Data Processing for Radioimmunoassay Standard Curve Using Microcomputer: A New Basic Program for Weighted Logit-Log Transformation

A new BASIC program of the weighted linear, quadratic and cubic logit-log regression methods for data processing of radioimmunoassay standard curve was developed using a microcomputer. Using this program, three regression analyses are calculated and the table for root mean square of residuals in each regression are shown for the selection of the regression method. The data of three radioimmunoassays of human pancreatic enzymes and pancreatic secretory trypsin inhibitor were examined by this program and compared with those processed by the four parameter logistic method. The weighted cubic logit-log regression showed better fit in radioimmunoassays of human pancreatic enzymes with larger molecular weights. The present program is useful and practicable for its simplicity and accuracy.

Iterative weighted regression analysis of logit responses: a computer program for analysis of bioassays and immunoassays

A program, WRANL, is described for the analysis of immunoassays or bioassays which have a logistic dose-response relationship. Responses are transformed to logits and iterative weighted regression analysis is used to obtain log dose-logit response lines for all preparations compared in an assay. Potency estimates of preparations relative to the standard preparation are available for both unweighted and weighted regression analyses together with detailed analysis of variance, estimates of slope and other relevant parameters. The general comparisons of dose-response relationships produced by the program are a feature of particular interest. However, an option which suppresses the more general output is available if the program is to be used for analysis of a 'screening' assay comparing single dilutions or doses of test samples with a standard curve. Data input is designed to permit immediate running of the program by junior personnel. Data output is designed to facilitate record keeping.

Gentamicin assay: comparison of an adapted EMIT method and an RIA method

The EMIT technique for gentamicin assay adapted to the Centrifichem-300 system was compared with an established RIA procedure. EMIT results correlated very well with the results obtained by the RIA method (r = 0.976, N = 48). For the adapted EMIT assay, the interassay coefficient of variation was 4-8% and for the RIA method 6-14%. Several possible interfering agents were investigated, of which only carbenicillin showed interference in both assays. Our data indicate that the EMIT technique exhibits adequate precision and accuracy for routine gentamicin determinations.

Relationship of cardiac oxygen usage, adenosine content, and coronary resistance in dogs

Analysis of the relationships between cardiac oxygen usage (MVO2), cardiac muscle adenosine levels([Ado]), and coronary vascular resistance (R) in open-chest, anesthetized dogs tested the hypothesis that adenosine is a physiological regulator of coronary flow. Experiments using each dog as its own control showed that [Ado] varied directly with MVO2 as the latter changed spontaneously or in response to atrial pacing, paired pacing, aortic constriction, of beta-adrenergic blockade. In turn, R varied inversely with changes in [Ado]. Stimulating MVO2 with isoproterenol significantly increased the slope of the regression of [Ado] on MVO2 as well as of R-1 on [Ado]. The effect of beta-adrenergic stimulation on [Ado] is unexplained, but its effect on R-1 seems to reflect the combined effects of adenosine and direct beta-adrenergic coronary relaxation. These results support the hypothesis that adenosine mediates the coronary flow responses to changes in MVO2.

Serum levels of butorphanol by radioimmunoassay

A radioimmunassay was developed for the analysis of butorphanol in human serum. The procedure involves extraction of serum with hexane containing 2% isoamyl alcohol, followed by evaporative solvent removal and radioimmunoassay of the reconstituted residue. The antibody significantly cross-reacts with unidentified butorphanol metabolites but not with two known metabolites, hydroxybutorphanol and norbutorphanol. Extraction eliminated interference from the butorphanol metabolites normally present in serum. The antibody also cross-reacts with pentazocine and cyclazocine but not with morphine, hydromorphone, oxymorphine, codeine, methadone, and meperidine. Butorphanol tartrate was administered intravenously (2 mg) to normal male volunteers. Serum butorphanol levels declined biexponentially with an average terminal half-life of 2.7 hr. Enzymatic serum hydrolysis prior to extraction yielded additional butorphanol, indicating the presence of butorphanol conjugates. The specificity of the assay for butorphanol was confirmed by GLC--mass fragmentography.

Optimized radioimmunoassay curve fitting program suitable for use on desktop calculators

A simplex search program for the logit-log parameters of radioimmunoassay calibration curves, suitable for use on a small desktop calculator, is described. The technique features a weighted least-square method to extract the maximum information out of the calibration data. A criterion for rejection of outliers is included.

An improved processing of radioimmunoassay data by means of a desk-top calculator. (1) Comparison of regression procedures applied to selected kinds of radioimmunoassay

By means of a programmable desk-top calculator, goodness-of-fit of 3 regression models, four-parameter logistic, quadratic logit-log and linear logit-log models, were evaluated by analysis of variance (F test) for data of 6 kinds of radioimmunoassays (RIA); thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), insulin (IRI), cortisol, triiodothyronine (T3). Scatchard plot analyses were made with the representative data of these RIAs in order to find the best choice of regression model in relation to the characteristics of antigen-antibody reaction. The analysis of goodness-of-fit of the regression models by means of an F test disclosed the relation between the choice of regression models and the kinds of RIA, which could be grouped into 3 types: (1) almost identical degree of fit with any of 3 regression models (FSH and T3), (2) more or less equal degree of satisfactory fit with the logistic and quadratic logit-log models (TSH and cortisol), (3) best degree of fit with the aquadratic logit-log model among 3 (LH and IRI). The analysis of data with Scatchard plot discriminated 3 general types of curves; (1) linear (FSH) and T3), (2) linear with tail (TSH and cortisol) and (3) hyperbola (LH and IRI). From these findings, the following tentative conclusions were reached: RIA with linear pattern on Scatchard plot can be satisfactorily regressed with either of 3 models, RIA with linear with tail pattern regressed with either the logistic or quadratic logit-log model, and RIA with hyperbolic pattern regressed best with the quadratic logit-log model.