The determination of oestradiol and oestrone in the plasma of the domestic fowl by a method involving the use of labelled derivatives

1. A method involving the use of triple-labelled derivatives has been developed for the determination of total oestrone and oestradiol in the plasma of the domestic fowl. The double-labelling technique devised by Svendsen (1960) for the determination of free oestrogens in human plasma was modified to enable the total oestrogen recovery to be determined for each sample. 2. [6,7−3H2]Oestradiol-17β is added to the plasma samples (1–10ml.), which are hydrolysed with acid and the phenolic steroids then extracted and partially purified. The extract is esterified with iodobenzene-p[35S]-sulphonyl chloride of high specific activity. After addition of standard oestrogen [131I]iodobenzene-p-sulphonates the esters are finally purified by paper chromatography. 3. The oestrogens are determined by comparing the 3H/35S and 131I/35S ratios in the purified esters with similar ratios of appropriate standards. 4. With this procedure the recoveries of oestrone and oestradiol after hydrolysis were 70–85% and 72–84% respectively, and after hydrolysis and preliminary purification 38–53% and 39–51% respectively. With this procedure up to 500ng. of oestradiol can be determined. The sensitivity of the technique for oestrone is 3·0ng. and for oestradiol 2·1ng. 5. The ranges of oestradiol and oestrone concentrations found in six plasma samples were 8·3–21·4ng./ml. and 15·2–31·6ng./ml. respectively.

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Improvements in the determination of the turnover rate of plasma thyroxine in avian species: application to the Japanese quail

Journal of Endocrinology ◽

10.1677/joe.0.1140191 ◽

1987 ◽

Vol 114 (2) ◽

pp. 191-198 ◽

Cited By ~ 2

Author(s):

E. J. Cookson ◽

J. Glover

Keyword(s):

Japanese Quail ◽

Half Life ◽

Turnover Rate ◽

Specific Activity ◽

Simple Procedure ◽

High Specific Activity ◽

Future Application ◽

Sodium Thiocyanate ◽

Plasma Samples

ABSTRACT The disappearance of the thyroid hormone thyroxine (T4) from plasma in fully grown male Japanese quail can be described as a first order process with a rate constant of 0·178 ± 0·013/h (mean±s.e.m., n = 8), which represents a half-life of 3·90 h. A small amount of [125I]T4 in relation to total circulating T4 was injected i.v. into Japanese quail and plasma samples were taken at appropriate time-intervals for the determination of residual plasma radioactivity. The rate of disappearance of [125I]T4 was subsequently equated to the turnover rate of the endogenous hormone. Previous methods were modified to overcome problems arising from possible disturbance of plasma T4 metabolism, recirculation of radiolabelled iodide, and to purify the [125I]T4 from the plasma samples. By using labelled T4 of very high specific activity, the amount of [125I]T4 administered was kept much smaller than has been used in previous studies on Japanese quail, thus limiting any interference with plasma T4 dynamics. To minimize any disturbance of plasma T4 metabolism, only four blood samples were taken, at three-hourly intervals after the injection of [125I]T4. The rapid turnover of T4 produced a large amount of labelled inorganic iodide, the re-entry of which into the plasma T4 pool was inhibited by s.c. administration of sodium thiocyanate 1 h before injection of[125I]T4. Assay of the true [125I]T4 turnover was significantly improved over that used in previous studies by purifying the [125I]T4 from the plasma samples chromatographically. The samples were applied to small Sephadex G-25 columns with sodium hydroxide (0·1 mol/l) as the eluant. This simple procedure clearly separated the [125I]T4 from the other radioiodinated plasma components such as free iodide, non-hormonal iodinated proteins and triiodothyronine (T3), thus enabling a more accurate assessment of the residual labelled T4 concentration in the plasma and hence the T4 half-life. The future application of this method to the study of plasma T4 turnover under various experimental conditions is discussed and the possible involvement of T4 turnover studies in the assessment of T4 to T3 conversion is considered. J. Endocr. (1987) 114, 191–198

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THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR OXYTOCIN: RADIO-IODINATION, ANTIBODY PRODUCTION AND SEPARATION TECHNIQUES

Journal of Endocrinology ◽

10.1677/joe.0.0460269 ◽

1970 ◽

Vol 46 (2) ◽

pp. 269-278 ◽

Cited By ~ 35

Author(s):

T. CHARD ◽

M. J. KITAU ◽

J. LANDON

Keyword(s):

Lymph Node ◽

Human Plasma ◽

Rapid Method ◽

Ammonium Sulphate ◽

Antibody Production ◽

Specific Activity ◽

High Specific Activity ◽

Separation Techniques ◽

Ammonium Sulphate Precipitation

SUMMARY A simple and rapid method is described for labelling oxytocin with 131I at a high specific activity. This method is compared with those of previous workers. A satisfactory antiserum has been raised by direct intra-lymph node injection of oxytocin adsorbed to carbon microparticles. A number of methods for separating antibody-bound from free oxytocin are described, and reasons given for preferring a procedure using ammonium sulphate precipitation. These data form the basis for developing a radioimmunoassay intended for the determination of oxytocin in human plasma.

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Optimizationvia experimental design of an SPE-HPLC-UV-fluorescence method for the determination of valsartan and its metabolite in human plasma samples

Journal of Separation Science ◽

10.1002/jssc.200600093 ◽

2006 ◽

Vol 29 (15) ◽

pp. 2265-2283 ◽

Cited By ~ 24

Author(s):

Gorka Iriarte ◽

Nerea Ferreirós ◽

Izaskun Ibarrondo ◽

Rosa Maria Alonso ◽

Miren Itxaso Maguregi ◽

...

Keyword(s):

Experimental Design ◽

Human Plasma ◽

Fluorescence Method ◽

Plasma Samples ◽

Uv Fluorescence ◽

Human Plasma Samples

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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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Simultaneous determination of sertraline, imipramine and alprazolam in human plasma samples using headspace solid phase microextraction based on a nanostructured polypyrrole fiber coupled to ion mobility spectrometry

Analytical Methods ◽

10.1039/c9ay02001b ◽

2020 ◽

Vol 12 (7) ◽

pp. 930-937 ◽

Cited By ~ 1

Author(s):

Erfan Barati ◽

Naader Alizadeh

Keyword(s):

Simultaneous Determination ◽

Human Plasma ◽

Ion Mobility Spectrometry ◽

Ion Mobility ◽

Solid Phase Microextraction ◽

Solid Phase ◽

Electrochemical Process ◽

Plasma Samples ◽

Spme Fiber

PPy-DBS was synthesized by an electrochemical process and used as a HS-SPME fiber for determination of antidepressants in plasma without derivatization steps.

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Spectrofluorimetric Determination of Warfarin Sodium by Using N1-Methylnicotinamide Chloride as a Fluorigenic Agent

Journal of AOAC International ◽

10.1093/jaoac/88.2.455 ◽

2005 ◽

Vol 88 (2) ◽

pp. 455-461 ◽

Cited By ~ 4

Author(s):

Mohamed A El Dawy ◽

Mokhtar M Mabrouk ◽

Riad A El Barbary

Keyword(s):

