Measurement by radioimmunoassay of unconjugated estriol in pregnancy serum.

Antisera to estriol 6--onjugates were tested for suitability in the direct radioimmunoassay of unconjugated estriol in extracts of pregnancy serum. Assessment of specificity through titration with competing steroids allowed a selection to be made within the group of antisera. The measurement was then standardized by checking the absence of analytical blank (solvent and sample blank) and the extent of binding variability associated with the use of charcoal-dextran as a separating agent. Validation was made by means of the usual recovery and dilution tests, and by a cross-comparison of analytical data obtained with different antisera; reproducibility of calibration curve and within-and between-assay variability was evaluated under routine conditions. The validity of the clinical information was assessed by assaying 202 samples randomly collected throughout normal pregnancy from the 16th week to term: both trend and levels of unconjugated estriol concentration were found to be in good agreement with the literature data.     

Direct radioimmunoassay for unconjugated estriol in pregnancy serum, with use of a radioiodinated derivative of estriol.

We describe a rapid and direct 125I-based radioimmunoassay for quantification of unconjugated (free) estriol in pregnancy serum. Estriol in serum is adsorbed onto a small column of Sephadex, thereby allowing its separation from proteins and interfering materials. A radioiodinated derivative of estriol (6-ketoestriol-6(o-carboxymethyl)oxime-[125I]tyrosine methyl ester) is added to the column, followed by a limiting amount of antiserum. After incubation, the antibody-bound hormone is separated by a buffer wash. The assay exhibits satisfactory recovery and parallelism, and the intra- and inter-assay coefficients of variation are less than 10%. The values obtained by using the assay correlate well (r = 0.97) with those from a comparison method in which solvent extraction and chromatographic purification are used.     

Nonchromatographic radioimmunoassay of unconjugated estriol in plasma, with polyethylene glycol as precipitant.

We describe a rapid, reliable radioimmunoassay for unconjugated estriol in plasma. Polyethylene glycol (Carbowax 6000) is used to separate antibody-bound and free steroid. The assay is sensitive (25 pg for standards), precise, and accurate. At high and low concentrations of estriol, intra-assay coefficients of variation were 7.1% and 7.6%, respectively, and inter-assay coefficients of variation were 7.2% and 10.0 %, respectively. Free [3H] estriol is not precipitated by polyethylene glycol. This radioimmunoassay of estriol, with a highly specific antiserum and with polyethylene glycol as the antibody precipitant, is a reliable one-day assay that is practical both for the clinical laboratory and the obstetrician.     

A simple radioimmunoassay for plasma cortisol.

A simple radioimmunoassay (RIA) for plasma cortisol is described which combines the advantages of (i) direct analysis of untreated plasma samples, (ii) use of solid-coupled anti-cortisol antibodies and (iii) use of a gamma-labelled radioligand. The reagents are relatively easily prepared and stable, and the analysis can be completed in 4 h. Inter-assay precision (C.V.) is 8-11%. Critical examination of specificity using high pressure liquid chromatography showed that 23-35% of the immunoassayable material in plasma was not cortisol. RIA results on samples collected under basal conditions were on average 40 nmol/l lower than fluorimetric results, while in insulin hypoglycaemia and synacthen (ACTH) stimulation tests, this difference increased to over 100 nmol/l. The RIA is technically more simple than fluorimetric, competitive-protein-binding, and many RIA methods, and can be used with advantage in the routine investigation of adrenocortical function. However, using the present antiserum, the RIA is not applicable to investigations on patients receiving metyrapone, nor in suspected cases of congenital adrenal hyperplasia.     

A simple radioimmunoassay of acebutolol in plasma

Antisera against acebutolol were produced in rabbits immunized by means of this drug conjugated with bovine serum albumin. These antisera were used to develop a method of radioimmunoassay for acebutolol. The plasma radioimmunoassay, described here, requires no extraction and is very easy to perform besides being quick, specific and sensitive. As little as 2.97 × 10^?9 mol/l of acebutolol can be detected. This radioimmunoassay is suitable for assaying the large number of samples usually measured in pharmacological studies.     

Method comparison studies for prostate specific antigen and unconjugated estriol immunoassays.

