<0.01) of mean plasma levels of the both proteins in comparison with the before treatment values. TNF-alpha concentrations still remained significantly more elevated than those observed in the control. The results indicate that plasma activity of TNF-alpha and its p55 receptor change with the clinical course of the examined drug-induced skin reactions, which suggests the partake of both proteins in the pathogenesis of these diseases.

Differentiation of colloidal and dissolved silica: Analytical separation using spectrophotometry and inductively coupled plasma atomic emission spectrometry

USGS Publications Warehouse

Lewis-Russ, A.; Ranville, J.; Kashuba, A.T.

1991-01-01

A method is described that differentiates between solutions containing silica-dominated colloids and solutions that are essentially free of colloids. Suspensions of tuff particles were treated to remove colloids by centrifugation, filtration or both. Agreement of silica concentrations determined by inductively coupled plasma atomic emission spectrometry and by a spectrophotometric method was taken as an indication of colloid-free solutions. For two tuffs, centrifugation was effective for removing colloids. For the third, highly altered tuff, filtration was more effective for removing colloids.

Zinc Supplementation Alters Plasma Aluminum and Selenium Status of Patients Undergoing Dialysis: A Pilot Study

PubMed Central

Guo, Chih-Hung; Chen, Pei-Chung; Hsu, Guoo-Shyng W.; Wang, Chia-Liang

2013-01-01

End stage renal disease patients undergoing long-term dialysis are at risk for abnormal concentrations of certain essential and non-essential trace metals and high oxidative stress. We evaluated the effects of zinc (Zn) supplementation on plasma aluminum (Al) and selenium (Se) concentrations and oxidative stress in chronic dialysis patients. Zn-deficient patients receiving continuous ambulatory peritoneal dialysis or hemodialysis were divided into two groups according to plasma Al concentrations (HA group, Al > 50 μg/L; and MA group, Al > 30 to ≤ 50 μg/L). All patients received daily oral Zn supplements for two months. Age- and gender-matched healthy individuals did not receive Zn supplement. Clinical variables were assessed before, at one month, and after the supplementation period. Compared with healthy subjects, patients had significantly lower baseline plasma Se concentrations and higher oxidative stress status. After two-month Zn treatment, these patients had higher plasma Zn and Se concentrations, reduced plasma Al concentrations and oxidative stress. Furthermore, increased plasma Zn concentrations were related to the concentrations of Al, Se, oxidative product malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase activities. In conclusion, Zn supplementation ameliorates abnormally high plasma Al concentrations and oxidative stress and improves Se status in long-term dialysis patients. PMID:23609777

Short-Term Vitamin B-6 Restriction Does Not Affect Plasma Concentrations of Hydrogen Sulfide Biomarkers Lanthionine and Homolanthionine in Healthy Men and Women123

PubMed Central

DeRatt, Barbara N; Ralat, Maria A; Gregory, Jesse F

2016-01-01

Background: Suboptimal vitamin B-6 status is associated with increased cardiovascular disease risk, although the mechanism is unknown. The synthesis of the vasodilator hydrogen sulfide occurs through side reactions of the transsulfuration enzymes cystathionine β-synthase and cystathionine γ-lyase, with pyridoxal 5′-phosphate as a coenzyme. Two proposed hydrogen sulfide biomarkers, lanthionine and homolanthionine, are produced concurrently. Objective: To determine whether hydrogen sulfide production is reduced by vitamin B-6 deficiency, we examined the relations between plasma concentrations of lanthionine and homolanthionine, along with other components of the transsulfuration pathway (homocysteine, cystathionine, and Cys), in a secondary analysis of samples from 2 vitamin B-6 restriction studies in healthy men and women. Methods: Metabolite concentrations were measured in plasma from 23 healthy adults (12 men and 11 women) before and after 28-d controlled dietary vitamin B-6 restriction (0.37 ± 0.04 mg/d). Vitamin B-6 restriction effects on lanthionine and homolanthionine concentrations were assessed. Associations between hydrogen sulfide biomarkers, transsulfuration metabolites, and functional indicators of vitamin B-6 deficiency were analyzed by linear regression. Results: Preprandial plasma lanthionine and homolanthionine concentrations ranged from 89.0 to 372 nmol/L and 5.75 to 32.3 nmol/L, respectively, in healthy adults. Mean lanthionine and homolanthionine concentrations were not affected by vitamin B-6 restriction (P < 0.66), with marked heterogeneity of individual responses. After restriction, homolanthionine was positively associated with functional indicators of vitamin B-6 deficiency, which differed from hypothesized negative associations. Plasma lanthionine was positively correlated with the concentration of its precursor, Cys, before (R2 = 0.36; P = 0.002) and after (R2 = 0.37; P = 0.002) restriction. Likewise, homolanthionine concentration was positively correlated with its precursor homocysteine, but only in vitamin B-6 adequacy (R2 = 0.41; P < 0.001). Conclusions: The resiliency of plasma lanthionine and homolanthionine concentrations after short-term vitamin B-6 restriction suggests a minimal effect of moderate vitamin B-6 deficiency on hydrogen sulfide production. Additional research is needed to better understand the metabolism and disposal of these biomarkers in humans. This study was registered at clinicaltrials.gov as NCT00877812. PMID:26962179

Simultaneous analysis of retinol, all-trans- and 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid in plasma by liquid chromatography using on-column concentration after single-phase fluid extraction.