Aqueous Solutions ◽

Human Plasma ◽

Plasma Samples ◽

Spiked Human Plasma ◽

Human Plasma Samples ◽

Warfarin Sodium ◽

Spectrofluorimetric Method ◽

Spectrofluorimetric Determination ◽

Methylene Groups

Abstract A spectrofluorimetric method is described for the determination of drugs containing active methylene groups adjacent to carbonyl groups. The method was applied successfully to the determination of warfarin sodium in laboratory-prepared mixtures, in commercial tablets, and in spiked human plasma samples. Finally, the method was applied to the determination of the steady-state concentration of warfarin sodium in the blood of a hospitalized patient. The method involves the reaction of warfarin sodium with 0.2 ml (0.4 × 10−3M) N1-methylnicotinamide chloride reagent in the presence of 3 mL 1.0N NaOH and cooling in ice for 8 min, followed by adjustment of the pH to 2.0, using formic acid and heating for 4 min, whereby a highly fluorescent reaction product is produced. The optimal wavelengths of excitation and emission were determined by using a synchronous wavelength search and found to be 284 and 354 nm, respectively. The standard curves were linear over a concentration range of 50–1500 ng/mL in both aqueous solutions and spiked human plasma samples. The mean recoveries (± standard deviation) were 101.157 (±1.33) and 95.73 (±1.88%) for aqueous solutions and spiked human plasma samples, respectively. The method showed good specificity and precision. The proposed method is simple and economical because of its minimal instrumentation and chemicals requirements. Nevertheless, it is highly sensitive, specific, and reproducible. Accordingly, it is suitable for quality-control applications, drug monitoring, and bioavailability and bioequivalency studies.

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Eine Methode zur qualitativen und quantitativen Bestimmung von drei Juvenilhormonen von Insekten

Zeitschrift für Naturforschung C ◽

10.1515/znc-1974-3-412 ◽

1974 ◽

Vol 29 (3-4) ◽

pp. 161-168 ◽

Cited By ~ 41

Author(s):

K. H. Trautmann ◽

A. Schuler ◽

M. Suchý ◽

H.-K. Wipf

Keyword(s):

Quantitative Determination ◽

Specific Activity ◽

High Specific Activity ◽

Ether Extract ◽

Qualitative And Quantitative ◽

Work Up ◽

First Time ◽

Very High ◽

Tenebrio Molitor Larvae

Abstract A method is presented permitting the qualitative and quantitative determination of all three presently known hormones (JH1-3). The determination is based on the method of radioactive isotope dilution, whereby a very small known amount of tritium-labelled JH-1 is added to the ether extract of the particular species. The addition of radioactive JH-1 permits the isolation of all three hormones, because of their similar behaviour during the chosen work up. The quantitative determination was carried out by gas chromatography and the identification was confirmed with the help of retention-times and GC-MS combination. The method was checked by using an extract of Hyalophora cecropia. For the first time methyl 10,11-epoxy-3,7,11-trimethyl-2-trans-6-trans-dodecadienoate (JH-3) could also be identified as the juvenile hormone of Melolontha melolontha. In Vanessa io larvae, Tenebrio molitor larvae and adults and in Musca domestica larvae none of the three known hormones could be detected. The preparation of JH-1 labelled with tritium in the methyl group of the ester was accomplished with very high specific activity (4.34 Ci/mmol) of the tritiated acid with diazomethane.

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Development and validation of a UPLC–MS/MS method for simultaneous determination of LBPT and its metabolites in human plasma

Bioanalysis ◽

10.4155/bio-2019-0289 ◽

2020 ◽

Vol 12 (4) ◽

pp. 211-220

Author(s):

Mengyi Wu ◽

Aijing Liu ◽

Quankun Zhuang ◽

Ranran Jia ◽

Yinping Zhou ◽

...

Keyword(s):

Clinical Trial ◽

Human Plasma ◽

Tandem Mass ◽

Plasma Samples ◽

Triple Quadrupole ◽

Multiple Reactions ◽

The Us ◽

Us Fda ◽

Development And Validation

Aim: A UPLC–MS/MS method was developed to determine LBPT as well as its four metabolites in human plasma to support the clinical study aiming to evaluate the efficacy of LBPT tablet in patients undergoing hip/knee replacement. Methodology: Plasma samples were prepared by protein precipitation and then separated on a C18 analytical column using (A) acetonitrile (B) 0.1% formic acid and 10 mM ammonium formate in water. The detection was performed on a triple quadrupole tandem mass spectrometer in positive electrospray ionization using multiple reactions monitoring mode. Results & conclusion: The method has been validated in accordance with the US FDA guidelines and was applied to the measurement of five analytes in human plasma samples from a Phase II clinical trial.

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