OBJECTIVE: Method comparison studies were performed in order to move a semi-automated prostate specific antigen (PSA) immunoassay and a manual unconjugated estriol (uE3) immunoassay to an automated chemistry immunoassay analyzer. The results of the two method comparison studies are compared. DESIGN: Serum samples collected on patients with physician orders for PSA or uE3 were assayed by both methods. PSA samples were assayed on a Hybritech Tandem Photon ERA and on two Beckman Coulter Access instruments. UE3 samples were assayed by RIA and on two Beckman Coulter Access instruments. Linear regression analysis was performed on both sets of data and within-run precision and dilution studies were performed on the PSA Access method. SETTING: Clinical chemistry laboratory, West Virginia University Hospitals Inc, Morgantown WV. RESULTS: PSA linear regression analysis for the two methods (ERA and Access 1) were y = 1.0008x + 0.0393, r = 0.9976, SE = 0.1319, n = 37 and (ERA and Access 2), y = 1.0019x + 0.0486, r = 0.9964, SE = 0.1632, n = 37. Within-run precision studies for both Access instruments produced acceptable coefficient variations and dilution study results were in PSA reportable range. uE3 linear regression analysis for the two methods (RIA and Access 1) were y = 1.4105x - 0.3741, r = 0.8696, SE = 0.8330, n = 33 and (RIA and Access 2) were y = 1.315x - 0.2292, r = 0.8643, SE = 0.7964, n = 33. CONCLUSION: The results of the method comparison studies for PSA were acceptable and the automated PSA immunoassay method was adopted. The results of the uE3 comparison studies did not show good correlation; the automated method was not adopted.     

A rapid competitive protein-binding assay of unconjugated oestradiol in late pregnancy plasma

A simple and rapid competitive binding method is described for the determination of unconjugated oestradiol in late pregnancy plasma. Macromolecules (oestrogen receptors) present in rabbit uterine cytosol were used as the binding protein. The bound and free fractions were separated by using dextran-charcoal suspension. The reliability of the method has been discussed. Sensitivity will allow determination of low levels of plasma oestradiol. The method can, therefore, be applied routinely in early and late pregnancies to monitor foeto-placental function.     

脂血标本对时间分辨荧光免疫分析法测定游离雌三醇水平的影响

目的探讨脂血标本对时间分辨荧光免疫分析法检测游离雌三醇水平的影响。方法收集男性呈正常和乳糜样外观的不同水平脂血标本,与不同水平的游离雌三醇定值血清混匀,制成混合血清,用时间分辨荧光分析法测定其游离雌三醇水平以评价不同乳糜样和正常外观脂血标本对游离雌三醇水平的影响。结果对于乳糜样外观标本,轻度脂血可使游离雌三醇水平增高,中度及高度脂血则使游离雌三醇水平降低,且对游离雌三醇水平的影响十分接近。外观正常的中度脂血对游离雌三醇水平无显著干扰。结论乳糜样外观脂血对时间分辨荧光分析法测定游离雌三醇存在不同的影响,进而影响唐氏筛查的准确度。     

A radioimmunoassay for neurotensin in human plasma

A specific radioimmunoassay for neurotensin in plasma has been developed with a sensitivity of 2 pmol/l of plasma. The antiserum was directed towards the amino terminal region of neurotensin and did not cross-react with other gastrointestinal peptides. Non-specific interference was eliminated and the sensitivity increased by extracting the plasma samples with ethanol prior to assay. Within- and between-assay coefficients of variation were 7.8% and 12% respectively. The mean plasma concentration of neurotensin in 30 fasting subjects was 29 ± 4 pmol/l. A mixed meal increased plasma neurotensin from 16 ± 2 to 53 ± 6 pmol/l at 2 h.     

A rapid radioimmunoassay method for plasma luteinizing hormone.

1. A rapid double antibody radioummunoassay method for the determination of plasma luteinizing hormone (hLH) is described. 2. The method involves preincubation of the anti-LH serum with the precipitating second antibody and incubation of this mixture with unknows and standards at room temperature overnight. The incubation tubes are then centrifuged, supernatants decanted and the precipitates counted. 3. A total of two working days is required to complete the assay and report the results. 4. This method is more rapid than the conventional ones currently used for the estimation of LH in blood.     

A simple radioimmunological method for the determination of plasma total oestriol during pregnancy.

A simple method for the determination of total oestriol in the plasma from late-term pregnant subjects using a specific radioimmunoassay is described.Over 30 samples can be evaluated within the working day and details of precision, accuracy, specificity and sensitivity are reported.A normal range with 120 samples from week 30 to term has been established.