PubMed

Teerlink, T; Copper, M P; Klaassen, I; Braakhuis, B J

1997-06-20

A reversed-phase high-performance liquid chromatographic method for the simultaneous analysis of retinol, all-trans-retinoic acid, 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid in human plasma and cell culture medium is described. Sample preparation involves precipitation of proteins and extraction of retinoids with 60% acetonitrile. After centrifugation, the acetonitrile content of the supernatant is reduced to 45%, allowing on-column concentration of analytes. Injection volumes up to 2.0 ml (equivalent to 0.525 ml of sample) can be used without compromising chromatographic resolution of all-trans-retinoic acid and 13-cis-retinoic acid. Retinoids were stable in this extract and showed no isomerization when stored in the dark in a cooled autosampler, allowing automated analysis of large series of samples. Recoveries from spiked plasma samples were between 95 and 103%. Although no internal standard was used, the inter-assay precision for all retinoids was better than 6% and 4% at concentrations of 30 nM and 100 nM, respectively. The method is a valuable tool for the study of cellular metabolism of all-trans-retinoic acid, as polar metabolites of this compound can be detected with high sensitivity in cell culture media.

Estimation of the quantification uncertainty from flow injection and liquid chromatography transient signals in inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Laborda, Francisco; Medrano, Jesús; Castillo, Juan R.

2004-06-01

The quality of the quantitative results obtained from transient signals in high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) and flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS) was investigated under multielement conditions. Quantification methods were based on multiple-point calibration by simple and weighted linear regression, and double-point calibration (measurement of the baseline and one standard). An uncertainty model, which includes the main sources of uncertainty from FI-ICPMS and HPLC-ICPMS (signal measurement, sample flow rate and injection volume), was developed to estimate peak area uncertainties and statistical weights used in weighted linear regression. The behaviour of the ICPMS instrument was characterized in order to be considered in the model, concluding that the instrument works as a concentration detector when it is used to monitorize transient signals from flow injection or chromatographic separations. Proper quantification by the three calibration methods was achieved when compared to reference materials, although the double-point calibration allowed to obtain results of the same quality as the multiple-point calibration, shortening the calibration time. Relative expanded uncertainties ranged from 10-20% for concentrations around the LOQ to 5% for concentrations higher than 100 times the LOQ.

Pharmacokinetic Study of Di-Phenyl-Di-(2,4-Difluobenzohydroxamato)Tin(IV): Novel Metal-Based Complex with Promising Antitumor Potential

PubMed Central

Li, Yunlan; Gao, Zhuyan; Guo, Pu; Li, Qingshan

2012-01-01

Di-phenyl-di-(2,4-difluobenzohydroxamato)tin(IV)(DPDFT), a new metal-based arylhydroxamate antitumor complex, showed high in vivo and in vitro antitumor activity with relative low toxicity, but no data was reported regarding its pharmacokinetics and dependent toxicity. In this paper, a rapid, sensitive, and reproducible HPLC method in vivo using Diamonsil ODS column with a mixture of methanol and phosphoric acid in water (30 : 70, V/V, pH 3.0) as mobile phase was developed and validated for the determination of DPDFT. The plasma was deproteinized with methanol that contained acetanilide as the internal standard (I.S.). The photodiode array detector was set at a wavelength of 228 nm at room temperature and a linear curve over the concentration range 0.1~25 μg·mL−1 (r = 0.9993) was obtained. The method was used to determine the concentration-time profiles for DPDFT in the plasma after single intravenous administration with doses of 5, 10, 15 mg·kg−1 to rats. The pharmacokinetics parameter calculations and modeling were carried out using the 3p97 software. The results showed that the concentration-time curves of DPDFT in rat plasma could be fitted to two-compartment model. PMID:22400014

Dietary omega-6 fatty acid lowering increases bioavailability of omega-3 polyunsaturated fatty acids in human plasma lipid pools.

