摘要:

A radioimmunoassay method for the direct measurement of cortisol in plasma after precipitation of the proteins with ethanol is described. Utilizing a specific antiserum against cortisol, with minimal or no cross reaction with other steroids, cortisol was meas-red accurately in a volume of 0.001 ml of plasma. The range of levels that could be measured per ml of plasma varied from 10 to 500 ng. The mean value of plasma cortisol at 8 a. m. obtained in twelve subjects by this method was about half the mean levels reported by another competitive protein binding assay.

ISSN:0003-2719    

DOI:10.1080/00032717208069558

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

We have compared the results obtained for plasma cortisol when two methods were used to measure this steroid. The first method, a Competitive protein binding (CPB) assay, used transcortin as binding protein for cortisol. The second method is a radioimmunoassay (RIA) utilizing as binding reagent, a specific antibody against cortisol. Nineteen samples were tested covering a wide range of values. The CPB assay consistently overestimated the levels of plasma cortisol compared to the RIA method.

ISSN:0003-2719    

DOI:10.1080/00032717208069559

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

This report describes a radioimmunoassay method for measuring unconjugated plasma testosterone (T) and its application to the measurement of T in murine plasma. The parameters of assay reliability, sensitivity, and accuracy were established. Di-hydrotestosterone, the only steroid which showed significant cross-reaction with the testosterone antibody used, was not found in significant quantities in male mice of 19 inbred strains examined. This suggested that chromatographic separation of T from other plasma steroids was unnecessary for the measurement of T in males of this species. Biological levels of T in normal adult male mice of 19 inbred strains showed a range of 0.64 to 21.9 ng/ml plasma and a mean of 5.10 ng/ml. Castration reduced testosterone levels to about 4% of the normal level; castration plus adrenalectomy reduced testosterone to levels below the sensitivity of this method. These investigations demonstrated the validity and reliability of this method for measuring uncanjugated plasma T in male mice.

ISSN:0003-2719    

DOI:10.1080/00032717208069560

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A method is presented for simultaneous determination of submicrogram quantities of testosterone and epitestosterone in human plasma. These steroid alcohols are determined as O-methyldichlorotetrafluoroketals (2,4 MCFK) by electron capture detection. Ten to 20 ml. of plasma, with 4-I4C testosterone added for recovery, is extracted and purification is achieved by thin-layer chromatography (TLC). The hemi-ketals, which are formed by addition of 1, 3-dichloro-l,1,3, 3-tetrafluoroacetone are quantitatively converted to methyl ethers by diazomethane, Plasma testosterone, separated as testosterone-2,4 MCFK was collected from gas chromatograph and identified by its ultraviolet (uv) absorption. The infrared (ir) spectra of testosterone, epitestosterone and their 2,4 MCFK derivatives are reported.

ISSN:0003-2719    

DOI:10.1080/00032717208069561

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

3-Ketosteroid methoximes (MO derivatives) undergo a degradation when injected into columns that contain acidic materials or supports with acidic sites. Degradation products can usually not be isolated; they result from a Beckmann fission reaction. The extent of sample loss is dependent on the amount of acidic material (pyridine hydrochlo-ride), and decreases with time as the column is “healed” by sweeping or silylation treatment. Lanost-8-ene-3-one MO derivative, where the methoxime group is adjacent to a tertiary carbon atom, gives an unsaturated nitrile by Beckmann fission. An appropriate analytical technique was developed to prevent sample loss. About 1–3 cm of 10% coated support at the head of the column will prevent permanent damage to the column; the solution of the analytical sample should also contain an excess of silylation reagent. When this is done, no sample loss is observed in GC studies of adrenocortical steroid hormones as MO-TMS derivatives.

ISSN:0003-2719    

DOI:10.1080/00032717208069562

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A kinetic method for the determination of creatinine in 50 ul of serum or plasma, without deproteinization or pre-treatment, at rate of 50 to 100 samples an hour is described. The precision is better than2%(CV) in the normal range and the recovery very close to 100%. The method is linear at least up to 10−3M(11.3 mg/lOOml) and can be standardized with aqueous creatinine solutions. Glucose and proteins do not interfere with the reaction.

ISSN:0003-2719    

DOI:10.1080/00032717208069563

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Mercury and silver were determined by precipitation from aqueous solution with β amino-naphthylamido thioglycolic acid (thionalid). The metallic thionalidate phases were separated, dissolved in ethanol and analyzed by coulometric titration of the thionalid with electrogenerated iodine.

ISSN:0003-2719    

DOI:10.1080/00032717208069564

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

An inverse voltametric method is described for determining traces of aluminum in beryllium and its compounds. The method is based on the electrochemical oxidation of the aluminum solochrome violett RS complex at a carbon paste electrode. The determination can be carried out in the ppm range without previous separation of other trace elements.

ISSN:0003-2719    

DOI:10.1080/00032717208069565

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The performance of a liquid-membrane electrode using a synthesized ligand in p-nitroethylbenzene as membrane component is described. Selectivities, working range, lifetime, pH-dependence, and dependence on the dielectric constant of the membrane solvent are discussed. The electrode makes possible the measurement of calcium ion activities in the range of 10−1M to 10−5M In unbuffered systems with a selectivity of calcium over sodium and magnesium of 175 and 33,000 respectively. The selectivity constants of the cell discussed are heavily influenced by the dielectric constant of the membrane solvent.

ISSN:0003-2719    

DOI:10.1080/00032717208069566

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A system is described for the non-flame atomisation of mercury, using sample heating pulses of a few microseconds duration. The rapid sample atomisation thus obtained leads to good analytical sensitivity; it also provides a technique for distinguishing between, and separately measuring, inorganic and organically-bound mercury.

ISSN:0003-2719    

DOI:10.1080/00032717208069567

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor