Radioimmunoassay of plasma ouabain in healthy and pregnant individuals

Ouabain was recently isolated from human plasma, bovine hypothalamus and bovine adrenal in attempts to identify endogenous substances inhibiting the cell membrane sodium pump. A number of radioimmunoassays have been developed in order to study the clinical significance of ouabain. The results have been controversial with regard to the presence and chemical nature of plasma ouabain-like immunoreactivity. We have now measured ouabain in healthy and pregnant individuals using solid-phase extraction of plasma samples followed by a new radioimmunoassay with the extraordinary sensitivity of at least 2 fmol/tube (5 pmol/l). Plasma extracts, a previously isolated human plasma ouabain-like compound and bovine hypothalamic inhibitory factor displaced the tracer in parallel and eluted identically with ouabain in high-performance liquid chromatography. Plasma ouabain immunoreactivity was found to be much lower than reported previously: 12.6+/-1.3 pmol/l in healthy men (mean+/-s.e., n=20) and 9.4+/-0.7 pmol/l in women (n=14). In pregnant women (n=28) plasma ouabain concentration was 16.3+/-4.0 pmol/l during the first trimester, 18.8+/-4.3 pmol/l during the second trimester and 24.3+/-4.0 pmol/l during the third trimester (all P<0.01 compared with non-pregnant women). Plasma ouabain 3-5 days after the delivery was 13.6+/-1.1 pmol/l (n=10, P<0.05-0.01 compared with second and third trimesters). The pregnancy-related changes in the plasma concentrations of ouabain resembled those of cortisol. Therefore cortisol was measured from the same plasma samples and a significant positive correlation was found (r=0.512, P=0.006). The similar profiles of plasma ouabain and cortisol during pregnancy and their rapid decreases postpartum are consistent with the adrenal cortical origin of ouabain and also show that the secretions of these hormones are possibly under the control of same factors.

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Magnetic-Dispersive Solid Phase Extraction Based on Graphene Oxide–Fe3O4 Nanocomposites Followed by High Performance Liquid Chromatography-Fluorescence for the Preconcentration and Determination of Terazosin Hydrochloride in Human Plasma

Journal of Chromatographic Science ◽

10.1093/chromsci/bmz085 ◽

2019 ◽

Vol 58 (2) ◽

pp. 178-186 ◽

Cited By ~ 1

Author(s):

Yaser Pashaei ◽

Bahram Daraei ◽

Maryam Shekarchi

Keyword(s):

High Performance Liquid Chromatography ◽

Graphene Oxide ◽

Human Plasma ◽

High Performance ◽

Solid Phase ◽

Phase Extraction ◽

Plasma Samples ◽

Dispersive Solid Phase Extraction ◽

X Ray

Abstract In the present study, a facile modified impregnation method was employed to synthesize superparamagnetic graphene oxide–Fe3O4 (GO–Fe3O4) nanocomposites. Based on the GO–Fe3O4 as adsorbent, a simple and fast magnetic-dispersive solid phase extraction followed by high performance liquid chromatography with fluorescence detection (M-dSPE–HPLC–FL) method was established and validated for the preconcentration and determination of terazosin hydrochloride (TRZ) in human plasma samples. The obtained nanomaterials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometry. Different parameters affecting the extraction efficiency, such as sample pH, amount of sorbent, extraction time, elution solvent and its volume and desorption time, were evaluated and optimized. The linearity of the proposed method was excellent over the range 0.3–50.0 ng mL−1 with an acceptable coefficient of determination (R2 = 0.9989). The limit of quantification and limit of detection were found to be 0.3 and 0.09 ng mL−1, respectively, and the preconcentration factor of 10 was achieved. Intra- and inter-day precision expressed as relative standard deviation (RSD %, n = 6) were between 2.2–3.8% and 4.7–6.4%, respectively. Accuracy, estimated by recovery assays, was 97.7–106.6% with RSD ≤ 5.2%. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of TRZ in human plasma samples.

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Determination of trigonelline in human plasma by magnetic solid-phase extraction: a pharmacokinetic study

Nanomedicine ◽

10.2217/nnm-2020-0365 ◽

2021 ◽

Vol 16 (4) ◽

pp. 323-333

Author(s):

Neda Mohamadi ◽

Fariba Sharififar ◽

Mostafa Pournamdari ◽

Mehdi Ansari

Keyword(s):