PubMed

Taha, Ameer Y; Cheon, Yewon; Faurot, Keturah F; Macintosh, Beth; Majchrzak-Hong, Sharon F; Mann, J Douglas; Hibbeln, Joseph R; Ringel, Amit; Ramsden, Christopher E

2014-05-01

Dietary linoleic acid (LA, 18:2n-6) lowering in rats reduces n-6 polyunsaturated fatty acid (PUFA) plasma concentrations and increases n-3 PUFA (eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) concentrations. To evaluate the extent to which 12 weeks of dietary n-6 PUFA lowering, with or without increased dietary n-3 PUFAs, alters unesterified and esterified plasma n-6 and n-3 PUFA concentrations in subjects with chronic headache. Secondary analysis of a randomized trial. Subjects with chronic headache were randomized for 12 weeks to (1) average n-3, low n-6 (L6) diet; or (2) high n-3, low n-6 LA (H3-L6) diet. Esterified and unesterified plasma fatty acids were quantified at baseline (0 weeks) and after 12 weeks on a diet. Compared to baseline, the L6 diet reduced esterified plasma LA and increased esterified n-3 PUFA concentrations (nmol/ml), but did not significantly change plasma arachidonic acid (AA, 20:4n-6) concentration. In addition, unesterified EPA concentration was increased significantly among unesterified fatty acids. The H3-L6 diet decreased esterified LA and AA concentrations, and produced more marked increases in esterified and unesterified n-3 PUFA concentrations. Dietary n-6 PUFA lowering for 12 weeks significantly reduces LA and increases n-3 PUFA concentrations in plasma, without altering plasma AA concentration. A concurrent increase in dietary n-3 PUFAs for 12 weeks further increases n-3 PUFA plasma concentrations and reduces AA. Published by Elsevier Ltd.

Dietary omega-6 fatty acid lowering increases bioavailability of omega-3 polyunsaturated fatty acids in human plasma lipid pools

PubMed Central

Taha, Ameer Y.; Cheon, Yewon; Faurot, Keturah F.; MacIntosh, Beth; Majchrzak-Hong, Sharon F.; Mann, J. Douglas; Hibbeln, Joseph R.; Ringel, Amit; Ramsden, Christopher E.

2014-01-01

Background Dietary linoleic acid (LA, 18:2n-6) lowering in rats reduces n-6 polyunsaturated fatty acid (PUFA) plasma concentrations and increases n-3 PUFA (eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) concentrations. Objective To evaluate the extent to which 12 weeks of dietary n-6 PUFA lowering, with or without increased dietary n-3 PUFAs, change unesterified and esterified plasma n-6 and n-3 PUFA concentrations in subjects with chronic headache. Design Secondary analysis of a randomized trial. Subjects with chronic headache were randomized for 12 weeks to: (1) average n-3, low n-6 (L6) diet; or (2) high n-3, low n-6 LA (H3-L6) diet. Esterified and unesterified plasma fatty acids were quantified at baseline (0 weeks) and after 12 weeks on a diet. Results Compared to baseline, the L6 diet reduced esterified plasma LA and increased esterified n-3 PUFA concentrations (nmol/ml), but did not significantly change plasma arachidonic acid (AA, 20:4n-6) concentration. In addition, unesterified EPA concentration was increased significantly among unesterified fatty acids. The H3-L6 diet decreased esterified LA and AA concentrations, and produced more marked increases in esterified and unesterified n-3 PUFA concentrations. Conclusion Dietary n-6 PUFA lowering for 12 weeks significantly reduces LA and increases n-3 PUFA concentrations in plasma, without altering plasma AA concentration. A concurrent increase in dietary n-3 PUFA for 12 weeks further increases n-3 PUFA plasma concentrations, but also reduces AA. PMID:24675168

A general strategy toward the rational synthesis of metal tungstate nanostructures using plasma electrolytic oxidation method

NASA Astrophysics Data System (ADS)

Jiang, Yanan; Liu, Baodan; Zhai, Zhaofeng; Liu, Xiaoyuan; Yang, Bing; Liu, Lusheng; Jiang, Xin

2015-11-01

A new method based on conventional plasma electrolytic oxidation (PEO) technology has been developed for the rational synthesis of metal tungstate nanostructures. Using this method, ZnWO4 and NiWO4 nanostructures with controllable morphologies (nanorods, nanosheets and microsheets) and superior crystallinity have been synthesized. It has been found that the morphology diversity of ZnWO4 nanostructures can be selectively tailored through tuning the electrolyte concentration and annealing temperatures, showing obvious advantages in comparison to traditional hydrothermal and sol-gel methods. Precise microscopy analyses on the cross section of the PEO coating and ZnWO4 nanostructures confirmed that the precursors initially precipitated in the PEO coating and its surface during plasma discharge process are responsible for the nucleation and subsequent growth of metal tungstate nanostructures by thermal annealing. The method developed in this work represents a general strategy toward the rational synthesis of metal oxide nanostructures and the formation mechanism of metal tungstate nanostructures fabricated by the PEO method is finally discussed.

Comparison method for uranium determination in ore sample by inductively coupled plasma optical emission spectrometry (ICP-OES).

PubMed

Sert, Şenol

2013-07-01

A comparison method for the determination (without sample pre-concentration) of uranium in ore by inductively coupled plasma optical emission spectrometry (ICP-OES) has been performed. The experiments were conducted using three procedures: matrix matching, plasma optimization, and internal standardization for three emission lines of uranium. Three wavelengths of Sm were tested as internal standard for the internal standardization method. The robust conditions were evaluated using applied radiofrequency power, nebulizer argon gas flow rate, and sample uptake flow rate by considering the intensity ratio of the Mg(II) 280.270 nm and Mg(I) 285.213 nm lines. Analytical characterization of method was assessed by limit of detection and relative standard deviation values. The certificated reference soil sample IAEA S-8 was analyzed, and the uranium determination at 367.007 nm with internal standardization using Sm at 359.260 nm has been shown to improve accuracy compared with other methods. The developed method was used for real uranium ore sample analysis.

Betaine and Secondary Events in an Acute Coronary Syndrome Cohort

PubMed Central

Lever, Michael; George, Peter M.; Elmslie, Jane L.; Atkinson, Wendy; Slow, Sandy; Molyneux, Sarah L.; Troughton, Richard W.; Richards, A. Mark; Frampton, Christopher M.; Chambers, Stephen T.

2012-01-01

Background Betaine insufficiency is associated with unfavourable vascular risk profiles in metabolic syndrome patients. We investigated associations between betaine insufficiency and secondary events in acute coronary syndrome patients. Methods Plasma (531) and urine (415) samples were collected four months after discharge following an acute coronary event. Death (34), secondary acute myocardial infarction (MI) (70) and hospital admission for heart failure (45) events were recorded over a median follow-up of 832 days. Principal Findings The highest and lowest quintiles of urinary betaine excretion associated with risk of heart failure (p = 0.0046, p = 0.013 compared with middle 60%) but not with subsequent acute MI. The lowest quintile of plasma betaine was associated with subsequent acute MI (p = 0.014), and the top quintile plasma betaine with heart failure (p = 0.043), especially in patients with diabetes (p<0.001). Top quintile plasma concentrations of dimethylglycine (betaine metabolite) and top quintile plasma homocysteine both associated with all three outcomes, acute MI (p = 0.004, <0.001), heart failure (p = 0.027, p<0.001) and survival (p<0.001, p<0.001). High homocysteine was associated with high or low betaine excretion in >60% of these subjects (p = 0.017). Median NT-proBNP concentrations were lowest in the middle quintile of plasma betaine concentration (p = 0.002). Conclusions Betaine insufficiency indicates increased risk of secondary heart failure and acute MI. Its association with elevated homocysteine may partly explain the disappointing results of folate supplementation. In some patients, especially with diabetes, elevated plasma betaine also indicates increased risk. PMID:22649561

Clinical features and hormonal profiles of cloprostenol-induced early abortions in heifers monitored by ultrasonography

PubMed Central

Lobago, Fikre; Gustafsson, Hans; Bekana, Merga; Beckers, Jean-François; Kindahl, Hans

2006-01-01

Background The present study describes the clinical features and plasma profiles of bovine pregnancy-associated glycoprotein 1 (bPAG1), the main metabolite of prostaglandin F2α (PG metabolite) and progesterone (P4) in heifers in which early abortions were induced. Methods Early abortions were induced in four heifers with cloprostenol and monitored by ultrasonography. Blood samples were collected and the plasma were analyzed for bPAG 1, P4 and PG metabolite. Results The foetal heartbeat rates varied from 170–186 beats per minute for all foetuses up to the date of cloprostenol treatment. Foetal death was confirmed within two days after cloprostenol treatment. Prior to cloprostenol injection, blood plasma concentrations of bPAG1, PG metabolite and P4 varied from 8.4 – 40.0 ng/mL, 158 – 275 pmol/L and 20.7 – 46.9 nmol/L, respectively. After the foetus expelled, the plasma level of bPAG1 began to decrease but the decrease was small and gradual. The estimated half-life of bPAG1 was 1.8 – 6.6 days. The plasma level of the PG metabolite started to have short lasting peaks (above 300 pmol/L) within three hours after cloprostenol treatment. The plasma concentrations of P4 dropped sharply to less than 4 nmol/L after 24 hours of cloprostenol injection. Conclusion The current findings indicated that after early closprostenol-induced foetal death, the plasma concentration of bPAG1 decreased gradually and showed a tendency of variation with the stages of pregnancy. PMID:17121683

Enantioselective analysis of ibuprofen in human plasma by anionic cyclodextrin-modified electrokinetic chromatography.

PubMed

Jabor, Valquíria A P; Lanchote, Vera L; Bonato, Pierina S

2002-09-01

This paper reports the development of a rapid method for the enantioselective analysis of the nonsteroidal anti-inflammatory drug ibuprofen in human plasma by capillary electrophoresis employing the anionic cyclodextrin-modified electrokinetic chromatography mode. Sample cleanup was carried out by acidification with HCl followed by liquid-liquid extraction with hexane:isopropanol (99:1 v/v). The complete enantioselective analysis was performed within 10 min, using 100 mmol L(-1) phosphoric acid/triethanolamine buffer, pH 2.6, containing 2.0% w/v sulfated beta-cyclodextrin as chiral selector; fenoprofen, another nonsteroidal anti-inflammatory drug, was used as internal standard. The calibration curves were linear over the concentration range of 0.25-125.0 microg mL(-1) for each enantiomer of ibuprofen. The mean recoveries for ibuprofen enantiomers were up to 85%. The enantiomers studied could be quantified at three different concentrations (0.5, 5.0 and 50.0 microg mL(-1)) with a coefficient of variation and relative error not higher than 15%. The quantitation limit was 0.2 microg mL(-1) for (+)-(S)- and (-)-(R)-ibuprofen using 1 mL of human plasma. The plasma endogenous compounds and other drugs did not interfere with the present assay. The analysis of real plasma samples obtained from a healthy volunteer after administration of 600 mg of racemic ibuprofen showed a maximum plasma level of 29.6 and 39.9 microg mL(-1) of (-)-(R)- and (+)-(S)-ibuprofen, respectively, and the area under plasma concentration-time curve AUC(0-infinity) (+)-(S)/AUC(0-infinity) (-)-(R) ratio was 1.87.

Simultaneous determination of thirteen different steroid hormones using micro UHPLC-MS/MS with on-line SPE system.

PubMed

Márta, Zoltán; Bobály, Balázs; Fekete, Jenő; Magda, Balázs; Imre, Tímea; Mészáros, Katalin Viola; Bálint, Mária; Szabó, Pál Tamás

2018-02-20

Ultratrace analysis of sample components requires excellent analytical performance in terms of limits of quantitation (LOQ). Micro UHPLC coupled to sensitive tandem mass spectrometry provides state of the art solution for such analytical problems. Using on-line SPE with column switching on a micro UHPLC-MS/MS system allowed to decrease LOQ without any complex sample preparation protocol. The presented method is capable of reaching satisfactory low LOQ values for analysis of thirteen different steroid molecules from human plasma without the most commonly used off-line SPE or compound derivatization. Steroids were determined by using two simple sample preparation methods, based on lower and higher plasma steroid concentrations. In the first method, higher analyte concentrations were directly determined after protein precipitation with methanol. The organic phase obtained from the precipitation was diluted with water and directly injected into the LC-MS system. In the second method, low steroid levels were determined by concentrating the organic phase after steroid extraction. In this case, analytes were extracted with ethyl acetate and reconstituted in 90/10 water/acetonitrile following evaporation to dryness. This step provided much lower LOQs, outperforming previously published values. The method has been validated and subsequently applied to clinical laboratory measurement. Copyright © 2017 Elsevier B.V. All rights reserved.

Concentrations of platinum group elements in 122 U.S. coal samples

USGS Publications Warehouse

Oman, C.L.; Finkelman, R.B.; Tewalt, S.J.

1997-01-01

Analysis of more than 13,000 coal samples by semi-quantitative optical emission spectroscopy (OES) indicates that concentrations of the platinum group elements (iridium, palladium, platinum, osmium, rhodium, and ruthenium) are less than 1 ppm in the ash, the limit of detection for this method of analysis. In order to accurately determine the concentration of the platinum group elements (PGE) in coal, additional data were obtained by inductively coupled plasma mass spectroscopy, an analytical method having part-per-billion (ppb) detection limits for these elements. These data indicate that the PGE in coal occur in concentrations on the order of 1 ppb or less.

Delivery of nicotine aerosol to mice via a modified electronic cigarette device

PubMed Central

Lefever, Timothy W.; Lee, Youn O.K.; Kovach, Alexander L.; Silinski, Melanie A.R.; Marusich, Julie A.; Thomas, Brian F.; Wiley, Jenny L.

2017-01-01

Background Although both men and women use e-cigarettes, most preclinical nicotine research has focused on its effects in male rodents following injection. The goals of the present study were to develop an effective e-cigarette nicotine delivery system, to compare results to those obtained after subcutaneous (s.c.) injection, and to examine sex differences in the model. Methods Hypothermia and locomotor suppression were assessed following aerosol exposure or s.c. injection with nicotine in female and male mice. Subsequently, plasma and brain concentrations of nicotine and cotinine were measured. Results Passive exposure to nicotine aerosol produced concentration-dependent and mecamylamine reversible hypothermic and locomotor suppressant effects in female and male mice, as did s.c. nicotine injection. In plasma and brain, nicotine and cotinine concentrations showed dose/concentration-dependent increases in both sexes following each route of administration. Sex differences in nicotine-induced hypothermia were dependent upon route of administration, with females showing greater hypothermia following aerosol exposure and males showing greater hypothermia following injection. In contrast, when they occurred, sex differences in nicotine and cotinine levels in brain and plasma consistently showed greater concentrations in females than males, regardless of route of administration. Discussion In summary, the e-cigarette exposure device described herein was used successfully to deliver pharmacologically active doses of nicotine to female and male mice. Further, plasma nicotine concentrations following exposure were similar to those after s.c. injection with nicotine and within the range observed in human smokers. Future research on vaped products can be strengthened by inclusion of translationally relevant routes of administration. PMID:28157590