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Human Plasma ◽

High Performance ◽

Solid Phase ◽

Reversed Phase ◽

Dose Finding ◽

Plasma Samples ◽

Chromatography Method ◽

Liquid Chromatography Method

Aim: To develop a novel method for the bioanalytical extraction of trigonelline (TRG) from human plasma samples using a magnetic nanocomposite and to evaluate its pharmacokinetic profile. Materials & methods: Magnetic bentonite/β-cyclodextrine (β-CD) nanoparticles, coupled with a validated ion-pairing reversed-phase high-performance liquid chromatography method, were used to determine TRG concentration from plasma samples following a single oral administration. Results: The developed reversed-phase high-performance liquid chromatography method was accurate, precise, specific, selective and reproducible. TRG showed rapid absorption, middle rate of elimination and mean residence time of ∼24 h. The data were best fitted on a two-compartment model in which tmax was 1.0 h, Cmax 0.115 μg/ml, area under the curve (AUC)0–24 1.72 μg/ml.h, Cl 0.0293 l/h/kg, t1/2α 0.79 h, t1/2β 13.68 h and ka 1.63 h-1. Conclusion: The findings of this study could provide useful information to promote the future study of TRG and aid optimal dose finding.

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Comparison of Three Sample Preparation Procedures for the Quantification of L-Arginine, Asymmetric Dimethylarginine, and Symmetric Dimethylarginine in Human Plasma Using HPLC-FLD

Journal of Analytical Methods in Chemistry ◽

10.1155/2018/6148515 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Anne Marie Voigt Schou-Pedersen ◽

Jens Lykkesfeldt

Keyword(s):

Sample Preparation ◽

Human Plasma ◽

Trichloroacetic Acid ◽

High Performance ◽

Asymmetric Dimethylarginine ◽

Solid Phase ◽

Plasma Samples ◽

Symmetric Dimethylarginine ◽

Limit Of Quantification ◽

Preparation Techniques

Increased asymmetric dimethylarginine (ADMA) in human plasma has been associated with reduced generation of nitric oxide, leading to atherosclerotic diseases. ADMA may therefore be an important biomarker for cardiovascular disease. In the present study, three sample preparation techniques were compared regarding the quantification of L-arginine and ADMA in human plasma: (A) protein precipitation (PP) based on aqueous trichloroacetic acid (TCA), (B) PP using a mixture of ammonia and acetonitrile, and (C) solid-phase extraction (SPE). The samples were analysed by using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The analytical performance of (A) was comparable with that of (C), demonstrating recoveries of >90%, coefficient of variations (CVs, %) of <8, and a resolution (Rs) between ADMA and symmetric dimethylarginine (SDMA) of 1.2. (B) was disregarded due to recoveries below 75%. (A) was validated with good results regarding linearity (>0.994), precision (<5%), and sensitivity (lower limit of quantification (LLOQ)) of 0.14 µM and 12 nM for L-arginine and ADMA, respectively. Due to the simplicity and speed of procedure (A), this approach may serve as preferred sample preparation of human plasma samples before HPLC-FLD in providing important information regarding elevated ADMA concentrations.

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A New Solid-Phase Extraction Method for Determination of Pantoprazole in Human Plasma Using High-Performance Liquid Chromatography

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2019.237 ◽

2019 ◽

Vol 7 (11) ◽

pp. 1757-1761 ◽

Cited By ~ 1

Author(s):

Dragica Zendelovska ◽

Emilija Atanasovska ◽

Kalina Gjorgjievska ◽

Kristina Pavlovska ◽

Krume Jakjovski ◽

...

Keyword(s):

Solid Phase Extraction ◽

Human Plasma ◽

Extraction Method ◽

High Performance ◽

Solid Phase ◽

Hplc Method ◽

Phase Extraction ◽

Good Precision ◽

Plasma Samples

BACKGROUND: A new simple, selective and accurate high-performance liquid chromatographic (HPLC) method utilising solid-phase extraction for the determination of pantoprazole in human plasma samples has been developed. AIM: The purpose of this paper was developing a new HPLC method suitable for the determination of pantoprazole in plasma samples, which enables simple and rapid isolation and concentration of the analysed drug.METHODS: The chromatographic separation was accomplished on a LiChroCart LiChrospher 60 RP select B column using a mobile phase composed of 0.2 % (V/V) water solution of triethylamine (pH 7) and acetonitrile (58:42, V/V) followed by UV detection was at 280 nm. The solid-phase extraction method using LiChrolut RP-18 (200 mg, 3 ml) was applied to the obtained good separation of investigated drug from endogenous plasma components. Best results were achieved when plasma samples were buffered with 0.1 mol/L KH2PO4 (pH 9) before extraction, eluted and reconstituted with acetonitrile and 0.001 mol/L NaOH after extraction, respectively. RESULTS: The standard calibration curves showed good linearity within the range of 25.0-4000.0 ng/mL with a correlation coefficient greater than 0.996. Retention times of pantoprazole and internal standard, lansoprazole was 4.1 and 6.0 min respectively. The limit of quantification was 25.0 ng/mL. For intra- and inter-day precision relative standard deviations ranged from 4.2 to 9.3%. The relative errors for stability investigations were ranged from 0.12 to -10.5%. CONCLUSION: This method has good precision and accuracy and was successfully applied to the pharmacokinetic and bioequivalence study of 40 mg pantoprazole in healthy volunteers.

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Maternal Plasma Pyridoxal 5′-Phosphate Concentration Is Inversely Associated with Plasma Cystathionine Concentration across All Trimesters in Healthy Pregnant Women

Journal of Nutrition ◽

10.1093/jn/nxz082 ◽

2019 ◽

Vol 149 (8) ◽

pp. 1354-1362

Author(s):

Maria F Mujica-Coopman ◽

Dayana R Farias ◽

Ana B Franco-Sena ◽

Juliana S Vaz ◽

Gilberto Kac ◽

...

Keyword(s):

Pregnant Women ◽

Carbon Metabolism ◽

Plasma Concentrations ◽

First Trimester ◽

Maternal Blood ◽

Maternal Plasma ◽

Third Trimester ◽

Metabolite Concentrations ◽

Mixed Regression ◽

One Carbon Metabolism

ABSTRACTBackgroundVitamin B-6 (B-6), in the form of pyridoxal 5′phosphate (PLP), is critical for one-carbon metabolism reactions and cellular function. Plasma PLP concentration decreases throughout pregnancy, but the functional consequences of this have not been studied. Plasma cystathionine is a sensitive indicator of suboptimal B-6 status in healthy adults.ObjectivesThe aim of this study was to determine the relation between plasma PLP and cystathionine concentrations, and to assess longitudinal changes in plasma concentrations of metabolites of one-carbon metabolism, including total homocysteine (tHcy), cysteine, methionine, glycine, serine, and glutathione, over the course of pregnancy.DesignThis was a prospective cohort study of 186 healthy Brazilian pregnant women (20–40 y). Plasma PLP and metabolite concentrations were quantified in fasting maternal blood samples collected between 5–13, 20–26, and 30–36 weeks of gestation. Linear mixed regression models were used to determine the association of 1) first-trimester PLP tertiles, and 2) the variation of PLP concentration throughout pregnancy, with related metabolite concentrations across weeks of gestation.ResultsMedian (IQR) PLP concentration decreased from 36.2 (29.2–44.5) to 21.0 (15.9–26.0) to 16.8 (12.9–21.4) nmol/L in the first, second, and third trimester, respectively, whereas cystathionine concentration increased from 63.2 (49.7–78.9) to 122 (98.0–167) to 143 (114–193) nmol/L, respectively (both P < 0.001). The variation of PLP throughout pregnancy was inversely associated with cystathionine concentration across weeks of gestation, after adjusting for confounding factors; β (95% CI) = −0.387 (−0.752, −0.219), P = 0.04. This association significantly differed by trimester and was strongest in the third trimester. Plasma concentrations of glycine, serine, methionine, cysteine, and tHcy decreased, and that of glutathione increased, between the first and second trimesters (all P < 0.05).ConclusionsThe variation of PLP concentration predicted cystathionine concentration throughout pregnancy. Increases in plasma cystathionine across trimesters may reflect maternal intracellular B-6 deficiency.

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Pregnancy increases urinary loss of carnitine and reduces plasma carnitine in Korean women

British Journal Of Nutrition ◽

10.1079/bjn20041403 ◽

2005 ◽

Vol 93 (5) ◽

pp. 685-691 ◽

Cited By ~ 17

Author(s):

Sang-Woon Cho ◽

Youn-Soo Cha

Keyword(s):

Urinary Excretion ◽

Pregnant Women ◽

Plasma Concentrations ◽

Late Pregnancy ◽

First Trimester ◽

Korean Women ◽

Third Trimester ◽

Carnitine Level ◽

Plasma Carnitine ◽

Total Carnitine

This study compared plasma and urinary carnitine concentrations in pregnant and non-pregnant Korean women. The subjects were fifty pregnant women and thirty non-pregnant women aged 24–28 years. During the first trimester, dietary carnitine intakes in the pregnant women were much lower than in non-pregnant women (70·00 (sd 29·22) μmol/d), but over the course of pregnancy carnitine intake increased from 44·64 (sd 24·84) μmol/d during the first trimester to 96·11 (sd 36·56) μmol/d during the third trimester. Pregnant women had a significantly lower plasma carnitine concentration than non-pregnant women. Plasma concentrations of non-esterified carnitine, acid-soluble acylcarnitine and total carnitine were significantly lower during the second and third trimesters than the first. Plasma acid-insoluble acylcarnitine levels, which tended to be higher in the non-pregnant women compared with the pregnant women, increased significantly as gestation proceeded. The urinary excretion of non-esterified carnitine, acid-soluble acylcarnitine and total carnitine was significantly higher in the pregnant women during the first and second trimesters than in non-pregnant women and decreased significantly as gestation proceeded. We found that there was a significant decrease in plasma carnitine level even though dietary carnitine intake increased as gestation proceeded. The low urinary excretion of carnitine in late pregnancy may be caused by an increased demand during pregnancy.