3-compartment talaporfin sodium pharmacokinetic model by optimization using fluorescence measurement data from canine skin to estimate the concentration in interstitial space

NASA Astrophysics Data System (ADS)

Uno, Yuko; Ogawa, Emiyu; Aiyoshi, Eitaro; Arai, Tsunenori

2018-02-01

We constructed the 3-compartment talaporfin sodium pharmacokinetic model for canine by an optimization using the fluorescence measurement data from canine skin to estimate the concentration in the interstitial space. It is difficult to construct the 3-compartment model consisted of plasma, interstitial space, and cell because there is a lack of the dynamic information. Therefore, we proposed the methodology to construct the 3-compartment model using the measured talaporfin sodium skin fluorescence change considering originated tissue part by a histological observation. In a canine animal experiment, the talaporfin sodium concentration time history in plasma was measured by a spectrophotometer with a prepared calibration curve. The time history of talaporfin sodium Q-band fluorescence on left femoral skin of a beagle dog excited by talaporfin sodium Soret-band of 409 nm was measured in vivo by our previously constructed measurement system. The measured skin fluorescence was classified to its source, that is, specific ratio of plasma, interstitial space, and cell. We represented differential rate equations of the talaporfin sodium concentration in plasma, interstitial space, cell. The specific ratios and a converting constant to obtain absolute value of skin concentration were arranged. Minimizing the squared error of the difference between the measured fluorescence data and calculated concentration by the conjugate gradient method in MATLAB, the rate constants in the 3-compartment model were determined. The accuracy of the fitting operation was confirmed with determination coefficient of 0.98. We could construct the 3-compartment pharmacokinetic model for canine using the measured talaporfin sodium fluorescence change from canine skin.

Influence of storage conditions on in vitro stability of atrial natriuretic peptide and of anesthesia on plasma atrial natriuretic peptide concentration in cats.

PubMed

Heishima, Yasuhiro; Hori, Yasutomo; Chikazawa, Seishiro; Kanai, Kazutaka; Hoshi, Fumio; Itoh, Naoyuki

2016-08-01

OBJECTIVE To investigate the in vitro stability of atrial natriuretic peptide (ANP) in plasma samples under various storage conditions and the influence of anesthesia on plasma ANP concentration in cats. ANIMALS 1 cat with congestive heart failure and 5 healthy adult mixed-breed cats. PROCEDURES A plasma sample from the cat with heart failure was serially diluted, and dilutional parallelism of ANP concentration was evaluated. Plasma samples containing aprotinin or serum samples from the 5 healthy cats were kept at room temperature (27°C) for ≤ 12 hours. Plasma samples from the same healthy cats were stored at -70°, -20°, or 4°C for ≤ 14 days. Plasma samples were obtained from the healthy cats before and during isoflurane anesthesia. Plasma ANP concentrations were measured at a commercial laboratory by use of a human ANP chemiluminescence assay. RESULTS Intra- and interassay coefficients of variation were 1.5% and 2.5%, respectively, and dilutional parallelism was established. Although ANP concentration decreased by 82.4 ± 13.6% (mean ± SD) after sample storage for 12 hours at room temperature, this decrease was prevented by aprotinin. Plasma ANP concentrations were stable for 7 days at -20°C and for 14 days at -70°C. However, concentrations decreased markedly to 57.6 ± 6.9% at -20°C and to 18.0 ± 3.0% at 4°C after 14 days. Plasma ANP concentration decreased significantly in cats during anesthesia and was correlated with blood pressure. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that aprotinin should be added routinely in preparation of plasma samples from cats for measurement of ANP concentration, and those samples, if stored, should be frozen immediately at ≤ -20°C. General anesthesia or systemic blood pressure may affect plasma ANP concentration in cats.

Concentrations of Plasma Free Palmitoleic and Dihomo-Gamma Linoleic Fatty Acids Are Higher in Children with Abdominal Obesity.