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Bioanalytical method development and validation of simultaneous analysis of telmisartan and hydrochlorthiazide in human plasma using LC-MS/MS

International Journal of Bioassays ◽

10.21746/ijbio.2016.03.003 ◽

2016 ◽

Vol 5 (03) ◽

pp. 4862 ◽

Cited By ~ 1

Author(s):

Mathew George* ◽

Lincy Joseph ◽

Arpit Kumar Jain ◽

Anju V.

Keyword(s):

Human Plasma ◽

Retention Time ◽

High Performance ◽

Method Development ◽

Matrix Effects ◽

Solid Phase ◽

Internal Standard ◽

Assay Method ◽

Buffer System ◽

Internal Standards

A simple, sensitive, rapid and economic high performance thin layer chromatographic method and a mass spectroscopic assay method has been developed for the quantification of telmisartan and hydrochlorthiazide combination in human plasma. The internal standards and analytes were extracted from human plasma by solid-phase extraction with HLB Oasis1cc (30mg) catridges. The scanning and optimization for the samples are done using methanol: water (50:50). The samples were chromatographed using reverse phase chromatography with C-18 column of different manufacturers like Ascentis C18 (150×4. 6, 5µ) using the buffer system Acetonitrile: Buffer (80:20%v/v) which consist of 2±0. 1Mm ammonium format at a flow rate of 0. 7ml/min at a column oven temperature 35±10c. The internal standard used was hydrochlorthiazide13c1, d2 and telmisartand3. The extraction techniques include conditioning, loading, washing and elution, drying followed by reconstitution of the dried samples. The volume injected was 10µl with the retention time of 3-4 min for telmisartan, 1-2 min for hydrochlorthiazide and for the internal standards the retention time was 3-4 min for telmisartand3 and 1-2 min for hydrochlorthiazide c13d2. The rinsing solution was Acetonitrile: HPLC grade water in the ratio (50:50). The above developed method was validated using various parameters like selectivity and sensitivity, accuracy and precision, matrix effects, % recovery and various stability studies. The method was proved to be sensitive, accurate, precise and reproducible. The preparation showed high recovery for the quantitative determination of telmisartan and hydrochlorthiazide in human plasma.

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Plasma γ-Globin Gene Expression Suggests that Fetal Hematopoietic Cells Contribute to the Pool of Circulating Cell-Free Fetal Nucleic Acids during Pregnancy

Clinical Chemistry ◽

10.1373/clinchem.2003.030064 ◽

2004 ◽

Vol 50 (4) ◽

pp. 689-693 ◽

Cited By ~ 21

Author(s):

Tuangsit Wataganara ◽

Erik S LeShane ◽

Angela Y Chen ◽

Lynn Borgatta ◽

Inga Peter ◽

...

Keyword(s):

Nucleic Acids ◽

Pregnant Women ◽

Globin Gene ◽

Hematopoietic Cells ◽

First Trimester ◽

Maternal Plasma ◽

Plasma Samples ◽

Globin Mrna ◽

Reverse Transcription Pcr ◽

Gapdh Mrna

Abstract Background: Reports of placental mRNA sequences in the plasma of pregnant women suggest that the placenta is the predominant source of cell-free fetal nucleic acids in maternal plasma during pregnancy. We developed an assay for γ-globin mRNA concentrations to determine whether hematopoietic cells also contribute to the pool of fetal mRNA in maternal plasma. Methods: Frozen paired plasma samples obtained from 40 women before and within 20 min after elective first-trimester termination of pregnancy (TOP) were analyzed. Fresh plasma samples from eight nonpregnant individuals were included as controls. Plasma γ-globin mRNA was measured by use of real-time reverse transcription-PCR and analyzed with gestational age. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA was used to confirm the presence of cell-free RNA in each sample. Results: γ-Globin and GAPDH mRNA sequences were detected in every plasma sample. The concentrations of both messages were significantly increased in pregnancy (P <0.01). The concentrations of γ-globin mRNA were decreased in most women after TOP, but γ-globin mRNA was increased in some patients when TOP was performed later than 9 weeks of gestation. Conclusions: γ-Globin mRNA sequences can be detected and measured in fresh and frozen plasma samples. Plasma γ-globin and GAPDH mRNA concentrations are affected by pregnancy. The increased posttermination γ-globin mRNA concentrations seen in some patients suggest that the source of this message is fetal hematopoietic cells. Further study in pregnant women after 9 weeks of gestation is necessary to evaluate the potential of γ-globin mRNA as a marker for fetomaternal hemorrhage.

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