PubMed

Aristizabal, Juan C; González-Zapata, Laura I; Estrada-Restrepo, Alejandro; Monsalve-Alvarez, Julia; Restrepo-Mesa, Sandra L; Gaitán, Diego

2018-01-01

Increased plasma free fatty acids (FFAs) are associated with cardiometabolic risk factors in adults with abdominal obesity (AO). However, this association remains controversial in children. This study analyzed plasma FFA concentration in children with and without AO. Twenty-nine children classified with AO were matched by age and sex with 29 non-obese individuals. Blood samples were collected after fasting for 10-12 h. Plasma concentration of glucose, insulin, triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were determined by automatized methods. FFAs were analyzed by gas chromatography. Children with and without AO had similar age (7.1 ± 2.6 vs. 7.2 ± 2.7 years; p > 0.05) but obese children showed higher ( p < 0.05) body mass index (BMI) (+4.3 kg/m²), systolic blood pressure (+5.1 mmHg), and insulin (+27.8 pmol/L). There were no significant differences in plasma total FFA concentration between groups (1.02 ± 0.61 vs. 0.89 ± 0.37 mmol/L; p > 0.05). However, children with AO had higher palmitoleic acid (0.94 vs. 0.70 wt %; p < 0.05) and dihomo-gamma linoleic acid (DHGL) (2.76 vs. 2.07 wt %; p < 0.05). Palmitoleic and DHGL acids correlated ( p < 0.05) with BMI ( r = 0.397; r = 0.296, respectively) and with waist circumference ( r = 0.380; r = 0.276, respectively). Palmitoleic acid correlated positively with systolic blood pressure ( r = 0.386; p < 0.05) and negatively with HDL-C (-0.572; p < 0.01). In summary, children with AO have higher plasmatic concentrations of free palmitoleic and DHGL fatty acids, which correlate with cardiometabolic risk factors.

Concentrations of Plasma Free Palmitoleic and Dihomo-Gamma Linoleic Fatty Acids Are Higher in Children with Abdominal Obesity

PubMed Central

González-Zapata, Laura I.; Estrada-Restrepo, Alejandro; Monsalve-Alvarez, Julia; Restrepo-Mesa, Sandra L.; Gaitán, Diego

2018-01-01

Increased plasma free fatty acids (FFAs) are associated with cardiometabolic risk factors in adults with abdominal obesity (AO). However, this association remains controversial in children. This study analyzed plasma FFA concentration in children with and without AO. Twenty-nine children classified with AO were matched by age and sex with 29 non-obese individuals. Blood samples were collected after fasting for 10–12 h. Plasma concentration of glucose, insulin, triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were determined by automatized methods. FFAs were analyzed by gas chromatography. Children with and without AO had similar age (7.1 ± 2.6 vs. 7.2 ± 2.7 years; p > 0.05) but obese children showed higher (p < 0.05) body mass index (BMI) (+4.3 kg/m2), systolic blood pressure (+5.1 mmHg), and insulin (+27.8 pmol/L). There were no significant differences in plasma total FFA concentration between groups (1.02 ± 0.61 vs. 0.89 ± 0.37 mmol/L; p > 0.05). However, children with AO had higher palmitoleic acid (0.94 vs. 0.70 wt %; p < 0.05) and dihomo-gamma linoleic acid (DHGL) (2.76 vs. 2.07 wt %; p < 0.05). Palmitoleic and DHGL acids correlated (p < 0.05) with BMI (r = 0.397; r = 0.296, respectively) and with waist circumference (r = 0.380; r = 0.276, respectively). Palmitoleic acid correlated positively with systolic blood pressure (r = 0.386; p < 0.05) and negatively with HDL-C (−0.572; p < 0.01). In summary, children with AO have higher plasmatic concentrations of free palmitoleic and DHGL fatty acids, which correlate with cardiometabolic risk factors. PMID:29301242

Add-On Effect of Probucol in Atherosclerotic, Cholesterol-Fed Rabbits Treated with Atorvastatin

PubMed Central

Keyamura, Yuka; Nagano, Chifumi; Kohashi, Masayuki; Niimi, Manabu; Nozako, Masanori; Koyama, Takashi; Yasufuku, Reiko; Imaizumi, Ayako; Itabe, Hiroyuki; Yoshikawa, Tomohiro

2014-01-01

Objective Lowering the blood concentration of low-density lipoprotein (LDL) cholesterol is the primary strategy employed in treating atherosclerotic disorders; however, most commonly prescribed statins prevent cardiovascular events in just 30% to 40% of treated patients. Therefore, additional treatment is required for patients in whom statins have been ineffective. In this study of atherosclerosis in rabbits, we examined the effect of probucol, a lipid-lowering drug with potent antioxidative effects, added to treatment with atorvastatin. Methods and Results Atherosclerosis was induced by feeding rabbits chow containing 0.5% cholesterol for 8 weeks. Probucol 0.1%, atorvastatin 0.001%, and atorvastatin 0.003% were administered solely or in combination for 6 weeks, beginning 2 weeks after the start of atherosclerosis induction. Atorvastatin decreased the plasma concentration of non-high-density lipoprotein cholesterol (non-HDLC) dose-dependently; atorvastatin 0.003% decreased the plasma concentration of non-HDLC by 25% and the area of atherosclerotic lesions by 21%. Probucol decreased the plasma concentration of non-HDLC to the same extent as atorvastatin (i.e., by 22%) and the area of atherosclerotic lesions by 41%. Probucol with 0.003% atorvastatin decreased the plasma concentration of non-HDLC by 38% and the area of atherosclerotic lesions by 61%. Co-administration of probucol with atorvastatin did not affect the antioxidative effects of probucol, which were not evident on treatment with atorvastatin alone, such as prevention of in vitro LDL-oxidation, increase in paraoxonase-1 activity of HDL, and decreases in plasma and plaque levels of oxidized-LDL in vivo. Conclusions Probucol has significant add-on anti-atherosclerotic effects when combined with atorvastatin treatment; suggesting that this combination might be beneficial for treatment of atherosclerosis. PMID:24810608

Concentration of Potassium in Plasma, Erythrocytes, and Muscle Tissue in Cows with Decreased Feed Intake and Gastrointestinal Ileus.

PubMed

Schneider, S; Müller, A; Wittek, T

2016-01-01

Healthy cows consume large amounts of potassium and a sudden loss in appetite can lead to hypokalemia. The routine method to evaluate potassium homeostasis is the measurement of the extracellular potassium in plasma or serum, but this does not provide information about the intracellular potassium pool. To evaluate potassium homeostasis by comparing the extracellular and intracellular potassium concentration in cows with reduced feed intake and gastrointestinal ileus. Twenty cows 1-3 days postpartum (group 1) and 20 cows with gastrointestinal ileus (group 2). Observational cross-sectional study. Plasma potassium was measured by using an ion-sensitive electrode. Intracellular potassium was measured in erythrocytes and muscle tissue (muscle biopsy) by using inductively coupled plasma optical emission spectroscopy. Cows of group 1 did not have hypokalemia. Overall cows with gastrointestinal ileus were hypokalemic (mean ± SD, 2.9 mmol/L ± 0.78), but potassium concentration in erythrocytes and muscle tissue was not lower than in postpartum cows. Intracellular potassium in erythrocytes varied very widely; group 1: 3497-10735 mg/kg (5559 ± 2002 mg/kg), group 2: 4139-21678 mg/kg (7473 ± 4034 mg/kg). Potassium in muscle tissue did not differ between group 1 (3356 ± 735 mg/kg wet weight) and group 2 (3407 ± 1069 mg/kg wet weight). No association between extracellular and intracellular potassium concentrations was detected. That measurement of plasma potassium concentration is not sufficient to evaluate potassium metabolism of cows. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Associations between intestinal mucosal function and changes in plasma zinc concentration following zinc supplementation1

PubMed Central

Wessells, K. Ryan; Hess, Sonja Y.; Rouamba, Noel; Ouédraogo, Zinewendé P.; Kellogg, Mark; Goto, Rie; Duggan, Christopher; Ouédraogo, Jean-Bosco; Brown, Kenneth H.

2015-01-01

Objectives Subclinical environmental enteropathy is associated with malabsorption of fats, carbohydrates, and vitamins A, B12 and folate; however, little information is available on mineral absorption. We therefore investigated the relationship between intestinal mucosal function (measured by the lactulose:mannitol permeability test and plasma citrulline concentration), and zinc absorption, as estimated by the change in plasma zinc concentration (PZC) following short-term zinc or placebo supplementation. Methods We conducted a randomized, partially-masked, placebo-controlled trial among 282 apparently healthy children 6–23 mo of age in Burkina Faso. After completing baseline intestinal function tests, participants received either 5 mg zinc, as zinc sulfate, or placebo, daily for 21 d. Results At baseline, mean ± SD PZC was 62.9 ± 11.9 µg/dL; median (IQR) urinary lactulose:mannitol (L:M) recovery ratio and plasma citrulline concentration were 0.04 (0.03 – 0.07) and 11.4 (9.0 – 15.6) µmol/L, respectively. Change in PZC was significantly greater in the zinc supplemented versus placebo group (15.6 ± 13.3 µg/dL vs. 0.02 ± 10.9 µg/dL; P < 0.0001), and was negatively associated with initial urinary L:M recovery ratio (−1.1 µg/dL per 50% increase in urinary L:M recovery ratio; P = 0.014); this latter relationship did not differ between supplementation groups (P = 0.26). Baseline plasma citrulline concentration was not associated with change in PZC. Conclusions Although altered intestinal permeability may reduce dietary zinc absorption, it likely does not undermine the efficacy of zinc supplementation, given the large increases in PZC following short-term zinc supplementation observed in this study, even among those with increased urinary L:M recovery ratios. PMID:23689263